On 3/3/20 4:08 AM, Nicolas Saenz Julienne wrote:
> Depending on bcm2711's revision its emmc2 controller might have
> different DMA constraints. Raspberry Pi 4's firmware will take care of
> updating those, but only if a certain alias is found in the device tree.
> So, move emmc2 into its own bus, so as not to pollute other devices with
> dma-ranges changes and create the emmc2bus alias.
>
> Based in Phil ELwell's downstream implementation.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
Nit: the subject should be ARM: dts: bcm2711. Some more comments below.
> ---
> arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 1 +
> arch/arm/boot/dts/bcm2711.dtsi | 19 ++++++++++++++-----
> 2 files changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> index 1d4b589fe233..e26ea9006378 100644
> --- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> +++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> @@ -20,6 +20,7 @@ memory@0 {
> };
>
> aliases {
> + emmc2bus = &emmc2bus;
> ethernet0 = &genet;
> pcie0 = &pcie0;
> };
> diff --git a/arch/arm/boot/dts/bcm2711.dtsi b/arch/arm/boot/dts/bcm2711.dtsi
> index d1e684d0acfd..61ea8b44c51e 100644
> --- a/arch/arm/boot/dts/bcm2711.dtsi
> +++ b/arch/arm/boot/dts/bcm2711.dtsi
> @@ -241,17 +241,26 @@ pwm1: pwm@7e20c800 {
> status = "disabled";
> };
>
> + hvs@7e400000 {
> + interrupts = <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>;
> + };
> + };
> +
> + emmc2bus: emmc2bus {
> + compatible = "simple-bus";
> + #address-cells = <2>;
> + #size-cells = <1>;
> +
> + ranges = <0x0 0x7e000000 0x0 0xfe000000 0x01800000>;
> + dma-ranges = <0x0 0xc0000000 0x0 0x00000000 0x40000000>;
This deserves a comment for two reasons:
- explaining which of these properties is getting patched by the
firmware (and it would be really nice if we had a concept of annotation
attributes for Device Tree such that you could express something like:
dma-ranges = <> __patchable;
- explaining why this is not collapsed in the soc bus node, because the
dma-ranges constraint can be different based on the Pi4 revision
With that fixed, this looks good to me!
> +
> emmc2: emmc2@7e340000 {
> compatible = "brcm,bcm2711-emmc2";
> - reg = <0x7e340000 0x100>;
> + reg = <0x0 0x7e340000 0x100>;
> interrupts = <GIC_SPI 126 IRQ_TYPE_LEVEL_HIGH>;
> clocks = <&clocks BCM2711_CLOCK_EMMC2>;
> status = "disabled";
> };
> -
> - hvs@7e400000 {
> - interrupts = <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>;
> - };
> };
>
> arm-pmu {
>
--
Florian
