Re: [PATCH v2] mmc: sdhci-of-esdhc: set proper dma mask for ls104x chips

[Ulf Hansson]

On 4 July 2018 at 13:34, Laurentiu Tudor <laurentiu.tudor@xxxxxxx> wrote:
> SDHCI controller in ls1043a and ls1046a generate 40-bit wide addresses
> when doing DMA. Make sure that the corresponding dma mask is correctly
> configured.
>
> Context: when enabling smmu on these chips the following problem is
> encountered: the smmu input address size is 48 bits so the dma mappings
> for sdhci end up 48-bit wide. However, on these chips sdhci only use
> 40-bits of that address size when doing dma.
> So you end up with a 48-bit address translation in smmu but the device
> generates transactions with clipped 40-bit addresses, thus smmu context
> faults are triggered. Setting up the correct dma mask fixes this
> situation.
>
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>

Thanks, re-placed v1 with v2 on my next branch.

Kind regards
Uffe

> ---
> Changes in v2:
>  - updated commit log with some context
>
>  drivers/mmc/host/sdhci-of-esdhc.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
> index 4ffa6b173a21..8332f56e6c0d 100644
> --- a/drivers/mmc/host/sdhci-of-esdhc.c
> +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> @@ -22,6 +22,7 @@
>  #include <linux/sys_soc.h>
>  #include <linux/clk.h>
>  #include <linux/ktime.h>
> +#include <linux/dma-mapping.h>
>  #include <linux/mmc/host.h>
>  #include "sdhci-pltfm.h"
>  #include "sdhci-esdhc.h"
> @@ -427,6 +428,11 @@ static void esdhc_of_adma_workaround(struct sdhci_host *host, u32 intmask)
>  static int esdhc_of_enable_dma(struct sdhci_host *host)
>  {
>         u32 value;
> +       struct device *dev = mmc_dev(host->mmc);
> +
> +       if (of_device_is_compatible(dev->of_node, "fsl,ls1043a-esdhc") ||
> +           of_device_is_compatible(dev->of_node, "fsl,ls1046a-esdhc"))
> +               dma_set_mask_and_coherent(dev, DMA_BIT_MASK(40));
>
>         value = sdhci_readl(host, ESDHC_DMA_SYSCTL);
>         value |= ESDHC_DMA_SNOOP;
> --
> 2.17.1
>