Subject: [PATCH v2] ARM: EDMA: Fix clearing of unused list for DT DMA resources

From: [email-masked] (Mark Jackson)
Date: Fri, 06 Sep 2013 20:13:07 +0100

On 23/08/13 20:53, Joel Fernandes wrote:
> HWMOD removal for MMC and Crypto is breaking edma_start as the events are
> being manually triggered due to unused channel list not being clear. Atleast
> breakage has been seen on these peripherals, but it is expected Audio (McASP)
> maybe breaking too.
> 
> This patch fixes the issue, by reading the "dmas" property from the DT node if
> it exists and clearing the bits in the unused channel list so that these channels
> are not manually triggered.
> 
> v2 changes:
> Reduced indendation by returning from if block.
> 
> Reviewed-by: Sekhar Nori <[email-masked]>
> Reported-by: Balaji T K <[email-masked]>
> Cc: Pantel Antoniou <[email-masked]>
> Signed-off-by: Joel Fernandes <[email-masked]>
> ---
> Note:
> Patch should go in for -rc cycle as it fixes existing crypto drivers.
> 
>  arch/arm/common/edma.c | 22 +++++++++++++++++++---
>  1 file changed, 19 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
> index 39ad030..3867e7e 100644
> --- a/arch/arm/common/edma.c
> +++ b/arch/arm/common/edma.c
> @@ -560,14 +560,30 @@ static int reserve_contiguous_slots(int ctlr, unsigned int id,
>  static int prepare_unused_channel_list(struct device *dev, void *data)
>  {
>  	struct platform_device *pdev = to_platform_device(dev);
> -	int i, ctlr;
> +	int i = 0, ctlr;
> +	u32 dma_chan;
> +	const __be32 *dma_chan_p;
> +	struct property *prop;
> +
> +	if (dev->of_node) {
> +		of_property_for_each_u32(dev->of_node, "dmas", prop,
> +					 dma_chan_p, dma_chan) {
> +			if (i++ & 1) {
> +				ctlr = EDMA_CTLR(dma_chan);
> +				clear_bit(EDMA_CHAN_SLOT(dma_chan),
> +					  edma_cc[ctlr]->edma_unused);
> +			}
> +		}
> +		return;

This should return something here, otherwise we get:-

arch/arm/common/edma.c: In function 'prepare_unused_channel_list':
arch/arm/common/edma.c:577:3: warning: 'return' with no value, in function returning non-void [-Wreturn-type]

Mark J.

> +	}
>  
> -	for (i = 0; i < pdev->num_resources; i++) {
> +	/* For non-OF case */
> +	for (; i < pdev->num_resources; i++) {
>  		if ((pdev->resource[i].flags & IORESOURCE_DMA) &&
>  				(int)pdev->resource[i].start >= 0) {
>  			ctlr = EDMA_CTLR(pdev->resource[i].start);
>  			clear_bit(EDMA_CHAN_SLOT(pdev->resource[i].start),
> -					edma_cc[ctlr]->edma_unused);
> +				  edma_cc[ctlr]->edma_unused);
>  		}
>  	}