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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] .TH SEGMAP 9E "Jan 14, 1997" .SH NAME segmap \- map device memory into user space .SH SYNOPSIS .LP .nf #include #include #include #include #include #include \fBint prefix\fR\fBsegmap\fR(\fBdev_t\fR \fIdev\fR, \fBoff_t\fR \fIoff\fR, \fBstruct as *\fR\fIasp\fR, \fBcaddr_t *\fR\fIaddrp\fR, \fBoff_t\fR \fIlen\fR, \fBunsigned int\fR \fIprot\fR, \fBunsigned int\fR \fImaxprot\fR, \fBunsigned int\fR \fIflags\fR, \fBcred_t *\fR\fIcred_p\fR); .fi .SH INTERFACE LEVEL .sp .LP Architecture independent level 2 (DKI only). .SH ARGUMENTS .sp .ne 2 .na \fB\fIdev\fR \fR .ad .RS 12n Device whose memory is to be mapped. .RE .sp .ne 2 .na \fB\fIoff\fR \fR .ad .RS 12n Offset within device memory at which mapping begins. .RE .sp .ne 2 .na \fB\fIasp\fR \fR .ad .RS 12n Pointer to the address space into which the device memory should be mapped. .RE .sp .ne 2 .na \fB\fIaddrp\fR \fR .ad .RS 12n Pointer to the address in the address space to which the device memory should be mapped. .RE .sp .ne 2 .na \fB\fIlen\fR \fR .ad .RS 12n Length (in bytes) of the memory to be mapped. .RE .sp .ne 2 .na \fB\fIprot\fR \fR .ad .RS 12n A bit field that specifies the protections. Possible settings are: .sp .ne 2 .na \fB\fBPROT_READ\fR \fR .ad .RS 15n Read access is desired. .RE .sp .ne 2 .na \fB\fBPROT_WRITE\fR \fR .ad .RS 15n Write access is desired. .RE .sp .ne 2 .na \fB\fBPROT_EXEC\fR \fR .ad .RS 15n Execute access is desired. .RE .sp .ne 2 .na \fB\fBPROT_USER\fR \fR .ad .RS 15n User-level access is desired (the mapping is being done as a result of a \fBmmap\fR(2) system call). .RE .sp .ne 2 .na \fB\fBPROT_ALL\fR \fR .ad .RS 15n All access is desired. .RE .RE .sp .ne 2 .na \fB\fImaxprot\fR \fR .ad .RS 12n Maximum protection flag possible for attempted mapping; the \fBPROT_WRITE\fR bit may be masked out if the user opened the special file read-only. .RE .sp .ne 2 .na \fB\fIflags\fR \fR .ad .RS 12n Flags indicating type of mapping. Possible values are (other bits may be set): .sp .ne 2 .na \fB\fBMAP_SHARED\fR \fR .ad .RS 16n Changes should be shared. .RE .sp .ne 2 .na \fB\fBMAP_PRIVATE\fR \fR .ad .RS 16n Changes are private. .RE .RE .sp .ne 2 .na \fB\fIcred_p\fR \fR .ad .RS 12n Pointer to the user credentials structure. .RE .SH DESCRIPTION .sp .LP The \fBsegmap()\fR entry point is an optional routine for character drivers that support memory mapping. The \fBmmap\fR(2) system call, when applied to a character special file, allows device memory to be mapped into user space for direct access by the user application. .sp .LP Typically, a character driver that needs to support the \fBmmap\fR(2) system call supplies either an \fBdevmap\fR(9E) entry point, or both an \fBdevmap\fR(9E) and a \fBsegmap()\fR entry point routine (see the \fBdevmap\fR(9E) reference page). If no \fBsegmap()\fR entry point is provided for the driver, \fBdevmap_setup\fR(9F) is used as a default. .sp .LP A driver for a memory-mapped device would provide a \fBsegmap()\fR entry point if it: .RS +4 .TP .ie t \(bu .el o needs to maintain a separate context for each user mapping. See \fBdevmap_setup\fR(9F) for details. .RE .RS +4 .TP .ie t \(bu .el o needs to assign device access attributes to the user mapping. .RE .sp .LP The responsibilities of a \fBsegmap()\fR entry point are: .RS +4 .TP .ie t \(bu .el o Verify that the range, defined by \fIoffset\fR and \fIlen\fR, to be mapped is valid for the device. Typically, this task is performed by calling the \fBdevmap\fR(9E) entry point. Note that if you are using \fBddi_devmap_segmap\fR(9F) or \fBdevmap_setup\fR(9F) to set up the mapping, it will call your \fBdevmap\fR(9E) entry point for you to validate the range to be mapped. .RE .RS +4 .TP .ie t \(bu .el o Assign device access attributes to the mapping. See \fBddi_devmap_segmap\fR(9F), and \fBddi_device_acc_attr\fR(9S) for details. .RE .RS +4 .TP .ie t \(bu .el o Set up device contexts for the user mapping if your device requires context switching. See \fBdevmap_setup\fR(9F) for details. .RE .RS +4 .TP .ie t \(bu .el o Perform the mapping with \fBddi_devmap_segmap\fR(9F), or \fBdevmap_setup\fR(9F) and return the status if it fails. .RE .SH RETURN VALUES .sp .LP The \fBsegmap()\fR routine should return \fB0\fR if the driver is successful in performing the memory map of its device address space into the specified address space. .sp .LP The \fBsegmap()\fR must return an error number on failure. For example, valid error numbers would be \fBENXIO\fR if the offset/length pair specified exceeds the limits of the device memory, or \fBEINVAL\fR if the driver detects an invalid type of mapping attempted. .sp .LP If one of the mapping routines \fBddi_devmap_segmap()\fR or \fBdevmap_setup()\fRfails, you must return the error number returned by the respective routine. .SH SEE ALSO .sp .LP \fBmmap\fR(2), \fBdevmap\fR(9E), \fBdevmap_setup\fR(9F), \fBddi_devmap_segmap\fR(9F), \fBddi_device_acc_attr\fR(9S) .sp .LP \fIWriting Device Drivers\fR