arch/i386-pc/exec/cachepostdma.c

   1 /*
   2     Copyright © 1995-2008, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: CachePostDMA() - Do what is necessary for DMA.
   6     Lang: english
   7 */
   8
   9 #define DEBUG 0
  10
  11 #include <aros/debug.h>
  12 #include <exec/types.h>
  13 #include <exec/execbase.h>
  14 #include <aros/libcall.h>
  15
  16 /*****************************************************************************
  17
  18     NAME */
  19 #include <proto/exec.h>
  20
  21         AROS_LH3(void, CachePostDMA,
  22
  23 /*  SYNOPSIS */
  24         AROS_LHA(APTR,    address, A0),
  25         AROS_LHA(ULONG *, length,  A1),
  26         AROS_LHA(ULONG,   flags,  D0),
  27
  28 /*  LOCATION */
  29         struct ExecBase *, SysBase, 128, Exec)
  30
  31 /*  FUNCTION
  32         Do everything necessary to make CPU caches aware that a DMA has
  33         happened.
  34
  35     INPUTS
  36         address - Virtual address of memory affected by the DMA
  37         *length - Number of bytes affected
  38         flags   - DMA_NoModify    - Indicate that the memory did not change.
  39                   DMA_ReadFromRAM - Indicate that the DMA goes from RAM
  40                                     to the device. Set this bit in
  41                                     both calls.
  42
  43     RESULT
  44
  45     NOTES
  46         DMA must follow a call to CachePreDMA() and must be followed
  47         by a call to CachePostDMA().
  48
  49     EXAMPLE
  50
  51     BUGS
  52
  53     SEE ALSO
  54         CachePreDMA()
  55
  56     INTERNALS
  57     Due to the strong cache coherency of x86 systems this function
  58     is actually not needed. CPU snoops the address lines and
  59     invalidate all cache which is out-of-date. It is valid for both
  60     D and I caches). Even a BM-DMA transfer are perfectly safe here.
  61
  62 ******************************************************************************/
  63 {
  64     AROS_LIBFUNC_INIT
  65
  66     AROS_LIBFUNC_EXIT
  67 } /* CachePostDMA */
  68