Files
mop3/kernel/platform/i386_pc/sys/pic.c
2025-12-10 01:33:51 +01:00

137 lines
3.3 KiB
C

/*
Copyright 2025 Kamil Kowalczyk
Redistribution and use in source and binary forms, with or
without modification, are permitted provided that the following
conditions are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
“AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <libk/types.h>
#include <sys/pic.h>
#include <sys/ioport.h>
#include <sys/isr.h>
#define PIC1 0x20
#define PIC2 0xA0
#define PIC1_CMD PIC1
#define PIC1_DATA (PIC1 + 1)
#define PIC2_CMD PIC2
#define PIC2_DATA (PIC2 + 1)
#define PIC_EOI 0x20
#define ICW1_ICW4 0x01
#define ICW1_SINGLE 0x02
#define ICW1_INTVL4 0x04
#define ICW1_LEVEL 0x08
#define ICW1_INIT 0x10
#define ICW4_8086 0x01
#define ICW4_AUTO 0x02
#define ICW4_BUFSLAVE 0x08
#define ICW4_BUFMASER 0x0C
#define ICW4_SFNM 0x10
#define CASCADE_IRQ 2
static void pic_mask_all(void) {
ioport_out8(PIC1_DATA, 0xFF);
ioport_wait();
ioport_out8(PIC2_DATA, 0xFF);
ioport_wait();
}
void pic_init(void) {
// remap & disable
ioport_out8(PIC1_CMD, ICW1_INIT | ICW1_ICW4);
ioport_wait();
ioport_out8(PIC2_CMD, ICW1_INIT | ICW1_ICW4);
ioport_wait();
ioport_out8(PIC1_DATA, 0x20);
ioport_wait();
ioport_out8(PIC2_DATA, 0x28);
ioport_wait();
ioport_out8(PIC1_DATA, 1<<CASCADE_IRQ);
ioport_wait();
ioport_out8(PIC2_DATA, 2);
ioport_wait();
ioport_out8(PIC1_DATA, ICW4_8086);
ioport_wait();
ioport_out8(PIC2_DATA, ICW4_8086);
ioport_wait();
pic_mask_all();
}
void pic_unmask_irq(uint8_t irq) {
uint16_t port;
uint8_t value;
irq -= 0x20;
if (irq < 8) {
port = PIC1_DATA;
} else {
port = PIC2_DATA;
irq -= 8;
}
value = ioport_in8(port) & ~(1<<irq);
ioport_out8(port, value);
}
void pic_mask_irq(uint8_t irq) {
uint16_t port;
uint8_t value;
irq -= 0x20;
if (irq < 8) {
port = PIC1_DATA;
} else {
port = PIC2_DATA;
irq -= 8;
}
value = ioport_in8(port) | (1<<irq);
ioport_out8(port, value);
}
void pic_fini(uint8_t trap) {
if (trap >= 40) {
ioport_out8(PIC2_CMD, PIC_EOI);
ioport_wait();
}
ioport_out8(PIC1_CMD, PIC_EOI);
ioport_wait();
}