Allow bare minimum platform device core and driver to be easily tested

Provide a forked `defconfig` and devicetree, so the platform device core and driver can be easily tested on QEMU, or a Raspberri Pi Zero. Although called "bcm2835-rng-rust", this is not a functional hwrng driver, just a bare minimum platform_device. All it will do is log a message to dmesg: [ ] rust_kernel: Rust platform_device probed and show up in sysfs: /sys/bus/platform/driver/bcm2835-rng-rust/ (the driver) /sys/bus/platform/devices/bcm2835-rng-rust/ (the device) How to run on QEMU ================== Download a Raspbian image. I used `2021-03-04-raspios-buster-armhf-lite.img`. It will consist of two partitions. Discover their offsets using: ```sh $ fdisk -l 2021-03-04-raspios-buster-armhf-lite.img Device Boot Start End Sectors Size Id Type 2021-03-04-raspios-buster-armhf-lite.img1 8192 532479 524288 256M c W95 FAT32 (LBA) 2021-03-04-raspios-buster-armhf-lite.img2 532480 3645439 3112960 1.5G 83 Linux ``` Mount the second partition on your PC: (note how the offset is multiplied by 512) ```sh $ mount -o loop,offset=$((512*532480)) 2021-03-04-raspios-buster-armhf-lite.img /mnt Comment out everything in /etc/ld.so.preload - otherwise the Raspbian rootfs cannot support a mainline kernel: $ vi /etc/ld.so.preload # comment everything out $ umount /mnt ``` Build the kernel for arm 32-bit: ```sh $ make bcm2835_rust_defconfig # defconfig forked so `bcm2835-rng-rust` binds to our driver $ make zImage dtbs modules ``` Start QEMU: ```sh # to boot mainline, make sure that /etc/ld.so.preload is commented out # in the Raspbian image. qemu-system-arm \ -M raspi2 \ -append "rw earlyprintk loglevel=8 console=ttyAMA0,115200 dwc_otg.lpm_enable=0 root=/dev/mmcblk0p2 rootwait" \ -cpu arm1176 \ -dtb bcm2836-rpi-2-b-rust.dts \ -hda ./2021-03-04-raspios-buster-armhf-lite.img \ -kernel zImage \ -m 1G \ -smp 4 \ -nographic \ ; How to run on a Raspberry Pi Zero(W) ==================================== Follow the instructions for QEMU above. Deploy the Raspbian image to SD card. Copy zImage and bcm2835-rpi-zero-w-rust.dtb to Raspbian's first (boot) partition: ``` zImage -> boot partition: kernel.img bcm2835-rpi-zero-w-rust.dtb -> boot partition: bcm2708-rpi-0-w.dtb ``` If you'd like wifi to keep working, also copy the kernel modules you built to Raspbian's second partition: ```sh $ make modules_install INSTALL_MOD_PATH=<somewhere> $ cp -rfa <somewhere> <Raspbian Partition> # should end up in /lib/modules/5.12.0-rc4+/ ``` Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
aiChaoSONG · May 18, 2021 · 9551aa5 · 9551aa5
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diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
@@ -84,13 +84,15 @@ dtb-$(CONFIG_ARCH_BCM2835) += \
 	bcm2835-rpi-a-plus.dtb \
 	bcm2835-rpi-cm1-io1.dtb \
 	bcm2836-rpi-2-b.dtb \
+	bcm2836-rpi-2-b-rust.dtb \
 	bcm2837-rpi-3-a-plus.dtb \
 	bcm2837-rpi-3-b.dtb \
 	bcm2837-rpi-3-b-plus.dtb \
 	bcm2837-rpi-cm3-io3.dtb \
 	bcm2711-rpi-4-b.dtb \
 	bcm2835-rpi-zero.dtb \
-	bcm2835-rpi-zero-w.dtb
+	bcm2835-rpi-zero-w.dtb \
+	bcm2835-rpi-zero-w-rust.dtb
 dtb-$(CONFIG_ARCH_BCM_5301X) += \
 	bcm4708-asus-rt-ac56u.dtb \
 	bcm4708-asus-rt-ac68u.dtb \

diff --git a/arch/arm/boot/dts/bcm2835-rpi-zero-w-rust.dts b/arch/arm/boot/dts/bcm2835-rpi-zero-w-rust.dts
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017 Stefan Wahren <stefan.wahren@i2se.com>
+ */
+
+/dts-v1/;
+#include "bcm2835.dtsi"
+#include "bcm2835-rpi.dtsi"
+#include "bcm283x-rpi-usb-otg.dtsi"
+
+/ {
+	compatible = "raspberrypi,model-zero-w", "brcm,bcm2835";
+	model = "Raspberry Pi Zero W";
+
+	bcm2835-rng-rust {
+		compatible = "brcm,bcm2835-rng";
+		status = "okay";
+	};
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0 0x20000000>;
+	};
+
+	chosen {
+		/* 8250 auxiliary UART instead of pl011 */
+		stdout-path = "serial1:115200n8";
+	};
+
+	leds {
+		act {
+			gpios = <&gpio 47 GPIO_ACTIVE_LOW>;
+		};
+	};
+
+	wifi_pwrseq: wifi-pwrseq {
+		compatible = "mmc-pwrseq-simple";
+		reset-gpios = <&gpio 41 GPIO_ACTIVE_LOW>;
+	};
+};
+
+&gpio {
+	/*
+	 * This is based on the official GPU firmware DT blob.
+	 *
+	 * Legend:
+	 * "NC" = not connected (no rail from the SoC)
+	 * "FOO" = GPIO line named "FOO" on the schematic
+	 * "FOO_N" = GPIO line named "FOO" on schematic, active low
+	 */
+	gpio-line-names = "ID_SDA",
+			  "ID_SCL",
+			  "SDA1",
+			  "SCL1",
+			  "GPIO_GCLK",
+			  "GPIO5",
+			  "GPIO6",
+			  "SPI_CE1_N",
+			  "SPI_CE0_N",
+			  "SPI_MISO",
+			  "SPI_MOSI",
+			  "SPI_SCLK",
+			  "GPIO12",
+			  "GPIO13",
+			  /* Serial port */
+			  "TXD0",
+			  "RXD0",
+			  "GPIO16",
+			  "GPIO17",
+			  "GPIO18",
+			  "GPIO19",
+			  "GPIO20",
+			  "GPIO21",
+			  "GPIO22",
+			  "GPIO23",
+			  "GPIO24",
+			  "GPIO25",
+			  "GPIO26",
+			  "GPIO27",
+			  "SDA0",
+			  "SCL0",
+			  "NC", /* GPIO30 */
+			  "NC", /* GPIO31 */
+			  "NC", /* GPIO32 */
+			  "NC", /* GPIO33 */
+			  "NC", /* GPIO34 */
+			  "NC", /* GPIO35 */
+			  "NC", /* GPIO36 */
+			  "NC", /* GPIO37 */
+			  "NC", /* GPIO38 */
+			  "NC", /* GPIO39 */
+			  "CAM_GPIO1", /* GPIO40 */
+			  "WL_ON", /* GPIO41 */
+			  "NC", /* GPIO42 */
+			  "WIFI_CLK", /* GPIO43 */
+			  "CAM_GPIO0", /* GPIO44 */
+			  "BT_ON", /* GPIO45 */
+			  "HDMI_HPD_N",
+			  "STATUS_LED_N",
+			  /* Used by SD Card */
+			  "SD_CLK_R",
+			  "SD_CMD_R",
+			  "SD_DATA0_R",
+			  "SD_DATA1_R",
+			  "SD_DATA2_R",
+			  "SD_DATA3_R";
+
+	pinctrl-0 = <&gpioout &alt0>;
+};
+
+&hdmi {
+	hpd-gpios = <&gpio 46 GPIO_ACTIVE_LOW>;
+	power-domains = <&power RPI_POWER_DOMAIN_HDMI>;
+	status = "okay";
+};
+
+&sdhci {
+	#address-cells = <1>;
+	#size-cells = <0>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&emmc_gpio34 &gpclk2_gpio43>;
+	bus-width = <4>;
+	mmc-pwrseq = <&wifi_pwrseq>;
+	non-removable;
+	status = "okay";
+
+	brcmf: wifi@1 {
+		reg = <1>;
+		compatible = "brcm,bcm4329-fmac";
+	};
+};
+
+&sdhost {
+	pinctrl-names = "default";
+	pinctrl-0 = <&sdhost_gpio48>;
+	bus-width = <4>;
+	status = "okay";
+};
+
+&uart0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart0_gpio32 &uart0_ctsrts_gpio30>;
+	status = "okay";
+
+	bluetooth {
+		compatible = "brcm,bcm43438-bt";
+		max-speed = <2000000>;
+		shutdown-gpios = <&gpio 45 GPIO_ACTIVE_HIGH>;
+	};
+};
+
+&uart1 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart1_gpio14>;
+	status = "okay";
+};
diff --git a/arch/arm/boot/dts/bcm2836-rpi-2-b-rust.dts b/arch/arm/boot/dts/bcm2836-rpi-2-b-rust.dts
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0
+/dts-v1/;
+#include "bcm2836.dtsi"
+#include "bcm2836-rpi.dtsi"
+#include "bcm283x-rpi-smsc9514.dtsi"
+#include "bcm283x-rpi-usb-host.dtsi"
+
+/ {
+	compatible = "raspberrypi,2-model-b", "brcm,bcm2836";
+	model = "Raspberry Pi 2 Model B";
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0 0x40000000>;
+	};
+
+	bcm2835-rng-rust {
+		compatible = "brcm,bcm2835-rng";
+		status = "okay";
+	};
+
+	leds {
+		act {
+			gpios = <&gpio 47 GPIO_ACTIVE_HIGH>;
+		};
+
+		pwr {
+			label = "PWR";
+			gpios = <&gpio 35 GPIO_ACTIVE_HIGH>;
+			default-state = "keep";
+			linux,default-trigger = "default-on";
+		};
+	};
+};
+
+&gpio {
+	/*
+	 * Taken from rpi_SCH_2b_1p2_reduced.pdf and
+	 * the official GPU firmware DT blob.
+	 *
+	 * Legend:
+	 * "NC" = not connected (no rail from the SoC)
+	 * "FOO" = GPIO line named "FOO" on the schematic
+	 * "FOO_N" = GPIO line named "FOO" on schematic, active low
+	 */
+	gpio-line-names = "ID_SDA",
+			  "ID_SCL",
+			  "SDA1",
+			  "SCL1",
+			  "GPIO_GCLK",
+			  "GPIO5",
+			  "GPIO6",
+			  "SPI_CE1_N",
+			  "SPI_CE0_N",
+			  "SPI_MISO",
+			  "SPI_MOSI",
+			  "SPI_SCLK",
+			  "GPIO12",
+			  "GPIO13",
+			  /* Serial port */
+			  "TXD0",
+			  "RXD0",
+			  "GPIO16",
+			  "GPIO17",
+			  "GPIO18",
+			  "GPIO19",
+			  "GPIO20",
+			  "GPIO21",
+			  "GPIO22",
+			  "GPIO23",
+			  "GPIO24",
+			  "GPIO25",
+			  "GPIO26",
+			  "GPIO27",
+			  "SDA0",
+			  "SCL0",
+			  "", /* GPIO30 */
+			  "LAN_RUN",
+			  "CAM_GPIO1",
+			  "", /* GPIO33 */
+			  "", /* GPIO34 */
+			  "PWR_LOW_N",
+			  "", /* GPIO36 */
+			  "", /* GPIO37 */
+			  "USB_LIMIT",
+			  "", /* GPIO39 */
+			  "PWM0_OUT",
+			  "CAM_GPIO0",
+			  "SMPS_SCL",
+			  "SMPS_SDA",
+			  "ETHCLK",
+			  "PWM1_OUT",
+			  "HDMI_HPD_N",
+			  "STATUS_LED",
+			  /* Used by SD Card */
+			  "SD_CLK_R",
+			  "SD_CMD_R",
+			  "SD_DATA0_R",
+			  "SD_DATA1_R",
+			  "SD_DATA2_R",
+			  "SD_DATA3_R";
+
+	pinctrl-0 = <&gpioout &alt0 &i2s_alt0>;
+
+	/* I2S interface */
+	i2s_alt0: i2s_alt0 {
+		brcm,pins = <18 19 20 21>;
+		brcm,function = <BCM2835_FSEL_ALT0>;
+	};
+};
+
+&hdmi {
+	hpd-gpios = <&gpio 46 GPIO_ACTIVE_LOW>;
+	power-domains = <&power RPI_POWER_DOMAIN_HDMI>;
+	status = "okay";
+};
+
+&pwm {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pwm0_gpio40 &pwm1_gpio45>;
+	status = "okay";
+};
+
+&sdhost {
+	pinctrl-names = "default";
+	pinctrl-0 = <&sdhost_gpio48>;
+	bus-width = <4>;
+	status = "okay";
+};
+
+&uart0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart0_gpio14>;
+	status = "okay";
+};