Re: [PATCH 6/7] dw_dmac: check if controller supports LLP

Andy Shevchenko
2012-09-20T09:47:12Z

On Tue, 2012-09-18 at 12:43 +0530, viresh kumar wrote:
> On Mon, Sep 17, 2012 at 1:09 PM, Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > Some controllers have the reduced functionality where the LLP multi block
> > transfers are not supported. This patch introduces a check and refuses to deal
> > with such devices.
> >
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > ---
> > drivers/dma/dw_dmac.c | 35 ++++++++++++++++++++++++++++++++++-
> > drivers/dma/dw_dmac_regs.h | 4 ++++
> > 2 files changed, 38 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
> > index fdb7d5a..00958ad 100644
> > --- a/drivers/dma/dw_dmac.c
> > +++ b/drivers/dma/dw_dmac.c
> > @@ -647,6 +647,12 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
> > unsigned int dst_width;
> > u32 ctllo;
> >
> > + if (dwc->nollp) {
> > + dev_dbg(chan2dev(&dwc->chan),
> > + "channel doesn't support LLP transfers\n");
> > + return NULL;
> > + }
>
> But this could have been a single block request. Isn't it?
I think we could discard this comment in regard to comments on next
patch.

--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy