Re: [PATCH v3 1/2] usb: musb: Fix DMA for host mode

From: Sergei Shtylyov
Date: Thu Feb 11 2016 - 12:42:22 EST


On 02/11/2016 06:58 PM, Joshua Henderson wrote:

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.

You're supposed to document your own changes above --- when you're pushing someone other's patch... in this minimalistic patch, the changes were so dramatic that you could have changed the authorship instead...

Signed-off-by: Cristian Birsan <cristian.birsan@xxxxxxxxxxxxx>
Signed-off-by: Joshua Henderson <joshua.henderson@xxxxxxxxxxxxx>

---
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 | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 795a45b..6a81066 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -2003,10 +2003,9 @@ 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))

Can be compressed to 2 lines.

[...]

Other than that, I'm content now. :-)

MBR, Sergei