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Commit a2490187 authored by Paul Zimmerman's avatar Paul Zimmerman Committed by Sarah Sharp
Browse files

xhci: Clarify some expressions in the TRB math 



This makes it easier to spot some problems, which will be fixed by the
next patch in the series. Also change dev_dbg to dev_err in
check_trb_math(), so any math errors will be visible even when running
with debug disabled.

Note: This patch changes the expressions containing
"((1 << TRB_MAX_BUFF_SHIFT) - 1)" to use the equivalent
"(TRB_MAX_BUFF_SIZE - 1)". No change in behavior is intended for
those expressions.

This patch should be queued for stable kernels back to 2.6.31.

Signed-off-by: default avatarPaul Zimmerman <paulz@synopsys.com>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@kernel.org
parent 68e41c5d

drivers/usb/host/xhci-ring.c

+10 −12
Original line number Diff line number Diff line
@@ -2368,7 +2368,7 @@ static unsigned int count_sg_trbs_needed(struct xhci_hcd *xhci, struct urb *urb) 


		/* Scatter gather list entries may cross 64KB boundaries */

		running_total = TRB_MAX_BUFF_SIZE -

			(sg_dma_address(sg) & ((1 << TRB_MAX_BUFF_SHIFT) - 1));

			(sg_dma_address(sg) & (TRB_MAX_BUFF_SIZE - 1));

		if (running_total != 0)

			num_trbs++;
@@ -2399,11 +2399,11 @@ static unsigned int count_sg_trbs_needed(struct xhci_hcd *xhci, struct urb *urb) 
static void check_trb_math(struct urb *urb, int num_trbs, int running_total)

{

	if (num_trbs != 0)

		dev_dbg(&urb->dev->dev, "%s - ep %#x - Miscalculated number of "

		dev_err(&urb->dev->dev, "%s - ep %#x - Miscalculated number of "

				"TRBs, %d left\n", __func__,

				urb->ep->desc.bEndpointAddress, num_trbs);

	if (running_total != urb->transfer_buffer_length)

		dev_dbg(&urb->dev->dev, "%s - ep %#x - Miscalculated tx length, "

		dev_err(&urb->dev->dev, "%s - ep %#x - Miscalculated tx length, "

				"queued %#x (%d), asked for %#x (%d)\n",

				__func__,

				urb->ep->desc.bEndpointAddress,
@@ -2538,8 +2538,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags, 
	sg = urb->sg;

	addr = (u64) sg_dma_address(sg);

	this_sg_len = sg_dma_len(sg);

	trb_buff_len = TRB_MAX_BUFF_SIZE -

		(addr & ((1 << TRB_MAX_BUFF_SHIFT) - 1));

	trb_buff_len = TRB_MAX_BUFF_SIZE - (addr & (TRB_MAX_BUFF_SIZE - 1));

	trb_buff_len = min_t(int, trb_buff_len, this_sg_len);

	if (trb_buff_len > urb->transfer_buffer_length)

		trb_buff_len = urb->transfer_buffer_length;
@@ -2577,7 +2576,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags, 
				(unsigned int) (addr + TRB_MAX_BUFF_SIZE) & ~(TRB_MAX_BUFF_SIZE - 1),

				(unsigned int) addr + trb_buff_len);

		if (TRB_MAX_BUFF_SIZE -

				(addr & ((1 << TRB_MAX_BUFF_SHIFT) - 1)) < trb_buff_len) {

				(addr & (TRB_MAX_BUFF_SIZE - 1)) < trb_buff_len) {

			xhci_warn(xhci, "WARN: sg dma xfer crosses 64KB boundaries!\n");

			xhci_dbg(xhci, "Next boundary at %#x, end dma = %#x\n",

					(unsigned int) (addr + TRB_MAX_BUFF_SIZE) & ~(TRB_MAX_BUFF_SIZE - 1),
@@ -2621,7 +2620,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags, 
		}



		trb_buff_len = TRB_MAX_BUFF_SIZE -

			(addr & ((1 << TRB_MAX_BUFF_SHIFT) - 1));

			(addr & (TRB_MAX_BUFF_SIZE - 1));

		trb_buff_len = min_t(int, trb_buff_len, this_sg_len);

		if (running_total + trb_buff_len > urb->transfer_buffer_length)

			trb_buff_len =
@@ -2661,7 +2660,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags, 
	num_trbs = 0;

	/* How much data is (potentially) left before the 64KB boundary? */

	running_total = TRB_MAX_BUFF_SIZE -

		(urb->transfer_dma & ((1 << TRB_MAX_BUFF_SHIFT) - 1));

		(urb->transfer_dma & (TRB_MAX_BUFF_SIZE - 1));



	/* If there's some data on this 64KB chunk, or we have to send a

	 * zero-length transfer, we need at least one TRB
@@ -2705,8 +2704,8 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags, 
	/* How much data is in the first TRB? */

	addr = (u64) urb->transfer_dma;

	trb_buff_len = TRB_MAX_BUFF_SIZE -

		(urb->transfer_dma & ((1 << TRB_MAX_BUFF_SHIFT) - 1));

	if (urb->transfer_buffer_length < trb_buff_len)

		(urb->transfer_dma & (TRB_MAX_BUFF_SIZE - 1));

	if (trb_buff_len > urb->transfer_buffer_length)

		trb_buff_len = urb->transfer_buffer_length;



	first_trb = true;
@@ -2884,8 +2883,7 @@ static int count_isoc_trbs_needed(struct xhci_hcd *xhci, 
	addr = (u64) (urb->transfer_dma + urb->iso_frame_desc[i].offset);

	td_len = urb->iso_frame_desc[i].length;



	running_total = TRB_MAX_BUFF_SIZE -

			(addr & ((1 << TRB_MAX_BUFF_SHIFT) - 1));

	running_total = TRB_MAX_BUFF_SIZE - (addr & (TRB_MAX_BUFF_SIZE - 1));

	if (running_total != 0)

		num_trbs++;