disk: implement ata_read

include/disk.h

@@ -11,5 +11,6 @@ typedef struct {
 
 void get_disk_info(disk_info *info);
 int ide_check_disk_present();
+uint8_t ata_read(uint8_t *buffer, uint32_t lba);
 
 #endif

include/utils.h

@@ -5,5 +5,8 @@
 uint8 inportb(uint16 _port);
 void outportb(uint16 _port, uint8 _data);
 
+#define inb inportb
+#define outb outportb
+
 #endif
 

src/disk.c

@@ -31,6 +31,8 @@ unsigned short ide_read_data() {
     return data;
 }
 
+#define inw ide_read_data
+
 unsigned char ide_read_status() {
     unsigned char status;
     __asm__ __volatile__("inb %1, %0" : "=a" (status) : "d" (IDE_STATUS));
@@ -129,3 +131,44 @@ int ide_check_disk_present() {
 
     return 0; // No disk present
 }
+
+void ata_400ns_delay()
+{
+	for(int i = 0; i < 4; i++)
+		inb(0x1FC);
+}
+
+//polling
+//just waiting for the drive to be ready to transfer data
+void ata_poll()
+{
+	while(1)
+	{
+		uint8_t status = inportb(0x1F7);
+		if(!(status & STATUS_BUSY) && (status & STATUS_DRQ))
+			break;
+	}
+}
+
+//https://wiki.osdev.org/ATA_PIO_Mode
+//x86 directions section
+uint8_t ata_read(uint8_t *buffer, uint32_t lba)
+{
+	outb(0x1F6, 0xE0 | ((lba >> 24) & 0x0F));
+	outb(0x1F1, 0x00);//TODO: this is probably ignored so could be removed maybe?
+	outb(0x1F2, 1);//1 is sector count, how many sectors are we reading
+	outb(0x1F3, (unsigned char) lba);
+	outb(0x1F4, (unsigned char)(lba >> 8));
+	outb(0x1F5, (unsigned char)(lba >> 16));
+	outb(0x1F7, 0x20); //Send the "READ SECTORS" command
+	//TODO: here we do the polling yo
+	ata_poll();
+	for(int i = 0; i < 256; i++)
+	{
+		uint16_t data = inw(0x1F0);
+		*(uint16_t*)(buffer+i*2) = data;
+		//printf("data: %X\n", data);
+	}
+	//TODO: give the drive 400ns delay to reset DRQ
+	ata_400ns_delay();
+}

src/kernel.c

@@ -17,15 +17,20 @@ void kmain()
 
 	char yooo[256] = "heheh";
 	printf("test string: %s\n", yooo);
-
-	//printf("checking for disk...\n");
-	//int disk_present = ide_check_disk_present();
-	//printf("we got the result, it's %X\n", disk_present);
+	printf("%X %X %X", 0x11, 0xA, 0xFEE1DEAD);
 
 	disk_info info;
 	get_disk_info(&info);
 	printf("CYL HEAD SECT: %X %X %X\n", info.cylinders, info.heads, info.sectors);
 
+	uint8_t buffer[512];
+	ata_read(buffer, 0x0);
+
+	for(int i = 0; i < sizeof(buffer); i++)
+	{
+		printf("%X ", buffer[i]);
+	}
+
 	while(1)
 	{
 		if(inportb(0x64) & 0x1)