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_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_SMC)); 126 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size, 127 IS_ENABLED(CONFIG_MTD_NAND_ECC_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_SMC)); 156 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size, 157 IS_ENABLED(CONFIG_MTD_NAND_ECC_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_SMC)); 193 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size, 194 IS_ENABLED(CONFIG_MTD_NAND_ECC_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_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"); 330