// SPDX-License-Identifier: GPL-2.0
/*
 * xHCI host controller driver
 *
 * Copyright (C) 2008 Intel Corp.
 *
 * Author: Sarah Sharp
 * Some code borrowed from the Linux EHCI driver.
 */

/*
 * Ring initialization rules:
 * 1. Each segment is initialized to zero, except for link TRBs.
 * 2. Ring cycle state = 0.  This represents Producer Cycle State (PCS) or
 *    Consumer Cycle State (CCS), depending on ring function.
 * 3. Enqueue pointer = dequeue pointer = address of first TRB in the segment.
 *
 * Ring behavior rules:
 * 1. A ring is empty if enqueue == dequeue.  This means there will always be at
 *    least one free TRB in the ring.  This is useful if you want to turn that
 *    into a link TRB and expand the ring.
 * 2. When incrementing an enqueue or dequeue pointer, if the next TRB is a
 *    link TRB, then load the pointer with the address in the link TRB.  If the
 *    link TRB had its toggle bit set, you may need to update the ring cycle
 *    state (see cycle bit rules).  You may have to do this multiple times
 *    until you reach a non-link TRB.
 * 3. A ring is full if enqueue++ (for the definition of increment above)
 *    equals the dequeue pointer.
 *
 * Cycle bit rules:
 * 1. When a consumer increments a dequeue pointer and encounters a toggle bit
 *    in a link TRB, it must toggle the ring cycle state.
 * 2. When a producer increments an enqueue pointer and encounters a toggle bit
 *    in a link TRB, it must toggle the ring cycle state.
 *
 * Producer rules:
 * 1. Check if ring is full before you enqueue.
 * 2. Write the ring cycle state to the cycle bit in the TRB you're enqueuing.
 *    Update enqueue pointer between each write (which may update the ring
 *    cycle state).
 * 3. Notify consumer.  If SW is producer, it rings the doorbell for command
 *    and endpoint rings.  If HC is the producer for the event ring,
 *    and it generates an interrupt according to interrupt modulation rules.
 *
 * Consumer rules:
 * 1. Check if TRB belongs to you.  If the cycle bit == your ring cycle state,
 *    the TRB is owned by the consumer.
 * 2. Update dequeue pointer (which may update the ring cycle state) and
 *    continue processing TRBs until you reach a TRB which is not owned by you.
 * 3. Notify the producer.  SW is the consumer for the event ring, and it
 *   updates event ring dequeue pointer.  HC is the consumer for the command and
 *   endpoint rings; it generates events on the event ring for these.
 */

#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include "xhci.h"
#include "xhci-trace.h"

static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd,
                         u32 field1, u32 field2,
                         u32 field3, u32 field4, bool command_must_succeed);

/*
 * Returns zero if the TRB isn't in this segment, otherwise it returns the DMA
 * address of the TRB.
 */
dma_addr_t xhci_trb_virt_to_dma(struct xhci_segment *seg,
                union xhci_trb *trb)
{
        unsigned long segment_offset;

        if (!seg || !trb || trb < seg->trbs)
                return 0;
        /* offset in TRBs */
        segment_offset = trb - seg->trbs;
        if (segment_offset >= TRBS_PER_SEGMENT)
                return 0;
        return seg->dma + (segment_offset * sizeof(*trb));
}

static bool trb_is_noop(union xhci_trb *trb)
{
        return TRB_TYPE_NOOP_LE32(trb->generic.field[3]);
}

static bool trb_is_link(union xhci_trb *trb)
{
        return TRB_TYPE_LINK_LE32(trb->link.control);
}

static bool last_trb_on_seg(struct xhci_segment *seg, union xhci_trb *trb)
{
        return trb == &seg->trbs[TRBS_PER_SEGMENT - 1];
}

static bool last_trb_on_ring(struct xhci_ring *ring,
                        struct xhci_segment *seg, union xhci_trb *trb)
{
        return last_trb_on_seg(seg, trb) && (seg->next == ring->first_seg);
}

static bool link_trb_toggles_cycle(union xhci_trb *trb)
{
        return le32_to_cpu(trb->link.control) & LINK_TOGGLE;
}

static bool last_td_in_urb(struct xhci_td *td)
{
        struct urb_priv *urb_priv = td->urb->hcpriv;

        return urb_priv->num_tds_done == urb_priv->num_tds;
}

static void inc_td_cnt(struct urb *urb)
{
        struct urb_priv *urb_priv = urb->hcpriv;

        urb_priv->num_tds_done++;
}

static void trb_to_noop(union xhci_trb *trb, u32 noop_type)
{
        if (trb_is_link(trb)) {
                /* unchain chained link TRBs */
                trb->link.control &= cpu_to_le32(~TRB_CHAIN);
        } else {
                trb->generic.field[0] = 0;
                trb->generic.field[1] = 0;
                trb->generic.field[2] = 0;
                /* Preserve only the cycle bit of this TRB */
                trb->generic.field[3] &= cpu_to_le32(TRB_CYCLE);
                trb->generic.field[3] |= cpu_to_le32(TRB_TYPE(noop_type));
        }
}

/* Updates trb to point to the next TRB in the ring, and updates seg if the next
 * TRB is in a new segment.  This does not skip over link TRBs, and it does not
 * effect the ring dequeue or enqueue pointers.
 */
static void next_trb(struct xhci_hcd *xhci,
                struct xhci_ring *ring,
                struct xhci_segment **seg,
                union xhci_trb **trb)
{
        if (trb_is_link(*trb)) {
                *seg = (*seg)->next;
                *trb = ((*seg)->trbs);
        } else {
                (*trb)++;
        }
}

/*
 * See Cycle bit rules. SW is the consumer for the event ring only.
 */
void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring)
{
        unsigned int link_trb_count = 0;

        /* event ring doesn't have link trbs, check for last trb */
        if (ring->type == TYPE_EVENT) {
                if (!last_trb_on_seg(ring->deq_seg, ring->dequeue)) {
                        ring->dequeue++;
                        goto out;
                }
                if (last_trb_on_ring(ring, ring->deq_seg, ring->dequeue))
                        ring->cycle_state ^= 1;
                ring->deq_seg = ring->deq_seg->next;
                ring->dequeue = ring->deq_seg->trbs;
                goto out;
        }

        /* All other rings have link trbs */
        if (!trb_is_link(ring->dequeue)) {
                if (last_trb_on_seg(ring->deq_seg, ring->dequeue)) {
                        xhci_warn(xhci, "Missing link TRB at end of segment\n");
                } else {
                        ring->dequeue++;
                        ring->num_trbs_free++;
                }
        }

        while (trb_is_link(ring->dequeue)) {
                ring->deq_seg = ring->deq_seg->next;
                ring->dequeue = ring->deq_seg->trbs;

                if (link_trb_count++ > ring->num_segs) {
                        xhci_warn(xhci, "Ring is an endless link TRB loop\n");
                        break;
                }
        }
out:
        trace_xhci_inc_deq(ring);

        return;
}

/*
 * See Cycle bit rules. SW is the consumer for the event ring only.
 *
 * If we've just enqueued a TRB that is in the middle of a TD (meaning the
 * chain bit is set), then set the chain bit in all the following link TRBs.
 * If we've enqueued the last TRB in a TD, make sure the following link TRBs
 * have their chain bit cleared (so that each Link TRB is a separate TD).
 *
 * Section 6.4.4.1 of the 0.95 spec says link TRBs cannot have the chain bit
 * set, but other sections talk about dealing with the chain bit set.  This was
 * fixed in the 0.96 specification errata, but we have to assume that all 0.95
 * xHCI hardware can't handle the chain bit being cleared on a link TRB.
 *
 * @more_trbs_coming:   Will you enqueue more TRBs before calling
 *                      prepare_transfer()?
 */
static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring,
                        bool more_trbs_coming)
{
        u32 chain;
        union xhci_trb *next;
        unsigned int link_trb_count = 0;

        chain = le32_to_cpu(ring->enqueue->generic.field[3]) & TRB_CHAIN;
        /* If this is not event ring, there is one less usable TRB */
        if (!trb_is_link(ring->enqueue))
                ring->num_trbs_free--;

        if (last_trb_on_seg(ring->enq_seg, ring->enqueue)) {
                xhci_err(xhci, "Tried to move enqueue past ring segment\n");
                return;
        }

        next = ++(ring->enqueue);

        /* Update the dequeue pointer further if that was a link TRB */
        while (trb_is_link(next)) {

                /*
                 * If the caller doesn't plan on enqueueing more TDs before
                 * ringing the doorbell, then we don't want to give the link TRB
                 * to the hardware just yet. We'll give the link TRB back in
                 * prepare_ring() just before we enqueue the TD at the top of
                 * the ring.
                 */
                if (!chain && !more_trbs_coming)
                        break;

                /* If we're not dealing with 0.95 hardware or isoc rings on
                 * AMD 0.96 host, carry over the chain bit of the previous TRB
                 * (which may mean the chain bit is cleared).
                 */
                if (!(ring->type == TYPE_ISOC &&
                      (xhci->quirks & XHCI_AMD_0x96_HOST)) &&
                    !xhci_link_trb_quirk(xhci)) {
                        next->link.control &= cpu_to_le32(~TRB_CHAIN);
                        next->link.control |= cpu_to_le32(chain);
                }
                /* Give this link TRB to the hardware */
                wmb();
                next->link.control ^= cpu_to_le32(TRB_CYCLE);

                /* Toggle the cycle bit after the last ring segment. */
                if (link_trb_toggles_cycle(next))
                        ring->cycle_state ^= 1;

                ring->enq_seg = ring->enq_seg->next;
                ring->enqueue = ring->enq_seg->trbs;
                next = ring->enqueue;

                if (link_trb_count++ > ring->num_segs) {
                        xhci_warn(xhci, "%s: Ring link TRB loop\n", __func__);
                        break;
                }
        }

        trace_xhci_inc_enq(ring);
}

/*
 * Check to see if there's room to enqueue num_trbs on the ring and make sure
 * enqueue pointer will not advance into dequeue segment. See rules above.
 */
static inline int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring,
                unsigned int num_trbs)
{
        int num_trbs_in_deq_seg;

        if (ring->num_trbs_free < num_trbs)
                return 0;

        if (ring->type != TYPE_COMMAND && ring->type != TYPE_EVENT) {
                num_trbs_in_deq_seg = ring->dequeue - ring->deq_seg->trbs;
                if (ring->num_trbs_free < num_trbs + num_trbs_in_deq_seg)
                        return 0;
        }

        return 1;
}

/* Ring the host controller doorbell after placing a command on the ring */
void xhci_ring_cmd_db(struct xhci_hcd *xhci)
{
        if (!(xhci->cmd_ring_state & CMD_RING_STATE_RUNNING))
                return;

        xhci_dbg(xhci, "// Ding dong!\n");

        trace_xhci_ring_host_doorbell(0, DB_VALUE_HOST);

        writel(DB_VALUE_HOST, &xhci->dba->doorbell[0]);
        /* Flush PCI posted writes */
        readl(&xhci->dba->doorbell[0]);
}

static bool xhci_mod_cmd_timer(struct xhci_hcd *xhci, unsigned long delay)
{
        return mod_delayed_work(system_wq, &xhci->cmd_timer, delay);
}

static struct xhci_command *xhci_next_queued_cmd(struct xhci_hcd *xhci)
{
        return list_first_entry_or_null(&xhci->cmd_list, struct xhci_command,
                                        cmd_list);
}

/*
 * Turn all commands on command ring with status set to "aborted" to no-op trbs.
 * If there are other commands waiting then restart the ring and kick the timer.
 * This must be called with command ring stopped and xhci->lock held.
 */
static void xhci_handle_stopped_cmd_ring(struct xhci_hcd *xhci,
                                         struct xhci_command *cur_cmd)
{
        struct xhci_command *i_cmd;

        /* Turn all aborted commands in list to no-ops, then restart */
        list_for_each_entry(i_cmd, &xhci->cmd_list, cmd_list) {

                if (i_cmd->status != COMP_COMMAND_ABORTED)
                        continue;

                i_cmd->status = COMP_COMMAND_RING_STOPPED;

                xhci_dbg(xhci, "Turn aborted command %p to no-op\n",
                         i_cmd->command_trb);

                trb_to_noop(i_cmd->command_trb, TRB_CMD_NOOP);

                /*
                 * caller waiting for completion is called when command
                 *  completion event is received for these no-op commands
                 */
        }

        xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;

        /* ring command ring doorbell to restart the command ring */
        if ((xhci->cmd_ring->dequeue != xhci->cmd_ring->enqueue) &&
            !(xhci->xhc_state & XHCI_STATE_DYING)) {
                xhci->current_cmd = cur_cmd;
                xhci_mod_cmd_timer(xhci, XHCI_CMD_DEFAULT_TIMEOUT);
                xhci_ring_cmd_db(xhci);
        }
}

/* Must be called with xhci->lock held, releases and aquires lock back */
static int xhci_abort_cmd_ring(struct xhci_hcd *xhci, unsigned long flags)
{
        u32 temp_32;
        int ret;

        xhci_dbg(xhci, "Abort command ring\n");

        reinit_completion(&xhci->cmd_ring_stop_completion);

        /*
         * The control bits like command stop, abort are located in lower
         * dword of the command ring control register. Limit the write
         * to the lower dword to avoid corrupting the command ring pointer
         * in case if the command ring is stopped by the time upper dword
         * is written.
         */
        temp_32 = readl(&xhci->op_regs->cmd_ring);
        writel(temp_32 | CMD_RING_ABORT, &xhci->op_regs->cmd_ring);

        /* Section 4.6.1.2 of xHCI 1.0 spec says software should also time the
         * completion of the Command Abort operation. If CRR is not negated in 5
         * seconds then driver handles it as if host died (-ENODEV).
         * In the future we should distinguish between -ENODEV and -ETIMEDOUT
         * and try to recover a -ETIMEDOUT with a host controller reset.
         */
        ret = xhci_handshake(&xhci->op_regs->cmd_ring,
                        CMD_RING_RUNNING, 0, 5 * 1000 * 1000);
        if (ret < 0) {
                xhci_err(xhci, "Abort failed to stop command ring: %d\n", ret);
                xhci_halt(xhci);
                xhci_hc_died(xhci);
                return ret;
        }
        /*
         * Writing the CMD_RING_ABORT bit should cause a cmd completion event,
         * however on some host hw the CMD_RING_RUNNING bit is correctly cleared
         * but the completion event in never sent. Wait 2 secs (arbitrary
         * number) to handle those cases after negation of CMD_RING_RUNNING.
         */
        spin_unlock_irqrestore(&xhci->lock, flags);
        ret = wait_for_completion_timeout(&xhci->cmd_ring_stop_completion,
                                          msecs_to_jiffies(2000));
        spin_lock_irqsave(&xhci->lock, flags);
        if (!ret) {
                xhci_dbg(xhci, "No stop event for abort, ring start fail?\n");
                xhci_cleanup_command_queue(xhci);
        } else {
                xhci_handle_stopped_cmd_ring(xhci, xhci_next_queued_cmd(xhci));
        }
        return 0;
}

void xhci_ring_ep_doorbell(struct xhci_hcd *xhci,
                unsigned int slot_id,
                unsigned int ep_index,
                unsigned int stream_id)
{
        __le32 __iomem *db_addr = &xhci->dba->doorbell[slot_id];
        struct xhci_virt_ep *ep = &xhci->devs[slot_id]->eps[ep_index];
        unsigned int ep_state = ep->ep_state;

        /* Don't ring the doorbell for this endpoint if there are pending
         * cancellations because we don't want to interrupt processing.
         * We don't want to restart any stream rings if there's a set dequeue
         * pointer command pending because the device can choose to start any
         * stream once the endpoint is on the HW schedule.
         */
        if ((ep_state & EP_STOP_CMD_PENDING) || (ep_state & SET_DEQ_PENDING) ||
            (ep_state & EP_HALTED) || (ep_state & EP_CLEARING_TT))
                return;

        trace_xhci_ring_ep_doorbell(slot_id, DB_VALUE(ep_index, stream_id));

        writel(DB_VALUE(ep_index, stream_id), db_addr);
        /* flush the write */
        readl(db_addr);
}

/* Ring the doorbell for any rings with pending URBs */
static void ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
                unsigned int slot_id,
                unsigned int ep_index)
{
        unsigned int stream_id;
        struct xhci_virt_ep *ep;

        ep = &xhci->devs[slot_id]->eps[ep_index];

        /* A ring has pending URBs if its TD list is not empty */
        if (!(ep->ep_state & EP_HAS_STREAMS)) {
                if (ep->ring && !(list_empty(&ep->ring->td_list)))
                        xhci_ring_ep_doorbell(xhci, slot_id, ep_index, 0);
                return;
        }

        for (stream_id = 1; stream_id < ep->stream_info->num_streams;
                        stream_id++) {
                struct xhci_stream_info *stream_info = ep->stream_info;
                if (!list_empty(&stream_info->stream_rings[stream_id]->td_list))
                        xhci_ring_ep_doorbell(xhci, slot_id, ep_index,
                                                stream_id);
        }
}

void xhci_ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
                unsigned int slot_id,
                unsigned int ep_index)
{
        ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
}

static struct xhci_virt_ep *xhci_get_virt_ep(struct xhci_hcd *xhci,
                                             unsigned int slot_id,
                                             unsigned int ep_index)
{
        if (slot_id == 0 || slot_id >= MAX_HC_SLOTS) {
                xhci_warn(xhci, "Invalid slot_id %u\n", slot_id);
                return NULL;
        }
        if (ep_index >= EP_CTX_PER_DEV) {
                xhci_warn(xhci, "Invalid endpoint index %u\n", ep_index);
                return NULL;
        }
        if (!xhci->devs[slot_id]) {
                xhci_warn(xhci, "No xhci virt device for slot_id %u\n", slot_id);
                return NULL;
        }

        return &xhci->devs[slot_id]->eps[ep_index];
}

static struct xhci_ring *xhci_virt_ep_to_ring(struct xhci_hcd *xhci,
                                              struct xhci_virt_ep *ep,
                                              unsigned int stream_id)
{
        /* common case, no streams */
        if (!(ep->ep_state & EP_HAS_STREAMS))
                return ep->ring;

        if (!ep->stream_info)
                return NULL;

        if (stream_id == 0 || stream_id >= ep->stream_info->num_streams) {
                xhci_warn(xhci, "Invalid stream_id %u request for slot_id %u ep_index %u\n",
                          stream_id, ep->vdev->slot_id, ep->ep_index);
                return NULL;
        }

        return ep->stream_info->stream_rings[stream_id];
}

/* Get the right ring for the given slot_id, ep_index and stream_id.
 * If the endpoint supports streams, boundary check the URB's stream ID.
 * If the endpoint doesn't support streams, return the singular endpoint ring.
 */
struct xhci_ring *xhci_triad_to_transfer_ring(struct xhci_hcd *xhci,
                unsigned int slot_id, unsigned int ep_index,
                unsigned int stream_id)
{
        struct xhci_virt_ep *ep;

        ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
        if (!ep)
                return NULL;

        return xhci_virt_ep_to_ring(xhci, ep, stream_id);
}


/*
 * Get the hw dequeue pointer xHC stopped on, either directly from the
 * endpoint context, or if streams are in use from the stream context.
 * The returned hw_dequeue contains the lowest four bits with cycle state
 * and possbile stream context type.
 */
static u64 xhci_get_hw_deq(struct xhci_hcd *xhci, struct xhci_virt_device *vdev,
                           unsigned int ep_index, unsigned int stream_id)
{
        struct xhci_ep_ctx *ep_ctx;
        struct xhci_stream_ctx *st_ctx;
        struct xhci_virt_ep *ep;

        ep = &vdev->eps[ep_index];

        if (ep->ep_state & EP_HAS_STREAMS) {
                st_ctx = &ep->stream_info->stream_ctx_array[stream_id];
                return le64_to_cpu(st_ctx->stream_ring);
        }
        ep_ctx = xhci_get_ep_ctx(xhci, vdev->out_ctx, ep_index);
        return le64_to_cpu(ep_ctx->deq);
}

static int xhci_move_dequeue_past_td(struct xhci_hcd *xhci,
                                unsigned int slot_id, unsigned int ep_index,
                                unsigned int stream_id, struct xhci_td *td)
{
        struct xhci_virt_device *dev = xhci->devs[slot_id];
        struct xhci_virt_ep *ep = &dev->eps[ep_index];
        struct xhci_ring *ep_ring;
        struct xhci_command *cmd;
        struct xhci_segment *new_seg;
        struct xhci_segment *halted_seg = NULL;
        union xhci_trb *new_deq;
        int new_cycle;
        union xhci_trb *halted_trb;
        int index = 0;
        dma_addr_t addr;
        u64 hw_dequeue;
        bool cycle_found = false;
        bool td_last_trb_found = false;
        u32 trb_sct = 0;
        int ret;

        ep_ring = xhci_triad_to_transfer_ring(xhci, slot_id,
                        ep_index, stream_id);
        if (!ep_ring) {
                xhci_warn(xhci, "WARN can't find new dequeue, invalid stream ID %u\n",
                          stream_id);
                return -ENODEV;
        }
        /*
         * A cancelled TD can complete with a stall if HW cached the trb.
         * In this case driver can't find td, but if the ring is empty we
         * can move the dequeue pointer to the current enqueue position.
         * We shouldn't hit this anymore as cached cancelled TRBs are given back
         * after clearing the cache, but be on the safe side and keep it anyway
         */
        if (!td) {
                if (list_empty(&ep_ring->td_list)) {
                        new_seg = ep_ring->enq_seg;
                        new_deq = ep_ring->enqueue;
                        new_cycle = ep_ring->cycle_state;
                        xhci_dbg(xhci, "ep ring empty, Set new dequeue = enqueue");
                        goto deq_found;
                } else {
                        xhci_warn(xhci, "Can't find new dequeue state, missing td\n");
                        return -EINVAL;
                }
        }

        hw_dequeue = xhci_get_hw_deq(xhci, dev, ep_index, stream_id);
        new_seg = ep_ring->deq_seg;
        new_deq = ep_ring->dequeue;

        /*
         * Quirk: xHC write-back of the DCS field in the hardware dequeue
         * pointer is wrong - use the cycle state of the TRB pointed to by
         * the dequeue pointer.
         */
        if (xhci->quirks & XHCI_EP_CTX_BROKEN_DCS &&
            !(ep->ep_state & EP_HAS_STREAMS))
                halted_seg = trb_in_td(xhci, td->start_seg,
                                       td->first_trb, td->last_trb,
                                       hw_dequeue & ~0xf, false);
        if (halted_seg) {
                index = ((dma_addr_t)(hw_dequeue & ~0xf) - halted_seg->dma) /
                         sizeof(*halted_trb);
                halted_trb = &halted_seg->trbs[index];
                new_cycle = halted_trb->generic.field[3] & 0x1;
                xhci_dbg(xhci, "Endpoint DCS = %d TRB index = %d cycle = %d\n",
                         (u8)(hw_dequeue & 0x1), index, new_cycle);
        } else {
                new_cycle = hw_dequeue & 0x1;
        }

        /*
         * We want to find the pointer, segment and cycle state of the new trb
         * (the one after current TD's last_trb). We know the cycle state at
         * hw_dequeue, so walk the ring until both hw_dequeue and last_trb are
         * found.
         */
        do {
                if (!cycle_found && xhci_trb_virt_to_dma(new_seg, new_deq)
                    == (dma_addr_t)(hw_dequeue & ~0xf)) {
                        cycle_found = true;
                        if (td_last_trb_found)
                                break;
                }
                if (new_deq == td->last_trb)
                        td_last_trb_found = true;

                if (cycle_found && trb_is_link(new_deq) &&
                    link_trb_toggles_cycle(new_deq))
                        new_cycle ^= 0x1;

                next_trb(xhci, ep_ring, &new_seg, &new_deq);

                /* Search wrapped around, bail out */
                if (new_deq == ep->ring->dequeue) {
                        xhci_err(xhci, "Error: Failed finding new dequeue state\n");
                        return -EINVAL;
                }

        } while (!cycle_found || !td_last_trb_found);

deq_found:

        /* Don't update the ring cycle state for the producer (us). */
        addr = xhci_trb_virt_to_dma(new_seg, new_deq);
        if (addr == 0) {
                xhci_warn(xhci, "Can't find dma of new dequeue ptr\n");
                xhci_warn(xhci, "deq seg = %p, deq ptr = %p\n", new_seg, new_deq);
                return -EINVAL;
        }

        if ((ep->ep_state & SET_DEQ_PENDING)) {
                xhci_warn(xhci, "Set TR Deq already pending, don't submit for 0x%pad\n",
                          &addr);
                return -EBUSY;
        }

        /* This function gets called from contexts where it cannot sleep */
        cmd = xhci_alloc_command(xhci, false, GFP_ATOMIC);
        if (!cmd) {
                xhci_warn(xhci, "Can't alloc Set TR Deq cmd 0x%pad\n", &addr);
                return -ENOMEM;
        }

        if (stream_id)
                trb_sct = SCT_FOR_TRB(SCT_PRI_TR);
        ret = queue_command(xhci, cmd,
                lower_32_bits(addr) | trb_sct | new_cycle,
                upper_32_bits(addr),
                STREAM_ID_FOR_TRB(stream_id), SLOT_ID_FOR_TRB(slot_id) |
                EP_ID_FOR_TRB(ep_index) | TRB_TYPE(TRB_SET_DEQ), false);
        if (ret < 0) {
                xhci_free_command(xhci, cmd);
                return ret;
        }
        ep->queued_deq_seg = new_seg;
        ep->queued_deq_ptr = new_deq;

        xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                       "Set TR Deq ptr 0x%llx, cycle %u\n", addr, new_cycle);

        /* Stop the TD queueing code from ringing the doorbell until
         * this command completes.  The HC won't set the dequeue pointer
         * if the ring is running, and ringing the doorbell starts the
         * ring running.
         */
        ep->ep_state |= SET_DEQ_PENDING;
        xhci_ring_cmd_db(xhci);
        return 0;
}

/* flip_cycle means flip the cycle bit of all but the first and last TRB.
 * (The last TRB actually points to the ring enqueue pointer, which is not part
 * of this TD.)  This is used to remove partially enqueued isoc TDs from a ring.
 */
static void td_to_noop(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
                       struct xhci_td *td, bool flip_cycle)
{
        struct xhci_segment *seg        = td->start_seg;
        union xhci_trb *trb             = td->first_trb;

        while (1) {
                trb_to_noop(trb, TRB_TR_NOOP);

                /* flip cycle if asked to */
                if (flip_cycle && trb != td->first_trb && trb != td->last_trb)
                        trb->generic.field[3] ^= cpu_to_le32(TRB_CYCLE);

                if (trb == td->last_trb)
                        break;

                next_trb(xhci, ep_ring, &seg, &trb);
        }
}

static void xhci_stop_watchdog_timer_in_irq(struct xhci_hcd *xhci,
                struct xhci_virt_ep *ep)
{
        ep->ep_state &= ~EP_STOP_CMD_PENDING;
        /* Can't del_timer_sync in interrupt */
        del_timer(&ep->stop_cmd_timer);
}

/*
 * Must be called with xhci->lock held in interrupt context,
 * releases and re-acquires xhci->lock
 */
static void xhci_giveback_urb_in_irq(struct xhci_hcd *xhci,
                                     struct xhci_td *cur_td, int status)
{
        struct urb      *urb            = cur_td->urb;
        struct urb_priv *urb_priv       = urb->hcpriv;
        struct usb_hcd  *hcd            = bus_to_hcd(urb->dev->bus);

        if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
                xhci_to_hcd(xhci)->self.bandwidth_isoc_reqs--;
                if (xhci_to_hcd(xhci)->self.bandwidth_isoc_reqs == 0) {
                        if (xhci->quirks & XHCI_AMD_PLL_FIX)
                                usb_amd_quirk_pll_enable();
                }
        }
        xhci_urb_free_priv(urb_priv);
        usb_hcd_unlink_urb_from_ep(hcd, urb);
        trace_xhci_urb_giveback(urb);
        usb_hcd_giveback_urb(hcd, urb, status);
}

static void xhci_unmap_td_bounce_buffer(struct xhci_hcd *xhci,
                struct xhci_ring *ring, struct xhci_td *td)
{
        struct device *dev = xhci_to_hcd(xhci)->self.controller;
        struct xhci_segment *seg = td->bounce_seg;
        struct urb *urb = td->urb;
        size_t len;

        if (!ring || !seg || !urb)
                return;

        if (usb_urb_dir_out(urb)) {
                dma_unmap_single(dev, seg->bounce_dma, ring->bounce_buf_len,
                                 DMA_TO_DEVICE);
                return;
        }

        dma_unmap_single(dev, seg->bounce_dma, ring->bounce_buf_len,
                         DMA_FROM_DEVICE);
        /* for in tranfers we need to copy the data from bounce to sg */
        if (urb->num_sgs) {
                len = sg_pcopy_from_buffer(urb->sg, urb->num_sgs, seg->bounce_buf,
                                           seg->bounce_len, seg->bounce_offs);
                if (len != seg->bounce_len)
                        xhci_warn(xhci, "WARN Wrong bounce buffer read length: %zu != %d\n",
                                  len, seg->bounce_len);
        } else {
                memcpy(urb->transfer_buffer + seg->bounce_offs, seg->bounce_buf,
                       seg->bounce_len);
        }
        seg->bounce_len = 0;
        seg->bounce_offs = 0;
}

static int xhci_td_cleanup(struct xhci_hcd *xhci, struct xhci_td *td,
                           struct xhci_ring *ep_ring, int status)
{
        struct urb *urb = NULL;

        /* Clean up the endpoint's TD list */
        urb = td->urb;

        /* if a bounce buffer was used to align this td then unmap it */
        xhci_unmap_td_bounce_buffer(xhci, ep_ring, td);

        /* Do one last check of the actual transfer length.
         * If the host controller said we transferred more data than the buffer
         * length, urb->actual_length will be a very big number (since it's
         * unsigned).  Play it safe and say we didn't transfer anything.
         */
        if (urb->actual_length > urb->transfer_buffer_length) {
                xhci_warn(xhci, "URB req %u and actual %u transfer length mismatch\n",
                          urb->transfer_buffer_length, urb->actual_length);
                urb->actual_length = 0;
                status = 0;
        }
        /* TD might be removed from td_list if we are giving back a cancelled URB */
        if (!list_empty(&td->td_list))
                list_del_init(&td->td_list);
        /* Giving back a cancelled URB, or if a slated TD completed anyway */
        if (!list_empty(&td->cancelled_td_list))
                list_del_init(&td->cancelled_td_list);

        inc_td_cnt(urb);
        /* Giveback the urb when all the tds are completed */
        if (last_td_in_urb(td)) {
                if ((urb->actual_length != urb->transfer_buffer_length &&
                     (urb->transfer_flags & URB_SHORT_NOT_OK)) ||
                    (status != 0 && !usb_endpoint_xfer_isoc(&urb->ep->desc)))
                        xhci_dbg(xhci, "Giveback URB %p, len = %d, expected = %d, status = %d\n",
                                 urb, urb->actual_length,
                                 urb->transfer_buffer_length, status);

                /* set isoc urb status to 0 just as EHCI, UHCI, and OHCI */
                if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS)
                        status = 0;
                xhci_giveback_urb_in_irq(xhci, td, status);
        }

        return 0;
}


/* Complete the cancelled URBs we unlinked from td_list. */
static void xhci_giveback_invalidated_tds(struct xhci_virt_ep *ep)
{
        struct xhci_ring *ring;
        struct xhci_td *td, *tmp_td;

        list_for_each_entry_safe(td, tmp_td, &ep->cancelled_td_list,
                                 cancelled_td_list) {

                ring = xhci_urb_to_transfer_ring(ep->xhci, td->urb);

                if (td->cancel_status == TD_CLEARED) {
                        xhci_dbg(ep->xhci, "%s: Giveback cancelled URB %p TD\n",
                                 __func__, td->urb);
                        xhci_td_cleanup(ep->xhci, td, ring, td->status);
                } else {
                        xhci_dbg(ep->xhci, "%s: Keep cancelled URB %p TD as cancel_status is %d\n",
                                 __func__, td->urb, td->cancel_status);
                }
                if (ep->xhci->xhc_state & XHCI_STATE_DYING)
                        return;
        }
}

static int xhci_reset_halted_ep(struct xhci_hcd *xhci, unsigned int slot_id,
                                unsigned int ep_index, enum xhci_ep_reset_type reset_type)
{
        struct xhci_command *command;
        int ret = 0;

        command = xhci_alloc_command(xhci, false, GFP_ATOMIC);
        if (!command) {
                ret = -ENOMEM;
                goto done;
        }

        xhci_dbg(xhci, "%s-reset ep %u, slot %u\n",
                 (reset_type == EP_HARD_RESET) ? "Hard" : "Soft",
                 ep_index, slot_id);

        ret = xhci_queue_reset_ep(xhci, command, slot_id, ep_index, reset_type);
done:
        if (ret)
                xhci_err(xhci, "ERROR queuing reset endpoint for slot %d ep_index %d, %d\n",
                         slot_id, ep_index, ret);
        return ret;
}

static int xhci_handle_halted_endpoint(struct xhci_hcd *xhci,
                                struct xhci_virt_ep *ep, unsigned int stream_id,
                                struct xhci_td *td,
                                enum xhci_ep_reset_type reset_type)
{
        unsigned int slot_id = ep->vdev->slot_id;
        int err;

        /*
         * Avoid resetting endpoint if link is inactive. Can cause host hang.
         * Device will be reset soon to recover the link so don't do anything
         */
        if (ep->vdev->flags & VDEV_PORT_ERROR)
                return -ENODEV;

        /* add td to cancelled list and let reset ep handler take care of it */
        if (reset_type == EP_HARD_RESET) {
                ep->ep_state |= EP_HARD_CLEAR_TOGGLE;
                if (td && list_empty(&td->cancelled_td_list)) {
                        list_add_tail(&td->cancelled_td_list, &ep->cancelled_td_list);
                        td->cancel_status = TD_HALTED;
                }
        }

        if (ep->ep_state & EP_HALTED) {
                xhci_dbg(xhci, "Reset ep command for ep_index %d already pending\n",
                         ep->ep_index);
                return 0;
        }

        err = xhci_reset_halted_ep(xhci, slot_id, ep->ep_index, reset_type);
        if (err)
                return err;

        ep->ep_state |= EP_HALTED;

        xhci_ring_cmd_db(xhci);

        return 0;
}

/*
 * Fix up the ep ring first, so HW stops executing cancelled TDs.
 * We have the xHCI lock, so nothing can modify this list until we drop it.
 * We're also in the event handler, so we can't get re-interrupted if another
 * Stop Endpoint command completes.
 *
 * only call this when ring is not in a running state
 */

static int xhci_invalidate_cancelled_tds(struct xhci_virt_ep *ep)
{
        struct xhci_hcd         *xhci;
        struct xhci_td          *td = NULL;
        struct xhci_td          *tmp_td = NULL;
        struct xhci_td          *cached_td = NULL;
        struct xhci_ring        *ring;
        u64                     hw_deq;
        unsigned int            slot_id = ep->vdev->slot_id;
        int                     err;

        xhci = ep->xhci;

        list_for_each_entry_safe(td, tmp_td, &ep->cancelled_td_list, cancelled_td_list) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                               "Removing canceled TD starting at 0x%llx (dma) in stream %u URB %p",
                               (unsigned long long)xhci_trb_virt_to_dma(
                                       td->start_seg, td->first_trb),
                               td->urb->stream_id, td->urb);
                list_del_init(&td->td_list);
                ring = xhci_urb_to_transfer_ring(xhci, td->urb);
                if (!ring) {
                        xhci_warn(xhci, "WARN Cancelled URB %p has invalid stream ID %u.\n",
                                  td->urb, td->urb->stream_id);
                        continue;
                }
                /*
                 * If a ring stopped on the TD we need to cancel then we have to
                 * move the xHC endpoint ring dequeue pointer past this TD.
                 * Rings halted due to STALL may show hw_deq is past the stalled
                 * TD, but still require a set TR Deq command to flush xHC cache.
                 */
                hw_deq = xhci_get_hw_deq(xhci, ep->vdev, ep->ep_index,
                                         td->urb->stream_id);
                hw_deq &= ~0xf;

                if (td->cancel_status == TD_HALTED ||
                    trb_in_td(xhci, td->start_seg, td->first_trb, td->last_trb, hw_deq, false)) {
                        switch (td->cancel_status) {
                        case TD_CLEARED: /* TD is already no-op */
                        case TD_CLEARING_CACHE: /* set TR deq command already queued */
                                break;
                        case TD_DIRTY: /* TD is cached, clear it */
                        case TD_HALTED:
                                td->cancel_status = TD_CLEARING_CACHE;
                                if (cached_td)
                                        /* FIXME  stream case, several stopped rings */
                                        xhci_dbg(xhci,
                                                 "Move dq past stream %u URB %p instead of stream %u URB %p\n",
                                                 td->urb->stream_id, td->urb,
                                                 cached_td->urb->stream_id, cached_td->urb);
                                cached_td = td;

                                break;
                        }
                } else {
                        td_to_noop(xhci, ring, td, false);
                        td->cancel_status = TD_CLEARED;
                }
        }

        /* If there's no need to move the dequeue pointer then we're done */
        if (!cached_td)
                return 0;

        err = xhci_move_dequeue_past_td(xhci, slot_id, ep->ep_index,
                                        cached_td->urb->stream_id,
                                        cached_td);
        if (err) {
                /* Failed to move past cached td, just set cached TDs to no-op */
                list_for_each_entry_safe(td, tmp_td, &ep->cancelled_td_list, cancelled_td_list) {
                        if (td->cancel_status != TD_CLEARING_CACHE)
                                continue;
                        xhci_dbg(xhci, "Failed to clear cancelled cached URB %p, mark clear anyway\n",
                                 td->urb);
                        td_to_noop(xhci, ring, td, false);
                        td->cancel_status = TD_CLEARED;
                }
        }
        return 0;
}

/*
 * Returns the TD the endpoint ring halted on.
 * Only call for non-running rings without streams.
 */
static struct xhci_td *find_halted_td(struct xhci_virt_ep *ep)
{
        struct xhci_td  *td;
        u64             hw_deq;

        if (!list_empty(&ep->ring->td_list)) { /* Not streams compatible */
                hw_deq = xhci_get_hw_deq(ep->xhci, ep->vdev, ep->ep_index, 0);
                hw_deq &= ~0xf;
                td = list_first_entry(&ep->ring->td_list, struct xhci_td, td_list);
                if (trb_in_td(ep->xhci, td->start_seg, td->first_trb,
                                td->last_trb, hw_deq, false))
                        return td;
        }
        return NULL;
}

/*
 * When we get a command completion for a Stop Endpoint Command, we need to
 * unlink any cancelled TDs from the ring.  There are two ways to do that:
 *
 *  1. If the HW was in the middle of processing the TD that needs to be
 *     cancelled, then we must move the ring's dequeue pointer past the last TRB
 *     in the TD with a Set Dequeue Pointer Command.
 *  2. Otherwise, we turn all the TRBs in the TD into No-op TRBs (with the chain
 *     bit cleared) so that the HW will skip over them.
 */
static void xhci_handle_cmd_stop_ep(struct xhci_hcd *xhci, int slot_id,
                                    union xhci_trb *trb, u32 comp_code)
{
        unsigned int ep_index;
        struct xhci_virt_ep *ep;
        struct xhci_ep_ctx *ep_ctx;
        struct xhci_td *td = NULL;
        enum xhci_ep_reset_type reset_type;
        struct xhci_command *command;
        int err;

        if (unlikely(TRB_TO_SUSPEND_PORT(le32_to_cpu(trb->generic.field[3])))) {
                if (!xhci->devs[slot_id])
                        xhci_warn(xhci, "Stop endpoint command completion for disabled slot %u\n",
                                  slot_id);
                return;
        }

        ep_index = TRB_TO_EP_INDEX(le32_to_cpu(trb->generic.field[3]));
        ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
        if (!ep)
                return;

        ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep_index);

        trace_xhci_handle_cmd_stop_ep(ep_ctx);

        if (comp_code == COMP_CONTEXT_STATE_ERROR) {
        /*
         * If stop endpoint command raced with a halting endpoint we need to
         * reset the host side endpoint first.
         * If the TD we halted on isn't cancelled the TD should be given back
         * with a proper error code, and the ring dequeue moved past the TD.
         * If streams case we can't find hw_deq, or the TD we halted on so do a
         * soft reset.
         *
         * Proper error code is unknown here, it would be -EPIPE if device side
         * of enadpoit halted (aka STALL), and -EPROTO if not (transaction error)
         * We use -EPROTO, if device is stalled it should return a stall error on
         * next transfer, which then will return -EPIPE, and device side stall is
         * noted and cleared by class driver.
         */
                switch (GET_EP_CTX_STATE(ep_ctx)) {
                case EP_STATE_HALTED:
                        xhci_dbg(xhci, "Stop ep completion raced with stall, reset ep\n");
                        if (ep->ep_state & EP_HAS_STREAMS) {
                                reset_type = EP_SOFT_RESET;
                        } else {
                                reset_type = EP_HARD_RESET;
                                td = find_halted_td(ep);
                                if (td)
                                        td->status = -EPROTO;
                        }
                        /* reset ep, reset handler cleans up cancelled tds */
                        err = xhci_handle_halted_endpoint(xhci, ep, 0, td,
                                                          reset_type);
                        if (err)
                                break;
                        xhci_stop_watchdog_timer_in_irq(xhci, ep);
                        return;
                case EP_STATE_RUNNING:
                        /* Race, HW handled stop ep cmd before ep was running */
                        xhci_dbg(xhci, "Stop ep completion ctx error, ep is running\n");

                        command = xhci_alloc_command(xhci, false, GFP_ATOMIC);
                        if (!command)
                                xhci_stop_watchdog_timer_in_irq(xhci, ep);

                        mod_timer(&ep->stop_cmd_timer,
                                  jiffies + XHCI_STOP_EP_CMD_TIMEOUT * HZ);
                        xhci_queue_stop_endpoint(xhci, command, slot_id, ep_index, 0);
                        xhci_ring_cmd_db(xhci);

                        return;
                default:
                        break;
                }
        }
        /* will queue a set TR deq if stopped on a cancelled, uncleared TD */
        xhci_invalidate_cancelled_tds(ep);
        xhci_stop_watchdog_timer_in_irq(xhci, ep);

        /* Otherwise ring the doorbell(s) to restart queued transfers */
        xhci_giveback_invalidated_tds(ep);
        ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
}

static void xhci_kill_ring_urbs(struct xhci_hcd *xhci, struct xhci_ring *ring)
{
        struct xhci_td *cur_td;
        struct xhci_td *tmp;

        list_for_each_entry_safe(cur_td, tmp, &ring->td_list, td_list) {
                list_del_init(&cur_td->td_list);

                if (!list_empty(&cur_td->cancelled_td_list))
                        list_del_init(&cur_td->cancelled_td_list);

                xhci_unmap_td_bounce_buffer(xhci, ring, cur_td);

                inc_td_cnt(cur_td->urb);
                if (last_td_in_urb(cur_td))
                        xhci_giveback_urb_in_irq(xhci, cur_td, -ESHUTDOWN);
        }
}

static void xhci_kill_endpoint_urbs(struct xhci_hcd *xhci,
                int slot_id, int ep_index)
{
        struct xhci_td *cur_td;
        struct xhci_td *tmp;
        struct xhci_virt_ep *ep;
        struct xhci_ring *ring;

        ep = &xhci->devs[slot_id]->eps[ep_index];
        if ((ep->ep_state & EP_HAS_STREAMS) ||
                        (ep->ep_state & EP_GETTING_NO_STREAMS)) {
                int stream_id;

                for (stream_id = 1; stream_id < ep->stream_info->num_streams;
                                stream_id++) {
                        ring = ep->stream_info->stream_rings[stream_id];
                        if (!ring)
                                continue;

                        xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                                        "Killing URBs for slot ID %u, ep index %u, stream %u",
                                        slot_id, ep_index, stream_id);
                        xhci_kill_ring_urbs(xhci, ring);
                }
        } else {
                ring = ep->ring;
                if (!ring)
                        return;
                xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                                "Killing URBs for slot ID %u, ep index %u",
                                slot_id, ep_index);
                xhci_kill_ring_urbs(xhci, ring);
        }

        list_for_each_entry_safe(cur_td, tmp, &ep->cancelled_td_list,
                        cancelled_td_list) {
                list_del_init(&cur_td->cancelled_td_list);
                inc_td_cnt(cur_td->urb);

                if (last_td_in_urb(cur_td))
                        xhci_giveback_urb_in_irq(xhci, cur_td, -ESHUTDOWN);
        }
}

/*
 * host controller died, register read returns 0xffffffff
 * Complete pending commands, mark them ABORTED.
 * URBs need to be given back as usb core might be waiting with device locks
 * held for the URBs to finish during device disconnect, blocking host remove.
 *
 * Call with xhci->lock held.
 * lock is relased and re-acquired while giving back urb.
 */
void xhci_hc_died(struct xhci_hcd *xhci)
{
        int i, j;

        if (xhci->xhc_state & XHCI_STATE_DYING)
                return;

        xhci_err(xhci, "xHCI host controller not responding, assume dead\n");
        xhci->xhc_state |= XHCI_STATE_DYING;

        xhci_cleanup_command_queue(xhci);

        /* return any pending urbs, remove may be waiting for them */
        for (i = 0; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
                if (!xhci->devs[i])
                        continue;
                for (j = 0; j < 31; j++)
                        xhci_kill_endpoint_urbs(xhci, i, j);
        }

        /* inform usb core hc died if PCI remove isn't already handling it */
        if (!(xhci->xhc_state & XHCI_STATE_REMOVING))
                usb_hc_died(xhci_to_hcd(xhci));
}

/* Watchdog timer function for when a stop endpoint command fails to complete.
 * In this case, we assume the host controller is broken or dying or dead.  The
 * host may still be completing some other events, so we have to be careful to
 * let the event ring handler and the URB dequeueing/enqueueing functions know
 * through xhci->state.
 *
 * The timer may also fire if the host takes a very long time to respond to the
 * command, and the stop endpoint command completion handler cannot delete the
 * timer before the timer function is called.  Another endpoint cancellation may
 * sneak in before the timer function can grab the lock, and that may queue
 * another stop endpoint command and add the timer back.  So we cannot use a
 * simple flag to say whether there is a pending stop endpoint command for a
 * particular endpoint.
 *
 * Instead we use a combination of that flag and checking if a new timer is
 * pending.
 */
void xhci_stop_endpoint_command_watchdog(struct timer_list *t)
{
        struct xhci_virt_ep *ep = from_timer(ep, t, stop_cmd_timer);
        struct xhci_hcd *xhci = ep->xhci;
        unsigned long flags;
        u32 usbsts;
        char str[XHCI_MSG_MAX];

        spin_lock_irqsave(&xhci->lock, flags);

        /* bail out if cmd completed but raced with stop ep watchdog timer.*/
        if (!(ep->ep_state & EP_STOP_CMD_PENDING) ||
            timer_pending(&ep->stop_cmd_timer)) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                xhci_dbg(xhci, "Stop EP timer raced with cmd completion, exit");
                return;
        }
        usbsts = readl(&xhci->op_regs->status);

        xhci_warn(xhci, "xHCI host not responding to stop endpoint command.\n");
        xhci_warn(xhci, "USBSTS:%s\n", xhci_decode_usbsts(str, usbsts));

        ep->ep_state &= ~EP_STOP_CMD_PENDING;

        xhci_halt(xhci);

        /*
         * handle a stop endpoint cmd timeout as if host died (-ENODEV).
         * In the future we could distinguish between -ENODEV and -ETIMEDOUT
         * and try to recover a -ETIMEDOUT with a host controller reset
         */
        xhci_hc_died(xhci);

        spin_unlock_irqrestore(&xhci->lock, flags);
        xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                        "xHCI host controller is dead.");
}

static void update_ring_for_set_deq_completion(struct xhci_hcd *xhci,
                struct xhci_virt_device *dev,
                struct xhci_ring *ep_ring,
                unsigned int ep_index)
{
        union xhci_trb *dequeue_temp;
        int num_trbs_free_temp;
        bool revert = false;

        num_trbs_free_temp = ep_ring->num_trbs_free;
        dequeue_temp = ep_ring->dequeue;

        /* If we get two back-to-back stalls, and the first stalled transfer
         * ends just before a link TRB, the dequeue pointer will be left on
         * the link TRB by the code in the while loop.  So we have to update
         * the dequeue pointer one segment further, or we'll jump off
         * the segment into la-la-land.
         */
        if (trb_is_link(ep_ring->dequeue)) {
                ep_ring->deq_seg = ep_ring->deq_seg->next;
                ep_ring->dequeue = ep_ring->deq_seg->trbs;
        }

        while (ep_ring->dequeue != dev->eps[ep_index].queued_deq_ptr) {
                /* We have more usable TRBs */
                ep_ring->num_trbs_free++;
                ep_ring->dequeue++;
                if (trb_is_link(ep_ring->dequeue)) {
                        if (ep_ring->dequeue ==
                                        dev->eps[ep_index].queued_deq_ptr)
                                break;
                        ep_ring->deq_seg = ep_ring->deq_seg->next;
                        ep_ring->dequeue = ep_ring->deq_seg->trbs;
                }
                if (ep_ring->dequeue == dequeue_temp) {
                        revert = true;
                        break;
                }
        }

        if (revert) {
                xhci_dbg(xhci, "Unable to find new dequeue pointer\n");
                ep_ring->num_trbs_free = num_trbs_free_temp;
        }
}

/*
 * When we get a completion for a Set Transfer Ring Dequeue Pointer command,
 * we need to clear the set deq pending flag in the endpoint ring state, so that
 * the TD queueing code can ring the doorbell again.  We also need to ring the
 * endpoint doorbell to restart the ring, but only if there aren't more
 * cancellations pending.
 */
static void xhci_handle_cmd_set_deq(struct xhci_hcd *xhci, int slot_id,
                union xhci_trb *trb, u32 cmd_comp_code)
{
        unsigned int ep_index;
        unsigned int stream_id;
        struct xhci_ring *ep_ring;
        struct xhci_virt_ep *ep;
        struct xhci_ep_ctx *ep_ctx;
        struct xhci_slot_ctx *slot_ctx;
        struct xhci_td *td, *tmp_td;

        ep_index = TRB_TO_EP_INDEX(le32_to_cpu(trb->generic.field[3]));
        stream_id = TRB_TO_STREAM_ID(le32_to_cpu(trb->generic.field[2]));
        ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
        if (!ep)
                return;

        ep_ring = xhci_virt_ep_to_ring(xhci, ep, stream_id);
        if (!ep_ring) {
                xhci_warn(xhci, "WARN Set TR deq ptr command for freed stream ID %u\n",
                                stream_id);
                /* XXX: Harmless??? */
                goto cleanup;
        }

        ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep_index);
        slot_ctx = xhci_get_slot_ctx(xhci, ep->vdev->out_ctx);
        trace_xhci_handle_cmd_set_deq(slot_ctx);
        trace_xhci_handle_cmd_set_deq_ep(ep_ctx);

        if (cmd_comp_code != COMP_SUCCESS) {
                unsigned int ep_state;
                unsigned int slot_state;

                switch (cmd_comp_code) {
                case COMP_TRB_ERROR:
                        xhci_warn(xhci, "WARN Set TR Deq Ptr cmd invalid because of stream ID configuration\n");
                        break;
                case COMP_CONTEXT_STATE_ERROR:
                        xhci_warn(xhci, "WARN Set TR Deq Ptr cmd failed due to incorrect slot or ep state.\n");
                        ep_state = GET_EP_CTX_STATE(ep_ctx);
                        slot_state = le32_to_cpu(slot_ctx->dev_state);
                        slot_state = GET_SLOT_STATE(slot_state);
                        xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                                        "Slot state = %u, EP state = %u",
                                        slot_state, ep_state);
                        break;
                case COMP_SLOT_NOT_ENABLED_ERROR:
                        xhci_warn(xhci, "WARN Set TR Deq Ptr cmd failed because slot %u was not enabled.\n",
                                        slot_id);
                        break;
                default:
                        xhci_warn(xhci, "WARN Set TR Deq Ptr cmd with unknown completion code of %u.\n",
                                        cmd_comp_code);
                        break;
                }
                /* OK what do we do now?  The endpoint state is hosed, and we
                 * should never get to this point if the synchronization between
                 * queueing, and endpoint state are correct.  This might happen
                 * if the device gets disconnected after we've finished
                 * cancelling URBs, which might not be an error...
                 */
        } else {
                u64 deq;
                /* 4.6.10 deq ptr is written to the stream ctx for streams */
                if (ep->ep_state & EP_HAS_STREAMS) {
                        struct xhci_stream_ctx *ctx =
                                &ep->stream_info->stream_ctx_array[stream_id];
                        deq = le64_to_cpu(ctx->stream_ring) & SCTX_DEQ_MASK;
                } else {
                        deq = le64_to_cpu(ep_ctx->deq) & ~EP_CTX_CYCLE_MASK;
                }
                xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                        "Successful Set TR Deq Ptr cmd, deq = @%08llx", deq);
                if (xhci_trb_virt_to_dma(ep->queued_deq_seg,
                                         ep->queued_deq_ptr) == deq) {
                        /* Update the ring's dequeue segment and dequeue pointer
                         * to reflect the new position.
                         */
                        update_ring_for_set_deq_completion(xhci, ep->vdev,
                                ep_ring, ep_index);
                } else {
                        xhci_warn(xhci, "Mismatch between completed Set TR Deq Ptr command & xHCI internal state.\n");
                        xhci_warn(xhci, "ep deq seg = %p, deq ptr = %p\n",
                                  ep->queued_deq_seg, ep->queued_deq_ptr);
                }
        }
        /* HW cached TDs cleared from cache, give them back */
        list_for_each_entry_safe(td, tmp_td, &ep->cancelled_td_list,
                                 cancelled_td_list) {
                ep_ring = xhci_urb_to_transfer_ring(ep->xhci, td->urb);
                if (td->cancel_status == TD_CLEARING_CACHE) {
                        td->cancel_status = TD_CLEARED;
                        xhci_dbg(ep->xhci, "%s: Giveback cancelled URB %p TD\n",
                                 __func__, td->urb);
                        xhci_td_cleanup(ep->xhci, td, ep_ring, td->status);
                } else {
                        xhci_dbg(ep->xhci, "%s: Keep cancelled URB %p TD as cancel_status is %d\n",
                                 __func__, td->urb, td->cancel_status);
                }
        }
cleanup:
        ep->ep_state &= ~SET_DEQ_PENDING;
        ep->queued_deq_seg = NULL;
        ep->queued_deq_ptr = NULL;
        /* Restart any rings with pending URBs */
        ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
}

static void xhci_handle_cmd_reset_ep(struct xhci_hcd *xhci, int slot_id,
                union xhci_trb *trb, u32 cmd_comp_code)
{
        struct xhci_virt_ep *ep;
        struct xhci_ep_ctx *ep_ctx;
        unsigned int ep_index;

        ep_index = TRB_TO_EP_INDEX(le32_to_cpu(trb->generic.field[3]));
        ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
        if (!ep)
                return;

        ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep_index);
        trace_xhci_handle_cmd_reset_ep(ep_ctx);

        /* This command will only fail if the endpoint wasn't halted,
         * but we don't care.
         */
        xhci_dbg_trace(xhci, trace_xhci_dbg_reset_ep,
                "Ignoring reset ep completion code of %u", cmd_comp_code);

        /* Cleanup cancelled TDs as ep is stopped. May queue a Set TR Deq cmd */
        xhci_invalidate_cancelled_tds(ep);

        if (xhci->quirks & XHCI_RESET_EP_QUIRK)
                xhci_dbg(xhci, "Note: Removed workaround to queue config ep for this hw");
        /* Clear our internal halted state */
        ep->ep_state &= ~EP_HALTED;

        xhci_giveback_invalidated_tds(ep);

        /* if this was a soft reset, then restart */
        if ((le32_to_cpu(trb->generic.field[3])) & TRB_TSP)
                ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
}

static void xhci_handle_cmd_enable_slot(struct xhci_hcd *xhci, int slot_id,
                struct xhci_command *command, u32 cmd_comp_code)
{
        if (cmd_comp_code == COMP_SUCCESS)
                command->slot_id = slot_id;
        else
                command->slot_id = 0;
}

static void xhci_handle_cmd_disable_slot(struct xhci_hcd *xhci, int slot_id)
{
        struct xhci_virt_device *virt_dev;
        struct xhci_slot_ctx *slot_ctx;

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

        slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->out_ctx);
        trace_xhci_handle_cmd_disable_slot(slot_ctx);

        if (xhci->quirks & XHCI_EP_LIMIT_QUIRK)
                /* Delete default control endpoint resources */
                xhci_free_device_endpoint_resources(xhci, virt_dev, true);
        xhci_free_virt_device(xhci, slot_id);
}

static void xhci_handle_cmd_config_ep(struct xhci_hcd *xhci, int slot_id,
                u32 cmd_comp_code)
{
        struct xhci_virt_device *virt_dev;
        struct xhci_input_control_ctx *ctrl_ctx;
        struct xhci_ep_ctx *ep_ctx;
        unsigned int ep_index;
        unsigned int ep_state;
        u32 add_flags, drop_flags;

        /*
         * Configure endpoint commands can come from the USB core
         * configuration or alt setting changes, or because the HW
         * needed an extra configure endpoint command after a reset
         * endpoint command or streams were being configured.
         * If the command was for a halted endpoint, the xHCI driver
         * is not waiting on the configure endpoint command.
         */
        virt_dev = xhci->devs[slot_id];
        if (!virt_dev)
                return;
        ctrl_ctx = xhci_get_input_control_ctx(virt_dev->in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "Could not get input context, bad type.\n");
                return;
        }

        add_flags = le32_to_cpu(ctrl_ctx->add_flags);
        drop_flags = le32_to_cpu(ctrl_ctx->drop_flags);
        /* Input ctx add_flags are the endpoint index plus one */
        ep_index = xhci_last_valid_endpoint(add_flags) - 1;

        ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->out_ctx, ep_index);
        trace_xhci_handle_cmd_config_ep(ep_ctx);

        /* A usb_set_interface() call directly after clearing a halted
         * condition may race on this quirky hardware.  Not worth
         * worrying about, since this is prototype hardware.  Not sure
         * if this will work for streams, but streams support was
         * untested on this prototype.
         */
        if (xhci->quirks & XHCI_RESET_EP_QUIRK &&
                        ep_index != (unsigned int) -1 &&
                        add_flags - SLOT_FLAG == drop_flags) {
                ep_state = virt_dev->eps[ep_index].ep_state;
                if (!(ep_state & EP_HALTED))
                        return;
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Completed config ep cmd - "
                                "last ep index = %d, state = %d",
                                ep_index, ep_state);
                /* Clear internal halted state and restart ring(s) */
                virt_dev->eps[ep_index].ep_state &= ~EP_HALTED;
                ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
                return;
        }
        return;
}

static void xhci_handle_cmd_addr_dev(struct xhci_hcd *xhci, int slot_id)
{
        struct xhci_virt_device *vdev;
        struct xhci_slot_ctx *slot_ctx;

        vdev = xhci->devs[slot_id];
        if (!vdev)
                return;
        slot_ctx = xhci_get_slot_ctx(xhci, vdev->out_ctx);
        trace_xhci_handle_cmd_addr_dev(slot_ctx);
}

static void xhci_handle_cmd_reset_dev(struct xhci_hcd *xhci, int slot_id)
{
        struct xhci_virt_device *vdev;
        struct xhci_slot_ctx *slot_ctx;

        vdev = xhci->devs[slot_id];
        if (!vdev) {
                xhci_warn(xhci, "Reset device command completion for disabled slot %u\n",
                          slot_id);
                return;
        }
        slot_ctx = xhci_get_slot_ctx(xhci, vdev->out_ctx);
        trace_xhci_handle_cmd_reset_dev(slot_ctx);

        xhci_dbg(xhci, "Completed reset device command.\n");
}

static void xhci_handle_cmd_nec_get_fw(struct xhci_hcd *xhci,
                struct xhci_event_cmd *event)
{
        if (!(xhci->quirks & XHCI_NEC_HOST)) {
                xhci_warn(xhci, "WARN NEC_GET_FW command on non-NEC host\n");
                return;
        }
        xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                        "NEC firmware version %2x.%02x",
                        NEC_FW_MAJOR(le32_to_cpu(event->status)),
                        NEC_FW_MINOR(le32_to_cpu(event->status)));
}

static void xhci_complete_del_and_free_cmd(struct xhci_command *cmd, u32 status)
{
        list_del(&cmd->cmd_list);

        if (cmd->completion) {
                cmd->status = status;
                complete(cmd->completion);
        } else {
                kfree(cmd);
        }
}

void xhci_cleanup_command_queue(struct xhci_hcd *xhci)
{
        struct xhci_command *cur_cmd, *tmp_cmd;
        xhci->current_cmd = NULL;
        list_for_each_entry_safe(cur_cmd, tmp_cmd, &xhci->cmd_list, cmd_list)
                xhci_complete_del_and_free_cmd(cur_cmd, COMP_COMMAND_ABORTED);
}

void xhci_handle_command_timeout(struct work_struct *work)
{
        struct xhci_hcd *xhci;
        unsigned long flags;
        u64 hw_ring_state;

        xhci = container_of(to_delayed_work(work), struct xhci_hcd, cmd_timer);

        spin_lock_irqsave(&xhci->lock, flags);

        /*
         * If timeout work is pending, or current_cmd is NULL, it means we
         * raced with command completion. Command is handled so just return.
         */
        if (!xhci->current_cmd || delayed_work_pending(&xhci->cmd_timer)) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                return;
        }
        /* mark this command to be cancelled */
        xhci->current_cmd->status = COMP_COMMAND_ABORTED;

        /* Make sure command ring is running before aborting it */
        hw_ring_state = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
        if (hw_ring_state == ~(u64)0) {
                xhci_hc_died(xhci);
                goto time_out_completed;
        }

        if ((xhci->cmd_ring_state & CMD_RING_STATE_RUNNING) &&
            (hw_ring_state & CMD_RING_RUNNING))  {
                /* Prevent new doorbell, and start command abort */
                xhci->cmd_ring_state = CMD_RING_STATE_ABORTED;
                xhci_dbg(xhci, "Command timeout\n");
                xhci_abort_cmd_ring(xhci, flags);
                goto time_out_completed;
        }

        /* host removed. Bail out */
        if (xhci->xhc_state & XHCI_STATE_REMOVING) {
                xhci_dbg(xhci, "host removed, ring start fail?\n");
                xhci_cleanup_command_queue(xhci);

                goto time_out_completed;
        }

        /* command timeout on stopped ring, ring can't be aborted */
        xhci_dbg(xhci, "Command timeout on stopped ring\n");
        xhci_handle_stopped_cmd_ring(xhci, xhci->current_cmd);

time_out_completed:
        spin_unlock_irqrestore(&xhci->lock, flags);
        return;
}

static void handle_cmd_completion(struct xhci_hcd *xhci,
                struct xhci_event_cmd *event)
{
        unsigned int slot_id = TRB_TO_SLOT_ID(le32_to_cpu(event->flags));
        u64 cmd_dma;
        dma_addr_t cmd_dequeue_dma;
        u32 cmd_comp_code;
        union xhci_trb *cmd_trb;
        struct xhci_command *cmd;
        u32 cmd_type;

        if (slot_id >= MAX_HC_SLOTS) {
                xhci_warn(xhci, "Invalid slot_id %u\n", slot_id);
                return;
        }

        cmd_dma = le64_to_cpu(event->cmd_trb);
        cmd_trb = xhci->cmd_ring->dequeue;

        trace_xhci_handle_command(xhci->cmd_ring, &cmd_trb->generic);

        cmd_dequeue_dma = xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
                        cmd_trb);
        /*
         * Check whether the completion event is for our internal kept
         * command.
         */
        if (!cmd_dequeue_dma || cmd_dma != (u64)cmd_dequeue_dma) {
                xhci_warn(xhci,
                          "ERROR mismatched command completion event\n");
                return;
        }

        cmd = list_first_entry(&xhci->cmd_list, struct xhci_command, cmd_list);

        cancel_delayed_work(&xhci->cmd_timer);

        cmd_comp_code = GET_COMP_CODE(le32_to_cpu(event->status));

        /* If CMD ring stopped we own the trbs between enqueue and dequeue */
        if (cmd_comp_code == COMP_COMMAND_RING_STOPPED) {
                complete_all(&xhci->cmd_ring_stop_completion);
                return;
        }

        if (cmd->command_trb != xhci->cmd_ring->dequeue) {
                xhci_err(xhci,
                         "Command completion event does not match command\n");
                return;
        }

        /*
         * Host aborted the command ring, check if the current command was
         * supposed to be aborted, otherwise continue normally.
         * The command ring is stopped now, but the xHC will issue a Command
         * Ring Stopped event which will cause us to restart it.
         */
        if (cmd_comp_code == COMP_COMMAND_ABORTED) {
                xhci->cmd_ring_state = CMD_RING_STATE_STOPPED;
                if (cmd->status == COMP_COMMAND_ABORTED) {
                        if (xhci->current_cmd == cmd)
                                xhci->current_cmd = NULL;
                        goto event_handled;
                }
        }

        cmd_type = TRB_FIELD_TO_TYPE(le32_to_cpu(cmd_trb->generic.field[3]));
        switch (cmd_type) {
        case TRB_ENABLE_SLOT:
                xhci_handle_cmd_enable_slot(xhci, slot_id, cmd, cmd_comp_code);
                break;
        case TRB_DISABLE_SLOT:
                xhci_handle_cmd_disable_slot(xhci, slot_id);
                break;
        case TRB_CONFIG_EP:
                if (!cmd->completion)
                        xhci_handle_cmd_config_ep(xhci, slot_id, cmd_comp_code);
                break;
        case TRB_EVAL_CONTEXT:
                break;
        case TRB_ADDR_DEV:
                xhci_handle_cmd_addr_dev(xhci, slot_id);
                break;
        case TRB_STOP_RING:
                WARN_ON(slot_id != TRB_TO_SLOT_ID(
                                le32_to_cpu(cmd_trb->generic.field[3])));
                if (!cmd->completion)
                        xhci_handle_cmd_stop_ep(xhci, slot_id, cmd_trb,
                                                cmd_comp_code);
                break;
        case TRB_SET_DEQ:
                WARN_ON(slot_id != TRB_TO_SLOT_ID(
                                le32_to_cpu(cmd_trb->generic.field[3])));
                xhci_handle_cmd_set_deq(xhci, slot_id, cmd_trb, cmd_comp_code);
                break;
        case TRB_CMD_NOOP:
                /* Is this an aborted command turned to NO-OP? */
                if (cmd->status == COMP_COMMAND_RING_STOPPED)
                        cmd_comp_code = COMP_COMMAND_RING_STOPPED;
                break;
        case TRB_RESET_EP:
                WARN_ON(slot_id != TRB_TO_SLOT_ID(
                                le32_to_cpu(cmd_trb->generic.field[3])));
                xhci_handle_cmd_reset_ep(xhci, slot_id, cmd_trb, cmd_comp_code);
                break;
        case TRB_RESET_DEV:
                /* SLOT_ID field in reset device cmd completion event TRB is 0.
                 * Use the SLOT_ID from the command TRB instead (xhci 4.6.11)
                 */
                slot_id = TRB_TO_SLOT_ID(
                                le32_to_cpu(cmd_trb->generic.field[3]));
                xhci_handle_cmd_reset_dev(xhci, slot_id);
                break;
        case TRB_NEC_GET_FW:
                xhci_handle_cmd_nec_get_fw(xhci, event);
                break;
        default:
                /* Skip over unknown commands on the event ring */
                xhci_info(xhci, "INFO unknown command type %d\n", cmd_type);
                break;
        }

        /* restart timer if this wasn't the last command */
        if (!list_is_singular(&xhci->cmd_list)) {
                xhci->current_cmd = list_first_entry(&cmd->cmd_list,
                                                struct xhci_command, cmd_list);
                xhci_mod_cmd_timer(xhci, XHCI_CMD_DEFAULT_TIMEOUT);
        } else if (xhci->current_cmd == cmd) {
                xhci->current_cmd = NULL;
        }

event_handled:
        xhci_complete_del_and_free_cmd(cmd, cmd_comp_code);

        inc_deq(xhci, xhci->cmd_ring);
}

static void handle_vendor_event(struct xhci_hcd *xhci,
                                union xhci_trb *event, u32 trb_type)
{
        xhci_dbg(xhci, "Vendor specific event TRB type = %u\n", trb_type);
        if (trb_type == TRB_NEC_CMD_COMP && (xhci->quirks & XHCI_NEC_HOST))
                handle_cmd_completion(xhci, &event->event_cmd);
}

static void handle_device_notification(struct xhci_hcd *xhci,
                union xhci_trb *event)
{
        u32 slot_id;
        struct usb_device *udev;

        slot_id = TRB_TO_SLOT_ID(le32_to_cpu(event->generic.field[3]));
        if (!xhci->devs[slot_id]) {
                xhci_warn(xhci, "Device Notification event for "
                                "unused slot %u\n", slot_id);
                return;
        }

        xhci_dbg(xhci, "Device Wake Notification event for slot ID %u\n",
                        slot_id);
        udev = xhci->devs[slot_id]->udev;
        if (udev && udev->parent)
                usb_wakeup_notification(udev->parent, udev->portnum);
}

/*
 * Quirk hanlder for errata seen on Cavium ThunderX2 processor XHCI
 * Controller.
 * As per ThunderX2errata-129 USB 2 device may come up as USB 1
 * If a connection to a USB 1 device is followed by another connection
 * to a USB 2 device.
 *
 * Reset the PHY after the USB device is disconnected if device speed
 * is less than HCD_USB3.
 * Retry the reset sequence max of 4 times checking the PLL lock status.
 *
 */
static void xhci_cavium_reset_phy_quirk(struct xhci_hcd *xhci)
{
        struct usb_hcd *hcd = xhci_to_hcd(xhci);
        u32 pll_lock_check;
        u32 retry_count = 4;

        do {
                /* Assert PHY reset */
                writel(0x6F, hcd->regs + 0x1048);
                udelay(10);
                /* De-assert the PHY reset */
                writel(0x7F, hcd->regs + 0x1048);
                udelay(200);
                pll_lock_check = readl(hcd->regs + 0x1070);
        } while (!(pll_lock_check & 0x1) && --retry_count);
}

static void handle_port_status(struct xhci_hcd *xhci,
                union xhci_trb *event)
{
        struct usb_hcd *hcd;
        u32 port_id;
        u32 portsc, cmd_reg;
        int max_ports;
        int slot_id;
        unsigned int hcd_portnum;
        struct xhci_bus_state *bus_state;
        bool bogus_port_status = false;
        struct xhci_port *port;

        /* Port status change events always have a successful completion code */
        if (GET_COMP_CODE(le32_to_cpu(event->generic.field[2])) != COMP_SUCCESS)
                xhci_warn(xhci,
                          "WARN: xHC returned failed port status event\n");

        port_id = GET_PORT_ID(le32_to_cpu(event->generic.field[0]));
        max_ports = HCS_MAX_PORTS(xhci->hcs_params1);

        if ((port_id <= 0) || (port_id > max_ports)) {
                xhci_warn(xhci, "Port change event with invalid port ID %d\n",
                          port_id);
                inc_deq(xhci, xhci->event_ring);
                return;
        }

        port = &xhci->hw_ports[port_id - 1];
        if (!port || !port->rhub || port->hcd_portnum == DUPLICATE_ENTRY) {
                xhci_warn(xhci, "Port change event, no port for port ID %u\n",
                          port_id);
                bogus_port_status = true;
                goto cleanup;
        }

        /* We might get interrupts after shared_hcd is removed */
        if (port->rhub == &xhci->usb3_rhub && xhci->shared_hcd == NULL) {
                xhci_dbg(xhci, "ignore port event for removed USB3 hcd\n");
                bogus_port_status = true;
                goto cleanup;
        }

        hcd = port->rhub->hcd;
        bus_state = &port->rhub->bus_state;
        hcd_portnum = port->hcd_portnum;
        portsc = readl(port->addr);

        xhci_dbg(xhci, "Port change event, %d-%d, id %d, portsc: 0x%x\n",
                 hcd->self.busnum, hcd_portnum + 1, port_id, portsc);

        trace_xhci_handle_port_status(hcd_portnum, portsc);

        if (hcd->state == HC_STATE_SUSPENDED) {
                xhci_dbg(xhci, "resume root hub\n");
                usb_hcd_resume_root_hub(hcd);
        }

        if (hcd->speed >= HCD_USB3 &&
            (portsc & PORT_PLS_MASK) == XDEV_INACTIVE) {
                slot_id = xhci_find_slot_id_by_port(hcd, xhci, hcd_portnum + 1);
                if (slot_id && xhci->devs[slot_id])
                        xhci->devs[slot_id]->flags |= VDEV_PORT_ERROR;
        }

        if ((portsc & PORT_PLC) && (portsc & PORT_PLS_MASK) == XDEV_RESUME) {
                xhci_dbg(xhci, "port resume event for port %d\n", port_id);

                cmd_reg = readl(&xhci->op_regs->command);
                if (!(cmd_reg & CMD_RUN)) {
                        xhci_warn(xhci, "xHC is not running.\n");
                        goto cleanup;
                }

                if (DEV_SUPERSPEED_ANY(portsc)) {
                        xhci_dbg(xhci, "remote wake SS port %d\n", port_id);
                        /* Set a flag to say the port signaled remote wakeup,
                         * so we can tell the difference between the end of
                         * device and host initiated resume.
                         */
                        bus_state->port_remote_wakeup |= 1 << hcd_portnum;
                        xhci_test_and_clear_bit(xhci, port, PORT_PLC);
                        usb_hcd_start_port_resume(&hcd->self, hcd_portnum);
                        xhci_set_link_state(xhci, port, XDEV_U0);
                        /* Need to wait until the next link state change
                         * indicates the device is actually in U0.
                         */
                        bogus_port_status = true;
                        goto cleanup;
                } else if (!test_bit(hcd_portnum, &bus_state->resuming_ports)) {
                        xhci_dbg(xhci, "resume HS port %d\n", port_id);
                        bus_state->resume_done[hcd_portnum] = jiffies +
                                msecs_to_jiffies(USB_RESUME_TIMEOUT);
                        set_bit(hcd_portnum, &bus_state->resuming_ports);
                        /* Do the rest in GetPortStatus after resume time delay.
                         * Avoid polling roothub status before that so that a
                         * usb device auto-resume latency around ~40ms.
                         */
                        set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
                        mod_timer(&hcd->rh_timer,
                                  bus_state->resume_done[hcd_portnum]);
                        usb_hcd_start_port_resume(&hcd->self, hcd_portnum);
                        bogus_port_status = true;
                }
        }

        if ((portsc & PORT_PLC) &&
            DEV_SUPERSPEED_ANY(portsc) &&

            ((portsc & PORT_PLS_MASK) == XDEV_U0 ||
             (portsc & PORT_PLS_MASK) == XDEV_U1 ||
             (portsc & PORT_PLS_MASK) == XDEV_U2)) {
                xhci_dbg(xhci, "resume SS port %d finished\n", port_id);
                complete(&bus_state->u3exit_done[hcd_portnum]);
                /* We've just brought the device into U0/1/2 through either the
                 * Resume state after a device remote wakeup, or through the
                 * U3Exit state after a host-initiated resume.  If it's a device
                 * initiated remote wake, don't pass up the link state change,
                 * so the roothub behavior is consistent with external
                 * USB 3.0 hub behavior.
                 */
                slot_id = xhci_find_slot_id_by_port(hcd, xhci, hcd_portnum + 1);
                if (slot_id && xhci->devs[slot_id])
                        xhci_ring_device(xhci, slot_id);
                if (bus_state->port_remote_wakeup & (1 << hcd_portnum)) {
                        xhci_test_and_clear_bit(xhci, port, PORT_PLC);
                        usb_wakeup_notification(hcd->self.root_hub,
                                        hcd_portnum + 1);
                        bogus_port_status = true;
                        goto cleanup;
                }
        }

        /*
         * Check to see if xhci-hub.c is waiting on RExit to U0 transition (or
         * RExit to a disconnect state).  If so, let the the driver know it's
         * out of the RExit state.
         */
        if (!DEV_SUPERSPEED_ANY(portsc) && hcd->speed < HCD_USB3 &&
                        test_and_clear_bit(hcd_portnum,
                                &bus_state->rexit_ports)) {
                complete(&bus_state->rexit_done[hcd_portnum]);
                bogus_port_status = true;
                goto cleanup;
        }

        if (hcd->speed < HCD_USB3) {
                xhci_test_and_clear_bit(xhci, port, PORT_PLC);
                if ((xhci->quirks & XHCI_RESET_PLL_ON_DISCONNECT) &&
                    (portsc & PORT_CSC) && !(portsc & PORT_CONNECT))
                        xhci_cavium_reset_phy_quirk(xhci);
        }

cleanup:
        /* Update event ring dequeue pointer before dropping the lock */
        inc_deq(xhci, xhci->event_ring);

        /* Don't make the USB core poll the roothub if we got a bad port status
         * change event.  Besides, at that point we can't tell which roothub
         * (USB 2.0 or USB 3.0) to kick.
         */
        if (bogus_port_status)
                return;

        /*
         * xHCI port-status-change events occur when the "or" of all the
         * status-change bits in the portsc register changes from 0 to 1.
         * New status changes won't cause an event if any other change
         * bits are still set.  When an event occurs, switch over to
         * polling to avoid losing status changes.
         */
        xhci_dbg(xhci, "%s: starting usb%d port polling.\n",
                 __func__, hcd->self.busnum);
        set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
        spin_unlock(&xhci->lock);
        /* Pass this up to the core */
        usb_hcd_poll_rh_status(hcd);
        spin_lock(&xhci->lock);
}

/*
 * This TD is defined by the TRBs starting at start_trb in start_seg and ending
 * at end_trb, which may be in another segment.  If the suspect DMA address is a
 * TRB in this TD, this function returns that TRB's segment.  Otherwise it
 * returns 0.
 */
struct xhci_segment *trb_in_td(struct xhci_hcd *xhci,
                struct xhci_segment *start_seg,
                union xhci_trb  *start_trb,
                union xhci_trb  *end_trb,
                dma_addr_t      suspect_dma,
                bool            debug)
{
        dma_addr_t start_dma;
        dma_addr_t end_seg_dma;
        dma_addr_t end_trb_dma;
        struct xhci_segment *cur_seg;

        start_dma = xhci_trb_virt_to_dma(start_seg, start_trb);
        cur_seg = start_seg;

        do {
                if (start_dma == 0)
                        return NULL;
                /* We may get an event for a Link TRB in the middle of a TD */
                end_seg_dma = xhci_trb_virt_to_dma(cur_seg,
                                &cur_seg->trbs[TRBS_PER_SEGMENT - 1]);
                /* If the end TRB isn't in this segment, this is set to 0 */
                end_trb_dma = xhci_trb_virt_to_dma(cur_seg, end_trb);

                if (debug)
                        xhci_warn(xhci,
                                "Looking for event-dma %016llx trb-start %016llx trb-end %016llx seg-start %016llx seg-end %016llx\n",
                                (unsigned long long)suspect_dma,
                                (unsigned long long)start_dma,
                                (unsigned long long)end_trb_dma,
                                (unsigned long long)cur_seg->dma,
                                (unsigned long long)end_seg_dma);

                if (end_trb_dma > 0) {
                        /* The end TRB is in this segment, so suspect should be here */
                        if (start_dma <= end_trb_dma) {
                                if (suspect_dma >= start_dma && suspect_dma <= end_trb_dma)
                                        return cur_seg;
                        } else {
                                /* Case for one segment with
                                 * a TD wrapped around to the top
                                 */
                                if ((suspect_dma >= start_dma &&
                                                        suspect_dma <= end_seg_dma) ||
                                                (suspect_dma >= cur_seg->dma &&
                                                 suspect_dma <= end_trb_dma))
                                        return cur_seg;
                        }
                        return NULL;
                } else {
                        /* Might still be somewhere in this segment */
                        if (suspect_dma >= start_dma && suspect_dma <= end_seg_dma)
                                return cur_seg;
                }
                cur_seg = cur_seg->next;
                start_dma = xhci_trb_virt_to_dma(cur_seg, &cur_seg->trbs[0]);
        } while (cur_seg != start_seg);

        return NULL;
}

static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci, struct xhci_td *td,
                struct xhci_virt_ep *ep)
{
        /*
         * As part of low/full-speed endpoint-halt processing
         * we must clear the TT buffer (USB 2.0 specification 11.17.5).
         */
        if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) &&
            (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) &&
            !(ep->ep_state & EP_CLEARING_TT)) {
                ep->ep_state |= EP_CLEARING_TT;
                td->urb->ep->hcpriv = td->urb->dev;
                if (usb_hub_clear_tt_buffer(td->urb))
                        ep->ep_state &= ~EP_CLEARING_TT;
        }
}

/* Check if an error has halted the endpoint ring.  The class driver will
 * cleanup the halt for a non-default control endpoint if we indicate a stall.
 * However, a babble and other errors also halt the endpoint ring, and the class
 * driver won't clear the halt in that case, so we need to issue a Set Transfer
 * Ring Dequeue Pointer command manually.
 */
static int xhci_requires_manual_halt_cleanup(struct xhci_hcd *xhci,
                struct xhci_ep_ctx *ep_ctx,
                unsigned int trb_comp_code)
{
        /* TRB completion codes that may require a manual halt cleanup */
        if (trb_comp_code == COMP_USB_TRANSACTION_ERROR ||
                        trb_comp_code == COMP_BABBLE_DETECTED_ERROR ||
                        trb_comp_code == COMP_SPLIT_TRANSACTION_ERROR)
                /* The 0.95 spec says a babbling control endpoint
                 * is not halted. The 0.96 spec says it is.  Some HW
                 * claims to be 0.95 compliant, but it halts the control
                 * endpoint anyway.  Check if a babble halted the
                 * endpoint.
                 */
                if (GET_EP_CTX_STATE(ep_ctx) == EP_STATE_HALTED)
                        return 1;

        return 0;
}

int xhci_is_vendor_info_code(struct xhci_hcd *xhci, unsigned int trb_comp_code)
{
        if (trb_comp_code >= 224 && trb_comp_code <= 255) {
                /* Vendor defined "informational" completion code,
                 * treat as not-an-error.
                 */
                xhci_dbg(xhci, "Vendor defined info completion code %u\n",
                                trb_comp_code);
                xhci_dbg(xhci, "Treating code as success.\n");
                return 1;
        }
        return 0;
}

static int finish_td(struct xhci_hcd *xhci, struct xhci_virt_ep *ep,
                     struct xhci_ring *ep_ring, struct xhci_td *td,
                     u32 trb_comp_code)
{
        struct xhci_ep_ctx *ep_ctx;

        ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep->ep_index);

        switch (trb_comp_code) {
        case COMP_STOPPED_LENGTH_INVALID:
        case COMP_STOPPED_SHORT_PACKET:
        case COMP_STOPPED:
                /*
                 * The "Stop Endpoint" completion will take care of any
                 * stopped TDs. A stopped TD may be restarted, so don't update
                 * the ring dequeue pointer or take this TD off any lists yet.
                 */
                return 0;
        case COMP_USB_TRANSACTION_ERROR:
        case COMP_BABBLE_DETECTED_ERROR:
        case COMP_SPLIT_TRANSACTION_ERROR:
                /*
                 * If endpoint context state is not halted we might be
                 * racing with a reset endpoint command issued by a unsuccessful
                 * stop endpoint completion (context error). In that case the
                 * td should be on the cancelled list, and EP_HALTED flag set.
                 *
                 * Or then it's not halted due to the 0.95 spec stating that a
                 * babbling control endpoint should not halt. The 0.96 spec
                 * again says it should.  Some HW claims to be 0.95 compliant,
                 * but it halts the control endpoint anyway.
                 */
                if (GET_EP_CTX_STATE(ep_ctx) != EP_STATE_HALTED) {
                        /*
                         * If EP_HALTED is set and TD is on the cancelled list
                         * the TD and dequeue pointer will be handled by reset
                         * ep command completion
                         */
                        if ((ep->ep_state & EP_HALTED) &&
                            !list_empty(&td->cancelled_td_list)) {
                                xhci_dbg(xhci, "Already resolving halted ep for 0x%llx\n",
                                         (unsigned long long)xhci_trb_virt_to_dma(
                                                 td->start_seg, td->first_trb));
                                return 0;
                        }
                        /* endpoint not halted, don't reset it */
                        break;
                }
                /* Almost same procedure as for STALL_ERROR below */
                xhci_clear_hub_tt_buffer(xhci, td, ep);
                xhci_handle_halted_endpoint(xhci, ep, ep_ring->stream_id, td,
                                            EP_HARD_RESET);
                return 0;
        case COMP_STALL_ERROR:
                /*
                 * xhci internal endpoint state will go to a "halt" state for
                 * any stall, including default control pipe protocol stall.
                 * To clear the host side halt we need to issue a reset endpoint
                 * command, followed by a set dequeue command to move past the
                 * TD.
                 * Class drivers clear the device side halt from a functional
                 * stall later. Hub TT buffer should only be cleared for FS/LS
                 * devices behind HS hubs for functional stalls.
                 */
                if (ep->ep_index != 0)
                        xhci_clear_hub_tt_buffer(xhci, td, ep);

                xhci_handle_halted_endpoint(xhci, ep, ep_ring->stream_id, td,
                                            EP_HARD_RESET);

                return 0; /* xhci_handle_halted_endpoint marked td cancelled */
        default:
                break;
        }

        /* Update ring dequeue pointer */
        ep_ring->dequeue = td->last_trb;
        ep_ring->deq_seg = td->last_trb_seg;
        ep_ring->num_trbs_free += td->num_trbs - 1;
        inc_deq(xhci, ep_ring);

        return xhci_td_cleanup(xhci, td, ep_ring, td->status);
}

/* sum trb lengths from ring dequeue up to stop_trb, _excluding_ stop_trb */
static int sum_trb_lengths(struct xhci_hcd *xhci, struct xhci_ring *ring,
                           union xhci_trb *stop_trb)
{
        u32 sum;
        union xhci_trb *trb = ring->dequeue;
        struct xhci_segment *seg = ring->deq_seg;

        for (sum = 0; trb != stop_trb; next_trb(xhci, ring, &seg, &trb)) {
                if (!trb_is_noop(trb) && !trb_is_link(trb))
                        sum += TRB_LEN(le32_to_cpu(trb->generic.field[2]));
        }
        return sum;
}

/*
 * Process control tds, update urb status and actual_length.
 */
static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_virt_ep *ep,
                struct xhci_ring *ep_ring,  struct xhci_td *td,
                           union xhci_trb *ep_trb, struct xhci_transfer_event *event)
{
        struct xhci_ep_ctx *ep_ctx;
        u32 trb_comp_code;
        u32 remaining, requested;
        u32 trb_type;

        trb_type = TRB_FIELD_TO_TYPE(le32_to_cpu(ep_trb->generic.field[3]));
        ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep->ep_index);
        trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
        requested = td->urb->transfer_buffer_length;
        remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));

        switch (trb_comp_code) {
        case COMP_SUCCESS:
                if (trb_type != TRB_STATUS) {
                        xhci_warn(xhci, "WARN: Success on ctrl %s TRB without IOC set?\n",
                                  (trb_type == TRB_DATA) ? "data" : "setup");
                        td->status = -ESHUTDOWN;
                        break;
                }
                td->status = 0;
                break;
        case COMP_SHORT_PACKET:
                td->status = 0;
                break;
        case COMP_STOPPED_SHORT_PACKET:
                if (trb_type == TRB_DATA || trb_type == TRB_NORMAL)
                        td->urb->actual_length = remaining;
                else
                        xhci_warn(xhci, "WARN: Stopped Short Packet on ctrl setup or status TRB\n");
                goto finish_td;
        case COMP_STOPPED:
                switch (trb_type) {
                case TRB_SETUP:
                        td->urb->actual_length = 0;
                        goto finish_td;
                case TRB_DATA:
                case TRB_NORMAL:
                        td->urb->actual_length = requested - remaining;
                        goto finish_td;
                case TRB_STATUS:
                        td->urb->actual_length = requested;
                        goto finish_td;
                default:
                        xhci_warn(xhci, "WARN: unexpected TRB Type %d\n",
                                  trb_type);
                        goto finish_td;
                }
        case COMP_STOPPED_LENGTH_INVALID:
                goto finish_td;
        default:
                if (!xhci_requires_manual_halt_cleanup(xhci,
                                                       ep_ctx, trb_comp_code))
                        break;
                xhci_dbg(xhci, "TRB error %u, halted endpoint index = %u\n",
                         trb_comp_code, ep->ep_index);
                fallthrough;
        case COMP_STALL_ERROR:
                /* Did we transfer part of the data (middle) phase? */
                if (trb_type == TRB_DATA || trb_type == TRB_NORMAL)
                        td->urb->actual_length = requested - remaining;
                else if (!td->urb_length_set)
                        td->urb->actual_length = 0;
                goto finish_td;
        }

        /* stopped at setup stage, no data transferred */
        if (trb_type == TRB_SETUP)
                goto finish_td;

        /*
         * if on data stage then update the actual_length of the URB and flag it
         * as set, so it won't be overwritten in the event for the last TRB.
         */
        if (trb_type == TRB_DATA ||
                trb_type == TRB_NORMAL) {
                td->urb_length_set = true;
                td->urb->actual_length = requested - remaining;
                xhci_dbg(xhci, "Waiting for status stage event\n");
                return 0;
        }

        /* at status stage */
        if (!td->urb_length_set)
                td->urb->actual_length = requested;

finish_td:
        return finish_td(xhci, ep, ep_ring, td, trb_comp_code);
}

/*
 * Process isochronous tds, update urb packet status and actual_length.
 */
static int process_isoc_td(struct xhci_hcd *xhci, struct xhci_virt_ep *ep,
                struct xhci_ring *ep_ring, struct xhci_td *td,
                union xhci_trb *ep_trb, struct xhci_transfer_event *event)
{
        struct urb_priv *urb_priv;
        int idx;
        struct usb_iso_packet_descriptor *frame;
        u32 trb_comp_code;
        bool sum_trbs_for_length = false;
        u32 remaining, requested, ep_trb_len;
        int short_framestatus;

        trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
        urb_priv = td->urb->hcpriv;
        idx = urb_priv->num_tds_done;
        frame = &td->urb->iso_frame_desc[idx];
        requested = frame->length;
        remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
        ep_trb_len = TRB_LEN(le32_to_cpu(ep_trb->generic.field[2]));
        short_framestatus = td->urb->transfer_flags & URB_SHORT_NOT_OK ?
                -EREMOTEIO : 0;

        /* handle completion code */
        switch (trb_comp_code) {
        case COMP_SUCCESS:
                if (remaining) {
                        frame->status = short_framestatus;
                        if (xhci->quirks & XHCI_TRUST_TX_LENGTH)
                                sum_trbs_for_length = true;
                        break;
                }
                frame->status = 0;
                break;
        case COMP_SHORT_PACKET:
                frame->status = short_framestatus;
                sum_trbs_for_length = true;
                break;
        case COMP_BANDWIDTH_OVERRUN_ERROR:
                frame->status = -ECOMM;
                break;
        case COMP_ISOCH_BUFFER_OVERRUN:
        case COMP_BABBLE_DETECTED_ERROR:
                frame->status = -EOVERFLOW;
                break;
        case COMP_INCOMPATIBLE_DEVICE_ERROR:
        case COMP_STALL_ERROR:
                frame->status = -EPROTO;
                break;
        case COMP_USB_TRANSACTION_ERROR:
                frame->status = -EPROTO;
                if (ep_trb != td->last_trb)
                        return 0;
                break;
        case COMP_STOPPED:
                sum_trbs_for_length = true;
                break;
        case COMP_STOPPED_SHORT_PACKET:
                /* field normally containing residue now contains tranferred */
                frame->status = short_framestatus;
                requested = remaining;
                break;
        case COMP_STOPPED_LENGTH_INVALID:
                requested = 0;
                remaining = 0;
                break;
        default:
                sum_trbs_for_length = true;
                frame->status = -1;
                break;
        }

        if (sum_trbs_for_length)
                frame->actual_length = sum_trb_lengths(xhci, ep->ring, ep_trb) +
                        ep_trb_len - remaining;
        else
                frame->actual_length = requested;

        td->urb->actual_length += frame->actual_length;

        return finish_td(xhci, ep, ep_ring, td, trb_comp_code);
}

static int skip_isoc_td(struct xhci_hcd *xhci, struct xhci_td *td,
                        struct xhci_virt_ep *ep, int status)
{
        struct urb_priv *urb_priv;
        struct usb_iso_packet_descriptor *frame;
        int idx;

        urb_priv = td->urb->hcpriv;
        idx = urb_priv->num_tds_done;
        frame = &td->urb->iso_frame_desc[idx];

        /* The transfer is partly done. */
        frame->status = -EXDEV;

        /* calc actual length */
        frame->actual_length = 0;

        /* Update ring dequeue pointer */
        ep->ring->dequeue = td->last_trb;
        ep->ring->deq_seg = td->last_trb_seg;
        ep->ring->num_trbs_free += td->num_trbs - 1;
        inc_deq(xhci, ep->ring);

        return xhci_td_cleanup(xhci, td, ep->ring, status);
}

/*
 * Process bulk and interrupt tds, update urb status and actual_length.
 */
static int process_bulk_intr_td(struct xhci_hcd *xhci, struct xhci_virt_ep *ep,
                struct xhci_ring *ep_ring, struct xhci_td *td,
                union xhci_trb *ep_trb, struct xhci_transfer_event *event)
{
        struct xhci_slot_ctx *slot_ctx;
        u32 trb_comp_code;
        u32 remaining, requested, ep_trb_len;

        slot_ctx = xhci_get_slot_ctx(xhci, ep->vdev->out_ctx);
        trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
        remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
        ep_trb_len = TRB_LEN(le32_to_cpu(ep_trb->generic.field[2]));
        requested = td->urb->transfer_buffer_length;

        switch (trb_comp_code) {
        case COMP_SUCCESS:
                ep_ring->err_count = 0;
                /* handle success with untransferred data as short packet */
                if (ep_trb != td->last_trb || remaining) {
                        xhci_warn(xhci, "WARN Successful completion on short TX\n");
                        xhci_dbg(xhci, "ep %#x - asked for %d bytes, %d bytes untransferred\n",
                                 td->urb->ep->desc.bEndpointAddress,
                                 requested, remaining);
                }
                td->status = 0;
                break;
        case COMP_SHORT_PACKET:
                xhci_dbg(xhci, "ep %#x - asked for %d bytes, %d bytes untransferred\n",
                         td->urb->ep->desc.bEndpointAddress,
                         requested, remaining);
                td->status = 0;
                break;
        case COMP_STOPPED_SHORT_PACKET:
                td->urb->actual_length = remaining;
                goto finish_td;
        case COMP_STOPPED_LENGTH_INVALID:
                /* stopped on ep trb with invalid length, exclude it */
                ep_trb_len      = 0;
                remaining       = 0;
                break;
        case COMP_USB_TRANSACTION_ERROR:
                if (xhci->quirks & XHCI_NO_SOFT_RETRY ||
                    (ep_ring->err_count++ > MAX_SOFT_RETRY) ||
                    le32_to_cpu(slot_ctx->tt_info) & TT_SLOT)
                        break;

                td->status = 0;

                xhci_handle_halted_endpoint(xhci, ep, ep_ring->stream_id, td,
                                            EP_SOFT_RESET);
                return 0;
        default:
                /* do nothing */
                break;
        }

        if (ep_trb == td->last_trb)
                td->urb->actual_length = requested - remaining;
        else
                td->urb->actual_length =
                        sum_trb_lengths(xhci, ep_ring, ep_trb) +
                        ep_trb_len - remaining;
finish_td:
        if (remaining > requested) {
                xhci_warn(xhci, "bad transfer trb length %d in event trb\n",
                          remaining);
                td->urb->actual_length = 0;
        }

        return finish_td(xhci, ep, ep_ring, td, trb_comp_code);
}

/*
 * If this function returns an error condition, it means it got a Transfer
 * event with a corrupted Slot ID, Endpoint ID, or TRB DMA address.
 * At this point, the host controller is probably hosed and should be reset.
 */
static int handle_tx_event(struct xhci_hcd *xhci,
                struct xhci_transfer_event *event)
{
        struct xhci_virt_ep *ep;
        struct xhci_ring *ep_ring;
        unsigned int slot_id;
        int ep_index;
        struct xhci_td *td = NULL;
        dma_addr_t ep_trb_dma;
        struct xhci_segment *ep_seg;
        union xhci_trb *ep_trb;
        int status = -EINPROGRESS;
        struct xhci_ep_ctx *ep_ctx;
        struct list_head *tmp;
        u32 trb_comp_code;
        int td_num = 0;
        bool handling_skipped_tds = false;

        slot_id = TRB_TO_SLOT_ID(le32_to_cpu(event->flags));
        ep_index = TRB_TO_EP_ID(le32_to_cpu(event->flags)) - 1;
        trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
        ep_trb_dma = le64_to_cpu(event->buffer);

        ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
        if (!ep) {
                xhci_err(xhci, "ERROR Invalid Transfer event\n");
                goto err_out;
        }

        ep_ring = xhci_dma_to_transfer_ring(ep, ep_trb_dma);
        ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep_index);

        if (GET_EP_CTX_STATE(ep_ctx) == EP_STATE_DISABLED) {
                xhci_err(xhci,
                         "ERROR Transfer event for disabled endpoint slot %u ep %u\n",
                          slot_id, ep_index);
                goto err_out;
        }

        /* Some transfer events don't always point to a trb, see xhci 4.17.4 */
        if (!ep_ring) {
                switch (trb_comp_code) {
                case COMP_STALL_ERROR:
                case COMP_USB_TRANSACTION_ERROR:
                case COMP_INVALID_STREAM_TYPE_ERROR:
                case COMP_INVALID_STREAM_ID_ERROR:
                        xhci_handle_halted_endpoint(xhci, ep, 0, NULL,
                                                    EP_SOFT_RESET);
                        goto cleanup;
                case COMP_RING_UNDERRUN:
                case COMP_RING_OVERRUN:
                case COMP_STOPPED_LENGTH_INVALID:
                        goto cleanup;
                default:
                        xhci_err(xhci, "ERROR Transfer event for unknown stream ring slot %u ep %u\n",
                                 slot_id, ep_index);
                        goto err_out;
                }
        }

        /* Count current td numbers if ep->skip is set */
        if (ep->skip) {
                list_for_each(tmp, &ep_ring->td_list)
                        td_num++;
        }

        /* Look for common error cases */
        switch (trb_comp_code) {
        /* Skip codes that require special handling depending on
         * transfer type
         */
        case COMP_SUCCESS:
                if (EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)) == 0)
                        break;
                if (xhci->quirks & XHCI_TRUST_TX_LENGTH ||
                    ep_ring->last_td_was_short)
                        trb_comp_code = COMP_SHORT_PACKET;
                else
                        xhci_warn_ratelimited(xhci,
                                              "WARN Successful completion on short TX for slot %u ep %u: needs XHCI_TRUST_TX_LENGTH quirk?\n",
                                              slot_id, ep_index);
                break;
        case COMP_SHORT_PACKET:
                break;
        /* Completion codes for endpoint stopped state */
        case COMP_STOPPED:
                xhci_dbg(xhci, "Stopped on Transfer TRB for slot %u ep %u\n",
                         slot_id, ep_index);
                break;
        case COMP_STOPPED_LENGTH_INVALID:
                xhci_dbg(xhci,
                         "Stopped on No-op or Link TRB for slot %u ep %u\n",
                         slot_id, ep_index);
                break;
        case COMP_STOPPED_SHORT_PACKET:
                xhci_dbg(xhci,
                         "Stopped with short packet transfer detected for slot %u ep %u\n",
                         slot_id, ep_index);
                break;
        /* Completion codes for endpoint halted state */
        case COMP_STALL_ERROR:
                xhci_dbg(xhci, "Stalled endpoint for slot %u ep %u\n", slot_id,
                         ep_index);
                status = -EPIPE;
                break;
        case COMP_SPLIT_TRANSACTION_ERROR:
                xhci_dbg(xhci, "Split transaction error for slot %u ep %u\n",
                         slot_id, ep_index);
                status = -EPROTO;
                break;
        case COMP_USB_TRANSACTION_ERROR:
                xhci_dbg(xhci, "Transfer error for slot %u ep %u on endpoint\n",
                         slot_id, ep_index);
                status = -EPROTO;
                break;
        case COMP_BABBLE_DETECTED_ERROR:
                xhci_dbg(xhci, "Babble error for slot %u ep %u on endpoint\n",
                         slot_id, ep_index);
                status = -EOVERFLOW;
                break;
        /* Completion codes for endpoint error state */
        case COMP_TRB_ERROR:
                xhci_warn(xhci,
                          "WARN: TRB error for slot %u ep %u on endpoint\n",
                          slot_id, ep_index);
                status = -EILSEQ;
                break;
        /* completion codes not indicating endpoint state change */
        case COMP_DATA_BUFFER_ERROR:
                xhci_warn(xhci,
                          "WARN: HC couldn't access mem fast enough for slot %u ep %u\n",
                          slot_id, ep_index);
                status = -ENOSR;
                break;
        case COMP_BANDWIDTH_OVERRUN_ERROR:
                xhci_warn(xhci,
                          "WARN: bandwidth overrun event for slot %u ep %u on endpoint\n",
                          slot_id, ep_index);
                break;
        case COMP_ISOCH_BUFFER_OVERRUN:
                xhci_warn(xhci,
                          "WARN: buffer overrun event for slot %u ep %u on endpoint",
                          slot_id, ep_index);
                break;
        case COMP_RING_UNDERRUN:
                /*
                 * When the Isoch ring is empty, the xHC will generate
                 * a Ring Overrun Event for IN Isoch endpoint or Ring
                 * Underrun Event for OUT Isoch endpoint.
                 */
                xhci_dbg(xhci, "underrun event on endpoint\n");
                if (!list_empty(&ep_ring->td_list))
                        xhci_dbg(xhci, "Underrun Event for slot %d ep %d "
                                        "still with TDs queued?\n",
                                 TRB_TO_SLOT_ID(le32_to_cpu(event->flags)),
                                 ep_index);
                goto cleanup;
        case COMP_RING_OVERRUN:
                xhci_dbg(xhci, "overrun event on endpoint\n");
                if (!list_empty(&ep_ring->td_list))
                        xhci_dbg(xhci, "Overrun Event for slot %d ep %d "
                                        "still with TDs queued?\n",
                                 TRB_TO_SLOT_ID(le32_to_cpu(event->flags)),
                                 ep_index);
                goto cleanup;
        case COMP_MISSED_SERVICE_ERROR:
                /*
                 * When encounter missed service error, one or more isoc tds
                 * may be missed by xHC.
                 * Set skip flag of the ep_ring; Complete the missed tds as
                 * short transfer when process the ep_ring next time.
                 */
                ep->skip = true;
                xhci_dbg(xhci,
                         "Miss service interval error for slot %u ep %u, set skip flag\n",
                         slot_id, ep_index);
                goto cleanup;
        case COMP_NO_PING_RESPONSE_ERROR:
                ep->skip = true;
                xhci_dbg(xhci,
                         "No Ping response error for slot %u ep %u, Skip one Isoc TD\n",
                         slot_id, ep_index);
                goto cleanup;

        case COMP_INCOMPATIBLE_DEVICE_ERROR:
                /* needs disable slot command to recover */
                xhci_warn(xhci,
                          "WARN: detect an incompatible device for slot %u ep %u",
                          slot_id, ep_index);
                status = -EPROTO;
                break;
        default:
                if (xhci_is_vendor_info_code(xhci, trb_comp_code)) {
                        status = 0;
                        break;
                }
                xhci_warn(xhci,
                          "ERROR Unknown event condition %u for slot %u ep %u , HC probably busted\n",
                          trb_comp_code, slot_id, ep_index);
                goto cleanup;
        }

        do {
                /* This TRB should be in the TD at the head of this ring's
                 * TD list.
                 */
                if (list_empty(&ep_ring->td_list)) {
                        /*
                         * Don't print wanings if it's due to a stopped endpoint
                         * generating an extra completion event if the device
                         * was suspended. Or, a event for the last TRB of a
                         * short TD we already got a short event for.
                         * The short TD is already removed from the TD list.
                         */

                        if (!(trb_comp_code == COMP_STOPPED ||
                              trb_comp_code == COMP_STOPPED_LENGTH_INVALID ||
                              ep_ring->last_td_was_short)) {
                                xhci_warn(xhci, "WARN Event TRB for slot %d ep %d with no TDs queued?\n",
                                                TRB_TO_SLOT_ID(le32_to_cpu(event->flags)),
                                                ep_index);
                        }
                        if (ep->skip) {
                                ep->skip = false;
                                xhci_dbg(xhci, "td_list is empty while skip flag set. Clear skip flag for slot %u ep %u.\n",
                                         slot_id, ep_index);
                        }
                        if (trb_comp_code == COMP_STALL_ERROR ||
                            xhci_requires_manual_halt_cleanup(xhci, ep_ctx,
                                                              trb_comp_code)) {
                                xhci_handle_halted_endpoint(xhci, ep,
                                                            ep_ring->stream_id,
                                                            NULL,
                                                            EP_HARD_RESET);
                        }
                        goto cleanup;
                }

                /* We've skipped all the TDs on the ep ring when ep->skip set */
                if (ep->skip && td_num == 0) {
                        ep->skip = false;
                        xhci_dbg(xhci, "All tds on the ep_ring skipped. Clear skip flag for slot %u ep %u.\n",
                                 slot_id, ep_index);
                        goto cleanup;
                }

                td = list_first_entry(&ep_ring->td_list, struct xhci_td,
                                      td_list);
                if (ep->skip)
                        td_num--;

                /* Is this a TRB in the currently executing TD? */
                ep_seg = trb_in_td(xhci, ep_ring->deq_seg, ep_ring->dequeue,
                                td->last_trb, ep_trb_dma, false);

                /*
                 * Skip the Force Stopped Event. The event_trb(event_dma) of FSE
                 * is not in the current TD pointed by ep_ring->dequeue because
                 * that the hardware dequeue pointer still at the previous TRB
                 * of the current TD. The previous TRB maybe a Link TD or the
                 * last TRB of the previous TD. The command completion handle
                 * will take care the rest.
                 */
                if (!ep_seg && (trb_comp_code == COMP_STOPPED ||
                           trb_comp_code == COMP_STOPPED_LENGTH_INVALID)) {
                        goto cleanup;
                }

                if (!ep_seg) {
                        if (!ep->skip ||
                            !usb_endpoint_xfer_isoc(&td->urb->ep->desc)) {
                                /* Some host controllers give a spurious
                                 * successful event after a short transfer.
                                 * Ignore it.
                                 */
                                if ((xhci->quirks & XHCI_SPURIOUS_SUCCESS) &&
                                                ep_ring->last_td_was_short) {
                                        ep_ring->last_td_was_short = false;
                                        goto cleanup;
                                }
                                /* HC is busted, give up! */
                                xhci_err(xhci,
                                        "ERROR Transfer event TRB DMA ptr not "
                                        "part of current TD ep_index %d "
                                        "comp_code %u\n", ep_index,
                                        trb_comp_code);
                                trb_in_td(xhci, ep_ring->deq_seg,
                                          ep_ring->dequeue, td->last_trb,
                                          ep_trb_dma, true);
                                return -ESHUTDOWN;
                        }

                        skip_isoc_td(xhci, td, ep, status);
                        goto cleanup;
                }
                if (trb_comp_code == COMP_SHORT_PACKET)
                        ep_ring->last_td_was_short = true;
                else
                        ep_ring->last_td_was_short = false;

                if (ep->skip) {
                        xhci_dbg(xhci,
                                 "Found td. Clear skip flag for slot %u ep %u.\n",
                                 slot_id, ep_index);
                        ep->skip = false;
                }

                ep_trb = &ep_seg->trbs[(ep_trb_dma - ep_seg->dma) /
                                                sizeof(*ep_trb)];

                trace_xhci_handle_transfer(ep_ring,
                                (struct xhci_generic_trb *) ep_trb);

                /*
                 * No-op TRB could trigger interrupts in a case where
                 * a URB was killed and a STALL_ERROR happens right
                 * after the endpoint ring stopped. Reset the halted
                 * endpoint. Otherwise, the endpoint remains stalled
                 * indefinitely.
                 */

                if (trb_is_noop(ep_trb)) {
                        if (trb_comp_code == COMP_STALL_ERROR ||
                            xhci_requires_manual_halt_cleanup(xhci, ep_ctx,
                                                              trb_comp_code))
                                xhci_handle_halted_endpoint(xhci, ep,
                                                            ep_ring->stream_id,
                                                            td, EP_HARD_RESET);
                        goto cleanup;
                }

                td->status = status;

                /* update the urb's actual_length and give back to the core */
                if (usb_endpoint_xfer_control(&td->urb->ep->desc))
                        process_ctrl_td(xhci, ep, ep_ring, td, ep_trb, event);
                else if (usb_endpoint_xfer_isoc(&td->urb->ep->desc))
                        process_isoc_td(xhci, ep, ep_ring, td, ep_trb, event);
                else
                        process_bulk_intr_td(xhci, ep, ep_ring, td, ep_trb, event);
cleanup:
                handling_skipped_tds = ep->skip &&
                        trb_comp_code != COMP_MISSED_SERVICE_ERROR &&
                        trb_comp_code != COMP_NO_PING_RESPONSE_ERROR;

                /*
                 * Do not update event ring dequeue pointer if we're in a loop
                 * processing missed tds.
                 */
                if (!handling_skipped_tds)
                        inc_deq(xhci, xhci->event_ring);

        /*
         * If ep->skip is set, it means there are missed tds on the
         * endpoint ring need to take care of.
         * Process them as short transfer until reach the td pointed by
         * the event.
         */
        } while (handling_skipped_tds);

        return 0;

err_out:
        xhci_err(xhci, "@%016llx %08x %08x %08x %08x\n",
                 (unsigned long long) xhci_trb_virt_to_dma(
                         xhci->event_ring->deq_seg,
                         xhci->event_ring->dequeue),
                 lower_32_bits(le64_to_cpu(event->buffer)),
                 upper_32_bits(le64_to_cpu(event->buffer)),
                 le32_to_cpu(event->transfer_len),
                 le32_to_cpu(event->flags));
        return -ENODEV;
}

/*
 * This function handles all OS-owned events on the event ring.  It may drop
 * xhci->lock between event processing (e.g. to pass up port status changes).
 * Returns >0 for "possibly more events to process" (caller should call again),
 * otherwise 0 if done.  In future, <0 returns should indicate error code.
 */
static int xhci_handle_event(struct xhci_hcd *xhci)
{
        union xhci_trb *event;
        int update_ptrs = 1;
        u32 trb_type;
        int ret;

        /* Event ring hasn't been allocated yet. */
        if (!xhci->event_ring || !xhci->event_ring->dequeue) {
                xhci_err(xhci, "ERROR event ring not ready\n");
                return -ENOMEM;
        }

        event = xhci->event_ring->dequeue;
        /* Does the HC or OS own the TRB? */
        if ((le32_to_cpu(event->event_cmd.flags) & TRB_CYCLE) !=
            xhci->event_ring->cycle_state)
                return 0;

        trace_xhci_handle_event(xhci->event_ring, &event->generic);

        /*
         * Barrier between reading the TRB_CYCLE (valid) flag above and any
         * speculative reads of the event's flags/data below.
         */
        rmb();
        trb_type = TRB_FIELD_TO_TYPE(le32_to_cpu(event->event_cmd.flags));
        /* FIXME: Handle more event types. */

        switch (trb_type) {
        case TRB_COMPLETION:
                handle_cmd_completion(xhci, &event->event_cmd);
                break;
        case TRB_PORT_STATUS:
                handle_port_status(xhci, event);
                update_ptrs = 0;
                break;
        case TRB_TRANSFER:
                ret = handle_tx_event(xhci, &event->trans_event);