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Update ata.c

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Updated ata.c to include fixed BSY status register
This commit is contained in:
Gregory Kenneth Bowne
2026-01-26 17:16:31 -08:00
committed by Borna Šoštarić
parent 1575c0dd12
commit 769f96acbc
1 changed files with 37 additions and 9 deletions
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46
kernel/ata.c
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@@ -12,9 +12,22 @@ static inline void ata_delay(void) {
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) { static bool ata_wait(uint8_t mask) {
for (int i = 0; i < ATA_TIMEOUT; i++) { for (int i = 0; i < ATA_TIMEOUT; i++) {
uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS); 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)) if (!(status & ATA_SR_BSY) && (status & mask))
return true; return true;
} }
@@ -22,16 +35,17 @@ static bool ata_wait(uint8_t mask) {
} }
bool ata_init(void) { bool ata_init(void) {
outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xA0); // master /* Select drive */
outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, ATA_MASTER);
ata_delay(); 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); outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_IDENTIFY);
ata_delay(); 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)) if (!ata_wait(ATA_SR_DRQ))
return false; return false;
@@ -46,20 +60,28 @@ bool ata_init(void) {
bool ata_read_sector(uint32_t lba, uint8_t* buffer) { bool ata_read_sector(uint32_t lba, uint8_t* buffer) {
if (!buffer) return false; 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_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1); outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba)); 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_LBA1, (uint8_t)(lba >> 8));
outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16)); 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); outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_READ_PIO);
/* 4. Wait for Data Request (DRQ) */
if (!ata_wait(ATA_SR_DRQ)) if (!ata_wait(ATA_SR_DRQ))
return false; return false;
/* 5. Transfer data */
for (int i = 0; i < 256; i++) { for (int i = 0; i < 256; i++) {
uint16_t data = inw(ATA_PRIMARY_IO); uint16_t data = inw(ATA_PRIMARY_IO);
buffer[i * 2] = data & 0xFF; buffer[i * 2] = data & 0xFF;
buffer[i * 2 + 1] = data >> 8; buffer[i * 2 + 1] = (data >> 8) & 0xFF;
} }
ata_delay(); ata_delay();
@@ -69,20 +91,26 @@ bool ata_read_sector(uint32_t lba, uint8_t* buffer) {
bool ata_write_sector(uint32_t lba, const uint8_t* buffer) { bool ata_write_sector(uint32_t lba, const uint8_t* buffer) {
if (!buffer) return false; 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_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1); outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba)); 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_LBA1, (uint8_t)(lba >> 8));
outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16)); 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); outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_WRITE_PIO);
/* 4. Wait for drive to request data */
if (!ata_wait(ATA_SR_DRQ)) if (!ata_wait(ATA_SR_DRQ))
return false; return false;
/* 5. Transfer data */
for (int i = 0; i < 256; i++) { for (int i = 0; i < 256; i++) {
uint16_t word = uint16_t word = buffer[i * 2] | (buffer[i * 2 + 1] << 8);
buffer[i * 2] |
(buffer[i * 2 + 1] << 8);
outw(ATA_PRIMARY_IO, word); outw(ATA_PRIMARY_IO, word);
} }