ddk_api.h
Overview
Declares the BASE DDK APIs used by the USB host to access USB devices.
File to include: <ddk/ddk_api.h>
Library: libddk_base.z.so
System capability: SystemCapability.Driver.DDK.Extension
Since: 12
Related module: Ddk
Summary
Function
| Name | Description |
|---|---|
| DDK_RetCode OH_DDK_CreateAshmem(const uint8_t *name, uint32_t size, DDK_Ashmem **ashmem) | Creates an Ashmem object. To prevent resource leakage, call OH_DDK_DestroyAshmem to destroy the Ashmem object when it is no longer needed. |
| DDK_RetCode OH_DDK_MapAshmem(DDK_Ashmem *ashmem, const uint8_t ashmemMapType) | Maps the created Ashmem object to the user space. Call OH_DDK_UnmapAshmem to unmap the Ashmem object when it is no longer needed. |
| DDK_RetCode OH_DDK_UnmapAshmem(DDK_Ashmem *ashmem) | Unmaps an Ashmem object. |
| DDK_RetCode OH_DDK_DestroyAshmem(DDK_Ashmem *ashmem) | Destroys an Ashmem object. |
Function Description
OH_DDK_CreateAshmem()
DDK_RetCode OH_DDK_CreateAshmem(const uint8_t *name, uint32_t size, DDK_Ashmem **ashmem)
Description
Creates an Ashmem object. To prevent resource leakage, call OH_DDK_DestroyAshmem to destroy the Ashmem object when it is no longer needed.
Since: 12
Parameters
| Name | Description |
|---|---|
| const uint8_t *name | Pointer to the name of the Ashmem object. |
| uint32_t size | Buffer size of the Ashmem object. |
| DDK_Ashmem **ashmem | Pointer to the Ashmem object. |
Returns
| Type | Description |
|---|---|
| DDK_RetCode | DDK_SUCCESS: The API call is successful. DDK_INVALID_PARAMETER: The input name is a null pointer, the value of size is 0, or the input ashmem is a null pointer. DDK_FAILURE: The attempt to create an Ashmem object or the DDK_Ashmem structure fails. |
OH_DDK_MapAshmem()
DDK_RetCode OH_DDK_MapAshmem(DDK_Ashmem *ashmem, const uint8_t ashmemMapType)
Description
Maps the created Ashmem object to the user space. Call OH_DDK_UnmapAshmem to unmap the Ashmem object when it is no longer needed.
Since: 12
Parameters
| Name | Description |
|---|---|
| DDK_Ashmem *ashmem | Pointer to the Ashmem object. |
| const uint8_t ashmemMapType | Mapping type for the Ashmem object. |
Returns
| Type | Description |
|---|---|
| DDK_RetCode | DDK_SUCCESS: The API call is successful. DDK_NULL_PTR: The input ashmem is a null pointer. DDK_FAILURE: The file descriptor of the Ashmem object is invalid. DDK_INVALID_OPERATION: The attempt to call MapAshmem fails. |
OH_DDK_UnmapAshmem()
DDK_RetCode OH_DDK_UnmapAshmem(DDK_Ashmem *ashmem)
Description
Unmaps an Ashmem object.
Since: 12
Parameters
| Name | Description |
|---|---|
| DDK_Ashmem *ashmem | Pointer to the Ashmem object. |
Returns
| Type | Description |
|---|---|
| DDK_RetCode | DDK_SUCCESS: The API call is successful. DDK_NULL_PTR: The input ashmem is a null pointer. DDK_FAILURE: The file descriptor of the Ashmem object is invalid. |
OH_DDK_DestroyAshmem()
DDK_RetCode OH_DDK_DestroyAshmem(DDK_Ashmem *ashmem)
Description
Destroys an Ashmem object.
Since: 12
Parameters
| Name | Description |
|---|---|
| DDK_Ashmem *ashmem | Pointer to the Ashmem object. |
Returns
| Type | Description |
|---|---|
| DDK_RetCode | DDK_SUCCESS: The API call is successful. DDK_NULL_PTR: The input ashmem is a null pointer. DDK_FAILURE: The file descriptor of the Ashmem object is invalid. |