rom/exec/opendevice.c

   1 /*
   2     Copyright © 1995-2007, 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     struct Device *device;
  81     BYTE ret=IOERR_OPENFAIL;
  82
  83     D(bug("OpenDevice $%lx $%lx $%lx %ld (\"%s\") by \"%s\"\n", devName, unitNumber, iORequest,
  84         flags, (devName > (STRPTR)1) ? devName : (UBYTE *)"(null)", SysBase->ThisTask->tc_Node.ln_Name));
  85
  86     /* Arbitrate for the device list */
  87     Forbid();
  88
  89     /*
  90         Kludge for compatibility with V40 kickstart. DO NOT depend on this!
  91         See TaggedOpenLibrary() for more info.
  92     */
  93     if     (devName == (STRPTR)0) devName = timername;
  94     else if(devName == (STRPTR)1) devName = inputname;
  95
  96     /* Look for the device in our list */
  97     device=(struct Device *)FindName(&SysBase->DeviceList,devName);
  98
  99     /* Something found ? */
 100     if(device!=NULL)
 101     {
 102         /* Init iorequest */
 103         iORequest->io_Error=0;
 104         iORequest->io_Device=device;
 105         iORequest->io_Unit = NULL;
 106
 107         /* Call Open vector. */
 108         AROS_LVO_CALL3NR(void,
 109             AROS_LCA(struct IORequest *,iORequest,A1),
 110             AROS_LCA(ULONG,unitNumber,D0),
 111             AROS_LCA(ULONG,flags,D1),
 112             struct Device *, device, 1, dev
 113         );
 114
 115         /* Check for error */
 116         ret=iORequest->io_Error;
 117         if(ret)
 118             /* Mark request as non-open */
 119             iORequest->io_Device=NULL;
 120     }
 121
 122     /*
 123      *  We cannot handle loading devices from disk. But thankfully this is
 124      *  taken care of by dos.library (well lddemon really). It replaces
 125      *  this function with one of its own via the SetFunction() call.
 126      */
 127
 128     /* All done. */
 129     Permit();
 130     return ret;
 131     AROS_LIBFUNC_EXIT
 132 } /* OpenDevice */
 133