X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=blobdiff_plain;f=src%2Fflash%2Fnand%2Fecc.c;h=25b2eb10e319b3fbcafa0de592e7beabc0f2cd3b;hp=1e103d00210a231e2f5cca96c42633f20f90eced;hb=HEAD;hpb=da3bcb392e852214b0dda878f6161c8f1e8d15f3

diff --git a/src/flash/nand/ecc.c b/src/flash/nand/ecc.c
index 1e103d0021..20b8ba85dc 100644
--- a/src/flash/nand/ecc.c
+++ b/src/flash/nand/ecc.c
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-or-later WITH eCos-exception-2.0
+
 /*
  * This file contains an ECC algorithm from Toshiba that allows for detection
  * and correction of 1-bit errors in a 256 byte block of data.
@@ -10,38 +12,13 @@
  *                         Toshiba America Electronics Components, Inc.
  *
  * Copyright (C) 2006 Thomas Gleixner <tglx at linutronix.de>
- *
- * This file is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 or (at your option) any
- * later version.
- *
- * This file is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this file; if not, write to the Free Software Foundation, Inc.,
- * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
- *
- * As a special exception, if other files instantiate templates or use
- * macros or inline functions from these files, or you compile these
- * files and link them with other works to produce a work based on these
- * files, these files do not by themselves cause the resulting work to be
- * covered by the GNU General Public License. However the source code for
- * these files must still be made available in accordance with section (3)
- * of the GNU General Public License.
- *
- * This exception does not invalidate any other reasons why a work based on
- * this file might be covered by the GNU General Public License.
  */
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#include <flash/nand.h>
+#include "core.h"
 
 /*
  * Pre-calculated 256-way 1 byte column parity
@@ -120,3 +97,64 @@ int nand_calculate_ecc(struct nand_device *nand, const uint8_t *dat, uint8_t *ec
 
 	return 0;
 }
+
+static inline int countbits(uint32_t b)
+{
+	int res = 0;
+
+	for (; b; b >>= 1)
+		res += b & 0x01;
+	return res;
+}
+
+/**
+ * nand_correct_data - Detect and correct a 1 bit error for 256 byte block
+ */
+int nand_correct_data(struct nand_device *nand, u_char *dat,
+		u_char *read_ecc, u_char *calc_ecc)
+{
+	uint8_t s0, s1, s2;
+
+#ifdef NAND_ECC_SMC
+	s0 = calc_ecc[0] ^ read_ecc[0];
+	s1 = calc_ecc[1] ^ read_ecc[1];
+	s2 = calc_ecc[2] ^ read_ecc[2];
+#else
+	s1 = calc_ecc[0] ^ read_ecc[0];
+	s0 = calc_ecc[1] ^ read_ecc[1];
+	s2 = calc_ecc[2] ^ read_ecc[2];
+#endif
+	if ((s0 | s1 | s2) == 0)
+		return 0;
+
+	/* Check for a single bit error */
+	if (((s0 ^ (s0 >> 1)) & 0x55) == 0x55 &&
+			((s1 ^ (s1 >> 1)) & 0x55) == 0x55 &&
+			((s2 ^ (s2 >> 1)) & 0x54) == 0x54) {
+
+		uint32_t byteoffs, bitnum;
+
+		byteoffs = (s1 << 0) & 0x80;
+		byteoffs |= (s1 << 1) & 0x40;
+		byteoffs |= (s1 << 2) & 0x20;
+		byteoffs |= (s1 << 3) & 0x10;
+
+		byteoffs |= (s0 >> 4) & 0x08;
+		byteoffs |= (s0 >> 3) & 0x04;
+		byteoffs |= (s0 >> 2) & 0x02;
+		byteoffs |= (s0 >> 1) & 0x01;
+
+		bitnum = (s2 >> 5) & 0x04;
+		bitnum |= (s2 >> 4) & 0x02;
+		bitnum |= (s2 >> 3) & 0x01;
+
+		dat[byteoffs] ^= (1 << bitnum);
+
+		return 1;
+	}
+
+	if (countbits(s0 | ((uint32_t)s1 << 8) | ((uint32_t)s2 << 16)) == 1)
+		return 1;
+
+	return -1;
+}