Small System STM32MP1 SoC Porting Case

This document describes how to port small development boards with screens based on the BearPi-HM Micro development board of the STM32MP157 SoC from STMicroelectronics, so as to adapt components such as ace_engine_lite, arkui_ui_lite, aafwk_lite, appexecfwk_lite, and HDF to the OpenHarmony LiteOS-A kernel. The porting architecture uses the solution where Board and SoC are separated.

Compilation and Building

Directory Planning

This solution designs the directory structure using the board and SoC decoupling idea, and plans the SoC adaptation directory as follows:

device
├── board                               --- Board vendor directory
│   └── bearpi                          --- Board vendor: BearPi
│       └── bearpi_hm_micro             --- Board name: bearpi_hm_micro
└── soc                                 --- SoC vendor directory
    └── common                          --- Directory storing common HDF drivers.
    └── st                              --- SoC vendor: STMicroelectronics
        └── stm32mp1xx                  --- SoC series: stm32mp1xx

The planned product demo directory is as follows:

vendor
└── bearpi                              --- Vendor of the product demo, which is BearPi here
    └── bearpi_hm_micro                 --- Product name: bearpi_hm_micro development board

Precompilation Adaptation

Before porting, you need to perform precompilation adaptation.

The precompilation adaptation process mainly uses the hb set command to set environment variables such as the project root directory, board directory, product directory, and board vendor name, to make preparations for compilation.

The procedure is as follows:

Add the config.json file to the vendor/bearpi/bearpi_hm_micro directory to describe board and kernel information used by the product demo. The sample code is as follows:

{
  "product_name": "bearpi_hm_micro",    --- Product name displayed when the **hb set** command is used.
  "version": "3.0",                     --- Version of the system, which can be 1.0, 2.0, or 3.0.
  "type": "small",                      --- System type, which can be mini, small, or standard.
  "ohos_version": "OpenHarmony 3.0",    --- OpenHarmony system version.
  "device_company": "bearpi",           --- Board vendor name, which is used to find the /device/board/bearpi directory during compilation.
  "board": "bearpi_hm_micro",           --- Board name, which is used to find the /device/board/bearpi/bearpi_hm_micro directory during compilation.
  "kernel_type": "liteos_a",            --- Kernel type. OpenHarmony supports multiple kernels, and one board may adapt to multiple kernels. Therefore, you need to specify a kernel for compilation.
  "kernel_version": "",                 --- Kernel version. One board may adapt to multiple Linux kernel versions. Therefore, you need to specify a kernel version for compilation.
  "subsystems": [ ]                     --- Subsystem to be built.
}

Add the config.gni file to the device/board/bearpi/bearpi_hm_micro/liteos_a directory to describe board and kernel information used by the product demo. The sample code is as follows:

# Kernel type, e.g. "linux", "liteos_a", "liteos_m".
kernel_type = "liteos_a"

# Kernel version.
kernel_version = ""

# Board CPU type, e.g. "cortex-a7", "riscv32".
board_cpu = "cortex-a7"

# Board arch, e.g.  "armv7-a", "rv32imac".
board_arch = ""

# Toolchain name used for system compiling.
# E.g. gcc-arm-none-eabi, arm-linux-harmonyeabi-gcc, ohos-clang,  riscv32-unknown-elf.
# Note: The default toolchain is "ohos-clang". It's not mandatory if you use the default toolchain.
board_toolchain = ""

# The toolchain path installed, it's not mandatory if you have added toolchain path to your ~/.bashrc.
board_toolchain_path = ""

# Compiler prefix.
board_toolchain_prefix = ""

# Compiler type, "gcc" or "clang".
board_toolchain_type = "clang"

# Board related common compile flags.
board_cflags = [
"-mfloat-abi=softfp",
"-mfpu=neon-vfpv4",
]
board_cxx_flags = [
"-mfloat-abi=softfp",
"-mfpu=neon-vfpv4",
]
board_ld_flags = []

# Board related headfiles search path.
board_include_dirs = []

# Board adapter dir for OHOS components.
board_adapter_dir = "//device/board/bearpi/bearpi_hm_micro/hal"

# Sysroot path.
board_configed_sysroot = ""

# Board storage type, it used for file system generation.
storage_type = "emmc"

Verify that the hb set configuration is correct. The hb set configuration is correct if the output information is as shown in the following figure.

Run hb set, enter the project root directory, and press Enter. The hb command will traverse all config.json files in the //vendor/<product_company>/<product_name> directory and list all available product compilation options. In config.json, product_name is used to display the product name, and device_company and board are used to associate the //device/board/<device_company>/<board> directory and match the <any_dir_name>/config.gni file. If multiple files are matched, the board adapts to multiple kernels. Then, kernel_type and kernel_version in config.json can be used to uniquely match kernel_type and kernel_version in config.gni, thus determining the board with a kernel to be compiled.

After you select a product and press Enter, a ohos_config.json file will be generated in the root directory. The file will list the product information to be compiled. You can also run the hb env command to view the selected precompilation environment variables.

Kernel Porting

Kernel porting requires LiteOS-A Kconfig adaptation, gn compilation and building, and minimum kernel startup adaptation.

For details about the porting procedure, see LiteOS-A kernel porting.

Kconfig Adaptation

Add the chip, product name, and vendor name configurations to //device/board/bearpi/bearpi_hm_micro/liteos_a/drivers/Kconfig.

source "../../device/soc/st/common/platform/Kconfig"

config PLATFORM
    string
    default "stm32mp157"      if PLATFORM_STM32MP157

config PRODUCT_NAME
    string "product name"
    default "bearpi_hm_micro" if PRODUCT_BEARPI_HM_MICRO

config DEVICE_COMPANY
    string "vendor name"
    default "st" if PLATFORM_STM32MP157
    
config TEE_ENABLE
    bool "Enable TEE"
    default n
    depends on  PLATFORM_STM32MP157
    help
        Enable teeos in platform

Add driver configurations to //device/soc/st/common/platform/Kconfig.

config DRIVERS_MMC
    depends on DRIVERS
    bool "Enable MMC"
    default y
    depends on DRIVERS && FS_VFS
    help
    Answer Y to enable LiteOS support MMC driver.

config DRIVERS_EMMC
    depends on DRIVERS_MMC && PLATFORM_STM32MP157 
    bool "Enable MMC0 support eMMC type"

config DRIVERS_HI3881
    bool "Enable Hi3881 Host driver"
    default n
    depends on DRIVERS_HDF_WIFI
    help
        Answer Y to enable Hi3881 Host driver.
config HW_RANDOM_ENABLE
        depends on DRIVERS_RANDOM 
        bool "Select hw random"
        default y
        help
        Answer Y to select hw random.

Enable related configurations in //vendor/bearpi/bearpi_hm_micro/kernel_configs/debug_tee.config.

...
LOSCFG_PLATFORM="stm32mp157"
LOSCFG_PRODUCT_NAME="bearpi_hm_micro"
LOSCFG_DEVICE_COMPANY="st"
# LOSCFG_PLATFORM_HI3516DV300 is not set
# LOSCFG_PLATFORM_HI3518EV300 is not set
# LOSCFG_PLATFORM_QEMU_ARM_VIRT_CA7 is not set
LOSCFG_PLATFORM_STM32MP157=y
LOSCFG_PRODUCT_BEARPI_HM_MICRO=y
LOSCFG_BOARD_CONFIG_PATH="device/board/bearpi/bearpi_hm_micro/liteos_a/board"
LOSCFG_TEE_ENABLE=y
...

GN Build Adaptation

Create BUILD.gn in //device/board/bearpi/bearpi_hm_micro/liteos_a and add the following code. This module depends on board, drivers, and hdf_config.

cmd = "if [ -f $product_path/hdf_config/BUILD.gn ]; then echo true; else echo false; fi"
HAVE_PRODUCT_CONFIG =
    exec_script("//build/lite/run_shell_cmd.py", [ cmd ], "value")

group("liteos_a") {
  deps = [
    "board",
    "drivers",
  ]
  if (HAVE_PRODUCT_CONFIG) {
    deps += [ "$product_path/hdf_config" ]
  } else {
    deps += [ "hdf_config" ]
  }
}

config("public") {
  configs = [
    "board:public",
    "drivers:public",
  ]
}

Create BUILD.gn in //device/board/bearpi/bearpi_hm_micro/liteos_a/board and add the following code: Compile os_adapt.c kernel startup code into the system.

import("//kernel/liteos_a/liteos.gni")

module_name = "bsp_config"

kernel_module(module_name) {
  sources = []
  if (defined(LOSCFG_PLATFORM_ADAPT)) {
    sources += [ "os_adapt/os_adapt.c" ]
  }
}

config("public") {
  include_dirs = [ "." ]
  include_dirs += [ "include" ]
  include_dirs += [ "$LITEOSTOPDIR/drivers/block/disk/include" ]
  include_dirs +=
      [ "$LITEOSTOPDIR/../../drivers/adapter/khdf/liteos/osal/include" ]
}

Create BUILD.gn in //device/board/bearpi/bearpi_hm_micro/liteos_a/drivers, add the following code, and compile the HDF driver under device/soc/st/common/platform into the system:

import("//drivers/adapter/khdf/liteos/hdf.gni")

group("drivers") {
  public_deps = [ "//device/soc/st/common/platform:drivers" ]
}

config("public") {
  configs = [ "//device/soc/st/common/platform:public" ]
}

Create BUILD.gn in //vendor/bearpi/bearpi_hm_micro/hdf_config, add the following code, and compile the HCS configuration file into the system:

module_switch = defined(LOSCFG_DRIVERS_HDF) && !defined(LOSCFG_DRIVERS_HDF_TEST)
module_name = "libhdf_config"
hdf_driver(module_name) {
  hcs_sources = [ "hdf.hcs" ]
}

group("hdf_config") {
  public_deps = [ ":$module_name" ]
  deps = [
    "hdf_test",
    "hdf_test/hcs_macro_test",
  ]
}

Kernel Startup Adaptation

Add the following kernel startup code to //device/board/bearpi/bearpi_hm_micro/liteos_a/board/os_adapt.c. For details, see LiteOS-A kernel porting.

...
void SystemInit(void)
{
#ifdef LOSCFG_DRIVERS_RANDOM
    dprintf("dev random init ...\n");
    Mp1xxRngInit();
#endif
#ifdef LOSCFG_DRIVERS_MEM
    dprintf("mem dev init ...\n");
    extern int mem_dev_register(void);
    mem_dev_register();
#endif

    dprintf("Date:%s.\n", __DATE__);
    dprintf("Time:%s.\n", __TIME__);

#ifdef LOSCFG_DRIVERS_HDF
    dprintf("DeviceManagerStart start ...\n");
    if (DeviceManagerStart()) {
        PRINT_ERR("No drivers need load by hdf manager!");
    }
    dprintf("DeviceManagerStart end ...\n");
#endif
    net_init();

#ifdef LOSCFG_PLATFORM_ROOTFS
    dprintf("OsMountRootfs start ...\n");
    if (LOS_GetCmdLine()) {
        dprintf("get cmdline error!\n");
    }
    if (LOS_ParseBootargs()) {
        dprintf("parse bootargs error!\n");
    }
    if (OsMountRootfs()) {
        dprintf("mount rootfs error!\n");
    }
    dprintf("OsMountRootfs end ...\n");
#endif

    dprintf("Before PLATFORM_UART ...\n");

#ifdef LOSCFG_DRIVERS_HDF_PLATFORM_UART
    if (virtual_serial_init(TTY_DEVICE) != 0) {
        PRINT_ERR("virtual_serial_init failed");
    }
    if (system_console_init(SERIAL) != 0) {
        PRINT_ERR("system_console_init failed\n");
    }
#endif

    dprintf("After PLATFORM_UART ...\n");

    if (OsUserInitProcess()) {
        PRINT_ERR("Create user init process failed!\n");
        return;
    }
    dprintf("cat log shell end\n");
    return;
}
...

Board-Level OS Porting

Porting the HDF Driver for the SoC Platform

Driver adaptation files are stored in device/soc/st/common/platform and are loaded using the HDF mechanism. This section uses GPIO driver adaptation as an example.

Describe the building adaptation of the stm32mp1xx gpio driver in the //device/soc/st/common/platform/gpio/BUILD.gn file. The sample code is as follows:

module_switch = defined(LOSCFG_DRIVERS_HDF_PLATFORM_GPIO)	 --- If the GPIO configuration switch of the HDF is enabled, the following is built:
module_name = get_path_info(rebase_path("."), "name")

hdf_driver("hdf_gpio") {
    sources = [ "stm32mp1_gpio.c" ]        --- GPIO driver source file
    include_dirs = [                       --- Dependent .h path
      "." ,
      "../stm32mp1xx_hal/STM32MP1xx_HAL_Driver/Inc",
    ]
}

Describe the source code adaptation of the stm32mp1xx gpio driver in the //device/soc/st/common/platform/gpio/stm32mp1_gpio.c file. First, load the basic driver adaptation framework based on the HDF driver framework of OpenHarmony, as shown below:

struct HdfDriverEntry g_GpioDriverEntry = {
    .moduleVersion = 1,
    .moduleName = "HDF_PLATFORM_GPIO",
    .Bind = GpioDriverBind,
    .Init = GpioDriverInit,
    .Release = GpioDriverRelease,
};
HDF_INIT(g_GpioDriverEntry); 	 --- Load the GPIO driver using HDF_INIT.

Add the GPIO hardware description file gpio_config.hcs to //device/soc/st/stm32mp1xx/sdk_liteos/hdf_config/gpio, and add private configuration information of the driver to the file.

root {
    platform {
        gpio_config {
            controller_0x50002000 {
                match_attr = "st_stm32mp1_gpio";
                groupNum = 11;
                bitNum = 16;
                gpioRegBase = 0x50002000;
                gpioRegStep = 0x1000;
                irqRegBase = 0x5000D000;
                irqRegStep = 0x400;
            }
        }
    }
}

Configure the product load driver. All device information of the product is defined in the source code file //vendor/bearpi/bearpi_hm_micro/hdf_config/device_info/device_info.hcs.

Add the platform driver to the host of the platform.

NOTE

moduleName must be the same as that defined in the driver file, and deviceMatchAttr must be the same as match_attr defined in the driver's private configuration information file gpio_config.hcs.

root {
    ...
    platform :: host {
         device_gpio :: device {
             device0 :: deviceNode {
                 policy = 2;
                 priority = 10;
                 permission = 0644;
                 moduleName = "HDF_PLATFORM_GPIO_MANAGER";
                 serviceName = "HDF_PLATFORM_GPIO_MANAGER";
             }
             device1 :: deviceNode {
                 policy = 0;
                 priority = 10;
                 permission = 0644;
                 moduleName = "HDF_PLATFORM_GPIO";
                 serviceName = "HDF_PLATFORM_GPIO";
                 deviceMatchAttr = "st_stm32mp1_gpio";
             }
         }
    }
}

Complete driver code. Configuration information in gpio_config.hcs will be loaded in GpioDriverInit.

static int32_t GpioDriverInit(struct HdfDeviceObject *device)
{

    int32_t ret;
    struct Mp1xxGpioCntlr *stm32gpio = &g_Mp1xxGpioCntlr;

    dprintf("%s: Enter", __func__);
    if (device == NULL || device->property == NULL) {
        HDF_LOGE("%s: device or property NULL!", __func__);
        return HDF_ERR_INVALID_OBJECT;
    }
    // Obtain property data.
    ret = Mp1xxGpioReadDrs(stm32gpio, device->property);
    if (ret != HDF_SUCCESS) {
        HDF_LOGE("%s: get gpio device resource fail:%d", __func__, ret);
        return ret;
    }
    ...
}

OpenHarmony Subsystem Adaptation

To adapt OpenHarmony subsystems, you only need to add related subsystems and components to config.json, so that the components can be included in the compilation by the compilation system.

Startup Subsystem Adaptation

For the startup subsystem, adapt the bootstrap_lite, syspara_lite, appspawn_lite, and init components. Add the corresponding configuration items to the vendor/bearpi/bearpi_hm_micro/config.json file, as shown below:

    {
    "subsystem": "startup",
    "components": [
        { "component": "syspara_lite", "features":[] },
        { "component": "bootstrap_lite", "features":[] },
        { "component": "appspawn_lite", "features":[] },
        { "component": "init", "features":[] }
     ]
    },

The system will be started according to startup configurations in the //vendor/bearpi/bearpi_hm_micro/init_configs file.

DFX Subsystem Adaptation

To adapt the DFX subsystem, you need to add the hilog_featured_lite and hidumper_lite components to the config.json file.

    {
        "subsystem": "hiviewdfx",
        "components": [
            { "component": "hilog_featured_lite", "features":[] },
            { "component": "hidumper_lite", "features":[] }
        ]
    },

System Service Management Subsystem Adaptation

To adapt the system service management subsystem, you need to add the samgr_lite, safwk_lite, and dmsfwk_lite components to the config.json file.

    {
    "subsystem": "distributed_schedule",
    "components": [
        { "component": "samgr_lite", "features":[] },
        { "component": "safwk_lite", "features":[] },
        { "component": "dmsfwk_lite", "features":[] }
    ]
    },

Security Subsystem Adaptation

To adapt the security subsystem, you need to add the permission_lite, appverify, device_auth, and huks components to the config.json file.

    {
    "subsystem": "security",
    "components": [
        { "component": "permission_lite", "features":[] },
        { "component": "appverify", "features":[] },
        { "component": "device_auth", "features":[] },
        { "component": "huks", "features":
        [
            "huks_config_file = \"hks_config_small.h\""
        ]
        }
    ]
    },

utils Subsystem Adaptation

To adapt the utils subsystem, you need to add the kv_store and os_dump components to the config.json file.

      {
        "subsystem": "utils",
        "components": [
          { "component": "kv_store", "features":[] },
          { "component": "os_dump", "features":[] }
        ]
      },

Graphics Subsystem Adaptation

To adapt the graphics subsystem, you need to add the graphic_utils component to the config.json file.

      {
        "subsystem": "graphic",
        "components": [
          { "component": "graphic_utils",           
            "features": [ "enable_ohos_graphic_utils_product_config = true"
             ]
          },
          { "component": "graphic_hals", "features":[] },
          { "component": "ui", "features":[ "enable_graphic_font = true","enable_video_component=false"] },
          { "component": "surface", "features":[] },
          { "component": "wms", "features":[] }
        ]
      },

For details about graphic configuration, see //vendor/bearpi/bearpi_hm_micro/graphic_config/product_graphic_lite_config.h.

ArkUI Subsystem Adaptation

To adapt the ArkUI subsystem, you need to add the ace_engine_lite component to the config.json file.

    {
        "subsystem": "arkui",
        "components": [
        {
            "component": "ace_engine_lite",
            "features": [
            "enable_ohos_ace_engine_lite_product_config = true"
            ]
        }
        ]
    },

For details about ace_engine_lite configuration, see //vendor/bearpi/bearpi_hm_micro/ace_lite_config/product_acelite_config.h.

aafwk Subsystem Adaptation

To adapt the aafwk subsystem, you need to add the aafwk_lite component to the config.json file.

    {
    "subsystem": "aafwk",
    "components": [
        {
        "component": "aafwk_lite",
        "features": [
            "enable_ohos_appexecfwk_feature_ability = true"	 --- The FA feature is supported, that is, the graphics capability is included.
        ]
        }
    ]
    },

appexecfwk Subsystem Adaptation

To adapt the appexecfwk subsystem, you need to add the appexecfwk_lite component to the config.json file.

    {
    "subsystem": "appexecfwk",
    "components": [
        {
        "component": "appexecfwk_lite"
        }
    ]
    },