USB: xhci: Represent 64-bit addresses with one u64.

There are several xHCI data structures that use two 32-bit fields to
represent a 64-bit address.  Since some architectures don't support 64-bit
PCI writes, the fields need to be written in two 32-bit writes.  The xHCI
specification says that if a platform is incapable of generating 64-bit
writes, software must write the low 32-bits first, then the high 32-bits.
Hardware that supports 64-bit addressing will wait for the high 32-bit
write before reading the revised value, and hardware that only supports
32-bit writes will ignore the high 32-bit write.

Previous xHCI code represented 64-bit addresses with two u32 values.  This
lead to buggy code that would write the 32-bits in the wrong order, or
forget to write the upper 32-bits.  Change the two u32s to one u64 and
create a function call to write all 64-bit addresses in the proper order.
This new function could be modified in the future if all platforms support
64-bit writes.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

5 files changed, 137 insertions, 148 deletions

diff --git a/drivers/usb/host/xhci-dbg.c b/drivers/usb/host/xhci-dbg.c
index 56032f2..6d62e4a 100644
--- a/drivers/usb/host/xhci-dbg.c
+++ b/drivers/usb/host/xhci-dbg.c
@@ -173,6 +173,7 @@ void xhci_print_ir_set(struct xhci_hcd *xhci, struct xhci_intr_reg *ir_set, int
 {
 	void *addr;
 	u32 temp;
+	u64 temp_64;
 
 	addr = &ir_set->irq_pending;
 	temp = xhci_readl(xhci, addr);
@@ -200,25 +201,15 @@ void xhci_print_ir_set(struct xhci_hcd *xhci, struct xhci_intr_reg *ir_set, int
 		xhci_dbg(xhci, "  WARN: %p: ir_set.rsvd = 0x%x\n",
 				addr, (unsigned int)temp);
 
-	addr = &ir_set->erst_base[0];
-	temp = xhci_readl(xhci, addr);
-	xhci_dbg(xhci, "  %p: ir_set.erst_base[0] = 0x%x\n",
-			addr, (unsigned int) temp);
-
-	addr = &ir_set->erst_base[1];
-	temp = xhci_readl(xhci, addr);
-	xhci_dbg(xhci, "  %p: ir_set.erst_base[1] = 0x%x\n",
-			addr, (unsigned int) temp);
-
-	addr = &ir_set->erst_dequeue[0];
-	temp = xhci_readl(xhci, addr);
-	xhci_dbg(xhci, "  %p: ir_set.erst_dequeue[0] = 0x%x\n",
-			addr, (unsigned int) temp);
+	addr = &ir_set->erst_base;
+	temp_64 = xhci_read_64(xhci, addr);
+	xhci_dbg(xhci, "  %p: ir_set.erst_base = @%08llx\n",
+			addr, temp_64);
 
-	addr = &ir_set->erst_dequeue[1];
-	temp = xhci_readl(xhci, addr);
-	xhci_dbg(xhci, "  %p: ir_set.erst_dequeue[1] = 0x%x\n",
-			addr, (unsigned int) temp);
+	addr = &ir_set->erst_dequeue;
+	temp_64 = xhci_read_64(xhci, addr);
+	xhci_dbg(xhci, "  %p: ir_set.erst_dequeue = @%08llx\n",
+			addr, temp_64);
 }
 
 void xhci_print_run_regs(struct xhci_hcd *xhci)
@@ -268,8 +259,7 @@ void xhci_debug_trb(struct xhci_hcd *xhci, union xhci_trb *trb)
 		xhci_dbg(xhci, "Link TRB:\n");
 		xhci_print_trb_offsets(xhci, trb);
 
-		address = trb->link.segment_ptr[0] +
-			(((u64) trb->link.segment_ptr[1]) << 32);
+		address = trb->link.segment_ptr;
 		xhci_dbg(xhci, "Next ring segment DMA address = 0x%llx\n", address);
 
 		xhci_dbg(xhci, "Interrupter target = 0x%x\n",
@@ -282,8 +272,7 @@ void xhci_debug_trb(struct xhci_hcd *xhci, union xhci_trb *trb)
 				(unsigned int) (trb->link.control & TRB_NO_SNOOP));
 		break;
 	case TRB_TYPE(TRB_TRANSFER):
-		address = trb->trans_event.buffer[0] +
-			(((u64) trb->trans_event.buffer[1]) << 32);
+		address = trb->trans_event.buffer;
 		/*
 		 * FIXME: look at flags to figure out if it's an address or if
 		 * the data is directly in the buffer field.
@@ -291,8 +280,7 @@ void xhci_debug_trb(struct xhci_hcd *xhci, union xhci_trb *trb)
 		xhci_dbg(xhci, "DMA address or buffer contents= %llu\n", address);
 		break;
 	case TRB_TYPE(TRB_COMPLETION):
-		address = trb->event_cmd.cmd_trb[0] +
-			(((u64) trb->event_cmd.cmd_trb[1]) << 32);
+		address = trb->event_cmd.cmd_trb;
 		xhci_dbg(xhci, "Command TRB pointer = %llu\n", address);
 		xhci_dbg(xhci, "Completion status = %u\n",
 				(unsigned int) GET_COMP_CODE(trb->event_cmd.status));
@@ -328,8 +316,8 @@ void xhci_debug_segment(struct xhci_hcd *xhci, struct xhci_segment *seg)
 	for (i = 0; i < TRBS_PER_SEGMENT; ++i) {
 		trb = &seg->trbs[i];
 		xhci_dbg(xhci, "@%08x %08x %08x %08x %08x\n", addr,
-				(unsigned int) trb->link.segment_ptr[0],
-				(unsigned int) trb->link.segment_ptr[1],
+				lower_32_bits(trb->link.segment_ptr),
+				upper_32_bits(trb->link.segment_ptr),
 				(unsigned int) trb->link.intr_target,
 				(unsigned int) trb->link.control);
 		addr += sizeof(*trb);
@@ -386,8 +374,8 @@ void xhci_dbg_erst(struct xhci_hcd *xhci, struct xhci_erst *erst)
 		entry = &erst->entries[i];
 		xhci_dbg(xhci, "@%08x %08x %08x %08x %08x\n",
 				(unsigned int) addr,
-				(unsigned int) entry->seg_addr[0],
-				(unsigned int) entry->seg_addr[1],
+				lower_32_bits(entry->seg_addr),
+				upper_32_bits(entry->seg_addr),
 				(unsigned int) entry->seg_size,
 				(unsigned int) entry->rsvd);
 		addr += sizeof(*entry);
@@ -396,12 +384,13 @@ void xhci_dbg_erst(struct xhci_hcd *xhci, struct xhci_erst *erst)
 
 void xhci_dbg_cmd_ptrs(struct xhci_hcd *xhci)
 {
-	u32 val;
+	u64 val;
 
-	val = xhci_readl(xhci, &xhci->op_regs->cmd_ring[0]);
-	xhci_dbg(xhci, "// xHC command ring deq ptr low bits + flags = 0x%x\n", val);
-	val = xhci_readl(xhci, &xhci->op_regs->cmd_ring[1]);
-	xhci_dbg(xhci, "// xHC command ring deq ptr high bits = 0x%x\n", val);
+	val = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
+	xhci_dbg(xhci, "// xHC command ring deq ptr low bits + flags = @%08x\n",
+			lower_32_bits(val));
+	xhci_dbg(xhci, "// xHC command ring deq ptr high bits = @%08x\n",
+			upper_32_bits(val));
 }
 
 void xhci_dbg_ctx(struct xhci_hcd *xhci, struct xhci_device_control *ctx, dma_addr_t dma, unsigned int last_ep)
@@ -462,14 +451,10 @@ void xhci_dbg_ctx(struct xhci_hcd *xhci, struct xhci_device_control *ctx, dma_ad
 				&ctx->ep[i].ep_info2,
 				(unsigned long long)dma, ctx->ep[i].ep_info2);
 		dma += field_size;
-		xhci_dbg(xhci, "@%p (virt) @%08llx (dma) %#08x - deq[0]\n",
-				&ctx->ep[i].deq[0],
-				(unsigned long long)dma, ctx->ep[i].deq[0]);
-		dma += field_size;
-		xhci_dbg(xhci, "@%p (virt) @%08llx (dma) %#08x - deq[1]\n",
-				&ctx->ep[i].deq[1],
-				(unsigned long long)dma, ctx->ep[i].deq[1]);
-		dma += field_size;
+		xhci_dbg(xhci, "@%p (virt) @%08llx (dma) %#08llx - deq\n",
+				&ctx->ep[i].deq,
+				(unsigned long long)dma, ctx->ep[i].deq);
+		dma += 2*field_size;
 		xhci_dbg(xhci, "@%p (virt) @%08llx (dma) %#08x - tx_info\n",
 				&ctx->ep[i].tx_info,
 				(unsigned long long)dma, ctx->ep[i].tx_info);
diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
index ff99365..e157735 100644
--- a/drivers/usb/host/xhci-hcd.c
+++ b/drivers/usb/host/xhci-hcd.c
@@ -226,6 +226,7 @@ int xhci_init(struct usb_hcd *hcd)
 static void xhci_work(struct xhci_hcd *xhci)
 {
 	u32 temp;
+	u64 temp_64;
 
 	/*
 	 * Clear the op reg interrupt status first,
@@ -249,8 +250,8 @@ static void xhci_work(struct xhci_hcd *xhci)
 	xhci_handle_event(xhci);
 
 	/* Clear the event handler busy flag; the event ring should be empty. */
-	temp = xhci_readl(xhci, &xhci->ir_set->erst_dequeue[0]);
-	xhci_writel(xhci, temp & ~ERST_EHB, &xhci->ir_set->erst_dequeue[0]);
+	temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
+	xhci_write_64(xhci, temp_64 & ~ERST_EHB, &xhci->ir_set->erst_dequeue);
 	/* Flush posted writes -- FIXME is this necessary? */
 	xhci_readl(xhci, &xhci->ir_set->irq_pending);
 }
@@ -295,6 +296,7 @@ void xhci_event_ring_work(unsigned long arg)
 {
 	unsigned long flags;
 	int temp;
+	u64 temp_64;
 	struct xhci_hcd *xhci = (struct xhci_hcd *) arg;
 	int i, j;
 
@@ -311,9 +313,9 @@ void xhci_event_ring_work(unsigned long arg)
 	xhci_dbg(xhci, "Event ring:\n");
 	xhci_debug_segment(xhci, xhci->event_ring->deq_seg);
 	xhci_dbg_ring_ptrs(xhci, xhci->event_ring);
-	temp = xhci_readl(xhci, &xhci->ir_set->erst_dequeue[0]);
-	temp &= ERST_PTR_MASK;
-	xhci_dbg(xhci, "ERST deq = 0x%x\n", temp);
+	temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
+	temp_64 &= ~ERST_PTR_MASK;
+	xhci_dbg(xhci, "ERST deq = 64'h%0lx\n", (long unsigned int) temp_64);
 	xhci_dbg(xhci, "Command ring:\n");
 	xhci_debug_segment(xhci, xhci->cmd_ring->deq_seg);
 	xhci_dbg_ring_ptrs(xhci, xhci->cmd_ring);
@@ -356,6 +358,7 @@ void xhci_event_ring_work(unsigned long arg)
 int xhci_run(struct usb_hcd *hcd)
 {
 	u32 temp;
+	u64 temp_64;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 	void (*doorbell)(struct xhci_hcd *) = NULL;
 
@@ -416,11 +419,9 @@ int xhci_run(struct usb_hcd *hcd)
 	xhci_dbg(xhci, "Event ring:\n");
 	xhci_debug_ring(xhci, xhci->event_ring);
 	xhci_dbg_ring_ptrs(xhci, xhci->event_ring);
-	temp = xhci_readl(xhci, &xhci->ir_set->erst_dequeue[0]);
-	temp &= ERST_PTR_MASK;
-	xhci_dbg(xhci, "ERST deq = 0x%x\n", temp);
-	temp = xhci_readl(xhci, &xhci->ir_set->erst_dequeue[1]);
-	xhci_dbg(xhci, "ERST deq upper = 0x%x\n", temp);
+	temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
+	temp_64 &= ~ERST_PTR_MASK;
+	xhci_dbg(xhci, "ERST deq = 64'h%0lx\n", (long unsigned int) temp_64);
 
 	temp = xhci_readl(xhci, &xhci->op_regs->command);
 	temp |= (CMD_RUN);
@@ -888,8 +889,7 @@ static void xhci_zero_in_ctx(struct xhci_virt_device *virt_dev)
 		ep_ctx = &virt_dev->in_ctx->ep[i];
 		ep_ctx->ep_info = 0;
 		ep_ctx->ep_info2 = 0;
-		ep_ctx->deq[0] = 0;
-		ep_ctx->deq[1] = 0;
+		ep_ctx->deq = 0;
 		ep_ctx->tx_info = 0;
 	}
 }
@@ -1165,7 +1165,7 @@ int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev)
 	struct xhci_virt_device *virt_dev;
 	int ret = 0;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-	u32 temp;
+	u64 temp_64;
 
 	if (!udev->slot_id) {
 		xhci_dbg(xhci, "Bad Slot ID %d\n", udev->slot_id);
@@ -1227,18 +1227,13 @@ int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev)
 	if (ret) {
 		return ret;
 	}
-	temp = xhci_readl(xhci, &xhci->op_regs->dcbaa_ptr[0]);
-	xhci_dbg(xhci, "Op regs DCBAA ptr[0] = %#08x\n", temp);
-	temp = xhci_readl(xhci, &xhci->op_regs->dcbaa_ptr[1]);
-	xhci_dbg(xhci, "Op regs DCBAA ptr[1] = %#08x\n", temp);
-	xhci_dbg(xhci, "Slot ID %d dcbaa entry[0] @%p = %#08x\n",
-			udev->slot_id,
-			&xhci->dcbaa->dev_context_ptrs[2*udev->slot_id],
-			xhci->dcbaa->dev_context_ptrs[2*udev->slot_id]);
-	xhci_dbg(xhci, "Slot ID %d dcbaa entry[1] @%p = %#08x\n",
+	temp_64 = xhci_read_64(xhci, &xhci->op_regs->dcbaa_ptr);
+	xhci_dbg(xhci, "Op regs DCBAA ptr = %#016llx\n", temp_64);
+	xhci_dbg(xhci, "Slot ID %d dcbaa entry @%p = %#016llx\n",
 			udev->slot_id,
-			&xhci->dcbaa->dev_context_ptrs[2*udev->slot_id+1],
-			xhci->dcbaa->dev_context_ptrs[2*udev->slot_id+1]);
+			&xhci->dcbaa->dev_context_ptrs[udev->slot_id],
+			(unsigned long long)
+				xhci->dcbaa->dev_context_ptrs[udev->slot_id]);
 	xhci_dbg(xhci, "Output Context DMA address = %#08llx\n",
 			(unsigned long long)virt_dev->out_ctx_dma);
 	xhci_dbg(xhci, "Slot ID %d Input Context:\n", udev->slot_id);
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index c8a72de..ec825f1 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -88,7 +88,7 @@ static void xhci_link_segments(struct xhci_hcd *xhci, struct xhci_segment *prev,
 		return;
 	prev->next = next;
 	if (link_trbs) {
-		prev->trbs[TRBS_PER_SEGMENT-1].link.segment_ptr[0] = next->dma;
+		prev->trbs[TRBS_PER_SEGMENT-1].link.segment_ptr = next->dma;
 
 		/* Set the last TRB in the segment to have a TRB type ID of Link TRB */
 		val = prev->trbs[TRBS_PER_SEGMENT-1].link.control;
@@ -200,8 +200,7 @@ void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id)
 		return;
 
 	dev = xhci->devs[slot_id];
-	xhci->dcbaa->dev_context_ptrs[2*slot_id] = 0;
-	xhci->dcbaa->dev_context_ptrs[2*slot_id + 1] = 0;
+	xhci->dcbaa->dev_context_ptrs[slot_id] = 0;
 	if (!dev)
 		return;
 
@@ -265,13 +264,12 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
 	 * Point to output device context in dcbaa; skip the output control
 	 * context, which is eight 32 bit fields (or 32 bytes long)
 	 */
-	xhci->dcbaa->dev_context_ptrs[2*slot_id] =
+	xhci->dcbaa->dev_context_ptrs[slot_id] =
 		(u32) dev->out_ctx_dma + (32);
 	xhci_dbg(xhci, "Set slot id %d dcbaa entry %p to 0x%llx\n",
 			slot_id,
-			&xhci->dcbaa->dev_context_ptrs[2*slot_id],
+			&xhci->dcbaa->dev_context_ptrs[slot_id],
 			(unsigned long long)dev->out_ctx_dma);
-	xhci->dcbaa->dev_context_ptrs[2*slot_id + 1] = 0;
 
 	return 1;
 fail:
@@ -360,10 +358,9 @@ int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *ud
 	ep0_ctx->ep_info2 |= MAX_BURST(0);
 	ep0_ctx->ep_info2 |= ERROR_COUNT(3);
 
-	ep0_ctx->deq[0] =
+	ep0_ctx->deq =
 		dev->ep_rings[0]->first_seg->dma;
-	ep0_ctx->deq[0] |= dev->ep_rings[0]->cycle_state;
-	ep0_ctx->deq[1] = 0;
+	ep0_ctx->deq |= dev->ep_rings[0]->cycle_state;
 
 	/* Steps 7 and 8 were done in xhci_alloc_virt_device() */
 
@@ -477,8 +474,7 @@ int xhci_endpoint_init(struct xhci_hcd *xhci,
 	if (!virt_dev->new_ep_rings[ep_index])
 		return -ENOMEM;
 	ep_ring = virt_dev->new_ep_rings[ep_index];
-	ep_ctx->deq[0] = ep_ring->first_seg->dma | ep_ring->cycle_state;
-	ep_ctx->deq[1] = 0;
+	ep_ctx->deq = ep_ring->first_seg->dma | ep_ring->cycle_state;
 
 	ep_ctx->ep_info = xhci_get_endpoint_interval(udev, ep);
 
@@ -535,8 +531,7 @@ void xhci_endpoint_zero(struct xhci_hcd *xhci,
 
 	ep_ctx->ep_info = 0;
 	ep_ctx->ep_info2 = 0;
-	ep_ctx->deq[0] = 0;
-	ep_ctx->deq[1] = 0;
+	ep_ctx->deq = 0;
 	ep_ctx->tx_info = 0;
 	/* Don't free the endpoint ring until the set interface or configuration
 	 * request succeeds.
@@ -551,10 +546,8 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
 
 	/* Free the Event Ring Segment Table and the actual Event Ring */
 	xhci_writel(xhci, 0, &xhci->ir_set->erst_size);
-	xhci_writel(xhci, 0, &xhci->ir_set->erst_base[0]);
-	xhci_writel(xhci, 0, &xhci->ir_set->erst_base[1]);
-	xhci_writel(xhci, 0, &xhci->ir_set->erst_dequeue[0]);
-	xhci_writel(xhci, 0, &xhci->ir_set->erst_dequeue[1]);
+	xhci_write_64(xhci, 0, &xhci->ir_set->erst_base);
+	xhci_write_64(xhci, 0, &xhci->ir_set->erst_dequeue);
 	size = sizeof(struct xhci_erst_entry)*(xhci->erst.num_entries);
 	if (xhci->erst.entries)
 		pci_free_consistent(pdev, size,
@@ -566,8 +559,7 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
 	xhci->event_ring = NULL;
 	xhci_dbg(xhci, "Freed event ring\n");
 
-	xhci_writel(xhci, 0, &xhci->op_regs->cmd_ring[0]);
-	xhci_writel(xhci, 0, &xhci->op_regs->cmd_ring[1]);
+	xhci_write_64(xhci, 0, &xhci->op_regs->cmd_ring);
 	if (xhci->cmd_ring)
 		xhci_ring_free(xhci, xhci->cmd_ring);
 	xhci->cmd_ring = NULL;
@@ -586,8 +578,7 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
 	xhci->device_pool = NULL;
 	xhci_dbg(xhci, "Freed device context pool\n");
 
-	xhci_writel(xhci, 0, &xhci->op_regs->dcbaa_ptr[0]);
-	xhci_writel(xhci, 0, &xhci->op_regs->dcbaa_ptr[1]);
+	xhci_write_64(xhci, 0, &xhci->op_regs->dcbaa_ptr);
 	if (xhci->dcbaa)
 		pci_free_consistent(pdev, sizeof(*xhci->dcbaa),
 				xhci->dcbaa, xhci->dcbaa->dma);
@@ -602,6 +593,7 @@ 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;
 	int i;
@@ -647,8 +639,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	xhci->dcbaa->dma = dma;
 	xhci_dbg(xhci, "// Device context base array address = 0x%llx (DMA), %p (virt)\n",
 			(unsigned long long)xhci->dcbaa->dma, xhci->dcbaa);
-	xhci_writel(xhci, dma, &xhci->op_regs->dcbaa_ptr[0]);
-	xhci_writel(xhci, (u32) 0, &xhci->op_regs->dcbaa_ptr[1]);
+	xhci_write_64(xhci, dma, &xhci->op_regs->dcbaa_ptr);
 
 	/*
 	 * Initialize the ring segment pool.  The ring must be a contiguous
@@ -675,14 +666,12 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 			(unsigned long long)xhci->cmd_ring->first_seg->dma);
 
 	/* Set the address in the Command Ring Control register */
-	val = xhci_readl(xhci, &xhci->op_regs->cmd_ring[0]);
-	val = (val & ~CMD_RING_ADDR_MASK) |
-		(xhci->cmd_ring->first_seg->dma & CMD_RING_ADDR_MASK) |
+	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(xhci, "// Setting command ring address low bits to 0x%x\n", val);
-	xhci_writel(xhci, val, &xhci->op_regs->cmd_ring[0]);
-	xhci_dbg(xhci, "// Setting command ring address high bits to 0x0\n");
-	xhci_writel(xhci, (u32) 0, &xhci->op_regs->cmd_ring[1]);
+	xhci_dbg(xhci, "// Setting command ring address to 0x%x\n", val);
+	xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
 	xhci_dbg_cmd_ptrs(xhci);
 
 	val = xhci_readl(xhci, &xhci->cap_regs->db_off);
@@ -722,8 +711,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	/* 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[0] = seg->dma;
-		entry->seg_addr[1] = 0;
+		entry->seg_addr = seg->dma;
 		entry->seg_size = TRBS_PER_SEGMENT;
 		entry->rsvd = 0;
 		seg = seg->next;
@@ -741,11 +729,10 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	/* set the segment table base address */
 	xhci_dbg(xhci, "// Set ERST base address for ir_set 0 = 0x%llx\n",
 			(unsigned long long)xhci->erst.erst_dma_addr);
-	val = xhci_readl(xhci, &xhci->ir_set->erst_base[0]);
-	val &= ERST_PTR_MASK;
-	val |= (xhci->erst.erst_dma_addr & ~ERST_PTR_MASK);
-	xhci_writel(xhci, val, &xhci->ir_set->erst_base[0]);
-	xhci_writel(xhci, 0, &xhci->ir_set->erst_base[1]);
+	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);
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index d672ba1..588686f 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -237,7 +237,7 @@ static int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring,
 
 void xhci_set_hc_event_deq(struct xhci_hcd *xhci)
 {
-	u32 temp;
+	u64 temp;
 	dma_addr_t deq;
 
 	deq = xhci_trb_virt_to_dma(xhci->event_ring->deq_seg,
@@ -246,13 +246,12 @@ void xhci_set_hc_event_deq(struct xhci_hcd *xhci)
 		xhci_warn(xhci, "WARN something wrong with SW event ring "
 				"dequeue ptr.\n");
 	/* Update HC event ring dequeue pointer */
-	temp = xhci_readl(xhci, &xhci->ir_set->erst_dequeue[0]);
+	temp = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
 	temp &= ERST_PTR_MASK;
 	if (!in_interrupt())
 		xhci_dbg(xhci, "// Write event ring dequeue pointer\n");
-	xhci_writel(xhci, 0, &xhci->ir_set->erst_dequeue[1]);
-	xhci_writel(xhci, (deq & ~ERST_PTR_MASK) | temp,
-			&xhci->ir_set->erst_dequeue[0]);
+	xhci_write_64(xhci, ((u64) deq & (u64) ~ERST_PTR_MASK) | temp,
+			&xhci->ir_set->erst_dequeue);
 }
 
 /* Ring the host controller doorbell after placing a command on the ring */
@@ -352,7 +351,7 @@ static void find_new_dequeue_state(struct xhci_hcd *xhci,
 	if (!state->new_deq_seg)
 		BUG();
 	/* Dig out the cycle state saved by the xHC during the stop ep cmd */
-	state->new_cycle_state = 0x1 & dev->out_ctx->ep[ep_index].deq[0];
+	state->new_cycle_state = 0x1 & dev->out_ctx->ep[ep_index].deq;
 
 	state->new_deq_ptr = cur_td->last_trb;
 	state->new_deq_seg = find_trb_seg(state->new_deq_seg,
@@ -594,10 +593,8 @@ static void handle_set_deq_completion(struct xhci_hcd *xhci,
 		 * cancelling URBs, which might not be an error...
 		 */
 	} else {
-		xhci_dbg(xhci, "Successful Set TR Deq Ptr cmd, deq[0] = 0x%x, "
-				"deq[1] = 0x%x.\n",
-				dev->out_ctx->ep[ep_index].deq[0],
-				dev->out_ctx->ep[ep_index].deq[1]);
+		xhci_dbg(xhci, "Successful Set TR Deq Ptr cmd, deq = @%08llx\n",
+				dev->out_ctx->ep[ep_index].deq);
 	}
 
 	ep_ring->state &= ~SET_DEQ_PENDING;
@@ -631,7 +628,7 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
 	u64 cmd_dma;
 	dma_addr_t cmd_dequeue_dma;
 
-	cmd_dma = (((u64) event->cmd_trb[1]) << 32) + event->cmd_trb[0];
+	cmd_dma = event->cmd_trb;
 	cmd_dequeue_dma = xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
 			xhci->cmd_ring->dequeue);
 	/* Is the command ring deq ptr out of sync with the deq seg ptr? */
@@ -794,10 +791,7 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 		return -ENODEV;
 	}
 
-	event_dma = event->buffer[0];
-	if (event->buffer[1] != 0)
-		xhci_warn(xhci, "WARN ignoring upper 32-bits of 64-bit TRB dma address\n");
-
+	event_dma = event->buffer;
 	/* This TRB should be in the TD at the head of this ring's TD list */
 	if (list_empty(&ep_ring->td_list)) {
 		xhci_warn(xhci, "WARN Event TRB for slot %d ep %d with no TDs queued?\n",
@@ -821,10 +815,10 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 	event_trb = &event_seg->trbs[(event_dma - event_seg->dma) / sizeof(*event_trb)];
 	xhci_dbg(xhci, "Event TRB with TRB type ID %u\n",
 			(unsigned int) (event->flags & TRB_TYPE_BITMASK)>>10);
-	xhci_dbg(xhci, "Offset 0x00 (buffer[0]) = 0x%x\n",
-			(unsigned int) event->buffer[0]);
-	xhci_dbg(xhci, "Offset 0x04 (buffer[0]) = 0x%x\n",
-			(unsigned int) event->buffer[1]);
+	xhci_dbg(xhci, "Offset 0x00 (buffer lo) = 0x%x\n",
+			lower_32_bits(event->buffer));
+	xhci_dbg(xhci, "Offset 0x04 (buffer hi) = 0x%x\n",
+			upper_32_bits(event->buffer));
 	xhci_dbg(xhci, "Offset 0x08 (transfer length) = 0x%x\n",
 			(unsigned int) event->transfer_len);
 	xhci_dbg(xhci, "Offset 0x0C (flags) = 0x%x\n",
@@ -1343,8 +1337,8 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 			TD_REMAINDER(urb->transfer_buffer_length - running_total) |
 			TRB_INTR_TARGET(0);
 		queue_trb(xhci, ep_ring, false,
-				(u32) addr,
-				(u32) ((u64) addr >> 32),
+				lower_32_bits(addr),
+				upper_32_bits(addr),
 				length_field,
 				/* We always want to know if the TRB was short,
 				 * or we won't get an event when it completes.
@@ -1475,8 +1469,8 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 			TD_REMAINDER(urb->transfer_buffer_length - running_total) |
 			TRB_INTR_TARGET(0);
 		queue_trb(xhci, ep_ring, false,
-				(u32) addr,
-				(u32) ((u64) addr >> 32),
+				lower_32_bits(addr),
+				upper_32_bits(addr),
 				length_field,
 				/* We always want to know if the TRB was short,
 				 * or we won't get an event when it completes.
@@ -1637,7 +1631,8 @@ int xhci_queue_slot_control(struct xhci_hcd *xhci, u32 trb_type, u32 slot_id)
 int xhci_queue_address_device(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
 		u32 slot_id)
 {
-	return queue_command(xhci, in_ctx_ptr, 0, 0,
+	return queue_command(xhci, lower_32_bits(in_ctx_ptr),
+			upper_32_bits(in_ctx_ptr), 0,
 			TRB_TYPE(TRB_ADDR_DEV) | SLOT_ID_FOR_TRB(slot_id));
 }
 
@@ -1645,7 +1640,8 @@ int xhci_queue_address_device(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
 int xhci_queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
 		u32 slot_id)
 {
-	return queue_command(xhci, in_ctx_ptr, 0, 0,
+	return queue_command(xhci, lower_32_bits(in_ctx_ptr),
+			upper_32_bits(in_ctx_ptr), 0,
 			TRB_TYPE(TRB_CONFIG_EP) | SLOT_ID_FOR_TRB(slot_id));
 }
 
@@ -1677,7 +1673,8 @@ static int queue_set_tr_deq(struct xhci_hcd *xhci, int slot_id,
 		xhci_warn(xhci, "WARN Cannot submit Set TR Deq Ptr\n");
 		xhci_warn(xhci, "WARN deq seg = %p, deq pt = %p\n",
 				deq_seg, deq_ptr);
-	return queue_command(xhci, (u32) addr | cycle_state, 0, 0,
+	return queue_command(xhci, lower_32_bits(addr) | cycle_state,
+			upper_32_bits(addr), 0,
 			trb_slot_id | trb_ep_index | type);
 }
 
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index cde648a..60770c8 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -25,6 +25,7 @@
 
 #include <linux/usb.h>
 #include <linux/timer.h>
+#include <linux/kernel.h>
 
 #include "../core/hcd.h"
 /* Code sharing between pci-quirks and xhci hcd */
@@ -42,14 +43,6 @@
  * xHCI register interface.
  * This corresponds to the eXtensible Host Controller Interface (xHCI)
  * Revision 0.95 specification
- *
- * Registers should always be accessed with double word or quad word accesses.
- *
- * Some xHCI implementations may support 64-bit address pointers.  Registers
- * with 64-bit address pointers should be written to with dword accesses by
- * writing the low dword first (ptr[0]), then the high dword (ptr[1]) second.
- * xHCI implementations that do not support 64-bit address pointers will ignore
- * the high dword, and write order is irrelevant.
  */
 
 /**
@@ -166,10 +159,10 @@ struct xhci_op_regs {
 	u32	reserved1;
 	u32	reserved2;
 	u32	dev_notification;
-	u32	cmd_ring[2];
+	u64	cmd_ring;
 	/* rsvd: offset 0x20-2F */
 	u32	reserved3[4];
-	u32	dcbaa_ptr[2];
+	u64	dcbaa_ptr;
 	u32	config_reg;
 	/* rsvd: offset 0x3C-3FF */
 	u32	reserved4[241];
@@ -254,7 +247,7 @@ struct xhci_op_regs {
 #define CMD_RING_RUNNING	(1 << 3)
 /* bits 4:5 reserved and should be preserved */
 /* Command Ring pointer - bit mask for the lower 32 bits. */
-#define CMD_RING_ADDR_MASK	(0xffffffc0)
+#define CMD_RING_RSVD_BITS	(0x3f)
 
 /* CONFIG - Configure Register - config_reg bitmasks */
 /* bits 0:7 - maximum number of device slots enabled (NumSlotsEn) */
@@ -382,8 +375,8 @@ struct xhci_intr_reg {
 	u32	irq_control;
 	u32	erst_size;
 	u32	rsvd;
-	u32	erst_base[2];
-	u32	erst_dequeue[2];
+	u64	erst_base;
+	u64	erst_dequeue;
 };
 
 /* irq_pending bitmasks */
@@ -538,7 +531,7 @@ struct xhci_slot_ctx {
 struct xhci_ep_ctx {
 	u32	ep_info;
 	u32	ep_info2;
-	u32	deq[2];
+	u64	deq;
 	u32	tx_info;
 	/* offset 0x14 - 0x1f reserved for HC internal use */
 	u32	reserved[3];
@@ -641,7 +634,7 @@ struct xhci_virt_device {
  */
 struct xhci_device_context_array {
 	/* 64-bit device addresses; we only write 32-bit addresses */
-	u32			dev_context_ptrs[2*MAX_HC_SLOTS];
+	u64			dev_context_ptrs[MAX_HC_SLOTS];
 	/* private xHCD pointers */
 	dma_addr_t	dma;
 };
@@ -654,7 +647,7 @@ struct xhci_device_context_array {
 
 struct xhci_stream_ctx {
 	/* 64-bit stream ring address, cycle state, and stream type */
-	u32	stream_ring[2];
+	u64	stream_ring;
 	/* offset 0x14 - 0x1f reserved for HC internal use */
 	u32	reserved[2];
 };
@@ -662,7 +655,7 @@ struct xhci_stream_ctx {
 
 struct xhci_transfer_event {
 	/* 64-bit buffer address, or immediate data */
-	u32	buffer[2];
+	u64	buffer;
 	u32	transfer_len;
 	/* This field is interpreted differently based on the type of TRB */
 	u32	flags;
@@ -744,7 +737,7 @@ struct xhci_transfer_event {
 
 struct xhci_link_trb {
 	/* 64-bit segment pointer*/
-	u32 segment_ptr[2];
+	u64 segment_ptr;
 	u32 intr_target;
 	u32 control;
 };
@@ -755,7 +748,7 @@ struct xhci_link_trb {
 /* Command completion event TRB */
 struct xhci_event_cmd {
 	/* Pointer to command TRB, or the value passed by the event data trb */
-	u32 cmd_trb[2];
+	u64 cmd_trb;
 	u32 status;
 	u32 flags;
 };
@@ -943,7 +936,7 @@ struct xhci_ring {
 
 struct xhci_erst_entry {
 	/* 64-bit event ring segment address */
-	u32	seg_addr[2];
+	u64	seg_addr;
 	u32	seg_size;
 	/* Set to zero */
 	u32	rsvd;
@@ -1079,6 +1072,38 @@ static inline void xhci_writel(struct xhci_hcd *xhci,
 	writel(val, regs);
 }
 
+/*
+ * Registers should always be accessed with double word or quad word accesses.
+ *
+ * Some xHCI implementations may support 64-bit address pointers.  Registers
+ * with 64-bit address pointers should be written to with dword accesses by
+ * writing the low dword first (ptr[0]), then the high dword (ptr[1]) second.
+ * xHCI implementations that do not support 64-bit address pointers will ignore
+ * the high dword, and write order is irrelevant.
+ */
+static inline u64 xhci_read_64(const struct xhci_hcd *xhci,
+		__u64 __iomem *regs)
+{
+	__u32 __iomem *ptr = (__u32 __iomem *) regs;
+	u64 val_lo = readl(ptr);
+	u64 val_hi = readl(ptr + 1);
+	return val_lo + (val_hi << 32);
+}
+static inline void xhci_write_64(struct xhci_hcd *xhci,
+		const u64 val, __u64 __iomem *regs)
+{
+	__u32 __iomem *ptr = (__u32 __iomem *) regs;
+	u32 val_lo = lower_32_bits(val);
+	u32 val_hi = upper_32_bits(val);
+
+	if (!in_interrupt())
+		xhci_dbg(xhci,
+			 "`MEM_WRITE_DWORD(3'b000, 64'h%p, 64'h%0lx, 4'hf);\n",
+			 regs, (long unsigned int) val);
+	writel(val_lo, ptr);
+	writel(val_hi, ptr + 1);
+}
+
 /* xHCI debugging */
 void xhci_print_ir_set(struct xhci_hcd *xhci, struct xhci_intr_reg *ir_set, int set_num);
 void xhci_print_registers(struct xhci_hcd *xhci);