ide: add ide_set{_max}_pio() (take 4)

* Add IDE_HFLAG_ABUSE_{PREFETCH,FAST_DEVSEL,DMA_MODES} flags
  and set them in ht6560, cmd640, cmd64x and sc1200 host drivers.

* Add set_pio_mode_abuse() for checking if host driver has a non-standard
  ->tuneproc() implementation and use it in do_special().

* Add ide_set_pio() for setting PIO mode (it uses hwif->pio_mask to find
  the maximum PIO mode supported by the host), also add ide_set_max_pio()
  wrapper for ide_set_pio() to use for auto-tuning.  Convert users of
  ->tuneproc to use ide_set{_max}_pio() where possible.  This leaves only
  do_special(), set_using_pio(), ide_hwif_restore() and ide_set_pio() as
  a direct users of ->tuneproc.

* Remove no longer needed ide_get_best_pio_mode() calls and printk-s
  reporting PIO mode selected from ->tuneproc implementations.

* Rename ->tuneproc hook to ->set_pio_mode and make 'pio' argument const.

* Remove stale comment from ide_config_drive_speed().

v2:
* Fix "ata_" prefix (Noticed by Jeff).

v3:
* Minor cleanups/fixups per Sergei's suggestions.

v4:
* Fix compile problem in drivers/ide/pci/cmd640.c
  (Noticed by Andrew Morton).

* Improve some ->set_pio_mode comments.

Reviewed-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/slc90e66.c b/drivers/ide/pci/slc90e66.c
index cc93535..214d396 100644
--- a/drivers/ide/pci/slc90e66.c
+++ b/drivers/ide/pci/slc90e66.c
@@ -95,9 +95,8 @@
 	spin_unlock_irqrestore(&ide_lock, flags);
 }
 
-static void slc90e66_tune_drive (ide_drive_t *drive, u8 pio)
+static void slc90e66_set_pio_mode(ide_drive_t *drive, const u8 pio)
 {
-	pio = ide_get_best_pio_mode(drive, pio, 4);
 	slc90e66_tune_pio(drive, pio);
 	(void) ide_config_drive_speed(drive, XFER_PIO_0 + pio);
 }
@@ -166,7 +165,7 @@
 		return 0;
 
 	if (ide_use_fast_pio(drive))
-		slc90e66_tune_drive(drive, 255);
+		ide_set_max_pio(drive);
 
 	return -1;
 }
@@ -182,7 +181,7 @@
 		hwif->irq = hwif->channel ? 15 : 14;
 
 	hwif->speedproc = &slc90e66_tune_chipset;
-	hwif->tuneproc	= &slc90e66_tune_drive;
+	hwif->set_pio_mode = &slc90e66_set_pio_mode;
 
 	pci_read_config_byte(hwif->pci_dev, 0x47, &reg47);