Commit 40c30410 authored by Frank Li's avatar Frank Li Committed by Greg Kroah-Hartman
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usb: cdns3: Fix uvc fail when DMA cross 4k boundery since sg enabled 



Supposed DMA cross 4k bounder problem should be fixed at DEV_VER_V2, but
still met problem when do ISO transfer if sg enabled.

Data pattern likes below when sg enabled, package size is 1k and mult is 2
	[UVC Header(8B) ] [data(3k - 8)] ...

The received data at offset 0xd000 will get 0xc000 data, len 0x70. Error
happen position as below pattern:
	0xd000: wrong
	0xe000: wrong
	0xf000: correct
	0x10000: wrong
	0x11000: wrong
	0x12000: correct
	...

To avoid DMA cross 4k bounder at ISO transfer, reduce burst len according
to start DMA address's alignment.

Cc:  <stable@vger.kernel.org>
Fixes: 7733f6c3 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Signed-off-by: default avatarFrank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20231224153816.1664687-4-Frank.Li@nxp.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 92f02efa

drivers/usb/cdns3/cdns3-gadget.c

+31 −1
Original line number Diff line number Diff line
@@ -1120,6 +1120,7 @@ static int cdns3_ep_run_transfer(struct cdns3_endpoint *priv_ep, 
	u32 togle_pcs = 1;

	int sg_iter = 0;

	int num_trb_req;

	int trb_burst;

	int num_trb;

	int address;

	u32 control;
@@ -1243,7 +1244,36 @@ static int cdns3_ep_run_transfer(struct cdns3_endpoint *priv_ep, 
			total_tdl += DIV_ROUND_UP(length,

					       priv_ep->endpoint.maxpacket);



		trb->length |= cpu_to_le32(TRB_BURST_LEN(priv_ep->trb_burst_size) |

		trb_burst = priv_ep->trb_burst_size;



		/*

		 * Supposed DMA cross 4k bounder problem should be fixed at DEV_VER_V2, but still

		 * met problem when do ISO transfer if sg enabled.

		 *

		 * Data pattern likes below when sg enabled, package size is 1k and mult is 2

		 *       [UVC Header(8B) ] [data(3k - 8)] ...

		 *

		 * The received data at offset 0xd000 will get 0xc000 data, len 0x70. Error happen

		 * as below pattern:

		 *	0xd000: wrong

		 *	0xe000: wrong

		 *	0xf000: correct

		 *	0x10000: wrong

		 *	0x11000: wrong

		 *	0x12000: correct

		 *	...

		 *

		 * But it is still unclear about why error have not happen below 0xd000, it should

		 * cross 4k bounder. But anyway, the below code can fix this problem.

		 *

		 * To avoid DMA cross 4k bounder at ISO transfer, reduce burst len according to 16.

		 */

		if (priv_ep->type == USB_ENDPOINT_XFER_ISOC && priv_dev->dev_ver <= DEV_VER_V2)

			if (ALIGN_DOWN(trb->buffer, SZ_4K) !=

			    ALIGN_DOWN(trb->buffer + length, SZ_4K))

				trb_burst = 16;



		trb->length |= cpu_to_le32(TRB_BURST_LEN(trb_burst) |

					TRB_LEN(length));

		pcs = priv_ep->pcs ? TRB_CYCLE : 0;