[PATCH v2 1/2] usb: musb: Fix DMA for host mode

From: Joshua Henderson
Date: Mon Feb 08 2016 - 17:15:47 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>
---
Changes since v1:
- Don't add unecessary new variable. Just correct done.
---
drivers/usb/musb/musb_host.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 795a45b..6bef86f 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -2006,9 +2006,15 @@ void musb_host_rx(struct musb *musb, u8 epnum)
done = musb_rx_dma_in_inventra_cppi41(c, hw_ep, qh,
urb, xfer_len,
iso_err);
- if (done)
+ if (done) {
+ /* Don't call msub_advance_schedule()
+ * immediately after receiving an endpoint RX
+ * interrupt without waiting for the DMA
+ * transfer to complete.
+ */
+ done = false;
goto finish;
- else
+ } else
dev_err(musb->controller, "error: rx_dma failed\n");
}

--
1.7.9.5