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devmap_unmap(9e)

devmap_unmap(9E)              Driver Entry Points             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 system
       expects  device  drivers  to free all resources allocated for this map‐
       ping.


       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 in Oracle Solaris 11.4



Oracle Solaris 11.4               21 Jan 1997                 devmap_unmap(9E)
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