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From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: srinivas.kandagatla@linaro.org, linux-kernel@vger.kernel.org,
	Rob Herring <robh+dt@kernel.org>,
	Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk,
	catalin.marinas@arm.com, will@kernel.org,
	devicetree@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
	bcm-kernel-feedback-list@broadcom.com, tim.gover@raspberrypi.com,
	phil@raspberrypi.com
Subject: [PATCH v3 3/5] ARM: dts: bcm2711: Add reserved memory template to hold firmware configuration
Date: Tue, 12 Jan 2021 15:23:40 +0100	[thread overview]
Message-ID: <20210112142342.7290-4-nsaenzjulienne@suse.de> (raw)
In-Reply-To: <20210112142342.7290-1-nsaenzjulienne@suse.de>

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>

[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


  parent reply	other threads:[~2021-01-12 14:24 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-12 14:23 [PATCH v3 0/5] Expose RPi4's bootloader configuration Nicolas Saenz Julienne
2021-01-12 14:23 ` [PATCH v3 1/5] dt-bindings: nvmem: Add bindings for rmem driver Nicolas Saenz Julienne
2021-01-14 20:17   ` Rob Herring
2021-01-12 14:23 ` [PATCH v3 2/5] nvmem: Add driver to expose reserved memory as nvmem Nicolas Saenz Julienne
2021-01-12 14:23 ` Nicolas Saenz Julienne [this message]
2021-01-12 14:23 ` [PATCH v3 4/5] arm64: defconfig: Enable nvmem's rmem driver Nicolas Saenz Julienne
2021-01-12 14:23 ` [PATCH v3 5/5] ARM: multi_v7_defconfig: " Nicolas Saenz Julienne
2021-01-18 16:50 ` [PATCH v3 0/5] Expose RPi4's bootloader configuration Srinivas Kandagatla
2021-01-25 21:04 ` Nicolas Saenz Julienne

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