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/legacy/ht6560b.c b/drivers/ide/legacy/ht6560b.c
index bfaa202..2e5a9cc 100644
--- a/drivers/ide/legacy/ht6560b.c
+++ b/drivers/ide/legacy/ht6560b.c
@@ -199,7 +199,7 @@
 	return 1;
 }
 
-static u8 ht_pio2timings(ide_drive_t *drive, u8 pio)
+static u8 ht_pio2timings(ide_drive_t *drive, const u8 pio)
 {
 	int active_time, recovery_time;
 	int active_cycles, recovery_cycles;
@@ -208,7 +208,6 @@
         if (pio) {
 		unsigned int cycle_time;
 
-		pio = ide_get_best_pio_mode(drive, pio, 5);
 		cycle_time = ide_pio_cycle_time(drive, pio);
 
 		/*
@@ -277,7 +276,7 @@
 #endif
 }
 
-static void tune_ht6560b (ide_drive_t *drive, u8 pio)
+static void ht6560b_set_pio_mode(ide_drive_t *drive, const u8 pio)
 {
 	unsigned long flags;
 	u8 timing;
@@ -333,15 +332,17 @@
 
 	hwif->chipset = ide_ht6560b;
 	hwif->selectproc = &ht6560b_selectproc;
+	hwif->host_flags = IDE_HFLAG_ABUSE_PREFETCH;
 	hwif->pio_mask = ATA_PIO5;
-	hwif->tuneproc = &tune_ht6560b;
+	hwif->set_pio_mode = &ht6560b_set_pio_mode;
 	hwif->serialized = 1;	/* is this needed? */
 	hwif->mate = mate;
 
 	mate->chipset = ide_ht6560b;
 	mate->selectproc = &ht6560b_selectproc;
+	mate->host_flags = IDE_HFLAG_ABUSE_PREFETCH;
 	mate->pio_mask = ATA_PIO5;
-	mate->tuneproc = &tune_ht6560b;
+	mate->set_pio_mode = &ht6560b_set_pio_mode;
 	mate->serialized = 1;	/* is this needed? */
 	mate->mate = hwif;
 	mate->channel = 1;