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    SubjectRe: [PATCH 16/18] dmaengine/ambhe rest oa-pl08x: Add support for sg len greater than one for slave transfers
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    On Fri, 2011-09-09 at 03:24 +0530, Vinod Koul wrote:
    > On Thu, 2011-09-08 at 12:29 +0200, Linus Walleij wrote:
    > > On Thu, Sep 8, 2011 at 5:50 AM, Viresh Kumar <viresh.kumar@st.com> wrote:
    > >
    > > > If i am getting this clearly, the concern is "why to queue separate transfers for
    > > > individual sg's? Better would be to prepare the complete list at once and
    > > > start the transfer, so that DMA stops only after finishing all sg's
    > > > passed from user." Is this what you are pointing at?
    > >
    > > Yes.
    > >
    > > > If yes, then the same is done in this patch too. An array for llis is allocated at
    > > > the start, then for each sg i prepare lli list from this array. Last lli from one sg
    > > > is followed by first lli from next sg. And so i get a continuous chain of llis.
    > >
    > > OK so I guess I was lost in the code ...
    > >
    > > So this is mainy cached as txd->dsg_list so you can quickly retrieve the
    > > number of bytes pending in the LLI by traversing that sglist.
    > >
    > > This is better than what the coh901318 does, because that driver
    > > resorts to going into the physical LLIs themselves to retrieve this
    > > info.
    > >
    > > It also seems like this will play nice with Per Forlin's MMC
    > > speed-up patches, so that will become effective for your MMC
    > > usecases.
    > >
    > > Now I really like this patch.
    > >
    > > Sorry for being such a slow learner!
    > > Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
    > Okay, great. I will check the rest of the series (i think 3 patches) and
    > apply then next week.
    Applied the remaining two patches for the series to my next

    --
    ~Vinod



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