[PATCH 1/1] mtd: eLBC NAND: fixes subpage write support

[PATCH 1/1] mtd: eLBC NAND: fixes subpage write support

[Pekon Gupta]

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.

CC: <stable@vger.kernel.org> # 3.10.x+

Reported-by: Helmut Schaa <helmut.schaa@googlemail.com>
Tested-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Pekon Gupta <pekon@ti.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 ec549cd..545a5c0 100644
--- a/drivers/mtd/nand/fsl_elbc_nand.c
+++ b/drivers/mtd/nand/fsl_elbc_nand.c
@@ -723,6 +723,19 @@ 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;
@@ -761,6 +774,7 @@ 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) ==
-- 
1.8.5.1.163.gd7aced9

Re: [PATCH 1/1] mtd: eLBC NAND: fixes subpage write support

[Scott Wood]

On Tue, 2014-05-06 at 09:41 +0530, Pekon Gupta wrote:
> 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.
> 
> CC: <stable@vger.kernel.org> # 3.10.x+
> 
> Reported-by: Helmut Schaa <helmut.schaa@googlemail.com>
> Tested-by: Helmut Schaa <helmut.schaa@googlemail.com>
> Signed-off-by: Pekon Gupta <pekon@ti.com>
> ---
>  drivers/mtd/nand/fsl_elbc_nand.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)

Reviewed-by: Scott Wood <scottwood@freescale.com>

-Scott

Re: [PATCH 1/1] mtd: eLBC NAND: fixes subpage write support

[Brian Norris]

On Wed, May 07, 2014 at 06:22:53PM -0500, Scott Wood wrote:
> On Tue, 2014-05-06 at 09:41 +0530, Pekon Gupta wrote:
> > 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.
> > 
> > CC: <stable@vger.kernel.org> # 3.10.x+
> > 
> > Reported-by: Helmut Schaa <helmut.schaa@googlemail.com>
> > Tested-by: Helmut Schaa <helmut.schaa@googlemail.com>
> > Signed-off-by: Pekon Gupta <pekon@ti.com>
> > ---
> >  drivers/mtd/nand/fsl_elbc_nand.c | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> 
> Reviewed-by: Scott Wood <scottwood@freescale.com>

Pushed to l2-mtd. Thanks!

Brian