Re-add: ATA PIO driver (w/o paging)

src/drivers/ata.c

@@ -0,0 +1,77 @@
+#include "../libc/stdint.h" 
+#include "../kernel/io.h"
+#include "../libc/stdio.h"
+
+#define ATA_PRIMARY_IO 		0x1F0
+#define ATA_PRIMARY_CTRL 	0x3F6
+#define ATA_CMD_READ_PIO	0x20
+#define ATA_CMD_WRITE_PIO 	0x30
+#define ATA_IDENTIFY 		0xEC
+
+#define ATA_REG_DATA 		0x00
+#define ATA_REG_ERROR 		0x01
+#define ATA_REG_SECCOUNT0 	0x02
+#define ATA_REG_LBA0 		0x03
+#define ATA_REG_LBA1 		0x04
+#define ATA_REG_LBA2 		0x05
+#define ATA_REG_HDDEVSEL 	0x06
+#define ATA_REG_COMMAND 	0x07
+#define ATA_REG_STATUS 		0x07
+
+#define ATA_SR_BSY 		0x80
+#define ATA_SR_DRDY 		0x40
+#define ATA_SR_DRQ 		0x08
+#define ATA_SR_ERR 		0x01
+
+static inline uint16_t inw(uint16_t port) {
+    uint16_t result;
+    asm volatile("inw %1, %0" : "=a"(result) : "dN"(port));
+    return result;
+}
+
+static inline void outw(uint16_t port, uint16_t data) {
+    asm volatile("outw %1, %0" : : "dN"(port), "a"(data));
+}
+
+void ata_wait_bsy() {
+    while (inb(ATA_PRIMARY_IO + ATA_REG_STATUS) & ATA_SR_BSY);
+}
+
+void ata_wait_drq() {
+    while (!(inb(ATA_PRIMARY_IO + ATA_REG_STATUS) & ATA_SR_DRQ));
+}
+
+void ata_select_drive(uint8_t drive) {
+    outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xE0 | (drive << 4));
+}
+
+void ata_read_sector(uint32_t lba, uint8_t* buffer) {
+    ata_wait_bsy();
+    ata_select_drive(0);
+
+    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_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
+
+    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_READ_PIO);
+
+    ata_wait_bsy();
+    ata_wait_drq();
+
+    for (int i = 0; i < 256; i++) {
+        ((uint16_t*)buffer)[i] = inw(ATA_PRIMARY_IO + ATA_REG_DATA);
+    }
+}
+
+// Works only w/o paging
+void test_read_sector() {
+    uint8_t buffer[512];
+    ata_read_sector(0, buffer);
+
+    for (int i = 0; i < 512; i++) {
+        if (i%25==0) puts("\n");
+	printf("%02x ", buffer[i]);
+    }
+}