FAILED: patch "[PATCH] usb: cdns3: Fix uvc fail when DMA cross 4k boundery since sg" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 40c304109e866a7dc123661a5c8ca72f6b5e14e0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024012238-borough-parameter-5f3f@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

40c304109e86 ("usb: cdns3: Fix uvc fail when DMA cross 4k boundery since sg enabled") 1b8be5ecff26 ("usb: cdns3: fix uvc failure work since sg support enabled") 387c2b6ba197 ("usb: cdns3: gadget: fix new urb never complete if ep cancel previous requests") fba8701baed7 ("usb: cdns3: Fixes for sparse warnings")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 40c304109e866a7dc123661a5c8ca72f6b5e14e0 Mon Sep 17 00:00:00 2001
From: Frank Li <[email protected]>
Date: Sun, 24 Dec 2023 10:38:15 -0500
Subject: [PATCH] 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.

index 4c6893af22dd..aeca902ab6cc 100644
@@ -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;