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

kernel/ata.c

@@ -1,119 +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);
-}
-
-bool ata_wait_ready(void) {
-    for (int i = 0; i < ATA_TIMEOUT; i++) {
-        uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
-        /* Must NOT be busy AND must be ready */
-        if (!(status & ATA_SR_BSY) && (status & ATA_SR_DRDY))
-            return true;
-    }
-    return false;
-}
-
-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 ERR is set, stop waiting and return failure */
-        if (status & ATA_SR_ERR) return false;
-        
-        if (!(status & ATA_SR_BSY) && (status & mask))
-            return true;
-    }
-    return false;
-}
-
-bool ata_init(void) {
-    /* Select drive */
-    outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, ATA_MASTER);
-    ata_delay();
-
-    /* Check if drive exists */
-    uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
-    if (status == 0xFF || status == 0) return false;
-
-    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_IDENTIFY);
-    ata_delay();
-
-    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;
-
-    /* 1. Wait for drive to be ready for command */
-    if (!ata_wait_ready()) return false;
-
-    /* 2. Setup Task File (LBA28) */
-    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));
-    
-    /* 3. Issue Read Command */
-    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_READ_PIO);
-
-    /* 4. Wait for Data Request (DRQ) */
-    if (!ata_wait(ATA_SR_DRQ))
-        return false;
-
-    /* 5. Transfer data */
-    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) & 0xFF;
-    }
-
-    ata_delay();
-    return true;
-}
-
-bool ata_write_sector(uint32_t lba, const uint8_t* buffer) {
-    if (!buffer) return false;
-
-    /* 1. Wait for drive to be ready for command */
-    if (!ata_wait_ready()) return false;
-
-    /* 2. Setup Task File */
-    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));
-    
-    /* 3. Issue Write Command */
-    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_WRITE_PIO);
-
-    /* 4. Wait for drive to request data */
-    if (!ata_wait(ATA_SR_DRQ))
-        return false;
-
-    /* 5. Transfer data */
-    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;
-}

kernel/ata.h

@@ -32,13 +32,12 @@
 #define ATA_SR_ERR         0x01
 
 /* Drive select */
-#define ATA_MASTER         0xA0
-#define ATA_SLAVE          0xB0
+#define ATA_MASTER         0x00
+#define ATA_SLAVE          0x10
 
 /* Public API */
 bool ata_init(void);
 bool ata_read_sector(uint32_t lba, uint8_t* buffer);
 bool ata_write_sector(uint32_t lba, const uint8_t* buffer);
-bool ata_wait_ready(void);
 
 #endif