1 Commits

Author SHA1 Message Date
23cb50a73f Create ata.h
implement the base ata pio mode driver so that the filesystems like fat16, fat32 work. This is the header for that. It will need a iso9660 driver for cdrom etc optical media
2026-01-18 17:44:18 -08:00

View File

@@ -1,91 +0,0 @@
#include "ata.h"
#include "io.h"
#include "print.h"
#define ATA_TIMEOUT 100000
static inline void ata_delay(void) {
/* 400ns delay by reading alternate status */
inb(ATA_PRIMARY_CTRL);
inb(ATA_PRIMARY_CTRL);
inb(ATA_PRIMARY_CTRL);
inb(ATA_PRIMARY_CTRL);
}
static bool ata_wait(uint8_t mask) {
for (int i = 0; i < ATA_TIMEOUT; i++) {
uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
if (!(status & ATA_SR_BSY) && (status & mask))
return true;
}
return false;
}
bool ata_init(void) {
outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xA0); // master
ata_delay();
outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_IDENTIFY);
ata_delay();
uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
if (status == 0)
return false; // no drive
if (!ata_wait(ATA_SR_DRQ))
return false;
uint16_t identify[256];
for (int i = 0; i < 256; i++)
identify[i] = inw(ATA_PRIMARY_IO);
print_string("[ATA] Primary master detected\n");
return true;
}
bool ata_read_sector(uint32_t lba, uint8_t* buffer) {
if (!buffer) return false;
outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba));
outb(ATA_PRIMARY_IO + ATA_REG_LBA1, (uint8_t)(lba >> 8));
outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16));
outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_READ_PIO);
if (!ata_wait(ATA_SR_DRQ))
return false;
for (int i = 0; i < 256; i++) {
uint16_t data = inw(ATA_PRIMARY_IO);
buffer[i * 2] = data & 0xFF;
buffer[i * 2 + 1] = data >> 8;
}
ata_delay();
return true;
}
bool ata_write_sector(uint32_t lba, const uint8_t* buffer) {
if (!buffer) return false;
outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba));
outb(ATA_PRIMARY_IO + ATA_REG_LBA1, (uint8_t)(lba >> 8));
outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16));
outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_WRITE_PIO);
if (!ata_wait(ATA_SR_DRQ))
return false;
for (int i = 0; i < 256; i++) {
uint16_t word =
buffer[i * 2] |
(buffer[i * 2 + 1] << 8);
outw(ATA_PRIMARY_IO, word);
}
ata_delay();
return true;
}