[PATCH] ide: Allow IDE interface to specify its not capable of 32-bit operations

In some embedded systems the IDE hardware interface may only support 16-bit
or smaller accesses. Allow the interface to specify if this is the case
and don't allow the drive or user to override the setting.

Signed-off-by: Kumar Gala <[e-mail]>
Acked-by: Bartlomiej Zolnierkiewicz <[e-mail]>
Cc: Alan Cox <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/ide/ide-disk.c

···
 		ide_dma_verbose(drive);
 	printk("\n");
 
-	drive->no_io_32bit = id->dword_io ? 1 : 0;
-
 	/* write cache enabled? */
 	if ((id->csfo & 1) || (id->cfs_enable_1 & (1 << 5)))
 		drive->wcache = 1;

drivers/ide/ide-probe.c

···
 			}
 		}
 	}
+
+	for (unit = 0; unit < MAX_DRIVES; ++unit) {
+		ide_drive_t *drive = &hwif->drives[unit];
+
+		if (hwif->no_io_32bit)
+			drive->no_io_32bit = 1;
+		else
+			drive->no_io_32bit = drive->id->dword_io ? 1 : 0;
+	}
 }
 
 static int hwif_init(ide_hwif_t *hwif);

include/linux/ide.h

···
 	unsigned	no_dsc     : 1;	/* 0 default, 1 dsc_overlap disabled */
 	unsigned	auto_poll  : 1; /* supports nop auto-poll */
 	unsigned	sg_mapped  : 1;	/* sg_table and sg_nents are ready */
+	unsigned	no_io_32bit : 1; /* 1 = can not do 32-bit IO ops */
 
 	struct device	gendev;
 	struct completion gendev_rel_comp; /* To deal with device release() */