drivers/mtd/tests/mtd_nandecctest.c

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