big chungus

* fix a heap corruption bug
* add qemu support
* add an ATA driver
* add an USTAR read-only file system
* boot from disk instead of floppy
* font rendering
* image rendering
* PCI enumeration
* init script

1 files changed, 158 insertions, 0 deletions

diff --git a/stage3/ata.c b/stage3/ata.c
new file mode 100644
index 0000000..ccfd695
--- /dev/null
+++ b/stage3/ata.c
@@ -0,0 +1,158 @@
+#include "ata.h"
+#include "halt.h"
+#include "heap.h"
+#include "io.h"
+#include "font.h"
+
+#define ATA_IO_DATA 0
+#define ATA_IO_ERR 1
+#define ATA_IO_FEATURES 1
+#define ATA_IO_SECTORS 2
+#define ATA_IO_LBA_LOW 3
+#define ATA_IO_LBA_MID 4
+#define ATA_IO_LBA_HIGH 5
+#define ATA_IO_HEAD 6
+#define ATA_IO_STATUS 7
+#define ATA_IO_COMMAND 7
+
+#define IO_ATA0_DATA 0x1F0
+#define IO_ATA0_CTRL 0x3F6
+
+#define ATA_CMD_IDENTIFY 0xEC
+#define ATA_CMD_READ_SECTORS_EXT 0x24
+
+typedef struct __attribute__((packed)) {
+	bool err : 1;
+	bool idx : 1;
+	bool corr : 1; // corrected data
+	bool drq : 1;  // has data or ready to accept data
+	bool srv : 1;  // overlapped
+	bool df : 1;   // drive fault
+	bool rdy : 1;  // clear if spun down or error
+	bool bsy : 1;  // preparing/busy
+} ata_status;
+
+typedef struct {
+	unsigned int bits : 4;
+	bool doll : 1; 
+	bool one0 : 1;
+	bool lba : 1;
+	bool one1 : 1;
+} __attribute__((packed)) ata_head;
+
+void ata_recv(u16 *buffer)
+{
+	for (;;) {
+		ata_status status = BITCAST(inb(IO_ATA0_DATA + ATA_IO_STATUS), u8, ata_status);
+
+		if (status.err) {
+			u8 err = inb(IO_ATA0_DATA + ATA_IO_ERR);
+
+			const char *errors[] = {
+				"address mark not found\n",
+				"track zero not found\n",
+				"aborted command\n",
+				"media change request\n",
+				"id not found\n",
+				"media changed\n",
+				"uncorrectable data error\n",
+				"bad block detected\n",
+			};
+
+			for (int i = 0; i < 8; i++)
+				if (err & (1 << i))
+					print(errors[i]);
+			
+			panic("ata0-witch error\n");
+		} else if (status.drq)
+			break;
+	}
+
+	for (int i = 0; i < 256; i++)
+		buffer[i] = inw(IO_ATA0_DATA + ATA_IO_DATA);
+}
+
+void ata_delay()
+{
+	for (int i = 0; i < 15; i++)
+		inb(IO_ATA0_DATA + ATA_IO_STATUS);	
+}
+
+void ata_init()
+{
+	u8 floating = inb(IO_ATA0_DATA + ATA_IO_STATUS);
+	if (floating == 0xFF)
+		panic("ata0 floating\n");
+
+	outb(IO_ATA0_DATA + ATA_IO_HEAD, BITCAST(((ata_head) {
+		.bits = 0,
+		.doll = false,
+		.one0 = true,
+		.lba = false,
+		.one1 = true,
+	}), ata_head, u8));
+	ata_delay();
+	outb(IO_ATA0_DATA + ATA_IO_LBA_LOW, 0);
+	outb(IO_ATA0_DATA + ATA_IO_LBA_MID, 0);
+	outb(IO_ATA0_DATA + ATA_IO_LBA_HIGH, 0);
+	outb(IO_ATA0_DATA + ATA_IO_COMMAND, ATA_CMD_IDENTIFY);
+
+	u8 status_byte = inb(IO_ATA0_DATA + ATA_IO_STATUS);
+	if (status_byte == 0)
+		panic("no ata0-witch drive\n");
+
+	while (BITCAST(status_byte, u8, ata_status).bsy)
+		status_byte = inb(IO_ATA0_DATA + ATA_IO_STATUS);
+
+	if (inb(IO_ATA0_DATA + ATA_IO_LBA_MID) != 0 || inb(IO_ATA0_DATA + ATA_IO_LBA_HIGH) != 0)
+		panic("ata0-witch is not ATA\n");
+
+	u16 *idvec = malloc(256 * sizeof *idvec);
+	ata_recv(idvec);
+
+	if (!(idvec[83] & (1 << 10)))
+		panic("ata0-witch does not support LBA48 mode\n");
+
+	// u64 lba48_sectors = *(u64 *) &idvec[100];
+	// print_num(lba48_sectors, 10, 0); print("\n");
+
+	free(idvec);
+}
+
+void ata_read(u64 lba, u16 sectors, void *buffer)
+{
+	outb(IO_ATA0_DATA + ATA_IO_HEAD, BITCAST(((ata_head) {
+		.bits = 0,
+		.doll = false,
+		.one0 = true,
+		.lba = true,
+		.one1 = true,
+	}), ata_head, u8));
+	ata_delay();
+	outb(IO_ATA0_DATA + ATA_IO_SECTORS, sectors >> 8);
+	outb(IO_ATA0_DATA + ATA_IO_LBA_LOW, (lba >> 24) & 0xff);
+	outb(IO_ATA0_DATA + ATA_IO_LBA_MID, (lba >> 32) & 0xff);
+	outb(IO_ATA0_DATA + ATA_IO_LBA_HIGH, (lba >> 40) & 0xff);
+	outb(IO_ATA0_DATA + ATA_IO_SECTORS, sectors & 0xff);
+	outb(IO_ATA0_DATA + ATA_IO_LBA_LOW, lba & 0xff);
+	outb(IO_ATA0_DATA + ATA_IO_LBA_MID, (lba >> 8) & 0xff);
+	outb(IO_ATA0_DATA + ATA_IO_LBA_HIGH, (lba >> 16) & 0xff);
+	outb(IO_ATA0_DATA + ATA_IO_COMMAND, ATA_CMD_READ_SECTORS_EXT);
+
+	for (u16 i = 0; i < sectors; i++)
+		ata_recv(buffer + i*512);
+}
+
+void *ata_read_full(u64 lba, u64 sectors)
+{
+	void *buffer = malloc(512 * sectors);
+
+	for (u64 off = 0; off < sectors; off += 0x10000) {
+		u64 sects = sectors - off;
+		if (sects >= 0x10000)
+			sects = 0;
+		ata_read(lba + off, (u16) sects, buffer + off * 512);
+	}
+
+	return buffer;
+}