[PATCH] 6/8 Backport recent 2.6 IDE updates to 2.4.x

[Erik Andersen <andersen@codepoet.org>]

This patch further refines IDE geometry detection, and takes an
easier path toward detecting when a drive happens to support
things like lba48, making the code more readable and more
consistant.

 -Erik

--
Erik B. Andersen             http://codepoet-consulting.com/
--This message was written using 73% post-consumer electrons--


--- linux/drivers/ide/ide-disk.c.orig	2003-08-16 20:51:58.000000000 -0600
+++ linux/drivers/ide/ide-disk.c	2003-08-16 20:56:49.000000000 -0600
@@ -106,11 +106,6 @@
 {
 	unsigned long lba_sects, chs_sects, head, tail;
 
-	if ((id->command_set_2 & 0x0400) && (id->cfs_enable_2 & 0x0400)) {
-		printk("48-bit Drive: %llu \n", id->lba_capacity_2);
-		return 1;
-	}
-
 	/*
 	 * The ATA spec tells large drives to return
 	 * C/H/S = 16383/16/63 independent of their size.
@@ -1139,11 +1134,29 @@
 	return n;
 }
 
+/*
+ * Bits 10 of command_set_1 and cfs_enable_1 must be equal,
+ * so on non-buggy drives we need test only one.
+ * However, we should also check whether these fields are valid.
+ */
+static inline int idedisk_supports_hpa(const struct hd_driveid *id)
+{
+	return (id->command_set_1 & 0x0400) && (id->cfs_enable_1 & 0x0400);
+}
+
+/*
+ * The same here.
+ */
+static inline int idedisk_supports_lba48(const struct hd_driveid *id)
+{
+	return (id->command_set_2 & 0x0400) && (id->cfs_enable_2 & 0x0400);
+}
+
 static inline void idedisk_check_hpa_lba28(ide_drive_t *drive)
 {
 	unsigned long capacity, set_max;
 
-	capacity = drive->id->lba_capacity;
+	capacity = drive->capacity;
 	set_max = idedisk_read_native_max_address(drive);
 
 	if (set_max <= capacity)
@@ -1158,7 +1171,7 @@
 #ifdef CONFIG_IDEDISK_STROKE
 	set_max = idedisk_set_max_address(drive, set_max);
 	if (set_max) {
-		drive->id->lba_capacity = set_max;
+		drive->capacity = set_max;
 		printk(KERN_INFO "%s: Host Protected Area disabled.\n",
 				 drive->name);
 	}
@@ -1169,7 +1182,7 @@
 {
 	unsigned long long capacity_2, set_max_ext;
 
-	capacity_2 = drive->id->lba_capacity_2;
+	capacity_2 = drive->capacity48;
 	set_max_ext = idedisk_read_native_max_address_ext(drive);
 
 	if (set_max_ext <= capacity_2)
@@ -1184,7 +1197,8 @@
 #ifdef CONFIG_IDEDISK_STROKE
 	set_max_ext = idedisk_set_max_address_ext(drive, set_max_ext);
 	if (set_max_ext) {
-		drive->id->lba_capacity_2 = set_max_ext;
+		drive->capacity48 = set_max_ext;
+		drive->capacity = (unsigned long) set_max_ext;
 		printk(KERN_INFO "%s: Host Protected Area disabled.\n",
 				 drive->name);
 	}
@@ -1212,32 +1226,21 @@
 	 * If this drive supports the Host Protected Area feature set,
 	 * then we may need to change our opinion about the drive's capacity.
 	 */
-	int hpa = (id->command_set_1 & 0x0400) && (id->cfs_enable_1 & 0x0400);
+	int hpa = idedisk_supports_hpa(id);
 
-	if ((id->command_set_2 & 0x0400) && (id->cfs_enable_2 & 0x0400)) {
+	if (idedisk_supports_lba48(id)) {
 		/* drive speaks 48-bit LBA */
-		unsigned long long capacity_2;
-
 		drive->select.b.lba = 1;
+		drive->capacity48 = id->lba_capacity_2;
+		drive->capacity = (unsigned long) drive->capacity48;
 		if (hpa)
 			idedisk_check_hpa_lba48(drive);
-		capacity_2 = id->lba_capacity_2;
-		drive->head		= drive->bios_head = 255;
-		drive->sect		= drive->bios_sect = 63;
-		drive->cyl = (unsigned int) capacity_2 / (drive->head * drive->sect);
-		drive->bios_cyl		= drive->cyl;
-		drive->capacity48	= capacity_2;
-		drive->capacity		= (unsigned long) capacity_2;
 	} else if ((id->capability & 2) && lba_capacity_is_ok(id)) {
 		/* drive speaks 28-bit LBA */
-		unsigned long capacity;
-
 		drive->select.b.lba = 1;
+		drive->capacity = id->lba_capacity;
 		if (hpa)
 			idedisk_check_hpa_lba28(drive);
-		capacity = id->lba_capacity;
-		drive->cyl = capacity / (drive->head * drive->sect);
-		drive->capacity = capacity;
 	} else {
 		/* drive speaks boring old 28-bit CHS */
 		drive->capacity = drive->cyl * drive->head * drive->sect;
@@ -1246,7 +1249,7 @@
 
 static u64 idedisk_capacity (ide_drive_t *drive)
 {
-	if (drive->id->cfs_enable_2 & 0x0400)
+	if (idedisk_supports_lba48(drive->id))
 		return (drive->capacity48 - drive->sect0);
 	return (drive->capacity - drive->sect0);
 }
@@ -1572,7 +1575,7 @@
 	if (HWIF(drive)->addressing)
 		return 0;
 
-	if (!(drive->id->cfs_enable_2 & 0x0400))
+	if (!idedisk_supports_lba48(drive->id))
                 return -EIO;
 	drive->addressing = arg;
 	return 0;
@@ -1696,19 +1699,28 @@
 	 * by correcting bios_cyls:
 	 */
 	capacity = idedisk_capacity (drive);
-	if (!drive->forced_geom && drive->bios_sect && drive->bios_head) {
-		unsigned int cap0 = capacity;	/* truncate to 32 bits */
-		unsigned int cylsz, cyl;
-
-		if (cap0 != capacity)
-			drive->bios_cyl = 65535;
-		else {
-			cylsz = drive->bios_sect * drive->bios_head;
-			cyl = cap0 / cylsz;
-			if (cyl > 65535)
-				cyl = 65535;
-			if (cyl > drive->bios_cyl)
-				drive->bios_cyl = cyl;
+	if (!drive->forced_geom) {
+
+		if (idedisk_supports_lba48(drive->id)) {
+			/* compatibility */
+			drive->bios_sect = 63;
+			drive->bios_head = 255;
+		}
+
+		if (drive->bios_sect && drive->bios_head) {
+			unsigned int cap0 = capacity; /* truncate to 32 bits */
+			unsigned int cylsz, cyl;
+
+			if (cap0 != capacity)
+				drive->bios_cyl = 65535;
+			else {
+				cylsz = drive->bios_sect * drive->bios_head;
+				cyl = cap0 / cylsz;
+				if (cyl > 65535)
+					cyl = 65535;
+				if (cyl > drive->bios_cyl)
+					drive->bios_cyl = cyl;
+			}
 		}
 	}
 	printk(KERN_INFO "%s: %llu sectors (%llu MB)",