--- /dev/null
+#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);
+ __change_bit_le(offset, error_ecc);
+}
+
+static void double_bit_error_ecc(void *error_ecc, void *correct_ecc,
+ size_t size)
+{
+ unsigned int offset[2];
+
+ offset[0] = random_ecc_bit(size);
+ do {
+ offset[1] = random_ecc_bit(size);
+ } while (offset[0] == offset[1]);
+
+ memcpy(error_ecc, correct_ecc, 3);
+ __change_bit_le(offset[0], error_ecc);
+ __change_bit_le(offset[1], error_ecc);
+}
+
+static void no_bit_error(void *error_data, void *error_ecc,
+ void *correct_data, void *correct_ecc, const size_t size)
+{
+ memcpy(error_data, correct_data, size);
+ memcpy(error_ecc, correct_ecc, 3);
+}
+
+static int no_bit_error_verify(void *error_data, void *error_ecc,
+ void *correct_data, const size_t size)
+{
+ unsigned char calc_ecc[3];
+ int ret;
+
+ __nand_calculate_ecc(error_data, size, calc_ecc);
+ ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size);
+ if (ret == 0 && !memcmp(correct_data, error_data, size))
+ return 0;
+
+ return -EINVAL;
+}
+
+static void single_bit_error_in_data(void *error_data, void *error_ecc,
+ void *correct_data, void *correct_ecc, const size_t size)
+{
+ single_bit_error_data(error_data, correct_data, size);
+ memcpy(error_ecc, correct_ecc, 3);
+}
+
+static void single_bit_error_in_ecc(void *error_data, void *error_ecc,
+ void *correct_data, void *correct_ecc, const size_t size)
+{
+ memcpy(error_data, correct_data, size);
+ single_bit_error_ecc(error_ecc, correct_ecc, size);
+}
+
+static int single_bit_error_correct(void *error_data, void *error_ecc,
+ void *correct_data, const size_t size)
+{
+ unsigned char calc_ecc[3];
+ int ret;
+
+ __nand_calculate_ecc(error_data, size, calc_ecc);
+ ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size);
+ if (ret == 1 && !memcmp(correct_data, error_data, size))
+ return 0;
+
+ return -EINVAL;
+}
+
+static void double_bit_error_in_data(void *error_data, void *error_ecc,
+ void *correct_data, void *correct_ecc, const size_t size)
+{
+ double_bit_error_data(error_data, correct_data, size);
+ memcpy(error_ecc, correct_ecc, 3);
+}
+
+static void single_bit_error_in_data_and_ecc(void *error_data, void *error_ecc,
+ void *correct_data, void *correct_ecc, const size_t size)
+{
+ single_bit_error_data(error_data, correct_data, size);
+ single_bit_error_ecc(error_ecc, correct_ecc, size);
+}
+
+static void double_bit_error_in_ecc(void *error_data, void *error_ecc,
+ void *correct_data, void *correct_ecc, const size_t size)
+{
+ memcpy(error_data, correct_data, size);
+ double_bit_error_ecc(error_ecc, correct_ecc, size);
+}
+
+static int double_bit_error_detect(void *error_data, void *error_ecc,
+ void *correct_data, const size_t size)
+{
+ unsigned char calc_ecc[3];
+ int ret;
+
+ __nand_calculate_ecc(error_data, size, calc_ecc);
+ ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size);
+
+ return (ret == -1) ? 0 : -EINVAL;
+}
+
+static const struct nand_ecc_test nand_ecc_test[] = {
+ {
+ .name = "no-bit-error",
+ .prepare = no_bit_error,
+ .verify = no_bit_error_verify,
+ },
+ {
+ .name = "single-bit-error-in-data-correct",
+ .prepare = single_bit_error_in_data,
+ .verify = single_bit_error_correct,
+ },
+ {
+ .name = "single-bit-error-in-ecc-correct",
+ .prepare = single_bit_error_in_ecc,
+ .verify = single_bit_error_correct,
+ },
+ {
+ .name = "double-bit-error-in-data-detect",
+ .prepare = double_bit_error_in_data,
+ .verify = double_bit_error_detect,
+ },
+ {
+ .name = "single-bit-error-in-data-and-ecc-detect",
+ .prepare = single_bit_error_in_data_and_ecc,
+ .verify = double_bit_error_detect,
+ },
+ {
+ .name = "double-bit-error-in-ecc-detect",
+ .prepare = double_bit_error_in_ecc,
+ .verify = double_bit_error_detect,
+ },
+};
+
+static void dump_data_ecc(void *error_data, void *error_ecc, void *correct_data,
+ void *correct_ecc, const size_t size)
+{
+ pr_info("hexdump of error data:\n");
+ print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4,
+ error_data, size, false);
+ print_hex_dump(KERN_INFO, "hexdump of error ecc: ",
+ DUMP_PREFIX_NONE, 16, 1, error_ecc, 3, false);
+
+ pr_info("hexdump of correct data:\n");
+ print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4,
+ correct_data, size, false);
+ print_hex_dump(KERN_INFO, "hexdump of correct ecc: ",
+ DUMP_PREFIX_NONE, 16, 1, correct_ecc, 3, false);
+}
+
+static int nand_ecc_test_run(const size_t size)
+{
+ int i;
+ int err = 0;
+ void *error_data;
+ void *error_ecc;
+ void *correct_data;
+ void *correct_ecc;
+
+ error_data = kmalloc(size, GFP_KERNEL);
+ error_ecc = kmalloc(3, GFP_KERNEL);
+ correct_data = kmalloc(size, GFP_KERNEL);
+ correct_ecc = kmalloc(3, GFP_KERNEL);
+
+ if (!error_data || !error_ecc || !correct_data || !correct_ecc) {
+ err = -ENOMEM;
+ goto error;
+ }
+
+ prandom_bytes(correct_data, size);
+ __nand_calculate_ecc(correct_data, size, correct_ecc);
+
+ for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) {
+ nand_ecc_test[i].prepare(error_data, error_ecc,
+ correct_data, correct_ecc, size);
+ err = nand_ecc_test[i].verify(error_data, error_ecc,
+ correct_data, size);
+
+ if (err) {
+ pr_err("not ok - %s-%zd\n",
+ nand_ecc_test[i].name, size);
+ dump_data_ecc(error_data, error_ecc,
+ correct_data, correct_ecc, size);
+ break;
+ }
+ pr_info("ok - %s-%zd\n",
+ nand_ecc_test[i].name, size);
+
+ err = mtdtest_relax();
+ if (err)
+ break;
+ }
+error:
+ kfree(error_data);
+ kfree(error_ecc);
+ kfree(correct_data);
+ kfree(correct_ecc);
+
+ return err;
+}
+
+#else
+
+static int nand_ecc_test_run(const size_t size)
+{
+ return 0;
+}
+
+#endif
+
+static int __init ecc_test_init(void)
+{
+ int err;
+
+ err = nand_ecc_test_run(256);
+ if (err)
+ return err;
+
+ return nand_ecc_test_run(512);
+}
+
+static void __exit ecc_test_exit(void)
+{
+}
+
+module_init(ecc_test_init);
+module_exit(ecc_test_exit);
+
+MODULE_DESCRIPTION("NAND ECC function test module");
+MODULE_AUTHOR("Akinobu Mita");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff