ide: remove ide_auto_reduce_xfer()

While at it:

* Remove needless '!drive->crc_count' check.
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-iops.c

@@ -612,33 +612,6 @@ u8 eighty_ninty_three (ide_drive_t *drive)
 	return 0;
 }
 
-#ifdef CONFIG_BLK_DEV_IDEDMA
-static u8 ide_auto_reduce_xfer (ide_drive_t *drive)
-{
-	if (!drive->crc_count)
-		return drive->current_speed;
-	drive->crc_count = 0;
-
-	switch(drive->current_speed) {
-		case XFER_UDMA_7:	return XFER_UDMA_6;
-		case XFER_UDMA_6:	return XFER_UDMA_5;
-		case XFER_UDMA_5:	return XFER_UDMA_4;
-		case XFER_UDMA_4:	return XFER_UDMA_3;
-		case XFER_UDMA_3:	return XFER_UDMA_2;
-		case XFER_UDMA_2:	return XFER_UDMA_1;
-		case XFER_UDMA_1:	return XFER_UDMA_0;
-			/*
-			 * OOPS we do not goto non Ultra DMA modes
-			 * without iCRC's available we force
-			 * the system to PIO and make the user
-			 * invoke the ATA-1 ATA-2 DMA modes.
-			 */
-		case XFER_UDMA_0:
-		default:		return XFER_PIO_4;
-	}
-}
-#endif /* CONFIG_BLK_DEV_IDEDMA */
-
 int ide_driveid_update(ide_drive_t *drive)
 {
 	ide_hwif_t *hwif = drive->hwif;
@@ -968,8 +941,20 @@ static ide_startstop_t reset_pollfunc (ide_drive_t *drive)
 static void check_dma_crc(ide_drive_t *drive)
 {
 #ifdef CONFIG_BLK_DEV_IDEDMA
+	u8 mode;
+
 	ide_dma_off_quietly(drive);
-	ide_set_xfer_rate(drive, ide_auto_reduce_xfer(drive));
+	drive->crc_count = 0;
+	mode = drive->current_speed;
+	/*
+	 * Don't try non Ultra-DMA modes without iCRC's.  Force the
+	 * device to PIO and make the user enable SWDMA/MWDMA modes.
+	 */
+	if (mode > XFER_UDMA_0 && mode <= XFER_UDMA_7)
+		mode--;
+	else
+		mode = XFER_PIO_4;
+	ide_set_xfer_rate(drive, mode);
 	if (drive->current_speed >= XFER_SW_DMA_0)
 		ide_dma_on(drive);
 #endif