'\" te
.\"  Copyright (c) 1996, Sun Microsystems, Inc.  All Rights Reserved
.TH devmap_default_access 9F "14 Jan 1997" "SunOS 5.11" "Kernel Functions for Drivers"
.SH NAME
devmap_default_access \- default driver memory access function
.SH SYNOPSIS
.LP
.nf
#include <sys/ddi.h> 
#include <sys/sunddi.h>

\fBint\fR \fBdevmap_default_access\fR(\fBdevmap_cookie_t\fR \fIdhp\fR, \fBvoid *\fR\fIpvtp\fR, 
     \fBoffset_t\fR \fIoff\fR, \fBsize_t\fR \fIlen\fR, \fBuint_t\fR \fItype\fR, \fBuint_t\fR \fIrw\fR);
.fi

.SH INTERFACE LEVEL
.sp
.LP
Solaris DDI specific (Solaris DDI).
.SH PARAMETERS
.sp
.ne 2
.mk
.na
\fB\fIdhp\fR \fR
.ad
.RS 9n
.rt  
An opaque mapping handle that the system uses to describe the mapping.
.RE

.sp
.ne 2
.mk
.na
\fB\fIpvtp\fR \fR
.ad
.RS 9n
.rt  
Driver private mapping data.
.RE

.sp
.ne 2
.mk
.na
\fB\fIoff\fR \fR
.ad
.RS 9n
.rt  
User offset within the logical device memory at which the access begins.
.RE

.sp
.ne 2
.mk
.na
\fB\fIlen\fR \fR
.ad
.RS 9n
.rt  
Length (in bytes) of the memory being accessed.
.RE

.sp
.ne 2
.mk
.na
\fB\fItype\fR \fR
.ad
.RS 9n
.rt  
Type of access operation.
.RE

.sp
.ne 2
.mk
.na
\fB\fIrw\fR \fR
.ad
.RS 9n
.rt  
Type of access. 
.RE

.SH DESCRIPTION
.sp
.LP
\fBdevmap_default_access()\fR is a function providing the semantics of \fBdevmap_access\fR(9E). The drivers call \fBdevmap_default_access()\fR to handle the mappings that do not support context switching. The drivers should call \fBdevmap_do_ctxmgt\fR(9F) for the mappings that support context management.
.sp
.LP
\fBdevmap_default_access()\fR can either be called from \fBdevmap_access\fR(9E) or be used as the \fBdevmap_access\fR(9E) entry point. The arguments \fIdhp\fR,  \fIpvtp\fR,  \fIoff\fR,  \fIlen\fR, \fItype\fR,  and \fIrw\fR are provided by the \fBdevmap_access\fR(9E) entry point and must not be modified.
.SH RETURN VALUES
.sp
.ne 2
.mk
.na
\fB\fB0\fR \fR
.ad
.RS 12n
.rt  
Successful completion.
.RE

.sp
.ne 2
.mk
.na
\fB\fBNon-zero\fR\fR
.ad
.RS 12n
.rt  
An error occurred.
.RE

.SH CONTEXT
.sp
.LP
\fBdevmap_default_access()\fR must be called from the driver's \fBdevmap_access\fR(9E) entry point.
.SH EXAMPLES
.LP
\fBExample 1 \fRUsing devmap_default_access in devmap_access.
.sp
.LP
The following shows an example of using \fBdevmap_default_access()\fR in the \fBdevmap_access\fR(9E) entry point.

.sp
.in +2
.nf
\&.\|.\|.
#define OFF_DO_CTXMGT  0x40000000
#define OFF_NORMAL     0x40100000
#define CTXMGT_SIZE    0x100000
#define NORMAL_SIZE    0x100000

/*
 * Driver devmap_contextmgt(9E) callback function.
 */
static int
xx_context_mgt(devmap_cookie_t dhp, void *pvtp, offset_t offset,
    size_t length, uint_t type, uint_t rw)
{
    ......
    /*
     * see devmap_contextmgt(9E) for an example
     */
}

/*
 * Driver devmap_access(9E) entry point
 */
static int
xxdevmap_access(devmap_cookie_t dhp, void *pvtp, offset_t off,
    size_t len, uint_t type, uint_t rw)
{
    offset_t diff;
    int err;

    /*
     * check if off is within the range that supports
     * context management.
     */
    if ((diff = off - OFF_DO_CTXMG) >= 0 && diff < CTXMGT_SIZE) {
        /*
         * calculates the length for context switching
         */
        if ((len + off) > (OFF_DO_CTXMGT + CTXMGT_SIZE))
            return (-1);
        /*
         * perform context switching
         */
        err = devmap_do_ctxmgt(dhp, pvtp, off, len, type,
            rw,  xx_context_mgt);
    /*
     * check if off is within the range that does normal
     * memory mapping.
     */
    } else if ((diff = off - OFF_NORMAL) >= 0 && diff < NORMAL_SIZE) {
        if ((len + off) > (OFF_NORMAL + NORMAL_SIZE))
            return (-1);
        err = devmap_default_access(dhp, pvtp, off, len, type, rw);
    } else
        return (-1);

    return (err);
}
.fi
.in -2

.SH SEE ALSO
.sp
.LP
\fBdevmap_access\fR(9E), \fBdevmap_do_ctxmgt\fR(9F), \fBdevmap_callback_ctl\fR(9S) 
.sp
.LP
\fIWriting Device Drivers for Oracle Solaris 11.2\fR