ubi-utils: nand2bin had ECC calculation problems

Fixed a problem when ECC was checked. The correction was not properly
done by subpage. Added more output for the moment to be able to figure
out more potential problems.
    
Added testcase: bin2nand2bin.sh and biterror inject program inject_biterror.pl
    
Interface
  o ECC correction disabled by default. Switch to turn it
    explicitly on. The user must specify what he wants to be done.
   
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/ubi-utils/src/nandcorr.c b/ubi-utils/src/nandcorr.c
index 7f1a547..caa07e2 100644
--- a/ubi-utils/src/nandcorr.c
+++ b/ubi-utils/src/nandcorr.c
@@ -36,8 +36,15 @@ static int countbits(uint32_t byte)
 	return res;
 }
 
-int nand_correct_data(uint8_t *dat, const uint8_t *fail_ecc)
-
+/**
+ * @dat:       data which should be corrected
+ * @read_ecc:  ecc information read from flash
+ * @calc_ecc:  calculated ecc information from the data
+ * @return:    number of corrected bytes
+ *             or -1 when no correction is possible
+ */
+int nand_correct_data(uint8_t *dat, const uint8_t *read_ecc,
+		      const uint8_t *calc_ecc)
 {
 	uint8_t s0, s1, s2;
 
@@ -47,9 +54,12 @@ int nand_correct_data(uint8_t *dat, const uint8_t *fail_ecc)
 	 * Be careful, the index magic is due to a pointer to a
 	 * uint32_t.
 	 */
-	s0 = fail_ecc[1];
-	s1 = fail_ecc[2];
-	s2 = fail_ecc[3];
+	s0 = calc_ecc[0] ^ read_ecc[0];
+	s1 = calc_ecc[1] ^ read_ecc[1];
+	s2 = calc_ecc[2] ^ read_ecc[2];
+
+	if ((s0 | s1 | s2) == 0)
+		return 0;
 
 	/* Check for a single bit error */
 	if( ((s0 ^ (s0 >> 1)) & 0x55) == 0x55 &&