arch/all-unix/timer/timer_init.c

   1 /*
   2     Copyright © 1995-2014, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 /*
   7  * UNIX-hosted timer driver.
   8  * Unix operating systems have only one usable timer, producing SIGALRM.
   9  * In this implementation we run the timer with a fixed frequency, which
  10  * is a multiple of VBlank frequency.
  11  * TODO: Rewrite UNIX-hosted timer.device to use variable delays, for improved accuracy.
  12  */
  13
  14 #include <aros/bootloader.h>
  15 #include <aros/debug.h>
  16 #include <aros/symbolsets.h>
  17 #include <exec/execbase.h>
  18 #include <exec/interrupts.h>
  19 #include <hardware/intbits.h>
  20 #include <proto/arossupport.h>
  21 #include <proto/bootloader.h>
  22 #include <proto/exec.h>
  23 #include <proto/hostlib.h>
  24 #include <proto/kernel.h>
  25
  26 #include "timer_intern.h"
  27 #include "timer_macros.h"
  28
  29 #define timeval sys_timeval
  30
  31 #include <signal.h>
  32 #include <sys/time.h>
  33 #include <string.h>
  34
  35 #undef timeval
  36
  37 /* Android is not a true Linux ;-) */
  38 #ifdef HOST_OS_android
  39 #undef HOST_OS_linux
  40 #endif
  41
  42 #ifdef HOST_OS_linux
  43 #define LIBC_NAME "libc.so.6"
  44 #endif
  45
  46 #ifdef HOST_OS_darwin
  47 #define LIBC_NAME "libSystem.dylib"
  48 #endif
  49
  50 #ifndef LIBC_NAME
  51 #define LIBC_NAME "libc.so"
  52 #endif
  53
  54 /*
  55  * In Linux stdlib.h #define's atoi() to something internal, causing link failure
  56  * because we link our kickstart binaries against AROS libraries, and not against
  57  * host OS ones.
  58  * Explicit prototype here avoids this.
  59  */
  60 int atoi(const char *nptr);
  61
  62 /* Handle periodic timer and drive exec VBlank */
  63 static void TimerTick(struct TimerBase *TimerBase, struct ExecBase *SysBase)
  64 {
  65     /* Increment EClock value and process microhz requests */
  66     ADDTIME(&TimerBase->tb_CurrentTime, &TimerBase->tb_Platform.tb_VBlankTime);
  67     ADDTIME(&TimerBase->tb_Elapsed, &TimerBase->tb_Platform.tb_VBlankTime);
  68     TimerBase->tb_ticks_total++;
  69
  70     handleMicroHZ(TimerBase, SysBase);
  71
  72     /* Now handle VBlank emulation via divisor */
  73     TimerBase->tb_Platform.tb_TimerCount++;
  74     if (TimerBase->tb_Platform.tb_TimerCount == TimerBase->tb_Platform.tb_VBlankTicks)
  75     {
  76         vblank_Cause(SysBase);
  77         handleVBlank(TimerBase, SysBase);
  78
  79         TimerBase->tb_Platform.tb_TimerCount = 0;
  80     }
  81 }
  82
  83 #define KernelBase TimerBase->tb_KernelBase
  84
  85 static int Timer_Init(struct TimerBase *TimerBase)
  86 {
  87     APTR BootLoaderBase;
  88     struct itimerval interval;
  89     int ret;
  90
  91     HostLibBase = OpenResource("hostlib.resource");
  92     if (!HostLibBase)
  93         return FALSE;
  94
  95     TimerBase->tb_Platform.libcHandle = HostLib_Open(LIBC_NAME, NULL);
  96     if (!TimerBase->tb_Platform.libcHandle)
  97         return FALSE;
  98
  99     TimerBase->tb_Platform.setitimer = HostLib_GetPointer(TimerBase->tb_Platform.libcHandle, "setitimer", NULL);
 100     if (!TimerBase->tb_Platform.setitimer)
 101         return FALSE;
 102
 103     /* Install timer IRQ handler */
 104 #if DEBUG
 105     /* Uses ITIMER_VIRTUAL/SIGVTALRM instead of the
 106      * ITIMER_REAL/SIGALRM in debug builds, so
 107      * that stepping though code won't have to deal
 108      * with constant SIGALRM processing.
 109      *
 110      * NOTE: This will cause the AROS clock to march slower
 111      *       than the host clock in debug builds!
 112      */
 113     TimerBase->tb_TimerIRQHandle = KrnAddIRQHandler(SIGVTALRM, TimerTick, TimerBase, SysBase);
 114 #else
 115     TimerBase->tb_TimerIRQHandle = KrnAddIRQHandler(SIGALRM, TimerTick, TimerBase, SysBase);
 116 #endif
 117     if (!TimerBase->tb_TimerIRQHandle)
 118         return FALSE;
 119
 120     /* Our defaults: 50 Hz VBlank and 4x timer rate. 1x gives very poor results. */
 121     SysBase->VBlankFrequency = 50;
 122     TimerBase->tb_Platform.tb_VBlankTicks = 4;
 123
 124     /*
 125      * Since we are software-driven, we can just ask the user which
 126      * frequencies he wishes to use.
 127      */
 128     BootLoaderBase = OpenResource("bootloader.resource");
 129     if (BootLoaderBase)
 130     {
 131         struct List *args = GetBootInfo(BL_Args);
 132
 133         if (args)
 134         {
 135             struct Node *node;
 136
 137             for (node = args->lh_Head; node->ln_Succ; node = node->ln_Succ)
 138             {
 139                 if (strncasecmp(node->ln_Name, "vblank=", 7) == 0)
 140                     SysBase->VBlankFrequency = atoi(&node->ln_Name[7]);
 141                 else if (strncasecmp(node->ln_Name, "tickrate=", 9) == 0)
 142                     TimerBase->tb_Platform.tb_VBlankTicks = atoi(&node->ln_Name[9]);
 143             }
 144         }
 145     }
 146
 147     /* Calculate effective EClock timer frequency. Set it also in ExecBase public field. */
 148     TimerBase->tb_eclock_rate = SysBase->VBlankFrequency * TimerBase->tb_Platform.tb_VBlankTicks;
 149     SysBase->ex_EClockFrequency = TimerBase->tb_eclock_rate;
 150     D(bug("[Timer_Init] Timer frequency is %d\n", TimerBase->tb_eclock_rate));
 151
 152     /* Calculate timer period in us */
 153     TimerBase->tb_Platform.tb_VBlankTime.tv_secs  = 0;
 154     TimerBase->tb_Platform.tb_VBlankTime.tv_micro = 1000000 / TimerBase->tb_eclock_rate;
 155
 156     /* Start up our system timer. */
 157     interval.it_interval.tv_sec  = interval.it_value.tv_sec  = 0;
 158     interval.it_interval.tv_usec = interval.it_value.tv_usec = TimerBase->tb_Platform.tb_VBlankTime.tv_micro;
 159
 160     HostLib_Lock();
 161
 162 #if DEBUG
 163     ret = TimerBase->tb_Platform.setitimer(ITIMER_VIRTUAL, &interval, NULL);
 164 #else
 165     ret = TimerBase->tb_Platform.setitimer(ITIMER_REAL, &interval, NULL);
 166 #endif
 167     AROS_HOST_BARRIER
 168
 169     HostLib_Unlock();
 170
 171     D(bug("[Timer_Init] setitimer() returned %d\n", ret));
 172     return !ret;
 173 }
 174
 175 static int Timer_Expunge(struct TimerBase *TimerBase)
 176 {
 177     if (!HostLibBase)
 178         return TRUE;
 179
 180     if (TimerBase->tb_TimerIRQHandle)
 181         KrnRemIRQHandler(TimerBase->tb_TimerIRQHandle);
 182
 183     if (TimerBase->tb_Platform.libcHandle)
 184         HostLib_Close(TimerBase->tb_Platform.libcHandle, NULL);
 185
 186     return TRUE;
 187 }
 188
 189 ADD2INITLIB(Timer_Init, 0)
 190 ADD2EXPUNGELIB(Timer_Expunge, 0)