kernel/fiasco/src/kern/arm/bsp/realview/timer-arm-mptimer-realview.cpp

   1 // --------------------------------------------------------------------------
   2 IMPLEMENTATION[arm && mptimer]:
   3
   4 PRIVATE static Mword Timer::interval()
   5 {
   6   Mword v = Io::read<Mword>(Timer_sp804::System_control);
   7   v |= Timer_sp804::Timclk << Timer_sp804::Timer0_enable;
   8   Io::write<Mword>(v, Timer_sp804::System_control);
   9
  10   Mword frequency = 1000000;
  11   Mword timer_start = ~0UL;
  12   unsigned factor = 5;
  13   Mword sp_c = timer_start - frequency / 1000 * (1 << factor);
  14
  15   Io::write<Mword>(0, Timer_sp804::Ctrl_0);
  16   Io::write<Mword>(timer_start, Timer_sp804::Value_0);
  17   Io::write<Mword>(timer_start, Timer_sp804::Load_0);
  18   Io::write<Mword>(  Timer_sp804::Ctrl_enable
  19                    | Timer_sp804::Ctrl_periodic,
  20                    Timer_sp804::Ctrl_0);
  21
  22   Mword vc = start_as_counter();
  23   while (sp_c < Io::read<Mword>(Timer_sp804::Value_0))
  24     ;
  25   Mword interval = (vc - stop_counter()) >> factor;
  26   Io::write<Mword>(0, Timer_sp804::Ctrl_0);
  27   return interval;
  28 }