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[INTERRUPTS] Enabling the APIC timer

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This commit is contained in:
Thomas Lovén 2017-01-24 12:19:47 +01:00
parent 9ae3b014da
commit d3d065b2e2
3 changed files with 64 additions and 1 deletions
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2
kernel/boot/kmain.c
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@ -11,6 +11,7 @@
#include <apic.h>
#include <sse.h>
#include <timer.h>
#include <pit.h>
void thread_function()
{
@ -18,6 +19,7 @@ void thread_function()
{
debug((char *)0x10000);
schedule();
pit_delay(100);
}
}

2
kernel/include/apic.h
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@ -4,6 +4,8 @@
void apic_init();
void apic_interrupt(uint8_t destination, uint8_t level, uint8_t type, uint8_t vector);
void apic_ack();
void apic_timer(uint64_t us);
void apic_timer_stop();
#define APIC_INT_LEVEL_ASSERT 0x1
#define APIC_INT_LEVEL_DEASSERT 0x0
#define APIC_INT_TYPE_FIXED 0x0

61
kernel/interrupts/apic.c
View File

@ -1,5 +1,5 @@
#include <apic.h>
#include <int.h>
#include <pit.h>
#include <msr.h>
#include <debug.h>
#include <mem.h>
@ -25,9 +25,28 @@
#define SPURIOUS_LVT_ENABLED 0x100
#define TIMER_LVT_ONESHOT 0x00000
#define TIMER_LVT_PERIODIC 0x20000
#define TIMER_LVT_DEADLINE 0x40000
#define R_TIMER_INIT 0x380
#define R_TIMER_CURR 0x390
#define R_TIMER_DIV 0x3E0
#define TIMER_DIV1 0xB
#define TIMER_DIV2 0x0
#define TIMER_DIV4 0x1
#define TIMER_DIV8 0x2
#define TIMER_DIV16 0x3
#define TIMER_DIV32 0x8
#define TIMER_DIV64 0x9
#define TIMER_DIV128 0xA
#define APIC(reg) apic[reg/4]
uint32_t volatile *apic = P2V(APIC_BASE);
uint32_t apic_ticks_per_us;
void apic_interrupt(uint8_t destination, uint8_t level, uint8_t type, uint8_t vector)
{
uint64_t data = ((level & 0x1)<<14) | ((type & 0x7)<<8) | vector;
@ -39,6 +58,36 @@ void apic_ack()
{
APIC(R_EOI) = 0;
}
registers_t *apic_timer_handler(registers_t *r)
{
// APIC timer timeout occurred
APIC(R_EOI) = 0;
debug_putch('-');
apic_timer(1000000);
return r;
}
void apic_timer(uint64_t us)
{
APIC(R_TIMER_DIV) = TIMER_DIV1;
APIC(R_TIMER_INIT) = us*apic_ticks_per_us;
APIC(R_TIMER_LVT) = TIMER_LVT_ONESHOT | INT_APIC_TIMER;
}
void apic_timer_stop()
{
APIC(R_TIMER_LVT) = LVT_MASKED | INT_APIC_TIMER;
}
uint32_t calibrate_apic_timer(uint32_t resolution)
{
// Use the PIT to calibrate the APIC timer
// Returns number of apic timer ticks per ms
APIC(R_TIMER_DIV) = TIMER_DIV1;
APIC(R_TIMER_LVT) = LVT_MASKED | INT_APIC_TIMER;
APIC(R_TIMER_INIT) = 0xFFFFFFFF;
pit_delay(resolution);
uint32_t ticks = APIC(R_TIMER_CURR);
return (0xFFFFFFFF-ticks)/resolution/1000;
}
void apic_init()
{
@ -55,4 +104,14 @@ void apic_init()
APIC(R_SPURIOUS) = SPURIOUS_LVT_ENABLED | INT_APIC_SPUR;
APIC(R_EOI) = 0;
// Calibrate timer
apic_ticks_per_us = calibrate_apic_timer(100);
debug_info("APIC - ticks per us:%d\n", apic_ticks_per_us);
debug(" corresponds to processor frequency: %d MHz\n", apic_ticks_per_us);
// Register temporary timer handler to go off every 10 ms
register_int_handler(INT_APIC_TIMER, apic_timer_handler);
apic_timer(1000000);
}