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 26struct 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 46static 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 55static 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 71static 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 87static 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 96static 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 111static 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 118static 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 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size); 126 if (ret == 0 && !memcmp(correct_data, error_data, size)) 127 return 0; 128 129 return -EINVAL; 130} 131 132static void single_bit_error_in_data(void *error_data, void *error_ecc, 133 void *correct_data, void *correct_ecc, const size_t size) 134{ 135 single_bit_error_data(error_data, correct_data, size); 136 memcpy(error_ecc, correct_ecc, 3); 137} 138 139static void single_bit_error_in_ecc(void *error_data, void *error_ecc, 140 void *correct_data, void *correct_ecc, const size_t size) 141{ 142 memcpy(error_data, correct_data, size); 143 single_bit_error_ecc(error_ecc, correct_ecc, size); 144} 145 146static int single_bit_error_correct(void *error_data, void *error_ecc, 147 void *correct_data, const size_t size) 148{ 149 unsigned char calc_ecc[3]; 150 int ret; 151 152 __nand_calculate_ecc(error_data, size, calc_ecc); 153 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size); 154 if (ret == 1 && !memcmp(correct_data, error_data, size)) 155 return 0; 156 157 return -EINVAL; 158} 159 160static void double_bit_error_in_data(void *error_data, void *error_ecc, 161 void *correct_data, void *correct_ecc, const size_t size) 162{ 163 double_bit_error_data(error_data, correct_data, size); 164 memcpy(error_ecc, correct_ecc, 3); 165} 166 167static void single_bit_error_in_data_and_ecc(void *error_data, void *error_ecc, 168 void *correct_data, void *correct_ecc, const size_t size) 169{ 170 single_bit_error_data(error_data, correct_data, size); 171 single_bit_error_ecc(error_ecc, correct_ecc, size); 172} 173 174static void double_bit_error_in_ecc(void *error_data, void *error_ecc, 175 void *correct_data, void *correct_ecc, const size_t size) 176{ 177 memcpy(error_data, correct_data, size); 178 double_bit_error_ecc(error_ecc, correct_ecc, size); 179} 180 181static int double_bit_error_detect(void *error_data, void *error_ecc, 182 void *correct_data, const size_t size) 183{ 184 unsigned char calc_ecc[3]; 185 int ret; 186 187 __nand_calculate_ecc(error_data, size, calc_ecc); 188 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size); 189 190 return (ret == -1) ? 0 : -EINVAL; 191} 192 193static const struct nand_ecc_test nand_ecc_test[] = { 194 { 195 .name = "no-bit-error", 196 .prepare = no_bit_error, 197 .verify = no_bit_error_verify, 198 }, 199 { 200 .name = "single-bit-error-in-data-correct", 201 .prepare = single_bit_error_in_data, 202 .verify = single_bit_error_correct, 203 }, 204 { 205 .name = "single-bit-error-in-ecc-correct", 206 .prepare = single_bit_error_in_ecc, 207 .verify = single_bit_error_correct, 208 }, 209 { 210 .name = "double-bit-error-in-data-detect", 211 .prepare = double_bit_error_in_data, 212 .verify = double_bit_error_detect, 213 }, 214 { 215 .name = "single-bit-error-in-data-and-ecc-detect", 216 .prepare = single_bit_error_in_data_and_ecc, 217 .verify = double_bit_error_detect, 218 }, 219 { 220 .name = "double-bit-error-in-ecc-detect", 221 .prepare = double_bit_error_in_ecc, 222 .verify = double_bit_error_detect, 223 }, 224}; 225 226static void dump_data_ecc(void *error_data, void *error_ecc, void *correct_data, 227 void *correct_ecc, const size_t size) 228{ 229 pr_info("hexdump of error data:\n"); 230 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4, 231 error_data, size, false); 232 print_hex_dump(KERN_INFO, "hexdump of error ecc: ", 233 DUMP_PREFIX_NONE, 16, 1, error_ecc, 3, false); 234 235 pr_info("hexdump of correct data:\n"); 236 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4, 237 correct_data, size, false); 238 print_hex_dump(KERN_INFO, "hexdump of correct ecc: ", 239 DUMP_PREFIX_NONE, 16, 1, correct_ecc, 3, false); 240} 241 242static int nand_ecc_test_run(const size_t size) 243{ 244 int i; 245 int err = 0; 246 void *error_data; 247 void *error_ecc; 248 void *correct_data; 249 void *correct_ecc; 250 251 error_data = kmalloc(size, GFP_KERNEL); 252 error_ecc = kmalloc(3, GFP_KERNEL); 253 correct_data = kmalloc(size, GFP_KERNEL); 254 correct_ecc = kmalloc(3, GFP_KERNEL); 255 256 if (!error_data || !error_ecc || !correct_data || !correct_ecc) { 257 err = -ENOMEM; 258 goto error; 259 } 260 261 prandom_bytes(correct_data, size); 262 __nand_calculate_ecc(correct_data, size, correct_ecc); 263 264 for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) { 265 nand_ecc_test[i].prepare(error_data, error_ecc, 266 correct_data, correct_ecc, size); 267 err = nand_ecc_test[i].verify(error_data, error_ecc, 268 correct_data, size); 269 270 if (err) { 271 pr_err("not ok - %s-%zd\n", 272 nand_ecc_test[i].name, size); 273 dump_data_ecc(error_data, error_ecc, 274 correct_data, correct_ecc, size); 275 break; 276 } 277 pr_info("ok - %s-%zd\n", 278 nand_ecc_test[i].name, size); 279 280 err = mtdtest_relax(); 281 if (err) 282 break; 283 } 284error: 285 kfree(error_data); 286 kfree(error_ecc); 287 kfree(correct_data); 288 kfree(correct_ecc); 289 290 return err; 291} 292 293#else 294 295static int nand_ecc_test_run(const size_t size) 296{ 297 return 0; 298} 299 300#endif 301 302static int __init ecc_test_init(void) 303{ 304 int err; 305 306 err = nand_ecc_test_run(256); 307 if (err) 308 return err; 309 310 return nand_ecc_test_run(512); 311} 312 313static void __exit ecc_test_exit(void) 314{ 315} 316 317module_init(ecc_test_init); 318module_exit(ecc_test_exit); 319 320MODULE_DESCRIPTION("NAND ECC function test module"); 321MODULE_AUTHOR("Akinobu Mita"); 322MODULE_LICENSE("GPL"); 323