rom/exec/opendevice.c

   1 /*
   2     Copyright © 1995-2017, 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 #include "exec_intern.h"
  19 #include "exec_debug.h"
  20 #include "exec_locks.h"
  21
  22 /*****************************************************************************
  23
  24     NAME */
  25
  26         AROS_LH4(LONG, OpenDevice,
  27
  28 /*  SYNOPSIS */
  29         AROS_LHA(CONST_STRPTR,       devName,    A0),
  30         AROS_LHA(IPTR,               unitNumber, D0),
  31         AROS_LHA(struct IORequest *, iORequest,  A1),
  32         AROS_LHA(ULONG,              flags,      D1),
  33
  34 /*  LOCATION */
  35         struct ExecBase *, SysBase, 74, Exec)
  36
  37 /*  FUNCTION
  38         Tries to open a device and fill the iORequest structure.  An error
  39         is returned if this fails, 0 if all went well.
  40
  41         If the device doesn't exist in the current system device list, then
  42         first the system ROMtag module list, then if the DOS is running,
  43         then the DEVS: directory will be tried.
  44
  45     INPUTS
  46         devName    - Pointer to the devices's name.
  47         unitNumber - The unit number. Most often 0. In some special cases this can be
  48                      a pointer to something (device-dependent).
  49         iORequest  - Pointer to device specific information.
  50                      Will be filled out by the device.
  51                      Must lie in public (or at least shared) memory.
  52         flags      - Some flags to give to the device.
  53
  54     RESULT
  55         Error code or 0 if all went well. The same value can be found
  56         in the io_Error field.
  57
  58     NOTES
  59         Return type is internally extended to LONG in all existing official ROMs
  60         (EXT.W D0 + EXT.L D0) DoIO() and WaitIO() do the same.
  61         Many programs assume LONG return code, even some WB utilities.
  62
  63     EXAMPLE
  64
  65     BUGS
  66
  67     SEE ALSO
  68         OpenDevice()
  69
  70     INTERNALS
  71
  72 *****************************************************************************/
  73 {
  74     AROS_LIBFUNC_INIT
  75
  76     /*
  77      * Kludge for compatibility with V40 kickstart. DO NOT depend on this!
  78      * See TaggedOpenLibrary() for more info.
  79      */
  80     switch ((IPTR)devName)
  81     {
  82     case 0:
  83         devName = "timer.device";
  84         break;
  85
  86     case 1:
  87         devName = "input.device";
  88         break;
  89     }
  90
  91     D(bug("[exec] OpenDevice(\"%s\", %ld, 0x%p, %d) by \"%s\"\n", devName, unitNumber, iORequest,
  92           flags, GET_THIS_TASK->tc_Node.ln_Name));
  93
  94     /* Arbitrate for the device list */
  95     EXEC_LOCK_LIST_READ_AND_FORBID(&SysBase->DeviceList);
  96
  97     /* Look for the device in our list */
  98     iORequest->io_Unit   = NULL;
  99
 100     iORequest->io_Device = (struct Device *)FindName(&SysBase->DeviceList, devName);
 101
 102     EXEC_UNLOCK_LIST(&SysBase->DeviceList);
 103
 104     D(bug("[OpenDevice] Found resident 0x%p\n", iORequest->io_Device));
 105
 106     /* Something found ? */
 107     if (iORequest->io_Device)
 108     {
 109         iORequest->io_Error = 0;
 110
 111         /* Call Open vector. */
 112         AROS_LVO_CALL3NR(void,
 113             AROS_LCA(struct IORequest *,iORequest,A1),
 114             AROS_LCA(IPTR, unitNumber,D0),
 115             AROS_LCA(ULONG,flags,D1),
 116             struct Device *, iORequest->io_Device, 1, dev);
 117
 118         /* Check for error */
 119         if (iORequest->io_Error)
 120             /* Mark request as non-open */
 121             iORequest->io_Device=NULL;
 122     }
 123     else
 124         iORequest->io_Error = IOERR_OPENFAIL;
 125
 126     /*
 127      *  We cannot handle loading devices from disk. But thankfully this is
 128      *  taken care of by dos.library (well lddemon really). It replaces
 129      *  this function with one of its own via the SetFunction() call.
 130      */
 131
 132     /* All done. */
 133     Permit();
 134
 135     D(bug("[OpenDevice] Returning device 0x%p, unit 0x%p, error %d\n", iORequest->io_Device, iORequest->io_Unit, iORequest->io_Error));
 136
 137     return iORequest->io_Error;
 138
 139     AROS_LIBFUNC_EXIT
 140 } /* OpenDevice */
 141