Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4385 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
new file mode 100644
index 000000000..1239e06df
--- /dev/null
+++ b/drivers/usb/host/xhci-ring.c
@@ -0,0 +1,4385 @@
+// 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);
+}
+
+static int xhci_num_trbs_to(struct xhci_segment *start_seg, union xhci_trb *start,
+			    struct xhci_segment *end_seg, union xhci_trb *end,
+			    unsigned int num_segs)
+{
+	union xhci_trb *last_on_seg;
+	int num = 0;
+	int i = 0;
+
+	do {
+		if (start_seg == end_seg && end >= start)
+			return num + (end - start);
+		last_on_seg = &start_seg->trbs[TRBS_PER_SEGMENT - 1];
+		num += last_on_seg - start;
+		start_seg = start_seg->next;
+		start = start_seg->trbs;
+	} while (i++ <= num_segs);
+
+	return -EINVAL;
+}
+
+/*
+ * 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)
+{
+	struct xhci_segment *new_seg	= xhci->cmd_ring->deq_seg;
+	union xhci_trb *new_deq		= xhci->cmd_ring->dequeue;
+	u64 crcr;
+	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.
+	 * Some controllers require all 64 bits to be written to abort the ring.
+	 * Make sure the upper dword is valid, pointing to the next command,
+	 * avoiding corrupting the command ring pointer in case the command ring
+	 * is stopped by the time the upper dword is written.
+	 */
+	next_trb(xhci, NULL, &new_seg, &new_deq);
+	if (trb_is_link(new_deq))
+		next_trb(xhci, NULL, &new_seg, &new_deq);
+
+	crcr = xhci_trb_virt_to_dma(new_seg, new_deq);
+	xhci_write_64(xhci, crcr | 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;
+	union xhci_trb *new_deq;
+	int new_cycle;
+	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;
+	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);
+	}
+}
+
+/*
+ * 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.sysdev;
+	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;
+			ep->ep_state &= ~EP_STOP_CMD_PENDING;
+			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) {
+				ep->ep_state &= ~EP_STOP_CMD_PENDING;
+				return;
+			}
+			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);
+	ep->ep_state &= ~EP_STOP_CMD_PENDING;
+
+	/* 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_get_virt_ep(xhci, slot_id, ep_index);
+	if (!ep)
+		return;
+
+	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));
+}
+
+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);
+
+	/* 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);
+}
+
+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;
+	u32 add_flags;
+
+	/*
+	 * Configure endpoint commands can come from the USB core configuration
+	 * or alt setting changes, or when streams were being configured.
+	 */
+
+	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);
+
+	/* 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);
+
+	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;
+	char		str[XHCI_MSG_MAX];
+	u64		hw_ring_state;
+	u32		cmd_field3;
+	u32		usbsts;
+
+	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;
+	}
+
+	cmd_field3 = le32_to_cpu(xhci->current_cmd->command_trb->generic.field[3]);
+	usbsts = readl(&xhci->op_regs->status);
+	xhci_dbg(xhci, "Command timeout, USBSTS:%s\n", xhci_decode_usbsts(str, usbsts));
+
+	/* Bail out and tear down xhci if a stop endpoint command failed */
+	if (TRB_FIELD_TO_TYPE(cmd_field3) == TRB_STOP_RING) {
+		struct xhci_virt_ep	*ep;
+
+		xhci_warn(xhci, "xHCI host not responding to stop endpoint command\n");
+
+		ep = xhci_get_virt_ep(xhci, TRB_TO_SLOT_ID(cmd_field3),
+				      TRB_TO_EP_INDEX(cmd_field3));
+		if (ep)
+			ep->ep_state &= ~EP_STOP_CMD_PENDING;
+
+		xhci_halt(xhci);
+		xhci_hc_died(xhci);
+		goto time_out_completed;
+	}
+
+	/* 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 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;
+	int trbs_freed;
+
+	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 */
+	trbs_freed = xhci_num_trbs_to(ep_ring->deq_seg, ep_ring->dequeue,
+				      td->last_trb_seg, td->last_trb,
+				      ep_ring->num_segs);
+	if (trbs_freed < 0)
+		xhci_dbg(xhci, "Failed to count freed trbs at TD finish\n");
+	else
+		ep_ring->num_trbs_free += trbs_freed;
+	ep_ring->dequeue = td->last_trb;
+	ep_ring->deq_seg = td->last_trb_seg;
+	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->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->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_dbg(xhci, "Stream transaction error ep %u no id\n",
+				 ep_index);
+			if (ep->err_count++ > MAX_SOFT_RETRY)
+				xhci_handle_halted_endpoint(xhci, ep, 0, NULL,
+							    EP_HARD_RESET);
+			else
+				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);
+		if (ret >= 0)
+			update_ptrs = 0;
+		break;
+	case TRB_DEV_NOTE:
+		handle_device_notification(xhci, event);
+		break;
+	default:
+		if (trb_type >= TRB_VENDOR_DEFINED_LOW)
+			handle_vendor_event(xhci, event, trb_type);
+		else
+			xhci_warn(xhci, "ERROR unknown event type %d\n", trb_type);
+	}
+	/* Any of the above functions may drop and re-acquire the lock, so check
+	 * to make sure a watchdog timer didn't mark the host as non-responsive.
+	 */
+	if (xhci->xhc_state & XHCI_STATE_DYING) {
+		xhci_dbg(xhci, "xHCI host dying, returning from "
+				"event handler.\n");
+		return 0;
+	}
+
+	if (update_ptrs)
+		/* Update SW event ring dequeue pointer */
+		inc_deq(xhci, xhci->event_ring);
+
+	/* Are there more items on the event ring?  Caller will call us again to
+	 * check.
+	 */
+	return 1;
+}
+
+/*
+ * Update Event Ring Dequeue Pointer:
+ * - When all events have finished
+ * - To avoid "Event Ring Full Error" condition
+ */
+static void xhci_update_erst_dequeue(struct xhci_hcd *xhci,
+		union xhci_trb *event_ring_deq)
+{
+	u64 temp_64;
+	dma_addr_t deq;
+
+	temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
+	/* If necessary, update the HW's version of the event ring deq ptr. */
+	if (event_ring_deq != xhci->event_ring->dequeue) {
+		deq = xhci_trb_virt_to_dma(xhci->event_ring->deq_seg,
+				xhci->event_ring->dequeue);
+		if (deq == 0)
+			xhci_warn(xhci, "WARN something wrong with SW event ring dequeue ptr\n");
+		/*
+		 * Per 4.9.4, Software writes to the ERDP register shall
+		 * always advance the Event Ring Dequeue Pointer value.
+		 */
+		if ((temp_64 & (u64) ~ERST_PTR_MASK) ==
+				((u64) deq & (u64) ~ERST_PTR_MASK))
+			return;
+
+		/* Update HC event ring dequeue pointer */
+		temp_64 &= ERST_PTR_MASK;
+		temp_64 |= ((u64) deq & (u64) ~ERST_PTR_MASK);
+	}
+
+	/* Clear the event handler busy flag (RW1C) */
+	temp_64 |= ERST_EHB;
+	xhci_write_64(xhci, temp_64, &xhci->ir_set->erst_dequeue);
+}
+
+/*
+ * xHCI spec says we can get an interrupt, and if the HC has an error condition,
+ * we might get bad data out of the event ring.  Section 4.10.2.7 has a list of
+ * indicators of an event TRB error, but we check the status *first* to be safe.
+ */
+irqreturn_t xhci_irq(struct usb_hcd *hcd)
+{
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	union xhci_trb *event_ring_deq;
+	irqreturn_t ret = IRQ_NONE;
+	u64 temp_64;
+	u32 status;
+	int event_loop = 0;
+
+	spin_lock(&xhci->lock);
+	/* Check if the xHC generated the interrupt, or the irq is shared */
+	status = readl(&xhci->op_regs->status);
+	if (status == ~(u32)0) {
+		xhci_hc_died(xhci);
+		ret = IRQ_HANDLED;
+		goto out;
+	}
+
+	if (!(status & STS_EINT))
+		goto out;
+
+	if (status & STS_FATAL) {
+		xhci_warn(xhci, "WARNING: Host System Error\n");
+		xhci_halt(xhci);
+		ret = IRQ_HANDLED;
+		goto out;
+	}
+
+	/*
+	 * Clear the op reg interrupt status first,
+	 * so we can receive interrupts from other MSI-X interrupters.
+	 * Write 1 to clear the interrupt status.
+	 */
+	status |= STS_EINT;
+	writel(status, &xhci->op_regs->status);
+
+	if (!hcd->msi_enabled) {
+		u32 irq_pending;
+		irq_pending = readl(&xhci->ir_set->irq_pending);
+		irq_pending |= IMAN_IP;
+		writel(irq_pending, &xhci->ir_set->irq_pending);
+	}
+
+	if (xhci->xhc_state & XHCI_STATE_DYING ||
+	    xhci->xhc_state & XHCI_STATE_HALTED) {
+		xhci_dbg(xhci, "xHCI dying, ignoring interrupt. "
+				"Shouldn't IRQs be disabled?\n");
+		/* Clear the event handler busy flag (RW1C);
+		 * the event ring should be empty.
+		 */
+		temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
+		xhci_write_64(xhci, temp_64 | ERST_EHB,
+				&xhci->ir_set->erst_dequeue);
+		ret = IRQ_HANDLED;
+		goto out;
+	}
+
+	event_ring_deq = xhci->event_ring->dequeue;
+	/* FIXME this should be a delayed service routine
+	 * that clears the EHB.
+	 */
+	while (xhci_handle_event(xhci) > 0) {
+		if (event_loop++ < TRBS_PER_SEGMENT / 2)
+			continue;
+		xhci_update_erst_dequeue(xhci, event_ring_deq);
+		event_ring_deq = xhci->event_ring->dequeue;
+
+		/* ring is half-full, force isoc trbs to interrupt more often */
+		if (xhci->isoc_bei_interval > AVOID_BEI_INTERVAL_MIN)
+			xhci->isoc_bei_interval = xhci->isoc_bei_interval / 2;
+
+		event_loop = 0;
+	}
+
+	xhci_update_erst_dequeue(xhci, event_ring_deq);
+	ret = IRQ_HANDLED;
+
+out:
+	spin_unlock(&xhci->lock);
+
+	return ret;
+}
+
+irqreturn_t xhci_msi_irq(int irq, void *hcd)
+{
+	return xhci_irq(hcd);
+}
+
+/****		Endpoint Ring Operations	****/
+
+/*
+ * Generic function for queueing a TRB on a ring.
+ * The caller must have checked to make sure there's room on the ring.
+ *
+ * @more_trbs_coming:	Will you enqueue more TRBs before calling
+ *			prepare_transfer()?
+ */
+static void queue_trb(struct xhci_hcd *xhci, struct xhci_ring *ring,
+		bool more_trbs_coming,
+		u32 field1, u32 field2, u32 field3, u32 field4)
+{
+	struct xhci_generic_trb *trb;
+
+	trb = &ring->enqueue->generic;
+	trb->field[0] = cpu_to_le32(field1);
+	trb->field[1] = cpu_to_le32(field2);
+	trb->field[2] = cpu_to_le32(field3);
+	/* make sure TRB is fully written before giving it to the controller */
+	wmb();
+	trb->field[3] = cpu_to_le32(field4);
+
+	trace_xhci_queue_trb(ring, trb);
+
+	inc_enq(xhci, ring, more_trbs_coming);
+}
+
+/*
+ * Does various checks on the endpoint ring, and makes it ready to queue num_trbs.
+ * FIXME allocate segments if the ring is full.
+ */
+static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
+		u32 ep_state, unsigned int num_trbs, gfp_t mem_flags)
+{
+	unsigned int num_trbs_needed;
+	unsigned int link_trb_count = 0;
+
+	/* Make sure the endpoint has been added to xHC schedule */
+	switch (ep_state) {
+	case EP_STATE_DISABLED:
+		/*
+		 * USB core changed config/interfaces without notifying us,
+		 * or hardware is reporting the wrong state.
+		 */
+		xhci_warn(xhci, "WARN urb submitted to disabled ep\n");
+		return -ENOENT;
+	case EP_STATE_ERROR:
+		xhci_warn(xhci, "WARN waiting for error on ep to be cleared\n");
+		/* FIXME event handling code for error needs to clear it */
+		/* XXX not sure if this should be -ENOENT or not */
+		return -EINVAL;
+	case EP_STATE_HALTED:
+		xhci_dbg(xhci, "WARN halted endpoint, queueing URB anyway.\n");
+		break;
+	case EP_STATE_STOPPED:
+	case EP_STATE_RUNNING:
+		break;
+	default:
+		xhci_err(xhci, "ERROR unknown endpoint state for ep\n");
+		/*
+		 * FIXME issue Configure Endpoint command to try to get the HC
+		 * back into a known state.
+		 */
+		return -EINVAL;
+	}
+
+	while (1) {
+		if (room_on_ring(xhci, ep_ring, num_trbs))
+			break;
+
+		if (ep_ring == xhci->cmd_ring) {
+			xhci_err(xhci, "Do not support expand command ring\n");
+			return -ENOMEM;
+		}
+
+		xhci_dbg_trace(xhci, trace_xhci_dbg_ring_expansion,
+				"ERROR no room on ep ring, try ring expansion");
+		num_trbs_needed = num_trbs - ep_ring->num_trbs_free;
+		if (xhci_ring_expansion(xhci, ep_ring, num_trbs_needed,
+					mem_flags)) {
+			xhci_err(xhci, "Ring expansion failed\n");
+			return -ENOMEM;
+		}
+	}
+
+	while (trb_is_link(ep_ring->enqueue)) {
+		/* If we're not dealing with 0.95 hardware or isoc rings
+		 * on AMD 0.96 host, clear the chain bit.
+		 */
+		if (!xhci_link_trb_quirk(xhci) &&
+		    !(ep_ring->type == TYPE_ISOC &&
+		      (xhci->quirks & XHCI_AMD_0x96_HOST)))
+			ep_ring->enqueue->link.control &=
+				cpu_to_le32(~TRB_CHAIN);
+		else
+			ep_ring->enqueue->link.control |=
+				cpu_to_le32(TRB_CHAIN);
+
+		wmb();
+		ep_ring->enqueue->link.control ^= cpu_to_le32(TRB_CYCLE);
+
+		/* Toggle the cycle bit after the last ring segment. */
+		if (link_trb_toggles_cycle(ep_ring->enqueue))
+			ep_ring->cycle_state ^= 1;
+
+		ep_ring->enq_seg = ep_ring->enq_seg->next;
+		ep_ring->enqueue = ep_ring->enq_seg->trbs;
+
+		/* prevent infinite loop if all first trbs are link trbs */
+		if (link_trb_count++ > ep_ring->num_segs) {
+			xhci_warn(xhci, "Ring is an endless link TRB loop\n");
+			return -EINVAL;
+		}
+	}
+
+	if (last_trb_on_seg(ep_ring->enq_seg, ep_ring->enqueue)) {
+		xhci_warn(xhci, "Missing link TRB at end of ring segment\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int prepare_transfer(struct xhci_hcd *xhci,
+		struct xhci_virt_device *xdev,
+		unsigned int ep_index,
+		unsigned int stream_id,
+		unsigned int num_trbs,
+		struct urb *urb,
+		unsigned int td_index,
+		gfp_t mem_flags)
+{
+	int ret;
+	struct urb_priv *urb_priv;
+	struct xhci_td	*td;
+	struct xhci_ring *ep_ring;
+	struct xhci_ep_ctx *ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
+
+	ep_ring = xhci_triad_to_transfer_ring(xhci, xdev->slot_id, ep_index,
+					      stream_id);
+	if (!ep_ring) {
+		xhci_dbg(xhci, "Can't prepare ring for bad stream ID %u\n",
+				stream_id);
+		return -EINVAL;
+	}
+
+	ret = prepare_ring(xhci, ep_ring, GET_EP_CTX_STATE(ep_ctx),
+			   num_trbs, mem_flags);
+	if (ret)
+		return ret;
+
+	urb_priv = urb->hcpriv;
+	td = &urb_priv->td[td_index];
+
+	INIT_LIST_HEAD(&td->td_list);
+	INIT_LIST_HEAD(&td->cancelled_td_list);
+
+	if (td_index == 0) {
+		ret = usb_hcd_link_urb_to_ep(bus_to_hcd(urb->dev->bus), urb);
+		if (unlikely(ret))
+			return ret;
+	}
+
+	td->urb = urb;
+	/* Add this TD to the tail of the endpoint ring's TD list */
+	list_add_tail(&td->td_list, &ep_ring->td_list);
+	td->start_seg = ep_ring->enq_seg;
+	td->first_trb = ep_ring->enqueue;
+
+	return 0;
+}
+
+unsigned int count_trbs(u64 addr, u64 len)
+{
+	unsigned int num_trbs;
+
+	num_trbs = DIV_ROUND_UP(len + (addr & (TRB_MAX_BUFF_SIZE - 1)),
+			TRB_MAX_BUFF_SIZE);
+	if (num_trbs == 0)
+		num_trbs++;
+
+	return num_trbs;
+}
+
+static inline unsigned int count_trbs_needed(struct urb *urb)
+{
+	return count_trbs(urb->transfer_dma, urb->transfer_buffer_length);
+}
+
+static unsigned int count_sg_trbs_needed(struct urb *urb)
+{
+	struct scatterlist *sg;
+	unsigned int i, len, full_len, num_trbs = 0;
+
+	full_len = urb->transfer_buffer_length;
+
+	for_each_sg(urb->sg, sg, urb->num_mapped_sgs, i) {
+		len = sg_dma_len(sg);
+		num_trbs += count_trbs(sg_dma_address(sg), len);
+		len = min_t(unsigned int, len, full_len);
+		full_len -= len;
+		if (full_len == 0)
+			break;
+	}
+
+	return num_trbs;
+}
+
+static unsigned int count_isoc_trbs_needed(struct urb *urb, int i)
+{
+	u64 addr, len;
+
+	addr = (u64) (urb->transfer_dma + urb->iso_frame_desc[i].offset);
+	len = urb->iso_frame_desc[i].length;
+
+	return count_trbs(addr, len);
+}
+
+static void check_trb_math(struct urb *urb, int running_total)
+{
+	if (unlikely(running_total != urb->transfer_buffer_length))
+		dev_err(&urb->dev->dev, "%s - ep %#x - Miscalculated tx length, "
+				"queued %#x (%d), asked for %#x (%d)\n",
+				__func__,
+				urb->ep->desc.bEndpointAddress,
+				running_total, running_total,
+				urb->transfer_buffer_length,
+				urb->transfer_buffer_length);
+}
+
+static void giveback_first_trb(struct xhci_hcd *xhci, int slot_id,
+		unsigned int ep_index, unsigned int stream_id, int start_cycle,
+		struct xhci_generic_trb *start_trb)
+{
+	/*
+	 * Pass all the TRBs to the hardware at once and make sure this write
+	 * isn't reordered.
+	 */
+	wmb();
+	if (start_cycle)
+		start_trb->field[3] |= cpu_to_le32(start_cycle);
+	else
+		start_trb->field[3] &= cpu_to_le32(~TRB_CYCLE);
+	xhci_ring_ep_doorbell(xhci, slot_id, ep_index, stream_id);
+}
+
+static void check_interval(struct xhci_hcd *xhci, struct urb *urb,
+						struct xhci_ep_ctx *ep_ctx)
+{
+	int xhci_interval;
+	int ep_interval;
+
+	xhci_interval = EP_INTERVAL_TO_UFRAMES(le32_to_cpu(ep_ctx->ep_info));
+	ep_interval = urb->interval;
+
+	/* Convert to microframes */
+	if (urb->dev->speed == USB_SPEED_LOW ||
+			urb->dev->speed == USB_SPEED_FULL)
+		ep_interval *= 8;
+
+	/* FIXME change this to a warning and a suggestion to use the new API
+	 * to set the polling interval (once the API is added).
+	 */
+	if (xhci_interval != ep_interval) {
+		dev_dbg_ratelimited(&urb->dev->dev,
+				"Driver uses different interval (%d microframe%s) than xHCI (%d microframe%s)\n",
+				ep_interval, ep_interval == 1 ? "" : "s",
+				xhci_interval, xhci_interval == 1 ? "" : "s");
+		urb->interval = xhci_interval;
+		/* Convert back to frames for LS/FS devices */
+		if (urb->dev->speed == USB_SPEED_LOW ||
+				urb->dev->speed == USB_SPEED_FULL)
+			urb->interval /= 8;
+	}
+}
+
+/*
+ * xHCI uses normal TRBs for both bulk and interrupt.  When the interrupt
+ * endpoint is to be serviced, the xHC will consume (at most) one TD.  A TD
+ * (comprised of sg list entries) can take several service intervals to
+ * transmit.
+ */
+int xhci_queue_intr_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
+		struct urb *urb, int slot_id, unsigned int ep_index)
+{
+	struct xhci_ep_ctx *ep_ctx;
+
+	ep_ctx = xhci_get_ep_ctx(xhci, xhci->devs[slot_id]->out_ctx, ep_index);
+	check_interval(xhci, urb, ep_ctx);
+
+	return xhci_queue_bulk_tx(xhci, mem_flags, urb, slot_id, ep_index);
+}
+
+/*
+ * For xHCI 1.0 host controllers, TD size is the number of max packet sized
+ * packets remaining in the TD (*not* including this TRB).
+ *
+ * Total TD packet count = total_packet_count =
+ *     DIV_ROUND_UP(TD size in bytes / wMaxPacketSize)
+ *
+ * Packets transferred up to and including this TRB = packets_transferred =
+ *     rounddown(total bytes transferred including this TRB / wMaxPacketSize)
+ *
+ * TD size = total_packet_count - packets_transferred
+ *
+ * For xHCI 0.96 and older, TD size field should be the remaining bytes
+ * including this TRB, right shifted by 10
+ *
+ * For all hosts it must fit in bits 21:17, so it can't be bigger than 31.
+ * This is taken care of in the TRB_TD_SIZE() macro
+ *
+ * The last TRB in a TD must have the TD size set to zero.
+ */
+static u32 xhci_td_remainder(struct xhci_hcd *xhci, int transferred,
+			      int trb_buff_len, unsigned int td_total_len,
+			      struct urb *urb, bool more_trbs_coming)
+{
+	u32 maxp, total_packet_count;
+
+	/* MTK xHCI 0.96 contains some features from 1.0 */
+	if (xhci->hci_version < 0x100 && !(xhci->quirks & XHCI_MTK_HOST))
+		return ((td_total_len - transferred) >> 10);
+
+	/* One TRB with a zero-length data packet. */
+	if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
+	    trb_buff_len == td_total_len)
+		return 0;
+
+	/* for MTK xHCI 0.96, TD size include this TRB, but not in 1.x */
+	if ((xhci->quirks & XHCI_MTK_HOST) && (xhci->hci_version < 0x100))
+		trb_buff_len = 0;
+
+	maxp = usb_endpoint_maxp(&urb->ep->desc);
+	total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
+
+	/* Queueing functions don't count the current TRB into transferred */
+	return (total_packet_count - ((transferred + trb_buff_len) / maxp));
+}
+
+
+static int xhci_align_td(struct xhci_hcd *xhci, struct urb *urb, u32 enqd_len,
+			 u32 *trb_buff_len, struct xhci_segment *seg)
+{
+	struct device *dev = xhci_to_hcd(xhci)->self.sysdev;
+	unsigned int unalign;
+	unsigned int max_pkt;
+	u32 new_buff_len;
+	size_t len;
+
+	max_pkt = usb_endpoint_maxp(&urb->ep->desc);
+	unalign = (enqd_len + *trb_buff_len) % max_pkt;
+
+	/* we got lucky, last normal TRB data on segment is packet aligned */
+	if (unalign == 0)
+		return 0;
+
+	xhci_dbg(xhci, "Unaligned %d bytes, buff len %d\n",
+		 unalign, *trb_buff_len);
+
+	/* is the last nornal TRB alignable by splitting it */
+	if (*trb_buff_len > unalign) {
+		*trb_buff_len -= unalign;
+		xhci_dbg(xhci, "split align, new buff len %d\n", *trb_buff_len);
+		return 0;
+	}
+
+	/*
+	 * We want enqd_len + trb_buff_len to sum up to a number aligned to
+	 * number which is divisible by the endpoint's wMaxPacketSize. IOW:
+	 * (size of currently enqueued TRBs + remainder) % wMaxPacketSize == 0.
+	 */
+	new_buff_len = max_pkt - (enqd_len % max_pkt);
+
+	if (new_buff_len > (urb->transfer_buffer_length - enqd_len))
+		new_buff_len = (urb->transfer_buffer_length - enqd_len);
+
+	/* create a max max_pkt sized bounce buffer pointed to by last trb */
+	if (usb_urb_dir_out(urb)) {
+		if (urb->num_sgs) {
+			len = sg_pcopy_to_buffer(urb->sg, urb->num_sgs,
+						 seg->bounce_buf, new_buff_len, enqd_len);
+			if (len != new_buff_len)
+				xhci_warn(xhci, "WARN Wrong bounce buffer write length: %zu != %d\n",
+					  len, new_buff_len);
+		} else {
+			memcpy(seg->bounce_buf, urb->transfer_buffer + enqd_len, new_buff_len);
+		}
+
+		seg->bounce_dma = dma_map_single(dev, seg->bounce_buf,
+						 max_pkt, DMA_TO_DEVICE);
+	} else {
+		seg->bounce_dma = dma_map_single(dev, seg->bounce_buf,
+						 max_pkt, DMA_FROM_DEVICE);
+	}
+
+	if (dma_mapping_error(dev, seg->bounce_dma)) {
+		/* try without aligning. Some host controllers survive */
+		xhci_warn(xhci, "Failed mapping bounce buffer, not aligning\n");
+		return 0;
+	}
+	*trb_buff_len = new_buff_len;
+	seg->bounce_len = new_buff_len;
+	seg->bounce_offs = enqd_len;
+
+	xhci_dbg(xhci, "Bounce align, new buff len %d\n", *trb_buff_len);
+
+	return 1;
+}
+
+/* This is very similar to what ehci-q.c qtd_fill() does */
+int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
+		struct urb *urb, int slot_id, unsigned int ep_index)
+{
+	struct xhci_ring *ring;
+	struct urb_priv *urb_priv;
+	struct xhci_td *td;
+	struct xhci_generic_trb *start_trb;
+	struct scatterlist *sg = NULL;
+	bool more_trbs_coming = true;
+	bool need_zero_pkt = false;
+	bool first_trb = true;
+	unsigned int num_trbs;
+	unsigned int start_cycle, num_sgs = 0;
+	unsigned int enqd_len, block_len, trb_buff_len, full_len;
+	int sent_len, ret;
+	u32 field, length_field, remainder;
+	u64 addr, send_addr;
+
+	ring = xhci_urb_to_transfer_ring(xhci, urb);
+	if (!ring)
+		return -EINVAL;
+
+	full_len = urb->transfer_buffer_length;
+	/* If we have scatter/gather list, we use it. */
+	if (urb->num_sgs && !(urb->transfer_flags & URB_DMA_MAP_SINGLE)) {
+		num_sgs = urb->num_mapped_sgs;
+		sg = urb->sg;
+		addr = (u64) sg_dma_address(sg);
+		block_len = sg_dma_len(sg);
+		num_trbs = count_sg_trbs_needed(urb);
+	} else {
+		num_trbs = count_trbs_needed(urb);
+		addr = (u64) urb->transfer_dma;
+		block_len = full_len;
+	}
+	ret = prepare_transfer(xhci, xhci->devs[slot_id],
+			ep_index, urb->stream_id,
+			num_trbs, urb, 0, mem_flags);
+	if (unlikely(ret < 0))
+		return ret;
+
+	urb_priv = urb->hcpriv;
+
+	/* Deal with URB_ZERO_PACKET - need one more td/trb */
+	if (urb->transfer_flags & URB_ZERO_PACKET && urb_priv->num_tds > 1)
+		need_zero_pkt = true;
+
+	td = &urb_priv->td[0];
+
+	/*
+	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
+	 * until we've finished creating all the other TRBs.  The ring's cycle
+	 * state may change as we enqueue the other TRBs, so save it too.
+	 */
+	start_trb = &ring->enqueue->generic;
+	start_cycle = ring->cycle_state;
+	send_addr = addr;
+
+	/* Queue the TRBs, even if they are zero-length */
+	for (enqd_len = 0; first_trb || enqd_len < full_len;
+			enqd_len += trb_buff_len) {
+		field = TRB_TYPE(TRB_NORMAL);
+
+		/* TRB buffer should not cross 64KB boundaries */
+		trb_buff_len = TRB_BUFF_LEN_UP_TO_BOUNDARY(addr);
+		trb_buff_len = min_t(unsigned int, trb_buff_len, block_len);
+
+		if (enqd_len + trb_buff_len > full_len)
+			trb_buff_len = full_len - enqd_len;
+
+		/* Don't change the cycle bit of the first TRB until later */
+		if (first_trb) {
+			first_trb = false;
+			if (start_cycle == 0)
+				field |= TRB_CYCLE;
+		} else
+			field |= ring->cycle_state;
+
+		/* Chain all the TRBs together; clear the chain bit in the last
+		 * TRB to indicate it's the last TRB in the chain.
+		 */
+		if (enqd_len + trb_buff_len < full_len) {
+			field |= TRB_CHAIN;
+			if (trb_is_link(ring->enqueue + 1)) {
+				if (xhci_align_td(xhci, urb, enqd_len,
+						  &trb_buff_len,
+						  ring->enq_seg)) {
+					send_addr = ring->enq_seg->bounce_dma;
+					/* assuming TD won't span 2 segs */
+					td->bounce_seg = ring->enq_seg;
+				}
+			}
+		}
+		if (enqd_len + trb_buff_len >= full_len) {
+			field &= ~TRB_CHAIN;
+			field |= TRB_IOC;
+			more_trbs_coming = false;
+			td->last_trb = ring->enqueue;
+			td->last_trb_seg = ring->enq_seg;
+			if (xhci_urb_suitable_for_idt(urb)) {
+				memcpy(&send_addr, urb->transfer_buffer,
+				       trb_buff_len);
+				le64_to_cpus(&send_addr);
+				field |= TRB_IDT;
+			}
+		}
+
+		/* Only set interrupt on short packet for IN endpoints */
+		if (usb_urb_dir_in(urb))
+			field |= TRB_ISP;
+
+		/* Set the TRB length, TD size, and interrupter fields. */
+		remainder = xhci_td_remainder(xhci, enqd_len, trb_buff_len,
+					      full_len, urb, more_trbs_coming);
+
+		length_field = TRB_LEN(trb_buff_len) |
+			TRB_TD_SIZE(remainder) |
+			TRB_INTR_TARGET(0);
+
+		queue_trb(xhci, ring, more_trbs_coming | need_zero_pkt,
+				lower_32_bits(send_addr),
+				upper_32_bits(send_addr),
+				length_field,
+				field);
+		td->num_trbs++;
+		addr += trb_buff_len;
+		sent_len = trb_buff_len;
+
+		while (sg && sent_len >= block_len) {
+			/* New sg entry */
+			--num_sgs;
+			sent_len -= block_len;
+			sg = sg_next(sg);
+			if (num_sgs != 0 && sg) {
+				block_len = sg_dma_len(sg);
+				addr = (u64) sg_dma_address(sg);
+				addr += sent_len;
+			}
+		}
+		block_len -= sent_len;
+		send_addr = addr;
+	}
+
+	if (need_zero_pkt) {
+		ret = prepare_transfer(xhci, xhci->devs[slot_id],
+				       ep_index, urb->stream_id,
+				       1, urb, 1, mem_flags);
+		urb_priv->td[1].last_trb = ring->enqueue;
+		urb_priv->td[1].last_trb_seg = ring->enq_seg;
+		field = TRB_TYPE(TRB_NORMAL) | ring->cycle_state | TRB_IOC;
+		queue_trb(xhci, ring, 0, 0, 0, TRB_INTR_TARGET(0), field);
+		urb_priv->td[1].num_trbs++;
+	}
+
+	check_trb_math(urb, enqd_len);
+	giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
+			start_cycle, start_trb);
+	return 0;
+}
+
+/* Caller must have locked xhci->lock */
+int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
+		struct urb *urb, int slot_id, unsigned int ep_index)
+{
+	struct xhci_ring *ep_ring;
+	int num_trbs;
+	int ret;
+	struct usb_ctrlrequest *setup;
+	struct xhci_generic_trb *start_trb;
+	int start_cycle;
+	u32 field;
+	struct urb_priv *urb_priv;
+	struct xhci_td *td;
+
+	ep_ring = xhci_urb_to_transfer_ring(xhci, urb);
+	if (!ep_ring)
+		return -EINVAL;
+
+	/*
+	 * Need to copy setup packet into setup TRB, so we can't use the setup
+	 * DMA address.
+	 */
+	if (!urb->setup_packet)
+		return -EINVAL;
+
+	/* 1 TRB for setup, 1 for status */
+	num_trbs = 2;
+	/*
+	 * Don't need to check if we need additional event data and normal TRBs,
+	 * since data in control transfers will never get bigger than 16MB
+	 * XXX: can we get a buffer that crosses 64KB boundaries?
+	 */
+	if (urb->transfer_buffer_length > 0)
+		num_trbs++;
+	ret = prepare_transfer(xhci, xhci->devs[slot_id],
+			ep_index, urb->stream_id,
+			num_trbs, urb, 0, mem_flags);
+	if (ret < 0)
+		return ret;
+
+	urb_priv = urb->hcpriv;
+	td = &urb_priv->td[0];
+	td->num_trbs = num_trbs;
+
+	/*
+	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
+	 * until we've finished creating all the other TRBs.  The ring's cycle
+	 * state may change as we enqueue the other TRBs, so save it too.
+	 */
+	start_trb = &ep_ring->enqueue->generic;
+	start_cycle = ep_ring->cycle_state;
+
+	/* Queue setup TRB - see section 6.4.1.2.1 */
+	/* FIXME better way to translate setup_packet into two u32 fields? */
+	setup = (struct usb_ctrlrequest *) urb->setup_packet;
+	field = 0;
+	field |= TRB_IDT | TRB_TYPE(TRB_SETUP);
+	if (start_cycle == 0)
+		field |= 0x1;
+
+	/* xHCI 1.0/1.1 6.4.1.2.1: Transfer Type field */
+	if ((xhci->hci_version >= 0x100) || (xhci->quirks & XHCI_MTK_HOST)) {
+		if (urb->transfer_buffer_length > 0) {
+			if (setup->bRequestType & USB_DIR_IN)
+				field |= TRB_TX_TYPE(TRB_DATA_IN);
+			else
+				field |= TRB_TX_TYPE(TRB_DATA_OUT);
+		}
+	}
+
+	queue_trb(xhci, ep_ring, true,
+		  setup->bRequestType | setup->bRequest << 8 | le16_to_cpu(setup->wValue) << 16,
+		  le16_to_cpu(setup->wIndex) | le16_to_cpu(setup->wLength) << 16,
+		  TRB_LEN(8) | TRB_INTR_TARGET(0),
+		  /* Immediate data in pointer */
+		  field);
+
+	/* If there's data, queue data TRBs */
+	/* Only set interrupt on short packet for IN endpoints */
+	if (usb_urb_dir_in(urb))
+		field = TRB_ISP | TRB_TYPE(TRB_DATA);
+	else
+		field = TRB_TYPE(TRB_DATA);
+
+	if (urb->transfer_buffer_length > 0) {
+		u32 length_field, remainder;
+		u64 addr;
+
+		if (xhci_urb_suitable_for_idt(urb)) {
+			memcpy(&addr, urb->transfer_buffer,
+			       urb->transfer_buffer_length);
+			le64_to_cpus(&addr);
+			field |= TRB_IDT;
+		} else {
+			addr = (u64) urb->transfer_dma;
+		}
+
+		remainder = xhci_td_remainder(xhci, 0,
+				urb->transfer_buffer_length,
+				urb->transfer_buffer_length,
+				urb, 1);
+		length_field = TRB_LEN(urb->transfer_buffer_length) |
+				TRB_TD_SIZE(remainder) |
+				TRB_INTR_TARGET(0);
+		if (setup->bRequestType & USB_DIR_IN)
+			field |= TRB_DIR_IN;
+		queue_trb(xhci, ep_ring, true,
+				lower_32_bits(addr),
+				upper_32_bits(addr),
+				length_field,
+				field | ep_ring->cycle_state);
+	}
+
+	/* Save the DMA address of the last TRB in the TD */
+	td->last_trb = ep_ring->enqueue;
+	td->last_trb_seg = ep_ring->enq_seg;
+
+	/* Queue status TRB - see Table 7 and sections 4.11.2.2 and 6.4.1.2.3 */
+	/* If the device sent data, the status stage is an OUT transfer */
+	if (urb->transfer_buffer_length > 0 && setup->bRequestType & USB_DIR_IN)
+		field = 0;
+	else
+		field = TRB_DIR_IN;
+	queue_trb(xhci, ep_ring, false,
+			0,
+			0,
+			TRB_INTR_TARGET(0),
+			/* Event on completion */
+			field | TRB_IOC | TRB_TYPE(TRB_STATUS) | ep_ring->cycle_state);
+
+	giveback_first_trb(xhci, slot_id, ep_index, 0,
+			start_cycle, start_trb);
+	return 0;
+}
+
+/*
+ * The transfer burst count field of the isochronous TRB defines the number of
+ * bursts that are required to move all packets in this TD.  Only SuperSpeed
+ * devices can burst up to bMaxBurst number of packets per service interval.
+ * This field is zero based, meaning a value of zero in the field means one
+ * burst.  Basically, for everything but SuperSpeed devices, this field will be
+ * zero.  Only xHCI 1.0 host controllers support this field.
+ */
+static unsigned int xhci_get_burst_count(struct xhci_hcd *xhci,
+		struct urb *urb, unsigned int total_packet_count)
+{
+	unsigned int max_burst;
+
+	if (xhci->hci_version < 0x100 || urb->dev->speed < USB_SPEED_SUPER)
+		return 0;
+
+	max_burst = urb->ep->ss_ep_comp.bMaxBurst;
+	return DIV_ROUND_UP(total_packet_count, max_burst + 1) - 1;
+}
+
+/*
+ * Returns the number of packets in the last "burst" of packets.  This field is
+ * valid for all speeds of devices.  USB 2.0 devices can only do one "burst", so
+ * the last burst packet count is equal to the total number of packets in the
+ * TD.  SuperSpeed endpoints can have up to 3 bursts.  All but the last burst
+ * must contain (bMaxBurst + 1) number of packets, but the last burst can
+ * contain 1 to (bMaxBurst + 1) packets.
+ */
+static unsigned int xhci_get_last_burst_packet_count(struct xhci_hcd *xhci,
+		struct urb *urb, unsigned int total_packet_count)
+{
+	unsigned int max_burst;
+	unsigned int residue;
+
+	if (xhci->hci_version < 0x100)
+		return 0;
+
+	if (urb->dev->speed >= USB_SPEED_SUPER) {
+		/* bMaxBurst is zero based: 0 means 1 packet per burst */
+		max_burst = urb->ep->ss_ep_comp.bMaxBurst;
+		residue = total_packet_count % (max_burst + 1);
+		/* If residue is zero, the last burst contains (max_burst + 1)
+		 * number of packets, but the TLBPC field is zero-based.
+		 */
+		if (residue == 0)
+			return max_burst;
+		return residue - 1;
+	}
+	if (total_packet_count == 0)
+		return 0;
+	return total_packet_count - 1;
+}
+
+/*
+ * Calculates Frame ID field of the isochronous TRB identifies the
+ * target frame that the Interval associated with this Isochronous
+ * Transfer Descriptor will start on. Refer to 4.11.2.5 in 1.1 spec.
+ *
+ * Returns actual frame id on success, negative value on error.
+ */
+static int xhci_get_isoc_frame_id(struct xhci_hcd *xhci,
+		struct urb *urb, int index)
+{
+	int start_frame, ist, ret = 0;
+	int start_frame_id, end_frame_id, current_frame_id;
+
+	if (urb->dev->speed == USB_SPEED_LOW ||
+			urb->dev->speed == USB_SPEED_FULL)
+		start_frame = urb->start_frame + index * urb->interval;
+	else
+		start_frame = (urb->start_frame + index * urb->interval) >> 3;
+
+	/* Isochronous Scheduling Threshold (IST, bits 0~3 in HCSPARAMS2):
+	 *
+	 * If bit [3] of IST is cleared to '0', software can add a TRB no
+	 * later than IST[2:0] Microframes before that TRB is scheduled to
+	 * be executed.
+	 * If bit [3] of IST is set to '1', software can add a TRB no later
+	 * than IST[2:0] Frames before that TRB is scheduled to be executed.
+	 */
+	ist = HCS_IST(xhci->hcs_params2) & 0x7;
+	if (HCS_IST(xhci->hcs_params2) & (1 << 3))
+		ist <<= 3;
+
+	/* Software shall not schedule an Isoch TD with a Frame ID value that
+	 * is less than the Start Frame ID or greater than the End Frame ID,
+	 * where:
+	 *
+	 * End Frame ID = (Current MFINDEX register value + 895 ms.) MOD 2048
+	 * Start Frame ID = (Current MFINDEX register value + IST + 1) MOD 2048
+	 *
+	 * Both the End Frame ID and Start Frame ID values are calculated
+	 * in microframes. When software determines the valid Frame ID value;
+	 * The End Frame ID value should be rounded down to the nearest Frame
+	 * boundary, and the Start Frame ID value should be rounded up to the
+	 * nearest Frame boundary.
+	 */
+	current_frame_id = readl(&xhci->run_regs->microframe_index);
+	start_frame_id = roundup(current_frame_id + ist + 1, 8);
+	end_frame_id = rounddown(current_frame_id + 895 * 8, 8);
+
+	start_frame &= 0x7ff;
+	start_frame_id = (start_frame_id >> 3) & 0x7ff;
+	end_frame_id = (end_frame_id >> 3) & 0x7ff;
+
+	xhci_dbg(xhci, "%s: index %d, reg 0x%x start_frame_id 0x%x, end_frame_id 0x%x, start_frame 0x%x\n",
+		 __func__, index, readl(&xhci->run_regs->microframe_index),
+		 start_frame_id, end_frame_id, start_frame);
+
+	if (start_frame_id < end_frame_id) {
+		if (start_frame > end_frame_id ||
+				start_frame < start_frame_id)
+			ret = -EINVAL;
+	} else if (start_frame_id > end_frame_id) {
+		if ((start_frame > end_frame_id &&
+				start_frame < start_frame_id))
+			ret = -EINVAL;
+	} else {
+			ret = -EINVAL;
+	}
+
+	if (index == 0) {
+		if (ret == -EINVAL || start_frame == start_frame_id) {
+			start_frame = start_frame_id + 1;
+			if (urb->dev->speed == USB_SPEED_LOW ||
+					urb->dev->speed == USB_SPEED_FULL)
+				urb->start_frame = start_frame;
+			else
+				urb->start_frame = start_frame << 3;
+			ret = 0;
+		}
+	}
+
+	if (ret) {
+		xhci_warn(xhci, "Frame ID %d (reg %d, index %d) beyond range (%d, %d)\n",
+				start_frame, current_frame_id, index,
+				start_frame_id, end_frame_id);
+		xhci_warn(xhci, "Ignore frame ID field, use SIA bit instead\n");
+		return ret;
+	}
+
+	return start_frame;
+}
+
+/* Check if we should generate event interrupt for a TD in an isoc URB */
+static bool trb_block_event_intr(struct xhci_hcd *xhci, int num_tds, int i)
+{
+	if (xhci->hci_version < 0x100)
+		return false;
+	/* always generate an event interrupt for the last TD */
+	if (i == num_tds - 1)
+		return false;
+	/*
+	 * If AVOID_BEI is set the host handles full event rings poorly,
+	 * generate an event at least every 8th TD to clear the event ring
+	 */
+	if (i && xhci->quirks & XHCI_AVOID_BEI)
+		return !!(i % xhci->isoc_bei_interval);
+
+	return true;
+}
+
+/* This is for isoc transfer */
+static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
+		struct urb *urb, int slot_id, unsigned int ep_index)
+{
+	struct xhci_ring *ep_ring;
+	struct urb_priv *urb_priv;
+	struct xhci_td *td;
+	int num_tds, trbs_per_td;
+	struct xhci_generic_trb *start_trb;
+	bool first_trb;
+	int start_cycle;
+	u32 field, length_field;
+	int running_total, trb_buff_len, td_len, td_remain_len, ret;
+	u64 start_addr, addr;
+	int i, j;
+	bool more_trbs_coming;
+	struct xhci_virt_ep *xep;
+	int frame_id;
+
+	xep = &xhci->devs[slot_id]->eps[ep_index];
+	ep_ring = xhci->devs[slot_id]->eps[ep_index].ring;
+
+	num_tds = urb->number_of_packets;
+	if (num_tds < 1) {
+		xhci_dbg(xhci, "Isoc URB with zero packets?\n");
+		return -EINVAL;
+	}
+	start_addr = (u64) urb->transfer_dma;
+	start_trb = &ep_ring->enqueue->generic;
+	start_cycle = ep_ring->cycle_state;
+
+	urb_priv = urb->hcpriv;
+	/* Queue the TRBs for each TD, even if they are zero-length */
+	for (i = 0; i < num_tds; i++) {
+		unsigned int total_pkt_count, max_pkt;
+		unsigned int burst_count, last_burst_pkt_count;
+		u32 sia_frame_id;
+
+		first_trb = true;
+		running_total = 0;
+		addr = start_addr + urb->iso_frame_desc[i].offset;
+		td_len = urb->iso_frame_desc[i].length;
+		td_remain_len = td_len;
+		max_pkt = usb_endpoint_maxp(&urb->ep->desc);
+		total_pkt_count = DIV_ROUND_UP(td_len, max_pkt);
+
+		/* A zero-length transfer still involves at least one packet. */
+		if (total_pkt_count == 0)
+			total_pkt_count++;
+		burst_count = xhci_get_burst_count(xhci, urb, total_pkt_count);
+		last_burst_pkt_count = xhci_get_last_burst_packet_count(xhci,
+							urb, total_pkt_count);
+
+		trbs_per_td = count_isoc_trbs_needed(urb, i);
+
+		ret = prepare_transfer(xhci, xhci->devs[slot_id], ep_index,
+				urb->stream_id, trbs_per_td, urb, i, mem_flags);
+		if (ret < 0) {
+			if (i == 0)
+				return ret;
+			goto cleanup;
+		}
+		td = &urb_priv->td[i];
+		td->num_trbs = trbs_per_td;
+		/* use SIA as default, if frame id is used overwrite it */
+		sia_frame_id = TRB_SIA;
+		if (!(urb->transfer_flags & URB_ISO_ASAP) &&
+		    HCC_CFC(xhci->hcc_params)) {
+			frame_id = xhci_get_isoc_frame_id(xhci, urb, i);
+			if (frame_id >= 0)
+				sia_frame_id = TRB_FRAME_ID(frame_id);
+		}
+		/*
+		 * Set isoc specific data for the first TRB in a TD.
+		 * Prevent HW from getting the TRBs by keeping the cycle state
+		 * inverted in the first TDs isoc TRB.
+		 */
+		field = TRB_TYPE(TRB_ISOC) |
+			TRB_TLBPC(last_burst_pkt_count) |
+			sia_frame_id |
+			(i ? ep_ring->cycle_state : !start_cycle);
+
+		/* xhci 1.1 with ETE uses TD_Size field for TBC, old is Rsvdz */
+		if (!xep->use_extended_tbc)
+			field |= TRB_TBC(burst_count);
+
+		/* fill the rest of the TRB fields, and remaining normal TRBs */
+		for (j = 0; j < trbs_per_td; j++) {
+			u32 remainder = 0;
+
+			/* only first TRB is isoc, overwrite otherwise */
+			if (!first_trb)
+				field = TRB_TYPE(TRB_NORMAL) |
+					ep_ring->cycle_state;
+
+			/* Only set interrupt on short packet for IN EPs */
+			if (usb_urb_dir_in(urb))
+				field |= TRB_ISP;
+
+			/* Set the chain bit for all except the last TRB  */
+			if (j < trbs_per_td - 1) {
+				more_trbs_coming = true;
+				field |= TRB_CHAIN;
+			} else {
+				more_trbs_coming = false;
+				td->last_trb = ep_ring->enqueue;
+				td->last_trb_seg = ep_ring->enq_seg;
+				field |= TRB_IOC;
+				if (trb_block_event_intr(xhci, num_tds, i))
+					field |= TRB_BEI;
+			}
+			/* Calculate TRB length */
+			trb_buff_len = TRB_BUFF_LEN_UP_TO_BOUNDARY(addr);
+			if (trb_buff_len > td_remain_len)
+				trb_buff_len = td_remain_len;
+
+			/* Set the TRB length, TD size, & interrupter fields. */
+			remainder = xhci_td_remainder(xhci, running_total,
+						   trb_buff_len, td_len,
+						   urb, more_trbs_coming);
+
+			length_field = TRB_LEN(trb_buff_len) |
+				TRB_INTR_TARGET(0);
+
+			/* xhci 1.1 with ETE uses TD Size field for TBC */
+			if (first_trb && xep->use_extended_tbc)
+				length_field |= TRB_TD_SIZE_TBC(burst_count);
+			else
+				length_field |= TRB_TD_SIZE(remainder);
+			first_trb = false;
+
+			queue_trb(xhci, ep_ring, more_trbs_coming,
+				lower_32_bits(addr),
+				upper_32_bits(addr),
+				length_field,
+				field);
+			running_total += trb_buff_len;
+
+			addr += trb_buff_len;
+			td_remain_len -= trb_buff_len;
+		}
+
+		/* Check TD length */
+		if (running_total != td_len) {
+			xhci_err(xhci, "ISOC TD length unmatch\n");
+			ret = -EINVAL;
+			goto cleanup;
+		}
+	}
+
+	/* store the next frame id */
+	if (HCC_CFC(xhci->hcc_params))
+		xep->next_frame_id = urb->start_frame + num_tds * urb->interval;
+
+	if (xhci_to_hcd(xhci)->self.bandwidth_isoc_reqs == 0) {
+		if (xhci->quirks & XHCI_AMD_PLL_FIX)
+			usb_amd_quirk_pll_disable();
+	}
+	xhci_to_hcd(xhci)->self.bandwidth_isoc_reqs++;
+
+	giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
+			start_cycle, start_trb);
+	return 0;
+cleanup:
+	/* Clean up a partially enqueued isoc transfer. */
+
+	for (i--; i >= 0; i--)
+		list_del_init(&urb_priv->td[i].td_list);
+
+	/* Use the first TD as a temporary variable to turn the TDs we've queued
+	 * into No-ops with a software-owned cycle bit. That way the hardware
+	 * won't accidentally start executing bogus TDs when we partially
+	 * overwrite them.  td->first_trb and td->start_seg are already set.
+	 */
+	urb_priv->td[0].last_trb = ep_ring->enqueue;
+	/* Every TRB except the first & last will have its cycle bit flipped. */
+	td_to_noop(xhci, ep_ring, &urb_priv->td[0], true);
+
+	/* Reset the ring enqueue back to the first TRB and its cycle bit. */
+	ep_ring->enqueue = urb_priv->td[0].first_trb;
+	ep_ring->enq_seg = urb_priv->td[0].start_seg;
+	ep_ring->cycle_state = start_cycle;
+	ep_ring->num_trbs_free = ep_ring->num_trbs_free_temp;
+	usb_hcd_unlink_urb_from_ep(bus_to_hcd(urb->dev->bus), urb);
+	return ret;
+}
+
+/*
+ * Check transfer ring to guarantee there is enough room for the urb.
+ * Update ISO URB start_frame and interval.
+ * Update interval as xhci_queue_intr_tx does. Use xhci frame_index to
+ * update urb->start_frame if URB_ISO_ASAP is set in transfer_flags or
+ * Contiguous Frame ID is not supported by HC.
+ */
+int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci, gfp_t mem_flags,
+		struct urb *urb, int slot_id, unsigned int ep_index)
+{
+	struct xhci_virt_device *xdev;
+	struct xhci_ring *ep_ring;
+	struct xhci_ep_ctx *ep_ctx;
+	int start_frame;
+	int num_tds, num_trbs, i;
+	int ret;
+	struct xhci_virt_ep *xep;
+	int ist;
+
+	xdev = xhci->devs[slot_id];
+	xep = &xhci->devs[slot_id]->eps[ep_index];
+	ep_ring = xdev->eps[ep_index].ring;
+	ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
+
+	num_trbs = 0;
+	num_tds = urb->number_of_packets;
+	for (i = 0; i < num_tds; i++)
+		num_trbs += count_isoc_trbs_needed(urb, i);
+
+	/* Check the ring to guarantee there is enough room for the whole urb.
+	 * Do not insert any td of the urb to the ring if the check failed.
+	 */
+	ret = prepare_ring(xhci, ep_ring, GET_EP_CTX_STATE(ep_ctx),
+			   num_trbs, mem_flags);
+	if (ret)
+		return ret;
+
+	/*
+	 * Check interval value. This should be done before we start to
+	 * calculate the start frame value.
+	 */
+	check_interval(xhci, urb, ep_ctx);
+
+	/* Calculate the start frame and put it in urb->start_frame. */
+	if (HCC_CFC(xhci->hcc_params) && !list_empty(&ep_ring->td_list)) {
+		if (GET_EP_CTX_STATE(ep_ctx) ==	EP_STATE_RUNNING) {
+			urb->start_frame = xep->next_frame_id;
+			goto skip_start_over;
+		}
+	}
+
+	start_frame = readl(&xhci->run_regs->microframe_index);
+	start_frame &= 0x3fff;
+	/*
+	 * Round up to the next frame and consider the time before trb really
+	 * gets scheduled by hardare.
+	 */
+	ist = HCS_IST(xhci->hcs_params2) & 0x7;
+	if (HCS_IST(xhci->hcs_params2) & (1 << 3))
+		ist <<= 3;
+	start_frame += ist + XHCI_CFC_DELAY;
+	start_frame = roundup(start_frame, 8);
+
+	/*
+	 * Round up to the next ESIT (Endpoint Service Interval Time) if ESIT
+	 * is greate than 8 microframes.
+	 */
+	if (urb->dev->speed == USB_SPEED_LOW ||
+			urb->dev->speed == USB_SPEED_FULL) {
+		start_frame = roundup(start_frame, urb->interval << 3);
+		urb->start_frame = start_frame >> 3;
+	} else {
+		start_frame = roundup(start_frame, urb->interval);
+		urb->start_frame = start_frame;
+	}
+
+skip_start_over:
+	ep_ring->num_trbs_free_temp = ep_ring->num_trbs_free;
+
+	return xhci_queue_isoc_tx(xhci, mem_flags, urb, slot_id, ep_index);
+}
+
+/****		Command Ring Operations		****/
+
+/* Generic function for queueing a command TRB on the command ring.
+ * Check to make sure there's room on the command ring for one command TRB.
+ * Also check that there's room reserved for commands that must not fail.
+ * If this is a command that must not fail, meaning command_must_succeed = TRUE,
+ * then only check for the number of reserved spots.
+ * Don't decrement xhci->cmd_ring_reserved_trbs after we've queued the TRB
+ * because the command event handler may want to resubmit a failed command.
+ */
+static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd,
+			 u32 field1, u32 field2,
+			 u32 field3, u32 field4, bool command_must_succeed)
+{
+	int reserved_trbs = xhci->cmd_ring_reserved_trbs;
+	int ret;
+
+	if ((xhci->xhc_state & XHCI_STATE_DYING) ||
+		(xhci->xhc_state & XHCI_STATE_HALTED)) {
+		xhci_dbg(xhci, "xHCI dying or halted, can't queue_command\n");
+		return -ESHUTDOWN;
+	}
+
+	if (!command_must_succeed)
+		reserved_trbs++;
+
+	ret = prepare_ring(xhci, xhci->cmd_ring, EP_STATE_RUNNING,
+			reserved_trbs, GFP_ATOMIC);
+	if (ret < 0) {
+		xhci_err(xhci, "ERR: No room for command on command ring\n");
+		if (command_must_succeed)
+			xhci_err(xhci, "ERR: Reserved TRB counting for "
+					"unfailable commands failed.\n");
+		return ret;
+	}
+
+	cmd->command_trb = xhci->cmd_ring->enqueue;
+
+	/* if there are no other commands queued we start the timeout timer */
+	if (list_empty(&xhci->cmd_list)) {
+		xhci->current_cmd = cmd;
+		xhci_mod_cmd_timer(xhci, XHCI_CMD_DEFAULT_TIMEOUT);
+	}
+
+	list_add_tail(&cmd->cmd_list, &xhci->cmd_list);
+
+	queue_trb(xhci, xhci->cmd_ring, false, field1, field2, field3,
+			field4 | xhci->cmd_ring->cycle_state);
+	return 0;
+}
+
+/* Queue a slot enable or disable request on the command ring */
+int xhci_queue_slot_control(struct xhci_hcd *xhci, struct xhci_command *cmd,
+		u32 trb_type, u32 slot_id)
+{
+	return queue_command(xhci, cmd, 0, 0, 0,
+			TRB_TYPE(trb_type) | SLOT_ID_FOR_TRB(slot_id), false);
+}
+
+/* Queue an address device command TRB */
+int xhci_queue_address_device(struct xhci_hcd *xhci, struct xhci_command *cmd,
+		dma_addr_t in_ctx_ptr, u32 slot_id, enum xhci_setup_dev setup)
+{
+	return queue_command(xhci, cmd, lower_32_bits(in_ctx_ptr),
+			upper_32_bits(in_ctx_ptr), 0,
+			TRB_TYPE(TRB_ADDR_DEV) | SLOT_ID_FOR_TRB(slot_id)
+			| (setup == SETUP_CONTEXT_ONLY ? TRB_BSR : 0), false);
+}
+
+int xhci_queue_vendor_command(struct xhci_hcd *xhci, struct xhci_command *cmd,
+		u32 field1, u32 field2, u32 field3, u32 field4)
+{
+	return queue_command(xhci, cmd, field1, field2, field3, field4, false);
+}
+
+/* Queue a reset device command TRB */
+int xhci_queue_reset_device(struct xhci_hcd *xhci, struct xhci_command *cmd,
+		u32 slot_id)
+{
+	return queue_command(xhci, cmd, 0, 0, 0,
+			TRB_TYPE(TRB_RESET_DEV) | SLOT_ID_FOR_TRB(slot_id),
+			false);
+}
+
+/* Queue a configure endpoint command TRB */
+int xhci_queue_configure_endpoint(struct xhci_hcd *xhci,
+		struct xhci_command *cmd, dma_addr_t in_ctx_ptr,
+		u32 slot_id, bool command_must_succeed)
+{
+	return queue_command(xhci, cmd, lower_32_bits(in_ctx_ptr),
+			upper_32_bits(in_ctx_ptr), 0,
+			TRB_TYPE(TRB_CONFIG_EP) | SLOT_ID_FOR_TRB(slot_id),
+			command_must_succeed);
+}
+
+/* Queue an evaluate context command TRB */
+int xhci_queue_evaluate_context(struct xhci_hcd *xhci, struct xhci_command *cmd,
+		dma_addr_t in_ctx_ptr, u32 slot_id, bool command_must_succeed)
+{
+	return queue_command(xhci, cmd, lower_32_bits(in_ctx_ptr),
+			upper_32_bits(in_ctx_ptr), 0,
+			TRB_TYPE(TRB_EVAL_CONTEXT) | SLOT_ID_FOR_TRB(slot_id),
+			command_must_succeed);
+}
+
+/*
+ * Suspend is set to indicate "Stop Endpoint Command" is being issued to stop
+ * activity on an endpoint that is about to be suspended.
+ */
+int xhci_queue_stop_endpoint(struct xhci_hcd *xhci, struct xhci_command *cmd,
+			     int slot_id, unsigned int ep_index, int suspend)
+{
+	u32 trb_slot_id = SLOT_ID_FOR_TRB(slot_id);
+	u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
+	u32 type = TRB_TYPE(TRB_STOP_RING);
+	u32 trb_suspend = SUSPEND_PORT_FOR_TRB(suspend);
+
+	return queue_command(xhci, cmd, 0, 0, 0,
+			trb_slot_id | trb_ep_index | type | trb_suspend, false);
+}
+
+int xhci_queue_reset_ep(struct xhci_hcd *xhci, struct xhci_command *cmd,
+			int slot_id, unsigned int ep_index,
+			enum xhci_ep_reset_type reset_type)
+{
+	u32 trb_slot_id = SLOT_ID_FOR_TRB(slot_id);
+	u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
+	u32 type = TRB_TYPE(TRB_RESET_EP);
+
+	if (reset_type == EP_SOFT_RESET)
+		type |= TRB_TSP;
+
+	return queue_command(xhci, cmd, 0, 0, 0,
+			trb_slot_id | trb_ep_index | type, false);
+}