Re: [PATCH v2] dma: fix scope of errata i88 upto 3430ES1.0

[Tony Lindgren <tony@atomide.com>]

* Venkatraman S <svenkatr@ti.com> [100419 03:47]:
> Hi Tony,
> > Venkatraman S <svenkatr@ti.com> wrote:
> > From 2799506180649cbb61d24cf2b4171425b2e1fa80 Mon Sep 17 00:00:00 2001
> > From: Venkatraman S <svenkatr@ti.com>
> > Date: Mon, 5 Apr 2010 20:56:27 +0530
> > Subject: [PATCH] dma: fix scope of errata i88 upto 3430ES1.0
> >
> > DMA errata for special end of block programming is applicable
> > only for OMAP2430 & OMAP3430 ES1.0.
> > This patch does the necessary checks before the workaround
> > is applied. Tested on 3430 SDP
> >
> > Signed-off-by: Thara Gopinath <thara@ti.com>
> > Signed-off-by: Venkatraman S <svenkatr@ti.com>
> > Reviewed-by: Shilimkar Santosh <santosh.shilimkar@ti.com>
> > ---
> > From v1, removed the redundant omap3430() check
> >
> >  arch/arm/plat-omap/dma.c |   20 ++++++++++++--------
> >  1 files changed, 12 insertions(+), 8 deletions(-)
> >
> > diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
> > index 2ab224c..a9b480a 100644
> > --- a/arch/arm/plat-omap/dma.c
> > +++ b/arch/arm/plat-omap/dma.c
> > @@ -1663,14 +1663,17 @@ int omap_stop_dma_chain_transfers(int chain_id)
> >        channels = dma_linked_lch[chain_id].linked_dmach_q;
> >
> >        /*
> > -        * DMA Errata:
> > -        * Special programming model needed to disable DMA before end of block
> > +        * DMA Errata: i88
> > +        * Special programming model needed
> > +        * to disable DMA before end of block
> >         */
> >        sys_cf = dma_read(OCP_SYSCONFIG);
> > -       l = sys_cf;
> > -       /* Middle mode reg set no Standby */
> > -       l &= ~((1 << 12)|(1 << 13));
> > -       dma_write(l, OCP_SYSCONFIG);
> > +       if (cpu_is_omap2430() || (omap_rev() == OMAP3430_REV_ES1_0)) {
> > +               l = sys_cf;
> > +               /* Middle mode reg set no Standby */
> > +               l &= ~((1 << 12)|(1 << 13));
> > +               dma_write(l, OCP_SYSCONFIG);
> > +       }
> >
> >        for (i = 0; i < dma_linked_lch[chain_id].no_of_lchs_linked; i++) {
> >

What about other omaps? It seems that we're currently doing the workaround
for all omaps. Seems like "Tested on 3430 SDP" is not quite safe enough
for making change that might affect other omaps.

Tony


> > @@ -1689,8 +1692,9 @@ int omap_stop_dma_chain_transfers(int chain_id)
> >        /* Reset the Queue pointers */
> >        OMAP_DMA_CHAIN_QINIT(chain_id);
> >
> > -       /* Errata - put in the old value */
> > -       dma_write(sys_cf, OCP_SYSCONFIG);
> > +       /* Errata: put back the old value */
> > +       if (cpu_is_omap2430() || (omap_rev() == OMAP3430_REV_ES1_0))
> > +               dma_write(sys_cf, OCP_SYSCONFIG);
> >
> >        return 0;
> >  }
> > --
> > 1.6.3.3
> >
> 
> If there are no other concerns about this patch, can you please include it ?
> Many thanks,
> Venkat.
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