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

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

[Joshua Henderson]

From: Cristian Birsan <cristian.birsan@microchip.com>

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@microchip.com>
Signed-off-by: Joshua Henderson <joshua.henderson@microchip.com>
---
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))
 				goto finish;
 			else
 				dev_err(musb->controller, "error: rx_dma failed\n");
-- 
1.7.9.5

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

[Sergei Shtylyov]

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

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

> ---
> 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