ide: add ide_dev_is_sata() helper (take 2)

Make the SATA drive detection code from eighty_ninty_three() into inline
ide_dev_is_sata() helper fixing it along the way to be more strict while
checking word 80 for the reserved values...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-iops.c

@@ -615,8 +615,7 @@ u8 eighty_ninty_three (ide_drive_t *drive)
 	if (hwif->cbl != ATA_CBL_PATA80 && !ivb)
 		goto no_80w;
 
-	/* Check for SATA but only if we are ATA5 or higher */
-	if (id->hw_config == 0 && (id->major_rev_num & 0x7FE0))
+	if (ide_dev_is_sata(id))
 		return 1;
 
 	/*

include/linux/ide.h

@@ -1378,6 +1378,19 @@ static inline int ide_dev_has_iordy(struct hd_driveid *id)
 	return ((id->field_valid & 2) && (id->capability & 8)) ? 1 : 0;
 }
 
+static inline int ide_dev_is_sata(struct hd_driveid *id)
+{
+	/*
+	 * See if word 93 is 0 AND drive is at least ATA-5 compatible
+	 * verifying that word 80 by casting it to a signed type --
+	 * this trick allows us to filter out the reserved values of
+	 * 0x0000 and 0xffff along with the earlier ATA revisions...
+	 */
+	if (id->hw_config == 0 && (short)id->major_rev_num >= 0x0020)
+		return 1;
+	return 0;
+}
+
 u8 ide_dump_status(ide_drive_t *, const char *, u8);
 
 typedef struct ide_pio_timings_s {