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

From: Daniel Walker
Date: Wed Mar 23 2011 - 09:05:41 EST


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.

Daniel

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