mtd: nand: teach write_page and write_page_raw return an error code

There is an implemention of hardware ECC write page function which may return an
error indication.
For instance, using Atmel HW PMECC to write one page into a nand flash, the hardware
engine will compute the BCH ecc code for this page. so we need read a the
status register to theck whether the ecc code is generated.
But we cannot assume the status register always can be ready, for example,
incorrect hardware configuration or hardware issue, in such case we need
write_page() to return a error code.

Since the definition of 'write_page' function in struct nand_ecc_ctrl is 'void'.
So this patch will:
  1. add return 'int' value for 'write_page' function.
  2. to be consitent, add return 'int' value for 'write_page_raw' fuctions too.
  3. add code to test the return value, and if negative, indicate an
  error happend when write page with ECC.
  4. fix the compile warning in all impacted nand flash driver.

Note: I couldn't compile-test all of these easily, as some had ARCH dependencies.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/drivers/mtd/nand/cafe_nand.c b/drivers/mtd/nand/cafe_nand.c
index ac0d967ee3f..08248a0a167 100644
--- a/drivers/mtd/nand/cafe_nand.c
+++ b/drivers/mtd/nand/cafe_nand.c
@@ -520,7 +520,7 @@ static struct nand_bbt_descr cafe_bbt_mirror_descr_512 = {
 };
 
 
-static void cafe_nand_write_page_lowlevel(struct mtd_info *mtd,
+static int cafe_nand_write_page_lowlevel(struct mtd_info *mtd,
 					  struct nand_chip *chip,
 					  const uint8_t *buf, int oob_required)
 {
@@ -531,6 +531,8 @@ static void cafe_nand_write_page_lowlevel(struct mtd_info *mtd,
 
 	/* Set up ECC autogeneration */
 	cafe->ctl2 |= (1<<30);
+
+	return 0;
 }
 
 static int cafe_nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
@@ -542,9 +544,12 @@ static int cafe_nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
 	chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page);
 
 	if (unlikely(raw))
-		chip->ecc.write_page_raw(mtd, chip, buf, oob_required);
+		status = chip->ecc.write_page_raw(mtd, chip, buf, oob_required);
 	else
-		chip->ecc.write_page(mtd, chip, buf, oob_required);
+		status = chip->ecc.write_page(mtd, chip, buf, oob_required);
+
+	if (status < 0)
+		return status;
 
 	/*
 	 * Cached progamming disabled for now, Not sure if its worth the