mtd: mxc_nand: fix OOB accesses on i.MX27

The OOB handling in the mxc_nand driver is broken for v1 type
controllers (i.MX27/31) with 512 byte page size. This perhaps
did not show up because ubi does not use OOB.
Update the driver to always read/write a whole page even if
only OOB is requested. With this patch the driver passes the
mtd_oobtest on i.MX27 with 512 byte page size. Also tested
with 2048 byte page size and on i.MX35 (v2 type controller)
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/mxc_nand.c

@@ -623,8 +623,7 @@ static void mxc_nand_command(struct mtd_info *mtd, unsigned command,
 		else
 			host->buf_start = column + mtd->writesize;
 
-		if (mtd->writesize > 512)
-			command = NAND_CMD_READ0; /* only READ0 is valid */
+		command = NAND_CMD_READ0; /* only READ0 is valid */
 
 		send_cmd(host, command, false);
 		mxc_do_addr_cycle(mtd, column, page_addr);
@@ -639,31 +638,11 @@ static void mxc_nand_command(struct mtd_info *mtd, unsigned command,
 		break;
 
 	case NAND_CMD_SEQIN:
-		if (column >= mtd->writesize) {
-			/*
-			 * FIXME: before send SEQIN command for write OOB,
-			 * We must read one page out.
-			 * For K9F1GXX has no READ1 command to set current HW
-			 * pointer to spare area, we must write the whole page
-			 * including OOB together.
-			 */
-			if (mtd->writesize > 512)
-				/* call ourself to read a page */
-				mxc_nand_command(mtd, NAND_CMD_READ0, 0,
-						page_addr);
-
-			host->buf_start = column;
-
-			/* Set program pointer to spare region */
-			if (mtd->writesize == 512)
-				send_cmd(host, NAND_CMD_READOOB, false);
-		} else {
-			host->buf_start = column;
+		if (column >= mtd->writesize)
+			/* call ourself to read a page */
+			mxc_nand_command(mtd, NAND_CMD_READ0, 0, page_addr);
 
-			/* Set program pointer to page start */
-			if (mtd->writesize == 512)
-				send_cmd(host, NAND_CMD_READ0, false);
-		}
+		host->buf_start = column;
 
 		send_cmd(host, command, false);
 		mxc_do_addr_cycle(mtd, column, page_addr);