162 lines
2.9 KiB
C
162 lines
2.9 KiB
C
#include <stdint.h>
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#include <arch/io.h>
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#include <arch/traps.h>
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#include <tianole/arch.h>
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#include <tianole/early_log.h>
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#include <tianole/errno.h>
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#include <tianole/irq.h>
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#include <tianole/timer.h>
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#define PIC1_COMMAND 0x20
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#define PIC1_DATA 0x21
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#define PIC2_COMMAND 0xa0
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#define PIC2_DATA 0xa1
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#define PIC_EOI 0x20
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#define ICW1_INIT 0x10
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#define ICW1_ICW4 0x01
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#define ICW4_8086 0x01
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#define PIT_FREQUENCY 1193182u
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#define PIT_TARGET_HZ 100u
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#define PIT_COMMAND 0x43
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#define PIT_CHANNEL0 0x40
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#define PIT_MODE_RATE_GENERATOR 0x36
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#define IRQ_BASE 32u
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#define IRQ_TIMER 0u
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#define IRQ_COUNT 16u
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struct irq_action {
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irq_handler_t handler;
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void *data;
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};
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static struct irq_action irq_actions[IRQ_COUNT];
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static void pic_remap(void)
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{
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outb(PIC1_COMMAND, ICW1_INIT | ICW1_ICW4);
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io_wait();
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outb(PIC2_COMMAND, ICW1_INIT | ICW1_ICW4);
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io_wait();
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outb(PIC1_DATA, IRQ_BASE);
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io_wait();
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outb(PIC2_DATA, IRQ_BASE + 8);
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io_wait();
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outb(PIC1_DATA, 4);
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io_wait();
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outb(PIC2_DATA, 2);
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io_wait();
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outb(PIC1_DATA, ICW4_8086);
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io_wait();
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outb(PIC2_DATA, ICW4_8086);
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io_wait();
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}
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static void pic_mask_all_except_timer(void)
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{
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outb(PIC1_DATA, 0xfe);
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outb(PIC2_DATA, 0xff);
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}
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static void pic_send_eoi(uint8_t irq)
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{
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if (irq >= 8) {
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outb(PIC2_COMMAND, PIC_EOI);
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}
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outb(PIC1_COMMAND, PIC_EOI);
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}
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static void pit_init(void)
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{
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uint16_t divisor = (uint16_t)(PIT_FREQUENCY / PIT_TARGET_HZ);
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outb(PIT_COMMAND, PIT_MODE_RATE_GENERATOR);
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outb(PIT_CHANNEL0, (uint8_t)(divisor & 0xff));
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outb(PIT_CHANNEL0, (uint8_t)(divisor >> 8));
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}
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uint64_t arch_irq_save(void)
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{
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uint64_t flags;
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__asm__ volatile("pushfq; popq %0; cli" : "=r"(flags) : : "memory");
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return flags;
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}
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void arch_irq_restore(uint64_t flags)
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{
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if ((flags & (1ull << 9)) != 0) {
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__asm__ volatile("sti" : : : "memory");
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}
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}
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int irq_register(uint8_t irq, irq_handler_t handler, void *data)
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{
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uint64_t flags;
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if (irq >= IRQ_COUNT || handler == 0) {
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return -EINVAL;
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}
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flags = arch_irq_save();
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if (irq_actions[irq].handler != 0) {
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arch_irq_restore(flags);
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return -EBUSY;
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}
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irq_actions[irq].handler = handler;
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irq_actions[irq].data = data;
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arch_irq_restore(flags);
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return 0;
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}
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static void timer_irq_handler(uint8_t irq, void *data)
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{
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(void)irq;
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(void)data;
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timer_tick();
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}
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void handle_irq(struct trap_frame *frame)
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{
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uint64_t irq = frame->vector - IRQ_BASE;
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struct irq_action *action;
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if (irq < IRQ_COUNT) {
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action = &irq_actions[irq];
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if (action->handler != 0) {
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action->handler((uint8_t)irq, action->data);
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pic_send_eoi((uint8_t)irq);
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return;
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}
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}
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early_log_puts("unexpected irq=");
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early_log_u64_decimal(irq);
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early_log_puts("\n");
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pic_send_eoi((uint8_t)irq);
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}
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void arch_timer_init(void)
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{
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pic_remap();
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pic_mask_all_except_timer();
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if (irq_register(IRQ_TIMER, timer_irq_handler, 0) != 0) {
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panic("timer irq registration failed");
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}
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pit_init();
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early_log_puts("timer initialized\n");
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arch_irq_restore(1ull << 9);
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}
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