[U-Boot] [RFC PATCH v3] usb: limit USB_MAX_XFER_BLK to 256

[Marcel Ziswiler]

From: Peng Fan <peng.fan at nxp.com>

For Some USB mass storage devices, such as:
"
 - Kingston DataTraveler 2.0 001D7D06CF09B04199C7B3EA
 - Class: (from Interface) Mass Storage
 - PacketSize: 64  Configurations: 1
 - Vendor: 0x0930  Product 0x6545 Version 1.16
"
When `usb read 0x80000000 0 0x2000`, we met
"EHCI timed out on TD - token=0x80008d80".

The devices does not support scsi VPD page, we are not able
to get the maximum transfer length for READ(10)/WRITE(10).

So we limit this to 256 blocks as READ(6).

Signed-off-by: Peng Fan <peng.fan at nxp.com>
Acked-by: Marcel Ziswiler <marcel.ziswiler at toradex.com>
(cherry picked from commit df0052575b2bc9d66ae73584768e1a457ed5d914)

Signed-off-by: Marcel Ziswiler <marcel at ziswiler.com>

---
This comes from NXP's downstream and has proven to tremendously improve
the situation with those odd USB mass storage aka memory sticks. This is
why I post it here asking whether or not this may be something
benefiting more people. Any feedback and suggestions are welcome.

Changes in v3:
- Drop the reference to the NXP internal MLK-xxx tracking number as
  suggested by Peng.

Changes in v2:
- Fixed spelling in comment as suggested by Igor.

 common/usb_storage.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/common/usb_storage.c b/common/usb_storage.c
index 8c889bb1a6..4e284645f5 100644
--- a/common/usb_storage.c
+++ b/common/usb_storage.c
@@ -949,7 +949,11 @@ static void usb_stor_set_max_xfer_blk(struct usb_device *udev,
 	 * there is enough free heap space left, but the SCSI READ(10) and
 	 * WRITE(10) commands are limited to 65535 blocks.
 	 */
-	blk = USHRT_MAX;
+	/*
+	 * Some USB mass storage devices have issues, limiting this to 256
+	 * fixes this.
+	 */
+	blk = 256;
 #else
 	blk = 20;
 #endif
-- 
2.20.1