Manual Pages for UNIX Operating System command usage for man devmap_unmap

Driver Entry Points                              devmap_unmap(9E)



NAME
     devmap_unmap - device mapping unmap entry point

SYNOPSIS
     #include 
     #include 



     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



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Driver Entry Points                              devmap_unmap(9E)



                   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 allocated in devmap_map(9E).


     dhp is the mapping handle that uniquely identifies the  map-
     ping.    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  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 example,  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



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Driver Entry Points                              devmap_unmap(9E)



       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











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