@@ -16,7 +16,7 @@ The figure below shows the HDF driver model.
The HDF-based driver development involves driver implementation and configuration. The procedure is as follows:
1. Implement a driver.
1. Implement a driver.<br/>
Write the driver code and register the driver entry with the HDF.
- Writing the driver service code
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@@ -68,11 +68,11 @@ The HDF-based driver development involves driver implementation and configuratio
HDF_INIT(g_sampleDriverEntry);
```
2. Build the driver.
- LiteOS
2. Build the driver.<br/>
- LiteOS<br/>
Modify **makefile** and **BUILD.gn**.
- **makefile**:
- **makefile**:<br/>
Use the **makefile** template provided by the HDF to compile the driver code.
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@@ -93,7 +93,7 @@ The HDF-based driver development involves driver implementation and configuratio
LIB_SUBDIRS += # Directory in which the driver code makefile is located.
```
- **BUILD.gn**:
- **BUILD.gn**:<br/>
Add **BUILD.gn**. The content of **BUILD.gn** is as follows:
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@@ -126,7 +126,7 @@ The HDF-based driver development involves driver implementation and configuratio
]
}
```
- Linux
- Linux<br/>
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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@@ -148,12 +148,12 @@ The HDF-based driver development involves driver implementation and configuratio
obj-y += xxx.o
```
3. Configure the driver.
3. Configure the driver.<br/>
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
- (Mandatory) Setting the driver device description<br/>
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:
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@@ -208,7 +208,7 @@ The HDF-based driver development involves driver implementation and configuratio
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).
The following is an example of the driver private configuration:
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@@ -255,5 +255,5 @@ The HDF-based driver development involves driver implementation and configuratio
>
> 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 Message Mechanism Management](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** fields (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.
