[U-Boot] [PATCH] rockchip: px30: enable fifo mode for both emmc and sdmmc on evb

[Philipp Tomsich]

Heiko,

> On 19.11.2019, at 11:03, Heiko Stuebner <heiko at sntech.de> wrote:
> 
> From: Heiko Stuebner <heiko.stuebner at theobroma-systems.com>
> 
> As part of loading trustedfirmware, the SPL is required to place portions
> of code into the socs sram but the mmc controllers can only do dma
> transfers into the regular memory, not sram.
> 
> The results of this are not directly visible in u-boot itself, but
> manifest as security-relate cpu aborts during boot of for example Linux.
> 
> There were a number of attempts to solve this elegantly but so far
> discussion is still ongoing, so to make the board at least boot correctly
> put both mmc controllers into fifo-mode, which also circumvents the
> issue for now.
> 
> Signed-off-by: Heiko Stuebner <heiko.stuebner at theobroma-systems.com>
> ---
> arch/arm/dts/px30-evb-u-boot.dtsi | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/dts/px30-evb-u-boot.dtsi b/arch/arm/dts/px30-evb-u-boot.dtsi
> index 3de9c7068e..27b8364e6c 100644
> --- a/arch/arm/dts/px30-evb-u-boot.dtsi
> +++ b/arch/arm/dts/px30-evb-u-boot.dtsi
> @@ -31,12 +31,15 @@
> &sdmmc {
> 	u-boot,dm-pre-reloc;
> 
> -	/* temporary till I find out why dma mode doesn't work */
> +	/* mmc to sram can't do dma, prevent aborts transfering TF-A parts */
> 	fifo-mode;

Could you add a u-boot,spl-fifo-mode property to the driver?
Otherwise we force the controllers back to fifo-mode even for full U-Boot with
the associated performance impact.

Thanks,
Philipp.

> };
> 
> &emmc {
> 	u-boot,dm-pre-reloc;
> +
> +	/* mmc to sram can't do dma, prevent aborts transfering TF-A parts */
> +	fifo-mode;
> };
> 
> &grf {
> -- 
> 2.24.0
>