| From | Ben Hutchings <> | Date | Sat, 13 Aug 2016 18:42:51 +0100 | Subject | [PATCH 3.16 178/305] usb: musb: Stop bulk endpoint while queue is rotated |
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3.16.37-rc1 review patch. If anyone has any objections, please let me know.
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From: Andrew Goodbody <andrew.goodbody@cambrionix.com>
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/usb/musb/musb_host.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -949,9 +949,15 @@ static void musb_bulk_nak_timeout(struct 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);
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