[PATCH 4.4 12/93] usb: musb: fix DMA for host mode

From: Greg Kroah-Hartman
Date: Thu Oct 06 2016 - 04:51:21 EST

4.4-stable review patch. If anyone has any objections, please let me know.


From: Cristian Birsan <cristian.birsan@xxxxxxxxxxxxx>

commit 4c2ba0c67394514f3f75c660c9f5d02e66a7efd4 upstream.

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

The musb_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. Fix the done condition that advances the musb schedule.

Signed-off-by: Cristian Birsan <cristian.birsan@xxxxxxxxxxxxx>
Signed-off-by: Joshua Henderson <joshua.henderson@xxxxxxxxxxxxx>
Tested-by: Ladislav Michl <ladis@xxxxxxxxxxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxxxxxx>
Cc: Tony Lindgren <tony@xxxxxxxxxxx>
Cc: Adam Ford <aford173@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/usb/musb/musb_host.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -2008,10 +2008,8 @@ void musb_host_rx(struct musb *musb, u8

- 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;
dev_err(musb->controller, "error: rx_dma failed\n");