Cleans up after a direct memory access (DMA) transfer.
#include <sys/types.h> #include <sys/errno.h> #include <sys/dma.h> #include <sys/xmem.h>
int d_complete (channel_id, flags, baddr, count, dp, daddr) int channel_id; int flags; caddr_t baddr; size_t count; struct xmem *dp; caddr_t daddr;
| channel_id | Specifies the DMA channel identifier returned by the d_init service. |
| flags | Describes the DMA transfer. The /usr/include/dma.h file describes these flags. |
| baddr | Designates the address of the memory buffer. |
| count | Specifies the length of the transfer in bytes. |
| dp | Specifies the address of the cross-memory descriptor. |
| daddr | Designates the address used to program the DMA master. A value of null is specified for DMA slaves. |
The d_complete kernel service completes the processing of a DMA transfer. It also indicates any DMA error detected by the system hardware. The d_complete service must be called after each DMA transfer.
The d_complete service performs machine-dependent processing, which entails:
Note: When calling the d_master service several times for one or more of the same pages of memory, the corresponding number of d_complete calls must be made to reveal successfully the page or pages involved in the DMA transfers. Pages are not hidden from the processor during the DMA mapping if the DMA_WRITE_ONLY flag is specified on the call to the d_master service.
"Understanding Direct Memory Access (DMA) Transfers" in AIX Kernel Extensions and Device Support Programming Concepts further describes DMA transfers.
The d_complete kernel service can be called from either the process or interrupt environment.
| DMA_SUCC | Indicates a successful completion. |
| DMA_INVALID | Indicates an operation that is not valid. A load or store that was not valid was performed to the I/O bus. |
| DMA_LIMIT | Indicates a limit check. A load or store to the I/O bus occurred that was not sufficiently authorized to access the I/O bus address. |
| DMA_NO_RESPONSE | Indicates no response. No device responded to the I/O bus access. |
| DMA_CONFLICT | Indicates an address conflict. A daddr parameter was specified to the d_master service for a system memory transfer, where this transfer conflicts with the bus memory address of an I/O bus device. |
| DMA_AUTHORITY | Indicates an authority error. A protection exception occurred while accessing an I/O bus memory address. |
| DMA_PAGE_FAULT | Indicates a page fault. A reference was made to a page not currently located in system memory. |
| DMA_BAD_ADDR | Indicates an address that is not valid. A bus address that is not valid or was unsupported was used. A daddr parameter that was not valid was specified to the d_master service. |
| DMA_CHECK | Indicates a channel check. A channel check was generated during the bus cycle. This typically occurs when a device detects a data parity error. |
| DMA_DATA | Indicates a system-detected data parity error. |
| DMA_ADDRESS | Indicates a system-detected address parity error. |
| DMA_EXTRA | Indicates an extra request. This typically occurs when the count parameter was specified incorrectly to the d_slave service. |
| DMA_SYSTEM | Indicates a system error. The system detected an internal error in system hardware. This is typically a parity error on an internal bus or register. |
The d_complete kernel service is part of Base Operating System (BOS) Runtime.
The d_init kernel service, d_master kernel service, d_slave kernel service.
I/O Kernel Services and Understanding Direct Memory Access (DMA) Transfers in AIX Version 4.3 Kernel Extensions and Device Support Programming Concepts.