Re: [PATCH 3/6] ARM: dts: bcm2711: Add reserved memory template to hold firmware configuration
From: Rob Herring
Date: Tue Dec 15 2020 - 15:28:20 EST
On Tue, Dec 15, 2020 at 9:56 AM Nicolas Saenz Julienne
<nsaenzjulienne@xxxxxxx> wrote:
>
> RPi4's co-processor will copy the board's bootloader configuration into
> memory for the OS to consume. Introduce a reserved-memory area template
> for the co-processor to edit before booting the system so as for Linux
> not to overwrite that memory.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
> ---
> arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> index 403bacf986eb..c58e58e8ce39 100644
> --- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> +++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> @@ -25,6 +25,7 @@ aliases {
> emmc2bus = &emmc2bus;
> ethernet0 = &genet;
> pcie0 = &pcie0;
> + eeprom = &eeprom;
I don't see the need for this...
> };
>
> leds {
> @@ -218,6 +219,19 @@ &pwm1 {
> status = "okay";
> };
>
> +&rmem {
> + /*
> + * RPi4's co-processor will copy the board's bootloader configuration
> + * into memory for the OS to consume. It'll also update this node with
> + * its placement information.
> + */
> + eeprom: eeprom@0 {
But it's not an eeprom. It's just memory with some format to the contents.
> + reg = <0x0 0x0 0x0>;
> + no-map;
> + status = "disabled";
> + };
> +};
> +
> /* SDHCI is used to control the SDIO for wireless */
> &sdhci {
> #address-cells = <1>;
> --
> 2.29.2
>