GNU Linux-libre 4.9.328-gnu1

[releases.git] / drivers / usb / host / xhci-mem.c

/*
 * xHCI host controller driver
 *
 * Copyright (C) 2008 Intel Corp.
 *
 * Author: Sarah Sharp
 * Some code borrowed from the Linux EHCI driver.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/usb.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/dmapool.h>
#include <linux/dma-mapping.h>

#include "xhci.h"
#include "xhci-trace.h"

/*
 * Allocates a generic ring segment from the ring pool, sets the dma address,
 * initializes the segment to zero, and sets the private next pointer to NULL.
 *
 * Section 4.11.1.1:
 * "All components of all Command and Transfer TRBs shall be initialized to '0'"
 */
static struct xhci_segment *xhci_segment_alloc(struct xhci_hcd *xhci,
                                               unsigned int cycle_state,
                                               unsigned int max_packet,
                                               gfp_t flags)
{
        struct xhci_segment *seg;
        dma_addr_t      dma;
        int             i;

        seg = kzalloc(sizeof *seg, flags);
        if (!seg)
                return NULL;

        seg->trbs = dma_pool_zalloc(xhci->segment_pool, flags, &dma);
        if (!seg->trbs) {
                kfree(seg);
                return NULL;
        }

        if (max_packet) {
                seg->bounce_buf = kzalloc(max_packet, flags);
                if (!seg->bounce_buf) {
                        dma_pool_free(xhci->segment_pool, seg->trbs, dma);
                        kfree(seg);
                        return NULL;
                }
        }
        /* If the cycle state is 0, set the cycle bit to 1 for all the TRBs */
        if (cycle_state == 0) {
                for (i = 0; i < TRBS_PER_SEGMENT; i++)
                        seg->trbs[i].link.control |= cpu_to_le32(TRB_CYCLE);
        }
        seg->dma = dma;
        seg->next = NULL;

        return seg;
}

static void xhci_segment_free(struct xhci_hcd *xhci, struct xhci_segment *seg)
{
        if (seg->trbs) {
                dma_pool_free(xhci->segment_pool, seg->trbs, seg->dma);
                seg->trbs = NULL;
        }
        kfree(seg->bounce_buf);
        kfree(seg);
}

static void xhci_free_segments_for_ring(struct xhci_hcd *xhci,
                                struct xhci_segment *first)
{
        struct xhci_segment *seg;

        seg = first->next;
        while (seg != first) {
                struct xhci_segment *next = seg->next;
                xhci_segment_free(xhci, seg);
                seg = next;
        }
        xhci_segment_free(xhci, first);
}

/*
 * Make the prev segment point to the next segment.
 *
 * Change the last TRB in the prev segment to be a Link TRB which points to the
 * DMA address of the next segment.  The caller needs to set any Link TRB
 * related flags, such as End TRB, Toggle Cycle, and no snoop.
 */
static void xhci_link_segments(struct xhci_hcd *xhci, struct xhci_segment *prev,
                struct xhci_segment *next, enum xhci_ring_type type)
{
        u32 val;

        if (!prev || !next)
                return;
        prev->next = next;
        if (type != TYPE_EVENT) {
                prev->trbs[TRBS_PER_SEGMENT-1].link.segment_ptr =
                        cpu_to_le64(next->dma);

                /* Set the last TRB in the segment to have a TRB type ID of Link TRB */
                val = le32_to_cpu(prev->trbs[TRBS_PER_SEGMENT-1].link.control);
                val &= ~TRB_TYPE_BITMASK;
                val |= TRB_TYPE(TRB_LINK);
                /* Always set the chain bit with 0.95 hardware */
                /* Set chain bit for isoc rings on AMD 0.96 host */
                if (xhci_link_trb_quirk(xhci) ||
                                (type == TYPE_ISOC &&
                                 (xhci->quirks & XHCI_AMD_0x96_HOST)))
                        val |= TRB_CHAIN;
                prev->trbs[TRBS_PER_SEGMENT-1].link.control = cpu_to_le32(val);
        }
}

/*
 * Link the ring to the new segments.
 * Set Toggle Cycle for the new ring if needed.
 */
static void xhci_link_rings(struct xhci_hcd *xhci, struct xhci_ring *ring,
                struct xhci_segment *first, struct xhci_segment *last,
                unsigned int num_segs)
{
        struct xhci_segment *next;

        if (!ring || !first || !last)
                return;

        next = ring->enq_seg->next;
        xhci_link_segments(xhci, ring->enq_seg, first, ring->type);
        xhci_link_segments(xhci, last, next, ring->type);
        ring->num_segs += num_segs;
        ring->num_trbs_free += (TRBS_PER_SEGMENT - 1) * num_segs;

        if (ring->type != TYPE_EVENT && ring->enq_seg == ring->last_seg) {
                ring->last_seg->trbs[TRBS_PER_SEGMENT-1].link.control
                        &= ~cpu_to_le32(LINK_TOGGLE);
                last->trbs[TRBS_PER_SEGMENT-1].link.control
                        |= cpu_to_le32(LINK_TOGGLE);
                ring->last_seg = last;
        }
}

/*
 * We need a radix tree for mapping physical addresses of TRBs to which stream
 * ID they belong to.  We need to do this because the host controller won't tell
 * us which stream ring the TRB came from.  We could store the stream ID in an
 * event data TRB, but that doesn't help us for the cancellation case, since the
 * endpoint may stop before it reaches that event data TRB.
 *
 * The radix tree maps the upper portion of the TRB DMA address to a ring
 * segment that has the same upper portion of DMA addresses.  For example, say I
 * have segments of size 1KB, that are always 1KB aligned.  A segment may
 * start at 0x10c91000 and end at 0x10c913f0.  If I use the upper 10 bits, the
 * key to the stream ID is 0x43244.  I can use the DMA address of the TRB to
 * pass the radix tree a key to get the right stream ID:
 *
 *      0x10c90fff >> 10 = 0x43243
 *      0x10c912c0 >> 10 = 0x43244
 *      0x10c91400 >> 10 = 0x43245
 *
 * Obviously, only those TRBs with DMA addresses that are within the segment
 * will make the radix tree return the stream ID for that ring.
 *
 * Caveats for the radix tree:
 *
 * The radix tree uses an unsigned long as a key pair.  On 32-bit systems, an
 * unsigned long will be 32-bits; on a 64-bit system an unsigned long will be
 * 64-bits.  Since we only request 32-bit DMA addresses, we can use that as the
 * key on 32-bit or 64-bit systems (it would also be fine if we asked for 64-bit
 * PCI DMA addresses on a 64-bit system).  There might be a problem on 32-bit
 * extended systems (where the DMA address can be bigger than 32-bits),
 * if we allow the PCI dma mask to be bigger than 32-bits.  So don't do that.
 */
static int xhci_insert_segment_mapping(struct radix_tree_root *trb_address_map,
                struct xhci_ring *ring,
                struct xhci_segment *seg,
                gfp_t mem_flags)
{
        unsigned long key;
        int ret;

        key = (unsigned long)(seg->dma >> TRB_SEGMENT_SHIFT);
        /* Skip any segments that were already added. */
        if (radix_tree_lookup(trb_address_map, key))
                return 0;

        ret = radix_tree_maybe_preload(mem_flags);
        if (ret)
                return ret;
        ret = radix_tree_insert(trb_address_map,
                        key, ring);
        radix_tree_preload_end();
        return ret;
}

static void xhci_remove_segment_mapping(struct radix_tree_root *trb_address_map,
                struct xhci_segment *seg)
{
        unsigned long key;

        key = (unsigned long)(seg->dma >> TRB_SEGMENT_SHIFT);
        if (radix_tree_lookup(trb_address_map, key))
                radix_tree_delete(trb_address_map, key);
}

static int xhci_update_stream_segment_mapping(
                struct radix_tree_root *trb_address_map,
                struct xhci_ring *ring,
                struct xhci_segment *first_seg,
                struct xhci_segment *last_seg,
                gfp_t mem_flags)
{
        struct xhci_segment *seg;
        struct xhci_segment *failed_seg;
        int ret;

        if (WARN_ON_ONCE(trb_address_map == NULL))
                return 0;

        seg = first_seg;
        do {
                ret = xhci_insert_segment_mapping(trb_address_map,
                                ring, seg, mem_flags);
                if (ret)
                        goto remove_streams;
                if (seg == last_seg)
                        return 0;
                seg = seg->next;
        } while (seg != first_seg);

        return 0;

remove_streams:
        failed_seg = seg;
        seg = first_seg;
        do {
                xhci_remove_segment_mapping(trb_address_map, seg);
                if (seg == failed_seg)
                        return ret;
                seg = seg->next;
        } while (seg != first_seg);

        return ret;
}

static void xhci_remove_stream_mapping(struct xhci_ring *ring)
{
        struct xhci_segment *seg;

        if (WARN_ON_ONCE(ring->trb_address_map == NULL))
                return;

        seg = ring->first_seg;
        do {
                xhci_remove_segment_mapping(ring->trb_address_map, seg);
                seg = seg->next;
        } while (seg != ring->first_seg);
}

static int xhci_update_stream_mapping(struct xhci_ring *ring, gfp_t mem_flags)
{
        return xhci_update_stream_segment_mapping(ring->trb_address_map, ring,
                        ring->first_seg, ring->last_seg, mem_flags);
}

/* XXX: Do we need the hcd structure in all these functions? */
void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring)
{
        if (!ring)
                return;

        if (ring->first_seg) {
                if (ring->type == TYPE_STREAM)
                        xhci_remove_stream_mapping(ring);
                xhci_free_segments_for_ring(xhci, ring->first_seg);
        }

        kfree(ring);
}

static void xhci_initialize_ring_info(struct xhci_ring *ring,
                                        unsigned int cycle_state)
{
        /* The ring is empty, so the enqueue pointer == dequeue pointer */
        ring->enqueue = ring->first_seg->trbs;
        ring->enq_seg = ring->first_seg;
        ring->dequeue = ring->enqueue;
        ring->deq_seg = ring->first_seg;
        /* The ring is initialized to 0. The producer must write 1 to the cycle
         * bit to handover ownership of the TRB, so PCS = 1.  The consumer must
         * compare CCS to the cycle bit to check ownership, so CCS = 1.
         *
         * New rings are initialized with cycle state equal to 1; if we are
         * handling ring expansion, set the cycle state equal to the old ring.
         */
        ring->cycle_state = cycle_state;
        /* Not necessary for new rings, but needed for re-initialized rings */
        ring->enq_updates = 0;
        ring->deq_updates = 0;

        /*
         * Each segment has a link TRB, and leave an extra TRB for SW
         * accounting purpose
         */
        ring->num_trbs_free = ring->num_segs * (TRBS_PER_SEGMENT - 1) - 1;
}

/* Allocate segments and link them for a ring */
static int xhci_alloc_segments_for_ring(struct xhci_hcd *xhci,
                struct xhci_segment **first, struct xhci_segment **last,
                unsigned int num_segs, unsigned int cycle_state,
                enum xhci_ring_type type, unsigned int max_packet, gfp_t flags)
{
        struct xhci_segment *prev;

        prev = xhci_segment_alloc(xhci, cycle_state, max_packet, flags);
        if (!prev)
                return -ENOMEM;
        num_segs--;

        *first = prev;
        while (num_segs > 0) {
                struct xhci_segment     *next;

                next = xhci_segment_alloc(xhci, cycle_state, max_packet, flags);
                if (!next) {
                        prev = *first;
                        while (prev) {
                                next = prev->next;
                                xhci_segment_free(xhci, prev);
                                prev = next;
                        }
                        return -ENOMEM;
                }
                xhci_link_segments(xhci, prev, next, type);

                prev = next;
                num_segs--;
        }
        xhci_link_segments(xhci, prev, *first, type);
        *last = prev;

        return 0;
}

/**
 * Create a new ring with zero or more segments.
 *
 * Link each segment together into a ring.
 * Set the end flag and the cycle toggle bit on the last segment.
 * See section 4.9.1 and figures 15 and 16.
 */
static struct xhci_ring *xhci_ring_alloc(struct xhci_hcd *xhci,
                unsigned int num_segs, unsigned int cycle_state,
                enum xhci_ring_type type, unsigned int max_packet, gfp_t flags)
{
        struct xhci_ring        *ring;
        int ret;

        ring = kzalloc(sizeof *(ring), flags);
        if (!ring)
                return NULL;

        ring->num_segs = num_segs;
        ring->bounce_buf_len = max_packet;
        INIT_LIST_HEAD(&ring->td_list);
        ring->type = type;
        if (num_segs == 0)
                return ring;

        ret = xhci_alloc_segments_for_ring(xhci, &ring->first_seg,
                        &ring->last_seg, num_segs, cycle_state, type,
                        max_packet, flags);
        if (ret)
                goto fail;

        /* Only event ring does not use link TRB */
        if (type != TYPE_EVENT) {
                /* See section 4.9.2.1 and 6.4.4.1 */
                ring->last_seg->trbs[TRBS_PER_SEGMENT - 1].link.control |=
                        cpu_to_le32(LINK_TOGGLE);
        }
        xhci_initialize_ring_info(ring, cycle_state);
        return ring;

fail:
        kfree(ring);
        return NULL;
}

void xhci_free_or_cache_endpoint_ring(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                unsigned int ep_index)
{
        int rings_cached;

        rings_cached = virt_dev->num_rings_cached;
        if (rings_cached < XHCI_MAX_RINGS_CACHED) {
                virt_dev->ring_cache[rings_cached] =
                        virt_dev->eps[ep_index].ring;
                virt_dev->num_rings_cached++;
                xhci_dbg(xhci, "Cached old ring, "
                                "%d ring%s cached\n",
                                virt_dev->num_rings_cached,
                                (virt_dev->num_rings_cached > 1) ? "s" : "");
        } else {
                xhci_ring_free(xhci, virt_dev->eps[ep_index].ring);
                xhci_dbg(xhci, "Ring cache full (%d rings), "
                                "freeing ring\n",
                                virt_dev->num_rings_cached);
        }
        virt_dev->eps[ep_index].ring = NULL;
}

/* Zero an endpoint ring (except for link TRBs) and move the enqueue and dequeue
 * pointers to the beginning of the ring.
 */
static void xhci_reinit_cached_ring(struct xhci_hcd *xhci,
                        struct xhci_ring *ring, unsigned int cycle_state,
                        enum xhci_ring_type type)
{
        struct xhci_segment     *seg = ring->first_seg;
        int i;

        do {
                memset(seg->trbs, 0,
                                sizeof(union xhci_trb)*TRBS_PER_SEGMENT);
                if (cycle_state == 0) {
                        for (i = 0; i < TRBS_PER_SEGMENT; i++)
                                seg->trbs[i].link.control |=
                                        cpu_to_le32(TRB_CYCLE);
                }
                /* All endpoint rings have link TRBs */
                xhci_link_segments(xhci, seg, seg->next, type);
                seg = seg->next;
        } while (seg != ring->first_seg);
        ring->type = type;
        xhci_initialize_ring_info(ring, cycle_state);
        /* td list should be empty since all URBs have been cancelled,
         * but just in case...
         */
        INIT_LIST_HEAD(&ring->td_list);
}

/*
 * Expand an existing ring.
 * Look for a cached ring or allocate a new ring which has same segment numbers
 * and link the two rings.
 */
int xhci_ring_expansion(struct xhci_hcd *xhci, struct xhci_ring *ring,
                                unsigned int num_trbs, gfp_t flags)
{
        struct xhci_segment     *first;
        struct xhci_segment     *last;
        unsigned int            num_segs;
        unsigned int            num_segs_needed;
        int                     ret;

        num_segs_needed = (num_trbs + (TRBS_PER_SEGMENT - 1) - 1) /
                                (TRBS_PER_SEGMENT - 1);

        /* Allocate number of segments we needed, or double the ring size */
        num_segs = ring->num_segs > num_segs_needed ?
                        ring->num_segs : num_segs_needed;

        ret = xhci_alloc_segments_for_ring(xhci, &first, &last,
                        num_segs, ring->cycle_state, ring->type,
                        ring->bounce_buf_len, flags);
        if (ret)
                return -ENOMEM;

        if (ring->type == TYPE_STREAM)
                ret = xhci_update_stream_segment_mapping(ring->trb_address_map,
                                                ring, first, last, flags);
        if (ret) {
                struct xhci_segment *next;
                do {
                        next = first->next;
                        xhci_segment_free(xhci, first);
                        if (first == last)
                                break;
                        first = next;
                } while (true);
                return ret;
        }

        xhci_link_rings(xhci, ring, first, last, num_segs);
        xhci_dbg_trace(xhci, trace_xhci_dbg_ring_expansion,
                        "ring expansion succeed, now has %d segments",
                        ring->num_segs);

        return 0;
}

#define CTX_SIZE(_hcc) (HCC_64BYTE_CONTEXT(_hcc) ? 64 : 32)

static struct xhci_container_ctx *xhci_alloc_container_ctx(struct xhci_hcd *xhci,
                                                    int type, gfp_t flags)
{
        struct xhci_container_ctx *ctx;

        if ((type != XHCI_CTX_TYPE_DEVICE) && (type != XHCI_CTX_TYPE_INPUT))
                return NULL;

        ctx = kzalloc(sizeof(*ctx), flags);
        if (!ctx)
                return NULL;

        ctx->type = type;
        ctx->size = HCC_64BYTE_CONTEXT(xhci->hcc_params) ? 2048 : 1024;
        if (type == XHCI_CTX_TYPE_INPUT)
                ctx->size += CTX_SIZE(xhci->hcc_params);

        ctx->bytes = dma_pool_zalloc(xhci->device_pool, flags, &ctx->dma);
        if (!ctx->bytes) {
                kfree(ctx);
                return NULL;
        }
        return ctx;
}

static void xhci_free_container_ctx(struct xhci_hcd *xhci,
                             struct xhci_container_ctx *ctx)
{
        if (!ctx)
                return;
        dma_pool_free(xhci->device_pool, ctx->bytes, ctx->dma);
        kfree(ctx);
}

struct xhci_input_control_ctx *xhci_get_input_control_ctx(
                                              struct xhci_container_ctx *ctx)
{
        if (ctx->type != XHCI_CTX_TYPE_INPUT)
                return NULL;

        return (struct xhci_input_control_ctx *)ctx->bytes;
}

struct xhci_slot_ctx *xhci_get_slot_ctx(struct xhci_hcd *xhci,
                                        struct xhci_container_ctx *ctx)
{
        if (ctx->type == XHCI_CTX_TYPE_DEVICE)
                return (struct xhci_slot_ctx *)ctx->bytes;

        return (struct xhci_slot_ctx *)
                (ctx->bytes + CTX_SIZE(xhci->hcc_params));
}

struct xhci_ep_ctx *xhci_get_ep_ctx(struct xhci_hcd *xhci,
                                    struct xhci_container_ctx *ctx,
                                    unsigned int ep_index)
{
        /* increment ep index by offset of start of ep ctx array */
        ep_index++;
        if (ctx->type == XHCI_CTX_TYPE_INPUT)
                ep_index++;

        return (struct xhci_ep_ctx *)
                (ctx->bytes + (ep_index * CTX_SIZE(xhci->hcc_params)));
}


/***************** Streams structures manipulation *************************/

static void xhci_free_stream_ctx(struct xhci_hcd *xhci,
                unsigned int num_stream_ctxs,
                struct xhci_stream_ctx *stream_ctx, dma_addr_t dma)
{
        struct device *dev = xhci_to_hcd(xhci)->self.controller;
        size_t size = sizeof(struct xhci_stream_ctx) * num_stream_ctxs;

        if (size > MEDIUM_STREAM_ARRAY_SIZE)
                dma_free_coherent(dev, size,
                                stream_ctx, dma);
        else if (size <= SMALL_STREAM_ARRAY_SIZE)
                return dma_pool_free(xhci->small_streams_pool,
                                stream_ctx, dma);
        else
                return dma_pool_free(xhci->medium_streams_pool,
                                stream_ctx, dma);
}

/*
 * The stream context array for each endpoint with bulk streams enabled can
 * vary in size, based on:
 *  - how many streams the endpoint supports,
 *  - the maximum primary stream array size the host controller supports,
 *  - and how many streams the device driver asks for.
 *
 * The stream context array must be a power of 2, and can be as small as
 * 64 bytes or as large as 1MB.
 */
static struct xhci_stream_ctx *xhci_alloc_stream_ctx(struct xhci_hcd *xhci,
                unsigned int num_stream_ctxs, dma_addr_t *dma,
                gfp_t mem_flags)
{
        struct device *dev = xhci_to_hcd(xhci)->self.controller;
        size_t size = sizeof(struct xhci_stream_ctx) * num_stream_ctxs;

        if (size > MEDIUM_STREAM_ARRAY_SIZE)
                return dma_alloc_coherent(dev, size,
                                dma, mem_flags);
        else if (size <= SMALL_STREAM_ARRAY_SIZE)
                return dma_pool_alloc(xhci->small_streams_pool,
                                mem_flags, dma);
        else
                return dma_pool_alloc(xhci->medium_streams_pool,
                                mem_flags, dma);
}

struct xhci_ring *xhci_dma_to_transfer_ring(
                struct xhci_virt_ep *ep,
                u64 address)
{
        if (ep->ep_state & EP_HAS_STREAMS)
                return radix_tree_lookup(&ep->stream_info->trb_address_map,
                                address >> TRB_SEGMENT_SHIFT);
        return ep->ring;
}

struct xhci_ring *xhci_stream_id_to_ring(
                struct xhci_virt_device *dev,
                unsigned int ep_index,
                unsigned int stream_id)
{
        struct xhci_virt_ep *ep = &dev->eps[ep_index];

        if (stream_id == 0)
                return ep->ring;
        if (!ep->stream_info)
                return NULL;

        if (stream_id >= ep->stream_info->num_streams)
                return NULL;
        return ep->stream_info->stream_rings[stream_id];
}

/*
 * Change an endpoint's internal structure so it supports stream IDs.  The
 * number of requested streams includes stream 0, which cannot be used by device
 * drivers.
 *
 * The number of stream contexts in the stream context array may be bigger than
 * the number of streams the driver wants to use.  This is because the number of
 * stream context array entries must be a power of two.
 */
struct xhci_stream_info *xhci_alloc_stream_info(struct xhci_hcd *xhci,
                unsigned int num_stream_ctxs,
                unsigned int num_streams,
                unsigned int max_packet, gfp_t mem_flags)
{
        struct xhci_stream_info *stream_info;
        u32 cur_stream;
        struct xhci_ring *cur_ring;
        u64 addr;
        int ret;

        xhci_dbg(xhci, "Allocating %u streams and %u "
                        "stream context array entries.\n",
                        num_streams, num_stream_ctxs);
        if (xhci->cmd_ring_reserved_trbs == MAX_RSVD_CMD_TRBS) {
                xhci_dbg(xhci, "Command ring has no reserved TRBs available\n");
                return NULL;
        }
        xhci->cmd_ring_reserved_trbs++;

        stream_info = kzalloc(sizeof(struct xhci_stream_info), mem_flags);
        if (!stream_info)
                goto cleanup_trbs;

        stream_info->num_streams = num_streams;
        stream_info->num_stream_ctxs = num_stream_ctxs;

        /* Initialize the array of virtual pointers to stream rings. */
        stream_info->stream_rings = kzalloc(
                        sizeof(struct xhci_ring *)*num_streams,
                        mem_flags);
        if (!stream_info->stream_rings)
                goto cleanup_info;

        /* Initialize the array of DMA addresses for stream rings for the HW. */
        stream_info->stream_ctx_array = xhci_alloc_stream_ctx(xhci,
                        num_stream_ctxs, &stream_info->ctx_array_dma,
                        mem_flags);
        if (!stream_info->stream_ctx_array)
                goto cleanup_ctx;
        memset(stream_info->stream_ctx_array, 0,
                        sizeof(struct xhci_stream_ctx)*num_stream_ctxs);

        /* Allocate everything needed to free the stream rings later */
        stream_info->free_streams_command =
                xhci_alloc_command(xhci, true, true, mem_flags);
        if (!stream_info->free_streams_command)
                goto cleanup_ctx;

        INIT_RADIX_TREE(&stream_info->trb_address_map, GFP_ATOMIC);

        /* Allocate rings for all the streams that the driver will use,
         * and add their segment DMA addresses to the radix tree.
         * Stream 0 is reserved.
         */

        for (cur_stream = 1; cur_stream < num_streams; cur_stream++) {
                stream_info->stream_rings[cur_stream] =
                        xhci_ring_alloc(xhci, 2, 1, TYPE_STREAM, max_packet,
                                        mem_flags);
                cur_ring = stream_info->stream_rings[cur_stream];
                if (!cur_ring)
                        goto cleanup_rings;
                cur_ring->stream_id = cur_stream;
                cur_ring->trb_address_map = &stream_info->trb_address_map;
                /* Set deq ptr, cycle bit, and stream context type */
                addr = cur_ring->first_seg->dma |
                        SCT_FOR_CTX(SCT_PRI_TR) |
                        cur_ring->cycle_state;
                stream_info->stream_ctx_array[cur_stream].stream_ring =
                        cpu_to_le64(addr);
                xhci_dbg(xhci, "Setting stream %d ring ptr to 0x%08llx\n",
                                cur_stream, (unsigned long long) addr);

                ret = xhci_update_stream_mapping(cur_ring, mem_flags);
                if (ret) {
                        xhci_ring_free(xhci, cur_ring);
                        stream_info->stream_rings[cur_stream] = NULL;
                        goto cleanup_rings;
                }
        }
        /* Leave the other unused stream ring pointers in the stream context
         * array initialized to zero.  This will cause the xHC to give us an
         * error if the device asks for a stream ID we don't have setup (if it
         * was any other way, the host controller would assume the ring is
         * "empty" and wait forever for data to be queued to that stream ID).
         */

        return stream_info;

cleanup_rings:
        for (cur_stream = 1; cur_stream < num_streams; cur_stream++) {
                cur_ring = stream_info->stream_rings[cur_stream];
                if (cur_ring) {
                        xhci_ring_free(xhci, cur_ring);
                        stream_info->stream_rings[cur_stream] = NULL;
                }
        }
        xhci_free_command(xhci, stream_info->free_streams_command);
cleanup_ctx:
        kfree(stream_info->stream_rings);
cleanup_info:
        kfree(stream_info);
cleanup_trbs:
        xhci->cmd_ring_reserved_trbs--;
        return NULL;
}
/*
 * Sets the MaxPStreams field and the Linear Stream Array field.
 * Sets the dequeue pointer to the stream context array.
 */
void xhci_setup_streams_ep_input_ctx(struct xhci_hcd *xhci,
                struct xhci_ep_ctx *ep_ctx,
                struct xhci_stream_info *stream_info)
{
        u32 max_primary_streams;
        /* MaxPStreams is the number of stream context array entries, not the
         * number we're actually using.  Must be in 2^(MaxPstreams + 1) format.
         * fls(0) = 0, fls(0x1) = 1, fls(0x10) = 2, fls(0x100) = 3, etc.
         */
        max_primary_streams = fls(stream_info->num_stream_ctxs) - 2;
        xhci_dbg_trace(xhci,  trace_xhci_dbg_context_change,
                        "Setting number of stream ctx array entries to %u",
                        1 << (max_primary_streams + 1));
        ep_ctx->ep_info &= cpu_to_le32(~EP_MAXPSTREAMS_MASK);
        ep_ctx->ep_info |= cpu_to_le32(EP_MAXPSTREAMS(max_primary_streams)
                                       | EP_HAS_LSA);
        ep_ctx->deq  = cpu_to_le64(stream_info->ctx_array_dma);
}

/*
 * Sets the MaxPStreams field and the Linear Stream Array field to 0.
 * Reinstalls the "normal" endpoint ring (at its previous dequeue mark,
 * not at the beginning of the ring).
 */
void xhci_setup_no_streams_ep_input_ctx(struct xhci_ep_ctx *ep_ctx,
                struct xhci_virt_ep *ep)
{
        dma_addr_t addr;
        ep_ctx->ep_info &= cpu_to_le32(~(EP_MAXPSTREAMS_MASK | EP_HAS_LSA));
        addr = xhci_trb_virt_to_dma(ep->ring->deq_seg, ep->ring->dequeue);
        ep_ctx->deq  = cpu_to_le64(addr | ep->ring->cycle_state);
}

/* Frees all stream contexts associated with the endpoint,
 *
 * Caller should fix the endpoint context streams fields.
 */
void xhci_free_stream_info(struct xhci_hcd *xhci,
                struct xhci_stream_info *stream_info)
{
        int cur_stream;
        struct xhci_ring *cur_ring;

        if (!stream_info)
                return;

        for (cur_stream = 1; cur_stream < stream_info->num_streams;
                        cur_stream++) {
                cur_ring = stream_info->stream_rings[cur_stream];
                if (cur_ring) {
                        xhci_ring_free(xhci, cur_ring);
                        stream_info->stream_rings[cur_stream] = NULL;
                }
        }
        xhci_free_command(xhci, stream_info->free_streams_command);
        xhci->cmd_ring_reserved_trbs--;
        if (stream_info->stream_ctx_array)
                xhci_free_stream_ctx(xhci,
                                stream_info->num_stream_ctxs,
                                stream_info->stream_ctx_array,
                                stream_info->ctx_array_dma);

        kfree(stream_info->stream_rings);
        kfree(stream_info);
}


/***************** Device context manipulation *************************/

static void xhci_init_endpoint_timer(struct xhci_hcd *xhci,
                struct xhci_virt_ep *ep)
{
        setup_timer(&ep->stop_cmd_timer, xhci_stop_endpoint_command_watchdog,
                    (unsigned long)ep);
        ep->xhci = xhci;
}

static void xhci_free_tt_info(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                int slot_id)
{
        struct list_head *tt_list_head;
        struct xhci_tt_bw_info *tt_info, *next;
        bool slot_found = false;

        /* If the device never made it past the Set Address stage,
         * it may not have the real_port set correctly.
         */
        if (virt_dev->real_port == 0 ||
                        virt_dev->real_port > HCS_MAX_PORTS(xhci->hcs_params1)) {
                xhci_dbg(xhci, "Bad real port.\n");
                return;
        }

        tt_list_head = &(xhci->rh_bw[virt_dev->real_port - 1].tts);
        list_for_each_entry_safe(tt_info, next, tt_list_head, tt_list) {
                /* Multi-TT hubs will have more than one entry */
                if (tt_info->slot_id == slot_id) {
                        slot_found = true;
                        list_del(&tt_info->tt_list);
                        kfree(tt_info);
                } else if (slot_found) {
                        break;
                }
        }
}

int xhci_alloc_tt_info(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                struct usb_device *hdev,
                struct usb_tt *tt, gfp_t mem_flags)
{
        struct xhci_tt_bw_info          *tt_info;
        unsigned int                    num_ports;
        int                             i, j;

        if (!tt->multi)
                num_ports = 1;
        else
                num_ports = hdev->maxchild;

        for (i = 0; i < num_ports; i++, tt_info++) {
                struct xhci_interval_bw_table *bw_table;

                tt_info = kzalloc(sizeof(*tt_info), mem_flags);
                if (!tt_info)
                        goto free_tts;
                INIT_LIST_HEAD(&tt_info->tt_list);
                list_add(&tt_info->tt_list,
                                &xhci->rh_bw[virt_dev->real_port - 1].tts);
                tt_info->slot_id = virt_dev->udev->slot_id;
                if (tt->multi)
                        tt_info->ttport = i+1;
                bw_table = &tt_info->bw_table;
                for (j = 0; j < XHCI_MAX_INTERVAL; j++)
                        INIT_LIST_HEAD(&bw_table->interval_bw[j].endpoints);
        }
        return 0;

free_tts:
        xhci_free_tt_info(xhci, virt_dev, virt_dev->udev->slot_id);
        return -ENOMEM;
}


/* All the xhci_tds in the ring's TD list should be freed at this point.
 * Should be called with xhci->lock held if there is any chance the TT lists
 * will be manipulated by the configure endpoint, allocate device, or update
 * hub functions while this function is removing the TT entries from the list.
 */
void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id)
{
        struct xhci_virt_device *dev;
        int i;
        int old_active_eps = 0;

        /* Slot ID 0 is reserved */
        if (slot_id == 0 || !xhci->devs[slot_id])
                return;

        dev = xhci->devs[slot_id];
        xhci->dcbaa->dev_context_ptrs[slot_id] = 0;
        if (!dev)
                return;

        if (dev->tt_info)
                old_active_eps = dev->tt_info->active_eps;

        for (i = 0; i < 31; ++i) {
                if (dev->eps[i].ring)
                        xhci_ring_free(xhci, dev->eps[i].ring);
                if (dev->eps[i].stream_info)
                        xhci_free_stream_info(xhci,
                                        dev->eps[i].stream_info);
                /* Endpoints on the TT/root port lists should have been removed
                 * when usb_disable_device() was called for the device.
                 * We can't drop them anyway, because the udev might have gone
                 * away by this point, and we can't tell what speed it was.
                 */
                if (!list_empty(&dev->eps[i].bw_endpoint_list))
                        xhci_warn(xhci, "Slot %u endpoint %u "
                                        "not removed from BW list!\n",
                                        slot_id, i);
        }
        /* If this is a hub, free the TT(s) from the TT list */
        xhci_free_tt_info(xhci, dev, slot_id);
        /* If necessary, update the number of active TTs on this root port */
        xhci_update_tt_active_eps(xhci, dev, old_active_eps);

        if (dev->ring_cache) {
                for (i = 0; i < dev->num_rings_cached; i++)
                        xhci_ring_free(xhci, dev->ring_cache[i]);
                kfree(dev->ring_cache);
        }

        if (dev->in_ctx)
                xhci_free_container_ctx(xhci, dev->in_ctx);
        if (dev->out_ctx)
                xhci_free_container_ctx(xhci, dev->out_ctx);

        if (dev->udev && dev->udev->slot_id)
                dev->udev->slot_id = 0;
        kfree(xhci->devs[slot_id]);
        xhci->devs[slot_id] = NULL;
}

/*
 * Free a virt_device structure.
 * If the virt_device added a tt_info (a hub) and has children pointing to
 * that tt_info, then free the child first. Recursive.
 * We can't rely on udev at this point to find child-parent relationships.
 */
void xhci_free_virt_devices_depth_first(struct xhci_hcd *xhci, int slot_id)
{
        struct xhci_virt_device *vdev;
        struct list_head *tt_list_head;
        struct xhci_tt_bw_info *tt_info, *next;
        int i;

        vdev = xhci->devs[slot_id];
        if (!vdev)
                return;

        if (vdev->real_port == 0 ||
                        vdev->real_port > HCS_MAX_PORTS(xhci->hcs_params1)) {
                xhci_dbg(xhci, "Bad vdev->real_port.\n");
                goto out;
        }

        tt_list_head = &(xhci->rh_bw[vdev->real_port - 1].tts);
        list_for_each_entry_safe(tt_info, next, tt_list_head, tt_list) {
                /* is this a hub device that added a tt_info to the tts list */
                if (tt_info->slot_id == slot_id) {
                        /* are any devices using this tt_info? */
                        for (i = 1; i < HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
                                vdev = xhci->devs[i];
                                if (vdev && (vdev->tt_info == tt_info))
                                        xhci_free_virt_devices_depth_first(
                                                xhci, i);
                        }
                }
        }
out:
        /* we are now at a leaf device */
        xhci_free_virt_device(xhci, slot_id);
}

int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
                struct usb_device *udev, gfp_t flags)
{
        struct xhci_virt_device *dev;
        int i;

        /* Slot ID 0 is reserved */
        if (slot_id == 0 || xhci->devs[slot_id]) {
                xhci_warn(xhci, "Bad Slot ID %d\n", slot_id);
                return 0;
        }

        dev = kzalloc(sizeof(*dev), flags);
        if (!dev)
                return 0;

        /* Allocate the (output) device context that will be used in the HC. */
        dev->out_ctx = xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_DEVICE, flags);
        if (!dev->out_ctx)
                goto fail;

        xhci_dbg(xhci, "Slot %d output ctx = 0x%llx (dma)\n", slot_id,
                        (unsigned long long)dev->out_ctx->dma);

        /* Allocate the (input) device context for address device command */
        dev->in_ctx = xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_INPUT, flags);
        if (!dev->in_ctx)
                goto fail;

        xhci_dbg(xhci, "Slot %d input ctx = 0x%llx (dma)\n", slot_id,
                        (unsigned long long)dev->in_ctx->dma);

        /* Initialize the cancellation list and watchdog timers for each ep */
        for (i = 0; i < 31; i++) {
                xhci_init_endpoint_timer(xhci, &dev->eps[i]);
                INIT_LIST_HEAD(&dev->eps[i].cancelled_td_list);
                INIT_LIST_HEAD(&dev->eps[i].bw_endpoint_list);
        }

        /* Allocate endpoint 0 ring */
        dev->eps[0].ring = xhci_ring_alloc(xhci, 2, 1, TYPE_CTRL, 0, flags);
        if (!dev->eps[0].ring)
                goto fail;

        /* Allocate pointers to the ring cache */
        dev->ring_cache = kzalloc(
                        sizeof(struct xhci_ring *)*XHCI_MAX_RINGS_CACHED,
                        flags);
        if (!dev->ring_cache)
                goto fail;
        dev->num_rings_cached = 0;

        init_completion(&dev->cmd_completion);
        dev->udev = udev;

        /* Point to output device context in dcbaa. */
        xhci->dcbaa->dev_context_ptrs[slot_id] = cpu_to_le64(dev->out_ctx->dma);
        xhci_dbg(xhci, "Set slot id %d dcbaa entry %p to 0x%llx\n",
                 slot_id,
                 &xhci->dcbaa->dev_context_ptrs[slot_id],
                 le64_to_cpu(xhci->dcbaa->dev_context_ptrs[slot_id]));

        xhci->devs[slot_id] = dev;

        return 1;
fail:
        if (dev->eps[0].ring)
                xhci_ring_free(xhci, dev->eps[0].ring);
        if (dev->in_ctx)
                xhci_free_container_ctx(xhci, dev->in_ctx);
        if (dev->out_ctx)
                xhci_free_container_ctx(xhci, dev->out_ctx);
        kfree(dev);

        return 0;
}

void xhci_copy_ep0_dequeue_into_input_ctx(struct xhci_hcd *xhci,
                struct usb_device *udev)
{
        struct xhci_virt_device *virt_dev;
        struct xhci_ep_ctx      *ep0_ctx;
        struct xhci_ring        *ep_ring;

        virt_dev = xhci->devs[udev->slot_id];
        ep0_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, 0);
        ep_ring = virt_dev->eps[0].ring;
        /*
         * FIXME we don't keep track of the dequeue pointer very well after a
         * Set TR dequeue pointer, so we're setting the dequeue pointer of the
         * host to our enqueue pointer.  This should only be called after a
         * configured device has reset, so all control transfers should have
         * been completed or cancelled before the reset.
         */
        ep0_ctx->deq = cpu_to_le64(xhci_trb_virt_to_dma(ep_ring->enq_seg,
                                                        ep_ring->enqueue)
                                   | ep_ring->cycle_state);
}

/*
 * The xHCI roothub may have ports of differing speeds in any order in the port
 * status registers.  xhci->port_array provides an array of the port speed for
 * each offset into the port status registers.
 *
 * The xHCI hardware wants to know the roothub port number that the USB device
 * is attached to (or the roothub port its ancestor hub is attached to).  All we
 * know is the index of that port under either the USB 2.0 or the USB 3.0
 * roothub, but that doesn't give us the real index into the HW port status
 * registers. Call xhci_find_raw_port_number() to get real index.
 */
static u32 xhci_find_real_port_number(struct xhci_hcd *xhci,
                struct usb_device *udev)
{
        struct usb_device *top_dev;
        struct usb_hcd *hcd;

        if (udev->speed >= USB_SPEED_SUPER)
                hcd = xhci->shared_hcd;
        else
                hcd = xhci->main_hcd;

        for (top_dev = udev; top_dev->parent && top_dev->parent->parent;
                        top_dev = top_dev->parent)
                /* Found device below root hub */;

        return  xhci_find_raw_port_number(hcd, top_dev->portnum);
}

/* Setup an xHCI virtual device for a Set Address command */
int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *udev)
{
        struct xhci_virt_device *dev;
        struct xhci_ep_ctx      *ep0_ctx;
        struct xhci_slot_ctx    *slot_ctx;
        u32                     port_num;
        u32                     max_packets;
        struct usb_device *top_dev;

        dev = xhci->devs[udev->slot_id];
        /* Slot ID 0 is reserved */
        if (udev->slot_id == 0 || !dev) {
                xhci_warn(xhci, "Slot ID %d is not assigned to this device\n",
                                udev->slot_id);
                return -EINVAL;
        }
        ep0_ctx = xhci_get_ep_ctx(xhci, dev->in_ctx, 0);
        slot_ctx = xhci_get_slot_ctx(xhci, dev->in_ctx);

        /* 3) Only the control endpoint is valid - one endpoint context */
        slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(1) | udev->route);
        switch (udev->speed) {
        case USB_SPEED_SUPER_PLUS:
                slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_SSP);
                max_packets = MAX_PACKET(512);
                break;
        case USB_SPEED_SUPER:
                slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_SS);
                max_packets = MAX_PACKET(512);
                break;
        case USB_SPEED_HIGH:
                slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_HS);
                max_packets = MAX_PACKET(64);
                break;
        /* USB core guesses at a 64-byte max packet first for FS devices */
        case USB_SPEED_FULL:
                slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_FS);
                max_packets = MAX_PACKET(64);
                break;
        case USB_SPEED_LOW:
                slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_LS);
                max_packets = MAX_PACKET(8);
                break;
        case USB_SPEED_WIRELESS:
                xhci_dbg(xhci, "FIXME xHCI doesn't support wireless speeds\n");
                return -EINVAL;
                break;
        default:
                /* Speed was set earlier, this shouldn't happen. */
                return -EINVAL;
        }
        /* Find the root hub port this device is under */
        port_num = xhci_find_real_port_number(xhci, udev);
        if (!port_num)
                return -EINVAL;
        slot_ctx->dev_info2 |= cpu_to_le32(ROOT_HUB_PORT(port_num));
        /* Set the port number in the virtual_device to the faked port number */
        for (top_dev = udev; top_dev->parent && top_dev->parent->parent;
                        top_dev = top_dev->parent)
                /* Found device below root hub */;
        dev->fake_port = top_dev->portnum;
        dev->real_port = port_num;
        xhci_dbg(xhci, "Set root hub portnum to %d\n", port_num);
        xhci_dbg(xhci, "Set fake root hub portnum to %d\n", dev->fake_port);

        /* Find the right bandwidth table that this device will be a part of.
         * If this is a full speed device attached directly to a root port (or a
         * decendent of one), it counts as a primary bandwidth domain, not a
         * secondary bandwidth domain under a TT.  An xhci_tt_info structure
         * will never be created for the HS root hub.
         */
        if (!udev->tt || !udev->tt->hub->parent) {
                dev->bw_table = &xhci->rh_bw[port_num - 1].bw_table;
        } else {
                struct xhci_root_port_bw_info *rh_bw;
                struct xhci_tt_bw_info *tt_bw;

                rh_bw = &xhci->rh_bw[port_num - 1];
                /* Find the right TT. */
                list_for_each_entry(tt_bw, &rh_bw->tts, tt_list) {
                        if (tt_bw->slot_id != udev->tt->hub->slot_id)
                                continue;

                        if (!dev->udev->tt->multi ||
                                        (udev->tt->multi &&
                                         tt_bw->ttport == dev->udev->ttport)) {
                                dev->bw_table = &tt_bw->bw_table;
                                dev->tt_info = tt_bw;
                                break;
                        }
                }
                if (!dev->tt_info)
                        xhci_warn(xhci, "WARN: Didn't find a matching TT\n");
        }

        /* Is this a LS/FS device under an external HS hub? */
        if (udev->tt && udev->tt->hub->parent) {
                slot_ctx->tt_info = cpu_to_le32(udev->tt->hub->slot_id |
                                                (udev->ttport << 8));
                if (udev->tt->multi)
                        slot_ctx->dev_info |= cpu_to_le32(DEV_MTT);
        }
        xhci_dbg(xhci, "udev->tt = %p\n", udev->tt);
        xhci_dbg(xhci, "udev->ttport = 0x%x\n", udev->ttport);

        /* Step 4 - ring already allocated */
        /* Step 5 */
        ep0_ctx->ep_info2 = cpu_to_le32(EP_TYPE(CTRL_EP));

        /* EP 0 can handle "burst" sizes of 1, so Max Burst Size field is 0 */
        ep0_ctx->ep_info2 |= cpu_to_le32(MAX_BURST(0) | ERROR_COUNT(3) |
                                         max_packets);

        ep0_ctx->deq = cpu_to_le64(dev->eps[0].ring->first_seg->dma |
                                   dev->eps[0].ring->cycle_state);

        /* Steps 7 and 8 were done in xhci_alloc_virt_device() */

        return 0;
}

/*
 * Convert interval expressed as 2^(bInterval - 1) == interval into
 * straight exponent value 2^n == interval.
 *
 */
static unsigned int xhci_parse_exponent_interval(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        unsigned int interval;

        interval = clamp_val(ep->desc.bInterval, 1, 16) - 1;
        if (interval != ep->desc.bInterval - 1)
                dev_warn(&udev->dev,
                         "ep %#x - rounding interval to %d %sframes\n",
                         ep->desc.bEndpointAddress,
                         1 << interval,
                         udev->speed == USB_SPEED_FULL ? "" : "micro");

        if (udev->speed == USB_SPEED_FULL) {
                /*
                 * Full speed isoc endpoints specify interval in frames,
                 * not microframes. We are using microframes everywhere,
                 * so adjust accordingly.
                 */
                interval += 3;  /* 1 frame = 2^3 uframes */
        }

        return interval;
}

/*
 * Convert bInterval expressed in microframes (in 1-255 range) to exponent of
 * microframes, rounded down to nearest power of 2.
 */
static unsigned int xhci_microframes_to_exponent(struct usb_device *udev,
                struct usb_host_endpoint *ep, unsigned int desc_interval,
                unsigned int min_exponent, unsigned int max_exponent)
{
        unsigned int interval;

        interval = fls(desc_interval) - 1;
        interval = clamp_val(interval, min_exponent, max_exponent);
        if ((1 << interval) != desc_interval)
                dev_dbg(&udev->dev,
                         "ep %#x - rounding interval to %d microframes, ep desc says %d microframes\n",
                         ep->desc.bEndpointAddress,
                         1 << interval,
                         desc_interval);

        return interval;
}

static unsigned int xhci_parse_microframe_interval(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        if (ep->desc.bInterval == 0)
                return 0;
        return xhci_microframes_to_exponent(udev, ep,
                        ep->desc.bInterval, 0, 15);
}


static unsigned int xhci_parse_frame_interval(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        return xhci_microframes_to_exponent(udev, ep,
                        ep->desc.bInterval * 8, 3, 10);
}

/* Return the polling or NAK interval.
 *
 * The polling interval is expressed in "microframes".  If xHCI's Interval field
 * is set to N, it will service the endpoint every 2^(Interval)*125us.
 *
 * The NAK interval is one NAK per 1 to 255 microframes, or no NAKs if interval
 * is set to 0.
 */
static unsigned int xhci_get_endpoint_interval(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        unsigned int interval = 0;

        switch (udev->speed) {
        case USB_SPEED_HIGH:
                /* Max NAK rate */
                if (usb_endpoint_xfer_control(&ep->desc) ||
                    usb_endpoint_xfer_bulk(&ep->desc)) {
                        interval = xhci_parse_microframe_interval(udev, ep);
                        break;
                }
                /* Fall through - SS and HS isoc/int have same decoding */

        case USB_SPEED_SUPER_PLUS:
        case USB_SPEED_SUPER:
                if (usb_endpoint_xfer_int(&ep->desc) ||
                    usb_endpoint_xfer_isoc(&ep->desc)) {
                        interval = xhci_parse_exponent_interval(udev, ep);
                }
                break;

        case USB_SPEED_FULL:
                if (usb_endpoint_xfer_isoc(&ep->desc)) {
                        interval = xhci_parse_exponent_interval(udev, ep);
                        break;
                }
                /*
                 * Fall through for interrupt endpoint interval decoding
                 * since it uses the same rules as low speed interrupt
                 * endpoints.
                 */

        case USB_SPEED_LOW:
                if (usb_endpoint_xfer_int(&ep->desc) ||
                    usb_endpoint_xfer_isoc(&ep->desc)) {

                        interval = xhci_parse_frame_interval(udev, ep);
                }
                break;

        default:
                BUG();
        }
        return interval;
}

/* The "Mult" field in the endpoint context is only set for SuperSpeed isoc eps.
 * High speed endpoint descriptors can define "the number of additional
 * transaction opportunities per microframe", but that goes in the Max Burst
 * endpoint context field.
 */
static u32 xhci_get_endpoint_mult(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        if (udev->speed < USB_SPEED_SUPER ||
                        !usb_endpoint_xfer_isoc(&ep->desc))
                return 0;
        return ep->ss_ep_comp.bmAttributes;
}

static u32 xhci_get_endpoint_max_burst(struct usb_device *udev,
                                       struct usb_host_endpoint *ep)
{
        /* Super speed and Plus have max burst in ep companion desc */
        if (udev->speed >= USB_SPEED_SUPER)
                return ep->ss_ep_comp.bMaxBurst;

        if (udev->speed == USB_SPEED_HIGH &&
            (usb_endpoint_xfer_isoc(&ep->desc) ||
             usb_endpoint_xfer_int(&ep->desc)))
                return (usb_endpoint_maxp(&ep->desc) & 0x1800) >> 11;

        return 0;
}

static u32 xhci_get_endpoint_type(struct usb_host_endpoint *ep)
{
        int in;

        in = usb_endpoint_dir_in(&ep->desc);

        if (usb_endpoint_xfer_control(&ep->desc))
                return CTRL_EP;
        if (usb_endpoint_xfer_bulk(&ep->desc))
                return in ? BULK_IN_EP : BULK_OUT_EP;
        if (usb_endpoint_xfer_isoc(&ep->desc))
                return in ? ISOC_IN_EP : ISOC_OUT_EP;
        if (usb_endpoint_xfer_int(&ep->desc))
                return in ? INT_IN_EP : INT_OUT_EP;
        return 0;
}

/* Return the maximum endpoint service interval time (ESIT) payload.
 * Basically, this is the maxpacket size, multiplied by the burst size
 * and mult size.
 */
static u32 xhci_get_max_esit_payload(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        int max_burst;
        int max_packet;

        /* Only applies for interrupt or isochronous endpoints */
        if (usb_endpoint_xfer_control(&ep->desc) ||
                        usb_endpoint_xfer_bulk(&ep->desc))
                return 0;

        /* SuperSpeedPlus Isoc ep sending over 48k per esit */
        if ((udev->speed >= USB_SPEED_SUPER_PLUS) &&
            USB_SS_SSP_ISOC_COMP(ep->ss_ep_comp.bmAttributes))
                return le32_to_cpu(ep->ssp_isoc_ep_comp.dwBytesPerInterval);
        /* SuperSpeed or SuperSpeedPlus Isoc ep with less than 48k per esit */
        else if (udev->speed >= USB_SPEED_SUPER)
                return le16_to_cpu(ep->ss_ep_comp.wBytesPerInterval);

        max_packet = GET_MAX_PACKET(usb_endpoint_maxp(&ep->desc));
        max_burst = (usb_endpoint_maxp(&ep->desc) & 0x1800) >> 11;
        /* A 0 in max burst means 1 transfer per ESIT */
        return max_packet * (max_burst + 1);
}

/* Set up an endpoint with one ring segment.  Do not allocate stream rings.
 * Drivers will have to call usb_alloc_streams() to do that.
 */
int xhci_endpoint_init(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                struct usb_device *udev,
                struct usb_host_endpoint *ep,
                gfp_t mem_flags)
{
        unsigned int ep_index;
        struct xhci_ep_ctx *ep_ctx;
        struct xhci_ring *ep_ring;
        unsigned int max_packet;
        enum xhci_ring_type ring_type;
        u32 max_esit_payload;
        u32 endpoint_type;
        unsigned int max_burst;
        unsigned int interval;
        unsigned int mult;
        unsigned int avg_trb_len;
        unsigned int err_count = 0;

        ep_index = xhci_get_endpoint_index(&ep->desc);
        ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);

        endpoint_type = xhci_get_endpoint_type(ep);
        if (!endpoint_type)
                return -EINVAL;

        ring_type = usb_endpoint_type(&ep->desc);

        /*
         * Get values to fill the endpoint context, mostly from ep descriptor.
         * The average TRB buffer lengt for bulk endpoints is unclear as we
         * have no clue on scatter gather list entry size. For Isoc and Int,
         * set it to max available. See xHCI 1.1 spec 4.14.1.1 for details.
         */
        max_esit_payload = xhci_get_max_esit_payload(udev, ep);
        interval = xhci_get_endpoint_interval(udev, ep);

        /* Periodic endpoint bInterval limit quirk */
        if (usb_endpoint_xfer_int(&ep->desc) ||
            usb_endpoint_xfer_isoc(&ep->desc)) {
                if ((xhci->quirks & XHCI_LIMIT_ENDPOINT_INTERVAL_7) &&
                    udev->speed >= USB_SPEED_HIGH &&
                    interval >= 7) {
                        interval = 6;
                }
        }

        mult = xhci_get_endpoint_mult(udev, ep);
        max_packet = GET_MAX_PACKET(usb_endpoint_maxp(&ep->desc));
        max_burst = xhci_get_endpoint_max_burst(udev, ep);
        avg_trb_len = max_esit_payload;

        /* FIXME dig Mult and streams info out of ep companion desc */

        /* Allow 3 retries for everything but isoc, set CErr = 3 */
        if (!usb_endpoint_xfer_isoc(&ep->desc))
                err_count = 3;
        /* HS bulk max packet should be 512, FS bulk supports 8, 16, 32 or 64 */
        if (usb_endpoint_xfer_bulk(&ep->desc)) {
                if (udev->speed == USB_SPEED_HIGH)
                        max_packet = 512;
                if (udev->speed == USB_SPEED_FULL) {
                        max_packet = rounddown_pow_of_two(max_packet);
                        max_packet = clamp_val(max_packet, 8, 64);
                }
        }
        /* xHCI 1.0 and 1.1 indicates that ctrl ep avg TRB Length should be 8 */
        if (usb_endpoint_xfer_control(&ep->desc) && xhci->hci_version >= 0x100)
                avg_trb_len = 8;
        /* xhci 1.1 with LEC support doesn't use mult field, use RsvdZ */
        if ((xhci->hci_version > 0x100) && HCC2_LEC(xhci->hcc_params2))
                mult = 0;

        /* Set up the endpoint ring */
        virt_dev->eps[ep_index].new_ring =
                xhci_ring_alloc(xhci, 2, 1, ring_type, max_packet, mem_flags);
        if (!virt_dev->eps[ep_index].new_ring) {
                /* Attempt to use the ring cache */
                if (virt_dev->num_rings_cached == 0)
                        return -ENOMEM;
                virt_dev->num_rings_cached--;
                virt_dev->eps[ep_index].new_ring =
                        virt_dev->ring_cache[virt_dev->num_rings_cached];
                virt_dev->ring_cache[virt_dev->num_rings_cached] = NULL;
                xhci_reinit_cached_ring(xhci, virt_dev->eps[ep_index].new_ring,
                                        1, ring_type);
        }
        virt_dev->eps[ep_index].skip = false;
        ep_ring = virt_dev->eps[ep_index].new_ring;

        /* Fill the endpoint context */
        ep_ctx->ep_info = cpu_to_le32(EP_MAX_ESIT_PAYLOAD_HI(max_esit_payload) |
                                      EP_INTERVAL(interval) |
                                      EP_MULT(mult));
        ep_ctx->ep_info2 = cpu_to_le32(EP_TYPE(endpoint_type) |
                                       MAX_PACKET(max_packet) |
                                       MAX_BURST(max_burst) |
                                       ERROR_COUNT(err_count));
        ep_ctx->deq = cpu_to_le64(ep_ring->first_seg->dma |
                                  ep_ring->cycle_state);

        ep_ctx->tx_info = cpu_to_le32(EP_MAX_ESIT_PAYLOAD_LO(max_esit_payload) |
                                      EP_AVG_TRB_LENGTH(avg_trb_len));

        /* FIXME Debug endpoint context */
        return 0;
}

void xhci_endpoint_zero(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                struct usb_host_endpoint *ep)
{
        unsigned int ep_index;
        struct xhci_ep_ctx *ep_ctx;

        ep_index = xhci_get_endpoint_index(&ep->desc);
        ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);

        ep_ctx->ep_info = 0;
        ep_ctx->ep_info2 = 0;
        ep_ctx->deq = 0;
        ep_ctx->tx_info = 0;
        /* Don't free the endpoint ring until the set interface or configuration
         * request succeeds.
         */
}

void xhci_clear_endpoint_bw_info(struct xhci_bw_info *bw_info)
{
        bw_info->ep_interval = 0;
        bw_info->mult = 0;
        bw_info->num_packets = 0;
        bw_info->max_packet_size = 0;
        bw_info->type = 0;
        bw_info->max_esit_payload = 0;
}

void xhci_update_bw_info(struct xhci_hcd *xhci,
                struct xhci_container_ctx *in_ctx,
                struct xhci_input_control_ctx *ctrl_ctx,
                struct xhci_virt_device *virt_dev)
{
        struct xhci_bw_info *bw_info;
        struct xhci_ep_ctx *ep_ctx;
        unsigned int ep_type;
        int i;

        for (i = 1; i < 31; ++i) {
                bw_info = &virt_dev->eps[i].bw_info;

                /* We can't tell what endpoint type is being dropped, but
                 * unconditionally clearing the bandwidth info for non-periodic
                 * endpoints should be harmless because the info will never be
                 * set in the first place.
                 */
                if (!EP_IS_ADDED(ctrl_ctx, i) && EP_IS_DROPPED(ctrl_ctx, i)) {
                        /* Dropped endpoint */
                        xhci_clear_endpoint_bw_info(bw_info);
                        continue;
                }

                if (EP_IS_ADDED(ctrl_ctx, i)) {
                        ep_ctx = xhci_get_ep_ctx(xhci, in_ctx, i);
                        ep_type = CTX_TO_EP_TYPE(le32_to_cpu(ep_ctx->ep_info2));

                        /* Ignore non-periodic endpoints */
                        if (ep_type != ISOC_OUT_EP && ep_type != INT_OUT_EP &&
                                        ep_type != ISOC_IN_EP &&
                                        ep_type != INT_IN_EP)
                                continue;

                        /* Added or changed endpoint */
                        bw_info->ep_interval = CTX_TO_EP_INTERVAL(
                                        le32_to_cpu(ep_ctx->ep_info));
                        /* Number of packets and mult are zero-based in the
                         * input context, but we want one-based for the
                         * interval table.
                         */
                        bw_info->mult = CTX_TO_EP_MULT(
                                        le32_to_cpu(ep_ctx->ep_info)) + 1;
                        bw_info->num_packets = CTX_TO_MAX_BURST(
                                        le32_to_cpu(ep_ctx->ep_info2)) + 1;
                        bw_info->max_packet_size = MAX_PACKET_DECODED(
                                        le32_to_cpu(ep_ctx->ep_info2));
                        bw_info->type = ep_type;
                        bw_info->max_esit_payload = CTX_TO_MAX_ESIT_PAYLOAD(
                                        le32_to_cpu(ep_ctx->tx_info));
                }
        }
}

/* Copy output xhci_ep_ctx to the input xhci_ep_ctx copy.
 * Useful when you want to change one particular aspect of the endpoint and then
 * issue a configure endpoint command.
 */
void xhci_endpoint_copy(struct xhci_hcd *xhci,
                struct xhci_container_ctx *in_ctx,
                struct xhci_container_ctx *out_ctx,
                unsigned int ep_index)
{
        struct xhci_ep_ctx *out_ep_ctx;
        struct xhci_ep_ctx *in_ep_ctx;

        out_ep_ctx = xhci_get_ep_ctx(xhci, out_ctx, ep_index);
        in_ep_ctx = xhci_get_ep_ctx(xhci, in_ctx, ep_index);

        in_ep_ctx->ep_info = out_ep_ctx->ep_info;
        in_ep_ctx->ep_info2 = out_ep_ctx->ep_info2;
        in_ep_ctx->deq = out_ep_ctx->deq;
        in_ep_ctx->tx_info = out_ep_ctx->tx_info;
}

/* Copy output xhci_slot_ctx to the input xhci_slot_ctx.
 * Useful when you want to change one particular aspect of the endpoint and then
 * issue a configure endpoint command.  Only the context entries field matters,
 * but we'll copy the whole thing anyway.
 */
void xhci_slot_copy(struct xhci_hcd *xhci,
                struct xhci_container_ctx *in_ctx,
                struct xhci_container_ctx *out_ctx)
{
        struct xhci_slot_ctx *in_slot_ctx;
        struct xhci_slot_ctx *out_slot_ctx;

        in_slot_ctx = xhci_get_slot_ctx(xhci, in_ctx);
        out_slot_ctx = xhci_get_slot_ctx(xhci, out_ctx);

        in_slot_ctx->dev_info = out_slot_ctx->dev_info;
        in_slot_ctx->dev_info2 = out_slot_ctx->dev_info2;
        in_slot_ctx->tt_info = out_slot_ctx->tt_info;
        in_slot_ctx->dev_state = out_slot_ctx->dev_state;
}

/* Set up the scratchpad buffer array and scratchpad buffers, if needed. */
static int scratchpad_alloc(struct xhci_hcd *xhci, gfp_t flags)
{
        int i;
        struct device *dev = xhci_to_hcd(xhci)->self.controller;
        int num_sp = HCS_MAX_SCRATCHPAD(xhci->hcs_params2);

        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Allocating %d scratchpad buffers", num_sp);

        if (!num_sp)
                return 0;

        xhci->scratchpad = kzalloc(sizeof(*xhci->scratchpad), flags);
        if (!xhci->scratchpad)
                goto fail_sp;

        xhci->scratchpad->sp_array = dma_alloc_coherent(dev,
                                     num_sp * sizeof(u64),
                                     &xhci->scratchpad->sp_dma, flags);
        if (!xhci->scratchpad->sp_array)
                goto fail_sp2;

        xhci->scratchpad->sp_buffers = kzalloc(sizeof(void *) * num_sp, flags);
        if (!xhci->scratchpad->sp_buffers)
                goto fail_sp3;

        xhci->scratchpad->sp_dma_buffers =
                kzalloc(sizeof(dma_addr_t) * num_sp, flags);

        if (!xhci->scratchpad->sp_dma_buffers)
                goto fail_sp4;

        xhci->dcbaa->dev_context_ptrs[0] = cpu_to_le64(xhci->scratchpad->sp_dma);
        for (i = 0; i < num_sp; i++) {
                dma_addr_t dma;
                void *buf = dma_zalloc_coherent(dev, xhci->page_size, &dma,
                                flags);
                if (!buf)
                        goto fail_sp5;

                xhci->scratchpad->sp_array[i] = dma;
                xhci->scratchpad->sp_buffers[i] = buf;
                xhci->scratchpad->sp_dma_buffers[i] = dma;
        }

        return 0;

 fail_sp5:
        for (i = i - 1; i >= 0; i--) {
                dma_free_coherent(dev, xhci->page_size,
                                    xhci->scratchpad->sp_buffers[i],
                                    xhci->scratchpad->sp_dma_buffers[i]);
        }
        kfree(xhci->scratchpad->sp_dma_buffers);

 fail_sp4:
        kfree(xhci->scratchpad->sp_buffers);

 fail_sp3:
        dma_free_coherent(dev, num_sp * sizeof(u64),
                            xhci->scratchpad->sp_array,
                            xhci->scratchpad->sp_dma);

 fail_sp2:
        kfree(xhci->scratchpad);
        xhci->scratchpad = NULL;

 fail_sp:
        return -ENOMEM;
}

static void scratchpad_free(struct xhci_hcd *xhci)
{
        int num_sp;
        int i;
        struct device *dev = xhci_to_hcd(xhci)->self.controller;

        if (!xhci->scratchpad)
                return;

        num_sp = HCS_MAX_SCRATCHPAD(xhci->hcs_params2);

        for (i = 0; i < num_sp; i++) {
                dma_free_coherent(dev, xhci->page_size,
                                    xhci->scratchpad->sp_buffers[i],
                                    xhci->scratchpad->sp_dma_buffers[i]);
        }
        kfree(xhci->scratchpad->sp_dma_buffers);
        kfree(xhci->scratchpad->sp_buffers);
        dma_free_coherent(dev, num_sp * sizeof(u64),
                            xhci->scratchpad->sp_array,
                            xhci->scratchpad->sp_dma);
        kfree(xhci->scratchpad);
        xhci->scratchpad = NULL;
}

struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
                bool allocate_in_ctx, bool allocate_completion,
                gfp_t mem_flags)
{
        struct xhci_command *command;

        command = kzalloc(sizeof(*command), mem_flags);
        if (!command)
                return NULL;

        if (allocate_in_ctx) {
                command->in_ctx =
                        xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_INPUT,
                                        mem_flags);
                if (!command->in_ctx) {
                        kfree(command);
                        return NULL;
                }
        }

        if (allocate_completion) {
                command->completion =
                        kzalloc(sizeof(struct completion), mem_flags);
                if (!command->completion) {
                        xhci_free_container_ctx(xhci, command->in_ctx);
                        kfree(command);
                        return NULL;
                }
                init_completion(command->completion);
        }

        command->status = 0;
        INIT_LIST_HEAD(&command->cmd_list);
        return command;
}

void xhci_urb_free_priv(struct urb_priv *urb_priv)
{
        if (urb_priv) {
                kfree(urb_priv->td[0]);
                kfree(urb_priv);
        }
}

void xhci_free_command(struct xhci_hcd *xhci,
                struct xhci_command *command)
{
        xhci_free_container_ctx(xhci,
                        command->in_ctx);
        kfree(command->completion);
        kfree(command);
}

void xhci_mem_cleanup(struct xhci_hcd *xhci)
{
        struct device   *dev = xhci_to_hcd(xhci)->self.controller;
        int size;
        int i, j, num_ports;

        cancel_delayed_work_sync(&xhci->cmd_timer);

        /* Free the Event Ring Segment Table and the actual Event Ring */
        size = sizeof(struct xhci_erst_entry)*(xhci->erst.num_entries);
        if (xhci->erst.entries)
                dma_free_coherent(dev, size,
                                xhci->erst.entries, xhci->erst.erst_dma_addr);
        xhci->erst.entries = NULL;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed ERST");
        if (xhci->event_ring)
                xhci_ring_free(xhci, xhci->event_ring);
        xhci->event_ring = NULL;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed event ring");

        if (xhci->lpm_command)
                xhci_free_command(xhci, xhci->lpm_command);
        xhci->lpm_command = NULL;
        if (xhci->cmd_ring)
                xhci_ring_free(xhci, xhci->cmd_ring);
        xhci->cmd_ring = NULL;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed command ring");
        xhci_cleanup_command_queue(xhci);

        num_ports = HCS_MAX_PORTS(xhci->hcs_params1);
        for (i = 0; i < num_ports && xhci->rh_bw; i++) {
                struct xhci_interval_bw_table *bwt = &xhci->rh_bw[i].bw_table;
                for (j = 0; j < XHCI_MAX_INTERVAL; j++) {
                        struct list_head *ep = &bwt->interval_bw[j].endpoints;
                        while (!list_empty(ep))
                                list_del_init(ep->next);
                }
        }

        for (i = HCS_MAX_SLOTS(xhci->hcs_params1); i > 0; i--)
                xhci_free_virt_devices_depth_first(xhci, i);

        dma_pool_destroy(xhci->segment_pool);
        xhci->segment_pool = NULL;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed segment pool");

        dma_pool_destroy(xhci->device_pool);
        xhci->device_pool = NULL;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed device context pool");

        dma_pool_destroy(xhci->small_streams_pool);
        xhci->small_streams_pool = NULL;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Freed small stream array pool");

        dma_pool_destroy(xhci->medium_streams_pool);
        xhci->medium_streams_pool = NULL;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Freed medium stream array pool");

        if (xhci->dcbaa)
                dma_free_coherent(dev, sizeof(*xhci->dcbaa),
                                xhci->dcbaa, xhci->dcbaa->dma);
        xhci->dcbaa = NULL;

        scratchpad_free(xhci);

        if (!xhci->rh_bw)
                goto no_bw;

        for (i = 0; i < num_ports; i++) {
                struct xhci_tt_bw_info *tt, *n;
                list_for_each_entry_safe(tt, n, &xhci->rh_bw[i].tts, tt_list) {
                        list_del(&tt->tt_list);
                        kfree(tt);
                }
        }

no_bw:
        xhci->cmd_ring_reserved_trbs = 0;
        xhci->num_usb2_ports = 0;
        xhci->num_usb3_ports = 0;
        xhci->num_active_eps = 0;
        kfree(xhci->usb2_ports);
        kfree(xhci->usb3_ports);
        kfree(xhci->port_array);
        kfree(xhci->rh_bw);
        kfree(xhci->ext_caps);
        kfree(xhci->usb2_rhub.psi);
        kfree(xhci->usb3_rhub.psi);

        xhci->usb2_ports = NULL;
        xhci->usb3_ports = NULL;
        xhci->port_array = NULL;
        xhci->usb2_rhub.psi = NULL;
        xhci->usb3_rhub.psi = NULL;
        xhci->rh_bw = NULL;
        xhci->ext_caps = NULL;

        xhci->page_size = 0;
        xhci->page_shift = 0;
        xhci->bus_state[0].bus_suspended = 0;
        xhci->bus_state[1].bus_suspended = 0;
}

static int xhci_test_trb_in_td(struct xhci_hcd *xhci,
                struct xhci_segment *input_seg,
                union xhci_trb *start_trb,
                union xhci_trb *end_trb,
                dma_addr_t input_dma,
                struct xhci_segment *result_seg,
                char *test_name, int test_number)
{
        unsigned long long start_dma;
        unsigned long long end_dma;
        struct xhci_segment *seg;

        start_dma = xhci_trb_virt_to_dma(input_seg, start_trb);
        end_dma = xhci_trb_virt_to_dma(input_seg, end_trb);

        seg = trb_in_td(xhci, input_seg, start_trb, end_trb, input_dma, false);
        if (seg != result_seg) {
                xhci_warn(xhci, "WARN: %s TRB math test %d failed!\n",
                                test_name, test_number);
                xhci_warn(xhci, "Tested TRB math w/ seg %p and "
                                "input DMA 0x%llx\n",
                                input_seg,
                                (unsigned long long) input_dma);
                xhci_warn(xhci, "starting TRB %p (0x%llx DMA), "
                                "ending TRB %p (0x%llx DMA)\n",
                                start_trb, start_dma,
                                end_trb, end_dma);
                xhci_warn(xhci, "Expected seg %p, got seg %p\n",
                                result_seg, seg);
                trb_in_td(xhci, input_seg, start_trb, end_trb, input_dma,
                          true);
                return -1;
        }
        return 0;
}

/* TRB math checks for xhci_trb_in_td(), using the command and event rings. */
static int xhci_check_trb_in_td_math(struct xhci_hcd *xhci)
{
        struct {
                dma_addr_t              input_dma;
                struct xhci_segment     *result_seg;
        } simple_test_vector [] = {
                /* A zeroed DMA field should fail */
                { 0, NULL },
                /* One TRB before the ring start should fail */
                { xhci->event_ring->first_seg->dma - 16, NULL },
                /* One byte before the ring start should fail */
                { xhci->event_ring->first_seg->dma - 1, NULL },
                /* Starting TRB should succeed */
                { xhci->event_ring->first_seg->dma, xhci->event_ring->first_seg },
                /* Ending TRB should succeed */
                { xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT - 1)*16,
                        xhci->event_ring->first_seg },
                /* One byte after the ring end should fail */
                { xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT - 1)*16 + 1, NULL },
                /* One TRB after the ring end should fail */
                { xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT)*16, NULL },
                /* An address of all ones should fail */
                { (dma_addr_t) (~0), NULL },
        };
        struct {
                struct xhci_segment     *input_seg;
                union xhci_trb          *start_trb;
                union xhci_trb          *end_trb;
                dma_addr_t              input_dma;
                struct xhci_segment     *result_seg;
        } complex_test_vector [] = {
                /* Test feeding a valid DMA address from a different ring */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = xhci->event_ring->first_seg->trbs,
                        .end_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
                        .input_dma = xhci->cmd_ring->first_seg->dma,
                        .result_seg = NULL,
                },
                /* Test feeding a valid end TRB from a different ring */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = xhci->event_ring->first_seg->trbs,
                        .end_trb = &xhci->cmd_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
                        .input_dma = xhci->cmd_ring->first_seg->dma,
                        .result_seg = NULL,
                },
                /* Test feeding a valid start and end TRB from a different ring */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = xhci->cmd_ring->first_seg->trbs,
                        .end_trb = &xhci->cmd_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
                        .input_dma = xhci->cmd_ring->first_seg->dma,
                        .result_seg = NULL,
                },
                /* TRB in this ring, but after this TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[0],
                        .end_trb = &xhci->event_ring->first_seg->trbs[3],
                        .input_dma = xhci->event_ring->first_seg->dma + 4*16,
                        .result_seg = NULL,
                },
                /* TRB in this ring, but before this TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[3],
                        .end_trb = &xhci->event_ring->first_seg->trbs[6],
                        .input_dma = xhci->event_ring->first_seg->dma + 2*16,
                        .result_seg = NULL,
                },
                /* TRB in this ring, but after this wrapped TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 3],
                        .end_trb = &xhci->event_ring->first_seg->trbs[1],
                        .input_dma = xhci->event_ring->first_seg->dma + 2*16,
                        .result_seg = NULL,
                },
                /* TRB in this ring, but before this wrapped TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 3],
                        .end_trb = &xhci->event_ring->first_seg->trbs[1],
                        .input_dma = xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT - 4)*16,
                        .result_seg = NULL,
                },
                /* TRB not in this ring, and we have a wrapped TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 3],
                        .end_trb = &xhci->event_ring->first_seg->trbs[1],
                        .input_dma = xhci->cmd_ring->first_seg->dma + 2*16,
                        .result_seg = NULL,
                },
        };

        unsigned int num_tests;
        int i, ret;

        num_tests = ARRAY_SIZE(simple_test_vector);
        for (i = 0; i < num_tests; i++) {
                ret = xhci_test_trb_in_td(xhci,
                                xhci->event_ring->first_seg,
                                xhci->event_ring->first_seg->trbs,
                                &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
                                simple_test_vector[i].input_dma,
                                simple_test_vector[i].result_seg,
                                "Simple", i);
                if (ret < 0)
                        return ret;
        }

        num_tests = ARRAY_SIZE(complex_test_vector);
        for (i = 0; i < num_tests; i++) {
                ret = xhci_test_trb_in_td(xhci,
                                complex_test_vector[i].input_seg,
                                complex_test_vector[i].start_trb,
                                complex_test_vector[i].end_trb,
                                complex_test_vector[i].input_dma,
                                complex_test_vector[i].result_seg,
                                "Complex", i);
                if (ret < 0)
                        return ret;
        }
        xhci_dbg(xhci, "TRB math tests passed.\n");
        return 0;
}

static void xhci_set_hc_event_deq(struct xhci_hcd *xhci)
{
        u64 temp;
        dma_addr_t deq;

        deq = xhci_trb_virt_to_dma(xhci->event_ring->deq_seg,
                        xhci->event_ring->dequeue);
        if (deq == 0 && !in_interrupt())
                xhci_warn(xhci, "WARN something wrong with SW event ring "
                                "dequeue ptr.\n");
        /* Update HC event ring dequeue pointer */
        temp = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
        temp &= ERST_PTR_MASK;
        /* Don't clear the EHB bit (which is RW1C) because
         * there might be more events to service.
         */
        temp &= ~ERST_EHB;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Write event ring dequeue pointer, "
                        "preserving EHB bit");
        xhci_write_64(xhci, ((u64) deq & (u64) ~ERST_PTR_MASK) | temp,
                        &xhci->ir_set->erst_dequeue);
}

static void xhci_add_in_port(struct xhci_hcd *xhci, unsigned int num_ports,
                __le32 __iomem *addr, int max_caps)
{
        u32 temp, port_offset, port_count;
        int i;
        u8 major_revision, minor_revision;
        struct xhci_hub *rhub;

        temp = readl(addr);
        major_revision = XHCI_EXT_PORT_MAJOR(temp);
        minor_revision = XHCI_EXT_PORT_MINOR(temp);

        if (major_revision == 0x03) {
                rhub = &xhci->usb3_rhub;
                /*
                 * Some hosts incorrectly use sub-minor version for minor
                 * version (i.e. 0x02 instead of 0x20 for bcdUSB 0x320 and 0x01
                 * for bcdUSB 0x310). Since there is no USB release with sub
                 * minor version 0x301 to 0x309, we can assume that they are
                 * incorrect and fix it here.
                 */
                if (minor_revision > 0x00 && minor_revision < 0x10)
                        minor_revision <<= 4;
        } else if (major_revision <= 0x02) {
                rhub = &xhci->usb2_rhub;
        } else {
                xhci_warn(xhci, "Ignoring unknown port speed, "
                                "Ext Cap %p, revision = 0x%x\n",
                                addr, major_revision);
                /* Ignoring port protocol we can't understand. FIXME */
                return;
        }
        rhub->maj_rev = XHCI_EXT_PORT_MAJOR(temp);

        if (rhub->min_rev < minor_revision)
                rhub->min_rev = minor_revision;

        /* Port offset and count in the third dword, see section 7.2 */
        temp = readl(addr + 2);
        port_offset = XHCI_EXT_PORT_OFF(temp);
        port_count = XHCI_EXT_PORT_COUNT(temp);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Ext Cap %p, port offset = %u, "
                        "count = %u, revision = 0x%x",
                        addr, port_offset, port_count, major_revision);
        /* Port count includes the current port offset */
        if (port_offset == 0 || (port_offset + port_count - 1) > num_ports)
                /* WTF? "Valid values are ‘1’ to MaxPorts" */
                return;

        rhub->psi_count = XHCI_EXT_PORT_PSIC(temp);
        if (rhub->psi_count) {
                rhub->psi = kcalloc(rhub->psi_count, sizeof(*rhub->psi),
                                    GFP_KERNEL);
                if (!rhub->psi)
                        rhub->psi_count = 0;

                rhub->psi_uid_count++;
                for (i = 0; i < rhub->psi_count; i++) {
                        rhub->psi[i] = readl(addr + 4 + i);

                        /* count unique ID values, two consecutive entries can
                         * have the same ID if link is assymetric
                         */
                        if (i && (XHCI_EXT_PORT_PSIV(rhub->psi[i]) !=
                                  XHCI_EXT_PORT_PSIV(rhub->psi[i - 1])))
                                rhub->psi_uid_count++;

                        xhci_dbg(xhci, "PSIV:%d PSIE:%d PLT:%d PFD:%d LP:%d PSIM:%d\n",
                                  XHCI_EXT_PORT_PSIV(rhub->psi[i]),
                                  XHCI_EXT_PORT_PSIE(rhub->psi[i]),
                                  XHCI_EXT_PORT_PLT(rhub->psi[i]),
                                  XHCI_EXT_PORT_PFD(rhub->psi[i]),
                                  XHCI_EXT_PORT_LP(rhub->psi[i]),
                                  XHCI_EXT_PORT_PSIM(rhub->psi[i]));
                }
        }
        /* cache usb2 port capabilities */
        if (major_revision < 0x03 && xhci->num_ext_caps < max_caps)
                xhci->ext_caps[xhci->num_ext_caps++] = temp;

        /* Check the host's USB2 LPM capability */
        if ((xhci->hci_version == 0x96) && (major_revision != 0x03) &&
                        (temp & XHCI_L1C)) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                "xHCI 0.96: support USB2 software lpm");
                xhci->sw_lpm_support = 1;
        }

        if ((xhci->hci_version >= 0x100) && (major_revision != 0x03)) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                "xHCI 1.0: support USB2 software lpm");
                xhci->sw_lpm_support = 1;
                if (temp & XHCI_HLC) {
                        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                        "xHCI 1.0: support USB2 hardware lpm");
                        xhci->hw_lpm_support = 1;
                }
        }

        port_offset--;
        for (i = port_offset; i < (port_offset + port_count); i++) {
                /* Duplicate entry.  Ignore the port if the revisions differ. */
                if (xhci->port_array[i] != 0) {
                        xhci_warn(xhci, "Duplicate port entry, Ext Cap %p,"
                                        " port %u\n", addr, i);
                        xhci_warn(xhci, "Port was marked as USB %u, "
                                        "duplicated as USB %u\n",
                                        xhci->port_array[i], major_revision);
                        /* Only adjust the roothub port counts if we haven't
                         * found a similar duplicate.
                         */
                        if (xhci->port_array[i] != major_revision &&
                                xhci->port_array[i] != DUPLICATE_ENTRY) {
                                if (xhci->port_array[i] == 0x03)
                                        xhci->num_usb3_ports--;
                                else
                                        xhci->num_usb2_ports--;
                                xhci->port_array[i] = DUPLICATE_ENTRY;
                        }
                        /* FIXME: Should we disable the port? */
                        continue;
                }
                xhci->port_array[i] = major_revision;
                if (major_revision == 0x03)
                        xhci->num_usb3_ports++;
                else
                        xhci->num_usb2_ports++;
        }
        /* FIXME: Should we disable ports not in the Extended Capabilities? */
}

/*
 * Scan the Extended Capabilities for the "Supported Protocol Capabilities" that
 * specify what speeds each port is supposed to be.  We can't count on the port
 * speed bits in the PORTSC register being correct until a device is connected,
 * but we need to set up the two fake roothubs with the correct number of USB
 * 3.0 and USB 2.0 ports at host controller initialization time.
 */
static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
{
        void __iomem *base;
        u32 offset;
        unsigned int num_ports;
        int i, j, port_index;
        int cap_count = 0;
        u32 cap_start;

        num_ports = HCS_MAX_PORTS(xhci->hcs_params1);
        xhci->port_array = kzalloc(sizeof(*xhci->port_array)*num_ports, flags);
        if (!xhci->port_array)
                return -ENOMEM;

        xhci->rh_bw = kzalloc(sizeof(*xhci->rh_bw)*num_ports, flags);
        if (!xhci->rh_bw)
                return -ENOMEM;
        for (i = 0; i < num_ports; i++) {
                struct xhci_interval_bw_table *bw_table;

                INIT_LIST_HEAD(&xhci->rh_bw[i].tts);
                bw_table = &xhci->rh_bw[i].bw_table;
                for (j = 0; j < XHCI_MAX_INTERVAL; j++)
                        INIT_LIST_HEAD(&bw_table->interval_bw[j].endpoints);
        }
        base = &xhci->cap_regs->hc_capbase;

        cap_start = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_PROTOCOL);
        if (!cap_start) {
                xhci_err(xhci, "No Extended Capability registers, unable to set up roothub\n");
                return -ENODEV;
        }

        offset = cap_start;
        /* count extended protocol capability entries for later caching */
        while (offset) {
                cap_count++;
                offset = xhci_find_next_ext_cap(base, offset,
                                                      XHCI_EXT_CAPS_PROTOCOL);
        }

        xhci->ext_caps = kzalloc(sizeof(*xhci->ext_caps) * cap_count, flags);
        if (!xhci->ext_caps)
                return -ENOMEM;

        offset = cap_start;

        while (offset) {
                xhci_add_in_port(xhci, num_ports, base + offset, cap_count);
                if (xhci->num_usb2_ports + xhci->num_usb3_ports == num_ports)
                        break;
                offset = xhci_find_next_ext_cap(base, offset,
                                                XHCI_EXT_CAPS_PROTOCOL);
        }

        if (xhci->num_usb2_ports == 0 && xhci->num_usb3_ports == 0) {
                xhci_warn(xhci, "No ports on the roothubs?\n");
                return -ENODEV;
        }
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Found %u USB 2.0 ports and %u USB 3.0 ports.",
                        xhci->num_usb2_ports, xhci->num_usb3_ports);

        /* Place limits on the number of roothub ports so that the hub
         * descriptors aren't longer than the USB core will allocate.
         */
        if (xhci->num_usb3_ports > 15) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                "Limiting USB 3.0 roothub ports to 15.");
                xhci->num_usb3_ports = 15;
        }
        if (xhci->num_usb2_ports > USB_MAXCHILDREN) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                "Limiting USB 2.0 roothub ports to %u.",
                                USB_MAXCHILDREN);
                xhci->num_usb2_ports = USB_MAXCHILDREN;
        }

        /*
         * Note we could have all USB 3.0 ports, or all USB 2.0 ports.
         * Not sure how the USB core will handle a hub with no ports...
         */
        if (xhci->num_usb2_ports) {
                xhci->usb2_ports = kmalloc(sizeof(*xhci->usb2_ports)*
                                xhci->num_usb2_ports, flags);
                if (!xhci->usb2_ports)
                        return -ENOMEM;

                port_index = 0;
                for (i = 0; i < num_ports; i++) {
                        if (xhci->port_array[i] == 0x03 ||
                                        xhci->port_array[i] == 0 ||
                                        xhci->port_array[i] == DUPLICATE_ENTRY)
                                continue;

                        xhci->usb2_ports[port_index] =
                                &xhci->op_regs->port_status_base +
                                NUM_PORT_REGS*i;
                        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                        "USB 2.0 port at index %u, "
                                        "addr = %p", i,
                                        xhci->usb2_ports[port_index]);
                        port_index++;
                        if (port_index == xhci->num_usb2_ports)
                                break;
                }
        }
        if (xhci->num_usb3_ports) {
                xhci->usb3_ports = kmalloc(sizeof(*xhci->usb3_ports)*
                                xhci->num_usb3_ports, flags);
                if (!xhci->usb3_ports)
                        return -ENOMEM;

                port_index = 0;
                for (i = 0; i < num_ports; i++)
                        if (xhci->port_array[i] == 0x03) {
                                xhci->usb3_ports[port_index] =
                                        &xhci->op_regs->port_status_base +
                                        NUM_PORT_REGS*i;
                                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                                "USB 3.0 port at index %u, "
                                                "addr = %p", i,
                                                xhci->usb3_ports[port_index]);
                                port_index++;
                                if (port_index == xhci->num_usb3_ports)
                                        break;
                        }
        }
        return 0;
}

int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
{
        dma_addr_t      dma;
        struct device   *dev = xhci_to_hcd(xhci)->self.controller;
        unsigned int    val, val2;
        u64             val_64;
        struct xhci_segment     *seg;
        u32 page_size, temp;
        int i;

        INIT_LIST_HEAD(&xhci->cmd_list);

        /* init command timeout work */
        INIT_DELAYED_WORK(&xhci->cmd_timer, xhci_handle_command_timeout);
        init_completion(&xhci->cmd_ring_stop_completion);

        page_size = readl(&xhci->op_regs->page_size);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Supported page size register = 0x%x", page_size);
        for (i = 0; i < 16; i++) {
                if ((0x1 & page_size) != 0)
                        break;
                page_size = page_size >> 1;
        }
        if (i < 16)
                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Supported page size of %iK", (1 << (i+12)) / 1024);
        else
                xhci_warn(xhci, "WARN: no supported page size\n");
        /* Use 4K pages, since that's common and the minimum the HC supports */
        xhci->page_shift = 12;
        xhci->page_size = 1 << xhci->page_shift;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "HCD page size set to %iK", xhci->page_size / 1024);

        /*
         * Program the Number of Device Slots Enabled field in the CONFIG
         * register with the max value of slots the HC can handle.
         */
        val = HCS_MAX_SLOTS(readl(&xhci->cap_regs->hcs_params1));
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// xHC can handle at most %d device slots.", val);
        val2 = readl(&xhci->op_regs->config_reg);
        val |= (val2 & ~HCS_SLOTS_MASK);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Setting Max device slots reg = 0x%x.", val);
        writel(val, &xhci->op_regs->config_reg);

        /*
         * Section 5.4.8 - doorbell array must be
         * "physically contiguous and 64-byte (cache line) aligned".
         */
        xhci->dcbaa = dma_alloc_coherent(dev, sizeof(*xhci->dcbaa), &dma,
                        flags);
        if (!xhci->dcbaa)
                goto fail;
        memset(xhci->dcbaa, 0, sizeof *(xhci->dcbaa));
        xhci->dcbaa->dma = dma;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Device context base array address = 0x%llx (DMA), %p (virt)",
                        (unsigned long long)xhci->dcbaa->dma, xhci->dcbaa);
        xhci_write_64(xhci, dma, &xhci->op_regs->dcbaa_ptr);

        /*
         * Initialize the ring segment pool.  The ring must be a contiguous
         * structure comprised of TRBs.  The TRBs must be 16 byte aligned,
         * however, the command ring segment needs 64-byte aligned segments
         * and our use of dma addresses in the trb_address_map radix tree needs
         * TRB_SEGMENT_SIZE alignment, so we pick the greater alignment need.
         */
        xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
                        TRB_SEGMENT_SIZE, TRB_SEGMENT_SIZE, xhci->page_size);

        /* See Table 46 and Note on Figure 55 */
        xhci->device_pool = dma_pool_create("xHCI input/output contexts", dev,
                        2112, 64, xhci->page_size);
        if (!xhci->segment_pool || !xhci->device_pool)
                goto fail;

        /* Linear stream context arrays don't have any boundary restrictions,
         * and only need to be 16-byte aligned.
         */
        xhci->small_streams_pool =
                dma_pool_create("xHCI 256 byte stream ctx arrays",
                        dev, SMALL_STREAM_ARRAY_SIZE, 16, 0);
        xhci->medium_streams_pool =
                dma_pool_create("xHCI 1KB stream ctx arrays",
                        dev, MEDIUM_STREAM_ARRAY_SIZE, 16, 0);
        /* Any stream context array bigger than MEDIUM_STREAM_ARRAY_SIZE
         * will be allocated with dma_alloc_coherent()
         */

        if (!xhci->small_streams_pool || !xhci->medium_streams_pool)
                goto fail;

        /* Set up the command ring to have one segments for now. */
        xhci->cmd_ring = xhci_ring_alloc(xhci, 1, 1, TYPE_COMMAND, 0, flags);
        if (!xhci->cmd_ring)
                goto fail;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Allocated command ring at %p", xhci->cmd_ring);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "First segment DMA is 0x%llx",
                        (unsigned long long)xhci->cmd_ring->first_seg->dma);

        /* Set the address in the Command Ring Control register */
        val_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
        val_64 = (val_64 & (u64) CMD_RING_RSVD_BITS) |
                (xhci->cmd_ring->first_seg->dma & (u64) ~CMD_RING_RSVD_BITS) |
                xhci->cmd_ring->cycle_state;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Setting command ring address to 0x%016llx", val_64);
        xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
        xhci_dbg_cmd_ptrs(xhci);

        xhci->lpm_command = xhci_alloc_command(xhci, true, true, flags);
        if (!xhci->lpm_command)
                goto fail;

        /* Reserve one command ring TRB for disabling LPM.
         * Since the USB core grabs the shared usb_bus bandwidth mutex before
         * disabling LPM, we only need to reserve one TRB for all devices.
         */
        xhci->cmd_ring_reserved_trbs++;

        val = readl(&xhci->cap_regs->db_off);
        val &= DBOFF_MASK;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Doorbell array is located at offset 0x%x"
                        " from cap regs base addr", val);
        xhci->dba = (void __iomem *) xhci->cap_regs + val;
        xhci_dbg_regs(xhci);
        xhci_print_run_regs(xhci);
        /* Set ir_set to interrupt register set 0 */
        xhci->ir_set = &xhci->run_regs->ir_set[0];

        /*
         * Event ring setup: Allocate a normal ring, but also setup
         * the event ring segment table (ERST).  Section 4.9.3.
         */
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "// Allocating event ring");
        xhci->event_ring = xhci_ring_alloc(xhci, ERST_NUM_SEGS, 1, TYPE_EVENT,
                                        0, flags);
        if (!xhci->event_ring)
                goto fail;
        if (xhci_check_trb_in_td_math(xhci) < 0)
                goto fail;

        xhci->erst.entries = dma_alloc_coherent(dev,
                        sizeof(struct xhci_erst_entry) * ERST_NUM_SEGS, &dma,
                        flags);
        if (!xhci->erst.entries)
                goto fail;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Allocated event ring segment table at 0x%llx",
                        (unsigned long long)dma);

        memset(xhci->erst.entries, 0, sizeof(struct xhci_erst_entry)*ERST_NUM_SEGS);
        xhci->erst.num_entries = ERST_NUM_SEGS;
        xhci->erst.erst_dma_addr = dma;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Set ERST to 0; private num segs = %i, virt addr = %p, dma addr = 0x%llx",
                        xhci->erst.num_entries,
                        xhci->erst.entries,
                        (unsigned long long)xhci->erst.erst_dma_addr);

        /* set ring base address and size for each segment table entry */
        for (val = 0, seg = xhci->event_ring->first_seg; val < ERST_NUM_SEGS; val++) {
                struct xhci_erst_entry *entry = &xhci->erst.entries[val];
                entry->seg_addr = cpu_to_le64(seg->dma);
                entry->seg_size = cpu_to_le32(TRBS_PER_SEGMENT);
                entry->rsvd = 0;
                seg = seg->next;
        }

        /* set ERST count with the number of entries in the segment table */
        val = readl(&xhci->ir_set->erst_size);
        val &= ERST_SIZE_MASK;
        val |= ERST_NUM_SEGS;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Write ERST size = %i to ir_set 0 (some bits preserved)",
                        val);
        writel(val, &xhci->ir_set->erst_size);

        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Set ERST entries to point to event ring.");
        /* set the segment table base address */
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Set ERST base address for ir_set 0 = 0x%llx",
                        (unsigned long long)xhci->erst.erst_dma_addr);
        val_64 = xhci_read_64(xhci, &xhci->ir_set->erst_base);
        val_64 &= ERST_PTR_MASK;
        val_64 |= (xhci->erst.erst_dma_addr & (u64) ~ERST_PTR_MASK);
        xhci_write_64(xhci, val_64, &xhci->ir_set->erst_base);

        /* Set the event ring dequeue address */
        xhci_set_hc_event_deq(xhci);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Wrote ERST address to ir_set 0.");
        xhci_print_ir_set(xhci, 0);

        /*
         * XXX: Might need to set the Interrupter Moderation Register to
         * something other than the default (~1ms minimum between interrupts).
         * See section 5.5.1.2.
         */
        init_completion(&xhci->addr_dev);
        for (i = 0; i < MAX_HC_SLOTS; ++i)
                xhci->devs[i] = NULL;
        for (i = 0; i < USB_MAXCHILDREN; ++i) {
                xhci->bus_state[0].resume_done[i] = 0;
                xhci->bus_state[1].resume_done[i] = 0;
                /* Only the USB 2.0 completions will ever be used. */
                init_completion(&xhci->bus_state[1].rexit_done[i]);
        }

        if (scratchpad_alloc(xhci, flags))
                goto fail;
        if (xhci_setup_port_arrays(xhci, flags))
                goto fail;

        /* Enable USB 3.0 device notifications for function remote wake, which
         * is necessary for allowing USB 3.0 devices to do remote wakeup from
         * U3 (device suspend).
         */
        temp = readl(&xhci->op_regs->dev_notification);
        temp &= ~DEV_NOTE_MASK;
        temp |= DEV_NOTE_FWAKE;
        writel(temp, &xhci->op_regs->dev_notification);

        return 0;

fail:
        xhci_warn(xhci, "Couldn't initialize memory\n");
        xhci_halt(xhci);
        xhci_reset(xhci);
        xhci_mem_cleanup(xhci);
        return -ENOMEM;
}