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/ide-io.c b/drivers/ide/ide-io.c
index aa9f5f0..9560a8f 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -201,8 +201,7 @@
 		return do_rw_taskfile(drive, args);
 
 	case idedisk_pm_restore_pio:	/* Resume step 1 (restore PIO) */
-		if (drive->hwif->tuneproc != NULL)
-			drive->hwif->tuneproc(drive, 255);
+		ide_set_max_pio(drive);
 		/*
 		 * skip idedisk_pm_idle for ATAPI devices
 		 */
@@ -788,6 +787,30 @@
 	return ide_started;
 }
 
+/*
+ * handle HDIO_SET_PIO_MODE ioctl abusers here, eventually it will go away
+ */
+static int set_pio_mode_abuse(ide_hwif_t *hwif, u8 req_pio)
+{
+	switch (req_pio) {
+	case 202:
+	case 201:
+	case 200:
+	case 102:
+	case 101:
+	case 100:
+		return (hwif->host_flags & IDE_HFLAG_ABUSE_DMA_MODES) ? 1 : 0;
+	case 9:
+	case 8:
+		return (hwif->host_flags & IDE_HFLAG_ABUSE_PREFETCH) ? 1 : 0;
+	case 7:
+	case 6:
+		return (hwif->host_flags & IDE_HFLAG_ABUSE_FAST_DEVSEL) ? 1 : 0;
+	default:
+		return 0;
+	}
+}
+
 /**
  *	do_special		-	issue some special commands
  *	@drive: drive the command is for
@@ -805,9 +828,17 @@
 	printk("%s: do_special: 0x%02x\n", drive->name, s->all);
 #endif
 	if (s->b.set_tune) {
+		ide_hwif_t *hwif = drive->hwif;
+		u8 req_pio = drive->tune_req;
+
 		s->b.set_tune = 0;
-		if (HWIF(drive)->tuneproc != NULL)
-			HWIF(drive)->tuneproc(drive, drive->tune_req);
+
+		if (set_pio_mode_abuse(drive->hwif, req_pio)) {
+			if (hwif->set_pio_mode)
+				hwif->set_pio_mode(drive, req_pio);
+		} else
+			ide_set_pio(drive, req_pio);
+
 		return ide_stopped;
 	} else {
 		if (drive->media == ide_disk)