# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1323344087 -7200
# Node ID a398bf73fe93d2ba9e8d6de8e1992294cc159b0c
# Parent  178d5a95e6de1afe1d61f28bc79c545b3f8d8523
- added the partition table parsing code
- starting with the filesystem

diff -r 178d5a95e6de -r a398bf73fe93 .hgignore
--- a/.hgignore	Wed Dec 07 17:10:37 2011 +0200
+++ b/.hgignore	Thu Dec 08 13:34:47 2011 +0200
@@ -3,3 +3,4 @@
 \.swp$
 ^kernel.elf$
 ^link.map$
+^disk.img$
diff -r 178d5a95e6de -r a398bf73fe93 src/ata.c
--- a/src/ata.c	Wed Dec 07 17:10:37 2011 +0200
+++ b/src/ata.c	Thu Dec 08 13:34:47 2011 +0200
@@ -78,8 +78,7 @@
 #define MAX_IFACES		2
 #define MAX_DEV			(MAX_IFACES * 2)
 static struct device devices[MAX_DEV];
-
-static int use_irq;
+static int ndev;
 
 /* This serves as a sync point for I/O. While the mutex is held,
  * some process is doing I/O and all the others must wait.
@@ -93,28 +92,32 @@
 
 	interrupt(IRQ_TO_INTR(15), ata_intr);
 
+	ndev = 0;
 	for(i=0; i<MAX_DEV; i++) {
 		int iface = i / MAX_IFACES;
 		int id = i % MAX_IFACES;
 
-		if(identify(devices + i, iface, id) == -1) {
-			devices[i].id = -1;
+		if(identify(devices + ndev, iface, id) == 0) {
+			ndev++;
 		}
 	}
+}
 
-	/* init code done, from now on use the irq sleep/wakeup mechanism */
-	use_irq = 1;
+int ata_num_devices(void)
+{
+	return ndev;
 }
 
 int ata_read_pio(int devno, uint64_t sect, void *buf)
 {
-	int cmd, st, res = -1;
+	int use_irq, cmd, st, res = -1;
 	uint32_t sect_low, sect_high;
 	struct device *dev = devices + devno;
 
 	if(dev->id == -1) {
 		return -1;
 	}
+	use_irq = get_current_proc() != 0;
 
 	if(use_irq) {
 		/* wait for the interface to become available */
diff -r 178d5a95e6de -r a398bf73fe93 src/ata.h
--- a/src/ata.h	Wed Dec 07 17:10:37 2011 +0200
+++ b/src/ata.h	Thu Dec 08 13:34:47 2011 +0200
@@ -3,6 +3,8 @@
 
 void init_ata(void);
 
+int ata_num_devices(void);
+
 int ata_read_pio(int devno, uint64_t sect, void *buf);
 int ata_write_pio(int devno, uint64_t sect, void *buf);
 
diff -r 178d5a95e6de -r a398bf73fe93 src/fs.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/fs.c	Thu Dec 08 13:34:47 2011 +0200
@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include "fs.h"
+#include "ata.h"
+#include "part.h"
+#include "panic.h"
+
+#define PART_TYPE	0xcc
+
+static int find_rootfs(int *dev, struct partition *part);
+
+/* root device & partition */
+static int rdev;
+static struct partition rpart;
+
+void init_fs(void)
+{
+	if(find_rootfs(&rdev, &rpart) == -1) {
+		panic("can't find root filesystem\n");
+	}
+}
+
+static int find_rootfs(int *dev, struct partition *part)
+{
+	int i, num_dev, partid;
+	struct partition *plist, *p;
+
+	num_dev = ata_num_devices();
+	for(i=0; i<num_dev; i++) {
+		plist = p = get_part_list(i);
+
+		partid = 0;
+		while(p) {
+			if(get_part_type(p) == PART_TYPE) {
+				/* found it! */
+				printf("using ata%dp%d\n", i, partid);
+				*dev = i;
+				*part = *p;
+				return 0;
+			}
+			p = p->next;
+			partid++;
+		}
+		free_part_list(plist);
+	}
+	return -1;
+}
diff -r 178d5a95e6de -r a398bf73fe93 src/fs.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/fs.h	Thu Dec 08 13:34:47 2011 +0200
@@ -0,0 +1,6 @@
+#ifndef FS_H_
+#define FS_H_
+
+void init_fs(void);
+
+#endif	/* FS_H_ */
diff -r 178d5a95e6de -r a398bf73fe93 src/main.c
--- a/src/main.c	Wed Dec 07 17:10:37 2011 +0200
+++ b/src/main.c	Thu Dec 08 13:34:47 2011 +0200
@@ -6,6 +6,7 @@
 #include "segm.h"
 #include "intr.h"
 #include "ata.h"
+#include "fs.h"
 #include "rtc.h"
 #include "timer.h"
 #include "mem.h"
@@ -38,6 +39,8 @@
 
 	/* initialize ATA disks */
 	init_ata();
+	/* initialize the filesystem */
+	init_fs();
 
 	/* initialize the timer and RTC */
 	init_timer();
diff -r 178d5a95e6de -r a398bf73fe93 src/part.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/part.c	Thu Dec 08 13:34:47 2011 +0200
@@ -0,0 +1,149 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include "part.h"
+#include "ata.h"
+
+#define PTYPE_EXT		0x5
+#define PTYPE_EXT_LBA	0xf
+
+#define PATTR_ACT_BIT	(1 << 9)
+#define PATTR_PRIM_BIT	(1 << 10)
+
+#define PTYPE(attr)		((attr) & 0xff)
+#define IS_ACT(attr)	((attr) & PATTR_ACT_BIT)
+#define IS_PRIM(attr)	((attr) & PATTR_PRIM_BIT)
+
+#define BOOTSIG_OFFS	510
+#define PTABLE_OFFS		0x1be
+
+#define BOOTSIG			0xaa55
+
+#define IS_MBR			(sidx == 0)
+#define IS_FIRST_EBR	(!IS_MBR && (first_ebr_offs == 0))
+
+struct part_record {
+	uint8_t stat;
+	uint8_t first_head, first_cyl, first_sect;
+	uint8_t type;
+	uint8_t last_head, last_cyl, last_sect;
+	uint32_t first_lba;
+	uint32_t nsect_lba;
+} __attribute__((packed));
+
+
+static uint16_t bootsig(const char *sect);
+
+
+struct partition *get_part_list(int devno)
+{
+	char *sect;
+	struct partition *phead = 0, *ptail = 0;
+	uint32_t sidx = 0;
+	uint32_t first_ebr_offs = 0;
+	int i, num_bootrec = 0;
+
+	sect = malloc(512);
+	assert(sect);
+
+	do {
+		int num_rec;
+		struct part_record *prec;
+
+		if(IS_FIRST_EBR) {
+			first_ebr_offs = sidx;
+		}
+
+		if(ata_read_pio(devno, sidx, sect) == -1) {
+			goto err;
+		}
+		if(bootsig(sect) != BOOTSIG) {
+			printf("invalid/corrupted partition table, sector %lu has no magic\n", (unsigned long)sidx);
+			goto err;
+		}
+		prec = (struct part_record*)(sect + PTABLE_OFFS);
+
+		/* MBR has 4 records, EBRs have 2 */
+		num_rec = IS_MBR ? 4 : 2;
+
+		for(i=0; i<num_rec; i++) {
+			struct partition *pnode;
+
+			/* ignore empty partitions in the MBR, stop if encountered in an EBR */
+			if(prec[i].type == 0) {
+				if(num_bootrec > 0) {
+					sidx = 0;
+					break;
+				}
+				continue;
+			}
+
+			/* ignore extended partitions and setup sector index to read
+			 * the next logical partition afterwards.
+			 */
+			if(prec[i].type == PTYPE_EXT || prec[i].type == PTYPE_EXT_LBA) {
+				/* all EBR start fields are relative to the first EBR offset */
+				sidx = first_ebr_offs + prec[i].first_lba;
+				continue;
+			}
+
+			pnode = malloc(sizeof *pnode);
+			assert(pnode);
+
+			pnode->attr = prec[i].type;
+
+			if(prec[i].stat & 0x80) {
+				pnode->attr |= PATTR_ACT_BIT;
+			}
+			if(IS_MBR) {
+				pnode->attr |= PATTR_PRIM_BIT;
+			}
+			pnode->start_sect = prec[i].first_lba + first_ebr_offs;
+			pnode->size_sect = prec[i].nsect_lba;
+			pnode->next = 0;
+
+			/* append to the list */
+			if(!phead) {
+				phead = ptail = pnode;
+			} else {
+				ptail->next = pnode;
+				ptail = pnode;
+			}
+		}
+
+		num_bootrec++;
+	} while(sidx > 0);
+
+	free(sect);
+	return phead;
+
+err:
+	free(sect);
+	while(phead) {
+		void *tmp = phead;
+		phead = phead->next;
+		free(tmp);
+	}
+	return 0;
+}
+
+void free_part_list(struct partition *plist)
+{
+	while(plist) {
+		struct partition *tmp = plist;
+		plist = plist->next;
+		free(tmp);
+	}
+}
+
+int get_part_type(struct partition *p)
+{
+	return PTYPE(p->attr);
+}
+
+
+static uint16_t bootsig(const char *sect)
+{
+	return *(uint16_t*)(sect + BOOTSIG_OFFS);
+}
+
diff -r 178d5a95e6de -r a398bf73fe93 src/part.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/part.h	Thu Dec 08 13:34:47 2011 +0200
@@ -0,0 +1,20 @@
+#ifndef PART_H_
+#define PART_H_
+
+#include <inttypes.h>
+
+struct partition {
+	uint32_t start_sect;
+	size_t size_sect;
+
+	unsigned int attr;
+
+	struct partition *next;
+};
+
+struct partition *get_part_list(int devno);
+void free_part_list(struct partition *plist);
+
+int get_part_type(struct partition *p);
+
+#endif	/* PART_H_ */