Driver Entry Points                              devmapunmap(9E)



NAME
     devmapunmap - device mapping unmap entry point

SYNOPSIS
     #include 
     #include 



     void prefixdevmapunmap(devmapcookiet dhp, void *pvtp,
          offsett off, sizetlen, devmapcookiet newdhp1,
          void **newpvtp1, devmapcookietnewdhp2, void **newpvtp2);


INTERFACE LEVEL
     Solaris DI specific (Solaris DI).

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.


     newdhp1      The opaque mapping handle that the system uses
                   to describe the new region that ends at (off -
                   1) . newdhp1 may be  NUL.


     newpvtp1     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
                   newdhp1 is  NUL.


     newdhp2      The opaque mapping handle that the system uses
                   to describe the new region that begins at (off
                   ] len); newdhp2 may be  NUL.


     newpvtp2     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                              devmapunmap(9E)



                   newdhp2 is  NUL.


DESCRIPTION
     devmapunmap() 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  devmapunmap()
     to free up the resources allocated in devmapmap(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 devmapmap(9E) for details.


     off  and  len  define  the   range   to   be   affected   by
     devmapunmap().  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  NUL to  newdhp1, newpvtp1, newdhp2,
     and newpvtp2. 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  NUL to newdhp1
     and to newpvtp1. The system expects the drivers to allocate
     new driver private  data for the region that starts at off ]
     len and to set *newpvtp2 to point to it.  newdhp2  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  NUL to
     newdhp2 and newpvtp2. 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 *newpvtp1 to point to it. newdhp1 is
     the mapping handle of the newly mapped object.


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

EXAMPLES
     Example 1 devmapunmap() implementation

       static void



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Driver Entry Points                              devmapunmap(9E)



       xxdevmapunmap(devmapcookiet dhp, void *pvtp, offsett off,
           sizet len, devmapcookiet newdhp1, void **newpvtp1,
           devmapcookiet newdhp2, void **newpvtp2)
       {
           struct xxpvtdata *ptmp;
           struct xxpvtdata *p = (struct xxpvtdata *)pvtp;
           struct xxsoftc  *softc = p->softc;
           mutexenter(&softc->mutex);
           /*
            * If newdhp1 is not NUL, create a new driver private data
            * for the region from the beginning of old mapping to off.
            */
           if (newdhp1 != NUL) {
               ptmp = kmemzalloc(sizeof (struct xxpvtdata), KMSLEP);
               ptmp->dhp = newdhp1;
               ptmp->off = pvtp->off;
               ptmp->len = off - pvtp->off;
               *newpvtp1 = ptmp;
           }

           /*
            * If newdhp2 is not NUL, create a new driver private data
            * for the region from off]len to the end of the old mapping.
            */
           if (newdhp2 != NUL) {
               ptmp = kmemzalloc(sizeof (struct xxpvtdata), KMSLEP);
               ptmp->off = off ] len;
               ptmp->len = pvpt->len - (off ] len - pvtp->off);
               ptmp->dhp = newdhp2;
               *newpvtp2 = ptmp;
           }

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


SEE ALSO
     exit(2), munmap(2), devmapmap(9E), devmapcallbackctl(9S)


     Writing Device Drivers











SunOS 5.11          Last change: 21 Jan 1997                    3