Tweaks to YaffsTuning doc.

[yaffs2.git] / yaffs_ecc.c

diff --git a/yaffs_ecc.c b/yaffs_ecc.c
index be860d01a6f3853695efb2a9184bb43ffe728927..d037e90a2472c39b032096dd344b5f0f86e9ce97 100644 (file)
--- a/yaffs_ecc.c
+++ b/yaffs_ecc.c
@@ -14,9 +14,9 @@
 /*
  * This code implements the ECC algorithm used in SmartMedia.
  *
- * The ECC comprises 22 bits of parity information and is stuffed into 3 bytes. 
+ * The ECC comprises 22 bits of parity information and is stuffed into 3 bytes.
  * The two unused bit are set to 1.
- * The ECC can correct single bit errors in a 256-byte page of data. Thus, two such ECC 
+ * The ECC can correct single bit errors in a 256-byte page of data. Thus, two such ECC
  * blocks are used on a 512-byte NAND page.
  *
  */
@@ -29,7 +29,7 @@
  */
 
 const char *yaffs_ecc_c_version =
-    "$Id: yaffs_ecc.c,v 1.9 2007-02-14 01:09:06 wookey Exp $";
+       "$Id: yaffs_ecc.c,v 1.11 2009-03-06 17:20:50 wookey Exp $";
 
 #include "yportenv.h"
 
@@ -109,12 +109,10 @@ void yaffs_ECCCalculate(const unsigned char *data, unsigned char *ecc)
                b = column_parity_table[*data++];
                col_parity ^= b;
 
-               if (b & 0x01)   // odd number of bits in the byte
-               {
+               if (b & 0x01) {         /* odd number of bits in the byte */
                        line_parity ^= i;
                        line_parity_prime ^= ~i;
                }
-
        }
 
        ecc[2] = (~col_parity) | 0x03;
@@ -158,7 +156,7 @@ void yaffs_ECCCalculate(const unsigned char *data, unsigned char *ecc)
        ecc[0] = ~t;
 
 #ifdef CONFIG_YAFFS_ECC_WRONG_ORDER
-       // Swap the bytes into the wrong order
+       /* Swap the bytes into the wrong order */
        t = ecc[0];
        ecc[0] = ecc[1];
        ecc[1] = t;
@@ -189,7 +187,7 @@ int yaffs_ECCCorrect(unsigned char *data, unsigned char *read_ecc,
                unsigned bit;
 
 #ifdef CONFIG_YAFFS_ECC_WRONG_ORDER
-               // swap the bytes to correct for the wrong order
+               /* swap the bytes to correct for the wrong order */
                unsigned char t;
 
                t = d0;
@@ -228,8 +226,8 @@ int yaffs_ECCCorrect(unsigned char *data, unsigned char *read_ecc,
                return 1; /* Corrected the error */
        }
 
-       if ((yaffs_CountBits(d0) + 
-            yaffs_CountBits(d1) + 
+       if ((yaffs_CountBits(d0) +
+            yaffs_CountBits(d1) +
             yaffs_CountBits(d2)) ==  1) {
                /* Reccoverable error in ecc */
 
@@ -239,7 +237,7 @@ int yaffs_ECCCorrect(unsigned char *data, unsigned char *read_ecc,
 
                return 1; /* Corrected the error */
        }
-       
+
        /* Unrecoverable error */
 
        return -1;
@@ -251,7 +249,7 @@ int yaffs_ECCCorrect(unsigned char *data, unsigned char *read_ecc,
  * ECCxxxOther does ECC calcs on arbitrary n bytes of data
  */
 void yaffs_ECCCalculateOther(const unsigned char *data, unsigned nBytes,
-                            yaffs_ECCOther * eccOther)
+                               yaffs_ECCOther *eccOther)
 {
        unsigned int i;
 
@@ -278,8 +276,8 @@ void yaffs_ECCCalculateOther(const unsigned char *data, unsigned nBytes,
 }
 
 int yaffs_ECCCorrectOther(unsigned char *data, unsigned nBytes,
-                         yaffs_ECCOther * read_ecc,
-                         const yaffs_ECCOther * test_ecc)
+                       yaffs_ECCOther *read_ecc,
+                       const yaffs_ECCOther *test_ecc)
 {
        unsigned char cDelta;   /* column parity delta */
        unsigned lDelta;        /* line parity delta */
@@ -293,9 +291,8 @@ int yaffs_ECCCorrectOther(unsigned char *data, unsigned nBytes,
        if ((cDelta | lDelta | lDeltaPrime) == 0)
                return 0; /* no error */
 
-       if (lDelta == ~lDeltaPrime && 
-           (((cDelta ^ (cDelta >> 1)) & 0x15) == 0x15))
-       {
+       if (lDelta == ~lDeltaPrime &&
+           (((cDelta ^ (cDelta >> 1)) & 0x15) == 0x15)) {
                /* Single bit (recoverable) error in data */
 
                bit = 0;
@@ -307,16 +304,16 @@ int yaffs_ECCCorrectOther(unsigned char *data, unsigned nBytes,
                if (cDelta & 0x02)
                        bit |= 0x01;
 
-               if(lDelta >= nBytes)
+               if (lDelta >= nBytes)
                        return -1;
-                       
+
                data[lDelta] ^= (1 << bit);
 
                return 1; /* corrected */
        }
 
        if ((yaffs_CountBits32(lDelta) + yaffs_CountBits32(lDeltaPrime) +
-            yaffs_CountBits(cDelta)) == 1) {
+                       yaffs_CountBits(cDelta)) == 1) {
                /* Reccoverable error in ecc */
 
                *read_ecc = *test_ecc;
@@ -326,6 +323,4 @@ int yaffs_ECCCorrectOther(unsigned char *data, unsigned nBytes,
        /* Unrecoverable error */
 
        return -1;
-
 }
-