rom/timer/timer_init.c

   1 /*
   2     Copyright © 1995-2017, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Timer startup and device commands, reference code
   6
   7     This code uses VBlank interrupt as a source for both units. This can be
   8     considered a reference code for building basic timer.device implementations,
   9     using a periodic timer. However, in real life you'll want better timing source
  10     than 50 Hz, so you'll likely replace this with your own code.
  11 */
  12
  13 /****************************************************************************************/
  14
  15 #include <exec/types.h>
  16 #include <exec/io.h>
  17 #include <exec/errors.h>
  18 #include <exec/devices.h>
  19 #include <exec/alerts.h>
  20 #include <exec/initializers.h>
  21 #include <devices/timer.h>
  22 #include <hardware/intbits.h>
  23
  24 #include <proto/exec.h>
  25 #include <proto/execlock.h>
  26 #include <proto/timer.h>
  27
  28 #include <aros/symbolsets.h>
  29 #include <aros/debug.h>
  30
  31 #include LC_LIBDEFS_FILE
  32
  33 #include "timer_macros.h"
  34
  35 /* exec.library VBlank interrupt handler  */
  36 static AROS_INTH1(VBlankInt, struct TimerBase *, TimerBase)
  37 {
  38     AROS_INTFUNC_INIT
  39
  40     /*
  41      * First increment the current time. No need to Disable() here as
  42      * there are no other interrupts that are allowed to interrupt us
  43      * that can do anything with this.
  44      */
  45     ADDTIME(&TimerBase->tb_CurrentTime, &TimerBase->tb_Platform.tb_VBlankTime);
  46     ADDTIME(&TimerBase->tb_Elapsed, &TimerBase->tb_Platform.tb_VBlankTime);
  47     TimerBase->tb_ticks_total++;
  48
  49     /*
  50      * Now go to handle requests.
  51      * We are called at rather low rate, so don't bother and process both units.
  52      */
  53     handleMicroHZ(TimerBase, SysBase);
  54     handleVBlank(TimerBase, SysBase);
  55
  56     return 0;
  57
  58     AROS_INTFUNC_EXIT
  59 }
  60
  61 /****************************************************************************************/
  62
  63 static int GM_UNIQUENAME(Init)(LIBBASETYPEPTR LIBBASE)
  64 {
  65     struct Interrupt *is;
  66
  67 #if defined(__AROSEXEC_SMP__)
  68     struct ExecLockBase *ExecLockBase;
  69     if ((ExecLockBase = OpenResource("execlock.resource")) != NULL)
  70     {
  71         LIBBASE->tb_ExecLockBase = ExecLockBase;
  72         LIBBASE->tb_ListLock = AllocLock();
  73     }
  74 #endif
  75
  76     /* If no frequency is set, assume 50Hz */
  77     if (SysBase->VBlankFrequency == 0)
  78         SysBase->VBlankFrequency = 50;
  79
  80     /*
  81      * Here we do no checks, we simply assume we have working VBlank interrupt,
  82      * from whatever source it is.
  83      */
  84
  85     LIBBASE->tb_eclock_rate = SysBase->VBlankFrequency;
  86     D(bug("[timer] Timer IRQ is %d, frequency is %u Hz\n", INTB_VERTB, LIBBASE->tb_eclock_rate));
  87
  88     /* Calculate timer period in us */
  89     LIBBASE->tb_Platform.tb_VBlankTime.tv_secs  = 0;
  90     LIBBASE->tb_Platform.tb_VBlankTime.tv_micro = 1000000 / LIBBASE->tb_eclock_rate;
  91
  92     D(bug("Timer period: %ld secs, %ld micros\n",
  93         LIBBASE->tb_Platform.tb_VBlankTime.tv_secs, LIBBASE->tb_Platform.tb_VBlankTime.tv_micro));
  94
  95     /* Start up the interrupt server */
  96     is = AllocMem(sizeof(struct Interrupt), MEMF_PUBLIC);
  97     if (is)
  98     {
  99         is->is_Node.ln_Pri = 0;
 100         is->is_Node.ln_Type = NT_INTERRUPT;
 101         is->is_Node.ln_Name = (STRPTR)MOD_NAME_STRING;
 102         is->is_Code = (VOID_FUNC)VBlankInt;
 103         is->is_Data = LIBBASE;
 104
 105         AddIntServer(INTB_VERTB, is);
 106         LIBBASE->tb_TimerIRQHandle = is;
 107
 108         return TRUE;
 109     }
 110
 111     return FALSE;
 112 }
 113
 114 /****************************************************************************************/
 115
 116 ADD2INITLIB(GM_UNIQUENAME(Init), 0)