ddi_iomin(9F) Kernel Functions for Drivers ddi_iomin(9F)
NAME
ddi_iomin - find minimum alignment and transfer size for DMA
SYNOPSIS
#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
int ddi_iomin(dev_info_t *dip, int initial, int streaming);
INTERFACE LEVEL
Solaris DDI specific (Solaris DDI).
PARAMETERS
dip A pointer to the device's dev_info structure.
initial The initial minimum DMA transfer size in bytes. This may be zero or an appropriate dlim_minxfer value for device's
ddi_dma_lim structure (see ddi_dma_lim_sparc(9S) or ddi_dma_lim_x86(9S)). This value must be a power of two.
streaming This argument, if non-zero, indicates that the returned value should be modified to account for streaming mode accesses
(see ddi_dma_req(9S) for a discussion of streaming versus non-streaming access mode).
DESCRIPTION
ddi_iomin(), finds out the minimum DMA transfer size for the device pointed to by dip. This provides a mechanism by which a driver can
determine the effects of underlying caches as well as intervening bus adapters on the granularity of a DMA transfer.
RETURN VALUES
ddi_iomin() returns the minimum DMA transfer size for the calling device, or it returns zero, which means that you cannot get there from
here.
CONTEXT
This function can be called from user or interrupt context.
SEE ALSO
ddi_dma_devalign(9F), ddi_dma_setup(9F), ddi_dma_sync(9F), ddi_dma_lim_sparc(9S), ddi_dma_lim_x86(9S), ddi_dma_req(9S)
Writing Device Drivers
SunOS 5.10 1 Feb 1994 ddi_iomin(9F)