'\" te
.\" Copyright (c) 2006, Sun Microsystems, Inc.
.TH ddi_iomin 9F "04 Apr 2006" "SunOS 5.11" "Kernel Functions for Drivers"
.SH NAME
ddi_iomin \- find minimum alignment and transfer size for DMA
.SH SYNOPSIS
.LP
.nf
#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>

\fBint\fR \fBddi_iomin\fR(\fBdev_info_t *\fR\fIdip\fR, \fBint\fR \fIinitial\fR, \fBint\fR \fIstreaming\fR);
.fi

.SH INTERFACE LEVEL
.sp
.LP
Solaris DDI specific (Solaris DDI). This interface is obsolete.
.SH PARAMETERS
.sp
.ne 2
.mk
.na
\fB\fIdip\fR\fR
.ad
.RS 13n
.rt  
A pointer to the device's \fBdev_info\fR structure.
.RE

.sp
.ne 2
.mk
.na
\fB\fIinitial\fR\fR
.ad
.RS 13n
.rt  
The initial minimum \fBDMA\fRtransfer size in bytes. This may be zero or an appropriate \fBdlim_minxfer\fR value for device's \fBddi_dma_lim\fR structure (see \fBddi_dma_lim_sparc\fR(9S) or \fBddi_dma_lim_x86\fR(9S)). This value must be a power of two.
.RE

.sp
.ne 2
.mk
.na
\fB\fIstreaming\fR\fR
.ad
.RS 13n
.rt  
This argument, if non-zero, indicates that the returned value should be modified to account for \fIstreaming\fR mode accesses (see \fBddi_dma_req\fR(9S) for a discussion of streaming versus non-streaming access mode).
.RE

.SH DESCRIPTION
.sp
.LP
The \fBddi_iomin()\fR function, finds out the minimum \fBDMA\fRtransfer size for the device pointed to by \fIdip\fR. 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.
.SH RETURN VALUES
.sp
.LP
The \fBddi_iomin()\fR function returns the minimum \fBDMA\fRtransfer size for the calling device, or it returns zero, which means that you cannot get there from here.
.SH CONTEXT
.sp
.LP
This function can be called from user, interrupt, or kernel context.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityObsolete
.TE

.SH SEE ALSO
.sp
.LP
\fBddi_dma_devalign\fR(9F), \fBddi_dma_setup\fR(9F), \fBddi_dma_sync\fR(9F), \fBddi_dma_lim_sparc\fR(9S), \fBddi_dma_lim_x86\fR(9S), \fBddi_dma_req\fR(9S) 
.sp
.LP
\fIWriting Device Drivers for Oracle Solaris 11.2\fR