[PATCH v3 4/5] mtd: nand: remove custom 'erased check' implementation

[Boris Brezillon]

Some drivers are manually checking for 'erased pages' while correcting
ECC bytes.
This logic is now done by the core infrastructure, and can thus be removed
from those drivers.

Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
---
 drivers/mtd/nand/davinci_nand.c |  8 --------
 drivers/mtd/nand/diskonchip.c   | 32 ++------------------------------
 drivers/mtd/nand/jz4740_nand.c  | 18 ------------------
 3 files changed, 2 insertions(+), 56 deletions(-)

diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
index 816ef53..0d6adbe 100644
--- a/drivers/mtd/nand/davinci_nand.c
+++ b/drivers/mtd/nand/davinci_nand.c
@@ -316,14 +316,6 @@ static int nand_davinci_correct_4bit(struct mtd_info *mtd,
 	unsigned num_errors, corrected;
 	unsigned long timeo;
 
-	/* All bytes 0xff?  It's an erased page; ignore its ECC. */
-	for (i = 0; i < 10; i++) {
-		if (ecc_code[i] != 0xff)
-			goto compare;
-	}
-	return 0;
-
-compare:
 	/* Unpack ten bytes into eight 10 bit values.  We know we're
 	 * little-endian, and use type punning for less shifting/masking.
 	 */
diff --git a/drivers/mtd/nand/diskonchip.c b/drivers/mtd/nand/diskonchip.c
index 7da266a..eb65769 100644
--- a/drivers/mtd/nand/diskonchip.c
+++ b/drivers/mtd/nand/diskonchip.c
@@ -936,37 +936,9 @@ static int doc200x_correct_data(struct mtd_info *mtd, u_char *dat,
 				calc_ecc[i] = ReadDOC_(docptr, DoC_Mplus_ECCSyndrome0 + i);
 			else
 				calc_ecc[i] = ReadDOC_(docptr, DoC_ECCSyndrome0 + i);
-			if (calc_ecc[i] != empty_read_syndrome[i])
-				emptymatch = 0;
 		}
-		/* If emptymatch=1, the read syndrome is consistent with an
-		   all-0xff data and stored ecc block.  Check the stored ecc. */
-		if (emptymatch) {
-			for (i = 0; i < 6; i++) {
-				if (read_ecc[i] == 0xff)
-					continue;
-				emptymatch = 0;
-				break;
-			}
-		}
-		/* If emptymatch still =1, check the data block. */
-		if (emptymatch) {
-			/* Note: this somewhat expensive test should not be triggered
-			   often.  It could be optimized away by examining the data in
-			   the readbuf routine, and remembering the result. */
-			for (i = 0; i < 512; i++) {
-				if (dat[i] == 0xff)
-					continue;
-				emptymatch = 0;
-				break;
-			}
-		}
-		/* If emptymatch still =1, this is almost certainly a freshly-
-		   erased block, in which case the ECC will not come out right.
-		   We'll suppress the error and tell the caller everything's
-		   OK.  Because it is. */
-		if (!emptymatch)
-			ret = doc_ecc_decode(rs_decoder, dat, calc_ecc);
+
+		ret = doc_ecc_decode(rs_decoder, dat, calc_ecc);
 		if (ret > 0)
 			printk(KERN_ERR "doc200x_correct_data corrected %d errors\n", ret);
 	}
diff --git a/drivers/mtd/nand/jz4740_nand.c b/drivers/mtd/nand/jz4740_nand.c
index ba44af3..4d73276 100644
--- a/drivers/mtd/nand/jz4740_nand.c
+++ b/drivers/mtd/nand/jz4740_nand.c
@@ -224,24 +224,6 @@ static int jz_nand_correct_ecc_rs(struct mtd_info *mtd, uint8_t *dat,
 	uint32_t t;
 	unsigned int timeout = 1000;
 
-	t = read_ecc[0];
-
-	if (t == 0xff) {
-		for (i = 1; i < 9; ++i)
-			t &= read_ecc[i];
-
-		t &= dat[0];
-		t &= dat[nand->chip.ecc.size / 2];
-		t &= dat[nand->chip.ecc.size - 1];
-
-		if (t == 0xff) {
-			for (i = 1; i < nand->chip.ecc.size - 1; ++i)
-				t &= dat[i];
-			if (t == 0xff)
-				return 0;
-		}
-	}
-
 	for (i = 0; i < 9; ++i)
 		writeb(read_ecc[i], nand->base + JZ_REG_NAND_PAR0 + i);
 
-- 
1.9.1