[3.13.y.z extended stable] Patch "mtd: eLBC NAND: fix subpage write support" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    mtd: eLBC NAND: fix subpage write support

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.5.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From c80c25a0a54f6b9e0641d3538c45689b5d4cfbce Mon Sep 17 00:00:00 2001
From: Pekon Gupta <pekon at ti.com>
Date: Tue, 6 May 2014 09:41:32 +0530
Subject: mtd: eLBC NAND: fix subpage write support

commit f034d87def51f026b735d1e2877e9387011b2ba3 upstream.

As subpage write is enabled by default for all drivers, nand_write_subpage_hwecc
causes a crash if the driver did not register ecc->hwctl or ecc->calculate.
This behavior was introduced in
   commit 837a6ba4f3b6d23026674e6af6b6849a4634fff9
   "mtd: nand: subpage write support for hardware based ECC schemes".

This fixes a crash by emulating subpage write support by padding sub-page data
with 0xff on either sides to make it full page compatible.

Reported-by: Helmut Schaa <helmut.schaa at googlemail.com>
Tested-by: Helmut Schaa <helmut.schaa at googlemail.com>
Signed-off-by: Pekon Gupta <pekon at ti.com>
Reviewed-by: Scott Wood <scottwood at freescale.com>
Signed-off-by: Brian Norris <computersforpeace at gmail.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/mtd/nand/fsl_elbc_nand.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/mtd/nand/fsl_elbc_nand.c b/drivers/mtd/nand/fsl_elbc_nand.c
index c966fc7..6ce1fd2 100644
--- a/drivers/mtd/nand/fsl_elbc_nand.c
+++ b/drivers/mtd/nand/fsl_elbc_nand.c
@@ -724,6 +724,19 @@ static int fsl_elbc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
 	return 0;
 }

+/* ECC will be calculated automatically, and errors will be detected in
+ * waitfunc.
+ */
+static int fsl_elbc_write_subpage(struct mtd_info *mtd, struct nand_chip *chip,
+				uint32_t offset, uint32_t data_len,
+				const uint8_t *buf, int oob_required)
+{
+	fsl_elbc_write_buf(mtd, buf, mtd->writesize);
+	fsl_elbc_write_buf(mtd, chip->oob_poi, mtd->oobsize);
+
+	return 0;
+}
+
 static int fsl_elbc_chip_init(struct fsl_elbc_mtd *priv)
 {
 	struct fsl_lbc_ctrl *ctrl = priv->ctrl;
@@ -762,6 +775,7 @@ static int fsl_elbc_chip_init(struct fsl_elbc_mtd *priv)

 	chip->ecc.read_page = fsl_elbc_read_page;
 	chip->ecc.write_page = fsl_elbc_write_page;
+	chip->ecc.write_subpage = fsl_elbc_write_subpage;

 	/* If CS Base Register selects full hardware ECC then use it */
 	if ((in_be32(&lbc->bank[priv->bank].br) & BR_DECC) ==
--
1.9.1