Zephyr开发体验

安装

编译和运行

参考west使用指南：

以qemu an521为例

west update
west build -p auto -b mps2_an521_ns -t run samples/hello_world

选项run表示编译后自动运行，参考west usage，输出

[INF] Beginning TF-M provisioning
[WRN] TFM_DUMMY_PROVISIONING is not suitable for production! This device is NOT SECURE
[Sec Thread] Secure image initializing!
Booting TF-M a8313be08
Creating an empty ITS flash layout.
Creating an empty PS flash layout.
[INF][Crypto] Provisioning entropy seed... complete.
*** Booting Zephyr OS build zephyr-v3.3.0-1195-g9a759025d912 ***
Hello World! mps2_an521_ns

显然，这里打开了默认的trusted firmware-M

使用Kconfig关闭编译选项

参考：Configuration System (Kconfig)

命令：

west build -p auto -b mps2_an521_ns samples/hello_world -t menuconfig

为了编译不含TF-M的版本，选择打开boards/arm/mps2_an521/Kconfig.defconfig看到：

config BOARD
    default "mps2_an521_ns" if TRUSTED_EXECUTION_NONSECURE
    default "mps2_an521_remote" if BOARD_MPS2_AN521_CPU1
    default "mps2_an521"

# By default, if we build for a Non-Secure version of the board,
# force building with TF-M as the Secure Execution Environment.
config BUILD_WITH_TFM
    default y if TRUSTED_EXECUTION_NONSECURE

运行

west build -p auto -b mps2_an521 samples/hello_world -t run

打开menuconfig看到

此时输出为：

*** Booting Zephyr OS build zephyr-v3.3.0-1195-g9a759025d912 ***
Hello World! mps2_an521

musca_s1开发板

板载资源可以在boards/arm/v2m_musca_s1/doc/index.rst找到，下载镜像，直接拷贝到存储区

west build -p auto -b v2m_musca_s1 samples/hello_world
cp build/zephyr/zephyr.hex /Volumes/MUSCA_S
minicom -D /dev/tty.usbmodem11302

output:
Musca-S1 Dual Firmware Version 1.9
*** Booting Zephyr OS build zephyr-v3.3.0-1195-g9a759025d912 ***
Hello World! musca_s1

应用开发

概述

应用既可以在zephyrproject/zephyr里面创建编译，也可以在外部建立prj文件夹，项目文件中应当包含：

<app>
├── CMakeLists.txt
├── app.overlay
├── prj.conf
└── src
    └── main.c

以samples/hello_world为例：

cmake文件，环境中一定要设置ZEPHYR_BASE
设备树文件
Kconfig配置文件，defconfig
C/C++源文件

调试

Zephyr运行qemu的命令是：

qemu-system-arm -cpu cortex-m33 \
                -machine mps2-an521 \
                -nographic -m 16 -vga none -net none \
                -pidfile qemu.pid \
                -chardev stdio,id=con,mux=on \
                -serial chardev:con \
                -mon chardev=con,mode=readline \
                -icount shift=6,align=off,sleep=off \
                -rtc clock=vm -chardev pty,id=hostS0 \
                -serial chardev:hostS0 \
                -kernel build/zephyr/zephyr.elf

加上-s，（-gdb tcp::1234的缩写）打开gdbserver，默认端口为：1234。也可以运行

west build -p auto -b mps2_an521 . -t debugserver_qemu

运行gdb命令：

arm-zephyr-eabi-gdb build/zephyr/zephyr.elf
(gdb) target remote localhost:1234
(gdb) dir ZEPHYR_BASE

使用工具连接调试硬件板

参考：Flash & Debug Host Tools

API

汇总：API Overview
使用说明：API Guildlines

内核系统开发

点灯

以musca-s1为例，在其设备树文件boards/arm/v2m_musca_s1/v2m_musca_s1.dts中：

    aliases {
        led0 = &red_led;
        led1 = &green_led;
    };

    leds {
        compatible = "gpio-leds";
        red_led: led_0 {
            gpios = <&gpio 2 0>;
            label = "User LED1";
        };
        green_led: led_1 {
            gpios = <&gpio 3 0>;
            label = "User LED2";
        };
    };

使用led0和led1，用两个线程进行闪烁，调用的是toggle接口，使用fifo和输出线程通信，打印log，配置如下：

CONFIG_PRINTK=y
CONFIG_HEAP_MEM_POOL_SIZE=256
CONFIG_ASSERT=y
CONFIG_GPIO=y

代码如下:

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/sys/printk.h>
#include <zephyr/sys/__assert.h>
#include <string.h>

/* 1000 msec = 1 sec */
#define SLEEP_TIME_MS 1000

/* size of stack area used by each thread */
#define STACKSIZE 1024

/* scheduling priority used by each thread */
#define PRIORITY 7

/* The devicetree node identifier for the "led0" alias. */
#define LED0_NODE DT_ALIAS(led0)
#define LED1_NODE DT_ALIAS(led1)

/*
 * A build error on this line means your board is unsupported.
 * See the sample documentation for information on how to fix this.
 */
static const struct gpio_dt_spec led0 = GPIO_DT_SPEC_GET(LED0_NODE, gpios);
static const struct gpio_dt_spec led1 = GPIO_DT_SPEC_GET(LED1_NODE, gpios);

struct printk_data_t
{
    void *fifo_reserved; /* 1st word reserved for use by fifo */
    uint32_t led;
    uint32_t cnt;
};

K_FIFO_DEFINE(printk_fifo);

void blink(const struct gpio_dt_spec *led, uint32_t sleep_ms, uint32_t id)
{
    int ret, cnt = 0;

    if (!gpio_is_ready_dt(led))
    {
        return;
    }

    ret = gpio_pin_configure_dt(led, GPIO_OUTPUT_ACTIVE);
    if (ret < 0)
    {
        return;
    }

    while (1)
    {

        ret = gpio_pin_toggle_dt(led);

        struct printk_data_t tx_data = {.led = id, .cnt = cnt};
        size_t size = sizeof(struct printk_data_t);

        char *mem_ptr = k_malloc(size);
        __ASSERT_NO_MSG(mem_ptr != 0);

        memcpy(mem_ptr, &tx_data, size);

        k_fifo_put(&printk_fifo, mem_ptr);

        k_msleep(sleep_ms);
        cnt++;
    }
}

void blink0(void)
{
    blink(&led0, SLEEP_TIME_MS, 0);
}

void blink1(void)
{
    blink(&led1, SLEEP_TIME_MS, 1);
}

void uart_out(void)
{
    while (1)
    {
        struct printk_data_t *rx_data = k_fifo_get(&printk_fifo,
                                                   K_FOREVER);
        printk("Toggled led%d; counter=%d\n",
               rx_data->led, rx_data->cnt);
        k_free(rx_data);
    }
}

K_THREAD_DEFINE(blink0_id, STACKSIZE, blink0, NULL, NULL, NULL,    PRIORITY, 0, 0);
K_THREAD_DEFINE(blink1_id, STACKSIZE, blink1, NULL, NULL, NULL,    PRIORITY, 0, SLEEP_TIME_MS);
K_THREAD_DEFINE(uart_out_id, STACKSIZE, uart_out, NULL, NULL, NULL, PRIORITY, 0, 0);