'\" te
.\" Copyright (c) 2006, Sun Microsystems, Inc.
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.TH DDI_DEV_REGSIZE 9F "Jan 16, 2006"
.SH NAME
ddi_dev_regsize \- return the size of a device's register
.SH SYNOPSIS
.nf
#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>



\fBint\fR \fBddi_dev_regsize\fR(\fBdev_info_t *\fR\fIdip\fR, \fBuint_t\fR \fIrnumber\fR, \fBoff_t *\fR\fIresultp\fR);
.fi

.SH INTERFACE LEVEL
illumos DDI specific (illumos DDI).
.SH PARAMETERS
.ne 2
.na
\fB\fIdip\fR\fR
.ad
.RS 11n
A pointer to the device's \fBdev_info\fR structure.
.RE

.sp
.ne 2
.na
\fB\fIrnumber\fR\fR
.ad
.RS 11n
The ordinal register number. Device registers are associated with a
\fBdev_info\fR and are enumerated in arbitrary sets from \fB0\fR on up. The
number of registers a device has can be determined from a call to
\fBddi_dev_nregs\fR(9F).
.RE

.sp
.ne 2
.na
\fB\fIresultp\fR\fR
.ad
.RS 11n
Pointer to an integer that holds the size, in bytes, of the described register
(if it exists).
.RE

.SH DESCRIPTION
The \fBddi_dev_regsize()\fR function returns the size, in bytes, of the device
register specified by \fIdip\fR and \fIrnumber\fR. This is useful when, for
example, one of the registers is a frame buffer with a varying size known only
to its proms.
.SH RETURN VALUES
The \fBddi_dev_regsize()\fR function returns:
.sp
.ne 2
.na
\fB\fBDDI_SUCCESS\fR\fR
.ad
.RS 15n
A successful return. The size, in bytes, of the specified register, is set in
\fIresultp\fR.
.RE

.sp
.ne 2
.na
\fB\fBDDI_FAILURE\fR\fR
.ad
.RS 15n
An invalid (nonexistent) register number was specified.
.RE

.SH CONTEXT
The \fBddi_dev_regsize()\fR function can be called from user, interrupt, or
kernel context.
.SH SEE ALSO
\fBddi_dev_nintrs\fR(9F), \fBddi_dev_nregs\fR(9F)
.sp
.LP
\fIWriting Device Drivers\fR