rom/exec/opendevice.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Open a device.
   6     Lang: english
   7 */
   8 #include <aros/config.h>
   9 #include <exec/execbase.h>
  10 #include <exec/devices.h>
  11 #include <exec/io.h>
  12 #include <exec/errors.h>
  13 #include <aros/libcall.h>
  14 #include <exec/libraries.h>
  15 #include <proto/exec.h>
  16
  17 #ifndef DEBUG_SetFunction
  18 #   define DEBUG_SetFunction 0
  19 #endif
  20 #undef DEBUG
  21 #if DEBUG_SetFunction
  22 #   define DEBUG 1
  23 #endif
  24 #include <aros/debug.h>
  25 #undef kprintf
  26
  27 char *const timername = "timer.device";
  28 char *const inputname = "input.device";
  29
  30 /*****************************************************************************
  31
  32     NAME */
  33
  34         AROS_LH4(BYTE, OpenDevice,
  35
  36 /*  SYNOPSIS */
  37         AROS_LHA(CONST_STRPTR,       devName,    A0),
  38         AROS_LHA(ULONG,              unitNumber, D0),
  39         AROS_LHA(struct IORequest *, iORequest,  A1),
  40         AROS_LHA(ULONG,              flags,      D1),
  41
  42 /*  LOCATION */
  43         struct ExecBase *, SysBase, 74, Exec)
  44
  45 /*  FUNCTION
  46         Tries to open a device and fill the iORequest structure.  An error
  47         is returned if this fails, 0 if all went well.
  48
  49         If the device doesn't exist in the current system device list, then
  50         first the system ROMtag module list, then if the DOS is running,
  51         then the DEVS: directory will be tried.
  52
  53     INPUTS
  54         devName    - Pointer to the devices's name.
  55         unitNumber - The unit number. Most often 0.
  56         iORequest  - Pointer do device specific information.
  57                      Will be filled out by the device.
  58                      Must lie in public (or at least shared) memory.
  59         flags      - Some flags to give to the device.
  60
  61     RESULT
  62         Error code or 0 if all went well. The same value can be found
  63         in the io_Error field.
  64
  65     NOTES
  66
  67     EXAMPLE
  68
  69     BUGS
  70
  71     SEE ALSO
  72         OpenDevice()
  73
  74     INTERNALS
  75
  76 *****************************************************************************/
  77 {
  78     AROS_LIBFUNC_INIT
  79
  80     AROS_LIBBASE_EXT_DECL(struct ExecBase *,SysBase)
  81     struct Device *device;
  82     BYTE ret=IOERR_OPENFAIL;
  83
  84     D(bug("OpenDevice $%lx $%lx $%lx %ld (\"%s\") by \"%s\"\n", devName, unitNumber, iORequest,
  85         flags, (devName > (STRPTR)1) ? devName : (UBYTE *)"(null)", SysBase->ThisTask->tc_Node.ln_Name));
  86
  87     /* Arbitrate for the device list */
  88     Forbid();
  89
  90 #if (AROS_FLAVOUR & AROS_FLAVOUR_NATIVE)
  91     /*
  92         Kludge for compatibility with V40 kickstart. DO NOT depend on this!
  93         See TaggedOpenLibrary() for more info.
  94     */
  95     if     (devName == (STRPTR)0) devName = timername;
  96     else if(devName == (STRPTR)1) devName = inputname;
  97 #endif
  98
  99     /* Look for the device in our list */
 100     device=(struct Device *)FindName(&SysBase->DeviceList,devName);
 101
 102     /* Something found ? */
 103     if(device!=NULL)
 104     {
 105         /* Init iorequest */
 106         iORequest->io_Error=0;
 107         iORequest->io_Device=device;
 108         iORequest->io_Unit = NULL;
 109
 110         /* Call Open vector. */
 111         AROS_LVO_CALL3NR(
 112             AROS_LCA(struct IORequest *,iORequest,A1),
 113             AROS_LCA(ULONG,unitNumber,D0),
 114             AROS_LCA(ULONG,flags,D1),
 115             struct Device *, device, 1, dev
 116         );
 117
 118         /* Check for error */
 119         ret=iORequest->io_Error;
 120         if(ret)
 121             /* Mark request as non-open */
 122             iORequest->io_Device=NULL;
 123     }
 124
 125     /*
 126      *  We cannot handle loading devices from disk. But thankfully this is
 127      *  taken care of by dos.library (well lddemon really). It replaces
 128      *  this function with one of its own via the SetFunction() call.
 129      */
 130
 131     /* All done. */
 132     Permit();
 133     return ret;
 134     AROS_LIBFUNC_EXIT
 135 } /* OpenDevice */
 136