Re: [PATCH 3/9] ARM: edma: Add function to manually trigger an EDMAchannel

From: Sekhar Nori
Date: Tue Jul 30 2013 - 01:19:16 EST


On Monday 29 July 2013 06:59 PM, Joel Fernandes wrote:
> Manual trigger for events missed as a result of splitting a
> scatter gather list and DMA'ing it in batches. Add a helper
> function to trigger a channel incase any such events are missed.
>
> Signed-off-by: Joel Fernandes <joelf@xxxxxx>
> ---
> arch/arm/common/edma.c | 21 +++++++++++++++++++++
> include/linux/platform_data/edma.h | 2 ++
> 2 files changed, 23 insertions(+)
>
> diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
> index 3567ba1..10995b2 100644
> --- a/arch/arm/common/edma.c
> +++ b/arch/arm/common/edma.c
> @@ -1236,6 +1236,27 @@ void edma_resume(unsigned channel)
> }
> EXPORT_SYMBOL(edma_resume);
>
> +int edma_manual_trigger(unsigned channel)

edma_trigger_channel() maybe? Brings consistency with
edma_alloc_channel() edma_free_channel() etc.

> +{
> + unsigned ctlr;
> + int j;
> + unsigned int mask;
> +
> + ctlr = EDMA_CTLR(channel);
> + channel = EDMA_CHAN_SLOT(channel);
> + mask = BIT(channel & 0x1f);
> +
> + j = channel >> 5;
> +
> + /* EDMA channels without event association */

May be actually check for no-event association before you trigger in
software? You can do that by looking at unused channel list, no?

> + edma_shadow0_write_array(ctlr, SH_ESR, j, mask);

edma_shadow0_write_array(ctlr, SH_ESR, channel >> 5, mask) is no less
readable, but I leave it to you.

Thanks,
Sekhar

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