Re: [PATCH 4/5] mmc: mxcmmc: enable DMA support on mpc512x

Sascha Hauer
2013-03-14T20:11:40Z

On Thu, Mar 14, 2013 at 05:40:53PM +0100, Anatolij Gustschin wrote:
> Add SDHC DMA channel description to the mpc512x device
> tree to enable slave channel requesting in the mxcmmc
> driver.
>
> mpc512x DMA engine doesn't support endianness conversion
> when reading/writing data from peripheral's FIFO, so we
> have to swap data buffers before each DMA write and after
> each DMA read transfer manually.
>
> Since chained SDHC DMA transfers are not supported on
> mpc512x, limit 'max_segs' tunable parameter to one and
> initialise it to 64 only when running on i.MX platforms.

They are also not supported on the older i.MX platforms. Shouldn't this
be handled in the DMA driver?

Sascha

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