iodev/virt_timer.h

   1 ////////////////////////////////////////////////////////////////////////
   2 // $Id: virt_timer.h,v 1.15 2008/02/15 22:05:43 sshwarts Exp $
   3 /////////////////////////////////////////////////////////////////////////
   4 //
   5 //  Copyright (C) 2002  MandrakeSoft S.A.
   6 //
   7 //    MandrakeSoft S.A.
   8 //    43, rue d'Aboukir
   9 //    75002 Paris - France
  10 //    http://www.linux-mandrake.com/
  11 //    http://www.mandrakesoft.com/
  12 //
  13 //  This library is free software; you can redistribute it and/or
  14 //  modify it under the terms of the GNU Lesser General Public
  15 //  License as published by the Free Software Foundation; either
  16 //  version 2 of the License, or (at your option) any later version.
  17 //
  18 //  This library is distributed in the hope that it will be useful,
  19 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21 //  Lesser General Public License for more details.
  22 //
  23 //  You should have received a copy of the GNU Lesser General Public
  24 //  License along with this library; if not, write to the Free Software
  25 //  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  26 /////////////////////////////////////////////////////////////////////////
  27
  28 #ifndef _BX_VIRT_TIMER_H
  29 #define _BX_VIRT_TIMER_H
  30
  31 // should be adjusted if want to support more SMP processors
  32 #define BX_MAX_VIRTUAL_TIMERS (32)
  33 #define BX_NULL_VIRTUAL_TIMER_HANDLE 10000
  34
  35 #define BX_MAX_VIRTUAL_TIME (0x7fffffff)
  36
  37 class bx_virt_timer_c : public logfunctions {
  38 private:
  39
  40   struct {
  41     bx_bool inUse;      // Timer slot is in-use (currently registered).
  42     Bit64u  period;     // Timer periodocity in virtual useconds.
  43     Bit64u  timeToFire; // Time to fire next (in virtual useconds).
  44     bx_bool active;     // 0=inactive, 1=active.
  45     bx_bool continuous; // 0=one-shot timer, 1=continuous periodicity.
  46     bx_timer_handler_t funct;  // A callback function for when the
  47                                //   timer fires.
  48                                //   This function MUST return.
  49     void *this_ptr;            // The this-> pointer for C++ callbacks
  50                                //   has to be stored as well.
  51     char id[BxMaxTimerIDLen]; // String ID of timer.
  52   } timer[BX_MAX_VIRTUAL_TIMERS];
  53
  54   unsigned   numTimers;  // Number of currently allocated timers.
  55
  56   //Variables for the timer subsystem:
  57   Bit64u current_timers_time;
  58   Bit64u timers_next_event_time;
  59
  60   Bit64u last_sequential_time;
  61   bx_bool in_timer_handler;
  62
  63   //Variables for the time sync subsystem:
  64   Bit64u virtual_next_event_time;
  65   Bit64u current_virtual_time;
  66
  67   //Real time variables:
  68   Bit64u last_real_time;
  69   Bit64u total_real_usec;
  70   Bit64u last_realtime_delta;
  71   //System time variables:
  72   Bit64u last_usec;
  73   Bit64u usec_per_second;
  74   Bit64u stored_delta;
  75   Bit64u last_system_usec;
  76   Bit64u em_last_realtime;
  77   //Virtual timer variables:
  78   Bit64u total_ticks;
  79   Bit64u last_realtime_ticks;
  80   Bit64u ticks_per_second;
  81
  82   bx_bool init_done;
  83
  84   int system_timer_id;
  85
  86   //Whether or not to use virtual timers.
  87   bx_bool use_virtual_timers;
  88   bx_bool virtual_timers_realtime;
  89
  90   // A special null timer is always inserted in the timer[0] slot.  This
  91   // make sure that at least one timer is always active, and that the
  92   // duration is always less than a maximum 32-bit integer, so a 32-bit
  93   // counter can be used for the current countdown.
  94   static const Bit64u NullTimerInterval;
  95   static void nullTimer(void* this_ptr);
  96
  97   //Step the given number of cycles, optionally calling any timer handlers.
  98   void periodic(Bit64u time_passed);
  99
 100   //Called when next_event_time changes.
 101   void next_event_time_update(void);
 102
 103   //Called to advance the virtual time.
 104   // calls periodic as needed.
 105   void advance_virtual_time(Bit64u time_passed);
 106
 107 public:
 108
 109   bx_virt_timer_c();
 110   virtual ~bx_virt_timer_c() {}
 111
 112   //Get the current virtual time.
 113   //  This may return the same value on subsequent calls.
 114   Bit64u time_usec(void);
 115
 116   //Get the current virtual time.
 117   //  This will return a monotonically increasing value.
 118   // MUST NOT be called from within a timer handler.
 119   Bit64u time_usec_sequential(void);
 120
 121   //Register a timer handler to go off after a given interval.
 122   //Register a timer handler to go off with a periodic interval.
 123   int  register_timer(void *this_ptr, bx_timer_handler_t handler,
 124                          Bit32u useconds,
 125                          bx_bool continuous, bx_bool active, const char *id);
 126
 127   //unregister a previously registered timer.
 128   bx_bool unregisterTimer(unsigned timerID);
 129
 130   void start_timers(void);
 131
 132   //activate a deactivated but registered timer.
 133   void activate_timer(unsigned timer_index, Bit32u useconds,
 134                          bx_bool continuous);
 135
 136   //deactivate (but don't unregister) a currently registered timer.
 137   void deactivate_timer(unsigned timer_index);
 138
 139
 140   //Timer handler passed to pc_system
 141   static void pc_system_timer_handler(void* this_ptr);
 142
 143   //The real timer handler.
 144   void timer_handler();
 145
 146   //Initialization step #1 in constructor and for cleanup
 147   void setup(void);
 148
 149   //Initialization step #2
 150   void init(void);
 151
 152   void register_state(void);
 153 };
 154
 155 extern bx_virt_timer_c bx_virt_timer;
 156
 157 #endif // _BX_VIRT_TIMER_H