GNU Linux-libre 4.14.251-gnu1

[releases.git] / drivers / scsi / cxlflash / main.c

/*
 * CXL Flash Device Driver
 *
 * Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
 *             Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
 *
 * Copyright (C) 2015 IBM Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/delay.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/pci.h>

#include <asm/unaligned.h>

#include <misc/cxl.h>

#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>
#include <uapi/scsi/cxlflash_ioctl.h>

#include "main.h"
#include "sislite.h"
#include "common.h"

MODULE_DESCRIPTION(CXLFLASH_ADAPTER_NAME);
MODULE_AUTHOR("Manoj N. Kumar <manoj@linux.vnet.ibm.com>");
MODULE_AUTHOR("Matthew R. Ochs <mrochs@linux.vnet.ibm.com>");
MODULE_LICENSE("GPL");

static struct class *cxlflash_class;
static u32 cxlflash_major;
static DECLARE_BITMAP(cxlflash_minor, CXLFLASH_MAX_ADAPTERS);

/**
 * process_cmd_err() - command error handler
 * @cmd:        AFU command that experienced the error.
 * @scp:        SCSI command associated with the AFU command in error.
 *
 * Translates error bits from AFU command to SCSI command results.
 */
static void process_cmd_err(struct afu_cmd *cmd, struct scsi_cmnd *scp)
{
        struct afu *afu = cmd->parent;
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;
        struct sisl_ioarcb *ioarcb;
        struct sisl_ioasa *ioasa;
        u32 resid;

        if (unlikely(!cmd))
                return;

        ioarcb = &(cmd->rcb);
        ioasa = &(cmd->sa);

        if (ioasa->rc.flags & SISL_RC_FLAGS_UNDERRUN) {
                resid = ioasa->resid;
                scsi_set_resid(scp, resid);
                dev_dbg(dev, "%s: cmd underrun cmd = %p scp = %p, resid = %d\n",
                        __func__, cmd, scp, resid);
        }

        if (ioasa->rc.flags & SISL_RC_FLAGS_OVERRUN) {
                dev_dbg(dev, "%s: cmd underrun cmd = %p scp = %p\n",
                        __func__, cmd, scp);
                scp->result = (DID_ERROR << 16);
        }

        dev_dbg(dev, "%s: cmd failed afu_rc=%02x scsi_rc=%02x fc_rc=%02x "
                "afu_extra=%02x scsi_extra=%02x fc_extra=%02x\n", __func__,
                ioasa->rc.afu_rc, ioasa->rc.scsi_rc, ioasa->rc.fc_rc,
                ioasa->afu_extra, ioasa->scsi_extra, ioasa->fc_extra);

        if (ioasa->rc.scsi_rc) {
                /* We have a SCSI status */
                if (ioasa->rc.flags & SISL_RC_FLAGS_SENSE_VALID) {
                        memcpy(scp->sense_buffer, ioasa->sense_data,
                               SISL_SENSE_DATA_LEN);
                        scp->result = ioasa->rc.scsi_rc;
                } else
                        scp->result = ioasa->rc.scsi_rc | (DID_ERROR << 16);
        }

        /*
         * We encountered an error. Set scp->result based on nature
         * of error.
         */
        if (ioasa->rc.fc_rc) {
                /* We have an FC status */
                switch (ioasa->rc.fc_rc) {
                case SISL_FC_RC_LINKDOWN:
                        scp->result = (DID_REQUEUE << 16);
                        break;
                case SISL_FC_RC_RESID:
                        /* This indicates an FCP resid underrun */
                        if (!(ioasa->rc.flags & SISL_RC_FLAGS_OVERRUN)) {
                                /* If the SISL_RC_FLAGS_OVERRUN flag was set,
                                 * then we will handle this error else where.
                                 * If not then we must handle it here.
                                 * This is probably an AFU bug.
                                 */
                                scp->result = (DID_ERROR << 16);
                        }
                        break;
                case SISL_FC_RC_RESIDERR:
                        /* Resid mismatch between adapter and device */
                case SISL_FC_RC_TGTABORT:
                case SISL_FC_RC_ABORTOK:
                case SISL_FC_RC_ABORTFAIL:
                case SISL_FC_RC_NOLOGI:
                case SISL_FC_RC_ABORTPEND:
                case SISL_FC_RC_WRABORTPEND:
                case SISL_FC_RC_NOEXP:
                case SISL_FC_RC_INUSE:
                        scp->result = (DID_ERROR << 16);
                        break;
                }
        }

        if (ioasa->rc.afu_rc) {
                /* We have an AFU error */
                switch (ioasa->rc.afu_rc) {
                case SISL_AFU_RC_NO_CHANNELS:
                        scp->result = (DID_NO_CONNECT << 16);
                        break;
                case SISL_AFU_RC_DATA_DMA_ERR:
                        switch (ioasa->afu_extra) {
                        case SISL_AFU_DMA_ERR_PAGE_IN:
                                /* Retry */
                                scp->result = (DID_IMM_RETRY << 16);
                                break;
                        case SISL_AFU_DMA_ERR_INVALID_EA:
                        default:
                                scp->result = (DID_ERROR << 16);
                        }
                        break;
                case SISL_AFU_RC_OUT_OF_DATA_BUFS:
                        /* Retry */
                        scp->result = (DID_ALLOC_FAILURE << 16);
                        break;
                default:
                        scp->result = (DID_ERROR << 16);
                }
        }
}

/**
 * cmd_complete() - command completion handler
 * @cmd:        AFU command that has completed.
 *
 * For SCSI commands this routine prepares and submits commands that have
 * either completed or timed out to the SCSI stack. For internal commands
 * (TMF or AFU), this routine simply notifies the originator that the
 * command has completed.
 */
static void cmd_complete(struct afu_cmd *cmd)
{
        struct scsi_cmnd *scp;
        ulong lock_flags;
        struct afu *afu = cmd->parent;
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq = get_hwq(afu, cmd->hwq_index);

        spin_lock_irqsave(&hwq->hsq_slock, lock_flags);
        list_del(&cmd->list);
        spin_unlock_irqrestore(&hwq->hsq_slock, lock_flags);

        if (cmd->scp) {
                scp = cmd->scp;
                if (unlikely(cmd->sa.ioasc))
                        process_cmd_err(cmd, scp);
                else
                        scp->result = (DID_OK << 16);

                dev_dbg_ratelimited(dev, "%s:scp=%p result=%08x ioasc=%08x\n",
                                    __func__, scp, scp->result, cmd->sa.ioasc);
                scp->scsi_done(scp);
        } else if (cmd->cmd_tmf) {
                spin_lock_irqsave(&cfg->tmf_slock, lock_flags);
                cfg->tmf_active = false;
                wake_up_all_locked(&cfg->tmf_waitq);
                spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);
        } else
                complete(&cmd->cevent);
}

/**
 * flush_pending_cmds() - flush all pending commands on this hardware queue
 * @hwq:        Hardware queue to flush.
 *
 * The hardware send queue lock associated with this hardware queue must be
 * held when calling this routine.
 */
static void flush_pending_cmds(struct hwq *hwq)
{
        struct cxlflash_cfg *cfg = hwq->afu->parent;
        struct afu_cmd *cmd, *tmp;
        struct scsi_cmnd *scp;
        ulong lock_flags;

        list_for_each_entry_safe(cmd, tmp, &hwq->pending_cmds, list) {
                /* Bypass command when on a doneq, cmd_complete() will handle */
                if (!list_empty(&cmd->queue))
                        continue;

                list_del(&cmd->list);

                if (cmd->scp) {
                        scp = cmd->scp;
                        scp->result = (DID_IMM_RETRY << 16);
                        scp->scsi_done(scp);
                } else {
                        cmd->cmd_aborted = true;

                        if (cmd->cmd_tmf) {
                                spin_lock_irqsave(&cfg->tmf_slock, lock_flags);
                                cfg->tmf_active = false;
                                wake_up_all_locked(&cfg->tmf_waitq);
                                spin_unlock_irqrestore(&cfg->tmf_slock,
                                                       lock_flags);
                        } else
                                complete(&cmd->cevent);
                }
        }
}

/**
 * context_reset() - reset context via specified register
 * @hwq:        Hardware queue owning the context to be reset.
 * @reset_reg:  MMIO register to perform reset.
 *
 * When the reset is successful, the SISLite specification guarantees that
 * the AFU has aborted all currently pending I/O. Accordingly, these commands
 * must be flushed.
 *
 * Return: 0 on success, -errno on failure
 */
static int context_reset(struct hwq *hwq, __be64 __iomem *reset_reg)
{
        struct cxlflash_cfg *cfg = hwq->afu->parent;
        struct device *dev = &cfg->dev->dev;
        int rc = -ETIMEDOUT;
        int nretry = 0;
        u64 val = 0x1;
        ulong lock_flags;

        dev_dbg(dev, "%s: hwq=%p\n", __func__, hwq);

        spin_lock_irqsave(&hwq->hsq_slock, lock_flags);

        writeq_be(val, reset_reg);
        do {
                val = readq_be(reset_reg);
                if ((val & 0x1) == 0x0) {
                        rc = 0;
                        break;
                }

                /* Double delay each time */
                udelay(1 << nretry);
        } while (nretry++ < MC_ROOM_RETRY_CNT);

        if (!rc)
                flush_pending_cmds(hwq);

        spin_unlock_irqrestore(&hwq->hsq_slock, lock_flags);

        dev_dbg(dev, "%s: returning rc=%d, val=%016llx nretry=%d\n",
                __func__, rc, val, nretry);
        return rc;
}

/**
 * context_reset_ioarrin() - reset context via IOARRIN register
 * @hwq:        Hardware queue owning the context to be reset.
 *
 * Return: 0 on success, -errno on failure
 */
static int context_reset_ioarrin(struct hwq *hwq)
{
        return context_reset(hwq, &hwq->host_map->ioarrin);
}

/**
 * context_reset_sq() - reset context via SQ_CONTEXT_RESET register
 * @hwq:        Hardware queue owning the context to be reset.
 *
 * Return: 0 on success, -errno on failure
 */
static int context_reset_sq(struct hwq *hwq)
{
        return context_reset(hwq, &hwq->host_map->sq_ctx_reset);
}

/**
 * send_cmd_ioarrin() - sends an AFU command via IOARRIN register
 * @afu:        AFU associated with the host.
 * @cmd:        AFU command to send.
 *
 * Return:
 *      0 on success, SCSI_MLQUEUE_HOST_BUSY on failure
 */
static int send_cmd_ioarrin(struct afu *afu, struct afu_cmd *cmd)
{
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq = get_hwq(afu, cmd->hwq_index);
        int rc = 0;
        s64 room;
        ulong lock_flags;

        /*
         * To avoid the performance penalty of MMIO, spread the update of
         * 'room' over multiple commands.
         */
        spin_lock_irqsave(&hwq->hsq_slock, lock_flags);
        if (--hwq->room < 0) {
                room = readq_be(&hwq->host_map->cmd_room);
                if (room <= 0) {
                        dev_dbg_ratelimited(dev, "%s: no cmd_room to send "
                                            "0x%02X, room=0x%016llX\n",
                                            __func__, cmd->rcb.cdb[0], room);
                        hwq->room = 0;
                        rc = SCSI_MLQUEUE_HOST_BUSY;
                        goto out;
                }
                hwq->room = room - 1;
        }

        list_add(&cmd->list, &hwq->pending_cmds);
        writeq_be((u64)&cmd->rcb, &hwq->host_map->ioarrin);
out:
        spin_unlock_irqrestore(&hwq->hsq_slock, lock_flags);
        dev_dbg(dev, "%s: cmd=%p len=%u ea=%016llx rc=%d\n", __func__,
                cmd, cmd->rcb.data_len, cmd->rcb.data_ea, rc);
        return rc;
}

/**
 * send_cmd_sq() - sends an AFU command via SQ ring
 * @afu:        AFU associated with the host.
 * @cmd:        AFU command to send.
 *
 * Return:
 *      0 on success, SCSI_MLQUEUE_HOST_BUSY on failure
 */
static int send_cmd_sq(struct afu *afu, struct afu_cmd *cmd)
{
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq = get_hwq(afu, cmd->hwq_index);
        int rc = 0;
        int newval;
        ulong lock_flags;

        newval = atomic_dec_if_positive(&hwq->hsq_credits);
        if (newval <= 0) {
                rc = SCSI_MLQUEUE_HOST_BUSY;
                goto out;
        }

        cmd->rcb.ioasa = &cmd->sa;

        spin_lock_irqsave(&hwq->hsq_slock, lock_flags);

        *hwq->hsq_curr = cmd->rcb;
        if (hwq->hsq_curr < hwq->hsq_end)
                hwq->hsq_curr++;
        else
                hwq->hsq_curr = hwq->hsq_start;

        list_add(&cmd->list, &hwq->pending_cmds);
        writeq_be((u64)hwq->hsq_curr, &hwq->host_map->sq_tail);

        spin_unlock_irqrestore(&hwq->hsq_slock, lock_flags);
out:
        dev_dbg(dev, "%s: cmd=%p len=%u ea=%016llx ioasa=%p rc=%d curr=%p "
               "head=%016llx tail=%016llx\n", __func__, cmd, cmd->rcb.data_len,
               cmd->rcb.data_ea, cmd->rcb.ioasa, rc, hwq->hsq_curr,
               readq_be(&hwq->host_map->sq_head),
               readq_be(&hwq->host_map->sq_tail));
        return rc;
}

/**
 * wait_resp() - polls for a response or timeout to a sent AFU command
 * @afu:        AFU associated with the host.
 * @cmd:        AFU command that was sent.
 *
 * Return: 0 on success, -errno on failure
 */
static int wait_resp(struct afu *afu, struct afu_cmd *cmd)
{
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;
        int rc = 0;
        ulong timeout = msecs_to_jiffies(cmd->rcb.timeout * 2 * 1000);

        timeout = wait_for_completion_timeout(&cmd->cevent, timeout);
        if (!timeout)
                rc = -ETIMEDOUT;

        if (cmd->cmd_aborted)
                rc = -EAGAIN;

        if (unlikely(cmd->sa.ioasc != 0)) {
                dev_err(dev, "%s: cmd %02x failed, ioasc=%08x\n",
                        __func__, cmd->rcb.cdb[0], cmd->sa.ioasc);
                rc = -EIO;
        }

        return rc;
}

/**
 * cmd_to_target_hwq() - selects a target hardware queue for a SCSI command
 * @host:       SCSI host associated with device.
 * @scp:        SCSI command to send.
 * @afu:        SCSI command to send.
 *
 * Hashes a command based upon the hardware queue mode.
 *
 * Return: Trusted index of target hardware queue
 */
static u32 cmd_to_target_hwq(struct Scsi_Host *host, struct scsi_cmnd *scp,
                             struct afu *afu)
{
        u32 tag;
        u32 hwq = 0;

        if (afu->num_hwqs == 1)
                return 0;

        switch (afu->hwq_mode) {
        case HWQ_MODE_RR:
                hwq = afu->hwq_rr_count++ % afu->num_hwqs;
                break;
        case HWQ_MODE_TAG:
                tag = blk_mq_unique_tag(scp->request);
                hwq = blk_mq_unique_tag_to_hwq(tag);
                break;
        case HWQ_MODE_CPU:
                hwq = smp_processor_id() % afu->num_hwqs;
                break;
        default:
                WARN_ON_ONCE(1);
        }

        return hwq;
}

/**
 * send_tmf() - sends a Task Management Function (TMF)
 * @cfg:        Internal structure associated with the host.
 * @sdev:       SCSI device destined for TMF.
 * @tmfcmd:     TMF command to send.
 *
 * Return:
 *      0 on success, SCSI_MLQUEUE_HOST_BUSY or -errno on failure
 */
static int send_tmf(struct cxlflash_cfg *cfg, struct scsi_device *sdev,
                    u64 tmfcmd)
{
        struct afu *afu = cfg->afu;
        struct afu_cmd *cmd = NULL;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq = get_hwq(afu, PRIMARY_HWQ);
        char *buf = NULL;
        ulong lock_flags;
        int rc = 0;
        ulong to;

        buf = kzalloc(sizeof(*cmd) + __alignof__(*cmd) - 1, GFP_KERNEL);
        if (unlikely(!buf)) {
                dev_err(dev, "%s: no memory for command\n", __func__);
                rc = -ENOMEM;
                goto out;
        }

        cmd = (struct afu_cmd *)PTR_ALIGN(buf, __alignof__(*cmd));
        INIT_LIST_HEAD(&cmd->queue);

        /* When Task Management Function is active do not send another */
        spin_lock_irqsave(&cfg->tmf_slock, lock_flags);
        if (cfg->tmf_active)
                wait_event_interruptible_lock_irq(cfg->tmf_waitq,
                                                  !cfg->tmf_active,
                                                  cfg->tmf_slock);
        cfg->tmf_active = true;
        spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);

        cmd->parent = afu;
        cmd->cmd_tmf = true;
        cmd->hwq_index = hwq->index;

        cmd->rcb.ctx_id = hwq->ctx_hndl;
        cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
        cmd->rcb.port_sel = CHAN2PORTMASK(sdev->channel);
        cmd->rcb.lun_id = lun_to_lunid(sdev->lun);
        cmd->rcb.req_flags = (SISL_REQ_FLAGS_PORT_LUN_ID |
                              SISL_REQ_FLAGS_SUP_UNDERRUN |
                              SISL_REQ_FLAGS_TMF_CMD);
        memcpy(cmd->rcb.cdb, &tmfcmd, sizeof(tmfcmd));

        rc = afu->send_cmd(afu, cmd);
        if (unlikely(rc)) {
                spin_lock_irqsave(&cfg->tmf_slock, lock_flags);
                cfg->tmf_active = false;
                spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);
                goto out;
        }

        spin_lock_irqsave(&cfg->tmf_slock, lock_flags);
        to = msecs_to_jiffies(5000);
        to = wait_event_interruptible_lock_irq_timeout(cfg->tmf_waitq,
                                                       !cfg->tmf_active,
                                                       cfg->tmf_slock,
                                                       to);
        if (!to) {
                dev_err(dev, "%s: TMF timed out\n", __func__);
                rc = -ETIMEDOUT;
        } else if (cmd->cmd_aborted) {
                dev_err(dev, "%s: TMF aborted\n", __func__);
                rc = -EAGAIN;
        } else if (cmd->sa.ioasc) {
                dev_err(dev, "%s: TMF failed ioasc=%08x\n",
                        __func__, cmd->sa.ioasc);
                rc = -EIO;
        }
        cfg->tmf_active = false;
        spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);
out:
        kfree(buf);
        return rc;
}

/**
 * cxlflash_driver_info() - information handler for this host driver
 * @host:       SCSI host associated with device.
 *
 * Return: A string describing the device.
 */
static const char *cxlflash_driver_info(struct Scsi_Host *host)
{
        return CXLFLASH_ADAPTER_NAME;
}

/**
 * cxlflash_queuecommand() - sends a mid-layer request
 * @host:       SCSI host associated with device.
 * @scp:        SCSI command to send.
 *
 * Return: 0 on success, SCSI_MLQUEUE_HOST_BUSY on failure
 */
static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp)
{
        struct cxlflash_cfg *cfg = shost_priv(host);
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct afu_cmd *cmd = sc_to_afuci(scp);
        struct scatterlist *sg = scsi_sglist(scp);
        int hwq_index = cmd_to_target_hwq(host, scp, afu);
        struct hwq *hwq = get_hwq(afu, hwq_index);
        u16 req_flags = SISL_REQ_FLAGS_SUP_UNDERRUN;
        ulong lock_flags;
        int rc = 0;

        dev_dbg_ratelimited(dev, "%s: (scp=%p) %d/%d/%d/%llu "
                            "cdb=(%08x-%08x-%08x-%08x)\n",
                            __func__, scp, host->host_no, scp->device->channel,
                            scp->device->id, scp->device->lun,
                            get_unaligned_be32(&((u32 *)scp->cmnd)[0]),
                            get_unaligned_be32(&((u32 *)scp->cmnd)[1]),
                            get_unaligned_be32(&((u32 *)scp->cmnd)[2]),
                            get_unaligned_be32(&((u32 *)scp->cmnd)[3]));

        /*
         * If a Task Management Function is active, wait for it to complete
         * before continuing with regular commands.
         */
        spin_lock_irqsave(&cfg->tmf_slock, lock_flags);
        if (cfg->tmf_active) {
                spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);
                rc = SCSI_MLQUEUE_HOST_BUSY;
                goto out;
        }
        spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);

        switch (cfg->state) {
        case STATE_PROBING:
        case STATE_PROBED:
        case STATE_RESET:
                dev_dbg_ratelimited(dev, "%s: device is in reset\n", __func__);
                rc = SCSI_MLQUEUE_HOST_BUSY;
                goto out;
        case STATE_FAILTERM:
                dev_dbg_ratelimited(dev, "%s: device has failed\n", __func__);
                scp->result = (DID_NO_CONNECT << 16);
                scp->scsi_done(scp);
                rc = 0;
                goto out;
        default:
                break;
        }

        if (likely(sg)) {
                cmd->rcb.data_len = sg->length;
                cmd->rcb.data_ea = (uintptr_t)sg_virt(sg);
        }

        cmd->scp = scp;
        cmd->parent = afu;
        cmd->hwq_index = hwq_index;

        cmd->sa.ioasc = 0;
        cmd->rcb.ctx_id = hwq->ctx_hndl;
        cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
        cmd->rcb.port_sel = CHAN2PORTMASK(scp->device->channel);
        cmd->rcb.lun_id = lun_to_lunid(scp->device->lun);

        if (scp->sc_data_direction == DMA_TO_DEVICE)
                req_flags |= SISL_REQ_FLAGS_HOST_WRITE;

        cmd->rcb.req_flags = req_flags;
        memcpy(cmd->rcb.cdb, scp->cmnd, sizeof(cmd->rcb.cdb));

        rc = afu->send_cmd(afu, cmd);
out:
        return rc;
}

/**
 * cxlflash_wait_for_pci_err_recovery() - wait for error recovery during probe
 * @cfg:        Internal structure associated with the host.
 */
static void cxlflash_wait_for_pci_err_recovery(struct cxlflash_cfg *cfg)
{
        struct pci_dev *pdev = cfg->dev;

        if (pci_channel_offline(pdev))
                wait_event_timeout(cfg->reset_waitq,
                                   !pci_channel_offline(pdev),
                                   CXLFLASH_PCI_ERROR_RECOVERY_TIMEOUT);
}

/**
 * free_mem() - free memory associated with the AFU
 * @cfg:        Internal structure associated with the host.
 */
static void free_mem(struct cxlflash_cfg *cfg)
{
        struct afu *afu = cfg->afu;

        if (cfg->afu) {
                free_pages((ulong)afu, get_order(sizeof(struct afu)));
                cfg->afu = NULL;
        }
}

/**
 * cxlflash_reset_sync() - synchronizing point for asynchronous resets
 * @cfg:        Internal structure associated with the host.
 */
static void cxlflash_reset_sync(struct cxlflash_cfg *cfg)
{
        if (cfg->async_reset_cookie == 0)
                return;

        /* Wait until all async calls prior to this cookie have completed */
        async_synchronize_cookie(cfg->async_reset_cookie + 1);
        cfg->async_reset_cookie = 0;
}

/**
 * stop_afu() - stops the AFU command timers and unmaps the MMIO space
 * @cfg:        Internal structure associated with the host.
 *
 * Safe to call with AFU in a partially allocated/initialized state.
 *
 * Cancels scheduled worker threads, waits for any active internal AFU
 * commands to timeout, disables IRQ polling and then unmaps the MMIO space.
 */
static void stop_afu(struct cxlflash_cfg *cfg)
{
        struct afu *afu = cfg->afu;
        struct hwq *hwq;
        int i;

        cancel_work_sync(&cfg->work_q);
        if (!current_is_async())
                cxlflash_reset_sync(cfg);

        if (likely(afu)) {
                while (atomic_read(&afu->cmds_active))
                        ssleep(1);

                if (afu_is_irqpoll_enabled(afu)) {
                        for (i = 0; i < afu->num_hwqs; i++) {
                                hwq = get_hwq(afu, i);

                                irq_poll_disable(&hwq->irqpoll);
                        }
                }

                if (likely(afu->afu_map)) {
                        cxl_psa_unmap((void __iomem *)afu->afu_map);
                        afu->afu_map = NULL;
                }
        }
}

/**
 * term_intr() - disables all AFU interrupts
 * @cfg:        Internal structure associated with the host.
 * @level:      Depth of allocation, where to begin waterfall tear down.
 * @index:      Index of the hardware queue.
 *
 * Safe to call with AFU/MC in partially allocated/initialized state.
 */
static void term_intr(struct cxlflash_cfg *cfg, enum undo_level level,
                      u32 index)
{
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq;

        if (!afu) {
                dev_err(dev, "%s: returning with NULL afu\n", __func__);
                return;
        }

        hwq = get_hwq(afu, index);

        if (!hwq->ctx) {
                dev_err(dev, "%s: returning with NULL MC\n", __func__);
                return;
        }

        switch (level) {
        case UNMAP_THREE:
                /* SISL_MSI_ASYNC_ERROR is setup only for the primary HWQ */
                if (index == PRIMARY_HWQ)
                        cxl_unmap_afu_irq(hwq->ctx, 3, hwq);
        case UNMAP_TWO:
                cxl_unmap_afu_irq(hwq->ctx, 2, hwq);
        case UNMAP_ONE:
                cxl_unmap_afu_irq(hwq->ctx, 1, hwq);
        case FREE_IRQ:
                cxl_free_afu_irqs(hwq->ctx);
                /* fall through */
        case UNDO_NOOP:
                /* No action required */
                break;
        }
}

/**
 * term_mc() - terminates the master context
 * @cfg:        Internal structure associated with the host.
 * @index:      Index of the hardware queue.
 *
 * Safe to call with AFU/MC in partially allocated/initialized state.
 */
static void term_mc(struct cxlflash_cfg *cfg, u32 index)
{
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq;
        ulong lock_flags;

        if (!afu) {
                dev_err(dev, "%s: returning with NULL afu\n", __func__);
                return;
        }

        hwq = get_hwq(afu, index);

        if (!hwq->ctx) {
                dev_err(dev, "%s: returning with NULL MC\n", __func__);
                return;
        }

        WARN_ON(cxl_stop_context(hwq->ctx));
        if (index != PRIMARY_HWQ)
                WARN_ON(cxl_release_context(hwq->ctx));
        hwq->ctx = NULL;

        spin_lock_irqsave(&hwq->hsq_slock, lock_flags);
        flush_pending_cmds(hwq);
        spin_unlock_irqrestore(&hwq->hsq_slock, lock_flags);
}

/**
 * term_afu() - terminates the AFU
 * @cfg:        Internal structure associated with the host.
 *
 * Safe to call with AFU/MC in partially allocated/initialized state.
 */
static void term_afu(struct cxlflash_cfg *cfg)
{
        struct device *dev = &cfg->dev->dev;
        int k;

        /*
         * Tear down is carefully orchestrated to ensure
         * no interrupts can come in when the problem state
         * area is unmapped.
         *
         * 1) Disable all AFU interrupts for each master
         * 2) Unmap the problem state area
         * 3) Stop each master context
         */
        for (k = cfg->afu->num_hwqs - 1; k >= 0; k--)
                term_intr(cfg, UNMAP_THREE, k);

        stop_afu(cfg);

        for (k = cfg->afu->num_hwqs - 1; k >= 0; k--)
                term_mc(cfg, k);

        dev_dbg(dev, "%s: returning\n", __func__);
}

/**
 * notify_shutdown() - notifies device of pending shutdown
 * @cfg:        Internal structure associated with the host.
 * @wait:       Whether to wait for shutdown processing to complete.
 *
 * This function will notify the AFU that the adapter is being shutdown
 * and will wait for shutdown processing to complete if wait is true.
 * This notification should flush pending I/Os to the device and halt
 * further I/Os until the next AFU reset is issued and device restarted.
 */
static void notify_shutdown(struct cxlflash_cfg *cfg, bool wait)
{
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct dev_dependent_vals *ddv;
        __be64 __iomem *fc_port_regs;
        u64 reg, status;
        int i, retry_cnt = 0;

        ddv = (struct dev_dependent_vals *)cfg->dev_id->driver_data;
        if (!(ddv->flags & CXLFLASH_NOTIFY_SHUTDOWN))
                return;

        if (!afu || !afu->afu_map) {
                dev_dbg(dev, "%s: Problem state area not mapped\n", __func__);
                return;
        }

        /* Notify AFU */
        for (i = 0; i < cfg->num_fc_ports; i++) {
                fc_port_regs = get_fc_port_regs(cfg, i);

                reg = readq_be(&fc_port_regs[FC_CONFIG2 / 8]);
                reg |= SISL_FC_SHUTDOWN_NORMAL;
                writeq_be(reg, &fc_port_regs[FC_CONFIG2 / 8]);
        }

        if (!wait)
                return;

        /* Wait up to 1.5 seconds for shutdown processing to complete */
        for (i = 0; i < cfg->num_fc_ports; i++) {
                fc_port_regs = get_fc_port_regs(cfg, i);
                retry_cnt = 0;

                while (true) {
                        status = readq_be(&fc_port_regs[FC_STATUS / 8]);
                        if (status & SISL_STATUS_SHUTDOWN_COMPLETE)
                                break;
                        if (++retry_cnt >= MC_RETRY_CNT) {
                                dev_dbg(dev, "%s: port %d shutdown processing "
                                        "not yet completed\n", __func__, i);
                                break;
                        }
                        msleep(100 * retry_cnt);
                }
        }
}

/**
 * cxlflash_get_minor() - gets the first available minor number
 *
 * Return: Unique minor number that can be used to create the character device.
 */
static int cxlflash_get_minor(void)
{
        int minor;
        long bit;

        bit = find_first_zero_bit(cxlflash_minor, CXLFLASH_MAX_ADAPTERS);
        if (bit >= CXLFLASH_MAX_ADAPTERS)
                return -1;

        minor = bit & MINORMASK;
        set_bit(minor, cxlflash_minor);
        return minor;
}

/**
 * cxlflash_put_minor() - releases the minor number
 * @minor:      Minor number that is no longer needed.
 */
static void cxlflash_put_minor(int minor)
{
        clear_bit(minor, cxlflash_minor);
}

/**
 * cxlflash_release_chrdev() - release the character device for the host
 * @cfg:        Internal structure associated with the host.
 */
static void cxlflash_release_chrdev(struct cxlflash_cfg *cfg)
{
        device_unregister(cfg->chardev);
        cfg->chardev = NULL;
        cdev_del(&cfg->cdev);
        cxlflash_put_minor(MINOR(cfg->cdev.dev));
}

/**
 * cxlflash_remove() - PCI entry point to tear down host
 * @pdev:       PCI device associated with the host.
 *
 * Safe to use as a cleanup in partially allocated/initialized state. Note that
 * the reset_waitq is flushed as part of the stop/termination of user contexts.
 */
static void cxlflash_remove(struct pci_dev *pdev)
{
        struct cxlflash_cfg *cfg = pci_get_drvdata(pdev);
        struct device *dev = &pdev->dev;
        ulong lock_flags;

        if (!pci_is_enabled(pdev)) {
                dev_dbg(dev, "%s: Device is disabled\n", __func__);
                return;
        }

        /* Yield to running recovery threads before continuing with remove */
        wait_event(cfg->reset_waitq, cfg->state != STATE_RESET &&
                                     cfg->state != STATE_PROBING);
        spin_lock_irqsave(&cfg->tmf_slock, lock_flags);
        if (cfg->tmf_active)
                wait_event_interruptible_lock_irq(cfg->tmf_waitq,
                                                  !cfg->tmf_active,
                                                  cfg->tmf_slock);
        spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);

        /* Notify AFU and wait for shutdown processing to complete */
        notify_shutdown(cfg, true);

        cfg->state = STATE_FAILTERM;
        cxlflash_stop_term_user_contexts(cfg);

        switch (cfg->init_state) {
        case INIT_STATE_CDEV:
                cxlflash_release_chrdev(cfg);
        case INIT_STATE_SCSI:
                cxlflash_term_local_luns(cfg);
                scsi_remove_host(cfg->host);
        case INIT_STATE_AFU:
                term_afu(cfg);
        case INIT_STATE_PCI:
                pci_disable_device(pdev);
        case INIT_STATE_NONE:
                free_mem(cfg);
                scsi_host_put(cfg->host);
                break;
        }

        dev_dbg(dev, "%s: returning\n", __func__);
}

/**
 * alloc_mem() - allocates the AFU and its command pool
 * @cfg:        Internal structure associated with the host.
 *
 * A partially allocated state remains on failure.
 *
 * Return:
 *      0 on success
 *      -ENOMEM on failure to allocate memory
 */
static int alloc_mem(struct cxlflash_cfg *cfg)
{
        int rc = 0;
        struct device *dev = &cfg->dev->dev;

        /* AFU is ~28k, i.e. only one 64k page or up to seven 4k pages */
        cfg->afu = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
                                            get_order(sizeof(struct afu)));
        if (unlikely(!cfg->afu)) {
                dev_err(dev, "%s: cannot get %d free pages\n",
                        __func__, get_order(sizeof(struct afu)));
                rc = -ENOMEM;
                goto out;
        }
        cfg->afu->parent = cfg;
        cfg->afu->desired_hwqs = CXLFLASH_DEF_HWQS;
        cfg->afu->afu_map = NULL;
out:
        return rc;
}

/**
 * init_pci() - initializes the host as a PCI device
 * @cfg:        Internal structure associated with the host.
 *
 * Return: 0 on success, -errno on failure
 */
static int init_pci(struct cxlflash_cfg *cfg)
{
        struct pci_dev *pdev = cfg->dev;
        struct device *dev = &cfg->dev->dev;
        int rc = 0;

        rc = pci_enable_device(pdev);
        if (rc || pci_channel_offline(pdev)) {
                if (pci_channel_offline(pdev)) {
                        cxlflash_wait_for_pci_err_recovery(cfg);
                        rc = pci_enable_device(pdev);
                }

                if (rc) {
                        dev_err(dev, "%s: Cannot enable adapter\n", __func__);
                        cxlflash_wait_for_pci_err_recovery(cfg);
                        goto out;
                }
        }

out:
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * init_scsi() - adds the host to the SCSI stack and kicks off host scan
 * @cfg:        Internal structure associated with the host.
 *
 * Return: 0 on success, -errno on failure
 */
static int init_scsi(struct cxlflash_cfg *cfg)
{
        struct pci_dev *pdev = cfg->dev;
        struct device *dev = &cfg->dev->dev;
        int rc = 0;

        rc = scsi_add_host(cfg->host, &pdev->dev);
        if (rc) {
                dev_err(dev, "%s: scsi_add_host failed rc=%d\n", __func__, rc);
                goto out;
        }

        scsi_scan_host(cfg->host);

out:
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * set_port_online() - transitions the specified host FC port to online state
 * @fc_regs:    Top of MMIO region defined for specified port.
 *
 * The provided MMIO region must be mapped prior to call. Online state means
 * that the FC link layer has synced, completed the handshaking process, and
 * is ready for login to start.
 */
static void set_port_online(__be64 __iomem *fc_regs)
{
        u64 cmdcfg;

        cmdcfg = readq_be(&fc_regs[FC_MTIP_CMDCONFIG / 8]);
        cmdcfg &= (~FC_MTIP_CMDCONFIG_OFFLINE); /* clear OFF_LINE */
        cmdcfg |= (FC_MTIP_CMDCONFIG_ONLINE);   /* set ON_LINE */
        writeq_be(cmdcfg, &fc_regs[FC_MTIP_CMDCONFIG / 8]);
}

/**
 * set_port_offline() - transitions the specified host FC port to offline state
 * @fc_regs:    Top of MMIO region defined for specified port.
 *
 * The provided MMIO region must be mapped prior to call.
 */
static void set_port_offline(__be64 __iomem *fc_regs)
{
        u64 cmdcfg;

        cmdcfg = readq_be(&fc_regs[FC_MTIP_CMDCONFIG / 8]);
        cmdcfg &= (~FC_MTIP_CMDCONFIG_ONLINE);  /* clear ON_LINE */
        cmdcfg |= (FC_MTIP_CMDCONFIG_OFFLINE);  /* set OFF_LINE */
        writeq_be(cmdcfg, &fc_regs[FC_MTIP_CMDCONFIG / 8]);
}

/**
 * wait_port_online() - waits for the specified host FC port come online
 * @fc_regs:    Top of MMIO region defined for specified port.
 * @delay_us:   Number of microseconds to delay between reading port status.
 * @nretry:     Number of cycles to retry reading port status.
 *
 * The provided MMIO region must be mapped prior to call. This will timeout
 * when the cable is not plugged in.
 *
 * Return:
 *      TRUE (1) when the specified port is online
 *      FALSE (0) when the specified port fails to come online after timeout
 */
static bool wait_port_online(__be64 __iomem *fc_regs, u32 delay_us, u32 nretry)
{
        u64 status;

        WARN_ON(delay_us < 1000);

        do {
                msleep(delay_us / 1000);
                status = readq_be(&fc_regs[FC_MTIP_STATUS / 8]);
                if (status == U64_MAX)
                        nretry /= 2;
        } while ((status & FC_MTIP_STATUS_MASK) != FC_MTIP_STATUS_ONLINE &&
                 nretry--);

        return ((status & FC_MTIP_STATUS_MASK) == FC_MTIP_STATUS_ONLINE);
}

/**
 * wait_port_offline() - waits for the specified host FC port go offline
 * @fc_regs:    Top of MMIO region defined for specified port.
 * @delay_us:   Number of microseconds to delay between reading port status.
 * @nretry:     Number of cycles to retry reading port status.
 *
 * The provided MMIO region must be mapped prior to call.
 *
 * Return:
 *      TRUE (1) when the specified port is offline
 *      FALSE (0) when the specified port fails to go offline after timeout
 */
static bool wait_port_offline(__be64 __iomem *fc_regs, u32 delay_us, u32 nretry)
{
        u64 status;

        WARN_ON(delay_us < 1000);

        do {
                msleep(delay_us / 1000);
                status = readq_be(&fc_regs[FC_MTIP_STATUS / 8]);
                if (status == U64_MAX)
                        nretry /= 2;
        } while ((status & FC_MTIP_STATUS_MASK) != FC_MTIP_STATUS_OFFLINE &&
                 nretry--);

        return ((status & FC_MTIP_STATUS_MASK) == FC_MTIP_STATUS_OFFLINE);
}

/**
 * afu_set_wwpn() - configures the WWPN for the specified host FC port
 * @afu:        AFU associated with the host that owns the specified FC port.
 * @port:       Port number being configured.
 * @fc_regs:    Top of MMIO region defined for specified port.
 * @wwpn:       The world-wide-port-number previously discovered for port.
 *
 * The provided MMIO region must be mapped prior to call. As part of the
 * sequence to configure the WWPN, the port is toggled offline and then back
 * online. This toggling action can cause this routine to delay up to a few
 * seconds. When configured to use the internal LUN feature of the AFU, a
 * failure to come online is overridden.
 */
static void afu_set_wwpn(struct afu *afu, int port, __be64 __iomem *fc_regs,
                         u64 wwpn)
{
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;

        set_port_offline(fc_regs);
        if (!wait_port_offline(fc_regs, FC_PORT_STATUS_RETRY_INTERVAL_US,
                               FC_PORT_STATUS_RETRY_CNT)) {
                dev_dbg(dev, "%s: wait on port %d to go offline timed out\n",
                        __func__, port);
        }

        writeq_be(wwpn, &fc_regs[FC_PNAME / 8]);

        set_port_online(fc_regs);
        if (!wait_port_online(fc_regs, FC_PORT_STATUS_RETRY_INTERVAL_US,
                              FC_PORT_STATUS_RETRY_CNT)) {
                dev_dbg(dev, "%s: wait on port %d to go online timed out\n",
                        __func__, port);
        }
}

/**
 * afu_link_reset() - resets the specified host FC port
 * @afu:        AFU associated with the host that owns the specified FC port.
 * @port:       Port number being configured.
 * @fc_regs:    Top of MMIO region defined for specified port.
 *
 * The provided MMIO region must be mapped prior to call. The sequence to
 * reset the port involves toggling it offline and then back online. This
 * action can cause this routine to delay up to a few seconds. An effort
 * is made to maintain link with the device by switching to host to use
 * the alternate port exclusively while the reset takes place.
 * failure to come online is overridden.
 */
static void afu_link_reset(struct afu *afu, int port, __be64 __iomem *fc_regs)
{
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;
        u64 port_sel;

        /* first switch the AFU to the other links, if any */
        port_sel = readq_be(&afu->afu_map->global.regs.afu_port_sel);
        port_sel &= ~(1ULL << port);
        writeq_be(port_sel, &afu->afu_map->global.regs.afu_port_sel);
        cxlflash_afu_sync(afu, 0, 0, AFU_GSYNC);

        set_port_offline(fc_regs);
        if (!wait_port_offline(fc_regs, FC_PORT_STATUS_RETRY_INTERVAL_US,
                               FC_PORT_STATUS_RETRY_CNT))
                dev_err(dev, "%s: wait on port %d to go offline timed out\n",
                        __func__, port);

        set_port_online(fc_regs);
        if (!wait_port_online(fc_regs, FC_PORT_STATUS_RETRY_INTERVAL_US,
                              FC_PORT_STATUS_RETRY_CNT))
                dev_err(dev, "%s: wait on port %d to go online timed out\n",
                        __func__, port);

        /* switch back to include this port */
        port_sel |= (1ULL << port);
        writeq_be(port_sel, &afu->afu_map->global.regs.afu_port_sel);
        cxlflash_afu_sync(afu, 0, 0, AFU_GSYNC);

        dev_dbg(dev, "%s: returning port_sel=%016llx\n", __func__, port_sel);
}

/**
 * afu_err_intr_init() - clears and initializes the AFU for error interrupts
 * @afu:        AFU associated with the host.
 */
static void afu_err_intr_init(struct afu *afu)
{
        struct cxlflash_cfg *cfg = afu->parent;
        __be64 __iomem *fc_port_regs;
        int i;
        struct hwq *hwq = get_hwq(afu, PRIMARY_HWQ);
        u64 reg;

        /* global async interrupts: AFU clears afu_ctrl on context exit
         * if async interrupts were sent to that context. This prevents
         * the AFU form sending further async interrupts when
         * there is
         * nobody to receive them.
         */

        /* mask all */
        writeq_be(-1ULL, &afu->afu_map->global.regs.aintr_mask);
        /* set LISN# to send and point to primary master context */
        reg = ((u64) (((hwq->ctx_hndl << 8) | SISL_MSI_ASYNC_ERROR)) << 40);

        if (afu->internal_lun)
                reg |= 1;       /* Bit 63 indicates local lun */
        writeq_be(reg, &afu->afu_map->global.regs.afu_ctrl);
        /* clear all */
        writeq_be(-1ULL, &afu->afu_map->global.regs.aintr_clear);
        /* unmask bits that are of interest */
        /* note: afu can send an interrupt after this step */
        writeq_be(SISL_ASTATUS_MASK, &afu->afu_map->global.regs.aintr_mask);
        /* clear again in case a bit came on after previous clear but before */
        /* unmask */
        writeq_be(-1ULL, &afu->afu_map->global.regs.aintr_clear);

        /* Clear/Set internal lun bits */
        fc_port_regs = get_fc_port_regs(cfg, 0);
        reg = readq_be(&fc_port_regs[FC_CONFIG2 / 8]);
        reg &= SISL_FC_INTERNAL_MASK;
        if (afu->internal_lun)
                reg |= ((u64)(afu->internal_lun - 1) << SISL_FC_INTERNAL_SHIFT);
        writeq_be(reg, &fc_port_regs[FC_CONFIG2 / 8]);

        /* now clear FC errors */
        for (i = 0; i < cfg->num_fc_ports; i++) {
                fc_port_regs = get_fc_port_regs(cfg, i);

                writeq_be(0xFFFFFFFFU, &fc_port_regs[FC_ERROR / 8]);
                writeq_be(0, &fc_port_regs[FC_ERRCAP / 8]);
        }

        /* sync interrupts for master's IOARRIN write */
        /* note that unlike asyncs, there can be no pending sync interrupts */
        /* at this time (this is a fresh context and master has not written */
        /* IOARRIN yet), so there is nothing to clear. */

        /* set LISN#, it is always sent to the context that wrote IOARRIN */
        for (i = 0; i < afu->num_hwqs; i++) {
                hwq = get_hwq(afu, i);

                reg = readq_be(&hwq->host_map->ctx_ctrl);
                WARN_ON((reg & SISL_CTX_CTRL_LISN_MASK) != 0);
                reg |= SISL_MSI_SYNC_ERROR;
                writeq_be(reg, &hwq->host_map->ctx_ctrl);
                writeq_be(SISL_ISTATUS_MASK, &hwq->host_map->intr_mask);
        }
}

/**
 * cxlflash_sync_err_irq() - interrupt handler for synchronous errors
 * @irq:        Interrupt number.
 * @data:       Private data provided at interrupt registration, the AFU.
 *
 * Return: Always return IRQ_HANDLED.
 */
static irqreturn_t cxlflash_sync_err_irq(int irq, void *data)
{
        struct hwq *hwq = (struct hwq *)data;
        struct cxlflash_cfg *cfg = hwq->afu->parent;
        struct device *dev = &cfg->dev->dev;
        u64 reg;
        u64 reg_unmasked;

        reg = readq_be(&hwq->host_map->intr_status);
        reg_unmasked = (reg & SISL_ISTATUS_UNMASK);

        if (reg_unmasked == 0UL) {
                dev_err(dev, "%s: spurious interrupt, intr_status=%016llx\n",
                        __func__, reg);
                goto cxlflash_sync_err_irq_exit;
        }

        dev_err(dev, "%s: unexpected interrupt, intr_status=%016llx\n",
                __func__, reg);

        writeq_be(reg_unmasked, &hwq->host_map->intr_clear);

cxlflash_sync_err_irq_exit:
        return IRQ_HANDLED;
}

/**
 * process_hrrq() - process the read-response queue
 * @afu:        AFU associated with the host.
 * @doneq:      Queue of commands harvested from the RRQ.
 * @budget:     Threshold of RRQ entries to process.
 *
 * This routine must be called holding the disabled RRQ spin lock.
 *
 * Return: The number of entries processed.
 */
static int process_hrrq(struct hwq *hwq, struct list_head *doneq, int budget)
{
        struct afu *afu = hwq->afu;
        struct afu_cmd *cmd;
        struct sisl_ioasa *ioasa;
        struct sisl_ioarcb *ioarcb;
        bool toggle = hwq->toggle;
        int num_hrrq = 0;
        u64 entry,
            *hrrq_start = hwq->hrrq_start,
            *hrrq_end = hwq->hrrq_end,
            *hrrq_curr = hwq->hrrq_curr;

        /* Process ready RRQ entries up to the specified budget (if any) */
        while (true) {
                entry = *hrrq_curr;

                if ((entry & SISL_RESP_HANDLE_T_BIT) != toggle)
                        break;

                entry &= ~SISL_RESP_HANDLE_T_BIT;

                if (afu_is_sq_cmd_mode(afu)) {
                        ioasa = (struct sisl_ioasa *)entry;
                        cmd = container_of(ioasa, struct afu_cmd, sa);
                } else {
                        ioarcb = (struct sisl_ioarcb *)entry;
                        cmd = container_of(ioarcb, struct afu_cmd, rcb);
                }

                list_add_tail(&cmd->queue, doneq);

                /* Advance to next entry or wrap and flip the toggle bit */
                if (hrrq_curr < hrrq_end)
                        hrrq_curr++;
                else {
                        hrrq_curr = hrrq_start;
                        toggle ^= SISL_RESP_HANDLE_T_BIT;
                }

                atomic_inc(&hwq->hsq_credits);
                num_hrrq++;

                if (budget > 0 && num_hrrq >= budget)
                        break;
        }

        hwq->hrrq_curr = hrrq_curr;
        hwq->toggle = toggle;

        return num_hrrq;
}

/**
 * process_cmd_doneq() - process a queue of harvested RRQ commands
 * @doneq:      Queue of completed commands.
 *
 * Note that upon return the queue can no longer be trusted.
 */
static void process_cmd_doneq(struct list_head *doneq)
{
        struct afu_cmd *cmd, *tmp;

        WARN_ON(list_empty(doneq));

        list_for_each_entry_safe(cmd, tmp, doneq, queue)
                cmd_complete(cmd);
}

/**
 * cxlflash_irqpoll() - process a queue of harvested RRQ commands
 * @irqpoll:    IRQ poll structure associated with queue to poll.
 * @budget:     Threshold of RRQ entries to process per poll.
 *
 * Return: The number of entries processed.
 */
static int cxlflash_irqpoll(struct irq_poll *irqpoll, int budget)
{
        struct hwq *hwq = container_of(irqpoll, struct hwq, irqpoll);
        unsigned long hrrq_flags;
        LIST_HEAD(doneq);
        int num_entries = 0;

        spin_lock_irqsave(&hwq->hrrq_slock, hrrq_flags);

        num_entries = process_hrrq(hwq, &doneq, budget);
        if (num_entries < budget)
                irq_poll_complete(irqpoll);

        spin_unlock_irqrestore(&hwq->hrrq_slock, hrrq_flags);

        process_cmd_doneq(&doneq);
        return num_entries;
}

/**
 * cxlflash_rrq_irq() - interrupt handler for read-response queue (normal path)
 * @irq:        Interrupt number.
 * @data:       Private data provided at interrupt registration, the AFU.
 *
 * Return: IRQ_HANDLED or IRQ_NONE when no ready entries found.
 */
static irqreturn_t cxlflash_rrq_irq(int irq, void *data)
{
        struct hwq *hwq = (struct hwq *)data;
        struct afu *afu = hwq->afu;
        unsigned long hrrq_flags;
        LIST_HEAD(doneq);
        int num_entries = 0;

        spin_lock_irqsave(&hwq->hrrq_slock, hrrq_flags);

        if (afu_is_irqpoll_enabled(afu)) {
                irq_poll_sched(&hwq->irqpoll);
                spin_unlock_irqrestore(&hwq->hrrq_slock, hrrq_flags);
                return IRQ_HANDLED;
        }

        num_entries = process_hrrq(hwq, &doneq, -1);
        spin_unlock_irqrestore(&hwq->hrrq_slock, hrrq_flags);

        if (num_entries == 0)
                return IRQ_NONE;

        process_cmd_doneq(&doneq);
        return IRQ_HANDLED;
}

/*
 * Asynchronous interrupt information table
 *
 * NOTE:
 *      - Order matters here as this array is indexed by bit position.
 *
 *      - The checkpatch script considers the BUILD_SISL_ASTATUS_FC_PORT macro
 *        as complex and complains due to a lack of parentheses/braces.
 */
#define ASTATUS_FC(_a, _b, _c, _d)                                       \
        { SISL_ASTATUS_FC##_a##_##_b, _c, _a, (_d) }

#define BUILD_SISL_ASTATUS_FC_PORT(_a)                                   \
        ASTATUS_FC(_a, LINK_UP, "link up", 0),                           \
        ASTATUS_FC(_a, LINK_DN, "link down", 0),                         \
        ASTATUS_FC(_a, LOGI_S, "login succeeded", SCAN_HOST),            \
        ASTATUS_FC(_a, LOGI_F, "login failed", CLR_FC_ERROR),            \
        ASTATUS_FC(_a, LOGI_R, "login timed out, retrying", LINK_RESET), \
        ASTATUS_FC(_a, CRC_T, "CRC threshold exceeded", LINK_RESET),     \
        ASTATUS_FC(_a, LOGO, "target initiated LOGO", 0),                \
        ASTATUS_FC(_a, OTHER, "other error", CLR_FC_ERROR | LINK_RESET)

static const struct asyc_intr_info ainfo[] = {
        BUILD_SISL_ASTATUS_FC_PORT(1),
        BUILD_SISL_ASTATUS_FC_PORT(0),
        BUILD_SISL_ASTATUS_FC_PORT(3),
        BUILD_SISL_ASTATUS_FC_PORT(2)
};

/**
 * cxlflash_async_err_irq() - interrupt handler for asynchronous errors
 * @irq:        Interrupt number.
 * @data:       Private data provided at interrupt registration, the AFU.
 *
 * Return: Always return IRQ_HANDLED.
 */
static irqreturn_t cxlflash_async_err_irq(int irq, void *data)
{
        struct hwq *hwq = (struct hwq *)data;
        struct afu *afu = hwq->afu;
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;
        const struct asyc_intr_info *info;
        struct sisl_global_map __iomem *global = &afu->afu_map->global;
        __be64 __iomem *fc_port_regs;
        u64 reg_unmasked;
        u64 reg;
        u64 bit;
        u8 port;

        reg = readq_be(&global->regs.aintr_status);
        reg_unmasked = (reg & SISL_ASTATUS_UNMASK);

        if (unlikely(reg_unmasked == 0)) {
                dev_err(dev, "%s: spurious interrupt, aintr_status=%016llx\n",
                        __func__, reg);
                goto out;
        }

        /* FYI, it is 'okay' to clear AFU status before FC_ERROR */
        writeq_be(reg_unmasked, &global->regs.aintr_clear);

        /* Check each bit that is on */
        for_each_set_bit(bit, (ulong *)&reg_unmasked, BITS_PER_LONG) {
                if (unlikely(bit >= ARRAY_SIZE(ainfo))) {
                        WARN_ON_ONCE(1);
                        continue;
                }

                info = &ainfo[bit];
                if (unlikely(info->status != 1ULL << bit)) {
                        WARN_ON_ONCE(1);
                        continue;
                }

                port = info->port;
                fc_port_regs = get_fc_port_regs(cfg, port);

                dev_err(dev, "%s: FC Port %d -> %s, fc_status=%016llx\n",
                        __func__, port, info->desc,
                       readq_be(&fc_port_regs[FC_STATUS / 8]));

                /*
                 * Do link reset first, some OTHER errors will set FC_ERROR
                 * again if cleared before or w/o a reset
                 */
                if (info->action & LINK_RESET) {
                        dev_err(dev, "%s: FC Port %d: resetting link\n",
                                __func__, port);
                        cfg->lr_state = LINK_RESET_REQUIRED;
                        cfg->lr_port = port;
                        schedule_work(&cfg->work_q);
                }

                if (info->action & CLR_FC_ERROR) {
                        reg = readq_be(&fc_port_regs[FC_ERROR / 8]);

                        /*
                         * Since all errors are unmasked, FC_ERROR and FC_ERRCAP
                         * should be the same and tracing one is sufficient.
                         */

                        dev_err(dev, "%s: fc %d: clearing fc_error=%016llx\n",
                                __func__, port, reg);

                        writeq_be(reg, &fc_port_regs[FC_ERROR / 8]);
                        writeq_be(0, &fc_port_regs[FC_ERRCAP / 8]);
                }

                if (info->action & SCAN_HOST) {
                        atomic_inc(&cfg->scan_host_needed);
                        schedule_work(&cfg->work_q);
                }
        }

out:
        return IRQ_HANDLED;
}

/**
 * start_context() - starts the master context
 * @cfg:        Internal structure associated with the host.
 * @index:      Index of the hardware queue.
 *
 * Return: A success or failure value from CXL services.
 */
static int start_context(struct cxlflash_cfg *cfg, u32 index)
{
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq = get_hwq(cfg->afu, index);
        int rc = 0;

        rc = cxl_start_context(hwq->ctx,
                               hwq->work.work_element_descriptor,
                               NULL);

        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * read_vpd() - obtains the WWPNs from VPD
 * @cfg:        Internal structure associated with the host.
 * @wwpn:       Array of size MAX_FC_PORTS to pass back WWPNs
 *
 * Return: 0 on success, -errno on failure
 */
static int read_vpd(struct cxlflash_cfg *cfg, u64 wwpn[])
{
        struct device *dev = &cfg->dev->dev;
        struct pci_dev *pdev = cfg->dev;
        int rc = 0;
        int ro_start, ro_size, i, j, k;
        ssize_t vpd_size;
        char vpd_data[CXLFLASH_VPD_LEN];
        char tmp_buf[WWPN_BUF_LEN] = { 0 };
        char *wwpn_vpd_tags[MAX_FC_PORTS] = { "V5", "V6", "V7", "V8" };

        /* Get the VPD data from the device */
        vpd_size = cxl_read_adapter_vpd(pdev, vpd_data, sizeof(vpd_data));
        if (unlikely(vpd_size <= 0)) {
                dev_err(dev, "%s: Unable to read VPD (size = %ld)\n",
                        __func__, vpd_size);
                rc = -ENODEV;
                goto out;
        }

        /* Get the read only section offset */
        ro_start = pci_vpd_find_tag(vpd_data, 0, vpd_size,
                                    PCI_VPD_LRDT_RO_DATA);
        if (unlikely(ro_start < 0)) {
                dev_err(dev, "%s: VPD Read-only data not found\n", __func__);
                rc = -ENODEV;
                goto out;
        }

        /* Get the read only section size, cap when extends beyond read VPD */
        ro_size = pci_vpd_lrdt_size(&vpd_data[ro_start]);
        j = ro_size;
        i = ro_start + PCI_VPD_LRDT_TAG_SIZE;
        if (unlikely((i + j) > vpd_size)) {
                dev_dbg(dev, "%s: Might need to read more VPD (%d > %ld)\n",
                        __func__, (i + j), vpd_size);
                ro_size = vpd_size - i;
        }

        /*
         * Find the offset of the WWPN tag within the read only
         * VPD data and validate the found field (partials are
         * no good to us). Convert the ASCII data to an integer
         * value. Note that we must copy to a temporary buffer
         * because the conversion service requires that the ASCII
         * string be terminated.
         */
        for (k = 0; k < cfg->num_fc_ports; k++) {
                j = ro_size;
                i = ro_start + PCI_VPD_LRDT_TAG_SIZE;

                i = pci_vpd_find_info_keyword(vpd_data, i, j, wwpn_vpd_tags[k]);
                if (unlikely(i < 0)) {
                        dev_err(dev, "%s: Port %d WWPN not found in VPD\n",
                                __func__, k);
                        rc = -ENODEV;
                        goto out;
                }

                j = pci_vpd_info_field_size(&vpd_data[i]);
                i += PCI_VPD_INFO_FLD_HDR_SIZE;
                if (unlikely((i + j > vpd_size) || (j != WWPN_LEN))) {
                        dev_err(dev, "%s: Port %d WWPN incomplete or bad VPD\n",
                                __func__, k);
                        rc = -ENODEV;
                        goto out;
                }

                memcpy(tmp_buf, &vpd_data[i], WWPN_LEN);
                rc = kstrtoul(tmp_buf, WWPN_LEN, (ulong *)&wwpn[k]);
                if (unlikely(rc)) {
                        dev_err(dev, "%s: WWPN conversion failed for port %d\n",
                                __func__, k);
                        rc = -ENODEV;
                        goto out;
                }

                dev_dbg(dev, "%s: wwpn%d=%016llx\n", __func__, k, wwpn[k]);
        }

out:
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * init_pcr() - initialize the provisioning and control registers
 * @cfg:        Internal structure associated with the host.
 *
 * Also sets up fast access to the mapped registers and initializes AFU
 * command fields that never change.
 */
static void init_pcr(struct cxlflash_cfg *cfg)
{
        struct afu *afu = cfg->afu;
        struct sisl_ctrl_map __iomem *ctrl_map;
        struct hwq *hwq;
        int i;

        for (i = 0; i < MAX_CONTEXT; i++) {
                ctrl_map = &afu->afu_map->ctrls[i].ctrl;
                /* Disrupt any clients that could be running */
                /* e.g. clients that survived a master restart */
                writeq_be(0, &ctrl_map->rht_start);
                writeq_be(0, &ctrl_map->rht_cnt_id);
                writeq_be(0, &ctrl_map->ctx_cap);
        }

        /* Copy frequently used fields into hwq */
        for (i = 0; i < afu->num_hwqs; i++) {
                hwq = get_hwq(afu, i);

                hwq->ctx_hndl = (u16) cxl_process_element(hwq->ctx);
                hwq->host_map = &afu->afu_map->hosts[hwq->ctx_hndl].host;
                hwq->ctrl_map = &afu->afu_map->ctrls[hwq->ctx_hndl].ctrl;

                /* Program the Endian Control for the master context */
                writeq_be(SISL_ENDIAN_CTRL, &hwq->host_map->endian_ctrl);
        }
}

/**
 * init_global() - initialize AFU global registers
 * @cfg:        Internal structure associated with the host.
 */
static int init_global(struct cxlflash_cfg *cfg)
{
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq;
        struct sisl_host_map __iomem *hmap;
        __be64 __iomem *fc_port_regs;
        u64 wwpn[MAX_FC_PORTS]; /* wwpn of AFU ports */
        int i = 0, num_ports = 0;
        int rc = 0;
        u64 reg;

        rc = read_vpd(cfg, &wwpn[0]);
        if (rc) {
                dev_err(dev, "%s: could not read vpd rc=%d\n", __func__, rc);
                goto out;
        }

        /* Set up RRQ and SQ in HWQ for master issued cmds */
        for (i = 0; i < afu->num_hwqs; i++) {
                hwq = get_hwq(afu, i);
                hmap = hwq->host_map;

                writeq_be((u64) hwq->hrrq_start, &hmap->rrq_start);
                writeq_be((u64) hwq->hrrq_end, &hmap->rrq_end);

                if (afu_is_sq_cmd_mode(afu)) {
                        writeq_be((u64)hwq->hsq_start, &hmap->sq_start);
                        writeq_be((u64)hwq->hsq_end, &hmap->sq_end);
                }
        }

        /* AFU configuration */
        reg = readq_be(&afu->afu_map->global.regs.afu_config);
        reg |= SISL_AFUCONF_AR_ALL|SISL_AFUCONF_ENDIAN;
        /* enable all auto retry options and control endianness */
        /* leave others at default: */
        /* CTX_CAP write protected, mbox_r does not clear on read and */
        /* checker on if dual afu */
        writeq_be(reg, &afu->afu_map->global.regs.afu_config);

        /* Global port select: select either port */
        if (afu->internal_lun) {
                /* Only use port 0 */
                writeq_be(PORT0, &afu->afu_map->global.regs.afu_port_sel);
                num_ports = 0;
        } else {
                writeq_be(PORT_MASK(cfg->num_fc_ports),
                          &afu->afu_map->global.regs.afu_port_sel);
                num_ports = cfg->num_fc_ports;
        }

        for (i = 0; i < num_ports; i++) {
                fc_port_regs = get_fc_port_regs(cfg, i);

                /* Unmask all errors (but they are still masked at AFU) */
                writeq_be(0, &fc_port_regs[FC_ERRMSK / 8]);
                /* Clear CRC error cnt & set a threshold */
                (void)readq_be(&fc_port_regs[FC_CNT_CRCERR / 8]);
                writeq_be(MC_CRC_THRESH, &fc_port_regs[FC_CRC_THRESH / 8]);

                /* Set WWPNs. If already programmed, wwpn[i] is 0 */
                if (wwpn[i] != 0)
                        afu_set_wwpn(afu, i, &fc_port_regs[0], wwpn[i]);
                /* Programming WWPN back to back causes additional
                 * offline/online transitions and a PLOGI
                 */
                msleep(100);
        }

        /* Set up master's own CTX_CAP to allow real mode, host translation */
        /* tables, afu cmds and read/write GSCSI cmds. */
        /* First, unlock ctx_cap write by reading mbox */
        for (i = 0; i < afu->num_hwqs; i++) {
                hwq = get_hwq(afu, i);

                (void)readq_be(&hwq->ctrl_map->mbox_r); /* unlock ctx_cap */
                writeq_be((SISL_CTX_CAP_REAL_MODE | SISL_CTX_CAP_HOST_XLATE |
                        SISL_CTX_CAP_READ_CMD | SISL_CTX_CAP_WRITE_CMD |
                        SISL_CTX_CAP_AFU_CMD | SISL_CTX_CAP_GSCSI_CMD),
                        &hwq->ctrl_map->ctx_cap);
        }

        /*
         * Determine write-same unmap support for host by evaluating the unmap
         * sector support bit of the context control register associated with
         * the primary hardware queue. Note that while this status is reflected
         * in a context register, the outcome can be assumed to be host-wide.
         */
        hwq = get_hwq(afu, PRIMARY_HWQ);
        reg = readq_be(&hwq->host_map->ctx_ctrl);
        if (reg & SISL_CTX_CTRL_UNMAP_SECTOR)
                cfg->ws_unmap = true;

        /* Initialize heartbeat */
        afu->hb = readq_be(&afu->afu_map->global.regs.afu_hb);
out:
        return rc;
}

/**
 * start_afu() - initializes and starts the AFU
 * @cfg:        Internal structure associated with the host.
 */
static int start_afu(struct cxlflash_cfg *cfg)
{
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq;
        int rc = 0;
        int i;

        init_pcr(cfg);

        /* Initialize each HWQ */
        for (i = 0; i < afu->num_hwqs; i++) {
                hwq = get_hwq(afu, i);

                /* After an AFU reset, RRQ entries are stale, clear them */
                memset(&hwq->rrq_entry, 0, sizeof(hwq->rrq_entry));

                /* Initialize RRQ pointers */
                hwq->hrrq_start = &hwq->rrq_entry[0];
                hwq->hrrq_end = &hwq->rrq_entry[NUM_RRQ_ENTRY - 1];
                hwq->hrrq_curr = hwq->hrrq_start;
                hwq->toggle = 1;

                /* Initialize spin locks */
                spin_lock_init(&hwq->hrrq_slock);
                spin_lock_init(&hwq->hsq_slock);

                /* Initialize SQ */
                if (afu_is_sq_cmd_mode(afu)) {
                        memset(&hwq->sq, 0, sizeof(hwq->sq));
                        hwq->hsq_start = &hwq->sq[0];
                        hwq->hsq_end = &hwq->sq[NUM_SQ_ENTRY - 1];
                        hwq->hsq_curr = hwq->hsq_start;

                        atomic_set(&hwq->hsq_credits, NUM_SQ_ENTRY - 1);
                }

                /* Initialize IRQ poll */
                if (afu_is_irqpoll_enabled(afu))
                        irq_poll_init(&hwq->irqpoll, afu->irqpoll_weight,
                                      cxlflash_irqpoll);

        }

        rc = init_global(cfg);

        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * init_intr() - setup interrupt handlers for the master context
 * @cfg:        Internal structure associated with the host.
 * @hwq:        Hardware queue to initialize.
 *
 * Return: 0 on success, -errno on failure
 */
static enum undo_level init_intr(struct cxlflash_cfg *cfg,
                                 struct hwq *hwq)
{
        struct device *dev = &cfg->dev->dev;
        struct cxl_context *ctx = hwq->ctx;
        int rc = 0;
        enum undo_level level = UNDO_NOOP;
        bool is_primary_hwq = (hwq->index == PRIMARY_HWQ);
        int num_irqs = is_primary_hwq ? 3 : 2;

        rc = cxl_allocate_afu_irqs(ctx, num_irqs);
        if (unlikely(rc)) {
                dev_err(dev, "%s: allocate_afu_irqs failed rc=%d\n",
                        __func__, rc);
                level = UNDO_NOOP;
                goto out;
        }

        rc = cxl_map_afu_irq(ctx, 1, cxlflash_sync_err_irq, hwq,
                             "SISL_MSI_SYNC_ERROR");
        if (unlikely(rc <= 0)) {
                dev_err(dev, "%s: SISL_MSI_SYNC_ERROR map failed\n", __func__);
                level = FREE_IRQ;
                goto out;
        }

        rc = cxl_map_afu_irq(ctx, 2, cxlflash_rrq_irq, hwq,
                             "SISL_MSI_RRQ_UPDATED");
        if (unlikely(rc <= 0)) {
                dev_err(dev, "%s: SISL_MSI_RRQ_UPDATED map failed\n", __func__);
                level = UNMAP_ONE;
                goto out;
        }

        /* SISL_MSI_ASYNC_ERROR is setup only for the primary HWQ */
        if (!is_primary_hwq)
                goto out;

        rc = cxl_map_afu_irq(ctx, 3, cxlflash_async_err_irq, hwq,
                             "SISL_MSI_ASYNC_ERROR");
        if (unlikely(rc <= 0)) {
                dev_err(dev, "%s: SISL_MSI_ASYNC_ERROR map failed\n", __func__);
                level = UNMAP_TWO;
                goto out;
        }
out:
        return level;
}

/**
 * init_mc() - create and register as the master context
 * @cfg:        Internal structure associated with the host.
 * index:       HWQ Index of the master context.
 *
 * Return: 0 on success, -errno on failure
 */
static int init_mc(struct cxlflash_cfg *cfg, u32 index)
{
        struct cxl_context *ctx;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq = get_hwq(cfg->afu, index);
        int rc = 0;
        enum undo_level level;

        hwq->afu = cfg->afu;
        hwq->index = index;
        INIT_LIST_HEAD(&hwq->pending_cmds);

        if (index == PRIMARY_HWQ)
                ctx = cxl_get_context(cfg->dev);
        else
                ctx = cxl_dev_context_init(cfg->dev);
        if (unlikely(!ctx)) {
                rc = -ENOMEM;
                goto err1;
        }

        WARN_ON(hwq->ctx);
        hwq->ctx = ctx;

        /* Set it up as a master with the CXL */
        cxl_set_master(ctx);

        /* Reset AFU when initializing primary context */
        if (index == PRIMARY_HWQ) {
                rc = cxl_afu_reset(ctx);
                if (unlikely(rc)) {
                        dev_err(dev, "%s: AFU reset failed rc=%d\n",
                                      __func__, rc);
                        goto err1;
                }
        }

        level = init_intr(cfg, hwq);
        if (unlikely(level)) {
                dev_err(dev, "%s: interrupt init failed rc=%d\n", __func__, rc);
                goto err2;
        }

        /* This performs the equivalent of the CXL_IOCTL_START_WORK.
         * The CXL_IOCTL_GET_PROCESS_ELEMENT is implicit in the process
         * element (pe) that is embedded in the context (ctx)
         */
        rc = start_context(cfg, index);
        if (unlikely(rc)) {
                dev_err(dev, "%s: start context failed rc=%d\n", __func__, rc);
                level = UNMAP_THREE;
                goto err2;
        }

out:
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
err2:
        term_intr(cfg, level, index);
        if (index != PRIMARY_HWQ)
                cxl_release_context(ctx);
err1:
        hwq->ctx = NULL;
        goto out;
}

/**
 * get_num_afu_ports() - determines and configures the number of AFU ports
 * @cfg:        Internal structure associated with the host.
 *
 * This routine determines the number of AFU ports by converting the global
 * port selection mask. The converted value is only valid following an AFU
 * reset (explicit or power-on). This routine must be invoked shortly after
 * mapping as other routines are dependent on the number of ports during the
 * initialization sequence.
 *
 * To support legacy AFUs that might not have reflected an initial global
 * port mask (value read is 0), default to the number of ports originally
 * supported by the cxlflash driver (2) before hardware with other port
 * offerings was introduced.
 */
static void get_num_afu_ports(struct cxlflash_cfg *cfg)
{
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        u64 port_mask;
        int num_fc_ports = LEGACY_FC_PORTS;

        port_mask = readq_be(&afu->afu_map->global.regs.afu_port_sel);
        if (port_mask != 0ULL)
                num_fc_ports = min(ilog2(port_mask) + 1, MAX_FC_PORTS);

        dev_dbg(dev, "%s: port_mask=%016llx num_fc_ports=%d\n",
                __func__, port_mask, num_fc_ports);

        cfg->num_fc_ports = num_fc_ports;
        cfg->host->max_channel = PORTNUM2CHAN(num_fc_ports);
}

/**
 * init_afu() - setup as master context and start AFU
 * @cfg:        Internal structure associated with the host.
 *
 * This routine is a higher level of control for configuring the
 * AFU on probe and reset paths.
 *
 * Return: 0 on success, -errno on failure
 */
static int init_afu(struct cxlflash_cfg *cfg)
{
        u64 reg;
        int rc = 0;
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct hwq *hwq;
        int i;

        cxl_perst_reloads_same_image(cfg->cxl_afu, true);

        afu->num_hwqs = afu->desired_hwqs;
        for (i = 0; i < afu->num_hwqs; i++) {
                rc = init_mc(cfg, i);
                if (rc) {
                        dev_err(dev, "%s: init_mc failed rc=%d index=%d\n",
                                __func__, rc, i);
                        goto err1;
                }
        }

        /* Map the entire MMIO space of the AFU using the first context */
        hwq = get_hwq(afu, PRIMARY_HWQ);
        afu->afu_map = cxl_psa_map(hwq->ctx);
        if (!afu->afu_map) {
                dev_err(dev, "%s: cxl_psa_map failed\n", __func__);
                rc = -ENOMEM;
                goto err1;
        }

        /* No byte reverse on reading afu_version or string will be backwards */
        reg = readq(&afu->afu_map->global.regs.afu_version);
        memcpy(afu->version, &reg, sizeof(reg));
        afu->interface_version =
            readq_be(&afu->afu_map->global.regs.interface_version);
        if ((afu->interface_version + 1) == 0) {
                dev_err(dev, "Back level AFU, please upgrade. AFU version %s "
                        "interface version %016llx\n", afu->version,
                       afu->interface_version);
                rc = -EINVAL;
                goto err1;
        }

        if (afu_is_sq_cmd_mode(afu)) {
                afu->send_cmd = send_cmd_sq;
                afu->context_reset = context_reset_sq;
        } else {
                afu->send_cmd = send_cmd_ioarrin;
                afu->context_reset = context_reset_ioarrin;
        }

        dev_dbg(dev, "%s: afu_ver=%s interface_ver=%016llx\n", __func__,
                afu->version, afu->interface_version);

        get_num_afu_ports(cfg);

        rc = start_afu(cfg);
        if (rc) {
                dev_err(dev, "%s: start_afu failed, rc=%d\n", __func__, rc);
                goto err1;
        }

        afu_err_intr_init(cfg->afu);
        for (i = 0; i < afu->num_hwqs; i++) {
                hwq = get_hwq(afu, i);

                hwq->room = readq_be(&hwq->host_map->cmd_room);
        }

        /* Restore the LUN mappings */
        cxlflash_restore_luntable(cfg);
out:
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;

err1:
        for (i = afu->num_hwqs - 1; i >= 0; i--) {
                term_intr(cfg, UNMAP_THREE, i);
                term_mc(cfg, i);
        }
        goto out;
}

/**
 * afu_reset() - resets the AFU
 * @cfg:        Internal structure associated with the host.
 *
 * Return: 0 on success, -errno on failure
 */
static int afu_reset(struct cxlflash_cfg *cfg)
{
        struct device *dev = &cfg->dev->dev;
        int rc = 0;

        /* Stop the context before the reset. Since the context is
         * no longer available restart it after the reset is complete
         */
        term_afu(cfg);

        rc = init_afu(cfg);

        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * drain_ioctls() - wait until all currently executing ioctls have completed
 * @cfg:        Internal structure associated with the host.
 *
 * Obtain write access to read/write semaphore that wraps ioctl
 * handling to 'drain' ioctls currently executing.
 */
static void drain_ioctls(struct cxlflash_cfg *cfg)
{
        down_write(&cfg->ioctl_rwsem);
        up_write(&cfg->ioctl_rwsem);
}

/**
 * cxlflash_async_reset_host() - asynchronous host reset handler
 * @data:       Private data provided while scheduling reset.
 * @cookie:     Cookie that can be used for checkpointing.
 */
static void cxlflash_async_reset_host(void *data, async_cookie_t cookie)
{
        struct cxlflash_cfg *cfg = data;
        struct device *dev = &cfg->dev->dev;
        int rc = 0;

        if (cfg->state != STATE_RESET) {
                dev_dbg(dev, "%s: Not performing a reset, state=%d\n",
                        __func__, cfg->state);
                goto out;
        }

        drain_ioctls(cfg);
        cxlflash_mark_contexts_error(cfg);
        rc = afu_reset(cfg);
        if (rc)
                cfg->state = STATE_FAILTERM;
        else
                cfg->state = STATE_NORMAL;
        wake_up_all(&cfg->reset_waitq);

out:
        scsi_unblock_requests(cfg->host);
}

/**
 * cxlflash_schedule_async_reset() - schedule an asynchronous host reset
 * @cfg:        Internal structure associated with the host.
 */
static void cxlflash_schedule_async_reset(struct cxlflash_cfg *cfg)
{
        struct device *dev = &cfg->dev->dev;

        if (cfg->state != STATE_NORMAL) {
                dev_dbg(dev, "%s: Not performing reset state=%d\n",
                        __func__, cfg->state);
                return;
        }

        cfg->state = STATE_RESET;
        scsi_block_requests(cfg->host);
        cfg->async_reset_cookie = async_schedule(cxlflash_async_reset_host,
                                                 cfg);
}

/**
 * send_afu_cmd() - builds and sends an internal AFU command
 * @afu:        AFU associated with the host.
 * @rcb:        Pre-populated IOARCB describing command to send.
 *
 * The AFU can only take one internal AFU command at a time. This limitation is
 * enforced by using a mutex to provide exclusive access to the AFU during the
 * operation. This design point requires calling threads to not be on interrupt
 * context due to the possibility of sleeping during concurrent AFU operations.
 *
 * The command status is optionally passed back to the caller when the caller
 * populates the IOASA field of the IOARCB with a pointer to an IOASA structure.
 *
 * Return:
 *      0 on success, -errno on failure
 */
static int send_afu_cmd(struct afu *afu, struct sisl_ioarcb *rcb)
{
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;
        struct afu_cmd *cmd = NULL;
        struct hwq *hwq = get_hwq(afu, PRIMARY_HWQ);
        char *buf = NULL;
        int rc = 0;
        int nretry = 0;
        static DEFINE_MUTEX(sync_active);

        if (cfg->state != STATE_NORMAL) {
                dev_dbg(dev, "%s: Sync not required state=%u\n",
                        __func__, cfg->state);
                return 0;
        }

        mutex_lock(&sync_active);
        atomic_inc(&afu->cmds_active);
        buf = kmalloc(sizeof(*cmd) + __alignof__(*cmd) - 1, GFP_KERNEL);
        if (unlikely(!buf)) {
                dev_err(dev, "%s: no memory for command\n", __func__);
                rc = -ENOMEM;
                goto out;
        }

        cmd = (struct afu_cmd *)PTR_ALIGN(buf, __alignof__(*cmd));

retry:
        memset(cmd, 0, sizeof(*cmd));
        memcpy(&cmd->rcb, rcb, sizeof(*rcb));
        INIT_LIST_HEAD(&cmd->queue);
        init_completion(&cmd->cevent);
        cmd->parent = afu;
        cmd->hwq_index = hwq->index;
        cmd->rcb.ctx_id = hwq->ctx_hndl;

        dev_dbg(dev, "%s: afu=%p cmd=%p type=%02x nretry=%d\n",
                __func__, afu, cmd, cmd->rcb.cdb[0], nretry);

        rc = afu->send_cmd(afu, cmd);
        if (unlikely(rc)) {
                rc = -ENOBUFS;
                goto out;
        }

        rc = wait_resp(afu, cmd);
        switch (rc) {
        case -ETIMEDOUT:
                rc = afu->context_reset(hwq);
                if (rc) {
                        cxlflash_schedule_async_reset(cfg);
                        break;
                }
                /* fall through to retry */
        case -EAGAIN:
                if (++nretry < 2)
                        goto retry;
                /* fall through to exit */
        default:
                break;
        }

        if (rcb->ioasa)
                *rcb->ioasa = cmd->sa;
out:
        atomic_dec(&afu->cmds_active);
        mutex_unlock(&sync_active);
        kfree(buf);
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * cxlflash_afu_sync() - builds and sends an AFU sync command
 * @afu:        AFU associated with the host.
 * @ctx:        Identifies context requesting sync.
 * @res:        Identifies resource requesting sync.
 * @mode:       Type of sync to issue (lightweight, heavyweight, global).
 *
 * AFU sync operations are only necessary and allowed when the device is
 * operating normally. When not operating normally, sync requests can occur as
 * part of cleaning up resources associated with an adapter prior to removal.
 * In this scenario, these requests are simply ignored (safe due to the AFU
 * going away).
 *
 * Return:
 *      0 on success, -errno on failure
 */
int cxlflash_afu_sync(struct afu *afu, ctx_hndl_t ctx, res_hndl_t res, u8 mode)
{
        struct cxlflash_cfg *cfg = afu->parent;
        struct device *dev = &cfg->dev->dev;
        struct sisl_ioarcb rcb = { 0 };

        dev_dbg(dev, "%s: afu=%p ctx=%u res=%u mode=%u\n",
                __func__, afu, ctx, res, mode);

        rcb.req_flags = SISL_REQ_FLAGS_AFU_CMD;
        rcb.msi = SISL_MSI_RRQ_UPDATED;
        rcb.timeout = MC_AFU_SYNC_TIMEOUT;

        rcb.cdb[0] = SISL_AFU_CMD_SYNC;
        rcb.cdb[1] = mode;
        put_unaligned_be16(ctx, &rcb.cdb[2]);
        put_unaligned_be32(res, &rcb.cdb[4]);

        return send_afu_cmd(afu, &rcb);
}

/**
 * cxlflash_eh_abort_handler() - abort a SCSI command
 * @scp:        SCSI command to abort.
 *
 * CXL Flash devices do not support a single command abort. Reset the context
 * as per SISLite specification. Flush any pending commands in the hardware
 * queue before the reset.
 *
 * Return: SUCCESS/FAILED as defined in scsi/scsi.h
 */
static int cxlflash_eh_abort_handler(struct scsi_cmnd *scp)
{
        int rc = FAILED;
        struct Scsi_Host *host = scp->device->host;
        struct cxlflash_cfg *cfg = shost_priv(host);
        struct afu_cmd *cmd = sc_to_afuc(scp);
        struct device *dev = &cfg->dev->dev;
        struct afu *afu = cfg->afu;
        struct hwq *hwq = get_hwq(afu, cmd->hwq_index);

        dev_dbg(dev, "%s: (scp=%p) %d/%d/%d/%llu "
                "cdb=(%08x-%08x-%08x-%08x)\n", __func__, scp, host->host_no,
                scp->device->channel, scp->device->id, scp->device->lun,
                get_unaligned_be32(&((u32 *)scp->cmnd)[0]),
                get_unaligned_be32(&((u32 *)scp->cmnd)[1]),
                get_unaligned_be32(&((u32 *)scp->cmnd)[2]),
                get_unaligned_be32(&((u32 *)scp->cmnd)[3]));

        /* When the state is not normal, another reset/reload is in progress.
         * Return failed and the mid-layer will invoke host reset handler.
         */
        if (cfg->state != STATE_NORMAL) {
                dev_dbg(dev, "%s: Invalid state for abort, state=%d\n",
                        __func__, cfg->state);
                goto out;
        }

        rc = afu->context_reset(hwq);
        if (unlikely(rc))
                goto out;

        rc = SUCCESS;

out:
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * cxlflash_eh_device_reset_handler() - reset a single LUN
 * @scp:        SCSI command to send.
 *
 * Return:
 *      SUCCESS as defined in scsi/scsi.h
 *      FAILED as defined in scsi/scsi.h
 */
static int cxlflash_eh_device_reset_handler(struct scsi_cmnd *scp)
{
        int rc = SUCCESS;
        struct scsi_device *sdev = scp->device;
        struct Scsi_Host *host = sdev->host;
        struct cxlflash_cfg *cfg = shost_priv(host);
        struct device *dev = &cfg->dev->dev;
        int rcr = 0;

        dev_dbg(dev, "%s: %d/%d/%d/%llu\n", __func__,
                host->host_no, sdev->channel, sdev->id, sdev->lun);
retry:
        switch (cfg->state) {
        case STATE_NORMAL:
                rcr = send_tmf(cfg, sdev, TMF_LUN_RESET);
                if (unlikely(rcr))
                        rc = FAILED;
                break;
        case STATE_RESET:
                wait_event(cfg->reset_waitq, cfg->state != STATE_RESET);
                goto retry;
        default:
                rc = FAILED;
                break;
        }

        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * cxlflash_eh_host_reset_handler() - reset the host adapter
 * @scp:        SCSI command from stack identifying host.
 *
 * Following a reset, the state is evaluated again in case an EEH occurred
 * during the reset. In such a scenario, the host reset will either yield
 * until the EEH recovery is complete or return success or failure based
 * upon the current device state.
 *
 * Return:
 *      SUCCESS as defined in scsi/scsi.h
 *      FAILED as defined in scsi/scsi.h
 */
static int cxlflash_eh_host_reset_handler(struct scsi_cmnd *scp)
{
        int rc = SUCCESS;
        int rcr = 0;
        struct Scsi_Host *host = scp->device->host;
        struct cxlflash_cfg *cfg = shost_priv(host);
        struct device *dev = &cfg->dev->dev;

        dev_dbg(dev, "%s: %d\n", __func__, host->host_no);

        switch (cfg->state) {
        case STATE_NORMAL:
                cfg->state = STATE_RESET;
                drain_ioctls(cfg);
                cxlflash_mark_contexts_error(cfg);
                rcr = afu_reset(cfg);
                if (rcr) {
                        rc = FAILED;
                        cfg->state = STATE_FAILTERM;
                } else
                        cfg->state = STATE_NORMAL;
                wake_up_all(&cfg->reset_waitq);
                ssleep(1);
                /* fall through */
        case STATE_RESET:
                wait_event(cfg->reset_waitq, cfg->state != STATE_RESET);
                if (cfg->state == STATE_NORMAL)
                        break;
                /* fall through */
        default:
                rc = FAILED;
                break;
        }

        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * cxlflash_change_queue_depth() - change the queue depth for the device
 * @sdev:       SCSI device destined for queue depth change.
 * @qdepth:     Requested queue depth value to set.
 *
 * The requested queue depth is capped to the maximum supported value.
 *
 * Return: The actual queue depth set.
 */
static int cxlflash_change_queue_depth(struct scsi_device *sdev, int qdepth)
{

        if (qdepth > CXLFLASH_MAX_CMDS_PER_LUN)
                qdepth = CXLFLASH_MAX_CMDS_PER_LUN;

        scsi_change_queue_depth(sdev, qdepth);
        return sdev->queue_depth;
}

/**
 * cxlflash_show_port_status() - queries and presents the current port status
 * @port:       Desired port for status reporting.
 * @cfg:        Internal structure associated with the host.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf or -EINVAL.
 */
static ssize_t cxlflash_show_port_status(u32 port,
                                         struct cxlflash_cfg *cfg,
                                         char *buf)
{
        struct device *dev = &cfg->dev->dev;
        char *disp_status;
        u64 status;
        __be64 __iomem *fc_port_regs;

        WARN_ON(port >= MAX_FC_PORTS);

        if (port >= cfg->num_fc_ports) {
                dev_info(dev, "%s: Port %d not supported on this card.\n",
                        __func__, port);
                return -EINVAL;
        }

        fc_port_regs = get_fc_port_regs(cfg, port);
        status = readq_be(&fc_port_regs[FC_MTIP_STATUS / 8]);
        status &= FC_MTIP_STATUS_MASK;

        if (status == FC_MTIP_STATUS_ONLINE)
                disp_status = "online";
        else if (status == FC_MTIP_STATUS_OFFLINE)
                disp_status = "offline";
        else
                disp_status = "unknown";

        return scnprintf(buf, PAGE_SIZE, "%s\n", disp_status);
}

/**
 * port0_show() - queries and presents the current status of port 0
 * @dev:        Generic device associated with the host owning the port.
 * @attr:       Device attribute representing the port.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t port0_show(struct device *dev,
                          struct device_attribute *attr,
                          char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));

        return cxlflash_show_port_status(0, cfg, buf);
}

/**
 * port1_show() - queries and presents the current status of port 1
 * @dev:        Generic device associated with the host owning the port.
 * @attr:       Device attribute representing the port.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t port1_show(struct device *dev,
                          struct device_attribute *attr,
                          char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));

        return cxlflash_show_port_status(1, cfg, buf);
}

/**
 * port2_show() - queries and presents the current status of port 2
 * @dev:        Generic device associated with the host owning the port.
 * @attr:       Device attribute representing the port.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t port2_show(struct device *dev,
                          struct device_attribute *attr,
                          char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));

        return cxlflash_show_port_status(2, cfg, buf);
}

/**
 * port3_show() - queries and presents the current status of port 3
 * @dev:        Generic device associated with the host owning the port.
 * @attr:       Device attribute representing the port.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t port3_show(struct device *dev,
                          struct device_attribute *attr,
                          char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));

        return cxlflash_show_port_status(3, cfg, buf);
}

/**
 * lun_mode_show() - presents the current LUN mode of the host
 * @dev:        Generic device associated with the host.
 * @attr:       Device attribute representing the LUN mode.
 * @buf:        Buffer of length PAGE_SIZE to report back the LUN mode in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t lun_mode_show(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));
        struct afu *afu = cfg->afu;

        return scnprintf(buf, PAGE_SIZE, "%u\n", afu->internal_lun);
}

/**
 * lun_mode_store() - sets the LUN mode of the host
 * @dev:        Generic device associated with the host.
 * @attr:       Device attribute representing the LUN mode.
 * @buf:        Buffer of length PAGE_SIZE containing the LUN mode in ASCII.
 * @count:      Length of data resizing in @buf.
 *
 * The CXL Flash AFU supports a dummy LUN mode where the external
 * links and storage are not required. Space on the FPGA is used
 * to create 1 or 2 small LUNs which are presented to the system
 * as if they were a normal storage device. This feature is useful
 * during development and also provides manufacturing with a way
 * to test the AFU without an actual device.
 *
 * 0 = external LUN[s] (default)
 * 1 = internal LUN (1 x 64K, 512B blocks, id 0)
 * 2 = internal LUN (1 x 64K, 4K blocks, id 0)
 * 3 = internal LUN (2 x 32K, 512B blocks, ids 0,1)
 * 4 = internal LUN (2 x 32K, 4K blocks, ids 0,1)
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t lun_mode_store(struct device *dev,
                              struct device_attribute *attr,
                              const char *buf, size_t count)
{
        struct Scsi_Host *shost = class_to_shost(dev);
        struct cxlflash_cfg *cfg = shost_priv(shost);
        struct afu *afu = cfg->afu;
        int rc;
        u32 lun_mode;

        rc = kstrtouint(buf, 10, &lun_mode);
        if (!rc && (lun_mode < 5) && (lun_mode != afu->internal_lun)) {
                afu->internal_lun = lun_mode;

                /*
                 * When configured for internal LUN, there is only one channel,
                 * channel number 0, else there will be one less than the number
                 * of fc ports for this card.
                 */
                if (afu->internal_lun)
                        shost->max_channel = 0;
                else
                        shost->max_channel = PORTNUM2CHAN(cfg->num_fc_ports);

                afu_reset(cfg);
                scsi_scan_host(cfg->host);
        }

        return count;
}

/**
 * ioctl_version_show() - presents the current ioctl version of the host
 * @dev:        Generic device associated with the host.
 * @attr:       Device attribute representing the ioctl version.
 * @buf:        Buffer of length PAGE_SIZE to report back the ioctl version.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t ioctl_version_show(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        ssize_t bytes = 0;

        bytes = scnprintf(buf, PAGE_SIZE,
                          "disk: %u\n", DK_CXLFLASH_VERSION_0);
        bytes += scnprintf(buf + bytes, PAGE_SIZE - bytes,
                           "host: %u\n", HT_CXLFLASH_VERSION_0);

        return bytes;
}

/**
 * cxlflash_show_port_lun_table() - queries and presents the port LUN table
 * @port:       Desired port for status reporting.
 * @cfg:        Internal structure associated with the host.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf or -EINVAL.
 */
static ssize_t cxlflash_show_port_lun_table(u32 port,
                                            struct cxlflash_cfg *cfg,
                                            char *buf)
{
        struct device *dev = &cfg->dev->dev;
        __be64 __iomem *fc_port_luns;
        int i;
        ssize_t bytes = 0;

        WARN_ON(port >= MAX_FC_PORTS);

        if (port >= cfg->num_fc_ports) {
                dev_info(dev, "%s: Port %d not supported on this card.\n",
                        __func__, port);
                return -EINVAL;
        }

        fc_port_luns = get_fc_port_luns(cfg, port);

        for (i = 0; i < CXLFLASH_NUM_VLUNS; i++)
                bytes += scnprintf(buf + bytes, PAGE_SIZE - bytes,
                                   "%03d: %016llx\n",
                                   i, readq_be(&fc_port_luns[i]));
        return bytes;
}

/**
 * port0_lun_table_show() - presents the current LUN table of port 0
 * @dev:        Generic device associated with the host owning the port.
 * @attr:       Device attribute representing the port.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t port0_lun_table_show(struct device *dev,
                                    struct device_attribute *attr,
                                    char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));

        return cxlflash_show_port_lun_table(0, cfg, buf);
}

/**
 * port1_lun_table_show() - presents the current LUN table of port 1
 * @dev:        Generic device associated with the host owning the port.
 * @attr:       Device attribute representing the port.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t port1_lun_table_show(struct device *dev,
                                    struct device_attribute *attr,
                                    char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));

        return cxlflash_show_port_lun_table(1, cfg, buf);
}

/**
 * port2_lun_table_show() - presents the current LUN table of port 2
 * @dev:        Generic device associated with the host owning the port.
 * @attr:       Device attribute representing the port.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t port2_lun_table_show(struct device *dev,
                                    struct device_attribute *attr,
                                    char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));

        return cxlflash_show_port_lun_table(2, cfg, buf);
}

/**
 * port3_lun_table_show() - presents the current LUN table of port 3
 * @dev:        Generic device associated with the host owning the port.
 * @attr:       Device attribute representing the port.
 * @buf:        Buffer of length PAGE_SIZE to report back port status in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t port3_lun_table_show(struct device *dev,
                                    struct device_attribute *attr,
                                    char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));

        return cxlflash_show_port_lun_table(3, cfg, buf);
}

/**
 * irqpoll_weight_show() - presents the current IRQ poll weight for the host
 * @dev:        Generic device associated with the host.
 * @attr:       Device attribute representing the IRQ poll weight.
 * @buf:        Buffer of length PAGE_SIZE to report back the current IRQ poll
 *              weight in ASCII.
 *
 * An IRQ poll weight of 0 indicates polling is disabled.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t irqpoll_weight_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));
        struct afu *afu = cfg->afu;

        return scnprintf(buf, PAGE_SIZE, "%u\n", afu->irqpoll_weight);
}

/**
 * irqpoll_weight_store() - sets the current IRQ poll weight for the host
 * @dev:        Generic device associated with the host.
 * @attr:       Device attribute representing the IRQ poll weight.
 * @buf:        Buffer of length PAGE_SIZE containing the desired IRQ poll
 *              weight in ASCII.
 * @count:      Length of data resizing in @buf.
 *
 * An IRQ poll weight of 0 indicates polling is disabled.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t irqpoll_weight_store(struct device *dev,
                                    struct device_attribute *attr,
                                    const char *buf, size_t count)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));
        struct device *cfgdev = &cfg->dev->dev;
        struct afu *afu = cfg->afu;
        struct hwq *hwq;
        u32 weight;
        int rc, i;

        rc = kstrtouint(buf, 10, &weight);
        if (rc)
                return -EINVAL;

        if (weight > 256) {
                dev_info(cfgdev,
                         "Invalid IRQ poll weight. It must be 256 or less.\n");
                return -EINVAL;
        }

        if (weight == afu->irqpoll_weight) {
                dev_info(cfgdev,
                         "Current IRQ poll weight has the same weight.\n");
                return -EINVAL;
        }

        if (afu_is_irqpoll_enabled(afu)) {
                for (i = 0; i < afu->num_hwqs; i++) {
                        hwq = get_hwq(afu, i);

                        irq_poll_disable(&hwq->irqpoll);
                }
        }

        afu->irqpoll_weight = weight;

        if (weight > 0) {
                for (i = 0; i < afu->num_hwqs; i++) {
                        hwq = get_hwq(afu, i);

                        irq_poll_init(&hwq->irqpoll, weight, cxlflash_irqpoll);
                }
        }

        return count;
}

/**
 * num_hwqs_show() - presents the number of hardware queues for the host
 * @dev:        Generic device associated with the host.
 * @attr:       Device attribute representing the number of hardware queues.
 * @buf:        Buffer of length PAGE_SIZE to report back the number of hardware
 *              queues in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t num_hwqs_show(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));
        struct afu *afu = cfg->afu;

        return scnprintf(buf, PAGE_SIZE, "%u\n", afu->num_hwqs);
}

/**
 * num_hwqs_store() - sets the number of hardware queues for the host
 * @dev:        Generic device associated with the host.
 * @attr:       Device attribute representing the number of hardware queues.
 * @buf:        Buffer of length PAGE_SIZE containing the number of hardware
 *              queues in ASCII.
 * @count:      Length of data resizing in @buf.
 *
 * n > 0: num_hwqs = n
 * n = 0: num_hwqs = num_online_cpus()
 * n < 0: num_online_cpus() / abs(n)
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t num_hwqs_store(struct device *dev,
                              struct device_attribute *attr,
                              const char *buf, size_t count)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));
        struct afu *afu = cfg->afu;
        int rc;
        int nhwqs, num_hwqs;

        rc = kstrtoint(buf, 10, &nhwqs);
        if (rc)
                return -EINVAL;

        if (nhwqs >= 1)
                num_hwqs = nhwqs;
        else if (nhwqs == 0)
                num_hwqs = num_online_cpus();
        else
                num_hwqs = num_online_cpus() / abs(nhwqs);

        afu->desired_hwqs = min(num_hwqs, CXLFLASH_MAX_HWQS);
        WARN_ON_ONCE(afu->desired_hwqs == 0);

retry:
        switch (cfg->state) {
        case STATE_NORMAL:
                cfg->state = STATE_RESET;
                drain_ioctls(cfg);
                cxlflash_mark_contexts_error(cfg);
                rc = afu_reset(cfg);
                if (rc)
                        cfg->state = STATE_FAILTERM;
                else
                        cfg->state = STATE_NORMAL;
                wake_up_all(&cfg->reset_waitq);
                break;
        case STATE_RESET:
                wait_event(cfg->reset_waitq, cfg->state != STATE_RESET);
                if (cfg->state == STATE_NORMAL)
                        goto retry;
        default:
                /* Ideally should not happen */
                dev_err(dev, "%s: Device is not ready, state=%d\n",
                        __func__, cfg->state);
                break;
        }

        return count;
}

static const char *hwq_mode_name[MAX_HWQ_MODE] = { "rr", "tag", "cpu" };

/**
 * hwq_mode_show() - presents the HWQ steering mode for the host
 * @dev:        Generic device associated with the host.
 * @attr:       Device attribute representing the HWQ steering mode.
 * @buf:        Buffer of length PAGE_SIZE to report back the HWQ steering mode
 *              as a character string.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t hwq_mode_show(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        struct cxlflash_cfg *cfg = shost_priv(class_to_shost(dev));
        struct afu *afu = cfg->afu;

        return scnprintf(buf, PAGE_SIZE, "%s\n", hwq_mode_name[afu->hwq_mode]);
}

/**
 * hwq_mode_store() - sets the HWQ steering mode for the host
 * @dev:        Generic device associated with the host.
 * @attr:       Device attribute representing the HWQ steering mode.
 * @buf:        Buffer of length PAGE_SIZE containing the HWQ steering mode
 *              as a character string.
 * @count:      Length of data resizing in @buf.
 *
 * rr = Round-Robin
 * tag = Block MQ Tagging
 * cpu = CPU Affinity
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t hwq_mode_store(struct device *dev,
                              struct device_attribute *attr,
                              const char *buf, size_t count)
{
        struct Scsi_Host *shost = class_to_shost(dev);
        struct cxlflash_cfg *cfg = shost_priv(shost);
        struct device *cfgdev = &cfg->dev->dev;
        struct afu *afu = cfg->afu;
        int i;
        u32 mode = MAX_HWQ_MODE;

        for (i = 0; i < MAX_HWQ_MODE; i++) {
                if (!strncmp(hwq_mode_name[i], buf, strlen(hwq_mode_name[i]))) {
                        mode = i;
                        break;
                }
        }

        if (mode >= MAX_HWQ_MODE) {
                dev_info(cfgdev, "Invalid HWQ steering mode.\n");
                return -EINVAL;
        }

        if ((mode == HWQ_MODE_TAG) && !shost_use_blk_mq(shost)) {
                dev_info(cfgdev, "SCSI-MQ is not enabled, use a different "
                         "HWQ steering mode.\n");
                return -EINVAL;
        }

        afu->hwq_mode = mode;

        return count;
}

/**
 * mode_show() - presents the current mode of the device
 * @dev:        Generic device associated with the device.
 * @attr:       Device attribute representing the device mode.
 * @buf:        Buffer of length PAGE_SIZE to report back the dev mode in ASCII.
 *
 * Return: The size of the ASCII string returned in @buf.
 */
static ssize_t mode_show(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
        struct scsi_device *sdev = to_scsi_device(dev);

        return scnprintf(buf, PAGE_SIZE, "%s\n",
                         sdev->hostdata ? "superpipe" : "legacy");
}

/*
 * Host attributes
 */
static DEVICE_ATTR_RO(port0);
static DEVICE_ATTR_RO(port1);
static DEVICE_ATTR_RO(port2);
static DEVICE_ATTR_RO(port3);
static DEVICE_ATTR_RW(lun_mode);
static DEVICE_ATTR_RO(ioctl_version);
static DEVICE_ATTR_RO(port0_lun_table);
static DEVICE_ATTR_RO(port1_lun_table);
static DEVICE_ATTR_RO(port2_lun_table);
static DEVICE_ATTR_RO(port3_lun_table);
static DEVICE_ATTR_RW(irqpoll_weight);
static DEVICE_ATTR_RW(num_hwqs);
static DEVICE_ATTR_RW(hwq_mode);

static struct device_attribute *cxlflash_host_attrs[] = {
        &dev_attr_port0,
        &dev_attr_port1,
        &dev_attr_port2,
        &dev_attr_port3,
        &dev_attr_lun_mode,
        &dev_attr_ioctl_version,
        &dev_attr_port0_lun_table,
        &dev_attr_port1_lun_table,
        &dev_attr_port2_lun_table,
        &dev_attr_port3_lun_table,
        &dev_attr_irqpoll_weight,
        &dev_attr_num_hwqs,
        &dev_attr_hwq_mode,
        NULL
};

/*
 * Device attributes
 */
static DEVICE_ATTR_RO(mode);

static struct device_attribute *cxlflash_dev_attrs[] = {
        &dev_attr_mode,
        NULL
};

/*
 * Host template
 */
static struct scsi_host_template driver_template = {
        .module = THIS_MODULE,
        .name = CXLFLASH_ADAPTER_NAME,
        .info = cxlflash_driver_info,
        .ioctl = cxlflash_ioctl,
        .proc_name = CXLFLASH_NAME,
        .queuecommand = cxlflash_queuecommand,
        .eh_abort_handler = cxlflash_eh_abort_handler,
        .eh_device_reset_handler = cxlflash_eh_device_reset_handler,
        .eh_host_reset_handler = cxlflash_eh_host_reset_handler,
        .change_queue_depth = cxlflash_change_queue_depth,
        .cmd_per_lun = CXLFLASH_MAX_CMDS_PER_LUN,
        .can_queue = CXLFLASH_MAX_CMDS,
        .cmd_size = sizeof(struct afu_cmd) + __alignof__(struct afu_cmd) - 1,
        .this_id = -1,
        .sg_tablesize = 1,      /* No scatter gather support */
        .max_sectors = CXLFLASH_MAX_SECTORS,
        .use_clustering = ENABLE_CLUSTERING,
        .shost_attrs = cxlflash_host_attrs,
        .sdev_attrs = cxlflash_dev_attrs,
};

/*
 * Device dependent values
 */
static struct dev_dependent_vals dev_corsa_vals = { CXLFLASH_MAX_SECTORS,
                                        0ULL };
static struct dev_dependent_vals dev_flash_gt_vals = { CXLFLASH_MAX_SECTORS,
                                        CXLFLASH_NOTIFY_SHUTDOWN };
static struct dev_dependent_vals dev_briard_vals = { CXLFLASH_MAX_SECTORS,
                                        CXLFLASH_NOTIFY_SHUTDOWN };

/*
 * PCI device binding table
 */
static struct pci_device_id cxlflash_pci_table[] = {
        {PCI_VENDOR_ID_IBM, PCI_DEVICE_ID_IBM_CORSA,
         PCI_ANY_ID, PCI_ANY_ID, 0, 0, (kernel_ulong_t)&dev_corsa_vals},
        {PCI_VENDOR_ID_IBM, PCI_DEVICE_ID_IBM_FLASH_GT,
         PCI_ANY_ID, PCI_ANY_ID, 0, 0, (kernel_ulong_t)&dev_flash_gt_vals},
        {PCI_VENDOR_ID_IBM, PCI_DEVICE_ID_IBM_BRIARD,
         PCI_ANY_ID, PCI_ANY_ID, 0, 0, (kernel_ulong_t)&dev_briard_vals},
        {}
};

MODULE_DEVICE_TABLE(pci, cxlflash_pci_table);

/**
 * cxlflash_worker_thread() - work thread handler for the AFU
 * @work:       Work structure contained within cxlflash associated with host.
 *
 * Handles the following events:
 * - Link reset which cannot be performed on interrupt context due to
 * blocking up to a few seconds
 * - Rescan the host
 */
static void cxlflash_worker_thread(struct work_struct *work)
{
        struct cxlflash_cfg *cfg = container_of(work, struct cxlflash_cfg,
                                                work_q);
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        __be64 __iomem *fc_port_regs;
        int port;
        ulong lock_flags;

        /* Avoid MMIO if the device has failed */

        if (cfg->state != STATE_NORMAL)
                return;

        spin_lock_irqsave(cfg->host->host_lock, lock_flags);

        if (cfg->lr_state == LINK_RESET_REQUIRED) {
                port = cfg->lr_port;
                if (port < 0)
                        dev_err(dev, "%s: invalid port index %d\n",
                                __func__, port);
                else {
                        spin_unlock_irqrestore(cfg->host->host_lock,
                                               lock_flags);

                        /* The reset can block... */
                        fc_port_regs = get_fc_port_regs(cfg, port);
                        afu_link_reset(afu, port, fc_port_regs);
                        spin_lock_irqsave(cfg->host->host_lock, lock_flags);
                }

                cfg->lr_state = LINK_RESET_COMPLETE;
        }

        spin_unlock_irqrestore(cfg->host->host_lock, lock_flags);

        if (atomic_dec_if_positive(&cfg->scan_host_needed) >= 0)
                scsi_scan_host(cfg->host);
}

/**
 * cxlflash_chr_open() - character device open handler
 * @inode:      Device inode associated with this character device.
 * @file:       File pointer for this device.
 *
 * Only users with admin privileges are allowed to open the character device.
 *
 * Return: 0 on success, -errno on failure
 */
static int cxlflash_chr_open(struct inode *inode, struct file *file)
{
        struct cxlflash_cfg *cfg;

        if (!capable(CAP_SYS_ADMIN))
                return -EACCES;

        cfg = container_of(inode->i_cdev, struct cxlflash_cfg, cdev);
        file->private_data = cfg;

        return 0;
}

/**
 * decode_hioctl() - translates encoded host ioctl to easily identifiable string
 * @cmd:        The host ioctl command to decode.
 *
 * Return: A string identifying the decoded host ioctl.
 */
static char *decode_hioctl(int cmd)
{
        switch (cmd) {
        case HT_CXLFLASH_LUN_PROVISION:
                return __stringify_1(HT_CXLFLASH_LUN_PROVISION);
        }

        return "UNKNOWN";
}

/**
 * cxlflash_lun_provision() - host LUN provisioning handler
 * @cfg:        Internal structure associated with the host.
 * @arg:        Kernel copy of userspace ioctl data structure.
 *
 * Return: 0 on success, -errno on failure
 */
static int cxlflash_lun_provision(struct cxlflash_cfg *cfg,
                                  struct ht_cxlflash_lun_provision *lunprov)
{
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct sisl_ioarcb rcb;
        struct sisl_ioasa asa;
        __be64 __iomem *fc_port_regs;
        u16 port = lunprov->port;
        u16 scmd = lunprov->hdr.subcmd;
        u16 type;
        u64 reg;
        u64 size;
        u64 lun_id;
        int rc = 0;

        if (!afu_is_lun_provision(afu)) {
                rc = -ENOTSUPP;
                goto out;
        }

        if (port >= cfg->num_fc_ports) {
                rc = -EINVAL;
                goto out;
        }

        switch (scmd) {
        case HT_CXLFLASH_LUN_PROVISION_SUBCMD_CREATE_LUN:
                type = SISL_AFU_LUN_PROVISION_CREATE;
                size = lunprov->size;
                lun_id = 0;
                break;
        case HT_CXLFLASH_LUN_PROVISION_SUBCMD_DELETE_LUN:
                type = SISL_AFU_LUN_PROVISION_DELETE;
                size = 0;
                lun_id = lunprov->lun_id;
                break;
        case HT_CXLFLASH_LUN_PROVISION_SUBCMD_QUERY_PORT:
                fc_port_regs = get_fc_port_regs(cfg, port);

                reg = readq_be(&fc_port_regs[FC_MAX_NUM_LUNS / 8]);
                lunprov->max_num_luns = reg;
                reg = readq_be(&fc_port_regs[FC_CUR_NUM_LUNS / 8]);
                lunprov->cur_num_luns = reg;
                reg = readq_be(&fc_port_regs[FC_MAX_CAP_PORT / 8]);
                lunprov->max_cap_port = reg;
                reg = readq_be(&fc_port_regs[FC_CUR_CAP_PORT / 8]);
                lunprov->cur_cap_port = reg;

                goto out;
        default:
                rc = -EINVAL;
                goto out;
        }

        memset(&rcb, 0, sizeof(rcb));
        memset(&asa, 0, sizeof(asa));
        rcb.req_flags = SISL_REQ_FLAGS_AFU_CMD;
        rcb.lun_id = lun_id;
        rcb.msi = SISL_MSI_RRQ_UPDATED;
        rcb.timeout = MC_LUN_PROV_TIMEOUT;
        rcb.ioasa = &asa;

        rcb.cdb[0] = SISL_AFU_CMD_LUN_PROVISION;
        rcb.cdb[1] = type;
        rcb.cdb[2] = port;
        put_unaligned_be64(size, &rcb.cdb[8]);

        rc = send_afu_cmd(afu, &rcb);
        if (rc) {
                dev_err(dev, "%s: send_afu_cmd failed rc=%d asc=%08x afux=%x\n",
                        __func__, rc, asa.ioasc, asa.afu_extra);
                goto out;
        }

        if (scmd == HT_CXLFLASH_LUN_PROVISION_SUBCMD_CREATE_LUN) {
                lunprov->lun_id = (u64)asa.lunid_hi << 32 | asa.lunid_lo;
                memcpy(lunprov->wwid, asa.wwid, sizeof(lunprov->wwid));
        }
out:
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * cxlflash_afu_debug() - host AFU debug handler
 * @cfg:        Internal structure associated with the host.
 * @arg:        Kernel copy of userspace ioctl data structure.
 *
 * For debug requests requiring a data buffer, always provide an aligned
 * (cache line) buffer to the AFU to appease any alignment requirements.
 *
 * Return: 0 on success, -errno on failure
 */
static int cxlflash_afu_debug(struct cxlflash_cfg *cfg,
                              struct ht_cxlflash_afu_debug *afu_dbg)
{
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct sisl_ioarcb rcb;
        struct sisl_ioasa asa;
        char *buf = NULL;
        char *kbuf = NULL;
        void __user *ubuf = (__force void __user *)afu_dbg->data_ea;
        u16 req_flags = SISL_REQ_FLAGS_AFU_CMD;
        u32 ulen = afu_dbg->data_len;
        bool is_write = afu_dbg->hdr.flags & HT_CXLFLASH_HOST_WRITE;
        int rc = 0;

        if (!afu_is_afu_debug(afu)) {
                rc = -ENOTSUPP;
                goto out;
        }

        if (ulen) {
                req_flags |= SISL_REQ_FLAGS_SUP_UNDERRUN;

                if (ulen > HT_CXLFLASH_AFU_DEBUG_MAX_DATA_LEN) {
                        rc = -EINVAL;
                        goto out;
                }

                if (unlikely(!access_ok(is_write ? VERIFY_READ : VERIFY_WRITE,
                                        ubuf, ulen))) {
                        rc = -EFAULT;
                        goto out;
                }

                buf = kmalloc(ulen + cache_line_size() - 1, GFP_KERNEL);
                if (unlikely(!buf)) {
                        rc = -ENOMEM;
                        goto out;
                }

                kbuf = PTR_ALIGN(buf, cache_line_size());

                if (is_write) {
                        req_flags |= SISL_REQ_FLAGS_HOST_WRITE;

                        if (copy_from_user(kbuf, ubuf, ulen)) {
                                rc = -EFAULT;
                                goto out;
                        }
                }
        }

        memset(&rcb, 0, sizeof(rcb));
        memset(&asa, 0, sizeof(asa));

        rcb.req_flags = req_flags;
        rcb.msi = SISL_MSI_RRQ_UPDATED;
        rcb.timeout = MC_AFU_DEBUG_TIMEOUT;
        rcb.ioasa = &asa;

        if (ulen) {
                rcb.data_len = ulen;
                rcb.data_ea = (uintptr_t)kbuf;
        }

        rcb.cdb[0] = SISL_AFU_CMD_DEBUG;
        memcpy(&rcb.cdb[4], afu_dbg->afu_subcmd,
               HT_CXLFLASH_AFU_DEBUG_SUBCMD_LEN);

        rc = send_afu_cmd(afu, &rcb);
        if (rc) {
                dev_err(dev, "%s: send_afu_cmd failed rc=%d asc=%08x afux=%x\n",
                        __func__, rc, asa.ioasc, asa.afu_extra);
                goto out;
        }

        if (ulen && !is_write) {
                if (copy_to_user(ubuf, kbuf, ulen))
                        rc = -EFAULT;
        }
out:
        kfree(buf);
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
}

/**
 * cxlflash_chr_ioctl() - character device IOCTL handler
 * @file:       File pointer for this device.
 * @cmd:        IOCTL command.
 * @arg:        Userspace ioctl data structure.
 *
 * A read/write semaphore is used to implement a 'drain' of currently
 * running ioctls. The read semaphore is taken at the beginning of each
 * ioctl thread and released upon concluding execution. Additionally the
 * semaphore should be released and then reacquired in any ioctl execution
 * path which will wait for an event to occur that is outside the scope of
 * the ioctl (i.e. an adapter reset). To drain the ioctls currently running,
 * a thread simply needs to acquire the write semaphore.
 *
 * Return: 0 on success, -errno on failure
 */
static long cxlflash_chr_ioctl(struct file *file, unsigned int cmd,
                               unsigned long arg)
{
        typedef int (*hioctl) (struct cxlflash_cfg *, void *);

        struct cxlflash_cfg *cfg = file->private_data;
        struct device *dev = &cfg->dev->dev;
        char buf[sizeof(union cxlflash_ht_ioctls)];
        void __user *uarg = (void __user *)arg;
        struct ht_cxlflash_hdr *hdr;
        size_t size = 0;
        bool known_ioctl = false;
        int idx = 0;
        int rc = 0;
        hioctl do_ioctl = NULL;

        static const struct {
                size_t size;
                hioctl ioctl;
        } ioctl_tbl[] = {       /* NOTE: order matters here */
        { sizeof(struct ht_cxlflash_lun_provision),
                (hioctl)cxlflash_lun_provision },
        { sizeof(struct ht_cxlflash_afu_debug),
                (hioctl)cxlflash_afu_debug },
        };

        /* Hold read semaphore so we can drain if needed */
        down_read(&cfg->ioctl_rwsem);

        dev_dbg(dev, "%s: cmd=%u idx=%d tbl_size=%lu\n",
                __func__, cmd, idx, sizeof(ioctl_tbl));

        switch (cmd) {
        case HT_CXLFLASH_LUN_PROVISION:
        case HT_CXLFLASH_AFU_DEBUG:
                known_ioctl = true;
                idx = _IOC_NR(HT_CXLFLASH_LUN_PROVISION) - _IOC_NR(cmd);
                size = ioctl_tbl[idx].size;
                do_ioctl = ioctl_tbl[idx].ioctl;

                if (likely(do_ioctl))
                        break;

                /* fall through */
        default:
                rc = -EINVAL;
                goto out;
        }

        if (unlikely(copy_from_user(&buf, uarg, size))) {
                dev_err(dev, "%s: copy_from_user() fail "
                        "size=%lu cmd=%d (%s) uarg=%p\n",
                        __func__, size, cmd, decode_hioctl(cmd), uarg);
                rc = -EFAULT;
                goto out;
        }

        hdr = (struct ht_cxlflash_hdr *)&buf;
        if (hdr->version != HT_CXLFLASH_VERSION_0) {
                dev_dbg(dev, "%s: Version %u not supported for %s\n",
                        __func__, hdr->version, decode_hioctl(cmd));
                rc = -EINVAL;
                goto out;
        }

        if (hdr->rsvd[0] || hdr->rsvd[1] || hdr->return_flags) {
                dev_dbg(dev, "%s: Reserved/rflags populated\n", __func__);
                rc = -EINVAL;
                goto out;
        }

        rc = do_ioctl(cfg, (void *)&buf);
        if (likely(!rc))
                if (unlikely(copy_to_user(uarg, &buf, size))) {
                        dev_err(dev, "%s: copy_to_user() fail "
                                "size=%lu cmd=%d (%s) uarg=%p\n",
                                __func__, size, cmd, decode_hioctl(cmd), uarg);
                        rc = -EFAULT;
                }

        /* fall through to exit */

out:
        up_read(&cfg->ioctl_rwsem);
        if (unlikely(rc && known_ioctl))
                dev_err(dev, "%s: ioctl %s (%08X) returned rc=%d\n",
                        __func__, decode_hioctl(cmd), cmd, rc);
        else
                dev_dbg(dev, "%s: ioctl %s (%08X) returned rc=%d\n",
                        __func__, decode_hioctl(cmd), cmd, rc);
        return rc;
}

/*
 * Character device file operations
 */
static const struct file_operations cxlflash_chr_fops = {
        .owner          = THIS_MODULE,
        .open           = cxlflash_chr_open,
        .unlocked_ioctl = cxlflash_chr_ioctl,
        .compat_ioctl   = cxlflash_chr_ioctl,
};

/**
 * init_chrdev() - initialize the character device for the host
 * @cfg:        Internal structure associated with the host.
 *
 * Return: 0 on success, -errno on failure
 */
static int init_chrdev(struct cxlflash_cfg *cfg)
{
        struct device *dev = &cfg->dev->dev;
        struct device *char_dev;
        dev_t devno;
        int minor;
        int rc = 0;

        minor = cxlflash_get_minor();
        if (unlikely(minor < 0)) {
                dev_err(dev, "%s: Exhausted allowed adapters\n", __func__);
                rc = -ENOSPC;
                goto out;
        }

        devno = MKDEV(cxlflash_major, minor);
        cdev_init(&cfg->cdev, &cxlflash_chr_fops);

        rc = cdev_add(&cfg->cdev, devno, 1);
        if (rc) {
                dev_err(dev, "%s: cdev_add failed rc=%d\n", __func__, rc);
                goto err1;
        }

        char_dev = device_create(cxlflash_class, NULL, devno,
                                 NULL, "cxlflash%d", minor);
        if (IS_ERR(char_dev)) {
                rc = PTR_ERR(char_dev);
                dev_err(dev, "%s: device_create failed rc=%d\n",
                        __func__, rc);
                goto err2;
        }

        cfg->chardev = char_dev;
out:
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;
err2:
        cdev_del(&cfg->cdev);
err1:
        cxlflash_put_minor(minor);
        goto out;
}

/**
 * cxlflash_probe() - PCI entry point to add host
 * @pdev:       PCI device associated with the host.
 * @dev_id:     PCI device id associated with device.
 *
 * The device will initially start out in a 'probing' state and
 * transition to the 'normal' state at the end of a successful
 * probe. Should an EEH event occur during probe, the notification
 * thread (error_detected()) will wait until the probe handler
 * is nearly complete. At that time, the device will be moved to
 * a 'probed' state and the EEH thread woken up to drive the slot
 * reset and recovery (device moves to 'normal' state). Meanwhile,
 * the probe will be allowed to exit successfully.
 *
 * Return: 0 on success, -errno on failure
 */
static int cxlflash_probe(struct pci_dev *pdev,
                          const struct pci_device_id *dev_id)
{
        struct Scsi_Host *host;
        struct cxlflash_cfg *cfg = NULL;
        struct device *dev = &pdev->dev;
        struct dev_dependent_vals *ddv;
        int rc = 0;
        int k;

        dev_dbg(&pdev->dev, "%s: Found CXLFLASH with IRQ: %d\n",
                __func__, pdev->irq);

        ddv = (struct dev_dependent_vals *)dev_id->driver_data;
        driver_template.max_sectors = ddv->max_sectors;

        host = scsi_host_alloc(&driver_template, sizeof(struct cxlflash_cfg));
        if (!host) {
                dev_err(dev, "%s: scsi_host_alloc failed\n", __func__);
                rc = -ENOMEM;
                goto out;
        }

        host->max_id = CXLFLASH_MAX_NUM_TARGETS_PER_BUS;
        host->max_lun = CXLFLASH_MAX_NUM_LUNS_PER_TARGET;
        host->unique_id = host->host_no;
        host->max_cmd_len = CXLFLASH_MAX_CDB_LEN;

        cfg = shost_priv(host);
        cfg->state = STATE_PROBING;
        cfg->host = host;
        rc = alloc_mem(cfg);
        if (rc) {
                dev_err(dev, "%s: alloc_mem failed\n", __func__);
                rc = -ENOMEM;
                scsi_host_put(cfg->host);
                goto out;
        }

        cfg->init_state = INIT_STATE_NONE;
        cfg->dev = pdev;
        cfg->cxl_fops = cxlflash_cxl_fops;

        /*
         * Promoted LUNs move to the top of the LUN table. The rest stay on
         * the bottom half. The bottom half grows from the end (index = 255),
         * whereas the top half grows from the beginning (index = 0).
         *
         * Initialize the last LUN index for all possible ports.
         */
        cfg->promote_lun_index = 0;

        for (k = 0; k < MAX_FC_PORTS; k++)
                cfg->last_lun_index[k] = CXLFLASH_NUM_VLUNS/2 - 1;

        cfg->dev_id = (struct pci_device_id *)dev_id;

        init_waitqueue_head(&cfg->tmf_waitq);
        init_waitqueue_head(&cfg->reset_waitq);

        INIT_WORK(&cfg->work_q, cxlflash_worker_thread);
        cfg->lr_state = LINK_RESET_INVALID;
        cfg->lr_port = -1;
        spin_lock_init(&cfg->tmf_slock);
        mutex_init(&cfg->ctx_tbl_list_mutex);
        mutex_init(&cfg->ctx_recovery_mutex);
        init_rwsem(&cfg->ioctl_rwsem);
        INIT_LIST_HEAD(&cfg->ctx_err_recovery);
        INIT_LIST_HEAD(&cfg->lluns);

        pci_set_drvdata(pdev, cfg);

        cfg->cxl_afu = cxl_pci_to_afu(pdev);

        rc = init_pci(cfg);
        if (rc) {
                dev_err(dev, "%s: init_pci failed rc=%d\n", __func__, rc);
                goto out_remove;
        }
        cfg->init_state = INIT_STATE_PCI;

        rc = init_afu(cfg);
        if (rc && !wq_has_sleeper(&cfg->reset_waitq)) {
                dev_err(dev, "%s: init_afu failed rc=%d\n", __func__, rc);
                goto out_remove;
        }
        cfg->init_state = INIT_STATE_AFU;

        rc = init_scsi(cfg);
        if (rc) {
                dev_err(dev, "%s: init_scsi failed rc=%d\n", __func__, rc);
                goto out_remove;
        }
        cfg->init_state = INIT_STATE_SCSI;

        rc = init_chrdev(cfg);
        if (rc) {
                dev_err(dev, "%s: init_chrdev failed rc=%d\n", __func__, rc);
                goto out_remove;
        }
        cfg->init_state = INIT_STATE_CDEV;

        if (wq_has_sleeper(&cfg->reset_waitq)) {
                cfg->state = STATE_PROBED;
                wake_up_all(&cfg->reset_waitq);
        } else
                cfg->state = STATE_NORMAL;
out:
        dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
        return rc;

out_remove:
        cfg->state = STATE_PROBED;
        cxlflash_remove(pdev);
        goto out;
}

/**
 * cxlflash_pci_error_detected() - called when a PCI error is detected
 * @pdev:       PCI device struct.
 * @state:      PCI channel state.
 *
 * When an EEH occurs during an active reset, wait until the reset is
 * complete and then take action based upon the device state.
 *
 * Return: PCI_ERS_RESULT_NEED_RESET or PCI_ERS_RESULT_DISCONNECT
 */
static pci_ers_result_t cxlflash_pci_error_detected(struct pci_dev *pdev,
                                                    pci_channel_state_t state)
{
        int rc = 0;
        struct cxlflash_cfg *cfg = pci_get_drvdata(pdev);
        struct device *dev = &cfg->dev->dev;

        dev_dbg(dev, "%s: pdev=%p state=%u\n", __func__, pdev, state);

        switch (state) {
        case pci_channel_io_frozen:
                wait_event(cfg->reset_waitq, cfg->state != STATE_RESET &&
                                             cfg->state != STATE_PROBING);
                if (cfg->state == STATE_FAILTERM)
                        return PCI_ERS_RESULT_DISCONNECT;

                cfg->state = STATE_RESET;
                scsi_block_requests(cfg->host);
                drain_ioctls(cfg);
                rc = cxlflash_mark_contexts_error(cfg);
                if (unlikely(rc))
                        dev_err(dev, "%s: Failed to mark user contexts rc=%d\n",
                                __func__, rc);
                term_afu(cfg);
                return PCI_ERS_RESULT_NEED_RESET;
        case pci_channel_io_perm_failure:
                cfg->state = STATE_FAILTERM;
                wake_up_all(&cfg->reset_waitq);
                scsi_unblock_requests(cfg->host);
                return PCI_ERS_RESULT_DISCONNECT;
        default:
                break;
        }
        return PCI_ERS_RESULT_NEED_RESET;
}

/**
 * cxlflash_pci_slot_reset() - called when PCI slot has been reset
 * @pdev:       PCI device struct.
 *
 * This routine is called by the pci error recovery code after the PCI
 * slot has been reset, just before we should resume normal operations.
 *
 * Return: PCI_ERS_RESULT_RECOVERED or PCI_ERS_RESULT_DISCONNECT
 */
static pci_ers_result_t cxlflash_pci_slot_reset(struct pci_dev *pdev)
{
        int rc = 0;
        struct cxlflash_cfg *cfg = pci_get_drvdata(pdev);
        struct device *dev = &cfg->dev->dev;

        dev_dbg(dev, "%s: pdev=%p\n", __func__, pdev);

        rc = init_afu(cfg);
        if (unlikely(rc)) {
                dev_err(dev, "%s: EEH recovery failed rc=%d\n", __func__, rc);
                return PCI_ERS_RESULT_DISCONNECT;
        }

        return PCI_ERS_RESULT_RECOVERED;
}

/**
 * cxlflash_pci_resume() - called when normal operation can resume
 * @pdev:       PCI device struct
 */
static void cxlflash_pci_resume(struct pci_dev *pdev)
{
        struct cxlflash_cfg *cfg = pci_get_drvdata(pdev);
        struct device *dev = &cfg->dev->dev;

        dev_dbg(dev, "%s: pdev=%p\n", __func__, pdev);

        cfg->state = STATE_NORMAL;
        wake_up_all(&cfg->reset_waitq);
        scsi_unblock_requests(cfg->host);
}

/**
 * cxlflash_devnode() - provides devtmpfs for devices in the cxlflash class
 * @dev:        Character device.
 * @mode:       Mode that can be used to verify access.
 *
 * Return: Allocated string describing the devtmpfs structure.
 */
static char *cxlflash_devnode(struct device *dev, umode_t *mode)
{
        return kasprintf(GFP_KERNEL, "cxlflash/%s", dev_name(dev));
}

/**
 * cxlflash_class_init() - create character device class
 *
 * Return: 0 on success, -errno on failure
 */
static int cxlflash_class_init(void)
{
        dev_t devno;
        int rc = 0;

        rc = alloc_chrdev_region(&devno, 0, CXLFLASH_MAX_ADAPTERS, "cxlflash");
        if (unlikely(rc)) {
                pr_err("%s: alloc_chrdev_region failed rc=%d\n", __func__, rc);
                goto out;
        }

        cxlflash_major = MAJOR(devno);

        cxlflash_class = class_create(THIS_MODULE, "cxlflash");
        if (IS_ERR(cxlflash_class)) {
                rc = PTR_ERR(cxlflash_class);
                pr_err("%s: class_create failed rc=%d\n", __func__, rc);
                goto err;
        }

        cxlflash_class->devnode = cxlflash_devnode;
out:
        pr_debug("%s: returning rc=%d\n", __func__, rc);
        return rc;
err:
        unregister_chrdev_region(devno, CXLFLASH_MAX_ADAPTERS);
        goto out;
}

/**
 * cxlflash_class_exit() - destroy character device class
 */
static void cxlflash_class_exit(void)
{
        dev_t devno = MKDEV(cxlflash_major, 0);

        class_destroy(cxlflash_class);
        unregister_chrdev_region(devno, CXLFLASH_MAX_ADAPTERS);
}

static const struct pci_error_handlers cxlflash_err_handler = {
        .error_detected = cxlflash_pci_error_detected,
        .slot_reset = cxlflash_pci_slot_reset,
        .resume = cxlflash_pci_resume,
};

/*
 * PCI device structure
 */
static struct pci_driver cxlflash_driver = {
        .name = CXLFLASH_NAME,
        .id_table = cxlflash_pci_table,
        .probe = cxlflash_probe,
        .remove = cxlflash_remove,
        .shutdown = cxlflash_remove,
        .err_handler = &cxlflash_err_handler,
};

/**
 * init_cxlflash() - module entry point
 *
 * Return: 0 on success, -errno on failure
 */
static int __init init_cxlflash(void)
{
        int rc;

        check_sizes();
        cxlflash_list_init();
        rc = cxlflash_class_init();
        if (unlikely(rc))
                goto out;

        rc = pci_register_driver(&cxlflash_driver);
        if (unlikely(rc))
                goto err;
out:
        pr_debug("%s: returning rc=%d\n", __func__, rc);
        return rc;
err:
        cxlflash_class_exit();
        goto out;
}

/**
 * exit_cxlflash() - module exit point
 */
static void __exit exit_cxlflash(void)
{
        cxlflash_term_global_luns();
        cxlflash_free_errpage();

        pci_unregister_driver(&cxlflash_driver);
        cxlflash_class_exit();
}

module_init(init_cxlflash);
module_exit(exit_cxlflash);