drivers/mtd/tests/mtd_nandecctest.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
   3
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/list.h>
   7 #include <linux/random.h>
   8 #include <linux/string.h>
   9 #include <linux/bitops.h>
  10 #include <linux/slab.h>
  11 #include <linux/mtd/nand-ecc-sw-hamming.h>
  12
  13 #include "mtd_test.h"
  14
  15 /*
  16  * Test the implementation for software ECC
  17  *
  18  * No actual MTD device is needed, So we don't need to warry about losing
  19  * important data by human error.
  20  *
  21  * This covers possible patterns of corruption which can be reliably corrected
  22  * or detected.
  23  */
  24
  25 #if IS_ENABLED(CONFIG_MTD_RAW_NAND)
  26
  27 struct nand_ecc_test {
  28         const char *name;
  29         void (*prepare)(void *, void *, void *, void *, const size_t);
  30         int (*verify)(void *, void *, void *, const size_t);
  31 };
  32
  33 /*
  34  * The reason for this __change_bit_le() instead of __change_bit() is to inject
  35  * bit error properly within the region which is not a multiple of
  36  * sizeof(unsigned long) on big-endian systems
  37  */
  38 #ifdef __LITTLE_ENDIAN
  39 #define __change_bit_le(nr, addr) __change_bit(nr, addr)
  40 #elif defined(__BIG_ENDIAN)
  41 #define __change_bit_le(nr, addr) \
  42                 __change_bit((nr) ^ ((BITS_PER_LONG - 1) & ~0x7), addr)
  43 #else
  44 #error "Unknown byte order"
  45 #endif
  46
  47 static void single_bit_error_data(void *error_data, void *correct_data,
  48                                 size_t size)
  49 {
  50         unsigned int offset = prandom_u32() % (size * BITS_PER_BYTE);
  51
  52         memcpy(error_data, correct_data, size);
  53         __change_bit_le(offset, error_data);
  54 }
  55
  56 static void double_bit_error_data(void *error_data, void *correct_data,
  57                                 size_t size)
  58 {
  59         unsigned int offset[2];
  60
  61         offset[0] = prandom_u32() % (size * BITS_PER_BYTE);
  62         do {
  63                 offset[1] = prandom_u32() % (size * BITS_PER_BYTE);
  64         } while (offset[0] == offset[1]);
  65
  66         memcpy(error_data, correct_data, size);
  67
  68         __change_bit_le(offset[0], error_data);
  69         __change_bit_le(offset[1], error_data);
  70 }
  71
  72 static unsigned int random_ecc_bit(size_t size)
  73 {
  74         unsigned int offset = prandom_u32() % (3 * BITS_PER_BYTE);
  75
  76         if (size == 256) {
  77                 /*
  78                  * Don't inject a bit error into the insignificant bits (16th
  79                  * and 17th bit) in ECC code for 256 byte data block
  80                  */
  81                 while (offset == 16 || offset == 17)
  82                         offset = prandom_u32() % (3 * BITS_PER_BYTE);
  83         }
  84
  85         return offset;
  86 }
  87
  88 static void single_bit_error_ecc(void *error_ecc, void *correct_ecc,
  89                                 size_t size)
  90 {
  91         unsigned int offset = random_ecc_bit(size);
  92
  93         memcpy(error_ecc, correct_ecc, 3);
  94         __change_bit_le(offset, error_ecc);
  95 }
  96
  97 static void double_bit_error_ecc(void *error_ecc, void *correct_ecc,
  98                                 size_t size)
  99 {
 100         unsigned int offset[2];
 101
 102         offset[0] = random_ecc_bit(size);
 103         do {
 104                 offset[1] = random_ecc_bit(size);
 105         } while (offset[0] == offset[1]);
 106
 107         memcpy(error_ecc, correct_ecc, 3);
 108         __change_bit_le(offset[0], error_ecc);
 109         __change_bit_le(offset[1], error_ecc);
 110 }
 111
 112 static void no_bit_error(void *error_data, void *error_ecc,
 113                 void *correct_data, void *correct_ecc, const size_t size)
 114 {
 115         memcpy(error_data, correct_data, size);
 116         memcpy(error_ecc, correct_ecc, 3);
 117 }
 118
 119 static int no_bit_error_verify(void *error_data, void *error_ecc,
 120                                 void *correct_data, const size_t size)
 121 {
 122         bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
 123         unsigned char calc_ecc[3];
 124         int ret;
 125
 126         ecc_sw_hamming_calculate(error_data, size, calc_ecc, sm_order);
 127         ret = ecc_sw_hamming_correct(error_data, error_ecc, calc_ecc, size,
 128                                      sm_order);
 129         if (ret == 0 && !memcmp(correct_data, error_data, size))
 130                 return 0;
 131
 132         return -EINVAL;
 133 }
 134
 135 static void single_bit_error_in_data(void *error_data, void *error_ecc,
 136                 void *correct_data, void *correct_ecc, const size_t size)
 137 {
 138         single_bit_error_data(error_data, correct_data, size);
 139         memcpy(error_ecc, correct_ecc, 3);
 140 }
 141
 142 static void single_bit_error_in_ecc(void *error_data, void *error_ecc,
 143                 void *correct_data, void *correct_ecc, const size_t size)
 144 {
 145         memcpy(error_data, correct_data, size);
 146         single_bit_error_ecc(error_ecc, correct_ecc, size);
 147 }
 148
 149 static int single_bit_error_correct(void *error_data, void *error_ecc,
 150                                 void *correct_data, const size_t size)
 151 {
 152         bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
 153         unsigned char calc_ecc[3];
 154         int ret;
 155
 156         ecc_sw_hamming_calculate(error_data, size, calc_ecc, sm_order);
 157         ret = ecc_sw_hamming_correct(error_data, error_ecc, calc_ecc, size,
 158                                      sm_order);
 159         if (ret == 1 && !memcmp(correct_data, error_data, size))
 160                 return 0;
 161
 162         return -EINVAL;
 163 }
 164
 165 static void double_bit_error_in_data(void *error_data, void *error_ecc,
 166                 void *correct_data, void *correct_ecc, const size_t size)
 167 {
 168         double_bit_error_data(error_data, correct_data, size);
 169         memcpy(error_ecc, correct_ecc, 3);
 170 }
 171
 172 static void single_bit_error_in_data_and_ecc(void *error_data, void *error_ecc,
 173                 void *correct_data, void *correct_ecc, const size_t size)
 174 {
 175         single_bit_error_data(error_data, correct_data, size);
 176         single_bit_error_ecc(error_ecc, correct_ecc, size);
 177 }
 178
 179 static void double_bit_error_in_ecc(void *error_data, void *error_ecc,
 180                 void *correct_data, void *correct_ecc, const size_t size)
 181 {
 182         memcpy(error_data, correct_data, size);
 183         double_bit_error_ecc(error_ecc, correct_ecc, size);
 184 }
 185
 186 static int double_bit_error_detect(void *error_data, void *error_ecc,
 187                                 void *correct_data, const size_t size)
 188 {
 189         bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
 190         unsigned char calc_ecc[3];
 191         int ret;
 192
 193         ecc_sw_hamming_calculate(error_data, size, calc_ecc, sm_order);
 194         ret = ecc_sw_hamming_correct(error_data, error_ecc, calc_ecc, size,
 195                                      sm_order);
 196
 197         return (ret == -EBADMSG) ? 0 : -EINVAL;
 198 }
 199
 200 static const struct nand_ecc_test nand_ecc_test[] = {
 201         {
 202                 .name = "no-bit-error",
 203                 .prepare = no_bit_error,
 204                 .verify = no_bit_error_verify,
 205         },
 206         {
 207                 .name = "single-bit-error-in-data-correct",
 208                 .prepare = single_bit_error_in_data,
 209                 .verify = single_bit_error_correct,
 210         },
 211         {
 212                 .name = "single-bit-error-in-ecc-correct",
 213                 .prepare = single_bit_error_in_ecc,
 214                 .verify = single_bit_error_correct,
 215         },
 216         {
 217                 .name = "double-bit-error-in-data-detect",
 218                 .prepare = double_bit_error_in_data,
 219                 .verify = double_bit_error_detect,
 220         },
 221         {
 222                 .name = "single-bit-error-in-data-and-ecc-detect",
 223                 .prepare = single_bit_error_in_data_and_ecc,
 224                 .verify = double_bit_error_detect,
 225         },
 226         {
 227                 .name = "double-bit-error-in-ecc-detect",
 228                 .prepare = double_bit_error_in_ecc,
 229                 .verify = double_bit_error_detect,
 230         },
 231 };
 232
 233 static void dump_data_ecc(void *error_data, void *error_ecc, void *correct_data,
 234                         void *correct_ecc, const size_t size)
 235 {
 236         pr_info("hexdump of error data:\n");
 237         print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4,
 238                         error_data, size, false);
 239         print_hex_dump(KERN_INFO, "hexdump of error ecc: ",
 240                         DUMP_PREFIX_NONE, 16, 1, error_ecc, 3, false);
 241
 242         pr_info("hexdump of correct data:\n");
 243         print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4,
 244                         correct_data, size, false);
 245         print_hex_dump(KERN_INFO, "hexdump of correct ecc: ",
 246                         DUMP_PREFIX_NONE, 16, 1, correct_ecc, 3, false);
 247 }
 248
 249 static int nand_ecc_test_run(const size_t size)
 250 {
 251         bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
 252         int i;
 253         int err = 0;
 254         void *error_data;
 255         void *error_ecc;
 256         void *correct_data;
 257         void *correct_ecc;
 258
 259         error_data = kmalloc(size, GFP_KERNEL);
 260         error_ecc = kmalloc(3, GFP_KERNEL);
 261         correct_data = kmalloc(size, GFP_KERNEL);
 262         correct_ecc = kmalloc(3, GFP_KERNEL);
 263
 264         if (!error_data || !error_ecc || !correct_data || !correct_ecc) {
 265                 err = -ENOMEM;
 266                 goto error;
 267         }
 268
 269         prandom_bytes(correct_data, size);
 270         ecc_sw_hamming_calculate(correct_data, size, correct_ecc, sm_order);
 271         for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) {
 272                 nand_ecc_test[i].prepare(error_data, error_ecc,
 273                                 correct_data, correct_ecc, size);
 274                 err = nand_ecc_test[i].verify(error_data, error_ecc,
 275                                                 correct_data, size);
 276
 277                 if (err) {
 278                         pr_err("not ok - %s-%zd\n",
 279                                 nand_ecc_test[i].name, size);
 280                         dump_data_ecc(error_data, error_ecc,
 281                                 correct_data, correct_ecc, size);
 282                         break;
 283                 }
 284                 pr_info("ok - %s-%zd\n",
 285                         nand_ecc_test[i].name, size);
 286
 287                 err = mtdtest_relax();
 288                 if (err)
 289                         break;
 290         }
 291 error:
 292         kfree(error_data);
 293         kfree(error_ecc);
 294         kfree(correct_data);
 295         kfree(correct_ecc);
 296
 297         return err;
 298 }
 299
 300 #else
 301
 302 static int nand_ecc_test_run(const size_t size)
 303 {
 304         return 0;
 305 }
 306
 307 #endif
 308
 309 static int __init ecc_test_init(void)
 310 {
 311         int err;
 312
 313         err = nand_ecc_test_run(256);
 314         if (err)
 315                 return err;
 316
 317         return nand_ecc_test_run(512);
 318 }
 319
 320 static void __exit ecc_test_exit(void)
 321 {
 322 }
 323
 324 module_init(ecc_test_init);
 325 module_exit(ecc_test_exit);
 326
 327 MODULE_DESCRIPTION("NAND ECC function test module");
 328 MODULE_AUTHOR("Akinobu Mita");
 329 MODULE_LICENSE("GPL");