目录
6. 在1.0/default/下面生成Android.bp
8. 在主目录android下执行如下命令生成current.txt
9. 在1.0/default/下添加vendor.qti.hardware.customizehidl-service.rc
10. 在1.0/default/下添加vendor.qti.hardware.customizehidl-service.xml
11. 在device/qcom/common/vendor_compatibility_matrix.xml中添加如下内容
12. 在1.0/default/下添加service.cpp
HIDL 这个机制的目的，主要是为了把框架（framework）与 HAL 进行隔离，使得框架部分可以直接被覆盖、更新，而不需要重新对 HAL 进行编译。HAL 的部分将会放在设备的 /vendor 分区中，并且是由设备供应商（vendors）或 SOC 制造商来构建。这使得框架部分可以通过 OTA 方式更新，同时不需要重新编译 HAL。
这种设计被称为Treble机制，从Android 8.0引入。在此之前framework需要调用dlopen打开HAL编译的.so才能和HAL 层通信，这样framework 与 HAL 处在同一个进程 , 两者耦合严重，导致版本升级时供应商需要做大量的适配工作。
Treble机制解决目前Android 版本之间升级麻烦的问题，将OEM适配的部分vendor与google 对android 大框架升级的部分system部分做了分离，一旦适配了一个版本的vendor信息之后，之后的版本再进行升级时，直接升级system即可，这个就不会给OEM厂商升级带来太大的工作量，直接升级最新功能，可以解决目前市面上Android版本过于凌乱的问题。
Treble机制在Vendor分区中有两种模式，直通模式(Passthrough)和绑定模式（Binderized），大致框架图如下，对于Android O之前的设备，对应图1，对于从之前的设备升级到O的版本，对应图2、图3. 对于直接基于Android O开发的设备，对应图4。
一般新增HIDL Service都是在vendor目录下新增，最好在自己的产品名下新增文件夹，创建相应的HIDL服务，假设目前要在qcom下新增HIDL服务，流程如下：
如何新增HIDL服务
1.新增hidl服务文件夹
在vendor/qcom/opensource/interfaces下新增文件夹，这里新增customizehidl文件夹
在customizehidl下新建1.0文件夹
在1.0下新增default文件夹
2. 新增.hal文件
在customizehidl下新增ICustomizehidl.hal以及types.hal文件
vendor/qcom/opensource/interfaces/ICustomizehidl.hal
package [email protected];
interface ICustomizeHidl{
resetOption(int32_t side) generates (Result result);
};vendor/qcom/opensource/interfaces/types.hal
package [email protected];
enum Result : int32_t {
OK = 0,
ERR,
OUT_OF_RANGE,
};3. 编译hidl-gen
source build/envsetup.sh
lunch xx
make hidl-gen
这样后面就可以用hidl-gen工具了，
4. 配置hidl的package root
PACKAGE=vendor.qti.hardware.customizehidl@1.0
LOC=vendor/qcom/opensource/interfaces/customizehidl/1.0/default/
如果有如下报错的话
ERROR: Package root not specified for [email protected]
ERROR: Could not get sources for [email protected].
需要在以下目录下添加如下代码：
vendor/qcom/opensource/interfaces/Android.bp
hidl_package_root {
name:"vendor.qti.hardware.customizehidl",
path:"vendor/qcom/opensource/interfaces/customizehidl",
} 5. 在1.0/default/下生成.cpp和.h文件
在vendor/qcom/opensource/interfaces/customizehidl/1.0/default/下生成.cpp和.h文件：
hidl-gen -o $LOC -Lc++-impl -rvendor.qti.hardware:vendor/qcom/opensource/interfaces -randroid.hidl:system/libhidl/transport $PACKAGE
或者
hidl-gen -o vendor/qcom/opensource/interfaces/customizehidl/1.0/default -Lc++-impl -rvendor.qti.hardware:vendor/qcom/opensource/interfaces –randroid.hidl:system/libhidl/transport vendor.qti.hardware.customizehidl@1.0
然后会生成CustomizeHidl.cpp和CustomizeHidl.h文件。生成后需要做相关修改，修改后内容如下：
vendor/qcom/opensource/interfaces/customizehidl/1.0/default/CustomizeHidl.cpp
#include "CustomizeHidl.h"
#include <pthread.h>
#include <sched.h>
#include <map>
#include <fcntl.h>
#include <unistd.h>
namespace vendor {
namespace qti {
namespace hardware {
namespace customizehidl {
namespace V1_0 {
namespace implementation {
CustomizeHidl::CustomizeHidl() {
}
CustomizeHidl::~CustomizeHidl() {
}
Return<::vendor::qti::hardware::customizehidl::V1_0::Result> CustomizeHidl::resetOption(int32_t side) {
return ::vendor::qti::hardware::customizehidl::V1_0::Result {};
}
// Methods from ::android::hidl::base::V1_0::IBase follow.
//ICustomizeHidl* HIDL_FETCH_ICustomizeHidl(const char* /* name */) {
// return new CustomizeHidl();
//}
//
} // implementation
} // V1_0
} // customizehidl
} // hardware
} // qti
} // vendor
头文件内容如下：
vendor/qcom/opensource/interfaces/customizehidl/1.0/default/CustomizeHidl.h
#include <vendor/qti/hardware/customizehidl/1.0/ICustomizeHidl.h>
#include <hidl/MQDescriptor.h>
#include <hidl/Status.h>
#include <fstream>
#include <iostream>
namespace vendor {
namespace qti {
namespace hardware {
namespace customizehidl {
namespace V1_0 {
namespace implementation {
using namespace std;
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 CustomizeHidl : public ICustomizeHidl {
CustomizeHidl();
~CustomizeHidl();
Return<::vendor::qti::hardware::customizehidl::V1_0::Result> resetOption(int32_t side) override;
};
// FIXME: most likely delete, this is only for passthrough implementations
// extern "C" ICustomizeHidl* HIDL_FETCH_ICustomizeHidl(const char* name);
} // implementation
} //customizehidl
} // V1_0
} // hardware
} // qti
} // vendor6. 在1.0/default/下面生成Android.bp
在vendor/qcom/opensource/interfaces/customizehidl/1.0/default/下面生成Android.bp：
hidl-gen -o $LOC -Landroidbp-impl -rvendor.qti.hardware:vendor/qcom/opensource/interfaces -randroid.hidl:system/libhidl/transport $PACKAGE
生成后需要做相关修改，修改后内容如下：
cc_defaults{
name: "customizehidl_defaults",
//relative_install_path: "hw",
defaults: ["hidl_defaults"],
//根据项目需求
//vendor: true,
proprietary: true,
cflags: [
"-Wno-unused-parameter",
"-Wall",
],
shared_libs: [
"libcutils",
"liblog",
"libbase",
"libsysutils",
"libhidlbase",
"libhidltransport",
"libutils",
"[email protected]",
],
}
cc_library_shared {
name: "[email protected]",
relative_install_path: "hw",
//根据项目需求
//vendor: true,
proprietary: true,
cflags: [
"-Wno-unused-parameter",
"-Wall",
"-Wunused-variable",
"-Wunused-const-variable",
"-Wunused-variable",
],
srcs: [
"CustomizeHidl.cpp",
],
defaults: ["customizehidl_defaults"],
}
cc_binary {
name: "[email protected]",
proprietary: true,
compile_multilib: "both",
relative_install_path: "hw",
defaults: ["customizehidl_defaults"],
//rc引用
init_rc: ["vendor.qti.hardware.customizehidl-service.rc"],
//vintf_fragments引用
vintf_fragments: ["vendor.qti.hardware.customizehidl-service.xml"],
srcs: [
"service.cpp",
],
shared_libs: [
"libcutils",
"liblog",
"libbase",
"libsysutils",
"libhidlbase",
"libhidltransport",
"libutils",
"[email protected]",
],
}
7. 在1.0下生成Android.bp
在vendor/qcom/opensource/interfaces/customizehidl/1.0下生成Android.bp
source system/tools/hidl/update-makefiles-helper.sh
do_makefiles_update vendor.qti.hardware:vendor/qcom/opensource/interfaces android.hardware:hardware/interfaces android.hidl:system/libhidl/transport
生成后需要做相关修改，修改后内容如下：
hidl_interface {
name: "[email protected]",
root: "vendor.qti.hardware.customizehidl",
//根据需求进行设置
//product_specific: true,
system_ext_specific: true,
srcs: [
"types.hal",
"ICustomizeHidl.hal",
],
interfaces: [
"[email protected]",
],
gen_java: true,
}8. 在主目录android下执行如下命令生成current.txt
hidl-gen -Lhash -rvendor.qti.hardware:vendor/qcom/opensource/interfaces -randroid.hidl:system/libhidl/transport vendor.qti.hardware.customizehidl@1.0 > vendor/qcom/opensource/interfaces/customizehidl/current.txt
9. 在1.0/default/下添加vendor.qti.hardware.customizehidl-service.rc
添加如下内容
service vendor.qti.hardware.customizehidl-1-0 /vendor/bin/hw/[email protected]
class hal
user system
group system10. 在1.0/default/下添加vendor.qti.hardware.customizehidl-service.xml
<manifest version="1.0" type="device">
<hal format="hidl">
<name>vendor.qti.hardware.customizehidl</name>
<transport>hwbinder</transport>
<version>1.0</version>
<interface>
<name>ICustomizeHidl</name>
<instance>default</instance>
</interface>
</hal>
</manifest>
11. 在device/qcom/common/vendor_compatibility_matrix.xml中添加如下内容(此处我未添加，依然可以跑起来)
<hal format="hidl" optional="true">
<name>vendor.qti.hardware.customizehidl</name>
<transport>hwbinder</transport>
<version>1.0</version>
<interface>
<name>ICustomizeHidl</name>
<instance>default</instance>
</interface>
</hal>12. 在1.0/default/下添加service.cpp
如果采用Binderized方式，如下
#include <android-base/logging.h>
#include <hidl/HidlTransportSupport.h>
#include "CustomizeHidl.h"
#include <utils/Log.h>
#include <hidl/LegacySupport.h>
using namespace android;
using vendor::qti::hardware::customizehidl::V1_0::ICustomizeHidl;
using vendor::qti::hardware::customizehidl::V1_0::implementation::CustomizeHidl;
using android::hardware::configureRpcThreadpool;
using android::hardware::joinRpcThreadpool;
using android::sp;
int main(int /* argc */, char ** /* argv */) {
sp<ICustomizeHidl> service = new CustomizeHidl();
configureRpcThreadpool(1, true /*callerWillJoin*/);
if (::android::OK != service->registerAsService()) {
return -1;
}
joinRpcThreadpool();
return 0;
}
如果要采用Passthrough方式的话，则需要按如下方法写main,但同时需要将CustomizeHidl.cpp以及CustomizeHidl.h中的HIDL_FETCH_ICustomizeHidl方法放开才可以。
#include <android-base/logging.h>
#include <hidl/HidlTransportSupport.h>
#include "CustomizeHidl.h"
#include <utils/Log.h>
#include <hidl/LegacySupport.h>
using namespace android;
using vendor::qti::hardware::customizehidl::V1_0::ICustomizeHidl;
using android::hardware::configureRpcThreadpool;
using android::hardware::joinRpcThreadpool;
using android::hardware::defaultPassthroughServiceImplementation;
using android::hardware::registerPassthroughServiceImplementation;
int main() {
android::status_t status;
configureRpcThreadpool(10, false);
status = registerPassthroughServiceImplementation<ICustomizeHidl>();
LOG_ALWAYS_FATAL_IF(status != OK, "Error while registering ICustomizeHidl: %d", status);
joinRpcThreadpool();
return status;
}13. 编写测试bin程序
vendor/qcom/opensource/interfaces/customizehidl/下新增hidl_test_bin目录，并添加Android.bp
cc_binary {
name: "hidl_test_bin",
srcs: [
"hidl_test_bin.cpp",
],
shared_libs: [
"libcutils",
"libutils",
"liblog",
//以下so一定要添加，否则可能会有报错
"libbinder",
"libhidlbase",
"libbase",
"libhidltransport",
"[email protected]",
],
cflags: [
"-Werror",
"-Wno-error=deprecated-declarations",
"-Wno-unused-parameter",
"-Wall",
],
}添加hidl_test_bin.cpp文件
#define LOG_TAG "hidl_test_bin"
#include <binder/IPCThreadState.h>
#include <binder/IServiceManager.h>
#include <binder/ProcessState.h>
#include <cutils/properties.h>
#include <fcntl.h>
#include <utils/Log.h>
#include <iostream>
#include <vendor/qti/hardware/customizehidl/1.0/ICustomizeHidl.h>
#include <vendor/qti/hardware/customizehidl/1.0/types.h>
using namespace android;
using namespace std;
using vendor::qti::hardware::customizehidl::V1_0::ICustomizeHidl;
using vendor::qti::hardware::customizehidl::V1_0::Result;
using android::hardware::Return;
using android::hardware::details::return_status;
using android::hardware::Void;
sp<ICustomizeHidl> halService;
int main(int argc, char* argv[]) {
halService = ICustomizeHidl::getService();
if (halService == NULL){
cout << "get hal service failed" <<endl;
return -1;
}
cout << "get hal service scuess" <<endl;
float value = stof(argv[1]);
cout << "value is " << value <<endl;
halService->resetOption(value);
return 0;
}14. 测试
14.1 单编方法：
source build/envsetup.sh
lunch xxx
cd vendor/qcom/opensource/interfaces/customizehidl
mma(编译hidl服务相关)
cd vendor/qcom/opensource/interfaces/customizehidl/hidl_test_bin
mma(编译test bin相关)
14.2 测试方法：
1. adb pull vendor/etc/vintf/compatibility_matrix.xml
在最后增加
<hal format="hidl" optional="true">
<name>vendor.qti.hardware.customizehidl</name>
<transport>hwbinder</transport>
<version>1.0</version>
<interface>
<name>ICustomizeHidl</name>
<instance>default</instance>
</interface>
</hal>
2. 再push回去
adb root
adb remount
adb push compatibility_matrix.xml vendor/etc/vintf/compatibility_matrix.xml
3. 在out/target/product/qssi下执行
adb push ./product/lib/[email protected] product/lib/
adb push ./product/lib64/[email protected] product/lib64/
adb push ./vendor/lib/hw/[email protected] vendor/lib/hw/
adb push ./vendor/lib/[email protected] vendor/lib/
adb push ./vendor/lib64/hw/[email protected] vendor/lib64/hw/
adb push ./vendor/lib64/[email protected] vendor/lib64/
adb push ./vendor/etc/vintf/manifest/vendor.qti.hardware.customizehidl-service.xml vendor/etc/vintf/manifest
adb push ./vendor/bin/hw/[email protected] vendor/bin/hw/
adb push ./system_ext/lib/[email protected] system_ext/lib/
adb push ./system_ext/lib64/[email protected] system_ext/lib64/
adb push system/bin/hidl_test_bin system/bin(测试的bin程序)
然后执行
adb reboot
重启后
关闭selinux: adb shell setenforce 0
窗口1：起hidl服务
adb shell
cd vendor/bin/hw
./[email protected]
窗口2：起test bin程序
adb shell
hidl_test_bin 100
然后观察窗口2输出什么
如果输出如下则代表两者通信成功
get hal service scuess
value is 100
15. 可能碰到的问题
15.1 错误1
04-14 12:27:02.103 599 599 I hwservicemanager: getTransport: Cannot find entry [email protected]::ICustomizeHidl/default in either framework or device VINTF manifest.
04-14 12:27:02.104 4169 4169 E HidlServiceManagement: Service [email protected]::ICustomizeHidl/default must be in VINTF manifest in order to register/get
那就是vintf manifest相关的配置出现问题，可以检查下是否有push相应的manifest文件，接口的内容是否书写正确等。
15.2 新增目录放hal服务
如遇到新建的目录编译不出来相关hidl的out下相关文件，需要添加update-makefiles.sh文件，可以从其他hidl的目录中拷贝过来，修改其中的目录即可
set -e
if [ -z "$ANDROID_BUILD_TOP" ]; then
echo "Missing ANDROID_BUILD_TOP env variable. Run 'lunch' first."
exit 1
fisource $ANDROID_BUILD_TOP/system/tools/hidl/update-makefiles-helper.sh
do_makefiles_update \
"vendor/newname/interfaces/customizehidl"
16. 自定义Hal 服务Selinux添加
请参考我的另一篇文章