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/ppc/pmac.c b/drivers/ide/ppc/pmac.c
index 284bb7c..beafdf3 100644
--- a/drivers/ide/ppc/pmac.c
+++ b/drivers/ide/ppc/pmac.c
@@ -411,7 +411,6 @@
 
 static void pmac_ide_setup_dma(pmac_ide_hwif_t *pmif, ide_hwif_t *hwif);
 static int pmac_ide_build_dmatable(ide_drive_t *drive, struct request *rq);
-static void pmac_ide_tuneproc(ide_drive_t *drive, u8 pio);
 static void pmac_ide_selectproc(ide_drive_t *drive);
 static void pmac_ide_kauai_selectproc(ide_drive_t *drive);
 
@@ -615,7 +614,7 @@
  * Old tuning functions (called on hdparm -p), sets up drive PIO timings
  */
 static void
-pmac_ide_tuneproc(ide_drive_t *drive, u8 pio)
+pmac_ide_set_pio_mode(ide_drive_t *drive, const u8 pio)
 {
 	u32 *timings;
 	unsigned accessTicks, recTicks;
@@ -629,7 +628,6 @@
 	/* which drive is it ? */
 	timings = &pmif->timings[drive->select.b.unit & 0x01];
 
-	pio = ide_get_best_pio_mode(drive, pio, 4);
 	cycle_time = ide_pio_cycle_time(drive, pio);
 
 	switch (pmif->kind) {
@@ -966,7 +964,7 @@
 		case XFER_PIO_2:
 		case XFER_PIO_1:
 		case XFER_PIO_0:
-			pmac_ide_tuneproc(drive, speed & 0x07);
+			pmac_ide_set_pio_mode(drive, speed & 0x07);
 			break;
 		default:
 			ret = 1;
@@ -1241,7 +1239,7 @@
 	hwif->drives[0].unmask = 1;
 	hwif->drives[1].unmask = 1;
 	hwif->pio_mask = ATA_PIO4;
-	hwif->tuneproc = pmac_ide_tuneproc;
+	hwif->set_pio_mode = pmac_ide_set_pio_mode;
 	if (pmif->kind == controller_un_ata6
 	    || pmif->kind == controller_k2_ata6
 	    || pmif->kind == controller_sh_ata6)