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.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 unsigned char calc_ecc[3]; 123 int ret; 124 125 __nand_calculate_ecc(error_data, size, calc_ecc, 126 IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC)); 127 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size, 128 IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC)); 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 unsigned char calc_ecc[3]; 153 int ret; 154 155 __nand_calculate_ecc(error_data, size, calc_ecc, 156 IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC)); 157 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size, 158 IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC)); 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 unsigned char calc_ecc[3]; 190 int ret; 191 192 __nand_calculate_ecc(error_data, size, calc_ecc, 193 IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC)); 194 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size, 195 IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC)); 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 int i; 252 int err = 0; 253 void *error_data; 254 void *error_ecc; 255 void *correct_data; 256 void *correct_ecc; 257 258 error_data = kmalloc(size, GFP_KERNEL); 259 error_ecc = kmalloc(3, GFP_KERNEL); 260 correct_data = kmalloc(size, GFP_KERNEL); 261 correct_ecc = kmalloc(3, GFP_KERNEL); 262 263 if (!error_data || !error_ecc || !correct_data || !correct_ecc) { 264 err = -ENOMEM; 265 goto error; 266 } 267 268 prandom_bytes(correct_data, size); 269 __nand_calculate_ecc(correct_data, size, correct_ecc, 270 IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC)); 271 272 for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) { 273 nand_ecc_test[i].prepare(error_data, error_ecc, 274 correct_data, correct_ecc, size); 275 err = nand_ecc_test[i].verify(error_data, error_ecc, 276 correct_data, size); 277 278 if (err) { 279 pr_err("not ok - %s-%zd\n", 280 nand_ecc_test[i].name, size); 281 dump_data_ecc(error_data, error_ecc, 282 correct_data, correct_ecc, size); 283 break; 284 } 285 pr_info("ok - %s-%zd\n", 286 nand_ecc_test[i].name, size); 287 288 err = mtdtest_relax(); 289 if (err) 290 break; 291 } 292 error: 293 kfree(error_data); 294 kfree(error_ecc); 295 kfree(correct_data); 296 kfree(correct_ecc); 297 298 return err; 299 } 300 301 #else 302 303 static int nand_ecc_test_run(const size_t size) 304 { 305 return 0; 306 } 307 308 #endif 309 310 static int __init ecc_test_init(void) 311 { 312 int err; 313 314 err = nand_ecc_test_run(256); 315 if (err) 316 return err; 317 318 return nand_ecc_test_run(512); 319 } 320 321 static void __exit ecc_test_exit(void) 322 { 323 } 324 325 module_init(ecc_test_init); 326 module_exit(ecc_test_exit); 327 328 MODULE_DESCRIPTION("NAND ECC function test module"); 329 MODULE_AUTHOR("Akinobu Mita"); 330 MODULE_LICENSE("GPL"); 331