RE: [RFC] mmc: msm_sdcc: Use SPS BAM as DMA engine

[Subhash Jadavani]

> -----Original Message-----
> From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Daniel Walker
> Sent: Wednesday, March 23, 2011 6:36 PM
> To: Subhash Jadavani
> Cc: cjb@xxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; linux-arm-
> msm@xxxxxxxxxxxxxxx; davidb@xxxxxxxxxxxxxx; bryanh@xxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [RFC] mmc: msm_sdcc: Use SPS BAM as DMA engine
> 
> On Fri, 2011-03-18 at 18:54 +0530, Subhash Jadavani wrote:
> > On recent MSMs, ADM (Data Mover) HW is not present
> > which means existing SDCC driver can perform data
> > transfer in PIO (peripheral IO) mode only.
> > But PIO mode requires lot of CPU attention which
> > would mean consuming extra CPU MIPS.
> >
> > As a replacement on these recent MSMs, there is
> > a new DMA HW engine named SPS-BAM (as part of
> > Smart Peripheral System of MSM) is added for
> > data movement between SDCC core and system memory.
> >
> > This patch has done changes in existing MSM SDCC
> > driver for using SPS-BAM as DMA engine.
> 
> 1300+ lines of code might warrant more of a description .. In the
> subject you say "DMA engine" but does this use drivers/dma/dmaengine.c
> ?
> 
> > Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
> > ---
> >  drivers/mmc/host/Kconfig        |   10 +
> >  drivers/mmc/host/Makefile       |    1 +
> >  drivers/mmc/host/msm_sdcc.c     |  929
> +++++++++++++++++++++++++++++++++++++--
> >  drivers/mmc/host/msm_sdcc.h     |   47 ++
> >  drivers/mmc/host/msm_sdcc_dml.c |  303 +++++++++++++
> >  drivers/mmc/host/msm_sdcc_dml.h |  120 +++++
> >  6 files changed, 1374 insertions(+), 36 deletions(-)
> >  create mode 100644 drivers/mmc/host/msm_sdcc_dml.c
> >  create mode 100644 drivers/mmc/host/msm_sdcc_dml.h
> 
> I'd do at least two patches. One that adds msm_sdcc_dml.[ch] and one
> that modifies msm_sdcc.[ch] and the Kconfig and Makefile.

Yes, I can do that. Will make sure to separate it in 2 patches when I upload v2.

Thanks,
Subhash

> 
> Daniel
> 
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