SVR5

dma_prog(D3)

dma_prog -- program a DMA operation for a subsequent hardware request

Synopsis

   #include <sys/types.h>
   #include <sys/dma.h>
   #include <sys/ddi.h>
   
   int dma_prog(struct dma_cb *dmacbptr, int chan, uchar_t mode);

Description

dma_prog programs the ISA, EISA, or MCA DMA channel chan for the operation specified by the DMA command block whose address is given by dmacbptr.

Arguments

dmacbptr: Pointer to the DMA command block that specifies the DMA operation.
chan: DMA channel over which the operation is to take place.
mode: Specifies whether the caller is willing to sleep waiting to allocate desired DMA channel.

Return values

dma_prog returns the value TRUE upon successful completion and returns the value FALSE otherwise.

Usage

dma_prog does not initiate the DMA transfer. Instead, the transfer will be initiated by a subsequent request from hardware. The hardware request will be recognized only if the channel has been enabled via dma_enable(D3) following the call to dma_prog.

In order to program the operation, dma_prog requires exclusive use of the specified DMA channel. The caller may specify, via the mode argument, whether or not dma_prog should sleep waiting for a busy channel to become available. If the specified channel is in use, and mode is set to DMA_SLEEP, then dma_prog will sleep until the channel becomes available for its use. Otherwise, if DMA_NOSLEEP is specified and the requested channel is not immediately available, dma_prog will not program the channel, but will simply return a value of FALSE.

Context and synchronization

If mode is set to DMA_NOSLEEP, non-blockable, initialization, or interrupt context.

If mode is set to DMA_SLEEP, user context.

Hardware applicability

PC-AT compatible platforms with ISA, EISA, or MCA buses

Version applicability

ddi: 1, 2, 3, 4, 5, 5mp, 6, 6mp, 7, 7mp, 7.1, 7.1mp, 8, 8mp

Future directions

This interface is expected to be replaced or modified in a future release.

References

dma_disable(D3), dma_enable(D3), dma_cb(D4)

``DMA'' in HDK Technical Reference