HDF驱动框架探路（openharmony最新源码，打通应用态到内核态） _内核态

天下之事常成于困约，而败于奢靡。这篇文章主要讲述HDF驱动框架探路：openharmony最新源码，打通应用态到内核态相关的知识，希望能为你提供帮助。
【本文正在参与优质创作者激励】
老规矩还是将最终希望跑出来的效果放出来。如下：

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@toc
前言

1.首先本文章的源码是2021.11.25拉的openharmony的master分支。之前也有一些大神基于3516应用态打通到了内核态，不过都很久远了，尤其是3.0LTS发布之后，整个框架都改动过了，按照大神们的操作我这边基于最新的源码都没有测试成功。有大佬可以留言指导一拨儿。
2.本文章是基于Hi3516轻量系统来打造的。应用态打通内核态的总体框架图

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从上图可以很直观的看出驱动开发的过程中基于linux开发和基于openharmony开发的最大区别

1.linux驱动开发中会涉及到应用层的glic等，以及驱动层的内核函数调用，但是在openharmony这些以及都被HDF框架给隐藏起来了，所以我们只需要根据HDF框架来进行openharmony框架开发，就可以了。
2.openharmony应用层其实是调用了HDF框架的驱动消息机制 1.应用程序 2.1 应用层业务代码
1.在源码根目录下新建myapp目录
2.然后进入myapp目录新建helloworld_test.c，然后将下列代码拷贝入内
#include < fcntl.h> #include < sys/stat.h> #include < sys/ioctl.h> #include < unistd.h> #include "hdf_log.h" #include "hdf_sbuf.h" #include "hdf_io_service_if.h"

#define HDF_LOG_TAG " sample_test"
#define SAMPLE_SERVICE_NAME " GPIO_TEST"
#define SAMPLE_WRITE_READ 0
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_LOGE(" %s: dev event received: %u %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 = https://www.songbingjia.com/android/HdfSBufObtainDefaultSize();
if (data =https://www.songbingjia.com/android/= 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 = https://www.songbingjia.com/android/0; if (!HdfSbufReadInt32(reply, & replyData)) { HDF_LOGE("fail to get service call reply"); ret = HDF_ERR_INVALID_OBJECT; goto out; } HDF_LOGE("Get reply is: %d", replyData);

【HDF驱动框架探路（openharmony最新源码，打通应用态到内核态）】out:
HdfSBufRecycle(data);
HdfSBufRecycle(reply);
return ret;
}
int main()
{
char sendData = https://www.songbingjia.com/android/" hi" ;
struct HdfIoService serv = HdfIoServiceBind(SAMPLE_SERVICE_NAME);
if (serv == NULL) {
HDF_LOGE(" fail to get service %s" , SAMPLE_SERVICE_NAME);
return HDF_FAILURE;
}
HDF_LOGE(" success to get service %s" , SAMPLE_SERVICE_NAME);

static struct HdfDevEventlistener listener = { .callBack = OnDevEventReceived, .priv ="Service0" }; if (HdfDeviceRegisterEventListener(serv, & listener) != HDF_SUCCESS) { HDF_LOGE("fail to register event listener"); return HDF_FAILURE; } HDF_LOGE("success to register event listener"); if (SendEvent(serv, sendData)) { HDF_LOGE("fail to send event"); return HDF_FAILURE; }/* wait for event receive event finishing */ while (g_replyFlag == 0) { sleep(1); }if (HdfDeviceUnregisterEventListener(serv, & listener)) { HDF_LOGE("fail tounregister listener"); return HDF_FAILURE; }HdfIoServiceRecycle(serv); return HDF_SUCCESS;

}

## 1.2 应用层业务代码以可执行文件编译进系统 - 进入源码目录找到drivers/adapter/uhdf/manager/BUILD.gn 文件，然后在文件末尾拷贝下述代码。```c HDF_FRAMEWORKS = "//drivers/framework"executable("helloworld_test") { sources = ["//myapp/helloworld_test.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", ] }

2.驱动代码这里驱动是直接引用了源码中已经存在的一个驱动程序：GPIO_TEST
2.1 驱动业务层代码