linux-kernel - RE: [PATCH 3.12 105/123] usb: musb: cppi41: improve rx channel abort routine

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Date:	Mon, 29 Feb 2016 14:52:35 +0000
From:	"Liu [EP], Bin" <b-liu@...com>
To:	Jiri Slaby <jslaby@...e.cz>,
	"stable@...r.kernel.org" <stable@...r.kernel.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Oliver Neukum" <ONeukum@...e.com>,
	"Felipe Balbi (balbi@...nel.org)" <balbi@...nel.org>,
	"yegorslists@...glemail.com" <yegorslists@...glemail.com>
Subject: RE: [PATCH 3.12 105/123] usb: musb: cppi41: improve rx channel
 abort routine

Hi Jiri,

> -----Original Message-----
> From: Jiri Slaby [mailto:jslaby@...e.cz]
> Sent: Wednesday, October 28, 2015 8:54 AM
> To: stable@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org; Liu, Bin; Balbi, Felipe; Oliver Neukum; Jiri
> Slaby
> Subject: [PATCH 3.12 105/123] usb: musb: cppi41: improve rx channel abort
> routine
> 
> From: Bin Liu <b-liu@...com>
> 
> 3.12-stable review patch.  If anyone has any objections, please let me know.

It seems this backport missing the dependency 0149b07 upstream (usb: musb:
cppi41: correct the macro name EP_MODE_AUTOREG_*), which causes the micro
name mismatch.

Sorry for the late response, I just received the regression report.

Thanks,
-Bin.

> 
> ===============
> 
> commit cb83df77f3ec151d68a1b6be957207e6fc7b7f50 upstream.
> 
> 1. set AUTOREQ to NONE at the beginning of teardown;
> 
> 2. add delay for dma pipeline to drain;
> 
> 3. Do not set USB_TDOWN bit for RX teardown.
> 
>   The CPPI hw has an issue that when tearing down a RX channel, if
>   another RX channel is receiving data, the CPPI will lockup.
> 
>   To workaround the issue, do not set the CPPI TD bit. The steps before
>   this point ensures the CPPI channel will be torn down properly.
> 
> Signed-off-by: Bin Liu <b-liu@...com>
> Signed-off-by: Felipe Balbi <balbi@...com>
> Cc: Oliver Neukum <ONeukum@...e.com>
> Signed-off-by: Jiri Slaby <jslaby@...e.cz>
> ---
>  drivers/usb/musb/musb_cppi41.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/musb/musb_cppi41.c
> b/drivers/usb/musb/musb_cppi41.c index 77b475a43dad..1c9c626248fd 100644
> --- a/drivers/usb/musb/musb_cppi41.c
> +++ b/drivers/usb/musb/musb_cppi41.c
> @@ -507,10 +507,15 @@ static int cppi41_dma_channel_abort(struct
> dma_channel *channel)
>  		csr &= ~MUSB_TXCSR_DMAENAB;
>  		musb_writew(epio, MUSB_TXCSR, csr);
>  	} else {
> +		cppi41_set_autoreq_mode(cppi41_channel,
> EP_MODE_AUTOREQ_NONE);
> +
>  		csr = musb_readw(epio, MUSB_RXCSR);
>  		csr &= ~(MUSB_RXCSR_H_REQPKT | MUSB_RXCSR_DMAENAB);
>  		musb_writew(epio, MUSB_RXCSR, csr);
> 
> +		/* wait to drain cppi dma pipe line */
> +		udelay(50);
> +
>  		csr = musb_readw(epio, MUSB_RXCSR);
>  		if (csr & MUSB_RXCSR_RXPKTRDY) {
>  			csr |= MUSB_RXCSR_FLUSHFIFO;
> @@ -524,13 +529,14 @@ static int cppi41_dma_channel_abort(struct
> dma_channel *channel)
>  		tdbit <<= 16;
> 
>  	do {
> -		musb_writel(musb->ctrl_base, USB_TDOWN, tdbit);
> +		if (is_tx)
> +			musb_writel(musb->ctrl_base, USB_TDOWN, tdbit);
>  		ret = dmaengine_terminate_all(cppi41_channel->dc);
>  	} while (ret == -EAGAIN);
> 
> -	musb_writel(musb->ctrl_base, USB_TDOWN, tdbit);
> -
>  	if (is_tx) {
> +		musb_writel(musb->ctrl_base, USB_TDOWN, tdbit);
> +
>  		csr = musb_readw(epio, MUSB_TXCSR);
>  		if (csr & MUSB_TXCSR_TXPKTRDY) {
>  			csr |= MUSB_TXCSR_FLUSHFIFO;
> --
> 2.6.2