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/amd74xx.c b/drivers/ide/pci/amd74xx.c
index 9abbde3..1088ba8 100644
--- a/drivers/ide/pci/amd74xx.c
+++ b/drivers/ide/pci/amd74xx.c
@@ -266,16 +266,12 @@
 }
 
 /*
- * amd74xx_tune_drive() is a callback from upper layers for
- * PIO-only tuning.
+ * amd_set_pio_mode() is a callback from upper layers for PIO-only tuning.
  */
 
-static void amd74xx_tune_drive(ide_drive_t *drive, u8 pio)
+static void amd_set_pio_mode(ide_drive_t *drive, const u8 pio)
 {
-	if (pio == 255)
-		pio = ide_get_best_pio_mode(drive, 255, 5);
-
-	amd_set_drive(drive, XFER_PIO_0 + min_t(byte, pio, 5));
+	amd_set_drive(drive, XFER_PIO_0 + pio);
 }
 
 static int amd74xx_ide_dma_check(ide_drive_t *drive)
@@ -283,7 +279,7 @@
 	u8 speed = ide_max_dma_mode(drive);
 
 	if (speed == 0) {
-		amd74xx_tune_drive(drive, 255);
+		ide_set_max_pio(drive);
 		return -1;
 	}
 
@@ -409,7 +405,7 @@
 
 	hwif->autodma = 0;
 
-	hwif->tuneproc = &amd74xx_tune_drive;
+	hwif->set_pio_mode = &amd_set_pio_mode;
 	hwif->speedproc = &amd_set_drive;
 
 	for (i = 0; i < 2; i++) {