ddi_dma_set_sbus64

- allow 64–bit transfers on SBus

Synopsis

#include <sys/ddi.h> 
#include <sys/sunddi.h> 

int ddi_dma_set_sbus64(ddi_dma_handle_t handle, uint_t burstsizes);

Interface Level

Solaris DDI specific (Solaris DDI).

Parameters

handle

The handle filled in by a call to ddi_dma_alloc_handle(9F).

burstsizes

The possible burst sizes the device's DMA engine can accept in 64–bit mode.

Description

ddi_dma_set_sbus64() informs the system that the device wishes to perform 64–bit data transfers on the SBus. The driver must first allocate a DMA handle using ddi_dma_alloc_handle(9F) with a ddi_dma_attr(9S) structure describing the DMA attributes for a 32–bit transfer mode.

burstsizes describes the possible burst sizes the device's DMA engine can accept in 64–bit mode. It may be distinct from the burst sizes for 32–bit mode set in the ddi_dma_attr(9S) structure. The system will activate 64–bit SBus transfers if the SBus supports them. Otherwise, the SBus will operate in 32–bit mode.

After DMA resources have been allocated (see ddi_dma_addr_bind_handle(9F) or ddi_dma_buf_bind_handle(9F)), the driver should retrieve the available burst sizes by calling ddi_dma_burstsizes(9F). This function will return the burst sizes in 64–bit mode if the system was able to activate 64–bit transfers. Otherwise burst sizes will be returned in 32–bit mode.

Return Values

ddi_dma_set_sbus64() returns:

DDI_SUCCESS

Successfully set the SBus to 64–bit mode.

DDI_FAILURE

64–bit mode could not be set.

Context

ddi_dma_set_sbus64() can be called from user, kernel, or interrupt context.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

attributes(5), ddi_dma_addr_bind_handle(9F), ddi_dma_alloc_handle(9F), ddi_dma_buf_bind_handle(9F), ddi_dma_burstsizes(9F), ddi_dma_attr(9S)

Notes

64–bit SBus mode is activated on a per SBus slot basis. If there are multiple SBus cards in one slot, they all must operate in 64–bit mode or they all must operate in 32–bit mode.