#define PMTIMER_HZ 3579545 // Underlying Hz of the PM Timer
#define PMTIMER_TO_PIT 3 // Ratio of pmtimer rate to pit rate
-u32 TimerKHz VARFSEG;
-u16 TimerPort VARFSEG;
+u32 TimerKHz VARFSEG = DIV_ROUND_UP(PMTIMER_HZ, 1000 * PMTIMER_TO_PIT);
+u16 TimerPort VARFSEG = PORT_PIT_COUNTER0;
u8 ShiftTSC VARFSEG;
t = (t + 1) >> 1;
}
TimerKHz = DIV_ROUND_UP((u32)t, 1000 * PMTIMER_TO_PIT);
+ TimerPort = 0;
dprintf(1, "CPU Mhz=%u\n", (TimerKHz << ShiftTSC) / 1000);
}
void
timer_setup(void)
{
- if (CONFIG_PMTIMER && TimerPort) {
- dprintf(3, "pmtimer already configured; will not calibrate TSC\n");
+ if (!CONFIG_TSC_TIMER || (CONFIG_PMTIMER && TimerPort != PORT_PIT_COUNTER0))
return;
- }
+ // Check if CPU has a timestamp counter
u32 eax, ebx, ecx, edx, cpuid_features = 0;
cpuid(0, &eax, &ebx, &ecx, &edx);
if (eax > 0)
cpuid(1, &eax, &ebx, &ecx, &cpuid_features);
-
- if (!(cpuid_features & CPUID_TSC)) {
- TimerPort = PORT_PIT_COUNTER0;
- TimerKHz = DIV_ROUND_UP(PMTIMER_HZ, 1000 * PMTIMER_TO_PIT);
- dprintf(3, "386/486 class CPU. Using TSC emulation\n");
- return;
- }
-
- tsctimer_setup();
+ if (cpuid_features & CPUID_TSC)
+ tsctimer_setup();
}
void
timer_read(void)
{
u16 port = GET_GLOBAL(TimerPort);
- if (!port)
+ if (CONFIG_TSC_TIMER && !port)
// Read from CPU TSC
return rdtscll() >> GET_GLOBAL(ShiftTSC);
if (CONFIG_PMTIMER && port != PORT_PIT_COUNTER0)
void
pit_setup(void)
{
+ if (!CONFIG_HARDWARE_IRQ)
+ return;
// timer0: binary count, 16bit count, mode 2
outb(PM_SEL_TIMER0|PM_ACCESS_WORD|PM_MODE2|PM_CNT_BINARY, PORT_PIT_MODE);
// maximum count of 0000H = 18.2Hz