RE: [PATCH] ARM: OMAP: SDMA: Fix omap_stop_dma() API for channel linking

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



> -----Original Message-----
> From: Tony Lindgren [mailto:tony@xxxxxxxxxxx]
> Sent: Wednesday, October 14, 2009 10:36 PM
> To: Shilimkar, Santosh
> Cc: linux-omap@xxxxxxxxxxxxxxx; S, Venkatraman; Hari n; Jarkko Nikula
> Subject: Re: [PATCH] ARM: OMAP: SDMA: Fix omap_stop_dma() API for channel
> linking
> 
> * Santosh Shilimkar <santosh.shilimkar@xxxxxx> [091013 23:14]:
> > OMAP sDMA driver API omap_stop_dma() doesn't really stop the dma when
> used
> > in linking scenario. This patch fixes the same.
> 
> To me it looks like this will break things for omap1 as the DMA channel
> interrupt is not disabled first. I guess the fix is to move the
> "Disable all interrupts on the channel" part above clearing the
> link mappings.
Indeed it will break OMAP1. Initially I thought of putting this change at this place so that it takes care of both normal and linking scenario. 

I will rework this and send v2.

> This fix should be tested in linux-omap before we send this to mainline.
Yes ofcourse. That what I meant by merge.

> > Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> > Signed-off-by: Venkatraman S <svenkatr@xxxxxx>
> > CC: Hari n <hari.zoom@xxxxxxxxx>
> > CC: Jarkko Nikula <jhnikula@xxxxxxxxx>
> > ---
> >  arch/arm/plat-omap/dma.c |    9 +++++----
> >  1 files changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
> > index fd3154a..633c123 100644
> > --- a/arch/arm/plat-omap/dma.c
> > +++ b/arch/arm/plat-omap/dma.c
> > @@ -975,6 +975,11 @@ void omap_stop_dma(int lch)
> >  {
> >  	u32 l;
> >
> > +	/* Disable the DMA channel */
> > +	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];
> > @@ -1000,10 +1005,6 @@ void omap_stop_dma(int lch)
> >  	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);
> > --
> > 1.5.4.7
> >
Regards,
Santosh
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Arm (vger)]     [ARM Kernel]     [ARM MSM]     [Linux Tegra]     [Linux WPAN Networking]     [Linux Wireless Networking]     [Maemo Users]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Trails]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux