kern/arch/riscv/time.c

   1 #include <arch/time.h>
   2 #include <ros/common.h>
   3 #include <arch/trap.h>
   4 #include <arch/arch.h>
   5 #include <stdio.h>
   6 #include <assert.h>
   7
   8 system_timing_t system_timing = {0};
   9
  10 void
  11 timer_init(void)
  12 {
  13         system_timing.tsc_freq = TSC_HZ;
  14         cprintf("TSC Frequency: %llu\n", system_timing.tsc_freq);
  15 }
  16
  17 void
  18 set_core_timer(uint32_t usec, bool periodic)
  19 {
  20         // we could implement periodic timers using one-shot timers,
  21         // but for now we only support one-shot
  22         assert(!periodic);
  23
  24         if (usec)
  25         {
  26                 uint32_t clocks =  (uint64_t)usec*TSC_HZ/1000000;
  27
  28                 int8_t irq_state = 0;
  29                 disable_irqsave(&irq_state);
  30
  31                 mtpcr(PCR_COUNT, 0);
  32                 mtpcr(PCR_COMPARE, clocks);
  33                 mtpcr(PCR_SR, mfpcr(PCR_SR) | (1 << (IRQ_TIMER+SR_IM_SHIFT)));
  34
  35                 enable_irqsave(&irq_state);
  36         }
  37         else
  38         {
  39                 mtpcr(PCR_SR, mfpcr(PCR_SR) & ~(1 << (IRQ_TIMER+SR_IM_SHIFT)));
  40         }
  41 }
  42
  43 void
  44 udelay(uint64_t usec)
  45 {
  46         if (system_timing.tsc_freq != 0)
  47         {
  48                 uint64_t start, end, now;
  49
  50                 start = read_tsc();
  51                 end = start + (system_timing.tsc_freq * usec) / 1000000;
  52
  53                 do
  54                 {
  55                         cpu_relax();
  56                         now = read_tsc();
  57                 } while (now < end || (now > start && end < start));
  58         }
  59         else panic("udelay() was called before timer_init(), moron!");
  60 }