samples: boards: milkv_duo: Add sample for mbox driver

This commit adds a mbox sample for the Milk-V Duo, a board equipped with
the SOPHGO CV1800B SoC.

The CV1800B is a multi-core SoC that consists of two C906 cores. The big
core, referred to as C906B, runs Linux, while the little core, referred to
as C906L, runs an RTOS.

This sample receives mailbox requests from the big core running the
official SDK's mailbox sample, prints the request body, and performs
example operations such as LED control.

Signed-off-by: honglin leng <a909204013@gmail.com>

samples/boards/milkv_duo/mbox/CMakeLists.txt

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(mbox)
+
+target_sources(app PRIVATE src/main.c)

samples/boards/milkv_duo/mbox/boards/milkv_duo.overlay

@@ -0,0 +1,8 @@
+/*
+ * Copyright (c) 2024 honglin leng <a909204013@gmail.com>
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&mbox {
+	status = "okay";
+};

samples/boards/milkv_duo/mbox/prj.conf

@@ -0,0 +1,4 @@
+CONFIG_PRINTK=y
+CONFIG_MBOX=y
+CONFIG_LOG=y
+CONFIG_GPIO=y

samples/boards/milkv_duo/mbox/src/main.c

@@ -0,0 +1,159 @@
+/*
+ * Copyright (c) 2024 honglin leng <a909204013@gmail.com>
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/mbox.h>
+#include <zephyr/drivers/gpio.h>
+#include <string.h>
+
+#define TX_ID (1)
+#define RX_ID (0)
+
+#define QUEUE_DEPTH 10
+
+struct k_msgq msgq;
+
+static const struct device *mbox = DEVICE_DT_GET(DT_NODELABEL(mbox));
+static const struct gpio_dt_spec led = GPIO_DT_SPEC_GET(DT_ALIAS(led0), gpios);
+
+struct valid_t {
+	unsigned char linux_valid;
+	unsigned char rtos_valid;
+};
+typedef union resv_t {
+	struct valid_t valid;
+	unsigned short mstime;
+} resv_t;
+
+typedef struct cmdqu_t cmdqu_t;
+/* cmdqu size should be 8 bytes because of mailbox buffer size */
+struct cmdqu_t {
+	unsigned char ip_id;
+	unsigned char cmd_id: 7;
+	unsigned char block: 1;
+	union resv_t resv;
+	unsigned int param_ptr;
+} __packed;
+
+enum SYS_CMD_ID {
+	CMD_TEST_A = 0x10,
+	CMD_TEST_B,
+	CMD_TEST_C,
+	CMD_DUO_LED,
+	SYS_CMD_INFO_LIMIT,
+};
+
+enum DUO_LED_STATUS {
+	DUO_LED_ON = 0x02,
+	DUO_LED_OFF,
+	DUO_LED_DONE,
+};
+
+cmdqu_t main_cmdq[QUEUE_DEPTH];
+
+static void callback(const struct device *dev, uint32_t channel, void *user_data,
+		     struct mbox_msg *data)
+{
+	cmdqu_t cmdq;
+
+	memcpy(&cmdq, data->data, sizeof(cmdqu_t));
+	k_msgq_put(&msgq, &cmdq, K_NO_WAIT);
+}
+
+int main(void)
+{
+	struct mbox_channel tx_channel;
+	struct mbox_channel rx_channel;
+	struct mbox_msg msg;
+	int ret;
+	cmdqu_t cmdq;
+
+	k_msgq_init(&msgq, (char *)main_cmdq, sizeof(cmdqu_t), QUEUE_DEPTH);
+
+	mbox_init_channel(&tx_channel, mbox, TX_ID);
+	mbox_init_channel(&rx_channel, mbox, RX_ID);
+
+	if (mbox_register_callback(&rx_channel, callback, NULL)) {
+		printk("mbox_register_callback() error\n");
+		return 0;
+	}
+
+	if (mbox_set_enabled(&rx_channel, 1)) {
+		printk("mbox_set_enable() error\n");
+		return 0;
+	}
+
+	if (!gpio_is_ready_dt(&led)) {
+		return 0;
+	}
+
+	ret = gpio_pin_configure_dt(&led, GPIO_OUTPUT_ACTIVE);
+	if (ret < 0) {
+		return 0;
+	}
+
+	while (1) {
+		ret = k_msgq_get(&msgq, &cmdq, K_FOREVER);
+		if (ret != 0) {
+			return 0;
+		}
+
+		printk("cmdq->ip_id =%d\n", cmdq.ip_id);
+		printk("cmdq->cmd_id =%d\n", cmdq.cmd_id);
+		printk("cmdq->param_ptr =%x\n", cmdq.param_ptr);
+		printk("Ping (on channel %d)\n", tx_channel.id);
+
+		switch (cmdq.cmd_id) {
+		case CMD_TEST_A:
+			/* send to C906B */
+			cmdq.cmd_id = CMD_TEST_A;
+			cmdq.param_ptr = 0x12345678;
+			cmdq.resv.valid.rtos_valid = 1;
+			cmdq.resv.valid.linux_valid = 0;
+			printk("recv cmd(%d) from C906B...send [0x%x] to C906B\n", cmdq.cmd_id,
+			       cmdq.param_ptr);
+			break;
+		case CMD_TEST_B:
+			printk("nothing to do...\n");
+			continue;
+		case CMD_TEST_C:
+			cmdq.cmd_id = CMD_TEST_C;
+			cmdq.param_ptr = 0x55aa;
+			cmdq.resv.valid.rtos_valid = 1;
+			cmdq.resv.valid.linux_valid = 0;
+			printk("recv cmd(%d) from C906B...send [0x%x] to C906B\n", cmdq.cmd_id,
+			       cmdq.param_ptr);
+			break;
+		case CMD_DUO_LED:
+			cmdq.cmd_id = CMD_DUO_LED;
+			printk("recv cmd(%d) from C906B, param_ptr [0x%x]\n", cmdq.cmd_id,
+			       cmdq.param_ptr);
+			if (cmdq.param_ptr == DUO_LED_ON) {
+				gpio_pin_set_dt(&led, 1);
+			} else {
+				gpio_pin_set_dt(&led, 0);
+			}
+			cmdq.param_ptr = DUO_LED_DONE;
+			cmdq.resv.valid.rtos_valid = 1;
+			cmdq.resv.valid.linux_valid = 0;
+			printk("recv cmd(%d) from C906B...send [0x%x] to C906B\n", cmdq.cmd_id,
+			       cmdq.param_ptr);
+			break;
+		default:
+			break;
+		}
+
+		msg.data = &cmdq;
+		msg.size = sizeof(cmdqu_t);
+		if (mbox_send(&tx_channel, &msg) < 0) {
+			printk("mbox_send() error\n");
+			return 0;
+		}
+	}
+
+	return 0;
+}