rom/exec/opendevice.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Open a device.
   6     Lang: english
   7 */
   8
   9 #include <aros/debug.h>
  10 #include <exec/execbase.h>
  11 #include <exec/devices.h>
  12 #include <exec/io.h>
  13 #include <exec/errors.h>
  14 #include <aros/libcall.h>
  15 #include <exec/libraries.h>
  16 #include <proto/exec.h>
  17
  18 /*****************************************************************************
  19
  20     NAME */
  21
  22         AROS_LH4(LONG, OpenDevice,
  23
  24 /*  SYNOPSIS */
  25         AROS_LHA(CONST_STRPTR,       devName,    A0),
  26         AROS_LHA(IPTR,               unitNumber, D0),
  27         AROS_LHA(struct IORequest *, iORequest,  A1),
  28         AROS_LHA(ULONG,              flags,      D1),
  29
  30 /*  LOCATION */
  31         struct ExecBase *, SysBase, 74, Exec)
  32
  33 /*  FUNCTION
  34         Tries to open a device and fill the iORequest structure.  An error
  35         is returned if this fails, 0 if all went well.
  36
  37         If the device doesn't exist in the current system device list, then
  38         first the system ROMtag module list, then if the DOS is running,
  39         then the DEVS: directory will be tried.
  40
  41     INPUTS
  42         devName    - Pointer to the devices's name.
  43         unitNumber - The unit number. Most often 0. In some special cases this can be
  44                      a pointer to something (device-dependent).
  45         iORequest  - Pointer to device specific information.
  46                      Will be filled out by the device.
  47                      Must lie in public (or at least shared) memory.
  48         flags      - Some flags to give to the device.
  49
  50     RESULT
  51         Error code or 0 if all went well. The same value can be found
  52         in the io_Error field.
  53
  54     NOTES
  55         Return type is internally extended to LONG in all existing official ROMs
  56         (EXT.W D0 + EXT.L D0) DoIO() and WaitIO() do the same.
  57         Many programs assume LONG return code, even some WB utilities.
  58
  59     EXAMPLE
  60
  61     BUGS
  62
  63     SEE ALSO
  64         OpenDevice()
  65
  66     INTERNALS
  67
  68 *****************************************************************************/
  69 {
  70     AROS_LIBFUNC_INIT
  71
  72     /*
  73      * Kludge for compatibility with V40 kickstart. DO NOT depend on this!
  74      * See TaggedOpenLibrary() for more info.
  75      */
  76     switch ((IPTR)devName)
  77     {
  78     case 0:
  79         devName = "timer.device";
  80         break;
  81
  82     case 1:
  83         devName = "input.device";
  84         break;
  85     }
  86
  87     D(bug("[exec] OpenDevice(\"%s\", %ld, 0x%p, %d) by \"%s\"\n", devName, unitNumber, iORequest,
  88           flags, GET_THIS_TASK->tc_Node.ln_Name));
  89
  90     /* Arbitrate for the device list */
  91     Forbid();
  92
  93     /* Look for the device in our list */
  94     iORequest->io_Unit   = NULL;
  95     iORequest->io_Device = (struct Device *)FindName(&SysBase->DeviceList, devName);
  96     D(bug("[OpenDevice] Found resident 0x%p\n", iORequest->io_Device));
  97
  98     /* Something found ? */
  99     if (iORequest->io_Device)
 100     {
 101         iORequest->io_Error = 0;
 102
 103         /* Call Open vector. */
 104         AROS_LVO_CALL3NR(void,
 105             AROS_LCA(struct IORequest *,iORequest,A1),
 106             AROS_LCA(IPTR, unitNumber,D0),
 107             AROS_LCA(ULONG,flags,D1),
 108             struct Device *, iORequest->io_Device, 1, dev);
 109
 110         /* Check for error */
 111         if (iORequest->io_Error)
 112             /* Mark request as non-open */
 113             iORequest->io_Device=NULL;
 114     }
 115     else
 116         iORequest->io_Error = IOERR_OPENFAIL;
 117
 118     /*
 119      *  We cannot handle loading devices from disk. But thankfully this is
 120      *  taken care of by dos.library (well lddemon really). It replaces
 121      *  this function with one of its own via the SetFunction() call.
 122      */
 123
 124     /* All done. */
 125     Permit();
 126
 127     D(bug("[OpenDevice] Returning device 0x%p, unit 0x%p, error %d\n", iORequest->io_Device, iORequest->io_Unit, iORequest->io_Error));
 128
 129     return iORequest->io_Error;
 130
 131     AROS_LIBFUNC_EXIT
 132 } /* OpenDevice */
 133