[U-Boot] [PATCH v3 03/10] sunxi: Remove mmc DMA support
Siarhei Siamashka
siarhei.siamashka at gmail.com
Wed Jul 23 19:35:50 CEST 2014
On Mon, 9 Jun 2014 11:36:55 +0200
Hans de Goede <hdegoede at redhat.com> wrote:
> The DMA code in sunxi_mmc.c is broken. mmc_trans_data_by_dma() allocates the
> dma descriptors on the stack, and then exits while the dma transfer is in
> progress, so the dma engine is reading stack memory which at that point may
> be re-used. So far we've gotten away with this by luck, but recent u-boot
> changes have shifted the stack start address by 16 bytes, which combined
> with dma alignment now exposes this problem.
>
> Since we end up just busy waiting for the dma engine anyway, this commit
> fixes things by simply removing the dma code, resulting in smaller bug-free
> code.
>
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> Acked-by: Ian Campbell <ijc at hellion.org.uk>
Acked-by: Siarhei Siamashka <siarhei.siamashka at gmail.com>
Was it a good idea to keep v2014.07 release relying on luck without
this patch?
--
Best regards,
Siarhei Siamashka
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