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| Kernel Functions for Drivers | ddi_iomin(9F) |
| | ddi_iomin - find minimum alignment and transfer size for DMA |
SYNOPSIS
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#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
int ddi_iomin(dev_info_t *dip, int initial, int streaming); |
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Solaris DDI specific (Solaris DDI).
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dip
- A pointer to the device's dev_info structure.
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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_IA(9s)).
This value must be a power of two.
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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).
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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.
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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.
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This function can be called from user or interrupt context.
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