devmap_unmap man page on SmartOS

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DEVMAP_UNMAP(9E)					      DEVMAP_UNMAP(9E)

NAME
       devmap_unmap - device mapping unmap entry point

SYNOPSIS
       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       void prefixdevmap_unmap(devmap_cookie_t dhp, void *pvtp,
	    offset_t off, size_tlen, devmap_cookie_t new_dhp1,
	    void **new_pvtp1, devmap_cookie_tnew_dhp2, void **new_pvtp2);

INTERFACE LEVEL
       Solaris DDI specific (Solaris DDI).

ARGUMENTS
       dhp
		     An opaque mapping handle that the system uses to describe
		     the mapping.

       pvtp
		     Driver private mapping data.

       off
		     User offset within the logical device memory at which the
		     unmapping begins.

       len
		     Length (in bytes) of the memory being unmapped.

       new_dhp1
		     The  opaque  mapping  handle  that	 the  system  uses  to
		     describe the new region that ends at (off - 1) . new_dhp1
		     may be  NULL.

       new_pvtp1
		     A	pointer	 to be filled in by the driver with the driver
		     private mapping data for the new region that ends at (off
		     - 1); ignored if new_dhp1 is NULL.

       new_dhp2
		     The  opaque  mapping  handle  that	 the  system  uses  to
		     describe the new region that  begins  at  (off   +	 len);
		     new_dhp2 may be  NULL.

       new_pvtp2
		     A	pointer	 to be filled in by the driver with the driver
		     private mapping data for the new region  that  begins  at
		     (off + len);  ignored if new_dhp2 is  NULL.

DESCRIPTION
       devmap_unmap()  is  called  when	 the system removes the mapping in the
       range [ off, off + len ], such as in the	 munmap(2) or  exit(2)	system
       calls. Device drivers use devmap_unmap() to free up the resources allo‐
       cated in devmap_map(9E).

       dhp is the mapping handle that uniquely identifies the  mapping.	   The
       driver  stores  the  mapping  attributes	 in the driver's private data,
       pvtp, when the mapping is created.  See devmap_map(9E) for details.

       off and len define the range to be  affected  by	 devmap_unmap().  This
       range is within the boundary of the mapping described by dhp.

       If  the	range [ off, off + len ] covers the entire mapping, the system
       passes  NULL to	new_dhp1, new_pvtp1, new_dhp2, and new_pvtp2. The sys‐
       tem  expects  device  drivers  to free all resources allocated for this
       mapping.

       If off is at the beginning of the mapping and  len does not  cover  the
       entire mapping, the system sets	NULL to new_dhp1 and to new_pvtp1. The
       system expects the drivers to allocate new driver private data for  the
       region  that  starts at off + len and to set *new_pvtp2 to point to it.
       new_dhp2 is the mapping handle of the newly mapped object.

       If off is not at the beginning of the mapping, but off + len is at  the
       end  of	the mapping the system passes  NULL to new_dhp2 and new_pvtp2.
       The system then expects the drivers to allocate new driver private data
       for  the	 region that begins at the beginning of the mapping (for exam‐
       ple, stored in pvtp) and to set *new_pvtp1 to point to it.  new_dhp1 is
       the mapping handle of the newly mapped object.

       The  drivers  should  free up the driver private data, pvtp, previously
       allocated in devmap_map(9E) before returning to the system.

EXAMPLES
       Example 1 devmap_unmap() implementation

	 static void
	 xxdevmap_unmap(devmap_cookie_t dhp, void *pvtp, offset_t off,
	     size_t len, devmap_cookie_t new_dhp1, void **new_pvtp1,
	     devmap_cookie_t new_dhp2, void **new_pvtp2)
	 {
	     struct xxpvtdata *ptmp;
	     struct xxpvtdata *p = (struct xxpvtdata *)pvtp;
	     struct xx_softc  *softc = p->softc;
	     mutex_enter(&softc->mutex);
	     /*
	      * If new_dhp1 is not NULL, create a new driver private data
	      * for the region from the beginning of old mapping to off.
	      */
	     if (new_dhp1 != NULL) {
		 ptmp = kmem_zalloc(sizeof (struct xxpvtdata), KM_SLEEP);
		 ptmp->dhp = new_dhp1;
		 ptmp->off = pvtp->off;
		 ptmp->len = off - pvtp->off;
		 *new_pvtp1 = ptmp;
	     }

	     /*
	      * If new_dhp2 is not NULL, create a new driver private data
	      * for the region from off+len to the end of the old mapping.
	      */
	     if (new_dhp2 != NULL) {
		 ptmp = kmem_zalloc(sizeof (struct xxpvtdata), KM_SLEEP);
		 ptmp->off = off + len;
		 ptmp->len = pvpt->len - (off + len - pvtp->off);
		 ptmp->dhp = new_dhp2;
		 *new_pvtp2 = ptmp;
	     }

	     /* Destroy the driver private data - Device dependent */
	     ...
	     kmem_free(pvtp, sizeof (struct xxpvtdata));
	     mutex_exit(&softc->mutex);
	 }

SEE ALSO
       exit(2), munmap(2), devmap_map(9E), devmap_callback_ctl(9S)

       Writing Device Drivers

				 Jan 21, 1997		      DEVMAP_UNMAP(9E)
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