linux-imx

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/list.h>

#include <linux/random.h>

#include <linux/string.h>

#include <linux/bitops.h>

#include <linux/slab.h>

#include <linux/mtd/nand_ecc.h>

​

#include "mtd_test.h"

​

/*

 * Test the implementation for software ECC

 *

 * No actual MTD device is needed, So we don't need to warry about losing

 * important data by human error.

 *

 * This covers possible patterns of corruption which can be reliably corrected

 * or detected.

 */

​

#if IS_ENABLED(CONFIG_MTD_NAND)

​

struct nand_ecc_test {

    const char *name;

    void (*prepare)(void *, void *, void *, void *, const size_t);

    int (*verify)(void *, void *, void *, const size_t);

};

​

/*

 * The reason for this __change_bit_le() instead of __change_bit() is to inject

 * bit error properly within the region which is not a multiple of

 * sizeof(unsigned long) on big-endian systems

 */

#ifdef __LITTLE_ENDIAN

#define __change_bit_le(nr, addr) __change_bit(nr, addr)

#elif defined(__BIG_ENDIAN)

#define __change_bit_le(nr, addr) \

        __change_bit((nr) ^ ((BITS_PER_LONG - 1) & ~0x7), addr)

#else

#error "Unknown byte order"

#endif

​

static void single_bit_error_data(void *error_data, void *correct_data,

                size_t size)

{

    unsigned int offset = prandom_u32() % (size * BITS_PER_BYTE);

​

    memcpy(error_data, correct_data, size);

    __change_bit_le(offset, error_data);

}

​

static void double_bit_error_data(void *error_data, void *correct_data,

                size_t size)

{

    unsigned int offset[2];

​

    offset[0] = prandom_u32() % (size * BITS_PER_BYTE);

    do {

        offset[1] = prandom_u32() % (size * BITS_PER_BYTE);

    } while (offset[0] == offset[1]);

​

    memcpy(error_data, correct_data, size);

​

    __change_bit_le(offset[0], error_data);

    __change_bit_le(offset[1], error_data);

}

​

static unsigned int random_ecc_bit(size_t size)

{

    unsigned int offset = prandom_u32() % (3 * BITS_PER_BYTE);

​

    if (size == 256) {

        /*

         * Don't inject a bit error into the insignificant bits (16th

         * and 17th bit) in ECC code for 256 byte data block

         */

        while (offset == 16 || offset == 17)

            offset = prandom_u32() % (3 * BITS_PER_BYTE);

    }

​

    return offset;

}

​

static void single_bit_error_ecc(void *error_ecc, void *correct_ecc,

                size_t size)

{

    unsigned int offset = random_ecc_bit(size);

​

    memcpy(error_ecc, correct_ecc, 3);