usbdBusMap
Purpose
Maps pinned kernel memory so that it can be bus mastered by host controller.
Syntax
#include <hcdi.h>
USBstatus usbdBusMap(pHCDI, addr, size, ppbusmap)
PHCDI pHCDI;
caddr_t addr;
int size;
PBUSMAP *ppbusmap; Parameter
| Item | Description |
|---|---|
| pHCDI | Pointer to the HCDI structure. |
| addr | Pointer to memory block aligned on a word boundary that is allocated from kernel’s pinned heap. The block must not cross a page boundary. |
| size | Size of memory block in bytes (must be less than or equal to 4096 bytes). |
| ppbusmap | Location to return address of the BUSMAP structure. |
Description
This call vector is a USBD supplied function, called by the HCD to map pinned kernel memory so that it can be read from or written to the host controller.
Execution Environment
This function can only b called from within the process environment.
Return Values
| Value | Description |
|---|---|
| USBD_SUCCESS | Success |
| All others | Failure |