Re: [PATCH v2 5/7] atmel-mci: Add experimental DMA support
From: Pierre Ossman
Date: Sun Oct 12 2008 - 04:44:21 EST
On Sun, 5 Oct 2008 18:21:28 +0200
Haavard Skinnemoen <haavard.skinnemoen@xxxxxxxxx> wrote:
> This adds support for DMA transfers through the generic DMA engine
> framework with the DMA slave extensions.
>
> The driver has been tested using mmc-block and ext3fs on several SD,
> SDHC and MMC+ cards. Reads and writes work fine, with read transfer
> rates up to 7.5 MiB/s on fast cards with debugging disabled.
>
> Unfortunately, the driver has been known to lock up from time to time
> with DMA enabled, so DMA support is currently optional and marked
> EXPERIMENTAL. However, I didn't see any problems while testing 13
> different cards (MMC, SD and SDHC of different brands and sizes), so I
> suspect the "Initialize BLKR before sending data transfer command" fix
> that was posted earlier fixed this as well.
>
> Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@xxxxxxxxx>
> ---
Looks good, but I assume the plan is to remove this Kconfig option once
you're confident it is stable?
--
-- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org
rdesktop, core developer http://www.rdesktop.org
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