On Mon, 13 May 2019 at 11:16, Neil Armstrong <narmstrong@xxxxxxxxxxxx> wrote:
>
> On the Amlogic G12A SoC family, (only) the SDIO controller has a bug which
> makes any DDR access from the MMC controller fail.
>
> Add the amlogic,ddr-access-quirk property so signal this particular
> controller has this bug and needs a quirk to work properly.
>
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
> index 13e70409e8ac..f8914dab06c6 100644
> --- a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
> +++ b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
> @@ -22,6 +22,10 @@ Required properties:
> clock rate requested by the MMC core.
> - resets : phandle of the internal reset line
>
> +Optional properties:
> +- amlogic,ddr-access-quirk: set when HW cannot access the DDR memory, like on
> + the G12A SDIO controller.
As stated on the other patch, may I suggest to use DRAM instead of DDR.
Moreover, please mention that this is about the internal DMA support
of the controller.
> +
> Example:
>
> sd_emmc_a: mmc@70000 {
> --
> 2.21.0
>
Kind regards
Uffe
