[PATCH v4 1/2] usb: musb: Fix DMA for host mode

From: Joshua Henderson
Date: Fri Feb 19 2016 - 11:41:07 EST


From: Cristian Birsan <cristian.birsan@xxxxxxxxxxxxx>

Commit ac33cdb16681 ("usb: musb: Remove ifdefs for musb_host_rx in
musb_host.c part5") introduces a problem setting DMA host mode.

This commit fixes the done condition that advances the musb schedule.
Without this patch the the msub_advance_schedule() is called immediately
after receiving an endpoint RX interrupt without waiting for the DMA
transfer to complete. As a consequence when the dma complete interrupt
arrives the in_qh member of hw_ep is already null an the musb_host_rx()
exits on !urb error case.

Signed-off-by: Cristian Birsan <cristian.birsan@xxxxxxxxxxxxx>
Signed-off-by: Joshua Henderson <joshua.henderson@xxxxxxxxxxxxx>
Tested-by: Ladislav Michl <ladis@xxxxxxxxxxxxxx>
---
Changes since v3:
- Fix formatting to 2 lines.
Changes since v2:
- Put function call in if condition.
Changes since v1:
- Don't add unecessary new variable. Just correct done.
---
drivers/usb/musb/musb_host.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 795a45b..75c89b4 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -2003,10 +2003,8 @@ void musb_host_rx(struct musb *musb, u8 epnum)
qh->offset,
urb->transfer_buffer_length);

- done = musb_rx_dma_in_inventra_cppi41(c, hw_ep, qh,
- urb, xfer_len,
- iso_err);
- if (done)
+ if (musb_rx_dma_in_inventra_cppi41(c, hw_ep, qh, urb,
+ xfer_len, iso_err))
goto finish;
else
dev_err(musb->controller, "error: rx_dma failed\n");
--
1.7.9.5