RPi4's co-processor will copy the board's bootloader[1] configuration into memory for the OS to consume. Specifically, for the bootloader configuration and upgrade user-space routines to query it through nvmem's sysfs interface. 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 and to expose it as an nvmem device. Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx> Tested-by: Tim Gover <tim.gover@xxxxxxxxxxxxxxx> [1] https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2711_bootloader_config.md --- Changes since v1: - Introduce compatible string - Change alias name to something more explicit arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 17 +++++++++++++++++ 1 file changed, 17 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..3b4ab947492a 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; + blconfig = &blconfig; }; leds { @@ -218,6 +219,22 @@ &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. + */ + blconfig: nvram@0 { + compatible = "raspberrypi,bootloader-config", "nvmem-rmem"; + #address-cells = <1>; + #size-cells = <1>; + reg = <0x0 0x0 0x0>; + no-map; + status = "disabled"; + }; +}; + /* SDHCI is used to control the SDIO for wireless */ &sdhci { #address-cells = <1>; -- 2.29.2
