@@ -51,7 +51,8 @@ The HDF-based driver development involves driver implementation and configuratio
return;
}
```
- Registering the driver entry with the HDF
- Register the driver entry with the HDF.
```
// Define a driver entry object. It must be a global variable of the HdfDriverEntry type (defined in hdf_device_desc.h).
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...
@@ -71,19 +72,19 @@ The HDF-based driver development involves driver implementation and configuratio
- LiteOS
Modify **makefile** and **BUILD.gn**.
Modify **Makefile** and **BUILD.gn** files.
-**Makefile**:<br/>
- **Makefile**:
Use the **makefile** template provided by the HDF to compile the driver code.
Use the **Makefile** template provided by the HDF to compile the driver code.
```
include $(LITEOSTOPDIR)/../../drivers/adapter/khdf/liteos/lite.mk # Import the content predefined by the HDF. This operation is mandatory.
include $(LITEOSTOPDIR)/../../drivers/adapter/khdf/liteos/lite.mk # (Mandatory) Import the HDF predefined content.
MODULE_NAME := # File to be generated.
LOCAL_INCLUDE: = # Directory of the driver header files.
LOCAL_SRCS : = # Source code file of the driver.
LOCAL_CFLAGS : = # Custom compilation options.
LOCAL_SRCS : = # Source code files of the driver.
LOCAL_CFLAGS : = # Custom build options.
include $(HDF_DRIVER) # Import the Makefile template to complete the build.
```
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...
@@ -111,9 +112,9 @@ The HDF-based driver development involves driver implementation and configuratio
]
public_configs = [ ":public" ] # Head file configuration of the dependencies.
}
config("public") {# Define the head file configuration of the dependencies.
config("public") { # Define the head file configuration of the dependencies.
include_dirs = [
"xxx/xxx/xxx", # Directory of the dependency header files.
"xxx/xxx/xxx", # Directory of dependency header files.
]
}
```
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...
@@ -129,7 +130,6 @@ The HDF-based driver development involves driver implementation and configuratio
]
}
```
- Linux
To define the driver control macro, add the **Kconfig** file to the driver directory **xxx** and add the path of the **Kconfig** file to **drivers/adapter/khdf/linux/Kconfig**.
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...
@@ -146,22 +146,24 @@ The HDF-based driver development involves driver implementation and configuratio
obj-$(CONFIG_DRIVERS_HDF) += xxx/
```
Add a **Makefile** to the driver directory **xxx** and add code compiling rules of the driver to the file.
Add a **Makefile** to the driver directory **xxx** and add code compiling rules of the driver to the **Makefile** file.
```
obj-y += xxx.o
```
3. Configure the driver.<br/>
3. Configure the driver.
The HDF Configuration Source (HCS) contains the source code of HDF configuration. For details about the HCS, see [Configuration Management](../driver/driver-hdf-manage.md).
The driver configuration consists of the driver device description defined by the HDF and the private driver configuration.
- (Mandatory) Setting the driver device description<br/>
- (Mandatory) Set driver device information.
The HDF loads a driver based on the driver device description defined by the HDF. Therefore, the driver device description must be added to the **device_info.hcs** file defined by the HDF.
The HDF loads a driver based on the driver device description defined by the HDF. Therefore, the driver device description must be added to the **device_info.hcs** file defined by the HDF. The following is an example:
The following is an example:
```
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...
@@ -171,9 +173,9 @@ The HDF-based driver development involves driver implementation and configuratio
template host { // Host template. If a node (for example, sample_host) uses the default values in this template, the node fields can be omitted.
hostName = "";
priority = 100;
uid = ""; // User ID (UID) of a user-mode process. It is left empty by default. If you do not set the value, this parameter will be set to the value of hostName, which indicates a common user.
gid = ""; // Group ID (GID) of a user-mode process. It is left empty by default. If you do not set the value, this parameter will be set to the value of hostName, which indicates a common user group.
caps = [""]]; // Linux capabilities of a user-mode process. It is left empty by default. Set this parameter based on service requirements.
uid = ""; // User ID (UID) of the user-mode process. It is left empty by default. If you do not set the value, this parameter will be set to the value of hostName, which indicates a common user.
gid = ""; // Group ID (GID) of the user-mode process. It is left empty by default. If you do not set the value, this parameter will be set to the value of hostName, which indicates a common user group.
caps = [""]]; // Linux capabilities of the user-mode process. It is left empty by default. Set this parameter based on service requirements.
template device {
template deviceNode {
policy = 0;
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@@ -194,7 +196,7 @@ The HDF-based driver development involves driver implementation and configuratio
device0 :: deviceNode { // DeviceNode of the sample driver.
policy = 1; // Policy for publishing the driver service. For details, see Driver Service Management.
priority = 100; // Driver startup priority (0-200). A smaller value indicates a higher priority. The default value 100 is recommended. The drivers with the same priority start based on the time when the priority was configured. The driver configured first starts first.
preload = 0; // The loading mode of the driver is on-demand loading. For details, see "NOTE" at the end of this document.
preload = 0; // The driver is loaded on demand. For details, see "NOTE" at the end of this document.
permission = 0664; // Permission for the driver to create a device node.
moduleName = "sample_driver"; // Driver name. The value of this field must be the same as that of moduleName in the HdfDriverEntry structure.
serviceName = "sample_service"; // Name of the service published by the driver. The service name must be unique.
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@@ -205,19 +207,21 @@ The HDF-based driver development involves driver implementation and configuratio
- **uid**, **gid**, and **caps** are startup parameters for user-mode drivers only.
- According to the principle of least privilege for processes, **uid** and **gid** do not need to be configured for service modules. In the preceding example, **uid** and **gid** are left empty (granted with the common user rights) for sample_host.
- If you need to set **uid** and **gid** to **system** or **root** due to service requirements, contact security experts for review.
> - **uid**, **gid**, and **caps** are startup parameters for user-mode drivers only.
>
> - According to the principle of least privilege for processes, **uid** and **gid** do not need to be configured for service modules. In the preceding example, **uid** and **gid** are left empty (granted with the common user rights) for sample_host.
>
> - If you need to set **uid** and **gid** to **system** or **root** due to service requirements, contact security experts for review.
>
> - The process UIDs are configured in **base/startup/init_lite/services/etc/passwd**, and the process GIDs are configured in **base/startup/init_lite/services/etc/group**. For details, see [Adding a System Service User Group]( https://gitee.com/openharmony/startup_init_lite/wikis).
>
> - If CAP_DAC_OVERRIDE needs to be configured for a service module, enter **caps = ["DAC_OVERRIDE"]** instead of **caps = ["CAP_DAC_OVERRIDE"]**.
- The process UIDs are configured in **base/startup/init_lite/services/etc/passwd**, and the process GIDs are configured in **base/startup/init_lite/services/etc/group**. For details, see [Adding a System Service User Group]( https://gitee.com/openharmony/startup_init_lite/wikis).
- If CAP_DAC_OVERRIDE needs to be configured for a service module, enter **caps = ["DAC_OVERRIDE"]** instead of **caps = ["CAP_DAC_OVERRIDE"]**.
If the driver has private configuration, add a driver configuration file to set default driver configuration. When loading the driver, the HDF obtains and saves the driver private information in **property** of **HdfDeviceObject**, and passes the information to the driver using **Bind()** and **Init()** (see step 1).
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@@ -243,7 +247,11 @@ The HDF-based driver development involves driver implementation and configuratio
@@ -257,11 +265,12 @@ The HDF-based driver development involves driver implementation and configuratio
> } DevicePreload;
> ```
>
> If **preload** in the configuration file is set to **0 (DEVICE_PRELOAD_ENABLE)**, the driver is loaded by default during the system boot process.
> - If **preload** in the configuration file is set to **0** (**DEVICE_PRELOAD_ENABLE**), the driver is loaded by default during the system boot process.
>
> - If **preload** is set to **1** (**DEVICE_PRELOAD_ENABLE_STEP2**), the driver is loaded after a quick start is complete. If the system does not support quick start, the value **1** has the same meaning as **DEVICE_PRELOAD_ENABLE**.
>
> If **preload** is set to **1 (DEVICE_PRELOAD_ENABLE_STEP2)**, the driver is loaded after a quick start is complete. If the system does not support quick start, the value **1** has the same meaning as **DEVICE_PRELOAD_ENABLE**.
> - If **preload** is set to **2** (**DEVICE_PRELOAD_DISABLE**), the driver service is dynamically loaded. When a user-mode process requests the driver service, the HDF attempts to dynamically load the driver if the driver service is not available. > For more details, see [Driver Messaging Mechanism](../driver/driver-hdf-message-management.md).
>
> If **preload** is set to **2 (DEVICE_PRELOAD_DISABLE)** , the driver is dynamically loaded instead of being loaded during the system boot process. When a user-mode process requests the driver service, the HDF attempts to dynamically load the driver if the driver service does not exist. For more details, see [Driver Messaging Mechanism](driver-hdf-message-management.md).
> - Sequential loading (**preload** set to **0 (DEVICE_PRELOAD_ENABLE)**)
>
> - Sequential loading (**preload** set to **0 (DEVICE_PRELOAD_ENABLE)**)<br/>
> In the configuration file, the **priority** field (value range: 0 to 200) determines the loading sequence of a host and a driver. For drivers in different hosts, a smaller host priority value indicates a higher driver loading priority; for drivers in the same host, a smaller driver priority value indicates a higher driver loading priority.
> In the configuration file, the **priority** field (ranging from 0 to 200) determines the loading sequence of a host and a driver. For drivers in different hosts, a smaller host priority value indicates a higher driver loading priority; for drivers in the same host, a smaller driver priority value indicates a higher driver loading priority.
Driver services are objects of capabilities provided by HDF driver devices to external systems and are managed by the HDF in a unified manner. Driver service management involves publishing and obtaining driver services.
The HDF uses the **policy** field in the configuration file to define policies for drivers to publish services externally. The values this field are as follows:
The HDF uses the **policy** field in the configuration file to define policies for a driver to provide services externally. The values this field are as follows:
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@@ -39,26 +39,26 @@ The table below describes the APIs for driver service management.
| API| Description|
| -------- | -------- |
| int32_t (\*Bind)(struct HdfDeviceObject \*deviceObject); | Binds a service API to the HDF. You need to implement the **Bind()** function.|
| const struct HdfObject \*DevSvcManagerClntGetService(const char \*svcName); | Obtains a driver service.|
| int HdfDeviceSubscribeService(<br>struct HdfDeviceObject \*deviceObject, const char \*serviceName, struct SubscriberCallback callback); | Subscribes to a driver service.|
| int32_t (\*Bind)(struct HdfDeviceObject \*deviceObject) | Binds a service API to the HDF. You need to implement the **Bind()** function.|
@@ -106,10 +108,14 @@ The development procedure is as follows:
}
sampleService->ServiceA();
sampleService->ServiceB(5);
```
```
- Using the subscription mechanism
If the kernel mode is unaware of the time for loading drivers on the same host, use the subscription mechanism provided by the HDF to subscribe to the drivers. After the drivers are loaded, the HDF sends the driver services to the subscriber. The implementation is as follows:
If the kernel mode is unaware of the time for loading drivers on the same host, use the subscription mechanism provided by the HDF to subscribe to the drivers. After the drivers are loaded, the HDF publishes the driver services to the subscriber.
The implementation is as follows:
```
// Callback invoked to return the driver services after the subscribed driver is loaded.
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@@ -141,3 +147,6 @@ The development procedure is as follows:
