[U-Boot] [PATCH] usb: musb: only write CLRDATATOG when appropriate

[Sergei Shtylyov <sshtylyov@mvista.com>]

Hello.

Mike Frysinger wrote:

> From: Bryan Wu <bryan.wu@analog.com>

> This is a change similar to what is already in the Linux driver.  We
> should only program the CLRDATATOG bit when the current mode indicates
> that it is needed.

> Signed-off-by: Bryan Wu <bryan.wu@analog.com>
> Signed-off-by: Cliff Cai <cliff.cai@analog.com>
> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
> ---
> Note: can someone give this a spin on a non-Blackfin platform to make
>       sure this doesn't break things ?

>  drivers/usb/musb/musb_hcd.c |   23 ++++++++++++++++-------
>  1 files changed, 16 insertions(+), 7 deletions(-)

> diff --git a/drivers/usb/musb/musb_hcd.c b/drivers/usb/musb/musb_hcd.c
> index dd2aa7f..dd66275 100644
> --- a/drivers/usb/musb/musb_hcd.c
> +++ b/drivers/usb/musb/musb_hcd.c
> @@ -144,19 +144,28 @@ static void write_toggle(struct usb_device *dev, u8 ep, u8 dir_out)
>  	u16 csr;
>  
>  	if (dir_out) {
> -		if (!toggle)
> -			writew(MUSB_TXCSR_CLRDATATOG, &musbr->txcsr);
> -		else {
> -			csr = readw(&musbr->txcsr);
> +		csr = readw(&musbr->txcsr);
> +		if (!toggle) {
> +			if (csr & MUSB_TXCSR_MODE)
> +				csr = MUSB_TXCSR_CLRDATATOG;
> +			else
> +				csr = 0;
> +			writew(csr, &musbr->txcsr);
> +		} else {
>  			csr |= MUSB_TXCSR_H_WR_DATATOGGLE;
>  			writew(csr, &musbr->txcsr);
>  			csr |= (toggle << MUSB_TXCSR_H_DATATOGGLE_SHIFT);
>  			writew(csr, &musbr->txcsr);
>  		}
>  	} else {
> -		if (!toggle)
> -			writew(MUSB_RXCSR_CLRDATATOG, &musbr->rxcsr);
> -		else {
> +		if (!toggle) {
> +			csr = readw(&musbr->txcsr);
> +			if (csr & MUSB_TXCSR_MODE)
> +				csr = MUSB_RXCSR_CLRDATATOG;

    Clearing RXCSR when FIFO is in TX mode?

> +			else
> +				csr = 0;
> +			writew(csr, &musbr->rxcsr);
> +		} else {
>  			csr = readw(&musbr->rxcsr);
>  			csr |= MUSB_RXCSR_H_WR_DATATOGGLE;
>  			writew(csr, &musbr->rxcsr);

WBR, Sergei