mirror of
https://github.com/gbowne1/ClassicOS.git
synced 2026-01-29 16:15:20 -08:00
120 lines
3.3 KiB
C
120 lines
3.3 KiB
C
#include "ata.h"
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#include "io.h"
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#include "print.h"
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#define ATA_TIMEOUT 100000
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static inline void ata_delay(void) {
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/* 400ns delay by reading alternate status */
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inb(ATA_PRIMARY_CTRL);
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inb(ATA_PRIMARY_CTRL);
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inb(ATA_PRIMARY_CTRL);
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inb(ATA_PRIMARY_CTRL);
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}
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bool ata_wait_ready(void) {
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for (int i = 0; i < ATA_TIMEOUT; i++) {
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uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
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/* Must NOT be busy AND must be ready */
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if (!(status & ATA_SR_BSY) && (status & ATA_SR_DRDY))
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return true;
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}
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return false;
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}
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static bool ata_wait(uint8_t mask) {
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for (int i = 0; i < ATA_TIMEOUT; i++) {
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uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
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/* If ERR is set, stop waiting and return failure */
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if (status & ATA_SR_ERR) return false;
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if (!(status & ATA_SR_BSY) && (status & mask))
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return true;
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}
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return false;
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}
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bool ata_init(void) {
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/* Select drive */
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outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, ATA_MASTER);
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ata_delay();
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/* Check if drive exists */
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uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
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if (status == 0xFF || status == 0) return false;
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outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_IDENTIFY);
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ata_delay();
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if (!ata_wait(ATA_SR_DRQ))
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return false;
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uint16_t identify[256];
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for (int i = 0; i < 256; i++)
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identify[i] = inw(ATA_PRIMARY_IO);
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print_string("[ATA] Primary master detected\n");
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return true;
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}
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bool ata_read_sector(uint32_t lba, uint8_t* buffer) {
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if (!buffer) return false;
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/* 1. Wait for drive to be ready for command */
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if (!ata_wait_ready()) return false;
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/* 2. Setup Task File (LBA28) */
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outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
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outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
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outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba));
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outb(ATA_PRIMARY_IO + ATA_REG_LBA1, (uint8_t)(lba >> 8));
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outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16));
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/* 3. Issue Read Command */
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outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_READ_PIO);
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/* 4. Wait for Data Request (DRQ) */
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if (!ata_wait(ATA_SR_DRQ))
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return false;
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/* 5. Transfer data */
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for (int i = 0; i < 256; i++) {
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uint16_t data = inw(ATA_PRIMARY_IO);
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buffer[i * 2] = data & 0xFF;
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buffer[i * 2 + 1] = (data >> 8) & 0xFF;
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}
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ata_delay();
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return true;
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}
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bool ata_write_sector(uint32_t lba, const uint8_t* buffer) {
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if (!buffer) return false;
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/* 1. Wait for drive to be ready for command */
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if (!ata_wait_ready()) return false;
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/* 2. Setup Task File */
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outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
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outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
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outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba));
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outb(ATA_PRIMARY_IO + ATA_REG_LBA1, (uint8_t)(lba >> 8));
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outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16));
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/* 3. Issue Write Command */
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outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_WRITE_PIO);
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/* 4. Wait for drive to request data */
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if (!ata_wait(ATA_SR_DRQ))
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return false;
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/* 5. Transfer data */
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for (int i = 0; i < 256; i++) {
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uint16_t word = buffer[i * 2] | (buffer[i * 2 + 1] << 8);
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outw(ATA_PRIMARY_IO, word);
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}
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ata_delay();
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return true;
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}
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