Mark
61 lines
1.6 KiB
C
61 lines
1.6 KiB
C
#include "sys/amd64/hw/timer.h"
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#include "sys/amd64/hw/ioapic.h"
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#include "sys/amd64/hw/idt.h"
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#include "sys/amd64/hw/apic.h"
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#include "sys/amd64/hw/irq.h"
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#include "sys/amd64/hw/io.h"
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#include "sys/spin.h"
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#include "sys/time.h"
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#include "sys/debug.h"
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#include "sys/amd64/cpu.h"
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#include "sys/assert.h"
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#define TIMER_PIT 1
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#define PIT_FREQ_BASE 1193182
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// Gives ~1kHz, ~1ms resolution
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#define PIT_DIV 1193
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#define PIT_CH0 0x40
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#define PIT_CMD 0x43
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uint64_t system_time = 0;
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static uint32_t timer_tick(void *arg) {
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switch ((uint64_t) arg) {
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case TIMER_PIT:
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// Each tick is approx. 1ms, so add 1ms to system time
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system_time += 1000000;
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break;
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}
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return IRQ_UNHANDLED;
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}
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void amd64_global_timer_init(void) {
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// Initialize global timer
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// Setup PIT
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outb(PIT_CMD, (3 << 4 /* Write lo/hi */) | (2 << 1 /* Rate generator */));
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outb(PIT_CH0, PIT_DIV & 0xFF);
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outb(PIT_CH0, PIT_DIV >> 8);
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irq_add_handler(2, timer_tick, (void *) TIMER_PIT);
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amd64_ioapic_unmask(2);
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}
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void amd64_timer_init(void) {
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if (get_cpu()->processor_id == 0) {
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amd64_global_timer_init();
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}
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// Initialize CPU-local timer
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kdebug("cpu%d: initializing timer\n", get_cpu()->processor_id);
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// No need to calibrate CPU-local timers - precision timer is global
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// LAPIC Timer is only used to trigger task switches
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LAPIC(LAPIC_REG_TMRDIV) = 0x3;
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LAPIC(LAPIC_REG_LVTT) = 32 | (1 << 17);
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LAPIC(LAPIC_REG_TMRINITCNT) = 10000;
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LAPIC(LAPIC_REG_TMRCURRCNT) = 0;
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get_cpu()->ticks = 0;
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}
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