PATCH: add drive_to_key functions

[Alan Cox <alan@redhat.com>]

Clear new remove field
Clear pci_dev field on init
Add functions that allow us to keep persistent (reasonably so anyway) keys
	not pointers to drive objects in the /proc file. Worst case is you
	reload the driver 64K times and get the new data not an error.
Clean up ide_system_bus_speed docs


diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.8-rc3/drivers/ide/ide.c linux-2.6.8-rc3/drivers/ide/ide.c
--- linux.vanilla-2.6.8-rc3/drivers/ide/ide.c	2004-08-09 15:51:00.000000000 +0100
+++ linux-2.6.8-rc3/drivers/ide/ide.c	2004-08-12 17:55:05.000000000 +0100
@@ -219,12 +219,15 @@
 	hwif->name[3]	= '0' + index;
 
 	hwif->bus_state	= BUSSTATE_ON;
-
+	
 	hwif->atapi_dma = 0;		/* disable all atapi dma */ 
 	hwif->ultra_mask = 0x80;	/* disable all ultra */
 	hwif->mwdma_mask = 0x80;	/* disable all mwdma */
 	hwif->swdma_mask = 0x80;	/* disable all swdma */
 
+	hwif->pci_dev = NULL;
+	hwif->remove = NULL;
+	
 	sema_init(&hwif->gendev_rel_sem, 0);
 
 	default_hwif_iops(hwif);
@@ -321,12 +324,67 @@
 }
 
 /*
- * ide_system_bus_speed() returns what we think is the system VESA/PCI
- * bus speed (in MHz).  This is used for calculating interface PIO timings.
- * The default is 40 for known PCI systems, 50 otherwise.
- * The "idebus=xx" parameter can be used to override this value.
- * The actual value to be used is computed/displayed the first time through.
+ *	ide_drive_from_key	-	turn key into drive
+ *	@kval: persistent key
+ *
+ *	Convert a key into a drive. Currently the key is packed as
+ *	[keyval] << 16 | hwif << 8 | drive_num. Caller must hold 
+ *	ide_settings_sem for the duration of the returned reference
+ */
+
+ide_drive_t *ide_drive_from_key(void *kval)
+{
+	unsigned long key = (unsigned long) kval;
+	int idx = (key >> 8) & 0xFF;
+	int drive = key & 3;
+	ide_hwif_t *hwif = &ide_hwifs[idx];
+	ide_drive_t *ret;
+	
+	key >>= 16;
+
+	if(hwif->configured == 0 || hwif->present == 0 || hwif->drives[drive].dead || hwif->key != key)
+		ret = NULL;
+	else
+		ret = &ide_hwifs[idx].drives[drive];
+		
+	return ret;
+}
+
+EXPORT_SYMBOL_GPL(ide_drive_from_key);
+
+/*
+ *	ide_drive_to_key	-	turn drive to persistent key
+ *	@drive: drive to use
+ *
+ *	Convert drive into a key. Currently the key is packed as
+ *	[keyval] << 16 | hwif << 8 | drive_num. Caller must hold 
+ *	ide_settings_sem for the duration of the returned reference
  */
+
+void *ide_drive_to_key(ide_drive_t *drive)
+{
+	ide_hwif_t *hwif = HWIF(drive);
+	unsigned long val;
+	
+	val = (hwif->index << 8) | (hwif->key << 16) | drive->select.b.unit;
+	return (void *)val;
+}
+
+EXPORT_SYMBOL_GPL(ide_drive_to_key);
+		
+/**
+ *	ide_system_bus_speed	-	guess bus speed
+ *
+ *	ide_system_bus_speed() returns what we think is the system VESA/PCI
+ *	bus speed (in MHz).  This is used for calculating interface PIO timings.
+ *	The default is 40 for known PCI systems, 50 otherwise.
+ *	The "idebus=xx" parameter can be used to override this value.
+ *	The actual value to be used is computed/displayed the first time
+ *	through. Drivers should only use this as a last resort.
+ *
+ *	Returns a guessed speed in Mhz
+ */
+
 int ide_system_bus_speed (void)
 {
 	if (!system_bus_speed) {

Signed-off-by: Alan Cox <alan@redhat.com>