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@suse.de>
Tested-by: Tim Gover <tim.gover@raspberrypi.com>
Link: https://lore.kernel.org/r/e8ca9365-a1f2-1f9d-377c-13bf97883cce@linaro.org
[1] https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2711_bootloader_config.md
emmc2bus = &emmc2bus;
ethernet0 = &genet;
pcie0 = &pcie0;
+ blconfig = &blconfig;
};
leds {
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>;