libata-core: Fix the iordy methods

This alone isn't sufficient to save the universe from prehistoric disks
and controllers but it is a first important step. Split off a separate
function to provide a mode filter when controller iordy is not available.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-core.c

@@ -1382,27 +1382,41 @@ unsigned int ata_do_simple_cmd(struct ata_device *dev, u8 cmd)
  
 unsigned int ata_pio_need_iordy(const struct ata_device *adev)
 {
-	int pio;
-	int speed = adev->pio_mode - XFER_PIO_0;
-
-	if (speed < 2)
+	/* Controller doesn't support  IORDY. Probably a pointless check
+	   as the caller should know this */
+	if (adev->ap->flags & ATA_FLAG_NO_IORDY)
 		return 0;
-	if (speed > 2)
+	/* PIO3 and higher it is mandatory */
+	if (adev->pio_mode > XFER_PIO_2)
+		return 1;
+	/* We turn it on when possible */
+	if (ata_id_has_iordy(adev->id))
 		return 1;
+	return 0;
+}
 
-	/* If we have no drive specific rule, then PIO 2 is non IORDY */
+/**
+ *	ata_pio_mask_no_iordy	-	Return the non IORDY mask
+ *	@adev: ATA device
+ *
+ *	Compute the highest mode possible if we are not using iordy. Return
+ *	-1 if no iordy mode is available.
+ */
  
+static u32 ata_pio_mask_no_iordy(const struct ata_device *adev)
+{
+	/* If we have no drive specific rule, then PIO 2 is non IORDY */
 	if (adev->id[ATA_ID_FIELD_VALID] & 2) {	/* EIDE */
-		pio = adev->id[ATA_ID_EIDE_PIO];
+		u16 pio = adev->id[ATA_ID_EIDE_PIO];
 		/* Is the speed faster than the drive allows non IORDY ? */
 		if (pio) {
 			/* This is cycle times not frequency - watch the logic! */
 			if (pio > 240)	/* PIO2 is 240nS per cycle */
-				return 1;
-			return 0;
+				return 3 << ATA_SHIFT_PIO;
+			return 7 << ATA_SHIFT_PIO;
 		}
 	}
-	return 0;
+	return 3 << ATA_SHIFT_PIO;
 }
 
 /**