1 #include <linux/kernel.h> 2 #include <linux/module.h> 3 #include <linux/list.h> 4 #include <linux/random.h> 5 #include <linux/string.h> 6 #include <linux/bitops.h> 7 #include <linux/slab.h> 8 #include <linux/mtd/nand_ecc.h> 9 10 /* 11 * Test the implementation for software ECC 12 * 13 * No actual MTD device is needed, So we don't need to warry about losing 14 * important data by human error. 15 * 16 * This covers possible patterns of corruption which can be reliably corrected 17 * or detected. 18 */ 19 20 #if defined(CONFIG_MTD_NAND) || defined(CONFIG_MTD_NAND_MODULE) 21 22 struct nand_ecc_test { 23 const char *name; 24 void (*prepare)(void *, void *, void *, void *, const size_t); 25 int (*verify)(void *, void *, void *, const size_t); 26 }; 27 28 /* 29 * The reason for this __change_bit_le() instead of __change_bit() is to inject 30 * bit error properly within the region which is not a multiple of 31 * sizeof(unsigned long) on big-endian systems 32 */ 33 #ifdef __LITTLE_ENDIAN 34 #define __change_bit_le(nr, addr) __change_bit(nr, addr) 35 #elif defined(__BIG_ENDIAN) 36 #define __change_bit_le(nr, addr) \ 37 __change_bit((nr) ^ ((BITS_PER_LONG - 1) & ~0x7), addr) 38 #else 39 #error "Unknown byte order" 40 #endif 41 42 static void single_bit_error_data(void *error_data, void *correct_data, 43 size_t size) 44 { 45 unsigned int offset = random32() % (size * BITS_PER_BYTE); 46 47 memcpy(error_data, correct_data, size); 48 __change_bit_le(offset, error_data); 49 } 50 51 static void no_bit_error(void *error_data, void *error_ecc, 52 void *correct_data, void *correct_ecc, const size_t size) 53 { 54 memcpy(error_data, correct_data, size); 55 memcpy(error_ecc, correct_ecc, 3); 56 } 57 58 static int no_bit_error_verify(void *error_data, void *error_ecc, 59 void *correct_data, const size_t size) 60 { 61 unsigned char calc_ecc[3]; 62 int ret; 63 64 __nand_calculate_ecc(error_data, size, calc_ecc); 65 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size); 66 if (ret == 0 && !memcmp(correct_data, error_data, size)) 67 return 0; 68 69 return -EINVAL; 70 } 71 72 static void single_bit_error_in_data(void *error_data, void *error_ecc, 73 void *correct_data, void *correct_ecc, const size_t size) 74 { 75 single_bit_error_data(error_data, correct_data, size); 76 memcpy(error_ecc, correct_ecc, 3); 77 } 78 79 static int single_bit_error_correct(void *error_data, void *error_ecc, 80 void *correct_data, const size_t size) 81 { 82 unsigned char calc_ecc[3]; 83 int ret; 84 85 __nand_calculate_ecc(error_data, size, calc_ecc); 86 ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size); 87 if (ret == 1 && !memcmp(correct_data, error_data, size)) 88 return 0; 89 90 return -EINVAL; 91 } 92 93 static const struct nand_ecc_test nand_ecc_test[] = { 94 { 95 .name = "no-bit-error", 96 .prepare = no_bit_error, 97 .verify = no_bit_error_verify, 98 }, 99 { 100 .name = "single-bit-error-in-data-correct", 101 .prepare = single_bit_error_in_data, 102 .verify = single_bit_error_correct, 103 }, 104 }; 105 106 static void dump_data_ecc(void *error_data, void *error_ecc, void *correct_data, 107 void *correct_ecc, const size_t size) 108 { 109 pr_info("hexdump of error data:\n"); 110 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4, 111 error_data, size, false); 112 print_hex_dump(KERN_INFO, "hexdump of error ecc: ", 113 DUMP_PREFIX_NONE, 16, 1, error_ecc, 3, false); 114 115 pr_info("hexdump of correct data:\n"); 116 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4, 117 correct_data, size, false); 118 print_hex_dump(KERN_INFO, "hexdump of correct ecc: ", 119 DUMP_PREFIX_NONE, 16, 1, correct_ecc, 3, false); 120 } 121 122 static int nand_ecc_test_run(const size_t size) 123 { 124 int i; 125 int err = 0; 126 void *error_data; 127 void *error_ecc; 128 void *correct_data; 129 void *correct_ecc; 130 131 error_data = kmalloc(size, GFP_KERNEL); 132 error_ecc = kmalloc(3, GFP_KERNEL); 133 correct_data = kmalloc(size, GFP_KERNEL); 134 correct_ecc = kmalloc(3, GFP_KERNEL); 135 136 if (!error_data || !error_ecc || !correct_data || !correct_ecc) { 137 err = -ENOMEM; 138 goto error; 139 } 140 141 get_random_bytes(correct_data, size); 142 __nand_calculate_ecc(correct_data, size, correct_ecc); 143 144 for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) { 145 nand_ecc_test[i].prepare(error_data, error_ecc, 146 correct_data, correct_ecc, size); 147 err = nand_ecc_test[i].verify(error_data, error_ecc, 148 correct_data, size); 149 150 if (err) { 151 pr_err("mtd_nandecctest: not ok - %s-%zd\n", 152 nand_ecc_test[i].name, size); 153 dump_data_ecc(error_data, error_ecc, 154 correct_data, correct_ecc, size); 155 break; 156 } 157 pr_info("mtd_nandecctest: ok - %s-%zd\n", 158 nand_ecc_test[i].name, size); 159 } 160 error: 161 kfree(error_data); 162 kfree(error_ecc); 163 kfree(correct_data); 164 kfree(correct_ecc); 165 166 return err; 167 } 168 169 #else 170 171 static int nand_ecc_test_run(const size_t size) 172 { 173 return 0; 174 } 175 176 #endif 177 178 static int __init ecc_test_init(void) 179 { 180 int err; 181 182 err = nand_ecc_test_run(256); 183 if (err) 184 return err; 185 186 return nand_ecc_test_run(512); 187 } 188 189 static void __exit ecc_test_exit(void) 190 { 191 } 192 193 module_init(ecc_test_init); 194 module_exit(ecc_test_exit); 195 196 MODULE_DESCRIPTION("NAND ECC function test module"); 197 MODULE_AUTHOR("Akinobu Mita"); 198 MODULE_LICENSE("GPL"); 199