GNU Linux-libre 5.10.215-gnu1

[releases.git] / drivers / remoteproc / remoteproc_core.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Remote Processor Framework
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Copyright (C) 2011 Google, Inc.
 *
 * Ohad Ben-Cohen <ohad@wizery.com>
 * Brian Swetland <swetland@google.com>
 * Mark Grosen <mgrosen@ti.com>
 * Fernando Guzman Lugo <fernando.lugo@ti.com>
 * Suman Anna <s-anna@ti.com>
 * Robert Tivy <rtivy@ti.com>
 * Armando Uribe De Leon <x0095078@ti.com>
 */

#define pr_fmt(fmt)    "%s: " fmt, __func__

#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/dma-map-ops.h>
#include <linux/dma-mapping.h>
#include <linux/dma-direct.h> /* XXX: pokes into bus_dma_range */
#include <linux/firmware.h>
#include <linux/string.h>
#include <linux/debugfs.h>
#include <linux/rculist.h>
#include <linux/remoteproc.h>
#include <linux/iommu.h>
#include <linux/idr.h>
#include <linux/elf.h>
#include <linux/crc32.h>
#include <linux/of_reserved_mem.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_ring.h>
#include <asm/byteorder.h>
#include <linux/platform_device.h>

#include "remoteproc_internal.h"

#define HIGH_BITS_MASK 0xFFFFFFFF00000000ULL

static DEFINE_MUTEX(rproc_list_mutex);
static LIST_HEAD(rproc_list);
static struct notifier_block rproc_panic_nb;

typedef int (*rproc_handle_resource_t)(struct rproc *rproc,
                                 void *, int offset, int avail);

static int rproc_alloc_carveout(struct rproc *rproc,
                                struct rproc_mem_entry *mem);
static int rproc_release_carveout(struct rproc *rproc,
                                  struct rproc_mem_entry *mem);

/* Unique indices for remoteproc devices */
static DEFINE_IDA(rproc_dev_index);

static const char * const rproc_crash_names[] = {
        [RPROC_MMUFAULT]        = "mmufault",
        [RPROC_WATCHDOG]        = "watchdog",
        [RPROC_FATAL_ERROR]     = "fatal error",
};

/* translate rproc_crash_type to string */
static const char *rproc_crash_to_string(enum rproc_crash_type type)
{
        if (type < ARRAY_SIZE(rproc_crash_names))
                return rproc_crash_names[type];
        return "unknown";
}

/*
 * This is the IOMMU fault handler we register with the IOMMU API
 * (when relevant; not all remote processors access memory through
 * an IOMMU).
 *
 * IOMMU core will invoke this handler whenever the remote processor
 * will try to access an unmapped device address.
 */
static int rproc_iommu_fault(struct iommu_domain *domain, struct device *dev,
                             unsigned long iova, int flags, void *token)
{
        struct rproc *rproc = token;

        dev_err(dev, "iommu fault: da 0x%lx flags 0x%x\n", iova, flags);

        rproc_report_crash(rproc, RPROC_MMUFAULT);

        /*
         * Let the iommu core know we're not really handling this fault;
         * we just used it as a recovery trigger.
         */
        return -ENOSYS;
}

static int rproc_enable_iommu(struct rproc *rproc)
{
        struct iommu_domain *domain;
        struct device *dev = rproc->dev.parent;
        int ret;

        if (!rproc->has_iommu) {
                dev_dbg(dev, "iommu not present\n");
                return 0;
        }

        domain = iommu_domain_alloc(dev->bus);
        if (!domain) {
                dev_err(dev, "can't alloc iommu domain\n");
                return -ENOMEM;
        }

        iommu_set_fault_handler(domain, rproc_iommu_fault, rproc);

        ret = iommu_attach_device(domain, dev);
        if (ret) {
                dev_err(dev, "can't attach iommu device: %d\n", ret);
                goto free_domain;
        }

        rproc->domain = domain;

        return 0;

free_domain:
        iommu_domain_free(domain);
        return ret;
}

static void rproc_disable_iommu(struct rproc *rproc)
{
        struct iommu_domain *domain = rproc->domain;
        struct device *dev = rproc->dev.parent;

        if (!domain)
                return;

        iommu_detach_device(domain, dev);
        iommu_domain_free(domain);
}

phys_addr_t rproc_va_to_pa(void *cpu_addr)
{
        /*
         * Return physical address according to virtual address location
         * - in vmalloc: if region ioremapped or defined as dma_alloc_coherent
         * - in kernel: if region allocated in generic dma memory pool
         */
        if (is_vmalloc_addr(cpu_addr)) {
                return page_to_phys(vmalloc_to_page(cpu_addr)) +
                                    offset_in_page(cpu_addr);
        }

        WARN_ON(!virt_addr_valid(cpu_addr));
        return virt_to_phys(cpu_addr);
}
EXPORT_SYMBOL(rproc_va_to_pa);

/**
 * rproc_da_to_va() - lookup the kernel virtual address for a remoteproc address
 * @rproc: handle of a remote processor
 * @da: remoteproc device address to translate
 * @len: length of the memory region @da is pointing to
 *
 * Some remote processors will ask us to allocate them physically contiguous
 * memory regions (which we call "carveouts"), and map them to specific
 * device addresses (which are hardcoded in the firmware). They may also have
 * dedicated memory regions internal to the processors, and use them either
 * exclusively or alongside carveouts.
 *
 * They may then ask us to copy objects into specific device addresses (e.g.
 * code/data sections) or expose us certain symbols in other device address
 * (e.g. their trace buffer).
 *
 * This function is a helper function with which we can go over the allocated
 * carveouts and translate specific device addresses to kernel virtual addresses
 * so we can access the referenced memory. This function also allows to perform
 * translations on the internal remoteproc memory regions through a platform
 * implementation specific da_to_va ops, if present.
 *
 * The function returns a valid kernel address on success or NULL on failure.
 *
 * Note: phys_to_virt(iommu_iova_to_phys(rproc->domain, da)) will work too,
 * but only on kernel direct mapped RAM memory. Instead, we're just using
 * here the output of the DMA API for the carveouts, which should be more
 * correct.
 */
void *rproc_da_to_va(struct rproc *rproc, u64 da, size_t len)
{
        struct rproc_mem_entry *carveout;
        void *ptr = NULL;

        if (rproc->ops->da_to_va) {
                ptr = rproc->ops->da_to_va(rproc, da, len);
                if (ptr)
                        goto out;
        }

        list_for_each_entry(carveout, &rproc->carveouts, node) {
                int offset = da - carveout->da;

                /*  Verify that carveout is allocated */
                if (!carveout->va)
                        continue;

                /* try next carveout if da is too small */
                if (offset < 0)
                        continue;

                /* try next carveout if da is too large */
                if (offset + len > carveout->len)
                        continue;

                ptr = carveout->va + offset;

                break;
        }

out:
        return ptr;
}
EXPORT_SYMBOL(rproc_da_to_va);

/**
 * rproc_find_carveout_by_name() - lookup the carveout region by a name
 * @rproc: handle of a remote processor
 * @name: carveout name to find (format string)
 * @...: optional parameters matching @name string
 *
 * Platform driver has the capability to register some pre-allacoted carveout
 * (physically contiguous memory regions) before rproc firmware loading and
 * associated resource table analysis. These regions may be dedicated memory
 * regions internal to the coprocessor or specified DDR region with specific
 * attributes
 *
 * This function is a helper function with which we can go over the
 * allocated carveouts and return associated region characteristics like
 * coprocessor address, length or processor virtual address.
 *
 * Return: a valid pointer on carveout entry on success or NULL on failure.
 */
__printf(2, 3)
struct rproc_mem_entry *
rproc_find_carveout_by_name(struct rproc *rproc, const char *name, ...)
{
        va_list args;
        char _name[32];
        struct rproc_mem_entry *carveout, *mem = NULL;

        if (!name)
                return NULL;

        va_start(args, name);
        vsnprintf(_name, sizeof(_name), name, args);
        va_end(args);

        list_for_each_entry(carveout, &rproc->carveouts, node) {
                /* Compare carveout and requested names */
                if (!strcmp(carveout->name, _name)) {
                        mem = carveout;
                        break;
                }
        }

        return mem;
}

/**
 * rproc_check_carveout_da() - Check specified carveout da configuration
 * @rproc: handle of a remote processor
 * @mem: pointer on carveout to check
 * @da: area device address
 * @len: associated area size
 *
 * This function is a helper function to verify requested device area (couple
 * da, len) is part of specified carveout.
 * If da is not set (defined as FW_RSC_ADDR_ANY), only requested length is
 * checked.
 *
 * Return: 0 if carveout matches request else error
 */
static int rproc_check_carveout_da(struct rproc *rproc,
                                   struct rproc_mem_entry *mem, u32 da, u32 len)
{
        struct device *dev = &rproc->dev;
        int delta;

        /* Check requested resource length */
        if (len > mem->len) {
                dev_err(dev, "Registered carveout doesn't fit len request\n");
                return -EINVAL;
        }

        if (da != FW_RSC_ADDR_ANY && mem->da == FW_RSC_ADDR_ANY) {
                /* Address doesn't match registered carveout configuration */
                return -EINVAL;
        } else if (da != FW_RSC_ADDR_ANY && mem->da != FW_RSC_ADDR_ANY) {
                delta = da - mem->da;

                /* Check requested resource belongs to registered carveout */
                if (delta < 0) {
                        dev_err(dev,
                                "Registered carveout doesn't fit da request\n");
                        return -EINVAL;
                }

                if (delta + len > mem->len) {
                        dev_err(dev,
                                "Registered carveout doesn't fit len request\n");
                        return -EINVAL;
                }
        }

        return 0;
}

int rproc_alloc_vring(struct rproc_vdev *rvdev, int i)
{
        struct rproc *rproc = rvdev->rproc;
        struct device *dev = &rproc->dev;
        struct rproc_vring *rvring = &rvdev->vring[i];
        struct fw_rsc_vdev *rsc;
        int ret, notifyid;
        struct rproc_mem_entry *mem;
        size_t size;

        /* actual size of vring (in bytes) */
        size = PAGE_ALIGN(vring_size(rvring->len, rvring->align));

        rsc = (void *)rproc->table_ptr + rvdev->rsc_offset;

        /* Search for pre-registered carveout */
        mem = rproc_find_carveout_by_name(rproc, "vdev%dvring%d", rvdev->index,
                                          i);
        if (mem) {
                if (rproc_check_carveout_da(rproc, mem, rsc->vring[i].da, size))
                        return -ENOMEM;
        } else {
                /* Register carveout in in list */
                mem = rproc_mem_entry_init(dev, NULL, 0,
                                           size, rsc->vring[i].da,
                                           rproc_alloc_carveout,
                                           rproc_release_carveout,
                                           "vdev%dvring%d",
                                           rvdev->index, i);
                if (!mem) {
                        dev_err(dev, "Can't allocate memory entry structure\n");
                        return -ENOMEM;
                }

                rproc_add_carveout(rproc, mem);
        }

        /*
         * Assign an rproc-wide unique index for this vring
         * TODO: assign a notifyid for rvdev updates as well
         * TODO: support predefined notifyids (via resource table)
         */
        ret = idr_alloc(&rproc->notifyids, rvring, 0, 0, GFP_KERNEL);
        if (ret < 0) {
                dev_err(dev, "idr_alloc failed: %d\n", ret);
                return ret;
        }
        notifyid = ret;

        /* Potentially bump max_notifyid */
        if (notifyid > rproc->max_notifyid)
                rproc->max_notifyid = notifyid;

        rvring->notifyid = notifyid;

        /* Let the rproc know the notifyid of this vring.*/
        rsc->vring[i].notifyid = notifyid;
        return 0;
}

static int
rproc_parse_vring(struct rproc_vdev *rvdev, struct fw_rsc_vdev *rsc, int i)
{
        struct rproc *rproc = rvdev->rproc;
        struct device *dev = &rproc->dev;
        struct fw_rsc_vdev_vring *vring = &rsc->vring[i];
        struct rproc_vring *rvring = &rvdev->vring[i];

        dev_dbg(dev, "vdev rsc: vring%d: da 0x%x, qsz %d, align %d\n",
                i, vring->da, vring->num, vring->align);

        /* verify queue size and vring alignment are sane */
        if (!vring->num || !vring->align) {
                dev_err(dev, "invalid qsz (%d) or alignment (%d)\n",
                        vring->num, vring->align);
                return -EINVAL;
        }

        rvring->len = vring->num;
        rvring->align = vring->align;
        rvring->rvdev = rvdev;

        return 0;
}

void rproc_free_vring(struct rproc_vring *rvring)
{
        struct rproc *rproc = rvring->rvdev->rproc;
        int idx = rvring - rvring->rvdev->vring;
        struct fw_rsc_vdev *rsc;

        idr_remove(&rproc->notifyids, rvring->notifyid);

        /*
         * At this point rproc_stop() has been called and the installed resource
         * table in the remote processor memory may no longer be accessible. As
         * such and as per rproc_stop(), rproc->table_ptr points to the cached
         * resource table (rproc->cached_table).  The cached resource table is
         * only available when a remote processor has been booted by the
         * remoteproc core, otherwise it is NULL.
         *
         * Based on the above, reset the virtio device section in the cached
         * resource table only if there is one to work with.
         */
        if (rproc->table_ptr) {
                rsc = (void *)rproc->table_ptr + rvring->rvdev->rsc_offset;
                rsc->vring[idx].da = 0;
                rsc->vring[idx].notifyid = -1;
        }
}

static int rproc_vdev_do_start(struct rproc_subdev *subdev)
{
        struct rproc_vdev *rvdev = container_of(subdev, struct rproc_vdev, subdev);

        return rproc_add_virtio_dev(rvdev, rvdev->id);
}

static void rproc_vdev_do_stop(struct rproc_subdev *subdev, bool crashed)
{
        struct rproc_vdev *rvdev = container_of(subdev, struct rproc_vdev, subdev);
        int ret;

        ret = device_for_each_child(&rvdev->dev, NULL, rproc_remove_virtio_dev);
        if (ret)
                dev_warn(&rvdev->dev, "can't remove vdev child device: %d\n", ret);
}

/**
 * rproc_rvdev_release() - release the existence of a rvdev
 *
 * @dev: the subdevice's dev
 */
static void rproc_rvdev_release(struct device *dev)
{
        struct rproc_vdev *rvdev = container_of(dev, struct rproc_vdev, dev);

        of_reserved_mem_device_release(dev);

        kfree(rvdev);
}

static int copy_dma_range_map(struct device *to, struct device *from)
{
        const struct bus_dma_region *map = from->dma_range_map, *new_map, *r;
        int num_ranges = 0;

        if (!map)
                return 0;

        for (r = map; r->size; r++)
                num_ranges++;

        new_map = kmemdup(map, array_size(num_ranges + 1, sizeof(*map)),
                          GFP_KERNEL);
        if (!new_map)
                return -ENOMEM;
        to->dma_range_map = new_map;
        return 0;
}

/**
 * rproc_handle_vdev() - handle a vdev fw resource
 * @rproc: the remote processor
 * @rsc: the vring resource descriptor
 * @offset: offset of the resource entry
 * @avail: size of available data (for sanity checking the image)
 *
 * This resource entry requests the host to statically register a virtio
 * device (vdev), and setup everything needed to support it. It contains
 * everything needed to make it possible: the virtio device id, virtio
 * device features, vrings information, virtio config space, etc...
 *
 * Before registering the vdev, the vrings are allocated from non-cacheable
 * physically contiguous memory. Currently we only support two vrings per
 * remote processor (temporary limitation). We might also want to consider
 * doing the vring allocation only later when ->find_vqs() is invoked, and
 * then release them upon ->del_vqs().
 *
 * Note: @da is currently not really handled correctly: we dynamically
 * allocate it using the DMA API, ignoring requested hard coded addresses,
 * and we don't take care of any required IOMMU programming. This is all
 * going to be taken care of when the generic iommu-based DMA API will be
 * merged. Meanwhile, statically-addressed iommu-based firmware images should
 * use RSC_DEVMEM resource entries to map their required @da to the physical
 * address of their base CMA region (ouch, hacky!).
 *
 * Returns 0 on success, or an appropriate error code otherwise
 */
static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
                             int offset, int avail)
{
        struct device *dev = &rproc->dev;
        struct rproc_vdev *rvdev;
        int i, ret;
        char name[16];

        /* make sure resource isn't truncated */
        if (struct_size(rsc, vring, rsc->num_of_vrings) + rsc->config_len >
                        avail) {
                dev_err(dev, "vdev rsc is truncated\n");
                return -EINVAL;
        }

        /* make sure reserved bytes are zeroes */
        if (rsc->reserved[0] || rsc->reserved[1]) {
                dev_err(dev, "vdev rsc has non zero reserved bytes\n");
                return -EINVAL;
        }

        dev_dbg(dev, "vdev rsc: id %d, dfeatures 0x%x, cfg len %d, %d vrings\n",
                rsc->id, rsc->dfeatures, rsc->config_len, rsc->num_of_vrings);

        /* we currently support only two vrings per rvdev */
        if (rsc->num_of_vrings > ARRAY_SIZE(rvdev->vring)) {
                dev_err(dev, "too many vrings: %d\n", rsc->num_of_vrings);
                return -EINVAL;
        }

        rvdev = kzalloc(sizeof(*rvdev), GFP_KERNEL);
        if (!rvdev)
                return -ENOMEM;

        kref_init(&rvdev->refcount);

        rvdev->id = rsc->id;
        rvdev->rproc = rproc;
        rvdev->index = rproc->nb_vdev++;

        /* Initialise vdev subdevice */
        snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
        rvdev->dev.parent = &rproc->dev;
        rvdev->dev.release = rproc_rvdev_release;
        dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);
        dev_set_drvdata(&rvdev->dev, rvdev);

        ret = device_register(&rvdev->dev);
        if (ret) {
                put_device(&rvdev->dev);
                return ret;
        }

        ret = copy_dma_range_map(&rvdev->dev, rproc->dev.parent);
        if (ret)
                goto free_rvdev;

        /* Make device dma capable by inheriting from parent's capabilities */
        set_dma_ops(&rvdev->dev, get_dma_ops(rproc->dev.parent));

        ret = dma_coerce_mask_and_coherent(&rvdev->dev,
                                           dma_get_mask(rproc->dev.parent));
        if (ret) {
                dev_warn(dev,
                         "Failed to set DMA mask %llx. Trying to continue... %x\n",
                         dma_get_mask(rproc->dev.parent), ret);
        }

        /* parse the vrings */
        for (i = 0; i < rsc->num_of_vrings; i++) {
                ret = rproc_parse_vring(rvdev, rsc, i);
                if (ret)
                        goto free_rvdev;
        }

        /* remember the resource offset*/
        rvdev->rsc_offset = offset;

        /* allocate the vring resources */
        for (i = 0; i < rsc->num_of_vrings; i++) {
                ret = rproc_alloc_vring(rvdev, i);
                if (ret)
                        goto unwind_vring_allocations;
        }

        list_add_tail(&rvdev->node, &rproc->rvdevs);

        rvdev->subdev.start = rproc_vdev_do_start;
        rvdev->subdev.stop = rproc_vdev_do_stop;

        rproc_add_subdev(rproc, &rvdev->subdev);

        return 0;

unwind_vring_allocations:
        for (i--; i >= 0; i--)
                rproc_free_vring(&rvdev->vring[i]);
free_rvdev:
        device_unregister(&rvdev->dev);
        return ret;
}

void rproc_vdev_release(struct kref *ref)
{
        struct rproc_vdev *rvdev = container_of(ref, struct rproc_vdev, refcount);
        struct rproc_vring *rvring;
        struct rproc *rproc = rvdev->rproc;
        int id;

        for (id = 0; id < ARRAY_SIZE(rvdev->vring); id++) {
                rvring = &rvdev->vring[id];
                rproc_free_vring(rvring);
        }

        rproc_remove_subdev(rproc, &rvdev->subdev);
        list_del(&rvdev->node);
        device_unregister(&rvdev->dev);
}

/**
 * rproc_handle_trace() - handle a shared trace buffer resource
 * @rproc: the remote processor
 * @rsc: the trace resource descriptor
 * @offset: offset of the resource entry
 * @avail: size of available data (for sanity checking the image)
 *
 * In case the remote processor dumps trace logs into memory,
 * export it via debugfs.
 *
 * Currently, the 'da' member of @rsc should contain the device address
 * where the remote processor is dumping the traces. Later we could also
 * support dynamically allocating this address using the generic
 * DMA API (but currently there isn't a use case for that).
 *
 * Returns 0 on success, or an appropriate error code otherwise
 */
static int rproc_handle_trace(struct rproc *rproc, struct fw_rsc_trace *rsc,
                              int offset, int avail)
{
        struct rproc_debug_trace *trace;
        struct device *dev = &rproc->dev;
        char name[15];

        if (sizeof(*rsc) > avail) {
                dev_err(dev, "trace rsc is truncated\n");
                return -EINVAL;
        }

        /* make sure reserved bytes are zeroes */
        if (rsc->reserved) {
                dev_err(dev, "trace rsc has non zero reserved bytes\n");
                return -EINVAL;
        }

        trace = kzalloc(sizeof(*trace), GFP_KERNEL);
        if (!trace)
                return -ENOMEM;

        /* set the trace buffer dma properties */
        trace->trace_mem.len = rsc->len;
        trace->trace_mem.da = rsc->da;

        /* set pointer on rproc device */
        trace->rproc = rproc;

        /* make sure snprintf always null terminates, even if truncating */
        snprintf(name, sizeof(name), "trace%d", rproc->num_traces);

        /* create the debugfs entry */
        trace->tfile = rproc_create_trace_file(name, rproc, trace);
        if (!trace->tfile) {
                kfree(trace);
                return -EINVAL;
        }

        list_add_tail(&trace->node, &rproc->traces);

        rproc->num_traces++;

        dev_dbg(dev, "%s added: da 0x%x, len 0x%x\n",
                name, rsc->da, rsc->len);

        return 0;
}

/**
 * rproc_handle_devmem() - handle devmem resource entry
 * @rproc: remote processor handle
 * @rsc: the devmem resource entry
 * @offset: offset of the resource entry
 * @avail: size of available data (for sanity checking the image)
 *
 * Remote processors commonly need to access certain on-chip peripherals.
 *
 * Some of these remote processors access memory via an iommu device,
 * and might require us to configure their iommu before they can access
 * the on-chip peripherals they need.
 *
 * This resource entry is a request to map such a peripheral device.
 *
 * These devmem entries will contain the physical address of the device in
 * the 'pa' member. If a specific device address is expected, then 'da' will
 * contain it (currently this is the only use case supported). 'len' will
 * contain the size of the physical region we need to map.
 *
 * Currently we just "trust" those devmem entries to contain valid physical
 * addresses, but this is going to change: we want the implementations to
 * tell us ranges of physical addresses the firmware is allowed to request,
 * and not allow firmwares to request access to physical addresses that
 * are outside those ranges.
 */
static int rproc_handle_devmem(struct rproc *rproc, struct fw_rsc_devmem *rsc,
                               int offset, int avail)
{
        struct rproc_mem_entry *mapping;
        struct device *dev = &rproc->dev;
        int ret;

        /* no point in handling this resource without a valid iommu domain */
        if (!rproc->domain)
                return -EINVAL;

        if (sizeof(*rsc) > avail) {
                dev_err(dev, "devmem rsc is truncated\n");
                return -EINVAL;
        }

        /* make sure reserved bytes are zeroes */
        if (rsc->reserved) {
                dev_err(dev, "devmem rsc has non zero reserved bytes\n");
                return -EINVAL;
        }

        mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
        if (!mapping)
                return -ENOMEM;

        ret = iommu_map(rproc->domain, rsc->da, rsc->pa, rsc->len, rsc->flags);
        if (ret) {
                dev_err(dev, "failed to map devmem: %d\n", ret);
                goto out;
        }

        /*
         * We'll need this info later when we'll want to unmap everything
         * (e.g. on shutdown).
         *
         * We can't trust the remote processor not to change the resource
         * table, so we must maintain this info independently.
         */
        mapping->da = rsc->da;
        mapping->len = rsc->len;
        list_add_tail(&mapping->node, &rproc->mappings);

        dev_dbg(dev, "mapped devmem pa 0x%x, da 0x%x, len 0x%x\n",
                rsc->pa, rsc->da, rsc->len);

        return 0;

out:
        kfree(mapping);
        return ret;
}

/**
 * rproc_alloc_carveout() - allocated specified carveout
 * @rproc: rproc handle
 * @mem: the memory entry to allocate
 *
 * This function allocate specified memory entry @mem using
 * dma_alloc_coherent() as default allocator
 */
static int rproc_alloc_carveout(struct rproc *rproc,
                                struct rproc_mem_entry *mem)
{
        struct rproc_mem_entry *mapping = NULL;
        struct device *dev = &rproc->dev;
        dma_addr_t dma;
        void *va;
        int ret;

        va = dma_alloc_coherent(dev->parent, mem->len, &dma, GFP_KERNEL);
        if (!va) {
                dev_err(dev->parent,
                        "failed to allocate dma memory: len 0x%zx\n",
                        mem->len);
                return -ENOMEM;
        }

        dev_dbg(dev, "carveout va %pK, dma %pad, len 0x%zx\n",
                va, &dma, mem->len);

        if (mem->da != FW_RSC_ADDR_ANY && !rproc->domain) {
                /*
                 * Check requested da is equal to dma address
                 * and print a warn message in case of missalignment.
                 * Don't stop rproc_start sequence as coprocessor may
                 * build pa to da translation on its side.
                 */
                if (mem->da != (u32)dma)
                        dev_warn(dev->parent,
                                 "Allocated carveout doesn't fit device address request\n");
        }

        /*
         * Ok, this is non-standard.
         *
         * Sometimes we can't rely on the generic iommu-based DMA API
         * to dynamically allocate the device address and then set the IOMMU
         * tables accordingly, because some remote processors might
         * _require_ us to use hard coded device addresses that their
         * firmware was compiled with.
         *
         * In this case, we must use the IOMMU API directly and map
         * the memory to the device address as expected by the remote
         * processor.
         *
         * Obviously such remote processor devices should not be configured
         * to use the iommu-based DMA API: we expect 'dma' to contain the
         * physical address in this case.
         */
        if (mem->da != FW_RSC_ADDR_ANY && rproc->domain) {
                mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
                if (!mapping) {
                        ret = -ENOMEM;
                        goto dma_free;
                }

                ret = iommu_map(rproc->domain, mem->da, dma, mem->len,
                                mem->flags);
                if (ret) {
                        dev_err(dev, "iommu_map failed: %d\n", ret);
                        goto free_mapping;
                }

                /*
                 * We'll need this info later when we'll want to unmap
                 * everything (e.g. on shutdown).
                 *
                 * We can't trust the remote processor not to change the
                 * resource table, so we must maintain this info independently.
                 */
                mapping->da = mem->da;
                mapping->len = mem->len;
                list_add_tail(&mapping->node, &rproc->mappings);

                dev_dbg(dev, "carveout mapped 0x%x to %pad\n",
                        mem->da, &dma);
        }

        if (mem->da == FW_RSC_ADDR_ANY) {
                /* Update device address as undefined by requester */
                if ((u64)dma & HIGH_BITS_MASK)
                        dev_warn(dev, "DMA address cast in 32bit to fit resource table format\n");

                mem->da = (u32)dma;
        }

        mem->dma = dma;
        mem->va = va;

        return 0;

free_mapping:
        kfree(mapping);
dma_free:
        dma_free_coherent(dev->parent, mem->len, va, dma);
        return ret;
}

/**
 * rproc_release_carveout() - release acquired carveout
 * @rproc: rproc handle
 * @mem: the memory entry to release
 *
 * This function releases specified memory entry @mem allocated via
 * rproc_alloc_carveout() function by @rproc.
 */
static int rproc_release_carveout(struct rproc *rproc,
                                  struct rproc_mem_entry *mem)
{
        struct device *dev = &rproc->dev;

        /* clean up carveout allocations */
        dma_free_coherent(dev->parent, mem->len, mem->va, mem->dma);
        return 0;
}

/**
 * rproc_handle_carveout() - handle phys contig memory allocation requests
 * @rproc: rproc handle
 * @rsc: the resource entry
 * @offset: offset of the resource entry
 * @avail: size of available data (for image validation)
 *
 * This function will handle firmware requests for allocation of physically
 * contiguous memory regions.
 *
 * These request entries should come first in the firmware's resource table,
 * as other firmware entries might request placing other data objects inside
 * these memory regions (e.g. data/code segments, trace resource entries, ...).
 *
 * Allocating memory this way helps utilizing the reserved physical memory
 * (e.g. CMA) more efficiently, and also minimizes the number of TLB entries
 * needed to map it (in case @rproc is using an IOMMU). Reducing the TLB
 * pressure is important; it may have a substantial impact on performance.
 */
static int rproc_handle_carveout(struct rproc *rproc,
                                 struct fw_rsc_carveout *rsc,
                                 int offset, int avail)
{
        struct rproc_mem_entry *carveout;
        struct device *dev = &rproc->dev;

        if (sizeof(*rsc) > avail) {
                dev_err(dev, "carveout rsc is truncated\n");
                return -EINVAL;
        }

        /* make sure reserved bytes are zeroes */
        if (rsc->reserved) {
                dev_err(dev, "carveout rsc has non zero reserved bytes\n");
                return -EINVAL;
        }

        dev_dbg(dev, "carveout rsc: name: %s, da 0x%x, pa 0x%x, len 0x%x, flags 0x%x\n",
                rsc->name, rsc->da, rsc->pa, rsc->len, rsc->flags);

        /*
         * Check carveout rsc already part of a registered carveout,
         * Search by name, then check the da and length
         */
        carveout = rproc_find_carveout_by_name(rproc, rsc->name);

        if (carveout) {
                if (carveout->rsc_offset != FW_RSC_ADDR_ANY) {
                        dev_err(dev,
                                "Carveout already associated to resource table\n");
                        return -ENOMEM;
                }

                if (rproc_check_carveout_da(rproc, carveout, rsc->da, rsc->len))
                        return -ENOMEM;

                /* Update memory carveout with resource table info */
                carveout->rsc_offset = offset;
                carveout->flags = rsc->flags;

                return 0;
        }

        /* Register carveout in in list */
        carveout = rproc_mem_entry_init(dev, NULL, 0, rsc->len, rsc->da,
                                        rproc_alloc_carveout,
                                        rproc_release_carveout, rsc->name);
        if (!carveout) {
                dev_err(dev, "Can't allocate memory entry structure\n");
                return -ENOMEM;
        }

        carveout->flags = rsc->flags;
        carveout->rsc_offset = offset;
        rproc_add_carveout(rproc, carveout);

        return 0;
}

/**
 * rproc_add_carveout() - register an allocated carveout region
 * @rproc: rproc handle
 * @mem: memory entry to register
 *
 * This function registers specified memory entry in @rproc carveouts list.
 * Specified carveout should have been allocated before registering.
 */
void rproc_add_carveout(struct rproc *rproc, struct rproc_mem_entry *mem)
{
        list_add_tail(&mem->node, &rproc->carveouts);
}
EXPORT_SYMBOL(rproc_add_carveout);

/**
 * rproc_mem_entry_init() - allocate and initialize rproc_mem_entry struct
 * @dev: pointer on device struct
 * @va: virtual address
 * @dma: dma address
 * @len: memory carveout length
 * @da: device address
 * @alloc: memory carveout allocation function
 * @release: memory carveout release function
 * @name: carveout name
 *
 * This function allocates a rproc_mem_entry struct and fill it with parameters
 * provided by client.
 */
__printf(8, 9)
struct rproc_mem_entry *
rproc_mem_entry_init(struct device *dev,
                     void *va, dma_addr_t dma, size_t len, u32 da,
                     int (*alloc)(struct rproc *, struct rproc_mem_entry *),
                     int (*release)(struct rproc *, struct rproc_mem_entry *),
                     const char *name, ...)
{
        struct rproc_mem_entry *mem;
        va_list args;

        mem = kzalloc(sizeof(*mem), GFP_KERNEL);
        if (!mem)
                return mem;

        mem->va = va;
        mem->dma = dma;
        mem->da = da;
        mem->len = len;
        mem->alloc = alloc;
        mem->release = release;
        mem->rsc_offset = FW_RSC_ADDR_ANY;
        mem->of_resm_idx = -1;

        va_start(args, name);
        vsnprintf(mem->name, sizeof(mem->name), name, args);
        va_end(args);

        return mem;
}
EXPORT_SYMBOL(rproc_mem_entry_init);

/**
 * rproc_of_resm_mem_entry_init() - allocate and initialize rproc_mem_entry struct
 * from a reserved memory phandle
 * @dev: pointer on device struct
 * @of_resm_idx: reserved memory phandle index in "memory-region"
 * @len: memory carveout length
 * @da: device address
 * @name: carveout name
 *
 * This function allocates a rproc_mem_entry struct and fill it with parameters
 * provided by client.
 */
__printf(5, 6)
struct rproc_mem_entry *
rproc_of_resm_mem_entry_init(struct device *dev, u32 of_resm_idx, size_t len,
                             u32 da, const char *name, ...)
{
        struct rproc_mem_entry *mem;
        va_list args;

        mem = kzalloc(sizeof(*mem), GFP_KERNEL);
        if (!mem)
                return mem;

        mem->da = da;
        mem->len = len;
        mem->rsc_offset = FW_RSC_ADDR_ANY;
        mem->of_resm_idx = of_resm_idx;

        va_start(args, name);
        vsnprintf(mem->name, sizeof(mem->name), name, args);
        va_end(args);

        return mem;
}
EXPORT_SYMBOL(rproc_of_resm_mem_entry_init);

/**
 * rproc_of_parse_firmware() - parse and return the firmware-name
 * @dev: pointer on device struct representing a rproc
 * @index: index to use for the firmware-name retrieval
 * @fw_name: pointer to a character string, in which the firmware
 *           name is returned on success and unmodified otherwise.
 *
 * This is an OF helper function that parses a device's DT node for
 * the "firmware-name" property and returns the firmware name pointer
 * in @fw_name on success.
 *
 * Return: 0 on success, or an appropriate failure.
 */
int rproc_of_parse_firmware(struct device *dev, int index, const char **fw_name)
{
        int ret;

        ret = of_property_read_string_index(dev->of_node, "firmware-name",
                                            index, fw_name);
        return ret ? ret : 0;
}
EXPORT_SYMBOL(rproc_of_parse_firmware);

/*
 * A lookup table for resource handlers. The indices are defined in
 * enum fw_resource_type.
 */
static rproc_handle_resource_t rproc_loading_handlers[RSC_LAST] = {
        [RSC_CARVEOUT] = (rproc_handle_resource_t)rproc_handle_carveout,
        [RSC_DEVMEM] = (rproc_handle_resource_t)rproc_handle_devmem,
        [RSC_TRACE] = (rproc_handle_resource_t)rproc_handle_trace,
        [RSC_VDEV] = (rproc_handle_resource_t)rproc_handle_vdev,
};

/* handle firmware resource entries before booting the remote processor */
static int rproc_handle_resources(struct rproc *rproc,
                                  rproc_handle_resource_t handlers[RSC_LAST])
{
        struct device *dev = &rproc->dev;
        rproc_handle_resource_t handler;
        int ret = 0, i;

        if (!rproc->table_ptr)
                return 0;

        for (i = 0; i < rproc->table_ptr->num; i++) {
                int offset = rproc->table_ptr->offset[i];
                struct fw_rsc_hdr *hdr = (void *)rproc->table_ptr + offset;
                int avail = rproc->table_sz - offset - sizeof(*hdr);
                void *rsc = (void *)hdr + sizeof(*hdr);

                /* make sure table isn't truncated */
                if (avail < 0) {
                        dev_err(dev, "rsc table is truncated\n");
                        return -EINVAL;
                }

                dev_dbg(dev, "rsc: type %d\n", hdr->type);

                if (hdr->type >= RSC_VENDOR_START &&
                    hdr->type <= RSC_VENDOR_END) {
                        ret = rproc_handle_rsc(rproc, hdr->type, rsc,
                                               offset + sizeof(*hdr), avail);
                        if (ret == RSC_HANDLED)
                                continue;
                        else if (ret < 0)
                                break;

                        dev_warn(dev, "unsupported vendor resource %d\n",
                                 hdr->type);
                        continue;
                }

                if (hdr->type >= RSC_LAST) {
                        dev_warn(dev, "unsupported resource %d\n", hdr->type);
                        continue;
                }

                handler = handlers[hdr->type];
                if (!handler)
                        continue;

                ret = handler(rproc, rsc, offset + sizeof(*hdr), avail);
                if (ret)
                        break;
        }

        return ret;
}

static int rproc_prepare_subdevices(struct rproc *rproc)
{
        struct rproc_subdev *subdev;
        int ret;

        list_for_each_entry(subdev, &rproc->subdevs, node) {
                if (subdev->prepare) {
                        ret = subdev->prepare(subdev);
                        if (ret)
                                goto unroll_preparation;
                }
        }

        return 0;

unroll_preparation:
        list_for_each_entry_continue_reverse(subdev, &rproc->subdevs, node) {
                if (subdev->unprepare)
                        subdev->unprepare(subdev);
        }

        return ret;
}

static int rproc_start_subdevices(struct rproc *rproc)
{
        struct rproc_subdev *subdev;
        int ret;

        list_for_each_entry(subdev, &rproc->subdevs, node) {
                if (subdev->start) {
                        ret = subdev->start(subdev);
                        if (ret)
                                goto unroll_registration;
                }
        }

        return 0;

unroll_registration:
        list_for_each_entry_continue_reverse(subdev, &rproc->subdevs, node) {
                if (subdev->stop)
                        subdev->stop(subdev, true);
        }

        return ret;
}

static void rproc_stop_subdevices(struct rproc *rproc, bool crashed)
{
        struct rproc_subdev *subdev;

        list_for_each_entry_reverse(subdev, &rproc->subdevs, node) {
                if (subdev->stop)
                        subdev->stop(subdev, crashed);
        }
}

static void rproc_unprepare_subdevices(struct rproc *rproc)
{
        struct rproc_subdev *subdev;

        list_for_each_entry_reverse(subdev, &rproc->subdevs, node) {
                if (subdev->unprepare)
                        subdev->unprepare(subdev);
        }
}

/**
 * rproc_alloc_registered_carveouts() - allocate all carveouts registered
 * in the list
 * @rproc: the remote processor handle
 *
 * This function parses registered carveout list, performs allocation
 * if alloc() ops registered and updates resource table information
 * if rsc_offset set.
 *
 * Return: 0 on success
 */
static int rproc_alloc_registered_carveouts(struct rproc *rproc)
{
        struct rproc_mem_entry *entry, *tmp;
        struct fw_rsc_carveout *rsc;
        struct device *dev = &rproc->dev;
        u64 pa;
        int ret;

        list_for_each_entry_safe(entry, tmp, &rproc->carveouts, node) {
                if (entry->alloc) {
                        ret = entry->alloc(rproc, entry);
                        if (ret) {
                                dev_err(dev, "Unable to allocate carveout %s: %d\n",
                                        entry->name, ret);
                                return -ENOMEM;
                        }
                }

                if (entry->rsc_offset != FW_RSC_ADDR_ANY) {
                        /* update resource table */
                        rsc = (void *)rproc->table_ptr + entry->rsc_offset;

                        /*
                         * Some remote processors might need to know the pa
                         * even though they are behind an IOMMU. E.g., OMAP4's
                         * remote M3 processor needs this so it can control
                         * on-chip hardware accelerators that are not behind
                         * the IOMMU, and therefor must know the pa.
                         *
                         * Generally we don't want to expose physical addresses
                         * if we don't have to (remote processors are generally
                         * _not_ trusted), so we might want to do this only for
                         * remote processor that _must_ have this (e.g. OMAP4's
                         * dual M3 subsystem).
                         *
                         * Non-IOMMU processors might also want to have this info.
                         * In this case, the device address and the physical address
                         * are the same.
                         */

                        /* Use va if defined else dma to generate pa */
                        if (entry->va)
                                pa = (u64)rproc_va_to_pa(entry->va);
                        else
                                pa = (u64)entry->dma;

                        if (((u64)pa) & HIGH_BITS_MASK)
                                dev_warn(dev,
                                         "Physical address cast in 32bit to fit resource table format\n");

                        rsc->pa = (u32)pa;
                        rsc->da = entry->da;
                        rsc->len = entry->len;
                }
        }

        return 0;
}


/**
 * rproc_resource_cleanup() - clean up and free all acquired resources
 * @rproc: rproc handle
 *
 * This function will free all resources acquired for @rproc, and it
 * is called whenever @rproc either shuts down or fails to boot.
 */
void rproc_resource_cleanup(struct rproc *rproc)
{
        struct rproc_mem_entry *entry, *tmp;
        struct rproc_debug_trace *trace, *ttmp;
        struct rproc_vdev *rvdev, *rvtmp;
        struct device *dev = &rproc->dev;

        /* clean up debugfs trace entries */
        list_for_each_entry_safe(trace, ttmp, &rproc->traces, node) {
                rproc_remove_trace_file(trace->tfile);
                rproc->num_traces--;
                list_del(&trace->node);
                kfree(trace);
        }

        /* clean up iommu mapping entries */
        list_for_each_entry_safe(entry, tmp, &rproc->mappings, node) {
                size_t unmapped;

                unmapped = iommu_unmap(rproc->domain, entry->da, entry->len);
                if (unmapped != entry->len) {
                        /* nothing much to do besides complaining */
                        dev_err(dev, "failed to unmap %zx/%zu\n", entry->len,
                                unmapped);
                }

                list_del(&entry->node);
                kfree(entry);
        }

        /* clean up carveout allocations */
        list_for_each_entry_safe(entry, tmp, &rproc->carveouts, node) {
                if (entry->release)
                        entry->release(rproc, entry);
                list_del(&entry->node);
                kfree(entry);
        }

        /* clean up remote vdev entries */
        list_for_each_entry_safe(rvdev, rvtmp, &rproc->rvdevs, node)
                kref_put(&rvdev->refcount, rproc_vdev_release);

        rproc_coredump_cleanup(rproc);
}
EXPORT_SYMBOL(rproc_resource_cleanup);

static int rproc_start(struct rproc *rproc, const struct firmware *fw)
{
        struct resource_table *loaded_table;
        struct device *dev = &rproc->dev;
        int ret;

        /* load the ELF segments to memory */
        ret = rproc_load_segments(rproc, fw);
        if (ret) {
                dev_err(dev, "Failed to load program segments: %d\n", ret);
                return ret;
        }

        /*
         * The starting device has been given the rproc->cached_table as the
         * resource table. The address of the vring along with the other
         * allocated resources (carveouts etc) is stored in cached_table.
         * In order to pass this information to the remote device we must copy
         * this information to device memory. We also update the table_ptr so
         * that any subsequent changes will be applied to the loaded version.
         */
        loaded_table = rproc_find_loaded_rsc_table(rproc, fw);
        if (loaded_table) {
                memcpy(loaded_table, rproc->cached_table, rproc->table_sz);
                rproc->table_ptr = loaded_table;
        }

        ret = rproc_prepare_subdevices(rproc);
        if (ret) {
                dev_err(dev, "failed to prepare subdevices for %s: %d\n",
                        rproc->name, ret);
                goto reset_table_ptr;
        }

        /* power up the remote processor */
        ret = rproc->ops->start(rproc);
        if (ret) {
                dev_err(dev, "can't start rproc %s: %d\n", rproc->name, ret);
                goto unprepare_subdevices;
        }

        /* Start any subdevices for the remote processor */
        ret = rproc_start_subdevices(rproc);
        if (ret) {
                dev_err(dev, "failed to probe subdevices for %s: %d\n",
                        rproc->name, ret);
                goto stop_rproc;
        }

        rproc->state = RPROC_RUNNING;

        dev_info(dev, "remote processor %s is now up\n", rproc->name);

        return 0;

stop_rproc:
        rproc->ops->stop(rproc);
unprepare_subdevices:
        rproc_unprepare_subdevices(rproc);
reset_table_ptr:
        rproc->table_ptr = rproc->cached_table;

        return ret;
}

static int rproc_attach(struct rproc *rproc)
{
        struct device *dev = &rproc->dev;
        int ret;

        ret = rproc_prepare_subdevices(rproc);
        if (ret) {
                dev_err(dev, "failed to prepare subdevices for %s: %d\n",
                        rproc->name, ret);
                goto out;
        }

        /* Attach to the remote processor */
        ret = rproc_attach_device(rproc);
        if (ret) {
                dev_err(dev, "can't attach to rproc %s: %d\n",
                        rproc->name, ret);
                goto unprepare_subdevices;
        }

        /* Start any subdevices for the remote processor */
        ret = rproc_start_subdevices(rproc);
        if (ret) {
                dev_err(dev, "failed to probe subdevices for %s: %d\n",
                        rproc->name, ret);
                goto stop_rproc;
        }

        rproc->state = RPROC_RUNNING;

        dev_info(dev, "remote processor %s is now attached\n", rproc->name);

        return 0;

stop_rproc:
        rproc->ops->stop(rproc);
unprepare_subdevices:
        rproc_unprepare_subdevices(rproc);
out:
        return ret;
}

/*
 * take a firmware and boot a remote processor with it.
 */
static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
{
        struct device *dev = &rproc->dev;
        const char *name = rproc->firmware;
        int ret;

        ret = rproc_fw_sanity_check(rproc, fw);
        if (ret)
                return ret;

        dev_info(dev, "Booting fw image %s, size %zd\n", name, fw->size);

        /*
         * if enabling an IOMMU isn't relevant for this rproc, this is
         * just a nop
         */
        ret = rproc_enable_iommu(rproc);
        if (ret) {
                dev_err(dev, "can't enable iommu: %d\n", ret);
                return ret;
        }

        /* Prepare rproc for firmware loading if needed */
        ret = rproc_prepare_device(rproc);
        if (ret) {
                dev_err(dev, "can't prepare rproc %s: %d\n", rproc->name, ret);
                goto disable_iommu;
        }

        rproc->bootaddr = rproc_get_boot_addr(rproc, fw);

        /* Load resource table, core dump segment list etc from the firmware */
        ret = rproc_parse_fw(rproc, fw);
        if (ret)
                goto unprepare_rproc;

        /* reset max_notifyid */
        rproc->max_notifyid = -1;

        /* reset handled vdev */
        rproc->nb_vdev = 0;

        /* handle fw resources which are required to boot rproc */
        ret = rproc_handle_resources(rproc, rproc_loading_handlers);
        if (ret) {
                dev_err(dev, "Failed to process resources: %d\n", ret);
                goto clean_up_resources;
        }

        /* Allocate carveout resources associated to rproc */
        ret = rproc_alloc_registered_carveouts(rproc);
        if (ret) {
                dev_err(dev, "Failed to allocate associated carveouts: %d\n",
                        ret);
                goto clean_up_resources;
        }

        ret = rproc_start(rproc, fw);
        if (ret)
                goto clean_up_resources;

        return 0;

clean_up_resources:
        rproc_resource_cleanup(rproc);
        kfree(rproc->cached_table);
        rproc->cached_table = NULL;
        rproc->table_ptr = NULL;
unprepare_rproc:
        /* release HW resources if needed */
        rproc_unprepare_device(rproc);
disable_iommu:
        rproc_disable_iommu(rproc);
        return ret;
}

static int rproc_set_rsc_table(struct rproc *rproc)
{
        struct resource_table *table_ptr;
        struct device *dev = &rproc->dev;
        size_t table_sz;
        int ret;

        table_ptr = rproc_get_loaded_rsc_table(rproc, &table_sz);
        if (!table_ptr) {
                /* Not having a resource table is acceptable */
                return 0;
        }

        if (IS_ERR(table_ptr)) {
                ret = PTR_ERR(table_ptr);
                dev_err(dev, "can't load resource table: %d\n", ret);
                return ret;
        }

        rproc->cached_table = NULL;
        rproc->table_ptr = table_ptr;
        rproc->table_sz = table_sz;

        return 0;
}

/*
 * Attach to remote processor - similar to rproc_fw_boot() but without
 * the steps that deal with the firmware image.
 */
static int rproc_actuate(struct rproc *rproc)
{
        struct device *dev = &rproc->dev;
        int ret;

        /*
         * if enabling an IOMMU isn't relevant for this rproc, this is
         * just a nop
         */
        ret = rproc_enable_iommu(rproc);
        if (ret) {
                dev_err(dev, "can't enable iommu: %d\n", ret);
                return ret;
        }

        ret = rproc_set_rsc_table(rproc);
        if (ret) {
                dev_err(dev, "can't load resource table: %d\n", ret);
                goto disable_iommu;
        }

        /* reset max_notifyid */
        rproc->max_notifyid = -1;

        /* reset handled vdev */
        rproc->nb_vdev = 0;

        /*
         * Handle firmware resources required to attach to a remote processor.
         * Because we are attaching rather than booting the remote processor,
         * we expect the platform driver to properly set rproc->table_ptr.
         */
        ret = rproc_handle_resources(rproc, rproc_loading_handlers);
        if (ret) {
                dev_err(dev, "Failed to process resources: %d\n", ret);
                goto disable_iommu;
        }

        /* Allocate carveout resources associated to rproc */
        ret = rproc_alloc_registered_carveouts(rproc);
        if (ret) {
                dev_err(dev, "Failed to allocate associated carveouts: %d\n",
                        ret);
                goto clean_up_resources;
        }

        ret = rproc_attach(rproc);
        if (ret)
                goto clean_up_resources;

        return 0;

clean_up_resources:
        rproc_resource_cleanup(rproc);
disable_iommu:
        rproc_disable_iommu(rproc);
        return ret;
}

/*
 * take a firmware and boot it up.
 *
 * Note: this function is called asynchronously upon registration of the
 * remote processor (so we must wait until it completes before we try
 * to unregister the device. one other option is just to use kref here,
 * that might be cleaner).
 */
static void rproc_auto_boot_callback(const struct firmware *fw, void *context)
{
        struct rproc *rproc = context;

        rproc_boot(rproc);

        release_firmware(fw);
}

static int rproc_trigger_auto_boot(struct rproc *rproc)
{
        int ret;

        /*
         * Since the remote processor is in a detached state, it has already
         * been booted by another entity.  As such there is no point in waiting
         * for a firmware image to be loaded, we can simply initiate the process
         * of attaching to it immediately.
         */
        if (rproc->state == RPROC_DETACHED)
                return rproc_boot(rproc);

        /*
         * We're initiating an asynchronous firmware loading, so we can
         * be built-in kernel code, without hanging the boot process.
         */
        ret = maybe_reject_firmware_nowait(THIS_MODULE, FW_ACTION_HOTPLUG,
                                      rproc->firmware, &rproc->dev, GFP_KERNEL,
                                      rproc, rproc_auto_boot_callback);
        if (ret < 0)
                dev_err(&rproc->dev, "request_firmware_nowait err: %d\n", ret);

        return ret;
}

static int rproc_stop(struct rproc *rproc, bool crashed)
{
        struct device *dev = &rproc->dev;
        int ret;

        /* Stop any subdevices for the remote processor */
        rproc_stop_subdevices(rproc, crashed);

        /* the installed resource table is no longer accessible */
        rproc->table_ptr = rproc->cached_table;

        /* power off the remote processor */
        ret = rproc->ops->stop(rproc);
        if (ret) {
                dev_err(dev, "can't stop rproc: %d\n", ret);
                return ret;
        }

        rproc_unprepare_subdevices(rproc);

        rproc->state = RPROC_OFFLINE;

        /*
         * The remote processor has been stopped and is now offline, which means
         * that the next time it is brought back online the remoteproc core will
         * be responsible to load its firmware.  As such it is no longer
         * autonomous.
         */
        rproc->autonomous = false;

        dev_info(dev, "stopped remote processor %s\n", rproc->name);

        return 0;
}


/**
 * rproc_trigger_recovery() - recover a remoteproc
 * @rproc: the remote processor
 *
 * The recovery is done by resetting all the virtio devices, that way all the
 * rpmsg drivers will be reseted along with the remote processor making the
 * remoteproc functional again.
 *
 * This function can sleep, so it cannot be called from atomic context.
 */
int rproc_trigger_recovery(struct rproc *rproc)
{
        const struct firmware *firmware_p;
        struct device *dev = &rproc->dev;
        int ret;

        ret = mutex_lock_interruptible(&rproc->lock);
        if (ret)
                return ret;

        /* State could have changed before we got the mutex */
        if (rproc->state != RPROC_CRASHED)
                goto unlock_mutex;

        dev_err(dev, "recovering %s\n", rproc->name);

        ret = rproc_stop(rproc, true);
        if (ret)
                goto unlock_mutex;

        /* generate coredump */
        rproc_coredump(rproc);

        /* load firmware */
        ret = maybe_reject_firmware(&firmware_p, rproc->firmware, dev);
        if (ret < 0) {
                dev_err(dev, "request_firmware failed: %d\n", ret);
                goto unlock_mutex;
        }

        /* boot the remote processor up again */
        ret = rproc_start(rproc, firmware_p);

        release_firmware(firmware_p);

unlock_mutex:
        mutex_unlock(&rproc->lock);
        return ret;
}

/**
 * rproc_crash_handler_work() - handle a crash
 * @work: work treating the crash
 *
 * This function needs to handle everything related to a crash, like cpu
 * registers and stack dump, information to help to debug the fatal error, etc.
 */
static void rproc_crash_handler_work(struct work_struct *work)
{
        struct rproc *rproc = container_of(work, struct rproc, crash_handler);
        struct device *dev = &rproc->dev;

        dev_dbg(dev, "enter %s\n", __func__);

        mutex_lock(&rproc->lock);

        if (rproc->state == RPROC_CRASHED) {
                /* handle only the first crash detected */
                mutex_unlock(&rproc->lock);
                return;
        }

        if (rproc->state == RPROC_OFFLINE) {
                /* Don't recover if the remote processor was stopped */
                mutex_unlock(&rproc->lock);
                goto out;
        }

        rproc->state = RPROC_CRASHED;
        dev_err(dev, "handling crash #%u in %s\n", ++rproc->crash_cnt,
                rproc->name);

        mutex_unlock(&rproc->lock);

        if (!rproc->recovery_disabled)
                rproc_trigger_recovery(rproc);

out:
        pm_relax(rproc->dev.parent);
}

/**
 * rproc_boot() - boot a remote processor
 * @rproc: handle of a remote processor
 *
 * Boot a remote processor (i.e. load its firmware, power it on, ...).
 *
 * If the remote processor is already powered on, this function immediately
 * returns (successfully).
 *
 * Returns 0 on success, and an appropriate error value otherwise.
 */
int rproc_boot(struct rproc *rproc)
{
        const struct firmware *firmware_p;
        struct device *dev;
        int ret;

        if (!rproc) {
                pr_err("invalid rproc handle\n");
                return -EINVAL;
        }

        dev = &rproc->dev;

        ret = mutex_lock_interruptible(&rproc->lock);
        if (ret) {
                dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, ret);
                return ret;
        }

        if (rproc->state == RPROC_DELETED) {
                ret = -ENODEV;
                dev_err(dev, "can't boot deleted rproc %s\n", rproc->name);
                goto unlock_mutex;
        }

        /* skip the boot or attach process if rproc is already powered up */
        if (atomic_inc_return(&rproc->power) > 1) {
                ret = 0;
                goto unlock_mutex;
        }

        if (rproc->state == RPROC_DETACHED) {
                dev_info(dev, "attaching to %s\n", rproc->name);

                ret = rproc_actuate(rproc);
        } else {
                dev_info(dev, "powering up %s\n", rproc->name);

                /* load firmware */
                ret = maybe_reject_firmware(&firmware_p, rproc->firmware, dev);
                if (ret < 0) {
                        dev_err(dev, "request_firmware failed: %d\n", ret);
                        goto downref_rproc;
                }

                ret = rproc_fw_boot(rproc, firmware_p);

                release_firmware(firmware_p);
        }

downref_rproc:
        if (ret)
                atomic_dec(&rproc->power);
unlock_mutex:
        mutex_unlock(&rproc->lock);
        return ret;
}
EXPORT_SYMBOL(rproc_boot);

/**
 * rproc_shutdown() - power off the remote processor
 * @rproc: the remote processor
 *
 * Power off a remote processor (previously booted with rproc_boot()).
 *
 * In case @rproc is still being used by an additional user(s), then
 * this function will just decrement the power refcount and exit,
 * without really powering off the device.
 *
 * Every call to rproc_boot() must (eventually) be accompanied by a call
 * to rproc_shutdown(). Calling rproc_shutdown() redundantly is a bug.
 *
 * Notes:
 * - we're not decrementing the rproc's refcount, only the power refcount.
 *   which means that the @rproc handle stays valid even after rproc_shutdown()
 *   returns, and users can still use it with a subsequent rproc_boot(), if
 *   needed.
 */
void rproc_shutdown(struct rproc *rproc)
{
        struct device *dev = &rproc->dev;
        int ret;

        ret = mutex_lock_interruptible(&rproc->lock);
        if (ret) {
                dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, ret);
                return;
        }

        /* if the remote proc is still needed, bail out */
        if (!atomic_dec_and_test(&rproc->power))
                goto out;

        ret = rproc_stop(rproc, false);
        if (ret) {
                atomic_inc(&rproc->power);
                goto out;
        }

        /* clean up all acquired resources */
        rproc_resource_cleanup(rproc);

        /* release HW resources if needed */
        rproc_unprepare_device(rproc);

        rproc_disable_iommu(rproc);

        /* Free the copy of the resource table */
        kfree(rproc->cached_table);
        rproc->cached_table = NULL;
        rproc->table_ptr = NULL;
out:
        mutex_unlock(&rproc->lock);
}
EXPORT_SYMBOL(rproc_shutdown);

/**
 * rproc_get_by_phandle() - find a remote processor by phandle
 * @phandle: phandle to the rproc
 *
 * Finds an rproc handle using the remote processor's phandle, and then
 * return a handle to the rproc.
 *
 * This function increments the remote processor's refcount, so always
 * use rproc_put() to decrement it back once rproc isn't needed anymore.
 *
 * Returns the rproc handle on success, and NULL on failure.
 */
#ifdef CONFIG_OF
struct rproc *rproc_get_by_phandle(phandle phandle)
{
        struct rproc *rproc = NULL, *r;
        struct device_node *np;

        np = of_find_node_by_phandle(phandle);
        if (!np)
                return NULL;

        rcu_read_lock();
        list_for_each_entry_rcu(r, &rproc_list, node) {
                if (r->dev.parent && r->dev.parent->of_node == np) {
                        /* prevent underlying implementation from being removed */
                        if (!try_module_get(r->dev.parent->driver->owner)) {
                                dev_err(&r->dev, "can't get owner\n");
                                break;
                        }

                        rproc = r;
                        get_device(&rproc->dev);
                        break;
                }
        }
        rcu_read_unlock();

        of_node_put(np);

        return rproc;
}
#else
struct rproc *rproc_get_by_phandle(phandle phandle)
{
        return NULL;
}
#endif
EXPORT_SYMBOL(rproc_get_by_phandle);

static int rproc_validate(struct rproc *rproc)
{
        switch (rproc->state) {
        case RPROC_OFFLINE:
                /*
                 * An offline processor without a start()
                 * function makes no sense.
                 */
                if (!rproc->ops->start)
                        return -EINVAL;
                break;
        case RPROC_DETACHED:
                /*
                 * A remote processor in a detached state without an
                 * attach() function makes not sense.
                 */
                if (!rproc->ops->attach)
                        return -EINVAL;
                /*
                 * When attaching to a remote processor the device memory
                 * is already available and as such there is no need to have a
                 * cached table.
                 */
                if (rproc->cached_table)
                        return -EINVAL;
                break;
        default:
                /*
                 * When adding a remote processor, the state of the device
                 * can be offline or detached, nothing else.
                 */
                return -EINVAL;
        }

        return 0;
}

/**
 * rproc_add() - register a remote processor
 * @rproc: the remote processor handle to register
 *
 * Registers @rproc with the remoteproc framework, after it has been
 * allocated with rproc_alloc().
 *
 * This is called by the platform-specific rproc implementation, whenever
 * a new remote processor device is probed.
 *
 * Returns 0 on success and an appropriate error code otherwise.
 *
 * Note: this function initiates an asynchronous firmware loading
 * context, which will look for virtio devices supported by the rproc's
 * firmware.
 *
 * If found, those virtio devices will be created and added, so as a result
 * of registering this remote processor, additional virtio drivers might be
 * probed.
 */
int rproc_add(struct rproc *rproc)
{
        struct device *dev = &rproc->dev;
        int ret;

        ret = device_add(dev);
        if (ret < 0)
                return ret;

        ret = rproc_validate(rproc);
        if (ret < 0)
                return ret;

        dev_info(dev, "%s is available\n", rproc->name);

        /* create debugfs entries */
        rproc_create_debug_dir(rproc);

        /* add char device for this remoteproc */
        ret = rproc_char_device_add(rproc);
        if (ret < 0)
                return ret;

        /*
         * Remind ourselves the remote processor has been attached to rather
         * than booted by the remoteproc core.  This is important because the
         * RPROC_DETACHED state will be lost as soon as the remote processor
         * has been attached to.  Used in firmware_show() and reset in
         * rproc_stop().
         */
        if (rproc->state == RPROC_DETACHED)
                rproc->autonomous = true;

        /* if rproc is marked always-on, request it to boot */
        if (rproc->auto_boot) {
                ret = rproc_trigger_auto_boot(rproc);
                if (ret < 0)
                        return ret;
        }

        /* expose to rproc_get_by_phandle users */
        mutex_lock(&rproc_list_mutex);
        list_add_rcu(&rproc->node, &rproc_list);
        mutex_unlock(&rproc_list_mutex);

        return 0;
}
EXPORT_SYMBOL(rproc_add);

static void devm_rproc_remove(void *rproc)
{
        rproc_del(rproc);
}

/**
 * devm_rproc_add() - resource managed rproc_add()
 * @dev: the underlying device
 * @rproc: the remote processor handle to register
 *
 * This function performs like rproc_add() but the registered rproc device will
 * automatically be removed on driver detach.
 *
 * Returns: 0 on success, negative errno on failure
 */
int devm_rproc_add(struct device *dev, struct rproc *rproc)
{
        int err;

        err = rproc_add(rproc);
        if (err)
                return err;

        return devm_add_action_or_reset(dev, devm_rproc_remove, rproc);
}
EXPORT_SYMBOL(devm_rproc_add);

/**
 * rproc_type_release() - release a remote processor instance
 * @dev: the rproc's device
 *
 * This function should _never_ be called directly.
 *
 * It will be called by the driver core when no one holds a valid pointer
 * to @dev anymore.
 */
static void rproc_type_release(struct device *dev)
{
        struct rproc *rproc = container_of(dev, struct rproc, dev);

        dev_info(&rproc->dev, "releasing %s\n", rproc->name);

        idr_destroy(&rproc->notifyids);

        if (rproc->index >= 0)
                ida_simple_remove(&rproc_dev_index, rproc->index);

        kfree_const(rproc->firmware);
        kfree_const(rproc->name);
        kfree(rproc->ops);
        kfree(rproc);
}

static const struct device_type rproc_type = {
        .name           = "remoteproc",
        .release        = rproc_type_release,
};

static int rproc_alloc_firmware(struct rproc *rproc,
                                const char *name, const char *firmware)
{
        const char *p;

        /*
         * Allocate a firmware name if the caller gave us one to work
         * with.  Otherwise construct a new one using a default pattern.
         */
        if (firmware)
                p = kstrdup_const(firmware, GFP_KERNEL);
        else
                p = kasprintf(GFP_KERNEL, "rproc-%s-fw", name);

        if (!p)
                return -ENOMEM;

        rproc->firmware = p;

        return 0;
}

static int rproc_alloc_ops(struct rproc *rproc, const struct rproc_ops *ops)
{
        rproc->ops = kmemdup(ops, sizeof(*ops), GFP_KERNEL);
        if (!rproc->ops)
                return -ENOMEM;

        if (rproc->ops->load)
                return 0;

        /* Default to ELF loader if no load function is specified */
        rproc->ops->load = rproc_elf_load_segments;
        rproc->ops->parse_fw = rproc_elf_load_rsc_table;
        rproc->ops->find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table;
        rproc->ops->sanity_check = rproc_elf_sanity_check;
        rproc->ops->get_boot_addr = rproc_elf_get_boot_addr;

        return 0;
}

/**
 * rproc_alloc() - allocate a remote processor handle
 * @dev: the underlying device
 * @name: name of this remote processor
 * @ops: platform-specific handlers (mainly start/stop)
 * @firmware: name of firmware file to load, can be NULL
 * @len: length of private data needed by the rproc driver (in bytes)
 *
 * Allocates a new remote processor handle, but does not register
 * it yet. if @firmware is NULL, a default name is used.
 *
 * This function should be used by rproc implementations during initialization
 * of the remote processor.
 *
 * After creating an rproc handle using this function, and when ready,
 * implementations should then call rproc_add() to complete
 * the registration of the remote processor.
 *
 * On success the new rproc is returned, and on failure, NULL.
 *
 * Note: _never_ directly deallocate @rproc, even if it was not registered
 * yet. Instead, when you need to unroll rproc_alloc(), use rproc_free().
 */
struct rproc *rproc_alloc(struct device *dev, const char *name,
                          const struct rproc_ops *ops,
                          const char *firmware, int len)
{
        struct rproc *rproc;

        if (!dev || !name || !ops)
                return NULL;

        rproc = kzalloc(sizeof(struct rproc) + len, GFP_KERNEL);
        if (!rproc)
                return NULL;

        rproc->priv = &rproc[1];
        rproc->auto_boot = true;
        rproc->elf_class = ELFCLASSNONE;
        rproc->elf_machine = EM_NONE;

        device_initialize(&rproc->dev);
        rproc->dev.parent = dev;
        rproc->dev.type = &rproc_type;
        rproc->dev.class = &rproc_class;
        rproc->dev.driver_data = rproc;
        idr_init(&rproc->notifyids);

        rproc->name = kstrdup_const(name, GFP_KERNEL);
        if (!rproc->name)
                goto put_device;

        if (rproc_alloc_firmware(rproc, name, firmware))
                goto put_device;

        if (rproc_alloc_ops(rproc, ops))
                goto put_device;

        /* Assign a unique device index and name */
        rproc->index = ida_simple_get(&rproc_dev_index, 0, 0, GFP_KERNEL);
        if (rproc->index < 0) {
                dev_err(dev, "ida_simple_get failed: %d\n", rproc->index);
                goto put_device;
        }

        dev_set_name(&rproc->dev, "remoteproc%d", rproc->index);

        atomic_set(&rproc->power, 0);

        mutex_init(&rproc->lock);

        INIT_LIST_HEAD(&rproc->carveouts);
        INIT_LIST_HEAD(&rproc->mappings);
        INIT_LIST_HEAD(&rproc->traces);
        INIT_LIST_HEAD(&rproc->rvdevs);
        INIT_LIST_HEAD(&rproc->subdevs);
        INIT_LIST_HEAD(&rproc->dump_segments);

        INIT_WORK(&rproc->crash_handler, rproc_crash_handler_work);

        rproc->state = RPROC_OFFLINE;

        return rproc;

put_device:
        put_device(&rproc->dev);
        return NULL;
}
EXPORT_SYMBOL(rproc_alloc);

/**
 * rproc_free() - unroll rproc_alloc()
 * @rproc: the remote processor handle
 *
 * This function decrements the rproc dev refcount.
 *
 * If no one holds any reference to rproc anymore, then its refcount would
 * now drop to zero, and it would be freed.
 */
void rproc_free(struct rproc *rproc)
{
        put_device(&rproc->dev);
}
EXPORT_SYMBOL(rproc_free);

/**
 * rproc_put() - release rproc reference
 * @rproc: the remote processor handle
 *
 * This function decrements the rproc dev refcount.
 *
 * If no one holds any reference to rproc anymore, then its refcount would
 * now drop to zero, and it would be freed.
 */
void rproc_put(struct rproc *rproc)
{
        module_put(rproc->dev.parent->driver->owner);
        put_device(&rproc->dev);
}
EXPORT_SYMBOL(rproc_put);

/**
 * rproc_del() - unregister a remote processor
 * @rproc: rproc handle to unregister
 *
 * This function should be called when the platform specific rproc
 * implementation decides to remove the rproc device. it should
 * _only_ be called if a previous invocation of rproc_add()
 * has completed successfully.
 *
 * After rproc_del() returns, @rproc isn't freed yet, because
 * of the outstanding reference created by rproc_alloc. To decrement that
 * one last refcount, one still needs to call rproc_free().
 *
 * Returns 0 on success and -EINVAL if @rproc isn't valid.
 */
int rproc_del(struct rproc *rproc)
{
        if (!rproc)
                return -EINVAL;

        /* if rproc is marked always-on, rproc_add() booted it */
        /* TODO: make sure this works with rproc->power > 1 */
        if (rproc->auto_boot)
                rproc_shutdown(rproc);

        mutex_lock(&rproc->lock);
        rproc->state = RPROC_DELETED;
        mutex_unlock(&rproc->lock);

        rproc_delete_debug_dir(rproc);

        /* the rproc is downref'ed as soon as it's removed from the klist */
        mutex_lock(&rproc_list_mutex);
        list_del_rcu(&rproc->node);
        mutex_unlock(&rproc_list_mutex);

        /* Ensure that no readers of rproc_list are still active */
        synchronize_rcu();

        device_del(&rproc->dev);
        rproc_char_device_remove(rproc);

        return 0;
}
EXPORT_SYMBOL(rproc_del);

static void devm_rproc_free(struct device *dev, void *res)
{
        rproc_free(*(struct rproc **)res);
}

/**
 * devm_rproc_alloc() - resource managed rproc_alloc()
 * @dev: the underlying device
 * @name: name of this remote processor
 * @ops: platform-specific handlers (mainly start/stop)
 * @firmware: name of firmware file to load, can be NULL
 * @len: length of private data needed by the rproc driver (in bytes)
 *
 * This function performs like rproc_alloc() but the acquired rproc device will
 * automatically be released on driver detach.
 *
 * Returns: new rproc instance, or NULL on failure
 */
struct rproc *devm_rproc_alloc(struct device *dev, const char *name,
                               const struct rproc_ops *ops,
                               const char *firmware, int len)
{
        struct rproc **ptr, *rproc;

        ptr = devres_alloc(devm_rproc_free, sizeof(*ptr), GFP_KERNEL);
        if (!ptr)
                return NULL;

        rproc = rproc_alloc(dev, name, ops, firmware, len);
        if (rproc) {
                *ptr = rproc;
                devres_add(dev, ptr);
        } else {
                devres_free(ptr);
        }

        return rproc;
}
EXPORT_SYMBOL(devm_rproc_alloc);

/**
 * rproc_add_subdev() - add a subdevice to a remoteproc
 * @rproc: rproc handle to add the subdevice to
 * @subdev: subdev handle to register
 *
 * Caller is responsible for populating optional subdevice function pointers.
 */
void rproc_add_subdev(struct rproc *rproc, struct rproc_subdev *subdev)
{
        list_add_tail(&subdev->node, &rproc->subdevs);
}
EXPORT_SYMBOL(rproc_add_subdev);

/**
 * rproc_remove_subdev() - remove a subdevice from a remoteproc
 * @rproc: rproc handle to remove the subdevice from
 * @subdev: subdev handle, previously registered with rproc_add_subdev()
 */
void rproc_remove_subdev(struct rproc *rproc, struct rproc_subdev *subdev)
{
        list_del(&subdev->node);
}
EXPORT_SYMBOL(rproc_remove_subdev);

/**
 * rproc_get_by_child() - acquire rproc handle of @dev's ancestor
 * @dev:        child device to find ancestor of
 *
 * Returns the ancestor rproc instance, or NULL if not found.
 */
struct rproc *rproc_get_by_child(struct device *dev)
{
        for (dev = dev->parent; dev; dev = dev->parent) {
                if (dev->type == &rproc_type)
                        return dev->driver_data;
        }

        return NULL;
}
EXPORT_SYMBOL(rproc_get_by_child);

/**
 * rproc_report_crash() - rproc crash reporter function
 * @rproc: remote processor
 * @type: crash type
 *
 * This function must be called every time a crash is detected by the low-level
 * drivers implementing a specific remoteproc. This should not be called from a
 * non-remoteproc driver.
 *
 * This function can be called from atomic/interrupt context.
 */
void rproc_report_crash(struct rproc *rproc, enum rproc_crash_type type)
{
        if (!rproc) {
                pr_err("NULL rproc pointer\n");
                return;
        }

        /* Prevent suspend while the remoteproc is being recovered */
        pm_stay_awake(rproc->dev.parent);

        dev_err(&rproc->dev, "crash detected in %s: type %s\n",
                rproc->name, rproc_crash_to_string(type));

        /* create a new task to handle the error */
        schedule_work(&rproc->crash_handler);
}
EXPORT_SYMBOL(rproc_report_crash);

static int rproc_panic_handler(struct notifier_block *nb, unsigned long event,
                               void *ptr)
{
        unsigned int longest = 0;
        struct rproc *rproc;
        unsigned int d;

        rcu_read_lock();
        list_for_each_entry_rcu(rproc, &rproc_list, node) {
                if (!rproc->ops->panic || rproc->state != RPROC_RUNNING)
                        continue;

                d = rproc->ops->panic(rproc);
                longest = max(longest, d);
        }
        rcu_read_unlock();

        /*
         * Delay for the longest requested duration before returning. This can
         * be used by the remoteproc drivers to give the remote processor time
         * to perform any requested operations (such as flush caches), when
         * it's not possible to signal the Linux side due to the panic.
         */
        mdelay(longest);

        return NOTIFY_DONE;
}

static void __init rproc_init_panic(void)
{
        rproc_panic_nb.notifier_call = rproc_panic_handler;
        atomic_notifier_chain_register(&panic_notifier_list, &rproc_panic_nb);
}

static void __exit rproc_exit_panic(void)
{
        atomic_notifier_chain_unregister(&panic_notifier_list, &rproc_panic_nb);
}

static int __init remoteproc_init(void)
{
        rproc_init_sysfs();
        rproc_init_debugfs();
        rproc_init_cdev();
        rproc_init_panic();

        return 0;
}
subsys_initcall(remoteproc_init);

static void __exit remoteproc_exit(void)
{
        ida_destroy(&rproc_dev_index);

        rproc_exit_panic();
        rproc_exit_debugfs();
        rproc_exit_sysfs();
}
module_exit(remoteproc_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Generic Remote Processor Framework");