Tony,
> -----Original Message-----
> From: Tony Lindgren [mailto:[email protected]]
> Sent: Monday, October 19, 2009 10:54 PM
> To: Shilimkar, Santosh
> Cc: [email protected]; S, Venkatraman; Hari n; Jarkko
> Nikula
> Subject: Re: [PATCH v2] ARM: OMAP: SDMA: Fix omap_stop_dma() API for
> channel linking
>
> * Santosh Shilimkar <[email protected]> [091015 00:07]:
> > OMAP sDMA driver API omap_stop_dma() doesn't really stop the dma
> when used
> > in linking scenario. This patch fixes the same.
> >
> > Signed-off-by: Santosh Shilimkar <[email protected]>
> > Signed-off-by: Venkatraman S <[email protected]>
> > Reviewed-By: Tony Lindgren <[email protected]>
> > CC: Hari n <[email protected]>
> > CC: Jarkko Nikula <[email protected]>
> > ---
> > arch/arm/plat-omap/dma.c | 5 +++++
> > 1 files changed, 5 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
> > index fd3154a..1c933b4 100644
> > --- a/arch/arm/plat-omap/dma.c
> > +++ b/arch/arm/plat-omap/dma.c
> > @@ -987,6 +987,11 @@ void omap_stop_dma(int lch)
> > /* Mark the current channel */
> > dma_chan_link_map[cur_lch] = 1;
> >
> > + /* Disable the DMA channel */
> > + l = dma_read(CCR(lch));
> > + l &= ~OMAP_DMA_CCR_EN;
> > + dma_write(l, CCR(lch));
> > +
> > disable_lnk(cur_lch);
> >
> > next_lch = dma_chan[cur_lch].next_lch;
>
> Hmm, I'm thinking it should be like this instead to also clear
> the dma_chan[lch].flags instead of returning before that.
>
> Can you try this with your testcase?
This works too. OMAP1 doesn't support channel linking so this is fine. In case
it was, then it would have been an issue.
> diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
> index 0eb676d..b53125f 100644
> --- a/arch/arm/plat-omap/dma.c
> +++ b/arch/arm/plat-omap/dma.c
> @@ -978,6 +978,14 @@ void omap_stop_dma(int lch)
> {
> u32 l;
>
> + /* Disable all interrupts on the channel */
> + if (cpu_class_is_omap1())
> + dma_write(0, CICR(lch));
> +
> + l = dma_read(CCR(lch));
> + l &= ~OMAP_DMA_CCR_EN;
> + dma_write(l, CCR(lch));
> +
> if (!omap_dma_in_1510_mode() && dma_chan[lch].next_lch != -1)
> {
> int next_lch, cur_lch = lch;
> char dma_chan_link_map[OMAP_DMA4_LOGICAL_DMA_CH_COUNT];
> @@ -995,18 +1003,8 @@ void omap_stop_dma(int lch)
> next_lch = dma_chan[cur_lch].next_lch;
> cur_lch = next_lch;
> } while (next_lch != -1);
> -
> - return;
> }
>
> - /* Disable all interrupts on the channel */
> - if (cpu_class_is_omap1())
> - dma_write(0, CICR(lch));
> -
> - l = dma_read(CCR(lch));
> - l &= ~OMAP_DMA_CCR_EN;
> - dma_write(l, CCR(lch));
> -
> dma_chan[lch].flags &= ~OMAP_DMA_ACTIVE;
> }
> EXPORT_SYMBOL(omap_stop_dma);
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