• Benoît Thébaudeau's avatar
    mmc: sdhci-esdhc-imx: Remove the ENGcm07207 workaround · 667123f6
    Benoît Thébaudeau authored
    The SDHCI_QUIRK_NO_MULTIBLOCK quirk was used as a workaround for the
    ENGcm07207 erratum. However, it caused excruciatingly slow SD transfers
    (300 kB/s on average), and this erratum actually does not imply that
    multiple-block transfers are not supported, so this was overkill.
    
    The suggested workaround for this erratum is to set SYSCTL.RSTA, but the
    simple DAT line software reset (which resets the DMA circuit among
    others) triggered by sdhci_finish_data() in case of errors seems to be
    sufficient. Indeed, generating errors in a controlled manner on i.MX25
    using the FEVT register right in the middle of read data transfers
    without this quirk shows that nothing is written to the buffer by the
    eSDHC past CMD12, and no extra Auto CMD12 is sent with AC12EN set, so
    the data transfers on AHB are properly aborted. For write data
    transfers, neither extra data nor extra Auto CMD12 is sent, as expected.
    Moreover, after intensive stress tests on i.MX25, removing
    SDHCI_QUIRK_NO_MULTIBLOCK seems to be safe.
    
    SDHCI_QUIRK_BROKEN_ADMA has nothing to do with ENGcm07207, so set
    ESDHC_FLAG_ERR004536 for the devices that had ESDHC_FLAG_ENGCM07207 set
    in order to continue getting SDHCI_QUIRK_BROKEN_ADMA.
    Signed-off-by: default avatarBenoît Thébaudeau <benoit@wsystem.com>
    Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
    Reviewed-by: default avatarFabio Estevam <fabio.estevam@nxp.com>
    Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
    667123f6
sdhci-esdhc-imx.c 41.7 KB