From: Andrew Goodbody <andrew.goodbody@xxxxxxxxxxxxxx>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
commit 7b2c17f829545df27a910e8d82e133c21c9a8c9c upstream.
Ensure that the endpoint is stopped by clearing REQPKT before
clearing DATAERR_NAKTIMEOUT before rotating the queue on the
dedicated bulk endpoint.
This addresses an issue where a race could result in the endpoint
receiving data before it was reprogrammed resulting in a warning
about such data from musb_rx_reinit before it was thrown away.
The data thrown away was a valid packet that had been correctly
ACKed which meant the host and device got out of sync.
Signed-off-by: Andrew Goodbody <andrew.goodbody@xxxxxxxxxxxxxx>
Signed-off-by: Bin Liu <b-liu@xxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/usb/musb/musb_host.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index d73cda3591aa..7a149719d495 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -951,9 +951,15 @@ static void musb_bulk_nak_timeout(struct musb *musb, struct musb_hw_ep *ep,
if (is_in) {
dma = is_dma_capable() ? ep->rx_channel : NULL;
- /* clear nak timeout bit */
+ /*
+ * Need to stop the transaction by clearing REQPKT first
+ * then the NAK Timeout bit ref MUSBMHDRC USB 2.0 HIGH-SPEED
+ * DUAL-ROLE CONTROLLER Programmer's Guide, section 9.2.2
+ */
rx_csr = musb_readw(epio, MUSB_RXCSR);
rx_csr |= MUSB_RXCSR_H_WZC_BITS;
+ rx_csr &= ~MUSB_RXCSR_H_REQPKT;
+ musb_writew(epio, MUSB_RXCSR, rx_csr);
rx_csr &= ~MUSB_RXCSR_DATAERROR;
musb_writew(epio, MUSB_RXCSR, rx_csr);
--
2.9.0
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