[PATCH] mtd: nand: Disable subpage writes for drivers without ecc->hwctl

[Gupta, Pekon]

>From: Scott Wood [mailto:scottwood at freescale.com]
>>On Fri, 2014-04-11 at 06:35 +0000, Gupta, Pekon wrote:
>> As per [1] and [2], If the subpage is _not_ supported then VID-header offset
>> should be aligned to  PAGE_SIZE boundary. And it has implications on LEB size
>> calculation too. I don't know how it was working earlier but if the earlier
>> UBI images were using 512 as VID Header offset even without subpage
>> Support then it's incorrect configuration.
>
>I believe what was happening before was full page writes with only
>subpage content (the rest left at 0xff).
>
Yes, that is possible, sorry I missed that nand_do_write_ops() does 0xff padding
for non-page aligned writes. In that case replicating fsl_elbc_write_page() for
chip->ecc.write_subpage should also work and maintain backward compatibility.

(not compile tested)
------------------------------------
diff --git a/drivers/mtd/nand/fsl_elbc_nand.c b/drivers/mtd/nand/fsl_elbc_nand.c
index a21252c..cc79ce4 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;
@@ -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) ==

------------------------------------

with regards, pekon