diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index dd045173ab79..b17995829514 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -27,6 +27,10 @@ config USB_XHCI_HCD
 	  To compile this driver as a module, choose M here: the
 	  module will be called xhci-hcd.
 
+config USB_XHCI_PLATFORM
+	tristate
+	depends on USB_XHCI_HCD
+
 config USB_XHCI_HCD_DEBUGGING
 	bool "Debugging for the xHCI host controller"
 	depends on USB_XHCI_HCD
diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
index 7ca290fcb070..0982bcc140bd 100644
--- a/drivers/usb/host/Makefile
+++ b/drivers/usb/host/Makefile
@@ -15,6 +15,10 @@ xhci-hcd-y := xhci.o xhci-mem.o
 xhci-hcd-y += xhci-ring.o xhci-hub.o xhci-dbg.o
 xhci-hcd-$(CONFIG_PCI)	+= xhci-pci.o
 
+ifneq ($(CONFIG_USB_XHCI_PLATFORM), )
+	xhci-hcd-y		+= xhci-plat.o
+endif
+
 obj-$(CONFIG_USB_WHCI_HCD)	+= whci/
 
 obj-$(CONFIG_PCI)		+= pci-quirks.o
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 8339d826ce58..cae4c6f2845a 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -34,10 +34,12 @@
  * 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, gfp_t flags)
+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)
@@ -50,6 +52,11 @@ static struct xhci_segment *xhci_segment_alloc(struct xhci_hcd *xhci, gfp_t flag
 	}
 
 	memset(seg->trbs, 0, 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 |= TRB_CYCLE;
+	}
 	seg->dma = dma;
 	seg->next = NULL;
 
@@ -65,6 +72,20 @@ static void xhci_segment_free(struct xhci_hcd *xhci, struct xhci_segment *seg)
 	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.
  *
@@ -73,14 +94,14 @@ static void xhci_segment_free(struct xhci_hcd *xhci, struct xhci_segment *seg)
  * 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, bool link_trbs, bool isoc)
+		struct xhci_segment *next, enum xhci_ring_type type)
 {
 	u32 val;
 
 	if (!prev || !next)
 		return;
 	prev->next = next;
-	if (link_trbs) {
+	if (type != TYPE_EVENT) {
 		prev->trbs[TRBS_PER_SEGMENT-1].link.segment_ptr =
 			cpu_to_le64(next->dma);
 
@@ -91,35 +112,55 @@ static void xhci_link_segments(struct xhci_hcd *xhci, struct xhci_segment *prev,
 		/* 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) ||
-				(isoc && (xhci->quirks & XHCI_AMD_0x96_HOST)))
+				(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)
 {
-	struct xhci_segment *seg;
-	struct xhci_segment *first_seg;
-
 	if (!ring)
 		return;
-	if (ring->first_seg) {
-		first_seg = ring->first_seg;
-		seg = first_seg->next;
-		while (seg != first_seg) {
-			struct xhci_segment *next = seg->next;
-			xhci_segment_free(xhci, seg);
-			seg = next;
-		}
-		xhci_segment_free(xhci, first_seg);
-		ring->first_seg = NULL;
-	}
+
+	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)
+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;
@@ -129,11 +170,53 @@ static void xhci_initialize_ring_info(struct xhci_ring *ring)
 	/* 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 = 1;
+	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) {
+			xhci_free_segments_for_ring(xhci, *first);
+			return -ENOMEM;
+		}
+		xhci_link_segments(xhci, prev, next, type);
+
+		prev = next;
+		num_segs--;
+	}
+	xhci_link_segments(xhci, prev, *first, type);
+	*last = prev;
+
+	return 0;
 }
 
 /**
@@ -144,44 +227,34 @@ static void xhci_initialize_ring_info(struct xhci_ring *ring)
  * 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, bool link_trbs, bool isoc, gfp_t flags)
+		unsigned int num_segs, unsigned int cycle_state,
+		enum xhci_ring_type type, gfp_t flags)
 {
 	struct xhci_ring	*ring;
-	struct xhci_segment	*prev;
+	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;
 
-	ring->first_seg = xhci_segment_alloc(xhci, flags);
-	if (!ring->first_seg)
+	ret = xhci_alloc_segments_for_ring(xhci, &ring->first_seg,
+			&ring->last_seg, num_segs, cycle_state, type, flags);
+	if (ret)
 		goto fail;
-	num_segs--;
 
-	prev = ring->first_seg;
-	while (num_segs > 0) {
-		struct xhci_segment	*next;
-
-		next = xhci_segment_alloc(xhci, flags);
-		if (!next)
-			goto fail;
-		xhci_link_segments(xhci, prev, next, link_trbs, isoc);
-
-		prev = next;
-		num_segs--;
-	}
-	xhci_link_segments(xhci, prev, ring->first_seg, link_trbs, isoc);
-
-	if (link_trbs) {
+	/* Only event ring does not use link TRB */
+	if (type != TYPE_EVENT) {
 		/* See section 4.9.2.1 and 6.4.4.1 */
-		prev->trbs[TRBS_PER_SEGMENT-1].link.control |=
+		ring->last_seg->trbs[TRBS_PER_SEGMENT - 1].link.control |=
 			cpu_to_le32(LINK_TOGGLE);
 	}
-	xhci_initialize_ring_info(ring);
+	xhci_initialize_ring_info(ring, cycle_state);
 	return ring;
 
 fail:
@@ -217,23 +290,64 @@ void xhci_free_or_cache_endpoint_ring(struct xhci_hcd *xhci,
  * pointers to the beginning of the ring.
  */
 static void xhci_reinit_cached_ring(struct xhci_hcd *xhci,
-		struct xhci_ring *ring, bool isoc)
+			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 |= TRB_CYCLE;
+		}
 		/* All endpoint rings have link TRBs */
-		xhci_link_segments(xhci, seg, seg->next, 1, isoc);
+		xhci_link_segments(xhci, seg, seg->next, type);
 		seg = seg->next;
 	} while (seg != ring->first_seg);
-	xhci_initialize_ring_info(ring);
+	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(xhci, "ring expansion succeed, now has %d segments\n",
+			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,
@@ -528,7 +642,7 @@ struct xhci_stream_info *xhci_alloc_stream_info(struct xhci_hcd *xhci,
 	 */
 	for (cur_stream = 1; cur_stream < num_streams; cur_stream++) {
 		stream_info->stream_rings[cur_stream] =
-			xhci_ring_alloc(xhci, 1, true, false, mem_flags);
+			xhci_ring_alloc(xhci, 2, 1, TYPE_STREAM, mem_flags);
 		cur_ring = stream_info->stream_rings[cur_stream];
 		if (!cur_ring)
 			goto cleanup_rings;
@@ -862,7 +976,7 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
 	}
 
 	/* Allocate endpoint 0 ring */
-	dev->eps[0].ring = xhci_ring_alloc(xhci, 1, true, false, flags);
+	dev->eps[0].ring = xhci_ring_alloc(xhci, 2, 1, TYPE_CTRL, flags);
 	if (!dev->eps[0].ring)
 		goto fail;
 
@@ -1300,24 +1414,16 @@ int xhci_endpoint_init(struct xhci_hcd *xhci,
 	struct xhci_ring *ep_ring;
 	unsigned int max_packet;
 	unsigned int max_burst;
+	enum xhci_ring_type type;
 	u32 max_esit_payload;
 
 	ep_index = xhci_get_endpoint_index(&ep->desc);
 	ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);
 
+	type = usb_endpoint_type(&ep->desc);
 	/* Set up the endpoint ring */
-	/*
-	 * Isochronous endpoint ring needs bigger size because one isoc URB
-	 * carries multiple packets and it will insert multiple tds to the
-	 * ring.
-	 * This should be replaced with dynamic ring resizing in the future.
-	 */
-	if (usb_endpoint_xfer_isoc(&ep->desc))
-		virt_dev->eps[ep_index].new_ring =
-			xhci_ring_alloc(xhci, 8, true, true, mem_flags);
-	else
-		virt_dev->eps[ep_index].new_ring =
-			xhci_ring_alloc(xhci, 1, true, false, mem_flags);
+	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)
@@ -1327,7 +1433,7 @@ int xhci_endpoint_init(struct xhci_hcd *xhci,
 		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,
-			usb_endpoint_xfer_isoc(&ep->desc) ? true : false);
+					1, type);
 	}
 	virt_dev->eps[ep_index].skip = false;
 	ep_ring = virt_dev->eps[ep_index].new_ring;
@@ -2235,7 +2341,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 		goto fail;
 
 	/* Set up the command ring to have one segments for now. */
-	xhci->cmd_ring = xhci_ring_alloc(xhci, 1, true, false, flags);
+	xhci->cmd_ring = xhci_ring_alloc(xhci, 1, 1, TYPE_COMMAND, flags);
 	if (!xhci->cmd_ring)
 		goto fail;
 	xhci_dbg(xhci, "Allocated command ring at %p\n", xhci->cmd_ring);
@@ -2266,7 +2372,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	 * the event ring segment table (ERST).  Section 4.9.3.
 	 */
 	xhci_dbg(xhci, "// Allocating event ring\n");
-	xhci->event_ring = xhci_ring_alloc(xhci, ERST_NUM_SEGS, false, false,
+	xhci->event_ring = xhci_ring_alloc(xhci, ERST_NUM_SEGS, 1, TYPE_EVENT,
 						flags);
 	if (!xhci->event_ring)
 		goto fail;
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
new file mode 100644
index 000000000000..689bc18b051d
--- /dev/null
+++ b/drivers/usb/host/xhci-plat.c
@@ -0,0 +1,205 @@
+/*
+ * xhci-plat.c - xHCI host controller driver platform Bus Glue.
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
+ * Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+ *
+ * A lot of code borrowed from the Linux xHCI 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.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "xhci.h"
+
+static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
+{
+	/*
+	 * As of now platform drivers don't provide MSI support so we ensure
+	 * here that the generic code does not try to make a pci_dev from our
+	 * dev struct in order to setup MSI
+	 */
+	xhci->quirks |= XHCI_BROKEN_MSI;
+}
+
+/* called during probe() after chip reset completes */
+static int xhci_plat_setup(struct usb_hcd *hcd)
+{
+	return xhci_gen_setup(hcd, xhci_plat_quirks);
+}
+
+static const struct hc_driver xhci_plat_xhci_driver = {
+	.description =		"xhci-hcd",
+	.product_desc =		"xHCI Host Controller",
+	.hcd_priv_size =	sizeof(struct xhci_hcd *),
+
+	/*
+	 * generic hardware linkage
+	 */
+	.irq =			xhci_irq,
+	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED,
+
+	/*
+	 * basic lifecycle operations
+	 */
+	.reset =		xhci_plat_setup,
+	.start =		xhci_run,
+	.stop =			xhci_stop,
+	.shutdown =		xhci_shutdown,
+
+	/*
+	 * managing i/o requests and associated device resources
+	 */
+	.urb_enqueue =		xhci_urb_enqueue,
+	.urb_dequeue =		xhci_urb_dequeue,
+	.alloc_dev =		xhci_alloc_dev,
+	.free_dev =		xhci_free_dev,
+	.alloc_streams =	xhci_alloc_streams,
+	.free_streams =		xhci_free_streams,
+	.add_endpoint =		xhci_add_endpoint,
+	.drop_endpoint =	xhci_drop_endpoint,
+	.endpoint_reset =	xhci_endpoint_reset,
+	.check_bandwidth =	xhci_check_bandwidth,
+	.reset_bandwidth =	xhci_reset_bandwidth,
+	.address_device =	xhci_address_device,
+	.update_hub_device =	xhci_update_hub_device,
+	.reset_device =		xhci_discover_or_reset_device,
+
+	/*
+	 * scheduling support
+	 */
+	.get_frame_number =	xhci_get_frame,
+
+	/* Root hub support */
+	.hub_control =		xhci_hub_control,
+	.hub_status_data =	xhci_hub_status_data,
+	.bus_suspend =		xhci_bus_suspend,
+	.bus_resume =		xhci_bus_resume,
+};
+
+static int xhci_plat_probe(struct platform_device *pdev)
+{
+	const struct hc_driver	*driver;
+	struct xhci_hcd		*xhci;
+	struct resource         *res;
+	struct usb_hcd		*hcd;
+	int			ret;
+	int			irq;
+
+	if (usb_disabled())
+		return -ENODEV;
+
+	driver = &xhci_plat_xhci_driver;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return -ENODEV;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
+	if (!hcd)
+		return -ENOMEM;
+
+	hcd->rsrc_start = res->start;
+	hcd->rsrc_len = resource_size(res);
+
+	if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len,
+				driver->description)) {
+		dev_dbg(&pdev->dev, "controller already in use\n");
+		ret = -EBUSY;
+		goto put_hcd;
+	}
+
+	hcd->regs = ioremap(hcd->rsrc_start, hcd->rsrc_len);
+	if (!hcd->regs) {
+		dev_dbg(&pdev->dev, "error mapping memory\n");
+		ret = -EFAULT;
+		goto release_mem_region;
+	}
+
+	ret = usb_add_hcd(hcd, irq, IRQF_SHARED);
+	if (ret)
+		goto unmap_registers;
+
+	/* USB 2.0 roothub is stored in the platform_device now. */
+	hcd = dev_get_drvdata(&pdev->dev);
+	xhci = hcd_to_xhci(hcd);
+	xhci->shared_hcd = usb_create_shared_hcd(driver, &pdev->dev,
+			dev_name(&pdev->dev), hcd);
+	if (!xhci->shared_hcd) {
+		ret = -ENOMEM;
+		goto dealloc_usb2_hcd;
+	}
+
+	/*
+	 * Set the xHCI pointer before xhci_plat_setup() (aka hcd_driver.reset)
+	 * is called by usb_add_hcd().
+	 */
+	*((struct xhci_hcd **) xhci->shared_hcd->hcd_priv) = xhci;
+
+	ret = usb_add_hcd(xhci->shared_hcd, irq, IRQF_SHARED);
+	if (ret)
+		goto put_usb3_hcd;
+
+	return 0;
+
+put_usb3_hcd:
+	usb_put_hcd(xhci->shared_hcd);
+
+dealloc_usb2_hcd:
+	usb_remove_hcd(hcd);
+
+unmap_registers:
+	iounmap(hcd->regs);
+
+release_mem_region:
+	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
+
+put_hcd:
+	usb_put_hcd(hcd);
+
+	return ret;
+}
+
+static int xhci_plat_remove(struct platform_device *dev)
+{
+	struct usb_hcd	*hcd = platform_get_drvdata(dev);
+	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
+
+	usb_remove_hcd(xhci->shared_hcd);
+	usb_put_hcd(xhci->shared_hcd);
+
+	usb_remove_hcd(hcd);
+	iounmap(hcd->regs);
+	usb_put_hcd(hcd);
+	kfree(xhci);
+
+	return 0;
+}
+
+static struct platform_driver usb_xhci_driver = {
+	.probe	= xhci_plat_probe,
+	.remove	= xhci_plat_remove,
+	.driver	= {
+		.name = "xhci-hcd",
+	},
+};
+MODULE_ALIAS("platform:xhci-hcd");
+
+int xhci_register_plat(void)
+{
+	return platform_driver_register(&usb_xhci_driver);
+}
+
+void xhci_unregister_plat(void)
+{
+	platform_driver_unregister(&usb_xhci_driver);
+}
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9e71f7c46a85..6bd9d53062eb 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -143,17 +143,25 @@ static void next_trb(struct xhci_hcd *xhci,
  * See Cycle bit rules. SW is the consumer for the event ring only.
  * Don't make a ring full of link TRBs.  That would be dumb and this would loop.
  */
-static void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring, bool consumer)
+static void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring)
 {
-	union xhci_trb *next = ++(ring->dequeue);
+	union xhci_trb *next;
 	unsigned long long addr;
 
 	ring->deq_updates++;
+
+	/* If this is not event ring, there is one more usable TRB */
+	if (ring->type != TYPE_EVENT &&
+			!last_trb(xhci, ring, ring->deq_seg, ring->dequeue))
+		ring->num_trbs_free++;
+	next = ++(ring->dequeue);
+
 	/* Update the dequeue pointer further if that was a link TRB or we're at
 	 * the end of an event ring segment (which doesn't have link TRBS)
 	 */
 	while (last_trb(xhci, ring, ring->deq_seg, next)) {
-		if (consumer && last_trb_on_last_seg(xhci, ring, ring->deq_seg, next)) {
+		if (ring->type == TYPE_EVENT &&	last_trb_on_last_seg(xhci,
+				ring, ring->deq_seg, next)) {
 			ring->cycle_state = (ring->cycle_state ? 0 : 1);
 		}
 		ring->deq_seg = ring->deq_seg->next;
@@ -181,13 +189,17 @@ static void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring, bool consumer
  *			prepare_transfer()?
  */
 static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring,
-		bool consumer, bool more_trbs_coming, bool isoc)
+			bool more_trbs_coming)
 {
 	u32 chain;
 	union xhci_trb *next;
 	unsigned long long addr;
 
 	chain = le32_to_cpu(ring->enqueue->generic.field[3]) & TRB_CHAIN;
+	/* If this is not event ring, there is one less usable TRB */
+	if (ring->type != TYPE_EVENT &&
+			!last_trb(xhci, ring, ring->enq_seg, ring->enqueue))
+		ring->num_trbs_free--;
 	next = ++(ring->enqueue);
 
 	ring->enq_updates++;
@@ -195,35 +207,35 @@ static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring,
 	 * the end of an event ring segment (which doesn't have link TRBS)
 	 */
 	while (last_trb(xhci, ring, ring->enq_seg, next)) {
-		if (!consumer) {
-			if (ring != xhci->event_ring) {
-				/*
-				 * 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 (ring->type != TYPE_EVENT) {
+			/*
+			 * 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 (!(isoc && (xhci->quirks & XHCI_AMD_0x96_HOST))
+			/* 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);
+				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 (last_trb_on_last_seg(xhci, ring, ring->enq_seg, next)) {
 				ring->cycle_state = (ring->cycle_state ? 0 : 1);
@@ -237,55 +249,23 @@ static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring,
 }
 
 /*
- * Check to see if there's room to enqueue num_trbs on the ring.  See rules
- * above.
- * FIXME: this would be simpler and faster if we just kept track of the number
- * of free TRBs in a ring.
+ * Check to see if there's room to enqueue num_trbs on the ring and make sure
+ * enqueue pointer will not advance into dequeue segment. See rules above.
  */
-static int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring,
+static inline int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring,
 		unsigned int num_trbs)
 {
-	int i;
-	union xhci_trb *enq = ring->enqueue;
-	struct xhci_segment *enq_seg = ring->enq_seg;
-	struct xhci_segment *cur_seg;
-	unsigned int left_on_ring;
+	int num_trbs_in_deq_seg;
 
-	/* If we are currently pointing to a link TRB, advance the
-	 * enqueue pointer before checking for space */
-	while (last_trb(xhci, ring, enq_seg, enq)) {
-		enq_seg = enq_seg->next;
-		enq = enq_seg->trbs;
-	}
+	if (ring->num_trbs_free < num_trbs)
+		return 0;
 
-	/* Check if ring is empty */
-	if (enq == ring->dequeue) {
-		/* Can't use link trbs */
-		left_on_ring = TRBS_PER_SEGMENT - 1;
-		for (cur_seg = enq_seg->next; cur_seg != enq_seg;
-				cur_seg = cur_seg->next)
-			left_on_ring += TRBS_PER_SEGMENT - 1;
-
-		/* Always need one TRB free in the ring. */
-		left_on_ring -= 1;
-		if (num_trbs > left_on_ring) {
-			xhci_warn(xhci, "Not enough room on ring; "
-					"need %u TRBs, %u TRBs left\n",
-					num_trbs, left_on_ring);
+	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;
-	}
-	/* Make sure there's an extra empty TRB available */
-	for (i = 0; i <= num_trbs; ++i) {
-		if (enq == ring->dequeue)
-			return 0;
-		enq++;
-		while (last_trb(xhci, ring, enq_seg, enq)) {
-			enq_seg = enq_seg->next;
-			enq = enq_seg->trbs;
-		}
 	}
+
 	return 1;
 }
 
@@ -892,6 +872,43 @@ void xhci_stop_endpoint_command_watchdog(unsigned long arg)
 	xhci_dbg(xhci, "xHCI host controller is dead.\n");
 }
 
+
+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;
+
+	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 (last_trb(xhci, ep_ring, ep_ring->deq_seg,
+				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
@@ -973,8 +990,8 @@ static void handle_set_deq_completion(struct xhci_hcd *xhci,
 			/* Update the ring's dequeue segment and dequeue pointer
 			 * to reflect the new position.
 			 */
-			ep_ring->deq_seg = dev->eps[ep_index].queued_deq_seg;
-			ep_ring->dequeue = dev->eps[ep_index].queued_deq_ptr;
+			update_ring_for_set_deq_completion(xhci, dev,
+				ep_ring, ep_index);
 		} else {
 			xhci_warn(xhci, "Mismatch between completed Set TR Deq "
 					"Ptr command & xHCI internal state.\n");
@@ -1185,7 +1202,7 @@ bandwidth_change:
 		xhci->error_bitmask |= 1 << 6;
 		break;
 	}
-	inc_deq(xhci, xhci->cmd_ring, false);
+	inc_deq(xhci, xhci->cmd_ring);
 }
 
 static void handle_vendor_event(struct xhci_hcd *xhci,
@@ -1398,7 +1415,7 @@ static void handle_port_status(struct xhci_hcd *xhci,
 
 cleanup:
 	/* Update event ring dequeue pointer before dropping the lock */
-	inc_deq(xhci, xhci->event_ring, true);
+	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
@@ -1593,8 +1610,8 @@ static int finish_td(struct xhci_hcd *xhci, struct xhci_td *td,
 		} else {
 			/* Update ring dequeue pointer */
 			while (ep_ring->dequeue != td->last_trb)
-				inc_deq(xhci, ep_ring, false);
-			inc_deq(xhci, ep_ring, false);
+				inc_deq(xhci, ep_ring);
+			inc_deq(xhci, ep_ring);
 		}
 
 td_cleanup:
@@ -1842,8 +1859,8 @@ static int skip_isoc_td(struct xhci_hcd *xhci, struct xhci_td *td,
 
 	/* Update ring dequeue pointer */
 	while (ep_ring->dequeue != td->last_trb)
-		inc_deq(xhci, ep_ring, false);
-	inc_deq(xhci, ep_ring, false);
+		inc_deq(xhci, ep_ring);
+	inc_deq(xhci, ep_ring);
 
 	return finish_td(xhci, td, NULL, event, ep, status, true);
 }
@@ -2230,7 +2247,7 @@ cleanup:
 		 * Will roll back to continue process missed tds.
 		 */
 		if (trb_comp_code == COMP_MISSED_INT || !ep->skip) {
-			inc_deq(xhci, xhci->event_ring, true);
+			inc_deq(xhci, xhci->event_ring);
 		}
 
 		if (ret) {
@@ -2345,7 +2362,7 @@ static int xhci_handle_event(struct xhci_hcd *xhci)
 
 	if (update_ptrs)
 		/* Update SW event ring dequeue pointer */
-		inc_deq(xhci, xhci->event_ring, true);
+		inc_deq(xhci, xhci->event_ring);
 
 	/* Are there more items on the event ring?  Caller will call us again to
 	 * check.
@@ -2461,7 +2478,7 @@ irqreturn_t xhci_msi_irq(int irq, struct usb_hcd *hcd)
  *			prepare_transfer()?
  */
 static void queue_trb(struct xhci_hcd *xhci, struct xhci_ring *ring,
-		bool consumer, bool more_trbs_coming, bool isoc,
+		bool more_trbs_coming,
 		u32 field1, u32 field2, u32 field3, u32 field4)
 {
 	struct xhci_generic_trb *trb;
@@ -2471,7 +2488,7 @@ static void queue_trb(struct xhci_hcd *xhci, struct xhci_ring *ring,
 	trb->field[1] = cpu_to_le32(field2);
 	trb->field[2] = cpu_to_le32(field3);
 	trb->field[3] = cpu_to_le32(field4);
-	inc_enq(xhci, ring, consumer, more_trbs_coming, isoc);
+	inc_enq(xhci, ring, more_trbs_coming);
 }
 
 /*
@@ -2479,8 +2496,10 @@ static void queue_trb(struct xhci_hcd *xhci, struct xhci_ring *ring,
  * 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, bool isoc, gfp_t mem_flags)
+		u32 ep_state, unsigned int num_trbs, gfp_t mem_flags)
 {
+	unsigned int num_trbs_needed;
+
 	/* Make sure the endpoint has been added to xHC schedule */
 	switch (ep_state) {
 	case EP_STATE_DISABLED:
@@ -2508,11 +2527,25 @@ static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
 		 */
 		return -EINVAL;
 	}
-	if (!room_on_ring(xhci, ep_ring, num_trbs)) {
-		/* FIXME allocate more room */
-		xhci_err(xhci, "ERROR no room on ep ring\n");
-		return -ENOMEM;
-	}
+
+	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(xhci, "ERROR no room on ep ring, "
+					"try ring expansion\n");
+		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;
+		}
+	};
 
 	if (enqueue_is_link_trb(ep_ring)) {
 		struct xhci_ring *ring = ep_ring;
@@ -2524,8 +2557,9 @@ static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
 			/* 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) && !(isoc &&
-					(xhci->quirks & XHCI_AMD_0x96_HOST)))
+			if (!xhci_link_trb_quirk(xhci) &&
+					!(ring->type == TYPE_ISOC &&
+					 (xhci->quirks & XHCI_AMD_0x96_HOST)))
 				next->link.control &= cpu_to_le32(~TRB_CHAIN);
 			else
 				next->link.control |= cpu_to_le32(TRB_CHAIN);
@@ -2553,7 +2587,6 @@ static int prepare_transfer(struct xhci_hcd *xhci,
 		unsigned int num_trbs,
 		struct urb *urb,
 		unsigned int td_index,
-		bool isoc,
 		gfp_t mem_flags)
 {
 	int ret;
@@ -2571,7 +2604,7 @@ static int prepare_transfer(struct xhci_hcd *xhci,
 
 	ret = prepare_ring(xhci, ep_ring,
 			   le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK,
-			   num_trbs, isoc, mem_flags);
+			   num_trbs, mem_flags);
 	if (ret)
 		return ret;
 
@@ -2781,7 +2814,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 
 	trb_buff_len = prepare_transfer(xhci, xhci->devs[slot_id],
 			ep_index, urb->stream_id,
-			num_trbs, urb, 0, false, mem_flags);
+			num_trbs, urb, 0, mem_flags);
 	if (trb_buff_len < 0)
 		return trb_buff_len;
 
@@ -2869,7 +2902,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 			more_trbs_coming = true;
 		else
 			more_trbs_coming = false;
-		queue_trb(xhci, ep_ring, false, more_trbs_coming, false,
+		queue_trb(xhci, ep_ring, more_trbs_coming,
 				lower_32_bits(addr),
 				upper_32_bits(addr),
 				length_field,
@@ -2951,7 +2984,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 
 	ret = prepare_transfer(xhci, xhci->devs[slot_id],
 			ep_index, urb->stream_id,
-			num_trbs, urb, 0, false, mem_flags);
+			num_trbs, urb, 0, mem_flags);
 	if (ret < 0)
 		return ret;
 
@@ -3023,7 +3056,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 			more_trbs_coming = true;
 		else
 			more_trbs_coming = false;
-		queue_trb(xhci, ep_ring, false, more_trbs_coming, false,
+		queue_trb(xhci, ep_ring, more_trbs_coming,
 				lower_32_bits(addr),
 				upper_32_bits(addr),
 				length_field,
@@ -3080,7 +3113,7 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 		num_trbs++;
 	ret = prepare_transfer(xhci, xhci->devs[slot_id],
 			ep_index, urb->stream_id,
-			num_trbs, urb, 0, false, mem_flags);
+			num_trbs, urb, 0, mem_flags);
 	if (ret < 0)
 		return ret;
 
@@ -3113,7 +3146,7 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 		}
 	}
 
-	queue_trb(xhci, ep_ring, false, true, false,
+	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),
@@ -3133,7 +3166,7 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 	if (urb->transfer_buffer_length > 0) {
 		if (setup->bRequestType & USB_DIR_IN)
 			field |= TRB_DIR_IN;
-		queue_trb(xhci, ep_ring, false, true, false,
+		queue_trb(xhci, ep_ring, true,
 				lower_32_bits(urb->transfer_dma),
 				upper_32_bits(urb->transfer_dma),
 				length_field,
@@ -3149,7 +3182,7 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 		field = 0;
 	else
 		field = TRB_DIR_IN;
-	queue_trb(xhci, ep_ring, false, false, false,
+	queue_trb(xhci, ep_ring, false,
 			0,
 			0,
 			TRB_INTR_TARGET(0),
@@ -3289,8 +3322,7 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 		trbs_per_td = count_isoc_trbs_needed(xhci, urb, i);
 
 		ret = prepare_transfer(xhci, xhci->devs[slot_id], ep_index,
-				urb->stream_id, trbs_per_td, urb, i, true,
-				mem_flags);
+				urb->stream_id, trbs_per_td, urb, i, mem_flags);
 		if (ret < 0) {
 			if (i == 0)
 				return ret;
@@ -3360,7 +3392,7 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 				remainder |
 				TRB_INTR_TARGET(0);
 
-			queue_trb(xhci, ep_ring, false, more_trbs_coming, true,
+			queue_trb(xhci, ep_ring, more_trbs_coming,
 				lower_32_bits(addr),
 				upper_32_bits(addr),
 				length_field,
@@ -3407,6 +3439,7 @@ cleanup:
 	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;
 }
@@ -3443,7 +3476,7 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci, gfp_t mem_flags,
 	 * Do not insert any td of the urb to the ring if the check failed.
 	 */
 	ret = prepare_ring(xhci, ep_ring, le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK,
-			   num_trbs, true, mem_flags);
+			   num_trbs, mem_flags);
 	if (ret)
 		return ret;
 
@@ -3479,6 +3512,8 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci, gfp_t mem_flags,
 				urb->dev->speed == USB_SPEED_FULL)
 			urb->interval /= 8;
 	}
+	ep_ring->num_trbs_free_temp = ep_ring->num_trbs_free;
+
 	return xhci_queue_isoc_tx(xhci, GFP_ATOMIC, urb, slot_id, ep_index);
 }
 
@@ -3502,7 +3537,7 @@ static int queue_command(struct xhci_hcd *xhci, u32 field1, u32 field2,
 		reserved_trbs++;
 
 	ret = prepare_ring(xhci, xhci->cmd_ring, EP_STATE_RUNNING,
-			reserved_trbs, false, GFP_ATOMIC);
+			reserved_trbs, GFP_ATOMIC);
 	if (ret < 0) {
 		xhci_err(xhci, "ERR: No room for command on command ring\n");
 		if (command_must_succeed)
@@ -3510,8 +3545,8 @@ static int queue_command(struct xhci_hcd *xhci, u32 field1, u32 field2,
 					"unfailable commands failed.\n");
 		return ret;
 	}
-	queue_trb(xhci, xhci->cmd_ring, false, false, false, field1, field2,
-			field3,	field4 | xhci->cmd_ring->cycle_state);
+	queue_trb(xhci, xhci->cmd_ring, false, field1, field2, field3,
+			field4 | xhci->cmd_ring->cycle_state);
 	return 0;
 }
 
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index a629ad860329..e1963d4a430f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -729,6 +729,7 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci)
 	ring->enq_seg = ring->deq_seg;
 	ring->enqueue = ring->dequeue;
 
+	ring->num_trbs_free = ring->num_segs * (TRBS_PER_SEGMENT - 1) - 1;
 	/*
 	 * Ring is now zeroed, so the HW should look for change of ownership
 	 * when the cycle bit is set to 1.
@@ -3614,26 +3615,38 @@ static int xhci_besl_encoding[16] = {125, 150, 200, 300, 400, 500, 1000, 2000,
 	3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000};
 
 /* Calculate HIRD/BESL for USB2 PORTPMSC*/
-static int xhci_calculate_hird_besl(int u2del, bool use_besl)
+static int xhci_calculate_hird_besl(struct xhci_hcd *xhci,
+					struct usb_device *udev)
 {
-	int hird;
+	int u2del, besl, besl_host;
+	int besl_device = 0;
+	u32 field;
 
-	if (use_besl) {
-		for (hird = 0; hird < 16; hird++) {
-			if (xhci_besl_encoding[hird] >= u2del)
+	u2del = HCS_U2_LATENCY(xhci->hcs_params3);
+	field = le32_to_cpu(udev->bos->ext_cap->bmAttributes);
+
+	if (field & USB_BESL_SUPPORT) {
+		for (besl_host = 0; besl_host < 16; besl_host++) {
+			if (xhci_besl_encoding[besl_host] >= u2del)
 				break;
 		}
+		/* Use baseline BESL value as default */
+		if (field & USB_BESL_BASELINE_VALID)
+			besl_device = USB_GET_BESL_BASELINE(field);
+		else if (field & USB_BESL_DEEP_VALID)
+			besl_device = USB_GET_BESL_DEEP(field);
 	} else {
 		if (u2del <= 50)
-			hird = 0;
+			besl_host = 0;
 		else
-			hird = (u2del - 51) / 75 + 1;
-
-		if (hird > 15)
-			hird = 15;
+			besl_host = (u2del - 51) / 75 + 1;
 	}
 
-	return hird;
+	besl = besl_host + besl_device;
+	if (besl > 15)
+		besl = 15;
+
+	return besl;
 }
 
 static int xhci_usb2_software_lpm_test(struct usb_hcd *hcd,
@@ -3646,7 +3659,7 @@ static int xhci_usb2_software_lpm_test(struct usb_hcd *hcd,
 	u32		temp, dev_id;
 	unsigned int	port_num;
 	unsigned long	flags;
-	int		u2del, hird;
+	int		hird;
 	int		ret;
 
 	if (hcd->speed == HCD_USB3 || !xhci->sw_lpm_support ||
@@ -3692,12 +3705,7 @@ static int xhci_usb2_software_lpm_test(struct usb_hcd *hcd,
 	 * HIRD or BESL shoule be used. See USB2.0 LPM errata.
 	 */
 	pm_addr = port_array[port_num] + 1;
-	u2del = HCS_U2_LATENCY(xhci->hcs_params3);
-	if (le32_to_cpu(udev->bos->ext_cap->bmAttributes) & (1 << 2))
-		hird = xhci_calculate_hird_besl(u2del, 1);
-	else
-		hird = xhci_calculate_hird_besl(u2del, 0);
-
+	hird = xhci_calculate_hird_besl(xhci, udev);
 	temp = PORT_L1DS(udev->slot_id) | PORT_HIRD(hird);
 	xhci_writel(xhci, temp, pm_addr);
 
@@ -3776,7 +3784,7 @@ int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
 	u32		temp;
 	unsigned int	port_num;
 	unsigned long	flags;
-	int		u2del, hird;
+	int		hird;
 
 	if (hcd->speed == HCD_USB3 || !xhci->hw_lpm_support ||
 			!udev->lpm_capable)
@@ -3799,11 +3807,7 @@ int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
 	xhci_dbg(xhci, "%s port %d USB2 hardware LPM\n",
 			enable ? "enable" : "disable", port_num);
 
-	u2del = HCS_U2_LATENCY(xhci->hcs_params3);
-	if (le32_to_cpu(udev->bos->ext_cap->bmAttributes) & (1 << 2))
-		hird = xhci_calculate_hird_besl(u2del, 1);
-	else
-		hird = xhci_calculate_hird_besl(u2del, 0);
+	hird = xhci_calculate_hird_besl(xhci, udev);
 
 	if (enable) {
 		temp &= ~PORT_HIRD_MASK;
@@ -3964,7 +3968,8 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 	int			retval;
 	u32			temp;
 
-	hcd->self.sg_tablesize = TRBS_PER_SEGMENT - 2;
+	/* Accept arbitrarily long scatter-gather lists */
+	hcd->self.sg_tablesize = ~0;
 
 	if (usb_hcd_is_primary_hcd(hcd)) {
 		xhci = kzalloc(sizeof(struct xhci_hcd), GFP_KERNEL);
@@ -4059,6 +4064,11 @@ static int __init xhci_hcd_init(void)
 		printk(KERN_DEBUG "Problem registering PCI driver.");
 		return retval;
 	}
+	retval = xhci_register_plat();
+	if (retval < 0) {
+		printk(KERN_DEBUG "Problem registering platform driver.");
+		goto unreg_pci;
+	}
 	/*
 	 * Check the compiler generated sizes of structures that must be laid
 	 * out in specific ways for hardware access.
@@ -4078,11 +4088,15 @@ static int __init xhci_hcd_init(void)
 	BUILD_BUG_ON(sizeof(struct xhci_run_regs) != (8+8*128)*32/8);
 	BUILD_BUG_ON(sizeof(struct xhci_doorbell_array) != 256*32/8);
 	return 0;
+unreg_pci:
+	xhci_unregister_pci();
+	return retval;
 }
 module_init(xhci_hcd_init);
 
 static void __exit xhci_hcd_cleanup(void)
 {
 	xhci_unregister_pci();
+	xhci_unregister_plat();
 }
 module_exit(xhci_hcd_cleanup);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 0f4936956103..91074fdab3eb 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1223,10 +1223,7 @@ union xhci_trb {
 /* Allow two commands + a link TRB, along with any reserved command TRBs */
 #define MAX_RSVD_CMD_TRBS	(TRBS_PER_SEGMENT - 3)
 #define SEGMENT_SIZE		(TRBS_PER_SEGMENT*16)
-/* SEGMENT_SHIFT should be log2(SEGMENT_SIZE).
- * Change this if you change TRBS_PER_SEGMENT!
- */
-#define SEGMENT_SHIFT		10
+#define SEGMENT_SHIFT		(__ffs(SEGMENT_SIZE))
 /* TRB buffer pointers can't cross 64KB boundaries */
 #define TRB_MAX_BUFF_SHIFT		16
 #define TRB_MAX_BUFF_SIZE	(1 << TRB_MAX_BUFF_SHIFT)
@@ -1253,8 +1250,19 @@ struct xhci_dequeue_state {
 	int new_cycle_state;
 };
 
+enum xhci_ring_type {
+	TYPE_CTRL = 0,
+	TYPE_ISOC,
+	TYPE_BULK,
+	TYPE_INTR,
+	TYPE_STREAM,
+	TYPE_COMMAND,
+	TYPE_EVENT,
+};
+
 struct xhci_ring {
 	struct xhci_segment	*first_seg;
+	struct xhci_segment	*last_seg;
 	union  xhci_trb		*enqueue;
 	struct xhci_segment	*enq_seg;
 	unsigned int		enq_updates;
@@ -1269,6 +1277,10 @@ struct xhci_ring {
 	 */
 	u32			cycle_state;
 	unsigned int		stream_id;
+	unsigned int		num_segs;
+	unsigned int		num_trbs_free;
+	unsigned int		num_trbs_free_temp;
+	enum xhci_ring_type	type;
 	bool			last_td_was_short;
 };
 
@@ -1610,6 +1622,8 @@ 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);
 void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring);
+int xhci_ring_expansion(struct xhci_hcd *xhci, struct xhci_ring *ring,
+				unsigned int num_trbs, gfp_t flags);
 void xhci_free_or_cache_endpoint_ring(struct xhci_hcd *xhci,
 		struct xhci_virt_device *virt_dev,
 		unsigned int ep_index);
@@ -1649,6 +1663,17 @@ static inline int xhci_register_pci(void) { return 0; }
 static inline void xhci_unregister_pci(void) {}
 #endif
 
+#if defined(CONFIG_USB_XHCI_PLATFORM) \
+	|| defined(CONFIG_USB_XHCI_PLATFORM_MODULE)
+int xhci_register_plat(void);
+void xhci_unregister_plat(void);
+#else
+static inline int xhci_register_plat(void)
+{ return 0; }
+static inline void xhci_unregister_plat(void)
+{  }
+#endif
+
 /* xHCI host controller glue */
 typedef void (*xhci_get_quirks_t)(struct device *, struct xhci_hcd *);
 void xhci_quiesce(struct xhci_hcd *xhci);
diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h
index 3b6f628880f8..af21f3115919 100644
--- a/include/linux/usb/ch9.h
+++ b/include/linux/usb/ch9.h
@@ -789,6 +789,11 @@ struct usb_ext_cap_descriptor {		/* Link Power Management */
 	__u8  bDevCapabilityType;
 	__le32 bmAttributes;
 #define USB_LPM_SUPPORT			(1 << 1)	/* supports LPM */
+#define USB_BESL_SUPPORT		(1 << 2)	/* supports BESL */
+#define USB_BESL_BASELINE_VALID		(1 << 3)	/* Baseline BESL valid*/
+#define USB_BESL_DEEP_VALID		(1 << 4)	/* Deep BESL valid */
+#define USB_GET_BESL_BASELINE(p)	(((p) & (0xf << 8)) >> 8)
+#define USB_GET_BESL_DEEP(p)		(((p) & (0xf << 12)) >> 12)
 } __attribute__((packed));
 
 #define USB_DT_USB_EXT_CAP_SIZE	7