[PATCH 2/6] mpc512x_dma: fix the hanged transfer issue

[Grant Likely]

On Wed, Oct 27, 2010 at 01:52:56AM +0200, Ilya Yanok wrote:
> Current code clears interrupt active status _after_ submiting new
> transfers. This leaves a possibility of clearing the interrupt for this
> new transfer (if it is triggered fast enough) and thus lose this
> interrupt. We want to clear interrupt active status _before_ new
> transfers is submited and for current channel only.
> 
> Signed-off-by: Ilya Yanok <yanok at emcraft.com>
> Cc: Piotr Ziecik <kosmo at semihalf.com>

Merged for -next, thanks.

g.

> ---
>  drivers/dma/mpc512x_dma.c |    9 +++------
>  1 files changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
> index 1bc04aa..0717527 100644
> --- a/drivers/dma/mpc512x_dma.c
> +++ b/drivers/dma/mpc512x_dma.c
> @@ -276,6 +276,9 @@ static void mpc_dma_irq_process(struct mpc_dma *mdma, u32 is, u32 es, int off)
>  
>  		spin_lock(&mchan->lock);
>  
> +		out_8(&mdma->regs->dmacint, ch + off);
> +		out_8(&mdma->regs->dmacerr, ch + off);
> +
>  		/* Check error status */
>  		if (es & (1 << ch))
>  			list_for_each_entry(mdesc, &mchan->active, node)
> @@ -309,12 +312,6 @@ static irqreturn_t mpc_dma_irq(int irq, void *data)
>  	mpc_dma_irq_process(mdma, in_be32(&mdma->regs->dmaintl),
>  					in_be32(&mdma->regs->dmaerrl), 0);
>  
> -	/* Ack interrupt on all channels */
> -	out_be32(&mdma->regs->dmainth, 0xFFFFFFFF);
> -	out_be32(&mdma->regs->dmaintl, 0xFFFFFFFF);
> -	out_be32(&mdma->regs->dmaerrh, 0xFFFFFFFF);
> -	out_be32(&mdma->regs->dmaerrl, 0xFFFFFFFF);
> -
>  	/* Schedule tasklet */
>  	tasklet_schedule(&mdma->tasklet);
>  
> -- 
> 1.7.2.3
> 
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