[PATCH 3.12 076/170] mtd: eLBC NAND: fix subpage write support

Jiri Slaby
2014-07-18T13:33:58Z

From: Pekon Gupta <pekon@ti.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

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@googlemail.com>
Tested-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Pekon Gupta <pekon@ti.com>
Reviewed-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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 20657209a472..c31d183820c5 100644
--- a/drivers/mtd/nand/fsl_elbc_nand.c
+++ b/drivers/mtd/nand/fsl_elbc_nand.c
@@ -725,6 +725,19 @@ 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;
@@ -763,6 +776,7 @@ 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) ==
--
2.0.0