[PATCH v2 0/1] Enable ddr modes on emmc2 of Raspberry Pi 4 B

[PATCH v2 0/1] Enable ddr modes on emmc2 of Raspberry Pi 4 B

[Tobias Schramm]

Currently  eMMC storage attached to a Pi 4 is running in single data
rate mode only. However the controller used supports dual data rate
modes. This patch enables ddr modes for mmc storage.

I've verified that there are no issues transferring data in ddr mode
using multiple eMMC modules from different vendors.
Additionally I've checked signal integrity on the data lines at the
micro SD card slot and did not find any issues there either.

This is v2 of this patch. The sd-uhs-ddr50 property present in the
initial version of the patch is not required and was removed.

Changelog:
 v2: Remove sd-uhs-ddr50 property

Tobias Schramm (1):
  ARM: dts: bcm2711: Enable ddr modes on emmc2 controller

 arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 1 +
 1 file changed, 1 insertion(+)

-- 
2.28.0

[PATCH v2 1/1] ARM: dts: bcm2711: Enable ddr modes on emmc2 controller

[Tobias Schramm]

This commit enables ddr modes for eMMC storage on emmc2.
The bcm2711 supports eMMC storage using ddr modes. The board
layout of the Raspberry Pi 4 supports them, too.

Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
---
 arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
index 222d7825e1ab..1851efebe9c6 100644
--- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
+++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
@@ -191,6 +191,7 @@ &emmc2 {
 	vqmmc-supply = <&sd_io_1v8_reg>;
 	vmmc-supply = <&sd_vcc_reg>;
 	broken-cd;
+	mmc-ddr-3_3v;
 	status = "okay";
 };
 
-- 
2.28.0

Re: [PATCH v2 1/1] ARM: dts: bcm2711: Enable ddr modes on emmc2 controller

[Stefan Wahren]

Hi Tobias,

Am 31.08.20 um 23:59 schrieb Tobias Schramm:
> This commit enables ddr modes for eMMC storage on emmc2.
> The bcm2711 supports eMMC storage using ddr modes. The board
> layout of the Raspberry Pi 4 supports them, too.

i want to inform you that Ulf Hansson already applied my driver change
to mmc-next [1].

So this patch won't be necessary anymore.

Best regards

[1] - https://marc.info/?l=linux-mmc&m=159903747923131&w=2

>
> Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
> ---
>  arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> index 222d7825e1ab..1851efebe9c6 100644
> --- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> +++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> @@ -191,6 +191,7 @@ &emmc2 {
>  	vqmmc-supply = <&sd_io_1v8_reg>;
>  	vmmc-supply = <&sd_vcc_reg>;
>  	broken-cd;
> +	mmc-ddr-3_3v;
>  	status = "okay";
>  };
>