Re: [PATCH] mmc: tegra: Mark 64 bit dma broken on Tegra186

[Adrian Hunter]

On 08/09/17 22:48, Krishna Reddy wrote:
> SDHCI controllers on Tegra186 support 40 bit addressing.
> IOVA addresses are 48-bit wide on Tegra186.
> SDHCI host common code sets dma mask as either 32-bit or 64-bit.
> To avoid access issues when SMMU is enabled, disable 64-bit dma.
> 
> Signed-off-by: Krishna Reddy <vdumpa@xxxxxxxxxx>

Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

> ---
>  drivers/mmc/host/sdhci-tegra.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
> index 0cd6fa80db66..b877c13184c2 100644
> --- a/drivers/mmc/host/sdhci-tegra.c
> +++ b/drivers/mmc/host/sdhci-tegra.c
> @@ -422,7 +422,15 @@ static const struct sdhci_pltfm_data sdhci_tegra186_pdata = {
>  		  SDHCI_QUIRK_NO_HISPD_BIT |
>  		  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC |
>  		  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
> -	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
> +	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
> +		   /* SDHCI controllers on Tegra186 support 40-bit addressing.
> +		    * IOVA addresses are 48-bit wide on Tegra186.
> +		    * With 64-bit dma mask used for SDHCI, accesses can
> +		    * be broken. Disable 64-bit dma, which would fall back
> +		    * to 32-bit dma mask. Ideally 40-bit dma mask would work,
> +		    * But it is not supported as of now.
> +		    */
> +		   SDHCI_QUIRK2_BROKEN_64_BIT_DMA,
>  	.ops  = &tegra114_sdhci_ops,
>  };
>  
>