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

   1 // --------------------------------------------------------------------------
   2 IMPLEMENTATION[arm && mptimer]:
   3
   4 #include "platform.h"
   5 #include "timer_sp804.h"
   6
   7 PRIVATE static Mword Timer::interval()
   8 {
   9   Timer_sp804 timer(Kmem::mmio_remap(Mem_layout::Timer0_phys_base));
  10   Platform::system_control->modify<Mword>(Platform::System_control::Timer0_enable, 0, 0);
  11
  12   Mword frequency = 1000000;
  13   Mword timer_start = ~0UL;
  14   unsigned factor = 5;
  15   Mword sp_c = timer_start - frequency / 1000 * (1 << factor);
  16
  17   timer.disable();
  18   timer.counter_value(timer_start);
  19   timer.reload_value(timer_start);
  20   timer.enable(Timer_sp804::Ctrl_periodic);
  21
  22   Mword vc = start_as_counter();
  23   while (sp_c < timer.counter())
  24     ;
  25   Mword interval = (vc - stop_counter()) >> factor;
  26   timer.disable();
  27   return interval;
  28 }