android P hal开发demo（改）

作者: 周鹤_006d | 来源:发表于2020-04-10 15:34 被阅读0次

android P hal开发demo（改）
android P hal开发demo
Android HAL层开发
Android 字符驱动#1#开发Android硬件抽象层(HA
Android HAL
Android硬件抽象层HAL总结
Android分层
android HAL例子分析
Android 系统开发（2）--Android Treble
Android 文件目录

注：在没有特殊说明下，所有操作都在aosp目录下进行。

1.编译(基于ubuntu16.04)

1.1先安装repo工具(参考https://mirrors.tuna.tsinghua.edu.cn/help/git-repo/)

1.2代码下载

到内网10.19.118.212的/home/neusoft/android_source/zhangshuang文件夹下(用户名:neusoft,密码:root)用smb把aosp_9_back.tar.gz拷贝到任意目录，然后解压

或者

$ repo init -u https://android.googlesource.com/platform/manifest -b android-9.0.0_r39 --depth=1

$ repo sync

1.3编译

$ source build/envsetup.sh

// 因为我们要实验car的版本

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$ lunch 10

$ make -j8

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1.4启动模拟器

编译成功之后，输入命令emulator可以启动模拟器(模拟器更多指令参数参照emulator -help)

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2.HAL服务端开发

2.1.编写hal文件

在AOSP代码的目录 hardware/interfaces/中新建test/1.0/，在此目录中新建 ITest.hal，内容：

package android.hardware.test@1.0;
interface ITest{
    helloWorld(string name) generates (string result);
};

2.2.使用hidl-gen生成对应的c++文件

2.2.1编译hidl-gen工具

make hidl-gen

2.2.2设置临时变量

PACKAGE=android.hardware.test@1.0
LOC=hardware/interfaces/test/1.0/default

2.2.3生成c++文件

(在aosp根目录下执行,source完之后执行croot可以回到aosp根目录)

hidl-gen -o $LOC -Lc++-impl -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport $PACKAGE

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2.2.4生成Android.bp文件

hidl-gen -o $LOC -Landroidbp-impl -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport $PACKAGE

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2.2.5生成1.0目录下的Android.bp

执行./hardware/interfaces/update-makefiles.sh

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2.3实现c++文件

2.3.1Test.h文件实现passthrough模式

#ifndef ANDROID_HARDWARE_TEST_V1_0_TEST_H
#define ANDROID_HARDWARE_TEST_V1_0_TEST_H
#include <android/hardware/test/1.0/ITest.h>
#include <hidl/MQDescriptor.h>
#include <hidl/Status.h>
namespace android {
namespace hardware {
namespace test {
namespace V1_0 {
namespace implementation {
using ::android::hardware::hidl_array;
using ::android::hardware::hidl_memory;
using ::android::hardware::hidl_string;
using ::android::hardware::hidl_vec;
using ::android::hardware::Return;
using ::android::hardware::Void;
using ::android::sp;
struct Test : public ITest {
    // Methods from ::android::hardware::test::V1_0::ITest follow.
    Return<void> helloWorld(const hidl_string& name, helloWorld_cb _hidl_cb) override;
    // Methods from ::android::hidl::base::V1_0::IBase follow.
};
// FIXME: most likely delete, this is only for passthrough implementations
extern "C" ITest* HIDL_FETCH_ITest(const char* name);
}  // namespace implementation
}  // namespace V1_0
}  // namespace test
}  // namespace hardware
}  // namespace android
#endif  // ANDROID_HARDWARE_TEST_V1_0_TEST_H

2.3.2Test.cpp实现

#include "Test.h"
namespace android {
namespace hardware {
namespace test {
namespace V1_0 {
namespace implementation {
// Methods from ::android::hardware::test::V1_0::ITest follow.
Return<void> Test::helloWorld(const hidl_string& name, helloWorld_cb _hidl_cb) {
    // TODO implement
    // 做了简单实现 start @{
    printf("Test helloWorld");
    char buf[100];
    memset(buf, 0, 100);
    snprintf(buf, 100, "Hello World, %s", name.c_str());
    hidl_string result(buf);
    _hidl_cb(result);
    // 做了简单实现 end @}
    return Void();
}
// Methods from ::android::hidl::base::V1_0::IBase follow.
ITest* HIDL_FETCH_ITest(const char* /* name */) {
    return new Test();
}
}  // namespace implementation
}  // namespace V1_0
}  // namespace test
}  // namespace hardware
}  // namespace android

2.4添加启动service

在hardware/interfaces/test/1.0/default目录下新建android.hardware.test@1.0-service.rc 启动脚本

service test_hal_service /vendor/bin/hw/android.hardware.test@1.0-service
    class hal
    user system
    group system

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2.5新建service.cpp，采用直通式

#define LOG_TAG "android.hardware.test@1.0-service"
#include <android/hardware/test/1.0/ITest.h>
#include <hidl/LegacySupport.h>
using android::hardware::test::V1_0::ITest;
using android::hardware::defaultPassthroughServiceImplementation;;
//passthrough mode
int main() {
  return defaultPassthroughServiceImplementation<ITest>();
//passthrough mode
}

image

2.6修改hardware/interfaces/test/1.0/default目录下的Android.bp

cc_library_shared {
    name: "android.hardware.test@1.0-impl",
    relative_install_path: "hw",
    proprietary: true,
    srcs: [
        "Test.cpp",
    ],
    shared_libs: [
        "libhidlbase",
        "libhidltransport",
        "libutils",
        "android.hardware.test@1.0",
    ],
}
cc_binary {
    name: "android.hardware.test@1.0-service",
    defaults: ["hidl_defaults"],
    proprietary: true,
    relative_install_path: "hw",
    srcs: ["service.cpp"],
    init_rc: ["android.hardware.test@1.0-service.rc"],
    shared_libs: [
        "libhidlbase",
        "libhidltransport",
        "libutils",
        "liblog",
        "android.hardware.test@1.0",
    ],
}

2.7调用update-makefiles.sh更新一下

执行./hardware/interfaces/update-makefiles.sh

image

2.8.编译

mmm ./hardware/interfaces/test/1.0

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3.VNDK相关(https://chendongqi.me/2019/09/01/hidl-binderizing-passthrough/)

build/make/target/product/vndk/28.txt增加一行

2020-04-13 09-59-56屏幕截图.png

build/make/target/product/vndk/current.txt增加一行

2020-04-13 09-59-56屏幕截图.png

4.device部分

为了保证新增的hidl是可以被客户端访问到的，由于此次要使用emulator验证，并且lunch的是aosp_car_x86_64-eng所以在device找到下面目录device/generic/car/common/manifest.xml添加如下内容:

    <hal format="hidl">
        <name>android.hardware.test</name>
        <transport>hwbinder</transport>
        <version>1.0</version>
        <interface>
            <name>ITest</name>
            <instance>default</instance>
        </interface>
    </hal>

5.完整编译

在aosp根目录执行make编译出相应的镜像

5.1错误处理

Added VNDK-core: android.hardware.power@1.3.so
 error: VNDK library list has been changed.
        Changing the VNDK library list is not allowed in API locked branches.
[  2% 13/554] build out/target/product/g...pp_intermediates/oat/x86_64/package.odex
ninja: build stopped: subcommand failed.
09:47:07 ninja failed with: exit status 1

#### failed to build some targets (14 seconds) ####

将build/make/target/product/vndk/28.txt
build/make/target/product/vndk/current.txt
与out/target/product/generic_x86_64/obj/PACKAGING/vndk_intermediates/libs.txt
文件比较，将libs.txt中的内容同步到28.txt和current.txt文件中。

2020-04-13 10-49-40屏幕截图.png

6.启动服务

6.1启动模拟器

// -writable-system让模拟器可写，-selinux disabled跳过selinux检查
emulator -writable-system -selinux disabled

执行如下命令

// 获取root权限

adb root

// 获取模拟器写权限

adb remount

// 进入模拟器控制台

adb shell

// 启动hal服务

vendor/bin/hw/android.hardware.test@1.0-service &

image

6.2查看服务是否启动成功

ps -A |grep "test"

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7.客户端测试程序

7.1.c++客户端

7.1.1内容编写

在packages/apps目录下新建testApp/native文件夹,创建Android.mk,内容如下:

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)
LOCAL_PROPRIETARY_MODULE := true
LOCAL_MODULE := test
LOCAL_SRC_FILES := \
client.cpp \

LOCAL_SHARED_LIBRARIES := \
liblog \
libhidlbase \
libutils \
android.hardware.test@1.0 \

include $(BUILD_EXECUTABLE)

创建client.cpp内容如下:

# include <android/hardware/test/1.0/ITest.h>
# include <hidl/Status.h>
# include <hidl/LegacySupport.h>
# include <utils/misc.h>
# include <hidl/HidlSupport.h>
# include <stdio.h>
using android::hardware::test::V1_0::ITest;
using android::sp;
using android::hardware::hidl_string;
int main()
{
    fprintf(stderr,"%s\n" , "start");
    android::sp<ITest> service = ITest::getService();
    printf("%s\n", "service");
    if(service == nullptr) {
        printf("Failed to get service\n");
        return -1;
    }
    service->helloWorld("test", [&](hidl_string result) {
                printf("%s\n", result.c_str());
        });
    printf("%s\n", "end");
    return 0;
}