Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1635479

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

From Arnd Bergmann <arnd@arndb.de>
Newsgroups linux.kernel
Subject Re: [PATCH 1/4] mmc: sdhci-esdhc: Add SDHCI_QUIRK_32BIT_DMA_ADDR
Date 2017-05-04 10:50 +0200
Message-ID <tDkCt-12n-1@gated-at.bofh.it> (permalink)
References <tCZy1-3Rz-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


On Wed, May 3, 2017 at 12:05 PM, Benoît Thébaudeau <benoit@wsystem.com> 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: Benoît Thébaudeau <benoit@wsystem.com>

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.

      Arnd

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread


Thread

[PATCH 1/4] mmc: sdhci-esdhc: Add SDHCI_QUIRK_32BIT_DMA_ADDR Benoît Thébaudeau <benoit@wsystem.com> - 2017-05-03 12:20 +0200
  [PATCH 4/4] mmc: sdhci-esdhc-imx: Remove the ENGcm07207 workaround Benoît Thébaudeau <benoit@wsystem.com> - 2017-05-03 12:20 +0200
  [PATCH 3/4] mmc: sdhci-esdhc-imx: Allow all supported prescaler values Benoît Thébaudeau <benoit@wsystem.com> - 2017-05-03 12:20 +0200
  Re: [PATCH 1/4] mmc: sdhci-esdhc: Add SDHCI_QUIRK_32BIT_DMA_ADDR Arnd Bergmann <arnd@arndb.de> - 2017-05-04 10:50 +0200
    Re: [PATCH 1/4] mmc: sdhci-esdhc: Add SDHCI_QUIRK_32BIT_DMA_ADDR Benoît Thébaudeau <benoit@wsystem.com> - 2017-05-04 11:10 +0200
      Re: [PATCH 1/4] mmc: sdhci-esdhc: Add SDHCI_QUIRK_32BIT_DMA_ADDR Arnd Bergmann <arnd@arndb.de> - 2017-05-04 11:40 +0200

csiph-web