From 7ba4a8aad2441531e9d434ef07312944c8cc91e4 Mon Sep 17 00:00:00 2001 From: Andrew Goodbody Date: Tue, 31 May 2016 10:05:27 -0500 Subject: [PATCH] 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 Signed-off-by: Bin Liu Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: adjust context, indentation] Signed-off-by: Ben Hutchings --- 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 c655c713abf4..f2b72681d0bc 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -1384,9 +1384,15 @@ static void musb_bulk_rx_nak_timeout(struct musb *musb, struct musb_hw_ep *ep) musb_ep_select(mbase, ep->epnum); 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); -- 2.30.2