usb: musb: Stop bulk endpoint while queue is rotated

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@cambrionix.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index d73cda3591aa408952161eec1a86d9450f0f4278..7a149719d4950e21341470337e9aef31edc1b07a 100644 (file)
--- 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);