--- /dev/null
+/*
+ * This file contains an ECC algorithm from Toshiba that detects and
+ * corrects 1 bit errors in a 256 byte block of data.
+ *
+ * drivers/mtd/nand/nand_ecc.c
+ *
+ * Copyright (C) 2000-2004 Steven J. Hill (sjhill@realitydiluted.com)
+ * Toshiba America Electronics Components, Inc.
+ *
+ * Copyright (C) 2006 Thomas Gleixner <tglx@linutronix.de>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * 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.
+ */
+
+#include <common.h>
+
+#include <asm/errno.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand_ecc.h>
+
+/* The PPC4xx NDFC uses Smart Media (SMC) bytes order */
+#ifdef CONFIG_NAND_NDFC
+#define CONFIG_MTD_NAND_ECC_SMC
+#endif
+
+/*
+ * NAND-SPL has no sofware ECC for now, so don't include nand_calculate_ecc(),
+ * only nand_correct_data() is needed
+ */
+
+#if !defined(CONFIG_NAND_SPL) || defined(CONFIG_SPL_NAND_SOFTECC)
+/*
+ * Pre-calculated 256-way 1 byte column parity
+ */
+static const u_char nand_ecc_precalc_table[] = {
+ 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00,
+ 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
+ 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
+ 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
+ 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
+ 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
+ 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
+ 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
+ 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
+ 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
+ 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
+ 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
+ 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
+ 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
+ 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
+ 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00
+};
+
+/**
+ * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256-byte block
+ * @mtd: MTD block structure
+ * @dat: raw data
+ * @ecc_code: buffer for ECC
+ */
+int nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
+ u_char *ecc_code)
+{
+ uint8_t idx, reg1, reg2, reg3, tmp1, tmp2;
+ int i;
+
+ /* Initialize variables */
+ reg1 = reg2 = reg3 = 0;
+
+ /* Build up column parity */
+ for(i = 0; i < 256; i++) {
+ /* Get CP0 - CP5 from table */
+ idx = nand_ecc_precalc_table[*dat++];
+ reg1 ^= (idx & 0x3f);
+
+ /* All bit XOR = 1 ? */
+ if (idx & 0x40) {
+ reg3 ^= (uint8_t) i;
+ reg2 ^= ~((uint8_t) i);
+ }
+ }
+
+ /* Create non-inverted ECC code from line parity */
+ tmp1 = (reg3 & 0x80) >> 0; /* B7 -> B7 */
+ tmp1 |= (reg2 & 0x80) >> 1; /* B7 -> B6 */
+ tmp1 |= (reg3 & 0x40) >> 1; /* B6 -> B5 */
+ tmp1 |= (reg2 & 0x40) >> 2; /* B6 -> B4 */
+ tmp1 |= (reg3 & 0x20) >> 2; /* B5 -> B3 */
+ tmp1 |= (reg2 & 0x20) >> 3; /* B5 -> B2 */
+ tmp1 |= (reg3 & 0x10) >> 3; /* B4 -> B1 */
+ tmp1 |= (reg2 & 0x10) >> 4; /* B4 -> B0 */
+
+ tmp2 = (reg3 & 0x08) << 4; /* B3 -> B7 */
+ tmp2 |= (reg2 & 0x08) << 3; /* B3 -> B6 */
+ tmp2 |= (reg3 & 0x04) << 3; /* B2 -> B5 */
+ tmp2 |= (reg2 & 0x04) << 2; /* B2 -> B4 */
+ tmp2 |= (reg3 & 0x02) << 2; /* B1 -> B3 */
+ tmp2 |= (reg2 & 0x02) << 1; /* B1 -> B2 */
+ tmp2 |= (reg3 & 0x01) << 1; /* B0 -> B1 */
+ tmp2 |= (reg2 & 0x01) << 0; /* B7 -> B0 */
+
+ /* Calculate final ECC code */
+#ifdef CONFIG_MTD_NAND_ECC_SMC
+ ecc_code[0] = ~tmp2;
+ ecc_code[1] = ~tmp1;
+#else
+ ecc_code[0] = ~tmp1;
+ ecc_code[1] = ~tmp2;
+#endif
+ ecc_code[2] = ((~reg1) << 2) | 0x03;
+
+ return 0;
+}
+#endif /* CONFIG_NAND_SPL */
+
+static inline int countbits(uint32_t byte)
+{
+ int res = 0;
+
+ for (;byte; byte >>= 1)
+ res += byte & 0x01;
+ return res;
+}
+
+/**
+ * nand_correct_data - [NAND Interface] Detect and correct bit error(s)
+ * @mtd: MTD block structure
+ * @dat: raw data read from the chip
+ * @read_ecc: ECC from the chip
+ * @calc_ecc: the ECC calculated from raw data
+ *
+ * Detect and correct a 1 bit error for 256 byte block
+ */
+int nand_correct_data(struct mtd_info *mtd, u_char *dat,
+ u_char *read_ecc, u_char *calc_ecc)
+{
+ uint8_t s0, s1, s2;
+
+#ifdef CONFIG_MTD_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 -EBADMSG;
+}
Code Review / kvmfornfv.git / blobdiff