ide-pmac: PIO mode setup fixes (take 3)

* Add { 0, 0 } entry to {kauai,shasta}_pio_timings[] so kauai_lookup_timing()
  always returns a valid PIO timing (fixes PIO timing not being set for devices
  with minimum PIO cycle <= 120ns).

* Add setting transfer mode on the device to pmac_ide_set_pio_mode().

* Fix pmac_ide_set_pio() to always program chipset for given PIO timing instead
  of only when the device we want to program PIO timing for is the currently
  selected one.

* Now that pmac_ide_set_pio() is fixed there is no need to set transfer mode
  on the device and program chipset for PIO in pmac_ide_tune_chipset()
  (returning 0 == success is not entirely correct but is OK for now since
  the upper layers are only checking ->speedproc return value for DMA modes).

v2:
* s/speed/XFER_PIO_0 + pio/ in pmac_ide_set_pio_mode() so it actually compiles.

* Removal of kauai_lookup_timing() return value checking went to separate patch.

v3:
* Use XFER_PIO_0 not XFER_PIO. (Noticed by Ben)

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ppc/pmac.c

@@ -6,6 +6,7 @@
  * for doing DMA.
  *
  *  Copyright (C) 1998-2003 Paul Mackerras & Ben. Herrenschmidt
+ *  Copyright (C)      2007 Bartlomiej Zolnierkiewicz
  *
  *  This program is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU General Public License
@@ -311,7 +312,8 @@ static struct kauai_timing	kauai_pio_timings[] =
 	{ 240	, 0x0800038b },
 	{ 239	, 0x0800030c },
 	{ 180	, 0x05000249 },
-	{ 120	, 0x04000148 }
+	{ 120	, 0x04000148 },
+	{ 0	, 0 },
 };
 
 static struct kauai_timing	kauai_mdma_timings[] =
@@ -351,7 +353,8 @@ static struct kauai_timing	shasta_pio_timings[] =
 	{ 240	, 0x040003cd },
 	{ 239	, 0x040003cd },
 	{ 180	, 0x0400028b },
-	{ 120	, 0x0400010a }
+	{ 120	, 0x0400010a },
+	{ 0	, 0 },
 };
 
 static struct kauai_timing	shasta_mdma_timings[] =
@@ -695,7 +698,9 @@ pmac_ide_set_pio_mode(ide_drive_t *drive, const u8 pio)
 		drive->name, pio,  *timings);
 #endif	
 
-	if (drive->select.all == HWIF(drive)->INB(IDE_SELECT_REG))
+	if (pmac_ide_do_setfeature(drive, XFER_PIO_0 + pio))
+		return;
+
 	pmac_ide_do_update_timings(drive);
 }
 
@@ -965,7 +970,7 @@ static int pmac_ide_tune_chipset(ide_drive_t *drive, const u8 speed)
 		case XFER_PIO_1:
 		case XFER_PIO_0:
 			pmac_ide_set_pio_mode(drive, speed & 0x07);
-			break;
+			return 0;
 		default:
 			ret = 1;
 	}