/*
   * xHCI host controller driver
   *
   * Copyright (C) 2008 Intel Corp.
   *
   * Author: Sarah Sharp
   * Some code borrowed from the Linux EHCI driver.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software Foundation,
   * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #include <linux/usb.h>
  #include <linux/pci.h>
  #include <linux/slab.h>
  #include <linux/dmapool.h>
  #include <linux/dma-mapping.h>
  
  #include "xhci.h"
  #include "xhci-trace.h"
  
  /*
   * Allocates a generic ring segment from the ring pool, sets the dma address,
   * initializes the segment to zero, and sets the private next pointer to NULL.
   *
   * Section 4.11.1.1:
   * "All components of all Command and Transfer TRBs shall be initialized to '0'"
   */
  static struct xhci_segment *xhci_segment_alloc(struct xhci_hcd *xhci,
  					unsigned int cycle_state, gfp_t flags)
  {
  	struct xhci_segment *seg;
  	dma_addr_t	dma;
  	int		i;
  
  	seg = kzalloc(sizeof *seg, flags);
  	if (!seg)
  		return NULL;
  
  	seg->trbs = dma_pool_alloc(xhci->segment_pool, flags, &dma);
  	if (!seg->trbs) {
  		kfree(seg);
  		return NULL;
  	}
  
  	memset(seg->trbs, 0, TRB_SEGMENT_SIZE);
  	/* If the cycle state is 0, set the cycle bit to 1 for all the TRBs */
  	if (cycle_state == 0) {
  		for (i = 0; i < TRBS_PER_SEGMENT; i++)
  			seg->trbs[i].link.control |= cpu_to_le32(TRB_CYCLE);
  	}
  	seg->dma = dma;
  	seg->next = NULL;
  
  	return seg;
  }
  
  static void xhci_segment_free(struct xhci_hcd *xhci, struct xhci_segment *seg)
  {
  	if (seg->trbs) {
  		dma_pool_free(xhci->segment_pool, seg->trbs, seg->dma);
  		seg->trbs = NULL;
  	}
  	kfree(seg);
  }
  
  static void xhci_free_segments_for_ring(struct xhci_hcd *xhci,
  				struct xhci_segment *first)
  {
  	struct xhci_segment *seg;
  
  	seg = first->next;
  	while (seg != first) {
  		struct xhci_segment *next = seg->next;
  		xhci_segment_free(xhci, seg);
  		seg = next;
  	}
  	xhci_segment_free(xhci, first);
  }
  
  /*
   * Make the prev segment point to the next segment.
   *
   * Change the last TRB in the prev segment to be a Link TRB which points to the
   * DMA address of the next segment.  The caller needs to set any Link TRB
   * related flags, such as End TRB, Toggle Cycle, and no snoop.
   */
  static void xhci_link_segments(struct xhci_hcd *xhci, struct xhci_segment *prev,
  		struct xhci_segment *next, enum xhci_ring_type type)
  {
  	u32 val;
  
  	if (!prev || !next)
  		return;
  	prev->next = next;
  	if (type != TYPE_EVENT) {
  		prev->trbs[TRBS_PER_SEGMENT-1].link.segment_ptr =
  			cpu_to_le64(next->dma);
  
  		/* Set the last TRB in the segment to have a TRB type ID of Link TRB */
  		val = le32_to_cpu(prev->trbs[TRBS_PER_SEGMENT-1].link.control);
  		val &= ~TRB_TYPE_BITMASK;
  		val |= TRB_TYPE(TRB_LINK);
  		/* Always set the chain bit with 0.95 hardware */
  		/* Set chain bit for isoc rings on AMD 0.96 host */
  		if (xhci_link_trb_quirk(xhci) ||
  				(type == TYPE_ISOC &&
  				 (xhci->quirks & XHCI_AMD_0x96_HOST)))
  			val |= TRB_CHAIN;
  		prev->trbs[TRBS_PER_SEGMENT-1].link.control = cpu_to_le32(val);
  	}
  }
  
  /*
   * Link the ring to the new segments.
   * Set Toggle Cycle for the new ring if needed.
   */
  static void xhci_link_rings(struct xhci_hcd *xhci, struct xhci_ring *ring,
  		struct xhci_segment *first, struct xhci_segment *last,
  		unsigned int num_segs)
  {
  	struct xhci_segment *next;
  
  	if (!ring || !first || !last)
  		return;
  
  	next = ring->enq_seg->next;
  	xhci_link_segments(xhci, ring->enq_seg, first, ring->type);
  	xhci_link_segments(xhci, last, next, ring->type);
  	ring->num_segs += num_segs;
  	ring->num_trbs_free += (TRBS_PER_SEGMENT - 1) * num_segs;
  
  	if (ring->type != TYPE_EVENT && ring->enq_seg == ring->last_seg) {
  		ring->last_seg->trbs[TRBS_PER_SEGMENT-1].link.control
  			&= ~cpu_to_le32(LINK_TOGGLE);
  		last->trbs[TRBS_PER_SEGMENT-1].link.control
  			|= cpu_to_le32(LINK_TOGGLE);
  		ring->last_seg = last;
  	}
  }
  
  /* XXX: Do we need the hcd structure in all these functions? */
  void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring)
  {
  	if (!ring)
  		return;
  
  	if (ring->first_seg)
  		xhci_free_segments_for_ring(xhci, ring->first_seg);
  
  	kfree(ring);
  }
  
  static void xhci_initialize_ring_info(struct xhci_ring *ring,
  					unsigned int cycle_state)
  {
  	/* The ring is empty, so the enqueue pointer == dequeue pointer */
  	ring->enqueue = ring->first_seg->trbs;
  	ring->enq_seg = ring->first_seg;
  	ring->dequeue = ring->enqueue;
  	ring->deq_seg = ring->first_seg;
  	/* The ring is initialized to 0. The producer must write 1 to the cycle
  	 * bit to handover ownership of the TRB, so PCS = 1.  The consumer must
  	 * compare CCS to the cycle bit to check ownership, so CCS = 1.
  	 *
  	 * New rings are initialized with cycle state equal to 1; if we are
  	 * handling ring expansion, set the cycle state equal to the old ring.
  	 */
  	ring->cycle_state = cycle_state;
  	/* Not necessary for new rings, but needed for re-initialized rings */
  	ring->enq_updates = 0;
  	ring->deq_updates = 0;
  
  	/*
  	 * Each segment has a link TRB, and leave an extra TRB for SW
  	 * accounting purpose
  	 */
  	ring->num_trbs_free = ring->num_segs * (TRBS_PER_SEGMENT - 1) - 1;
  }
  
  /* Allocate segments and link them for a ring */
  static int xhci_alloc_segments_for_ring(struct xhci_hcd *xhci,
  		struct xhci_segment **first, struct xhci_segment **last,
  		unsigned int num_segs, unsigned int cycle_state,
  		enum xhci_ring_type type, gfp_t flags)
  {
  	struct xhci_segment *prev;
  
  	prev = xhci_segment_alloc(xhci, cycle_state, flags);
  	if (!prev)
  		return -ENOMEM;
  	num_segs--;
  
  	*first = prev;
  	while (num_segs > 0) {
  		struct xhci_segment	*next;
  
  		next = xhci_segment_alloc(xhci, cycle_state, flags);
  		if (!next) {
  			prev = *first;
  			while (prev) {
  				next = prev->next;
  				xhci_segment_free(xhci, prev);
  				prev = next;
  			}
  			return -ENOMEM;
  		}
  		xhci_link_segments(xhci, prev, next, type);
  
  		prev = next;
  		num_segs--;
  	}
  	xhci_link_segments(xhci, prev, *first, type);
  	*last = prev;
  
  	return 0;
  }
  
  /**
   * Create a new ring with zero or more segments.
   *
   * Link each segment together into a ring.
   * Set the end flag and the cycle toggle bit on the last segment.
   * See section 4.9.1 and figures 15 and 16.
   */
  static struct xhci_ring *xhci_ring_alloc(struct xhci_hcd *xhci,
  		unsigned int num_segs, unsigned int cycle_state,
  		enum xhci_ring_type type, gfp_t flags)
  {
  	struct xhci_ring	*ring;
  	int ret;
  
  	ring = kzalloc(sizeof *(ring), flags);
  	if (!ring)
  		return NULL;
  
  	ring->num_segs = num_segs;
  	INIT_LIST_HEAD(&ring->td_list);
  	ring->type = type;
  	if (num_segs == 0)
  		return ring;
  
  	ret = xhci_alloc_segments_for_ring(xhci, &ring->first_seg,
  			&ring->last_seg, num_segs, cycle_state, type, flags);
  	if (ret)
  		goto fail;
  
  	/* Only event ring does not use link TRB */
  	if (type != TYPE_EVENT) {
  		/* See section 4.9.2.1 and 6.4.4.1 */
  		ring->last_seg->trbs[TRBS_PER_SEGMENT - 1].link.control |=
  			cpu_to_le32(LINK_TOGGLE);
  	}
  	xhci_initialize_ring_info(ring, cycle_state);
  	return ring;
  
  fail:
  	kfree(ring);
  	return NULL;
  }
  
  void xhci_free_or_cache_endpoint_ring(struct xhci_hcd *xhci,
  		struct xhci_virt_device *virt_dev,
  		unsigned int ep_index)
  {
  	int rings_cached;
  
  	rings_cached = virt_dev->num_rings_cached;
  	if (rings_cached < XHCI_MAX_RINGS_CACHED) {
  		virt_dev->ring_cache[rings_cached] =
  			virt_dev->eps[ep_index].ring;
  		virt_dev->num_rings_cached++;
  		xhci_dbg(xhci, "Cached old ring, "
  				"%d ring%s cached
  ",
  				virt_dev->num_rings_cached,
  				(virt_dev->num_rings_cached > 1) ? "s" : "");
  	} else {
  		xhci_ring_free(xhci, virt_dev->eps[ep_index].ring);
  		xhci_dbg(xhci, "Ring cache full (%d rings), "
  				"freeing ring
  ",
  				virt_dev->num_rings_cached);
  	}
  	virt_dev->eps[ep_index].ring = NULL;
  }
  
  /* Zero an endpoint ring (except for link TRBs) and move the enqueue and dequeue
   * pointers to the beginning of the ring.
   */
  static void xhci_reinit_cached_ring(struct xhci_hcd *xhci,
  			struct xhci_ring *ring, unsigned int cycle_state,
  			enum xhci_ring_type type)
  {
  	struct xhci_segment	*seg = ring->first_seg;
  	int i;
  
  	do {
  		memset(seg->trbs, 0,
  				sizeof(union xhci_trb)*TRBS_PER_SEGMENT);
  		if (cycle_state == 0) {
  			for (i = 0; i < TRBS_PER_SEGMENT; i++)
  				seg->trbs[i].link.control |=
  					cpu_to_le32(TRB_CYCLE);
  		}
  		/* All endpoint rings have link TRBs */
  		xhci_link_segments(xhci, seg, seg->next, type);
  		seg = seg->next;
  	} while (seg != ring->first_seg);
  	ring->type = type;
  	xhci_initialize_ring_info(ring, cycle_state);
  	/* td list should be empty since all URBs have been cancelled,
  	 * but just in case...
  	 */
  	INIT_LIST_HEAD(&ring->td_list);
  }
  
  /*
   * Expand an existing ring.
   * Look for a cached ring or allocate a new ring which has same segment numbers
   * and link the two rings.
   */
  int xhci_ring_expansion(struct xhci_hcd *xhci, struct xhci_ring *ring,
  				unsigned int num_trbs, gfp_t flags)
  {
  	struct xhci_segment	*first;
  	struct xhci_segment	*last;
  	unsigned int		num_segs;
  	unsigned int		num_segs_needed;
  	int			ret;
  
  	num_segs_needed = (num_trbs + (TRBS_PER_SEGMENT - 1) - 1) /
  				(TRBS_PER_SEGMENT - 1);
  
  	/* Allocate number of segments we needed, or double the ring size */
  	num_segs = ring->num_segs > num_segs_needed ?
  			ring->num_segs : num_segs_needed;
  
  	ret = xhci_alloc_segments_for_ring(xhci, &first, &last,
  			num_segs, ring->cycle_state, ring->type, flags);
  	if (ret)
  		return -ENOMEM;
  
  	xhci_link_rings(xhci, ring, first, last, num_segs);
  	xhci_dbg_trace(xhci, trace_xhci_dbg_ring_expansion,
  			"ring expansion succeed, now has %d segments",
  			ring->num_segs);
  
  	return 0;
  }
  
  #define CTX_SIZE(_hcc) (HCC_64BYTE_CONTEXT(_hcc) ? 64 : 32)
  
  static struct xhci_container_ctx *xhci_alloc_container_ctx(struct xhci_hcd *xhci,
  						    int type, gfp_t flags)
  {
  	struct xhci_container_ctx *ctx;
  
  	if ((type != XHCI_CTX_TYPE_DEVICE) && (type != XHCI_CTX_TYPE_INPUT))
  		return NULL;
  
  	ctx = kzalloc(sizeof(*ctx), flags);
  	if (!ctx)
  		return NULL;
  
  	ctx->type = type;
  	ctx->size = HCC_64BYTE_CONTEXT(xhci->hcc_params) ? 2048 : 1024;
  	if (type == XHCI_CTX_TYPE_INPUT)
  		ctx->size += CTX_SIZE(xhci->hcc_params);
  
  	ctx->bytes = dma_pool_alloc(xhci->device_pool, flags, &ctx->dma);
  	if (!ctx->bytes) {
  		kfree(ctx);
  		return NULL;
  	}
  	memset(ctx->bytes, 0, ctx->size);
  	return ctx;
  }
  
  static void xhci_free_container_ctx(struct xhci_hcd *xhci,
  			     struct xhci_container_ctx *ctx)
  {
  	if (!ctx)
  		return;
  	dma_pool_free(xhci->device_pool, ctx->bytes, ctx->dma);
  	kfree(ctx);
  }
  
  struct xhci_input_control_ctx *xhci_get_input_control_ctx(struct xhci_hcd *xhci,
  					      struct xhci_container_ctx *ctx)
  {
  	if (ctx->type != XHCI_CTX_TYPE_INPUT)
  		return NULL;
  
  	return (struct xhci_input_control_ctx *)ctx->bytes;
  }
  
  struct xhci_slot_ctx *xhci_get_slot_ctx(struct xhci_hcd *xhci,
  					struct xhci_container_ctx *ctx)
  {
  	if (ctx->type == XHCI_CTX_TYPE_DEVICE)
  		return (struct xhci_slot_ctx *)ctx->bytes;
  
  	return (struct xhci_slot_ctx *)
  		(ctx->bytes + CTX_SIZE(xhci->hcc_params));
  }
  
  struct xhci_ep_ctx *xhci_get_ep_ctx(struct xhci_hcd *xhci,
  				    struct xhci_container_ctx *ctx,
  				    unsigned int ep_index)
  {
  	/* increment ep index by offset of start of ep ctx array */
  	ep_index++;
  	if (ctx->type == XHCI_CTX_TYPE_INPUT)
  		ep_index++;
  
  	return (struct xhci_ep_ctx *)
  		(ctx->bytes + (ep_index * CTX_SIZE(xhci->hcc_params)));
  }
  
  
  /***************** Streams structures manipulation *************************/
  
  static void xhci_free_stream_ctx(struct xhci_hcd *xhci,
  		unsigned int num_stream_ctxs,
  		struct xhci_stream_ctx *stream_ctx, dma_addr_t dma)
  {
  	struct device *dev = xhci_to_hcd(xhci)->self.controller;
  
  	if (num_stream_ctxs > MEDIUM_STREAM_ARRAY_SIZE)
  		dma_free_coherent(dev,
  				sizeof(struct xhci_stream_ctx)*num_stream_ctxs,
  				stream_ctx, dma);
  	else if (num_stream_ctxs <= SMALL_STREAM_ARRAY_SIZE)
  		return dma_pool_free(xhci->small_streams_pool,
  				stream_ctx, dma);
  	else
  		return dma_pool_free(xhci->medium_streams_pool,
  				stream_ctx, dma);
  }
  
  /*
   * The stream context array for each endpoint with bulk streams enabled can
   * vary in size, based on:
   *  - how many streams the endpoint supports,
   *  - the maximum primary stream array size the host controller supports,
   *  - and how many streams the device driver asks for.
   *
   * The stream context array must be a power of 2, and can be as small as
   * 64 bytes or as large as 1MB.
   */
  static struct xhci_stream_ctx *xhci_alloc_stream_ctx(struct xhci_hcd *xhci,
  		unsigned int num_stream_ctxs, dma_addr_t *dma,
  		gfp_t mem_flags)
  {
  	struct device *dev = xhci_to_hcd(xhci)->self.controller;
  
  	if (num_stream_ctxs > MEDIUM_STREAM_ARRAY_SIZE)
  		return dma_alloc_coherent(dev,
  				sizeof(struct xhci_stream_ctx)*num_stream_ctxs,
  				dma, mem_flags);
  	else if (num_stream_ctxs <= SMALL_STREAM_ARRAY_SIZE)
  		return dma_pool_alloc(xhci->small_streams_pool,
  				mem_flags, dma);
  	else
  		return dma_pool_alloc(xhci->medium_streams_pool,
  				mem_flags, dma);
  }
  
  struct xhci_ring *xhci_dma_to_transfer_ring(
  		struct xhci_virt_ep *ep,
  		u64 address)
  {
  	if (ep->ep_state & EP_HAS_STREAMS)
  		return radix_tree_lookup(&ep->stream_info->trb_address_map,
  				address >> TRB_SEGMENT_SHIFT);
  	return ep->ring;
  }
  
  struct xhci_ring *xhci_stream_id_to_ring(
  		struct xhci_virt_device *dev,
  		unsigned int ep_index,
  		unsigned int stream_id)
  {
  	struct xhci_virt_ep *ep = &dev->eps[ep_index];
  
  	if (stream_id == 0)
  		return ep->ring;
  	if (!ep->stream_info)
  		return NULL;
  
  	if (stream_id > ep->stream_info->num_streams)
  		return NULL;
  	return ep->stream_info->stream_rings[stream_id];
  }
  
  /*
   * Change an endpoint's internal structure so it supports stream IDs.  The
   * number of requested streams includes stream 0, which cannot be used by device
   * drivers.
   *
   * The number of stream contexts in the stream context array may be bigger than
   * the number of streams the driver wants to use.  This is because the number of
   * stream context array entries must be a power of two.
   *
   * We need a radix tree for mapping physical addresses of TRBs to which stream
   * ID they belong to.  We need to do this because the host controller won't tell
   * us which stream ring the TRB came from.  We could store the stream ID in an
   * event data TRB, but that doesn't help us for the cancellation case, since the
   * endpoint may stop before it reaches that event data TRB.
   *
   * The radix tree maps the upper portion of the TRB DMA address to a ring
   * segment that has the same upper portion of DMA addresses.  For example, say I
   * have segments of size 1KB, that are always 64-byte aligned.  A segment may
   * start at 0x10c91000 and end at 0x10c913f0.  If I use the upper 10 bits, the
   * key to the stream ID is 0x43244.  I can use the DMA address of the TRB to
   * pass the radix tree a key to get the right stream ID:
   *
   * 	0x10c90fff >> 10 = 0x43243
   * 	0x10c912c0 >> 10 = 0x43244
   * 	0x10c91400 >> 10 = 0x43245
   *
   * Obviously, only those TRBs with DMA addresses that are within the segment
   * will make the radix tree return the stream ID for that ring.
   *
   * Caveats for the radix tree:
   *
   * The radix tree uses an unsigned long as a key pair.  On 32-bit systems, an
   * unsigned long will be 32-bits; on a 64-bit system an unsigned long will be
   * 64-bits.  Since we only request 32-bit DMA addresses, we can use that as the
   * key on 32-bit or 64-bit systems (it would also be fine if we asked for 64-bit
   * PCI DMA addresses on a 64-bit system).  There might be a problem on 32-bit
   * extended systems (where the DMA address can be bigger than 32-bits),
   * if we allow the PCI dma mask to be bigger than 32-bits.  So don't do that.
   */
  struct xhci_stream_info *xhci_alloc_stream_info(struct xhci_hcd *xhci,
  		unsigned int num_stream_ctxs,
  		unsigned int num_streams, gfp_t mem_flags)
  {
  	struct xhci_stream_info *stream_info;
  	u32 cur_stream;
  	struct xhci_ring *cur_ring;
  	unsigned long key;
  	u64 addr;
  	int ret;
  
  	xhci_dbg(xhci, "Allocating %u streams and %u "
  			"stream context array entries.
  ",
  			num_streams, num_stream_ctxs);
  	if (xhci->cmd_ring_reserved_trbs == MAX_RSVD_CMD_TRBS) {
  		xhci_dbg(xhci, "Command ring has no reserved TRBs available
  ");
  		return NULL;
  	}
  	xhci->cmd_ring_reserved_trbs++;
  
  	stream_info = kzalloc(sizeof(struct xhci_stream_info), mem_flags);
  	if (!stream_info)
  		goto cleanup_trbs;
  
  	stream_info->num_streams = num_streams;
  	stream_info->num_stream_ctxs = num_stream_ctxs;
  
  	/* Initialize the array of virtual pointers to stream rings. */
  	stream_info->stream_rings = kzalloc(
  			sizeof(struct xhci_ring *)*num_streams,
  			mem_flags);
  	if (!stream_info->stream_rings)
  		goto cleanup_info;
  
  	/* Initialize the array of DMA addresses for stream rings for the HW. */
  	stream_info->stream_ctx_array = xhci_alloc_stream_ctx(xhci,
  			num_stream_ctxs, &stream_info->ctx_array_dma,
  			mem_flags);
  	if (!stream_info->stream_ctx_array)
  		goto cleanup_ctx;
  	memset(stream_info->stream_ctx_array, 0,
  			sizeof(struct xhci_stream_ctx)*num_stream_ctxs);
  
  	/* Allocate everything needed to free the stream rings later */
  	stream_info->free_streams_command =
  		xhci_alloc_command(xhci, true, true, mem_flags);
  	if (!stream_info->free_streams_command)
  		goto cleanup_ctx;
  
  	INIT_RADIX_TREE(&stream_info->trb_address_map, GFP_ATOMIC);
  
  	/* Allocate rings for all the streams that the driver will use,
  	 * and add their segment DMA addresses to the radix tree.
  	 * Stream 0 is reserved.
  	 */
  	for (cur_stream = 1; cur_stream < num_streams; cur_stream++) {
  		stream_info->stream_rings[cur_stream] =
  			xhci_ring_alloc(xhci, 2, 1, TYPE_STREAM, mem_flags);
  		cur_ring = stream_info->stream_rings[cur_stream];
  		if (!cur_ring)
  			goto cleanup_rings;
  		cur_ring->stream_id = cur_stream;
  		/* Set deq ptr, cycle bit, and stream context type */
  		addr = cur_ring->first_seg->dma |
  			SCT_FOR_CTX(SCT_PRI_TR) |
  			cur_ring->cycle_state;
  		stream_info->stream_ctx_array[cur_stream].stream_ring =
  			cpu_to_le64(addr);
  		xhci_dbg(xhci, "Setting stream %d ring ptr to 0x%08llx
  ",
  				cur_stream, (unsigned long long) addr);
  
  		key = (unsigned long)
  			(cur_ring->first_seg->dma >> TRB_SEGMENT_SHIFT);
  		ret = radix_tree_insert(&stream_info->trb_address_map,
  				key, cur_ring);
  		if (ret) {
  			xhci_ring_free(xhci, cur_ring);
  			stream_info->stream_rings[cur_stream] = NULL;
  			goto cleanup_rings;
  		}
  	}
  	/* Leave the other unused stream ring pointers in the stream context
  	 * array initialized to zero.  This will cause the xHC to give us an
  	 * error if the device asks for a stream ID we don't have setup (if it
  	 * was any other way, the host controller would assume the ring is
  	 * "empty" and wait forever for data to be queued to that stream ID).
  	 */
  
  	return stream_info;
  
  cleanup_rings:
  	for (cur_stream = 1; cur_stream < num_streams; cur_stream++) {
  		cur_ring = stream_info->stream_rings[cur_stream];
  		if (cur_ring) {
  			addr = cur_ring->first_seg->dma;
  			radix_tree_delete(&stream_info->trb_address_map,
  					addr >> TRB_SEGMENT_SHIFT);
  			xhci_ring_free(xhci, cur_ring);
  			stream_info->stream_rings[cur_stream] = NULL;
  		}
  	}
  	xhci_free_command(xhci, stream_info->free_streams_command);
  cleanup_ctx:
  	kfree(stream_info->stream_rings);
  cleanup_info:
  	kfree(stream_info);
  cleanup_trbs:
  	xhci->cmd_ring_reserved_trbs--;
  	return NULL;
  }
  /*
   * Sets the MaxPStreams field and the Linear Stream Array field.
   * Sets the dequeue pointer to the stream context array.
   */
  void xhci_setup_streams_ep_input_ctx(struct xhci_hcd *xhci,
  		struct xhci_ep_ctx *ep_ctx,
  		struct xhci_stream_info *stream_info)
  {
  	u32 max_primary_streams;
  	/* MaxPStreams is the number of stream context array entries, not the
  	 * number we're actually using.  Must be in 2^(MaxPstreams + 1) format.
  	 * fls(0) = 0, fls(0x1) = 1, fls(0x10) = 2, fls(0x100) = 3, etc.
  	 */
  	max_primary_streams = fls(stream_info->num_stream_ctxs) - 2;
  	xhci_dbg_trace(xhci,  trace_xhci_dbg_context_change,
  			"Setting number of stream ctx array entries to %u",
  			1 << (max_primary_streams + 1));
  	ep_ctx->ep_info &= cpu_to_le32(~EP_MAXPSTREAMS_MASK);
  	ep_ctx->ep_info |= cpu_to_le32(EP_MAXPSTREAMS(max_primary_streams)
  				       | EP_HAS_LSA);
  	ep_ctx->deq  = cpu_to_le64(stream_info->ctx_array_dma);
  }
  
  /*
   * Sets the MaxPStreams field and the Linear Stream Array field to 0.
   * Reinstalls the "normal" endpoint ring (at its previous dequeue mark,
   * not at the beginning of the ring).
   */
  void xhci_setup_no_streams_ep_input_ctx(struct xhci_hcd *xhci,
  		struct xhci_ep_ctx *ep_ctx,
  		struct xhci_virt_ep *ep)
  {
  	dma_addr_t addr;
  	ep_ctx->ep_info &= cpu_to_le32(~(EP_MAXPSTREAMS_MASK | EP_HAS_LSA));
  	addr = xhci_trb_virt_to_dma(ep->ring->deq_seg, ep->ring->dequeue);
  	ep_ctx->deq  = cpu_to_le64(addr | ep->ring->cycle_state);
  }
  
  /* Frees all stream contexts associated with the endpoint,
   *
   * Caller should fix the endpoint context streams fields.
   */
  void xhci_free_stream_info(struct xhci_hcd *xhci,
  		struct xhci_stream_info *stream_info)
  {
  	int cur_stream;
  	struct xhci_ring *cur_ring;
  	dma_addr_t addr;
  
  	if (!stream_info)
  		return;
  
  	for (cur_stream = 1; cur_stream < stream_info->num_streams;
  			cur_stream++) {
  		cur_ring = stream_info->stream_rings[cur_stream];
  		if (cur_ring) {
  			addr = cur_ring->first_seg->dma;
  			radix_tree_delete(&stream_info->trb_address_map,
  					addr >> TRB_SEGMENT_SHIFT);
  			xhci_ring_free(xhci, cur_ring);
  			stream_info->stream_rings[cur_stream] = NULL;
  		}
  	}
  	xhci_free_command(xhci, stream_info->free_streams_command);
  	xhci->cmd_ring_reserved_trbs--;
  	if (stream_info->stream_ctx_array)
  		xhci_free_stream_ctx(xhci,
  				stream_info->num_stream_ctxs,
  				stream_info->stream_ctx_array,
  				stream_info->ctx_array_dma);
  
  	kfree(stream_info->stream_rings);
  	kfree(stream_info);
  }
  
  
  /***************** Device context manipulation *************************/
  
  static void xhci_init_endpoint_timer(struct xhci_hcd *xhci,
  		struct xhci_virt_ep *ep)
  {
  	init_timer(&ep->stop_cmd_timer);
  	ep->stop_cmd_timer.data = (unsigned long) ep;
  	ep->stop_cmd_timer.function = xhci_stop_endpoint_command_watchdog;
  	ep->xhci = xhci;
  }
  
  static void xhci_free_tt_info(struct xhci_hcd *xhci,
  		struct xhci_virt_device *virt_dev,
  		int slot_id)
  {
  	struct list_head *tt_list_head;
  	struct xhci_tt_bw_info *tt_info, *next;
  	bool slot_found = false;
  
  	/* If the device never made it past the Set Address stage,
  	 * it may not have the real_port set correctly.
  	 */
  	if (virt_dev->real_port == 0 ||
  			virt_dev->real_port > HCS_MAX_PORTS(xhci->hcs_params1)) {
  		xhci_dbg(xhci, "Bad real port.
  ");
  		return;
  	}
  
  	tt_list_head = &(xhci->rh_bw[virt_dev->real_port - 1].tts);
  	list_for_each_entry_safe(tt_info, next, tt_list_head, tt_list) {
  		/* Multi-TT hubs will have more than one entry */
  		if (tt_info->slot_id == slot_id) {
  			slot_found = true;
  			list_del(&tt_info->tt_list);
  			kfree(tt_info);
  		} else if (slot_found) {
  			break;
  		}
  	}
  }
  
  int xhci_alloc_tt_info(struct xhci_hcd *xhci,
  		struct xhci_virt_device *virt_dev,
  		struct usb_device *hdev,
  		struct usb_tt *tt, gfp_t mem_flags)
  {
  	struct xhci_tt_bw_info		*tt_info;
  	unsigned int			num_ports;
  	int				i, j;
  
  	if (!tt->multi)
  		num_ports = 1;
  	else
  		num_ports = hdev->maxchild;
  
  	for (i = 0; i < num_ports; i++, tt_info++) {
  		struct xhci_interval_bw_table *bw_table;
  
  		tt_info = kzalloc(sizeof(*tt_info), mem_flags);
  		if (!tt_info)
  			goto free_tts;
  		INIT_LIST_HEAD(&tt_info->tt_list);
  		list_add(&tt_info->tt_list,
  				&xhci->rh_bw[virt_dev->real_port - 1].tts);
  		tt_info->slot_id = virt_dev->udev->slot_id;
  		if (tt->multi)
  			tt_info->ttport = i+1;
  		bw_table = &tt_info->bw_table;
  		for (j = 0; j < XHCI_MAX_INTERVAL; j++)
  			INIT_LIST_HEAD(&bw_table->interval_bw[j].endpoints);
  	}
  	return 0;
  
  free_tts:
  	xhci_free_tt_info(xhci, virt_dev, virt_dev->udev->slot_id);
  	return -ENOMEM;
  }
  
  
  /* All the xhci_tds in the ring's TD list should be freed at this point.
   * Should be called with xhci->lock held if there is any chance the TT lists
   * will be manipulated by the configure endpoint, allocate device, or update
   * hub functions while this function is removing the TT entries from the list.
   */
  void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id)
  {
  	struct xhci_virt_device *dev;
  	int i;
  	int old_active_eps = 0;
  
  	/* Slot ID 0 is reserved */
  	if (slot_id == 0 || !xhci->devs[slot_id])
  		return;
  
  	dev = xhci->devs[slot_id];
  	xhci->dcbaa->dev_context_ptrs[slot_id] = 0;
  	if (!dev)
  		return;
  
  	if (dev->tt_info)
  		old_active_eps = dev->tt_info->active_eps;
  
  	for (i = 0; i < 31; ++i) {
  		if (dev->eps[i].ring)
  			xhci_ring_free(xhci, dev->eps[i].ring);
  		if (dev->eps[i].stream_info)
  			xhci_free_stream_info(xhci,
  					dev->eps[i].stream_info);
  		/* Endpoints on the TT/root port lists should have been removed
  		 * when usb_disable_device() was called for the device.
  		 * We can't drop them anyway, because the udev might have gone
  		 * away by this point, and we can't tell what speed it was.
  		 */
  		if (!list_empty(&dev->eps[i].bw_endpoint_list))
  			xhci_warn(xhci, "Slot %u endpoint %u "
  					"not removed from BW list!
  ",
  					slot_id, i);
  	}
  	/* If this is a hub, free the TT(s) from the TT list */
  	xhci_free_tt_info(xhci, dev, slot_id);
  	/* If necessary, update the number of active TTs on this root port */
  	xhci_update_tt_active_eps(xhci, dev, old_active_eps);
  
  	if (dev->ring_cache) {
  		for (i = 0; i < dev->num_rings_cached; i++)
  			xhci_ring_free(xhci, dev->ring_cache[i]);
  		kfree(dev->ring_cache);
  	}
  
  	if (dev->in_ctx)
  		xhci_free_container_ctx(xhci, dev->in_ctx);
  	if (dev->out_ctx)
  		xhci_free_container_ctx(xhci, dev->out_ctx);
  
  	kfree(xhci->devs[slot_id]);
  	xhci->devs[slot_id] = NULL;
  }
  
  int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
  		struct usb_device *udev, gfp_t flags)
  {
  	struct xhci_virt_device *dev;
  	int i;
  
  	/* Slot ID 0 is reserved */
  	if (slot_id == 0 || xhci->devs[slot_id]) {
  		xhci_warn(xhci, "Bad Slot ID %d
  ", slot_id);
  		return 0;
  	}
  
  	xhci->devs[slot_id] = kzalloc(sizeof(*xhci->devs[slot_id]), flags);
  	if (!xhci->devs[slot_id])
  		return 0;
  	dev = xhci->devs[slot_id];
  
  	/* Allocate the (output) device context that will be used in the HC. */
  	dev->out_ctx = xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_DEVICE, flags);
  	if (!dev->out_ctx)
  		goto fail;
  
  	xhci_dbg(xhci, "Slot %d output ctx = 0x%llx (dma)
  ", slot_id,
  			(unsigned long long)dev->out_ctx->dma);
  
  	/* Allocate the (input) device context for address device command */
  	dev->in_ctx = xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_INPUT, flags);
  	if (!dev->in_ctx)
  		goto fail;
  
  	xhci_dbg(xhci, "Slot %d input ctx = 0x%llx (dma)
  ", slot_id,
  			(unsigned long long)dev->in_ctx->dma);
  
  	/* Initialize the cancellation list and watchdog timers for each ep */
  	for (i = 0; i < 31; i++) {
  		xhci_init_endpoint_timer(xhci, &dev->eps[i]);
  		INIT_LIST_HEAD(&dev->eps[i].cancelled_td_list);
  		INIT_LIST_HEAD(&dev->eps[i].bw_endpoint_list);
  	}
  
  	/* Allocate endpoint 0 ring */
  	dev->eps[0].ring = xhci_ring_alloc(xhci, 2, 1, TYPE_CTRL, flags);
  	if (!dev->eps[0].ring)
  		goto fail;
  
  	/* Allocate pointers to the ring cache */
  	dev->ring_cache = kzalloc(
  			sizeof(struct xhci_ring *)*XHCI_MAX_RINGS_CACHED,
  			flags);
  	if (!dev->ring_cache)
  		goto fail;
  	dev->num_rings_cached = 0;
  
  	init_completion(&dev->cmd_completion);
  	INIT_LIST_HEAD(&dev->cmd_list);
  	dev->udev = udev;
  
  	/* Point to output device context in dcbaa. */
  	xhci->dcbaa->dev_context_ptrs[slot_id] = cpu_to_le64(dev->out_ctx->dma);
  	xhci_dbg(xhci, "Set slot id %d dcbaa entry %p to 0x%llx
  ",
  		 slot_id,
  		 &xhci->dcbaa->dev_context_ptrs[slot_id],
  		 le64_to_cpu(xhci->dcbaa->dev_context_ptrs[slot_id]));
  
  	return 1;
  fail:
  	xhci_free_virt_device(xhci, slot_id);
  	return 0;
  }
  
  void xhci_copy_ep0_dequeue_into_input_ctx(struct xhci_hcd *xhci,
  		struct usb_device *udev)
  {
  	struct xhci_virt_device *virt_dev;
  	struct xhci_ep_ctx	*ep0_ctx;
  	struct xhci_ring	*ep_ring;
  
  	virt_dev = xhci->devs[udev->slot_id];
  	ep0_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, 0);
  	ep_ring = virt_dev->eps[0].ring;
  	/*
  	 * FIXME we don't keep track of the dequeue pointer very well after a
  	 * Set TR dequeue pointer, so we're setting the dequeue pointer of the
  	 * host to our enqueue pointer.  This should only be called after a
  	 * configured device has reset, so all control transfers should have
  	 * been completed or cancelled before the reset.
  	 */
  	ep0_ctx->deq = cpu_to_le64(xhci_trb_virt_to_dma(ep_ring->enq_seg,
  							ep_ring->enqueue)
  				   | ep_ring->cycle_state);
  }
  
  /*
   * The xHCI roothub may have ports of differing speeds in any order in the port
   * status registers.  xhci->port_array provides an array of the port speed for
   * each offset into the port status registers.
   *
   * The xHCI hardware wants to know the roothub port number that the USB device
   * is attached to (or the roothub port its ancestor hub is attached to).  All we
   * know is the index of that port under either the USB 2.0 or the USB 3.0
   * roothub, but that doesn't give us the real index into the HW port status
   * registers. Call xhci_find_raw_port_number() to get real index.
   */
  static u32 xhci_find_real_port_number(struct xhci_hcd *xhci,
  		struct usb_device *udev)
  {
  	struct usb_device *top_dev;
  	struct usb_hcd *hcd;
  
  	if (udev->speed == USB_SPEED_SUPER)
  		hcd = xhci->shared_hcd;
  	else
  		hcd = xhci->main_hcd;
  
  	for (top_dev = udev; top_dev->parent && top_dev->parent->parent;
  			top_dev = top_dev->parent)
  		/* Found device below root hub */;
  
  	return	xhci_find_raw_port_number(hcd, top_dev->portnum);
  }
  
  /* Setup an xHCI virtual device for a Set Address command */
  int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *udev)
  {
  	struct xhci_virt_device *dev;
  	struct xhci_ep_ctx	*ep0_ctx;
  	struct xhci_slot_ctx    *slot_ctx;
  	u32			port_num;
  	u32			max_packets;
  	struct usb_device *top_dev;
  
  	dev = xhci->devs[udev->slot_id];
  	/* Slot ID 0 is reserved */
  	if (udev->slot_id == 0 || !dev) {
  		xhci_warn(xhci, "Slot ID %d is not assigned to this device
  ",
  				udev->slot_id);
  		return -EINVAL;
  	}
  	ep0_ctx = xhci_get_ep_ctx(xhci, dev->in_ctx, 0);
  	slot_ctx = xhci_get_slot_ctx(xhci, dev->in_ctx);
  
  	/* 3) Only the control endpoint is valid - one endpoint context */
  	slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(1) | udev->route);
  	switch (udev->speed) {
  	case USB_SPEED_SUPER:
  		slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_SS);
  		max_packets = MAX_PACKET(512);
  		break;
  	case USB_SPEED_HIGH:
  		slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_HS);
  		max_packets = MAX_PACKET(64);
  		break;
  	/* USB core guesses at a 64-byte max packet first for FS devices */
  	case USB_SPEED_FULL:
  		slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_FS);
  		max_packets = MAX_PACKET(64);
  		break;
  	case USB_SPEED_LOW:
  		slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_LS);
  		max_packets = MAX_PACKET(8);
  		break;
  	case USB_SPEED_WIRELESS:
  		xhci_dbg(xhci, "FIXME xHCI doesn't support wireless speeds
  ");
  		return -EINVAL;
  		break;
  	default:
  		/* Speed was set earlier, this shouldn't happen. */
  		return -EINVAL;
  	}
  	/* Find the root hub port this device is under */
  	port_num = xhci_find_real_port_number(xhci, udev);
  	if (!port_num)
  		return -EINVAL;
  	slot_ctx->dev_info2 |= cpu_to_le32(ROOT_HUB_PORT(port_num));
  	/* Set the port number in the virtual_device to the faked port number */
  	for (top_dev = udev; top_dev->parent && top_dev->parent->parent;
  			top_dev = top_dev->parent)
  		/* Found device below root hub */;
  	dev->fake_port = top_dev->portnum;
  	dev->real_port = port_num;
  	xhci_dbg(xhci, "Set root hub portnum to %d
  ", port_num);
  	xhci_dbg(xhci, "Set fake root hub portnum to %d
  ", dev->fake_port);
  
  	/* Find the right bandwidth table that this device will be a part of.
  	 * If this is a full speed device attached directly to a root port (or a
  	 * decendent of one), it counts as a primary bandwidth domain, not a
  	 * secondary bandwidth domain under a TT.  An xhci_tt_info structure
  	 * will never be created for the HS root hub.
  	 */
  	if (!udev->tt || !udev->tt->hub->parent) {
  		dev->bw_table = &xhci->rh_bw[port_num - 1].bw_table;
  	} else {
  		struct xhci_root_port_bw_info *rh_bw;
  		struct xhci_tt_bw_info *tt_bw;
  
  		rh_bw = &xhci->rh_bw[port_num - 1];
  		/* Find the right TT. */
  		list_for_each_entry(tt_bw, &rh_bw->tts, tt_list) {
  			if (tt_bw->slot_id != udev->tt->hub->slot_id)
  				continue;
  
  			if (!dev->udev->tt->multi ||
  					(udev->tt->multi &&
  					 tt_bw->ttport == dev->udev->ttport)) {
  				dev->bw_table = &tt_bw->bw_table;
  				dev->tt_info = tt_bw;
  				break;
  			}
  		}
  		if (!dev->tt_info)
  			xhci_warn(xhci, "WARN: Didn't find a matching TT
  ");
  	}
  
  	/* Is this a LS/FS device under an external HS hub? */
  	if (udev->tt && udev->tt->hub->parent) {
  		slot_ctx->tt_info = cpu_to_le32(udev->tt->hub->slot_id |
  						(udev->ttport << 8));
  		if (udev->tt->multi)
  			slot_ctx->dev_info |= cpu_to_le32(DEV_MTT);
  	}
  	xhci_dbg(xhci, "udev->tt = %p
  ", udev->tt);
  	xhci_dbg(xhci, "udev->ttport = 0x%x
  ", udev->ttport);
  
  	/* Step 4 - ring already allocated */
  	/* Step 5 */
  	ep0_ctx->ep_info2 = cpu_to_le32(EP_TYPE(CTRL_EP));
  
  	/* EP 0 can handle "burst" sizes of 1, so Max Burst Size field is 0 */
  	ep0_ctx->ep_info2 |= cpu_to_le32(MAX_BURST(0) | ERROR_COUNT(3) |
  					 max_packets);
  
  	ep0_ctx->deq = cpu_to_le64(dev->eps[0].ring->first_seg->dma |
  				   dev->eps[0].ring->cycle_state);
  
  	/* Steps 7 and 8 were done in xhci_alloc_virt_device() */
  
  	return 0;
  }
  
  /*
   * Convert interval expressed as 2^(bInterval - 1) == interval into
   * straight exponent value 2^n == interval.
   *
   */
  static unsigned int xhci_parse_exponent_interval(struct usb_device *udev,
  		struct usb_host_endpoint *ep)
  {
  	unsigned int interval;
  
  	interval = clamp_val(ep->desc.bInterval, 1, 16) - 1;
  	if (interval != ep->desc.bInterval - 1)
  		dev_warn(&udev->dev,
  			 "ep %#x - rounding interval to %d %sframes
  ",
  			 ep->desc.bEndpointAddress,
  			 1 << interval,
  			 udev->speed == USB_SPEED_FULL ? "" : "micro");
  
  	if (udev->speed == USB_SPEED_FULL) {
  		/*
  		 * Full speed isoc endpoints specify interval in frames,
  		 * not microframes. We are using microframes everywhere,
  		 * so adjust accordingly.
  		 */
  		interval += 3;	/* 1 frame = 2^3 uframes */
  	}
  
  	return interval;
  }
  
  /*
   * Convert bInterval expressed in microframes (in 1-255 range) to exponent of
   * microframes, rounded down to nearest power of 2.
   */
  static unsigned int xhci_microframes_to_exponent(struct usb_device *udev,
  		struct usb_host_endpoint *ep, unsigned int desc_interval,
  		unsigned int min_exponent, unsigned int max_exponent)
  {
  	unsigned int interval;
  
  	interval = fls(desc_interval) - 1;
  	interval = clamp_val(interval, min_exponent, max_exponent);
  	if ((1 << interval) != desc_interval)
  		dev_warn(&udev->dev,
  			 "ep %#x - rounding interval to %d microframes, ep desc says %d microframes
  ",
  			 ep->desc.bEndpointAddress,
  			 1 << interval,
  			 desc_interval);
  
  	return interval;
  }
  
  static unsigned int xhci_parse_microframe_interval(struct usb_device *udev,
  		struct usb_host_endpoint *ep)
  {
  	if (ep->desc.bInterval == 0)
  		return 0;
  	return xhci_microframes_to_exponent(udev, ep,
  			ep->desc.bInterval, 0, 15);
  }
  
  
  static unsigned int xhci_parse_frame_interval(struct usb_device *udev,
  		struct usb_host_endpoint *ep)
  {
  	return xhci_microframes_to_exponent(udev, ep,
  			ep->desc.bInterval * 8, 3, 10);
  }
  
  /* Return the polling or NAK interval.
   *
   * The polling interval is expressed in "microframes".  If xHCI's Interval field
   * is set to N, it will service the endpoint every 2^(Interval)*125us.
   *
   * The NAK interval is one NAK per 1 to 255 microframes, or no NAKs if interval
   * is set to 0.
   */
  static unsigned int xhci_get_endpoint_interval(struct usb_device *udev,
  		struct usb_host_endpoint *ep)
  {
  	unsigned int interval = 0;
  
  	switch (udev->speed) {
  	case USB_SPEED_HIGH:
  		/* Max NAK rate */
  		if (usb_endpoint_xfer_control(&ep->desc) ||
  		    usb_endpoint_xfer_bulk(&ep->desc)) {
  			interval = xhci_parse_microframe_interval(udev, ep);
  			break;
  		}
  		/* Fall through - SS and HS isoc/int have same decoding */
  
  	case USB_SPEED_SUPER:
  		if (usb_endpoint_xfer_int(&ep->desc) ||
  		    usb_endpoint_xfer_isoc(&ep->desc)) {
  			interval = xhci_parse_exponent_interval(udev, ep);
  		}
  		break;
  
  	case USB_SPEED_FULL:
  		if (usb_endpoint_xfer_isoc(&ep->desc)) {
  			interval = xhci_parse_exponent_interval(udev, ep);
  			break;
  		}
  		/*
  		 * Fall through for interrupt endpoint interval decoding
  		 * since it uses the same rules as low speed interrupt
  		 * endpoints.
  		 */
  
  	case USB_SPEED_LOW:
  		if (usb_endpoint_xfer_int(&ep->desc) ||
  		    usb_endpoint_xfer_isoc(&ep->desc)) {
  
  			interval = xhci_parse_frame_interval(udev, ep);
  		}
  		break;
  
  	default:
  		BUG();
  	}
  	return EP_INTERVAL(interval);
  }
  
  /* The "Mult" field in the endpoint context is only set for SuperSpeed isoc eps.
   * High speed endpoint descriptors can define "the number of additional
   * transaction opportunities per microframe", but that goes in the Max Burst
   * endpoint context field.
   */
  static u32 xhci_get_endpoint_mult(struct usb_device *udev,
  		struct usb_host_endpoint *ep)
  {
  	if (udev->speed != USB_SPEED_SUPER ||
  			!usb_endpoint_xfer_isoc(&ep->desc))
  		return 0;
  	return ep->ss_ep_comp.bmAttributes;
  }
  
  static u32 xhci_get_endpoint_type(struct usb_device *udev,
  		struct usb_host_endpoint *ep)
  {
  	int in;
  	u32 type;
  
  	in = usb_endpoint_dir_in(&ep->desc);
  	if (usb_endpoint_xfer_control(&ep->desc)) {
  		type = EP_TYPE(CTRL_EP);
  	} else if (usb_endpoint_xfer_bulk(&ep->desc)) {
  		if (in)
  			type = EP_TYPE(BULK_IN_EP);
  		else
  			type = EP_TYPE(BULK_OUT_EP);
  	} else if (usb_endpoint_xfer_isoc(&ep->desc)) {
  		if (in)
  			type = EP_TYPE(ISOC_IN_EP);
  		else
  			type = EP_TYPE(ISOC_OUT_EP);
  	} else if (usb_endpoint_xfer_int(&ep->desc)) {
  		if (in)
  			type = EP_TYPE(INT_IN_EP);
  		else
  			type = EP_TYPE(INT_OUT_EP);
  	} else {
  		type = 0;
  	}
  	return type;
  }
  
  /* Return the maximum endpoint service interval time (ESIT) payload.
   * Basically, this is the maxpacket size, multiplied by the burst size
   * and mult size.
   */
  static u32 xhci_get_max_esit_payload(struct xhci_hcd *xhci,
  		struct usb_device *udev,
  		struct usb_host_endpoint *ep)
  {
  	int max_burst;
  	int max_packet;
  
  	/* Only applies for interrupt or isochronous endpoints */
  	if (usb_endpoint_xfer_control(&ep->desc) ||
  			usb_endpoint_xfer_bulk(&ep->desc))
  		return 0;
  
  	if (udev->speed == USB_SPEED_SUPER)
  		return le16_to_cpu(ep->ss_ep_comp.wBytesPerInterval);
  
  	max_packet = GET_MAX_PACKET(usb_endpoint_maxp(&ep->desc));
  	max_burst = (usb_endpoint_maxp(&ep->desc) & 0x1800) >> 11;
  	/* A 0 in max burst means 1 transfer per ESIT */
  	return max_packet * (max_burst + 1);
  }
  
  /* Set up an endpoint with one ring segment.  Do not allocate stream rings.
   * Drivers will have to call usb_alloc_streams() to do that.
   */
  int xhci_endpoint_init(struct xhci_hcd *xhci,
  		struct xhci_virt_device *virt_dev,
  		struct usb_device *udev,
  		struct usb_host_endpoint *ep,
  		gfp_t mem_flags)
  {
  	unsigned int ep_index;
  	struct xhci_ep_ctx *ep_ctx;
  	struct xhci_ring *ep_ring;
  	unsigned int max_packet;
  	unsigned int max_burst;
  	enum xhci_ring_type type;
  	u32 max_esit_payload;
  	u32 endpoint_type;
  
  	ep_index = xhci_get_endpoint_index(&ep->desc);
  	ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);
  
  	endpoint_type = xhci_get_endpoint_type(udev, ep);
  	if (!endpoint_type)
  		return -EINVAL;
  	ep_ctx->ep_info2 = cpu_to_le32(endpoint_type);
  
  	type = usb_endpoint_type(&ep->desc);
  	/* Set up the endpoint ring */
  	virt_dev->eps[ep_index].new_ring =
  		xhci_ring_alloc(xhci, 2, 1, type, mem_flags);
  	if (!virt_dev->eps[ep_index].new_ring) {
  		/* Attempt to use the ring cache */
  		if (virt_dev->num_rings_cached == 0)
  			return -ENOMEM;
  		virt_dev->eps[ep_index].new_ring =
  			virt_dev->ring_cache[virt_dev->num_rings_cached];
  		virt_dev->ring_cache[virt_dev->num_rings_cached] = NULL;
  		virt_dev->num_rings_cached--;
  		xhci_reinit_cached_ring(xhci, virt_dev->eps[ep_index].new_ring,
  					1, type);
  	}
  	virt_dev->eps[ep_index].skip = false;
  	ep_ring = virt_dev->eps[ep_index].new_ring;
  	ep_ctx->deq = cpu_to_le64(ep_ring->first_seg->dma | ep_ring->cycle_state);
  
  	ep_ctx->ep_info = cpu_to_le32(xhci_get_endpoint_interval(udev, ep)
  				      | EP_MULT(xhci_get_endpoint_mult(udev, ep)));
  
  	/* FIXME dig Mult and streams info out of ep companion desc */
  
  	/* Allow 3 retries for everything but isoc;
  	 * CErr shall be set to 0 for Isoch endpoints.
  	 */
  	if (!usb_endpoint_xfer_isoc(&ep->desc))
  		ep_ctx->ep_info2 |= cpu_to_le32(ERROR_COUNT(3));
  	else
  		ep_ctx->ep_info2 |= cpu_to_le32(ERROR_COUNT(0));
  
  	/* Set the max packet size and max burst */
  	max_packet = GET_MAX_PACKET(usb_endpoint_maxp(&ep->desc));
  	max_burst = 0;
  	switch (udev->speed) {
  	case USB_SPEED_SUPER:
  		/* dig out max burst from ep companion desc */
  		max_burst = ep->ss_ep_comp.bMaxBurst;
  		break;
  	case USB_SPEED_HIGH:
  		/* Some devices get this wrong */
  		if (usb_endpoint_xfer_bulk(&ep->desc))
  			max_packet = 512;
  		/* bits 11:12 specify the number of additional transaction
  		 * opportunities per microframe (USB 2.0, section 9.6.6)
  		 */
  		if (usb_endpoint_xfer_isoc(&ep->desc) ||
  				usb_endpoint_xfer_int(&ep->desc)) {
  			max_burst = (usb_endpoint_maxp(&ep->desc)
  				     & 0x1800) >> 11;
  		}
  		break;
  	case USB_SPEED_FULL:
  	case USB_SPEED_LOW:
  		break;
  	default:
  		BUG();
  	}
  	ep_ctx->ep_info2 |= cpu_to_le32(MAX_PACKET(max_packet) |
  			MAX_BURST(max_burst));
  	max_esit_payload = xhci_get_max_esit_payload(xhci, udev, ep);
  	ep_ctx->tx_info = cpu_to_le32(MAX_ESIT_PAYLOAD_FOR_EP(max_esit_payload));
  
  	/*
  	 * XXX no idea how to calculate the average TRB buffer length for bulk
  	 * endpoints, as the driver gives us no clue how big each scatter gather
  	 * list entry (or buffer) is going to be.
  	 *
  	 * For isochronous and interrupt endpoints, we set it to the max
  	 * available, until we have new API in the USB core to allow drivers to
  	 * declare how much bandwidth they actually need.
  	 *
  	 * Normally, it would be calculated by taking the total of the buffer
  	 * lengths in the TD and then dividing by the number of TRBs in a TD,
  	 * including link TRBs, No-op TRBs, and Event data TRBs.  Since we don't
  	 * use Event Data TRBs, and we don't chain in a link TRB on short
  	 * transfers, we're basically dividing by 1.
  	 *
  	 * xHCI 1.0 specification indicates that the Average TRB Length should
  	 * be set to 8 for control endpoints.
  	 */
  	if (usb_endpoint_xfer_control(&ep->desc) && xhci->hci_version == 0x100)
  		ep_ctx->tx_info |= cpu_to_le32(AVG_TRB_LENGTH_FOR_EP(8));
  	else
  		ep_ctx->tx_info |=
  			 cpu_to_le32(AVG_TRB_LENGTH_FOR_EP(max_esit_payload));
  
  	/* FIXME Debug endpoint context */
  	return 0;
  }
  
  void xhci_endpoint_zero(struct xhci_hcd *xhci,
  		struct xhci_virt_device *virt_dev,
  		struct usb_host_endpoint *ep)
  {
  	unsigned int ep_index;
  	struct xhci_ep_ctx *ep_ctx;
  
  	ep_index = xhci_get_endpoint_index(&ep->desc);
  	ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);
  
  	ep_ctx->ep_info = 0;
  	ep_ctx->ep_info2 = 0;
  	ep_ctx->deq = 0;
  	ep_ctx->tx_info = 0;
  	/* Don't free the endpoint ring until the set interface or configuration
  	 * request succeeds.
  	 */
  }
  
  void xhci_clear_endpoint_bw_info(struct xhci_bw_info *bw_info)
  {
  	bw_info->ep_interval = 0;
  	bw_info->mult = 0;
  	bw_info->num_packets = 0;
  	bw_info->max_packet_size = 0;
  	bw_info->type = 0;
  	bw_info->max_esit_payload = 0;
  }
  
  void xhci_update_bw_info(struct xhci_hcd *xhci,
  		struct xhci_container_ctx *in_ctx,
  		struct xhci_input_control_ctx *ctrl_ctx,
  		struct xhci_virt_device *virt_dev)
  {
  	struct xhci_bw_info *bw_info;
  	struct xhci_ep_ctx *ep_ctx;
  	unsigned int ep_type;
  	int i;
  
  	for (i = 1; i < 31; ++i) {
  		bw_info = &virt_dev->eps[i].bw_info;
  
  		/* We can't tell what endpoint type is being dropped, but
  		 * unconditionally clearing the bandwidth info for non-periodic
  		 * endpoints should be harmless because the info will never be
  		 * set in the first place.
  		 */
  		if (!EP_IS_ADDED(ctrl_ctx, i) && EP_IS_DROPPED(ctrl_ctx, i)) {
  			/* Dropped endpoint */
  			xhci_clear_endpoint_bw_info(bw_info);
  			continue;
  		}
  
  		if (EP_IS_ADDED(ctrl_ctx, i)) {
  			ep_ctx = xhci_get_ep_ctx(xhci, in_ctx, i);
  			ep_type = CTX_TO_EP_TYPE(le32_to_cpu(ep_ctx->ep_info2));
  
  			/* Ignore non-periodic endpoints */
  			if (ep_type != ISOC_OUT_EP && ep_type != INT_OUT_EP &&
  					ep_type != ISOC_IN_EP &&
  					ep_type != INT_IN_EP)
  				continue;
  
  			/* Added or changed endpoint */
  			bw_info->ep_interval = CTX_TO_EP_INTERVAL(
  					le32_to_cpu(ep_ctx->ep_info));
  			/* Number of packets and mult are zero-based in the
  			 * input context, but we want one-based for the
  			 * interval table.
  			 */
  			bw_info->mult = CTX_TO_EP_MULT(
  					le32_to_cpu(ep_ctx->ep_info)) + 1;
  			bw_info->num_packets = CTX_TO_MAX_BURST(
  					le32_to_cpu(ep_ctx->ep_info2)) + 1;
  			bw_info->max_packet_size = MAX_PACKET_DECODED(
  					le32_to_cpu(ep_ctx->ep_info2));
  			bw_info->type = ep_type;
  			bw_info->max_esit_payload = CTX_TO_MAX_ESIT_PAYLOAD(
  					le32_to_cpu(ep_ctx->tx_info));
  		}
  	}
  }
  
  /* Copy output xhci_ep_ctx to the input xhci_ep_ctx copy.
   * Useful when you want to change one particular aspect of the endpoint and then
   * issue a configure endpoint command.
   */
  void xhci_endpoint_copy(struct xhci_hcd *xhci,
  		struct xhci_container_ctx *in_ctx,
  		struct xhci_container_ctx *out_ctx,
  		unsigned int ep_index)
  {
  	struct xhci_ep_ctx *out_ep_ctx;
  	struct xhci_ep_ctx *in_ep_ctx;
  
  	out_ep_ctx = xhci_get_ep_ctx(xhci, out_ctx, ep_index);
  	in_ep_ctx = xhci_get_ep_ctx(xhci, in_ctx, ep_index);
  
  	in_ep_ctx->ep_info = out_ep_ctx->ep_info;
  	in_ep_ctx->ep_info2 = out_ep_ctx->ep_info2;
  	in_ep_ctx->deq = out_ep_ctx->deq;
  	in_ep_ctx->tx_info = out_ep_ctx->tx_info;
  }
  
  /* Copy output xhci_slot_ctx to the input xhci_slot_ctx.
   * Useful when you want to change one particular aspect of the endpoint and then
   * issue a configure endpoint command.  Only the context entries field matters,
   * but we'll copy the whole thing anyway.
   */
  void xhci_slot_copy(struct xhci_hcd *xhci,
  		struct xhci_container_ctx *in_ctx,
  		struct xhci_container_ctx *out_ctx)
  {
  	struct xhci_slot_ctx *in_slot_ctx;
  	struct xhci_slot_ctx *out_slot_ctx;
  
  	in_slot_ctx = xhci_get_slot_ctx(xhci, in_ctx);
  	out_slot_ctx = xhci_get_slot_ctx(xhci, out_ctx);
  
  	in_slot_ctx->dev_info = out_slot_ctx->dev_info;
  	in_slot_ctx->dev_info2 = out_slot_ctx->dev_info2;
  	in_slot_ctx->tt_info = out_slot_ctx->tt_info;
  	in_slot_ctx->dev_state = out_slot_ctx->dev_state;
  }
  
  /* Set up the scratchpad buffer array and scratchpad buffers, if needed. */
  static int scratchpad_alloc(struct xhci_hcd *xhci, gfp_t flags)
  {
  	int i;
  	struct device *dev = xhci_to_hcd(xhci)->self.controller;
  	int num_sp = HCS_MAX_SCRATCHPAD(xhci->hcs_params2);
  
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Allocating %d scratchpad buffers", num_sp);
  
  	if (!num_sp)
  		return 0;
  
  	xhci->scratchpad = kzalloc(sizeof(*xhci->scratchpad), flags);
  	if (!xhci->scratchpad)
  		goto fail_sp;
  
  	xhci->scratchpad->sp_array = dma_alloc_coherent(dev,
  				     num_sp * sizeof(u64),
  				     &xhci->scratchpad->sp_dma, flags);
  	if (!xhci->scratchpad->sp_array)
  		goto fail_sp2;
  
  	xhci->scratchpad->sp_buffers = kzalloc(sizeof(void *) * num_sp, flags);
  	if (!xhci->scratchpad->sp_buffers)
  		goto fail_sp3;
  
  	xhci->scratchpad->sp_dma_buffers =
  		kzalloc(sizeof(dma_addr_t) * num_sp, flags);
  
  	if (!xhci->scratchpad->sp_dma_buffers)
  		goto fail_sp4;
  
  	xhci->dcbaa->dev_context_ptrs[0] = cpu_to_le64(xhci->scratchpad->sp_dma);
  	for (i = 0; i < num_sp; i++) {
  		dma_addr_t dma;
  		void *buf = dma_alloc_coherent(dev, xhci->page_size, &dma,
  				flags);
  		if (!buf)
  			goto fail_sp5;
  
  		xhci->scratchpad->sp_array[i] = dma;
  		xhci->scratchpad->sp_buffers[i] = buf;
  		xhci->scratchpad->sp_dma_buffers[i] = dma;
  	}
  
  	return 0;
  
   fail_sp5:
  	for (i = i - 1; i >= 0; i--) {
  		dma_free_coherent(dev, xhci->page_size,
  				    xhci->scratchpad->sp_buffers[i],
  				    xhci->scratchpad->sp_dma_buffers[i]);
  	}
  	kfree(xhci->scratchpad->sp_dma_buffers);
  
   fail_sp4:
  	kfree(xhci->scratchpad->sp_buffers);
  
   fail_sp3:
  	dma_free_coherent(dev, num_sp * sizeof(u64),
  			    xhci->scratchpad->sp_array,
  			    xhci->scratchpad->sp_dma);
  
   fail_sp2:
  	kfree(xhci->scratchpad);
  	xhci->scratchpad = NULL;
  
   fail_sp:
  	return -ENOMEM;
  }
  
  static void scratchpad_free(struct xhci_hcd *xhci)
  {
  	int num_sp;
  	int i;
  	struct device *dev = xhci_to_hcd(xhci)->self.controller;
  
  	if (!xhci->scratchpad)
  		return;
  
  	num_sp = HCS_MAX_SCRATCHPAD(xhci->hcs_params2);
  
  	for (i = 0; i < num_sp; i++) {
  		dma_free_coherent(dev, xhci->page_size,
  				    xhci->scratchpad->sp_buffers[i],
  				    xhci->scratchpad->sp_dma_buffers[i]);
  	}
  	kfree(xhci->scratchpad->sp_dma_buffers);
  	kfree(xhci->scratchpad->sp_buffers);
  	dma_free_coherent(dev, num_sp * sizeof(u64),
  			    xhci->scratchpad->sp_array,
  			    xhci->scratchpad->sp_dma);
  	kfree(xhci->scratchpad);
  	xhci->scratchpad = NULL;
  }
  
  struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
  		bool allocate_in_ctx, bool allocate_completion,
  		gfp_t mem_flags)
  {
  	struct xhci_command *command;
  
  	command = kzalloc(sizeof(*command), mem_flags);
  	if (!command)
  		return NULL;
  
  	if (allocate_in_ctx) {
  		command->in_ctx =
  			xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_INPUT,
  					mem_flags);
  		if (!command->in_ctx) {
  			kfree(command);
  			return NULL;
  		}
  	}
  
  	if (allocate_completion) {
  		command->completion =
  			kzalloc(sizeof(struct completion), mem_flags);
  		if (!command->completion) {
  			xhci_free_container_ctx(xhci, command->in_ctx);
  			kfree(command);
  			return NULL;
  		}
  		init_completion(command->completion);
  	}
  
  	command->status = 0;
  	INIT_LIST_HEAD(&command->cmd_list);
  	return command;
  }
  
  void xhci_urb_free_priv(struct xhci_hcd *xhci, struct urb_priv *urb_priv)
  {
  	if (urb_priv) {
  		kfree(urb_priv->td[0]);
  		kfree(urb_priv);
  	}
  }
  
  void xhci_free_command(struct xhci_hcd *xhci,
  		struct xhci_command *command)
  {
  	xhci_free_container_ctx(xhci,
  			command->in_ctx);
  	kfree(command->completion);
  	kfree(command);
  }
  
  void xhci_mem_cleanup(struct xhci_hcd *xhci)
  {
  	struct device	*dev = xhci_to_hcd(xhci)->self.controller;
  	struct xhci_cd  *cur_cd, *next_cd;
  	int size;
  	int i, j, num_ports;
  
  	/* Free the Event Ring Segment Table and the actual Event Ring */
  	size = sizeof(struct xhci_erst_entry)*(xhci->erst.num_entries);
  	if (xhci->erst.entries)
  		dma_free_coherent(dev, size,
  				xhci->erst.entries, xhci->erst.erst_dma_addr);
  	xhci->erst.entries = NULL;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed ERST");
  	if (xhci->event_ring)
  		xhci_ring_free(xhci, xhci->event_ring);
  	xhci->event_ring = NULL;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed event ring");
  
  	if (xhci->lpm_command)
  		xhci_free_command(xhci, xhci->lpm_command);
  	xhci->cmd_ring_reserved_trbs = 0;
  	if (xhci->cmd_ring)
  		xhci_ring_free(xhci, xhci->cmd_ring);
  	xhci->cmd_ring = NULL;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed command ring");
  	list_for_each_entry_safe(cur_cd, next_cd,
  			&xhci->cancel_cmd_list, cancel_cmd_list) {
  		list_del(&cur_cd->cancel_cmd_list);
  		kfree(cur_cd);
  	}
  
  	num_ports = HCS_MAX_PORTS(xhci->hcs_params1);
  	for (i = 0; i < num_ports && xhci->rh_bw; i++) {
  		struct xhci_interval_bw_table *bwt = &xhci->rh_bw[i].bw_table;
  		for (j = 0; j < XHCI_MAX_INTERVAL; j++) {
  			struct list_head *ep = &bwt->interval_bw[j].endpoints;
  			while (!list_empty(ep))
  				list_del_init(ep->next);
  		}
  	}
  
  	for (i = 1; i < MAX_HC_SLOTS; ++i)
  		xhci_free_virt_device(xhci, i);
  
  	if (xhci->segment_pool)
  		dma_pool_destroy(xhci->segment_pool);
  	xhci->segment_pool = NULL;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed segment pool");
  
  	if (xhci->device_pool)
  		dma_pool_destroy(xhci->device_pool);
  	xhci->device_pool = NULL;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed device context pool");
  
  	if (xhci->small_streams_pool)
  		dma_pool_destroy(xhci->small_streams_pool);
  	xhci->small_streams_pool = NULL;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Freed small stream array pool");
  
  	if (xhci->medium_streams_pool)
  		dma_pool_destroy(xhci->medium_streams_pool);
  	xhci->medium_streams_pool = NULL;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Freed medium stream array pool");
  
  	if (xhci->dcbaa)
  		dma_free_coherent(dev, sizeof(*xhci->dcbaa),
  				xhci->dcbaa, xhci->dcbaa->dma);
  	xhci->dcbaa = NULL;
  
  	scratchpad_free(xhci);
  
  	if (!xhci->rh_bw)
  		goto no_bw;
  
  	for (i = 0; i < num_ports; i++) {
  		struct xhci_tt_bw_info *tt, *n;
  		list_for_each_entry_safe(tt, n, &xhci->rh_bw[i].tts, tt_list) {
  			list_del(&tt->tt_list);
  			kfree(tt);
  		}
  	}
  
  no_bw:
  	xhci->num_usb2_ports = 0;
  	xhci->num_usb3_ports = 0;
  	xhci->num_active_eps = 0;
  	kfree(xhci->usb2_ports);
  	kfree(xhci->usb3_ports);
  	kfree(xhci->port_array);
  	kfree(xhci->rh_bw);
  	kfree(xhci->ext_caps);
  
  	xhci->page_size = 0;
  	xhci->page_shift = 0;
  	xhci->bus_state[0].bus_suspended = 0;
  	xhci->bus_state[1].bus_suspended = 0;
  }
  
  static int xhci_test_trb_in_td(struct xhci_hcd *xhci,
  		struct xhci_segment *input_seg,
  		union xhci_trb *start_trb,
  		union xhci_trb *end_trb,
  		dma_addr_t input_dma,
  		struct xhci_segment *result_seg,
  		char *test_name, int test_number)
  {
  	unsigned long long start_dma;
  	unsigned long long end_dma;
  	struct xhci_segment *seg;
  
  	start_dma = xhci_trb_virt_to_dma(input_seg, start_trb);
  	end_dma = xhci_trb_virt_to_dma(input_seg, end_trb);
  
  	seg = trb_in_td(input_seg, start_trb, end_trb, input_dma);
  	if (seg != result_seg) {
  		xhci_warn(xhci, "WARN: %s TRB math test %d failed!
  ",
  				test_name, test_number);
  		xhci_warn(xhci, "Tested TRB math w/ seg %p and "
  				"input DMA 0x%llx
  ",
  				input_seg,
  				(unsigned long long) input_dma);
  		xhci_warn(xhci, "starting TRB %p (0x%llx DMA), "
  				"ending TRB %p (0x%llx DMA)
  ",
  				start_trb, start_dma,
  				end_trb, end_dma);
  		xhci_warn(xhci, "Expected seg %p, got seg %p
  ",
  				result_seg, seg);
  		return -1;
  	}
  	return 0;
  }
  
  /* TRB math checks for xhci_trb_in_td(), using the command and event rings. */
  static int xhci_check_trb_in_td_math(struct xhci_hcd *xhci, gfp_t mem_flags)
  {
  	struct {
  		dma_addr_t		input_dma;
  		struct xhci_segment	*result_seg;
  	} simple_test_vector [] = {
  		/* A zeroed DMA field should fail */
  		{ 0, NULL },
  		/* One TRB before the ring start should fail */
  		{ xhci->event_ring->first_seg->dma - 16, NULL },
  		/* One byte before the ring start should fail */
  		{ xhci->event_ring->first_seg->dma - 1, NULL },
  		/* Starting TRB should succeed */
  		{ xhci->event_ring->first_seg->dma, xhci->event_ring->first_seg },
  		/* Ending TRB should succeed */
  		{ xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT - 1)*16,
  			xhci->event_ring->first_seg },
  		/* One byte after the ring end should fail */
  		{ xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT - 1)*16 + 1, NULL },
  		/* One TRB after the ring end should fail */
  		{ xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT)*16, NULL },
  		/* An address of all ones should fail */
  		{ (dma_addr_t) (~0), NULL },
  	};
  	struct {
  		struct xhci_segment	*input_seg;
  		union xhci_trb		*start_trb;
  		union xhci_trb		*end_trb;
  		dma_addr_t		input_dma;
  		struct xhci_segment	*result_seg;
  	} complex_test_vector [] = {
  		/* Test feeding a valid DMA address from a different ring */
  		{	.input_seg = xhci->event_ring->first_seg,
  			.start_trb = xhci->event_ring->first_seg->trbs,
  			.end_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
  			.input_dma = xhci->cmd_ring->first_seg->dma,
  			.result_seg = NULL,
  		},
  		/* Test feeding a valid end TRB from a different ring */
  		{	.input_seg = xhci->event_ring->first_seg,
  			.start_trb = xhci->event_ring->first_seg->trbs,
  			.end_trb = &xhci->cmd_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
  			.input_dma = xhci->cmd_ring->first_seg->dma,
  			.result_seg = NULL,
  		},
  		/* Test feeding a valid start and end TRB from a different ring */
  		{	.input_seg = xhci->event_ring->first_seg,
  			.start_trb = xhci->cmd_ring->first_seg->trbs,
  			.end_trb = &xhci->cmd_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
  			.input_dma = xhci->cmd_ring->first_seg->dma,
  			.result_seg = NULL,
  		},
  		/* TRB in this ring, but after this TD */
  		{	.input_seg = xhci->event_ring->first_seg,
  			.start_trb = &xhci->event_ring->first_seg->trbs[0],
  			.end_trb = &xhci->event_ring->first_seg->trbs[3],
  			.input_dma = xhci->event_ring->first_seg->dma + 4*16,
  			.result_seg = NULL,
  		},
  		/* TRB in this ring, but before this TD */
  		{	.input_seg = xhci->event_ring->first_seg,
  			.start_trb = &xhci->event_ring->first_seg->trbs[3],
  			.end_trb = &xhci->event_ring->first_seg->trbs[6],
  			.input_dma = xhci->event_ring->first_seg->dma + 2*16,
  			.result_seg = NULL,
  		},
  		/* TRB in this ring, but after this wrapped TD */
  		{	.input_seg = xhci->event_ring->first_seg,
  			.start_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 3],
  			.end_trb = &xhci->event_ring->first_seg->trbs[1],
  			.input_dma = xhci->event_ring->first_seg->dma + 2*16,
  			.result_seg = NULL,
  		},
  		/* TRB in this ring, but before this wrapped TD */
  		{	.input_seg = xhci->event_ring->first_seg,
  			.start_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 3],
  			.end_trb = &xhci->event_ring->first_seg->trbs[1],
  			.input_dma = xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT - 4)*16,
  			.result_seg = NULL,
  		},
  		/* TRB not in this ring, and we have a wrapped TD */
  		{	.input_seg = xhci->event_ring->first_seg,
  			.start_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 3],
  			.end_trb = &xhci->event_ring->first_seg->trbs[1],
  			.input_dma = xhci->cmd_ring->first_seg->dma + 2*16,
  			.result_seg = NULL,
  		},
  	};
  
  	unsigned int num_tests;
  	int i, ret;
  
  	num_tests = ARRAY_SIZE(simple_test_vector);
  	for (i = 0; i < num_tests; i++) {
  		ret = xhci_test_trb_in_td(xhci,
  				xhci->event_ring->first_seg,
  				xhci->event_ring->first_seg->trbs,
  				&xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
  				simple_test_vector[i].input_dma,
  				simple_test_vector[i].result_seg,
  				"Simple", i);
  		if (ret < 0)
  			return ret;
  	}
  
  	num_tests = ARRAY_SIZE(complex_test_vector);
  	for (i = 0; i < num_tests; i++) {
  		ret = xhci_test_trb_in_td(xhci,
  				complex_test_vector[i].input_seg,
  				complex_test_vector[i].start_trb,
  				complex_test_vector[i].end_trb,
  				complex_test_vector[i].input_dma,
  				complex_test_vector[i].result_seg,
  				"Complex", i);
  		if (ret < 0)
  			return ret;
  	}
  	xhci_dbg(xhci, "TRB math tests passed.
  ");
  	return 0;
  }
  
  static void xhci_set_hc_event_deq(struct xhci_hcd *xhci)
  {
  	u64 temp;
  	dma_addr_t deq;
  
  	deq = xhci_trb_virt_to_dma(xhci->event_ring->deq_seg,
  			xhci->event_ring->dequeue);
  	if (deq == 0 && !in_interrupt())
  		xhci_warn(xhci, "WARN something wrong with SW event ring "
  				"dequeue ptr.
  ");
  	/* Update HC event ring dequeue pointer */
  	temp = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
  	temp &= ERST_PTR_MASK;
  	/* Don't clear the EHB bit (which is RW1C) because
  	 * there might be more events to service.
  	 */
  	temp &= ~ERST_EHB;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// Write event ring dequeue pointer, "
  			"preserving EHB bit");
  	xhci_write_64(xhci, ((u64) deq & (u64) ~ERST_PTR_MASK) | temp,
  			&xhci->ir_set->erst_dequeue);
  }
  
  static void xhci_add_in_port(struct xhci_hcd *xhci, unsigned int num_ports,
  		__le32 __iomem *addr, u8 major_revision, int max_caps)
  {
  	u32 temp, port_offset, port_count;
  	int i;
  
  	if (major_revision > 0x03) {
  		xhci_warn(xhci, "Ignoring unknown port speed, "
  				"Ext Cap %p, revision = 0x%x
  ",
  				addr, major_revision);
  		/* Ignoring port protocol we can't understand. FIXME */
  		return;
  	}
  
  	/* Port offset and count in the third dword, see section 7.2 */
  	temp = readl(addr + 2);
  	port_offset = XHCI_EXT_PORT_OFF(temp);
  	port_count = XHCI_EXT_PORT_COUNT(temp);
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Ext Cap %p, port offset = %u, "
  			"count = %u, revision = 0x%x",
  			addr, port_offset, port_count, major_revision);
  	/* Port count includes the current port offset */
  	if (port_offset == 0 || (port_offset + port_count - 1) > num_ports)
  		/* WTF? "Valid values are ‘1’ to MaxPorts" */
  		return;
  
  	/* cache usb2 port capabilities */
  	if (major_revision < 0x03 && xhci->num_ext_caps < max_caps)
  		xhci->ext_caps[xhci->num_ext_caps++] = temp;
  
  	/* Check the host's USB2 LPM capability */
  	if ((xhci->hci_version == 0x96) && (major_revision != 0x03) &&
  			(temp & XHCI_L1C)) {
  		xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  				"xHCI 0.96: support USB2 software lpm");
  		xhci->sw_lpm_support = 1;
  	}
  
  	if ((xhci->hci_version >= 0x100) && (major_revision != 0x03)) {
  		xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  				"xHCI 1.0: support USB2 software lpm");
  		xhci->sw_lpm_support = 1;
  		if (temp & XHCI_HLC) {
  			xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  					"xHCI 1.0: support USB2 hardware lpm");
  			xhci->hw_lpm_support = 1;
  		}
  	}
  
  	port_offset--;
  	for (i = port_offset; i < (port_offset + port_count); i++) {
  		/* Duplicate entry.  Ignore the port if the revisions differ. */
  		if (xhci->port_array[i] != 0) {
  			xhci_warn(xhci, "Duplicate port entry, Ext Cap %p,"
  					" port %u
  ", addr, i);
  			xhci_warn(xhci, "Port was marked as USB %u, "
  					"duplicated as USB %u
  ",
  					xhci->port_array[i], major_revision);
  			/* Only adjust the roothub port counts if we haven't
  			 * found a similar duplicate.
  			 */
  			if (xhci->port_array[i] != major_revision &&
  				xhci->port_array[i] != DUPLICATE_ENTRY) {
  				if (xhci->port_array[i] == 0x03)
  					xhci->num_usb3_ports--;
  				else
  					xhci->num_usb2_ports--;
  				xhci->port_array[i] = DUPLICATE_ENTRY;
  			}
  			/* FIXME: Should we disable the port? */
  			continue;
  		}
  		xhci->port_array[i] = major_revision;
  		if (major_revision == 0x03)
  			xhci->num_usb3_ports++;
  		else
  			xhci->num_usb2_ports++;
  	}
  	/* FIXME: Should we disable ports not in the Extended Capabilities? */
  }
  
  /*
   * Scan the Extended Capabilities for the "Supported Protocol Capabilities" that
   * specify what speeds each port is supposed to be.  We can't count on the port
   * speed bits in the PORTSC register being correct until a device is connected,
   * but we need to set up the two fake roothubs with the correct number of USB
   * 3.0 and USB 2.0 ports at host controller initialization time.
   */
  static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
  {
  	__le32 __iomem *addr, *tmp_addr;
  	u32 offset, tmp_offset;
  	unsigned int num_ports;
  	int i, j, port_index;
  	int cap_count = 0;
  
  	addr = &xhci->cap_regs->hcc_params;
  	offset = XHCI_HCC_EXT_CAPS(readl(addr));
  	if (offset == 0) {
  		xhci_err(xhci, "No Extended Capability registers, "
  				"unable to set up roothub.
  ");
  		return -ENODEV;
  	}
  
  	num_ports = HCS_MAX_PORTS(xhci->hcs_params1);
  	xhci->port_array = kzalloc(sizeof(*xhci->port_array)*num_ports, flags);
  	if (!xhci->port_array)
  		return -ENOMEM;
  
  	xhci->rh_bw = kzalloc(sizeof(*xhci->rh_bw)*num_ports, flags);
  	if (!xhci->rh_bw)
  		return -ENOMEM;
  	for (i = 0; i < num_ports; i++) {
  		struct xhci_interval_bw_table *bw_table;
  
  		INIT_LIST_HEAD(&xhci->rh_bw[i].tts);
  		bw_table = &xhci->rh_bw[i].bw_table;
  		for (j = 0; j < XHCI_MAX_INTERVAL; j++)
  			INIT_LIST_HEAD(&bw_table->interval_bw[j].endpoints);
  	}
  
  	/*
  	 * For whatever reason, the first capability offset is from the
  	 * capability register base, not from the HCCPARAMS register.
  	 * See section 5.3.6 for offset calculation.
  	 */
  	addr = &xhci->cap_regs->hc_capbase + offset;
  
  	tmp_addr = addr;
  	tmp_offset = offset;
  
  	/* count extended protocol capability entries for later caching */
  	do {
  		u32 cap_id;
  		cap_id = readl(tmp_addr);
  		if (XHCI_EXT_CAPS_ID(cap_id) == XHCI_EXT_CAPS_PROTOCOL)
  			cap_count++;
  		tmp_offset = XHCI_EXT_CAPS_NEXT(cap_id);
  		tmp_addr += tmp_offset;
  	} while (tmp_offset);
  
  	xhci->ext_caps = kzalloc(sizeof(*xhci->ext_caps) * cap_count, flags);
  	if (!xhci->ext_caps)
  		return -ENOMEM;
  
  	while (1) {
  		u32 cap_id;
  
  		cap_id = readl(addr);
  		if (XHCI_EXT_CAPS_ID(cap_id) == XHCI_EXT_CAPS_PROTOCOL)
  			xhci_add_in_port(xhci, num_ports, addr,
  					(u8) XHCI_EXT_PORT_MAJOR(cap_id),
  					cap_count);
  		offset = XHCI_EXT_CAPS_NEXT(cap_id);
  		if (!offset || (xhci->num_usb2_ports + xhci->num_usb3_ports)
  				== num_ports)
  			break;
  		/*
  		 * Once you're into the Extended Capabilities, the offset is
  		 * always relative to the register holding the offset.
  		 */
  		addr += offset;
  	}
  
  	if (xhci->num_usb2_ports == 0 && xhci->num_usb3_ports == 0) {
  		xhci_warn(xhci, "No ports on the roothubs?
  ");
  		return -ENODEV;
  	}
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Found %u USB 2.0 ports and %u USB 3.0 ports.",
  			xhci->num_usb2_ports, xhci->num_usb3_ports);
  
  	/* Place limits on the number of roothub ports so that the hub
  	 * descriptors aren't longer than the USB core will allocate.
  	 */
  	if (xhci->num_usb3_ports > 15) {
  		xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  				"Limiting USB 3.0 roothub ports to 15.");
  		xhci->num_usb3_ports = 15;
  	}
  	if (xhci->num_usb2_ports > USB_MAXCHILDREN) {
  		xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  				"Limiting USB 2.0 roothub ports to %u.",
  				USB_MAXCHILDREN);
  		xhci->num_usb2_ports = USB_MAXCHILDREN;
  	}
  
  	/*
  	 * Note we could have all USB 3.0 ports, or all USB 2.0 ports.
  	 * Not sure how the USB core will handle a hub with no ports...
  	 */
  	if (xhci->num_usb2_ports) {
  		xhci->usb2_ports = kmalloc(sizeof(*xhci->usb2_ports)*
  				xhci->num_usb2_ports, flags);
  		if (!xhci->usb2_ports)
  			return -ENOMEM;
  
  		port_index = 0;
  		for (i = 0; i < num_ports; i++) {
  			if (xhci->port_array[i] == 0x03 ||
  					xhci->port_array[i] == 0 ||
  					xhci->port_array[i] == DUPLICATE_ENTRY)
  				continue;
  
  			xhci->usb2_ports[port_index] =
  				&xhci->op_regs->port_status_base +
  				NUM_PORT_REGS*i;
  			xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  					"USB 2.0 port at index %u, "
  					"addr = %p", i,
  					xhci->usb2_ports[port_index]);
  			port_index++;
  			if (port_index == xhci->num_usb2_ports)
  				break;
  		}
  	}
  	if (xhci->num_usb3_ports) {
  		xhci->usb3_ports = kmalloc(sizeof(*xhci->usb3_ports)*
  				xhci->num_usb3_ports, flags);
  		if (!xhci->usb3_ports)
  			return -ENOMEM;
  
  		port_index = 0;
  		for (i = 0; i < num_ports; i++)
  			if (xhci->port_array[i] == 0x03) {
  				xhci->usb3_ports[port_index] =
  					&xhci->op_regs->port_status_base +
  					NUM_PORT_REGS*i;
  				xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  						"USB 3.0 port at index %u, "
  						"addr = %p", i,
  						xhci->usb3_ports[port_index]);
  				port_index++;
  				if (port_index == xhci->num_usb3_ports)
  					break;
  			}
  	}
  	return 0;
  }
  
  int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
  {
  	dma_addr_t	dma;
  	struct device	*dev = xhci_to_hcd(xhci)->self.controller;
  	unsigned int	val, val2;
  	u64		val_64;
  	struct xhci_segment	*seg;
  	u32 page_size, temp;
  	int i;
  
  	INIT_LIST_HEAD(&xhci->cancel_cmd_list);
  
  	page_size = readl(&xhci->op_regs->page_size);
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Supported page size register = 0x%x", page_size);
  	for (i = 0; i < 16; i++) {
  		if ((0x1 & page_size) != 0)
  			break;
  		page_size = page_size >> 1;
  	}
  	if (i < 16)
  		xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Supported page size of %iK", (1 << (i+12)) / 1024);
  	else
  		xhci_warn(xhci, "WARN: no supported page size
  ");
  	/* Use 4K pages, since that's common and the minimum the HC supports */
  	xhci->page_shift = 12;
  	xhci->page_size = 1 << xhci->page_shift;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"HCD page size set to %iK", xhci->page_size / 1024);
  
  	/*
  	 * Program the Number of Device Slots Enabled field in the CONFIG
  	 * register with the max value of slots the HC can handle.
  	 */
  	val = HCS_MAX_SLOTS(readl(&xhci->cap_regs->hcs_params1));
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// xHC can handle at most %d device slots.", val);
  	val2 = readl(&xhci->op_regs->config_reg);
  	val |= (val2 & ~HCS_SLOTS_MASK);
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// Setting Max device slots reg = 0x%x.", val);
  	writel(val, &xhci->op_regs->config_reg);
  
  	/*
  	 * Section 5.4.8 - doorbell array must be
  	 * "physically contiguous and 64-byte (cache line) aligned".
  	 */
  	xhci->dcbaa = dma_alloc_coherent(dev, sizeof(*xhci->dcbaa), &dma,
  			GFP_KERNEL);
  	if (!xhci->dcbaa)
  		goto fail;
  	memset(xhci->dcbaa, 0, sizeof *(xhci->dcbaa));
  	xhci->dcbaa->dma = dma;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// Device context base array address = 0x%llx (DMA), %p (virt)",
  			(unsigned long long)xhci->dcbaa->dma, xhci->dcbaa);
  	xhci_write_64(xhci, dma, &xhci->op_regs->dcbaa_ptr);
  
  	/*
  	 * Initialize the ring segment pool.  The ring must be a contiguous
  	 * structure comprised of TRBs.  The TRBs must be 16 byte aligned,
  	 * however, the command ring segment needs 64-byte aligned segments,
  	 * so we pick the greater alignment need.
  	 */
  	xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
  			TRB_SEGMENT_SIZE, 64, xhci->page_size);
  
  	/* See Table 46 and Note on Figure 55 */
  	xhci->device_pool = dma_pool_create("xHCI input/output contexts", dev,
  			2112, 64, xhci->page_size);
  	if (!xhci->segment_pool || !xhci->device_pool)
  		goto fail;
  
  	/* Linear stream context arrays don't have any boundary restrictions,
  	 * and only need to be 16-byte aligned.
  	 */
  	xhci->small_streams_pool =
  		dma_pool_create("xHCI 256 byte stream ctx arrays",
  			dev, SMALL_STREAM_ARRAY_SIZE, 16, 0);
  	xhci->medium_streams_pool =
  		dma_pool_create("xHCI 1KB stream ctx arrays",
  			dev, MEDIUM_STREAM_ARRAY_SIZE, 16, 0);
  	/* Any stream context array bigger than MEDIUM_STREAM_ARRAY_SIZE
  	 * will be allocated with dma_alloc_coherent()
  	 */
  
  	if (!xhci->small_streams_pool || !xhci->medium_streams_pool)
  		goto fail;
  
  	/* Set up the command ring to have one segments for now. */
  	xhci->cmd_ring = xhci_ring_alloc(xhci, 1, 1, TYPE_COMMAND, flags);
  	if (!xhci->cmd_ring)
  		goto fail;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Allocated command ring at %p", xhci->cmd_ring);
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "First segment DMA is 0x%llx",
  			(unsigned long long)xhci->cmd_ring->first_seg->dma);
  
  	/* Set the address in the Command Ring Control register */
  	val_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
  	val_64 = (val_64 & (u64) CMD_RING_RSVD_BITS) |
  		(xhci->cmd_ring->first_seg->dma & (u64) ~CMD_RING_RSVD_BITS) |
  		xhci->cmd_ring->cycle_state;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// Setting command ring address to 0x%x", val);
  	xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
  	xhci_dbg_cmd_ptrs(xhci);
  
  	xhci->lpm_command = xhci_alloc_command(xhci, true, true, flags);
  	if (!xhci->lpm_command)
  		goto fail;
  
  	/* Reserve one command ring TRB for disabling LPM.
  	 * Since the USB core grabs the shared usb_bus bandwidth mutex before
  	 * disabling LPM, we only need to reserve one TRB for all devices.
  	 */
  	xhci->cmd_ring_reserved_trbs++;
  
  	val = readl(&xhci->cap_regs->db_off);
  	val &= DBOFF_MASK;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// Doorbell array is located at offset 0x%x"
  			" from cap regs base addr", val);
  	xhci->dba = (void __iomem *) xhci->cap_regs + val;
  	xhci_dbg_regs(xhci);
  	xhci_print_run_regs(xhci);
  	/* Set ir_set to interrupt register set 0 */
  	xhci->ir_set = &xhci->run_regs->ir_set[0];
  
  	/*
  	 * Event ring setup: Allocate a normal ring, but also setup
  	 * the event ring segment table (ERST).  Section 4.9.3.
  	 */
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "// Allocating event ring");
  	xhci->event_ring = xhci_ring_alloc(xhci, ERST_NUM_SEGS, 1, TYPE_EVENT,
  						flags);
  	if (!xhci->event_ring)
  		goto fail;
  	if (xhci_check_trb_in_td_math(xhci, flags) < 0)
  		goto fail;
  
  	xhci->erst.entries = dma_alloc_coherent(dev,
  			sizeof(struct xhci_erst_entry) * ERST_NUM_SEGS, &dma,
  			GFP_KERNEL);
  	if (!xhci->erst.entries)
  		goto fail;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// Allocated event ring segment table at 0x%llx",
  			(unsigned long long)dma);
  
  	memset(xhci->erst.entries, 0, sizeof(struct xhci_erst_entry)*ERST_NUM_SEGS);
  	xhci->erst.num_entries = ERST_NUM_SEGS;
  	xhci->erst.erst_dma_addr = dma;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Set ERST to 0; private num segs = %i, virt addr = %p, dma addr = 0x%llx",
  			xhci->erst.num_entries,
  			xhci->erst.entries,
  			(unsigned long long)xhci->erst.erst_dma_addr);
  
  	/* set ring base address and size for each segment table entry */
  	for (val = 0, seg = xhci->event_ring->first_seg; val < ERST_NUM_SEGS; val++) {
  		struct xhci_erst_entry *entry = &xhci->erst.entries[val];
  		entry->seg_addr = cpu_to_le64(seg->dma);
  		entry->seg_size = cpu_to_le32(TRBS_PER_SEGMENT);
  		entry->rsvd = 0;
  		seg = seg->next;
  	}
  
  	/* set ERST count with the number of entries in the segment table */
  	val = readl(&xhci->ir_set->erst_size);
  	val &= ERST_SIZE_MASK;
  	val |= ERST_NUM_SEGS;
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// Write ERST size = %i to ir_set 0 (some bits preserved)",
  			val);
  	writel(val, &xhci->ir_set->erst_size);
  
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// Set ERST entries to point to event ring.");
  	/* set the segment table base address */
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"// Set ERST base address for ir_set 0 = 0x%llx",
  			(unsigned long long)xhci->erst.erst_dma_addr);
  	val_64 = xhci_read_64(xhci, &xhci->ir_set->erst_base);
  	val_64 &= ERST_PTR_MASK;
  	val_64 |= (xhci->erst.erst_dma_addr & (u64) ~ERST_PTR_MASK);
  	xhci_write_64(xhci, val_64, &xhci->ir_set->erst_base);
  
  	/* Set the event ring dequeue address */
  	xhci_set_hc_event_deq(xhci);
  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
  			"Wrote ERST address to ir_set 0.");
  	xhci_print_ir_set(xhci, 0);
  
  	/*
  	 * XXX: Might need to set the Interrupter Moderation Register to
  	 * something other than the default (~1ms minimum between interrupts).
  	 * See section 5.5.1.2.
  	 */
  	init_completion(&xhci->addr_dev);
  	for (i = 0; i < MAX_HC_SLOTS; ++i)
  		xhci->devs[i] = NULL;
  	for (i = 0; i < USB_MAXCHILDREN; ++i) {
  		xhci->bus_state[0].resume_done[i] = 0;
  		xhci->bus_state[1].resume_done[i] = 0;
  		/* Only the USB 2.0 completions will ever be used. */
  		init_completion(&xhci->bus_state[1].rexit_done[i]);
  	}
  
  	if (scratchpad_alloc(xhci, flags))
  		goto fail;
  	if (xhci_setup_port_arrays(xhci, flags))
  		goto fail;
  
  	/* Enable USB 3.0 device notifications for function remote wake, which
  	 * is necessary for allowing USB 3.0 devices to do remote wakeup from
  	 * U3 (device suspend).
  	 */
  	temp = readl(&xhci->op_regs->dev_notification);
  	temp &= ~DEV_NOTE_MASK;
  	temp |= DEV_NOTE_FWAKE;
  	writel(temp, &xhci->op_regs->dev_notification);
  
  	return 0;
  
  fail:
  	xhci_warn(xhci, "Couldn't initialize memory
  ");
  	xhci_halt(xhci);
  	xhci_reset(xhci);
  	xhci_mem_cleanup(xhci);
  	return -ENOMEM;
  }