MAX32 RV32 (RISC-V) secondary core support

boards/adi/apard32690/apard32690_max32690_m4.dts

@@ -6,7 +6,7 @@
 
 /dts-v1/;
 
-#include <adi/max32/max32690.dtsi>
+#include <adi/max32/max32690-m4.dtsi>
 #include <adi/max32/max32690-pinctrl.dtsi>
 #include <zephyr/dt-bindings/gpio/adi-max32-gpio.h>
 #include <zephyr/dt-bindings/gpio/arduino-header-r3.h>

boards/adi/max32655evkit/Kconfig.max32655evkit

@@ -5,3 +5,4 @@
 
 config BOARD_MAX32655EVKIT
 	select SOC_MAX32655_M4 if BOARD_MAX32655EVKIT_MAX32655_M4
+	select SOC_MAX32655_RV32 if BOARD_MAX32655EVKIT_MAX32655_RV32

boards/adi/max32655evkit/doc/index.rst

@@ -154,10 +154,73 @@ Debugging
 Please refer to the `Flashing`_ section and run the ``west debug`` command
 instead of ``west flash``.
 
+Dual Core Support
+*****************
+
+An experimental board configuration for the secondary RISC-V core can be found
+in
+:zephyr_file:`boards/adi/max32655evkit/max32655evkit_max32655_rv32_defconfig`.
+
+It can boot Zephyr and print "hello world" to a RAM console, but it currently
+has significant limitations:
+
+- **Kernel timer**: The zero-riscy core doesn't implement a machine timer and we
+  have not yet implemented a Zephyr driver for a system-level timer peripheral
+  on this SoC, therefore kernel functions that take a :c:type:`k_timeout_t`
+  argument, such as :c:func:`k_sleep` are not expected to work.
+
+- **Interrupts**: The zero-riscy core only allows enabling/disabling interrupts
+  globally and assumes there is an interrupt controller outside of the core. We
+  have not yet implemented support for a system-level interrupt controller,
+  therefore kernel interrupt services are not expected to work.
+
+- **Peripheral drivers**: Without interrupts, the existing UART, GPIO, and
+  other peripheral drivers won't work.
+
+The primary Arm core uses Kconfig options,
+:kconfig:option:`CONFIG_MAX32_SECONDARY_RV32` and
+:kconfig:option:`CONFIG_MAX32_SECONDARY_RV32_BOOT_ADDRESS`, to enable and
+configure the boot address for the secondary RISC-V core. The devicetree chosen
+node, ``zephyr,code-rv32-partition``, specifies the default value for the boot
+address.
+
+:zephyr:code-sample:`sysbuild_hello_world` supports building the Arm and RISC-V
+images:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/sysbuild/hello_world
+   :board: max32655evkit/max32655/m4
+   :west-args: -T sample.sysbuild.hello_world.max32655evkit_m4_rv32
+   :goals: build
+   :compact:
+
+The build system hasn't yet been instrumented to merge the two images into one
+combined image, so you can use :zephyr_file:`scripts/build/mergehex.py` to
+merge them:
+
+.. code-block:: console
+
+   $ python scripts/build/mergehex.py -o build/merged.hex \
+        build/hello_world/zephyr/zephyr.hex build/remote/zephyr/zephyr.hex
+
+Likewise, west runners aren't aware of combined image, so you can use JLink to
+program it to flash:
+
+.. code-block:: console
+
+   $ JLinkExe -device MAX32655 -if SWD -speed 4000 -autoconnect 1
+
+   J-Link>loadfile build/merged.hex
+
 References
 **********
 
 - `MAX32655EVKIT web page`_
 
+- `zero-riscy user manual`_
+
 .. _MAX32655EVKIT web page:
    https://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/max32655evkit.html#eb-overview
+
+.. _zero-riscy user manual:
+   https://pulp-platform.org/docs/user_manual.pdf

boards/adi/max32655evkit/max32655evkit.dtsi

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2023-2024 Analog Devices, Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <adi/max32/max32655-pinctrl.dtsi>
+#include <zephyr/dt-bindings/gpio/adi-max32-gpio.h>
+#include <zephyr/dt-bindings/input/input-event-codes.h>
+
+/ {
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		/*
+		 * Concatenate SRAM0(32KB), SRAM1(32KB) and SRAM2(48KB) for the M4
+		 */
+		m4_sram: memory@20000000 {
+			compatible = "mmio-sram";
+			reg = <0x20000000 DT_SIZE_K(112)>;
+		};
+
+		/*
+		 * Use SRAM3(16KB) for the RV32
+		 */
+		rv32_sram: memory@2001c000 {
+			compatible = "mmio-sram";
+			reg = <0x2001c000 DT_SIZE_K(16)>;
+		};
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		led1: led_1 {
+			gpios = <&gpio0 24 GPIO_ACTIVE_LOW>;
+			label = "Red LED";
+		};
+
+		led2: led_2 {
+			gpios = <&gpio0 25 GPIO_ACTIVE_LOW>;
+			label = "Blue LED";
+		};
+	};
+
+	buttons {
+		compatible = "gpio-keys";
+
+		pb1: pb1 {
+			gpios = <&gpio0 18 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+			label = "SW2";
+			zephyr,code = <INPUT_KEY_0>;
+		};
+
+		pb2: pb2 {
+			gpios = <&gpio0 19 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+			label = "SW3";
+			zephyr,code = <INPUT_KEY_1>;
+		};
+
+		pb_wakeup: pb_wakeup {
+			gpios = <&gpio3 1
+				 (GPIO_PULL_UP | GPIO_ACTIVE_LOW | MAX32_GPIO_VSEL_VDDIOH)>;
+			label = "Wakeup";
+			zephyr,code = <INPUT_KEY_WAKEUP>;
+		};
+	};
+
+	/* These aliases are provided for compatibility with samples */
+	aliases {
+		led0 = &led1;
+		led1 = &led2;
+		sw0 = &pb1;
+		sw1 = &pb2;
+		watchdog0 = &wdt0;
+	};
+};
+
+&uart0 {
+	pinctrl-0 = <&uart0a_tx_p0_1 &uart0a_rx_p0_0>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	data-bits = <8>;
+	parity = "none";
+};
+
+&flash0 {
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		m4_partition: partition@10000000 {
+			label = "image-m4";
+			reg = <0x10000000 DT_SIZE_K(256)>;
+		};
+
+		rv32_partition: partition@10040000 {
+			label = "image-rv32";
+			reg = <0x10040000 DT_SIZE_K(256)>;
+		};
+	};
+};

boards/adi/max32655evkit/max32655evkit_max32655_m4.dts

@@ -6,10 +6,8 @@
 
 /dts-v1/;
 
-#include <adi/max32/max32655.dtsi>
-#include <adi/max32/max32655-pinctrl.dtsi>
-#include <zephyr/dt-bindings/gpio/adi-max32-gpio.h>
-#include <zephyr/dt-bindings/input/input-event-codes.h>
+#include <adi/max32/max32655-m4.dtsi>
+#include "max32655evkit.dtsi"
 
 / {
 	model = "Analog Devices MAX32655EVKIT";
@@ -18,64 +16,48 @@
 	chosen {
 		zephyr,console = &uart0;
 		zephyr,shell-uart = &uart0;
-		zephyr,sram = &sram2;
-		zephyr,flash = &flash0;
+		zephyr,sram = &m4_sram;
+		zephyr,flash = &m4_partition;
+		zephyr,code-rv32-partition = &rv32_partition;
 	};
 
-	leds {
-		compatible = "gpio-leds";
+	aliases {
+		spi-flash0 = &spi0_cs0_flash;
+	};
+};
 
-		led1: led_1 {
-			gpios = <&gpio0 24 GPIO_ACTIVE_LOW>;
-			label = "Red LED";
-		};
+&cpu1 {
+	pinctrl-0 = <&rv_tck_p1_0 &rv_tms_p1_1 &rv_tdi_p1_2 &rv_tdo_p1_3>;
+	pinctrl-names = "default";
+};
 
-		led2: led_2 {
-			gpios = <&gpio0 25 GPIO_ACTIVE_LOW>;
-			label = "Blue LED";
-		};
-	};
+&led1 {
+	status = "okay";
+};
 
-	buttons {
-		compatible = "gpio-keys";
-
-		pb1: pb1 {
-			gpios = <&gpio0 18 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
-			label = "SW2";
-			zephyr,code = <INPUT_KEY_0>;
-		};
-
-		pb2: pb2 {
-			gpios = <&gpio0 19 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
-			label = "SW3";
-			zephyr,code = <INPUT_KEY_1>;
-		};
-
-		pb_wakeup: pb_wakeup {
-			gpios = <&gpio3 1
-				 (GPIO_PULL_UP | GPIO_ACTIVE_LOW | MAX32_GPIO_VSEL_VDDIOH)>;
-			label = "Wakeup";
-			zephyr,code = <INPUT_KEY_WAKEUP>;
-		};
-	};
+&led2 {
+	status = "okay";
+};
 
-	/* These aliases are provided for compatibility with samples */
-	aliases {
-		led0 = &led1;
-		led1 = &led2;
-		sw0 = &pb1;
-		sw1 = &pb2;
-		watchdog0 = &wdt0;
-	};
+&pb1 {
+	status = "okay";
+};
+
+&pb2 {
+	status = "okay";
+};
+
+&pb_wakeup {
+	status = "okay";
 };
 
 &uart0 {
 	pinctrl-0 = <&uart0a_tx_p0_1 &uart0a_rx_p0_0>;
+	status = "okay";
 	pinctrl-names = "default";
 	current-speed = <115200>;
 	data-bits = <8>;
 	parity = "none";
-	status = "okay";
 };
 
 &clk_ipo {
@@ -123,12 +105,6 @@
 	status = "okay";
 };
 
-&spi0 {
-	status = "okay";
-	pinctrl-0 = <&spi0_mosi_p0_5 &spi0_miso_p0_6 &spi0_sck_p0_7 &spi0_ss0_p0_4>;
-	pinctrl-names = "default";
-};
-
 &w1 {
 	pinctrl-0 = <&owm_io_p0_6 &owm_pe_p0_7>;
 	pinctrl-names = "default";
@@ -151,10 +127,10 @@
 };
 
 &spi0 {
-	status = "okay";
 	pinctrl-0 = <&spi0_mosi_p0_5 &spi0_miso_p0_6 &spi0_sck_p0_7>;
 	pinctrl-names = "default";
 	cs-gpios = <&gpio0 4 (GPIO_ACTIVE_LOW | MAX32_GPIO_VSEL_VDDIOH)>;
+	status = "okay";
 
 	spi0_cs0_flash: w25q128@0 {
 		compatible = "jedec,spi-nor";

boards/adi/max32655evkit/max32655evkit_max32655_m4.yaml

@@ -22,4 +22,4 @@ supported:
   - w1
   - flash
 ram: 48
-flash: 512
+flash: 256

boards/adi/max32655evkit/max32655evkit_max32655_rv32.dts

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2023-2024 Analog Devices, Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+
+#include <adi/max32/max32655-rv32.dtsi>
+#include "max32655evkit.dtsi"
+
+/ {
+	model = "Analog Devices MAX32655EVKIT";
+	compatible = "adi,max32655evkit";
+
+	chosen {
+		zephyr,console = &uart3;
+		zephyr,shell-uart = &uart3;
+		zephyr,sram = &rv32_sram;
+		zephyr,flash = &rv32_partition;
+	};
+};
+
+&rv32_sys_timer {
+	status = "okay";
+};
+
+&clk_iso {
+	status = "okay";
+};
+
+/*
+ * ERTCO is required for counter RTC
+ */
+&clk_ertco {
+	status = "okay";
+};
+
+&gpio0 {
+	status = "okay";
+};
+
+&gpio1 {
+	status = "okay";
+};
+
+&gpio2 {
+	status = "okay";
+};
+
+&gpio3 {
+	status = "okay";
+};
+
+&uart3 {
+	pinctrl-0 = <&lpuartb_rx_p2_6 &lpuartb_tx_p2_7>;
+	status = "okay";
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	data-bits = <8>;
+	parity = "none";
+};