This is a note to let you know that I've just added the patch titled
usb: cdns3: Fix uvc fail when DMA cross 4k boundery since sg enabled
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-cdns3-fix-uvc-fail-when-dma-cross-4k-boundery-si.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 05aad0082bf48fcac8be321c53eb97c3815ad73b
Author: Frank Li <Frank.Li@xxxxxxx>
Date: Sun Dec 24 10:38:15 2023 -0500
usb: cdns3: Fix uvc fail when DMA cross 4k boundery since sg enabled
[ Upstream commit 40c304109e866a7dc123661a5c8ca72f6b5e14e0 ]
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@xxxxxxxxxxxxxxx>
Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
Link: https://lore.kernel.org/r/20231224153816.1664687-4-Frank.Li@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 118c9402bb60..8a1f0a636848 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -1119,6 +1119,7 @@ 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;
@@ -1241,7 +1242,36 @@ 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;
