Re: [PATCH 1/4] mmc: sdhci-esdhc: Add SDHCI_QUIRK_32BIT_DMA_ADDR

From: Arnd Bergmann
Date: Thu May 04 2017 - 04:47:28 EST

On Wed, May 3, 2017 at 12:05 PM, BenoÃt ThÃbaudeau <benoit@xxxxxxxxxxx> wrote:
> The eSDHC can only DMA from 32-bit-aligned addresses.
> This fixes the following test cases of mmc_test:
> 11: Badly aligned write
> 12: Badly aligned read
> 13: Badly aligned multi-block write
> 14: Badly aligned multi-block read
> Signed-off-by: BenoÃt ThÃbaudeau <benoit@xxxxxxxxxxx>

Is this the right description? I thought that SDHCI_QUIRK_32BIT_DMA_ADDR
was for devices that cannot address high memory above 0xffffffff, rather than
requiring a specific alignment.

If this is indeed an address range problem rather than an alignment problem,
are you sure it is the SD controller that is wrong here, rather than having a
64-bit DMA capable SDHCI connected to a 32-bit parent bus? In the
latter case, the dma-ranges property in the parent bus should limit
the addressing, not the device.