Re: [PATCH v2] ARM: EDMA: Fix clearing of unused list for DT DMAresources

From: Mark Jackson
Date: Fri Sep 06 2013 - 15:13:36 EST


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 <nsekhar@xxxxxx>
> Reported-by: Balaji T K <balajitk@xxxxxx>
> Cc: Pantel Antoniou <panto@xxxxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Joel Fernandes <joelf@xxxxxx>
> ---
> 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);
> }
> }

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