OpenHarmony基于HDF简单驱动开发实例

背景

• OpenHarmony-3.0-LTS
• qemu_small_system_demo
• liteos_a
• qemu

添加配置

device/qemu/arm_virt/liteos_a/hdf_config/device_info/device_info.hcs

device_info 新增：

sample_host :: host {
    hostName = "sample_host";
    sample_device :: device {
        device0 :: deviceNode {
            policy = 2;
            priority = 100;
            preload = 1;
            permission = 0664;
            moduleName = "sample_driver";
            serviceName = "sample_service";
        }
    }
}

添加驱动代码

目录：device/qemu/arm_virt/liteos_a/drivers

新建驱动实现

mkdir sample_driver
vim sample_driver/sample_driver.c

#include <fcntl.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include "hdf_log.h"
#include "hdf_base.h"
#include "hdf_device_desc.h"

#define HDF_LOG_TAG sample_driver

#define SAMPLE_WRITE_READ 123

static int32_t HdfSampleDriverDispatch(  \
    struct HdfDeviceIoClient *client, int id, struct HdfSBuf *data, struct HdfSBuf *reply)
{
    HDF_LOGI("%{public}s: received cmd %{public}d", __func__, id);
    if (id == SAMPLE_WRITE_READ) {
        const char *readData = HdfSbufReadString(data);
        if (readData != NULL) {
            HDF_LOGE("%{public}s: read data is: %{public}s", __func__, readData);
        }
        if (!HdfSbufWriteInt32(reply, INT32_MAX)) {
            HDF_LOGE("%{public}s: reply int32 fail", __func__);
        }
        return HdfDeviceSendEvent(client->device, id, data);
    }
    return HDF_FAILURE;
}

static void HdfSampleDriverRelease(struct HdfDeviceObject *deviceObject)
{
    // release resources here
    return;
}

static int HdfSampleDriverBind(struct HdfDeviceObject *deviceObject)
{
    if (deviceObject == NULL) {
        return HDF_FAILURE;
    }
    static struct IDeviceIoService testService = {
        .Dispatch = HdfSampleDriverDispatch,
    };
    deviceObject->service = &testService;
    return HDF_SUCCESS;
}

static int HdfSampleDriverInit(struct HdfDeviceObject *deviceObject)
{
    if (deviceObject == NULL) {
        HDF_LOGE("%{public}s::ptr is null!", __func__);
        return HDF_FAILURE;
    }
    HDF_LOGI("Sample driver Init success");
    return HDF_SUCCESS;
}

static struct HdfDriverEntry g_sampleDriverEntry = {
    .moduleVersion = 1,
    .moduleName = "sample_driver",
    .Bind = HdfSampleDriverBind,
    .Init = HdfSampleDriverInit,
    .Release = HdfSampleDriverRelease,
};

HDF_INIT(g_sampleDriverEntry);

新建Makefile和BUILD.gn

新建Makefile和BUILD.gn,可参考其他平台，例如 device/hisilicon/drivers/rtc/

Makefile：

include $(LITEOSTOPDIR)/config.mk
include $(LITEOSTOPDIR)/../../drivers/adapter/khdf/liteos/lite.mk

MODULE_NAME := sample_driver

LOCAL_CFLAGS += $(HDF_INCLUDE)

LOCAL_SRCS += sample_driver.c

LOCAL_CFLAGS += -fstack-protector-strong -Wextra -Wall -Werror -fsigned-char -fno-strict-aliasing -fno-common

include $(HDF_DRIVER)

BUILD.gn：

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

#module_switch = defined(LOSCFG_DRIVERS_HDF_PLATFORM_RTC)
module_name = "sample_driver"
hdf_driver(module_name) {
  sources = [ "sample_driver.c" ]
}

修改上层BUILD.gn

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

group("drivers") {
  public_deps = [ "../../../drivers" ]

  #新增
  deps = [
    "sample_driver",
  ]

}

config("public") {
  configs = [ "../../../drivers:public" ]
}

编写驱动交互代码

目录：vendor/ohemu/qemu_small_system_demo/

新建用户代码实现

mkdir hdf_test
vim hdf_test/sample_service.c

#include <fcntl.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include "hdf_log.h"
#include "hdf_io_service_if.h"

#define HDF_LOG_TAG sample_test
#define SAMPLE_SERVICE_NAME "sample_service"

#define SAMPLE_WRITE_READ 123

int g_replyFlag = 0;

static int OnDevEventReceived(void *priv,  uint32_t id, struct HdfSBuf *data)
{
    const char *string = HdfSbufReadString(data);
    if (string == NULL) {
        HDF_LOGE("fail to read string in event data");
        g_replyFlag = 1;
        return HDF_FAILURE;
    }
    HDF_LOGI("%{public}s: dev event received: %{public}u %{public}s",  (char *)priv, id, string);
    g_replyFlag = 1;
    return HDF_SUCCESS;
}

static int SendEvent(struct HdfIoService *serv, char *eventData)
{
    int ret = 0;
    struct HdfSBuf *data = HdfSBufObtainDefaultSize();
    if (data == NULL) {
        HDF_LOGE("fail to obtain sbuf data");
        return 1;
    }

    struct HdfSBuf *reply = HdfSBufObtainDefaultSize();
    if (reply == NULL) {
        HDF_LOGE("fail to obtain sbuf reply");
        ret = HDF_DEV_ERR_NO_MEMORY;
        goto out;
    }

    if (!HdfSbufWriteString(data, eventData)) {
        HDF_LOGE("fail to write sbuf");
        ret = HDF_FAILURE;
        goto out;
    }

    ret = serv->dispatcher->Dispatch(&serv->object, SAMPLE_WRITE_READ, data, reply);
    if (ret != HDF_SUCCESS) {
        HDF_LOGE("fail to send service call");
        goto out;
    }

    int replyData = 0;
    if (!HdfSbufReadInt32(reply, &replyData)) {
        HDF_LOGE("fail to get service call reply");
        ret = HDF_ERR_INVALID_OBJECT;
        goto out;
    }
    HDF_LOGI("Get reply is: %{public}d", replyData);
out:
    HdfSBufRecycle(data);
    HdfSBufRecycle(reply);
    return ret;
}

int main()
{
    char *sendData = "default event info";

    HDF_LOGI(SAMPLE_SERVICE_NAME "start");

    struct HdfIoService *serv = HdfIoServiceBind(SAMPLE_SERVICE_NAME);
    if (serv == NULL) {
        HDF_LOGE("fail to get service %s", SAMPLE_SERVICE_NAME);
        return HDF_FAILURE;
    }

    static struct HdfDevEventlistener listener = {
        .callBack = OnDevEventReceived,
        .priv ="Service0"
    };

    if (HdfDeviceRegisterEventListener(serv, &listener) != HDF_SUCCESS) {
        HDF_LOGE("fail to register event listener");
        return HDF_FAILURE;
    }
    if (SendEvent(serv, sendData)) {
        HDF_LOGE("fail to send event");
        return HDF_FAILURE;
    }

    while (g_replyFlag == 0) {
        sleep(1);
    }

    if (HdfDeviceUnregisterEventListener(serv, &listener)) {
        HDF_LOGE("fail to  unregister listener");
        return HDF_FAILURE;
    }

    HdfIoServiceRecycle(serv);
    return HDF_SUCCESS;
}

新建BUILD.gn

vim sample_service/BUILD.gn，可参考huawei/hdf/sample/platform/uart/dispatch/BUILD.gn

import("//build/lite/config/component/lite_component.gni")
HDF_FRAMEWORKS = "//drivers/framework"

lite_component("hdf_test") {
  features = [ ":sample_service" ]
}

executable("sample_service") {
  sources = [ "sample_service.c" ]

  include_dirs = [
    "$HDF_FRAMEWORKS/ability/sbuf/include",
    "$HDF_FRAMEWORKS/core/shared/include",
    "$HDF_FRAMEWORKS/core/host/include",
    "$HDF_FRAMEWORKS/core/master/include",
    "$HDF_FRAMEWORKS/include/core",
    "$HDF_FRAMEWORKS/include/utils",
    "$HDF_FRAMEWORKS/utils/include",
    "$HDF_FRAMEWORKS/include/osal",
    "//drivers/adapter/uhdf/posix/include",
    "//third_party/bounds_checking_function/include",
    "//base/hiviewdfx/hilog_lite/interfaces/native/innerkits",
  ]

  deps = [
    "//base/hiviewdfx/hilog_lite/frameworks/featured:hilog_shared",
    "//drivers/adapter/uhdf/manager:hdf_core",
    "//drivers/adapter/uhdf/posix:hdf_posix_osal",
  ]

  public_deps = [ "//third_party/bounds_checking_function:libsec_shared" ]
  defines = [ "__USER__" ]

  cflags = [
    "-Wall",
    "-Wextra",
    "-Wno-format",
    "-Wno-format-extra-args",
  ]

}

说明： 用户态应用程序使用了HDF框架中的消息发送接口，因此在编译用户态程序的过程中需要依赖HDF框架对外提供的hdf_core和osal的动态库，在gn编译文件中添加如下依赖项：

deps = [
​ "//drivers/hdf_core/adapter/uhdf/manager:hdf_core",
​ "//drivers/hdf_core/adapter/uhdf/posix:hdf_posix_osal",
]

修改上层BUILD.gn

group("qemu_small_system_demo") {
  deps = [
    "apps",
    "init_configs",
    "hdf_test",  #新增
  ]
}

以上都是趟过了许多坑后再跑通的

编译测试

使用 hb 重新编译镜像，会生成对应带新增驱动的内核和带用户程序的镜像

#编译
hb clean
hb build

运行新编译的镜像

#运行qemu
./vendor/ohemu/qemu_small_system_demo/patches/qemu-run

注： 需要修改上述脚本中的 rebuild=yes，让其每次都重新生成qemu镜像

开机log有如下打印，说明驱动已加载成功，并且在/dev/hdf/下面会生成 sample_service的节点：

...

01-01 00:00:00.119 2 4 W 02500/driver_loader: failed to load node, property is null, match attr is: 
01-01 00:00:00.119 2 4 I 02500/sample_driver: Sample driver Init success
01-01 00:00:00.119 2 4 I 02500/osal_cdev: OsalRegisterCdev:register /dev/hdf/sample_service
01-01 00:00:00.119 2 4 D 02500/devmgr_service: DevmgrServiceUpdateStatus host:sample_host 0 device:sample_service 0 status:1

...

OHOS:/$ ls /dev/hdf/                                                           
dev_mgr  event2  hdf_input_event1  input_dev_manager  sample_service 

运行测试应用 sample_service，会有如下打印：

OHOS:/$ sample_service                                                         
01-01 00:00:59.059 10 44 I 02500/sample_test: sample_servicestart
01-01 00:00:59.063 10 44 I 02500/sample_driver: HdfSampleDriverDispatch: received cmd 123
01-01 00:00:59.063 10 44 E 02500/sample_driver: HdfSampleDriverDispatch: read data is: default event info
01-01 00:00:59.064 10 44 I 02500/sample_test: Get reply is: 2147483647
01-01 00:00:59.068 10 45 I 02500/sample_test: Service0: dev event received: 123 default event info
01-01 00:01:00.065 10 44 D 02500/hdf_syscall_adapter: ioctl send poll thread(4) exit event, ret=0
OHOS:/$ 01-01 00:01:00.066 10 45 I 02500/hdf_syscall_adapter: event listener task received exit event
01-01 00:01:00.066 10 45 I 02500/hdf_syscall_adapter: event listener task exit
01-01 00:01:00.067 10 44 I 02500/hdf_syscall_adapter: poll thread exited
^C
OHOS:/$ ^C

参考

社区官方文档：HDF驱动开发流程