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 single_bit_error_in_data(void *error_data, void *error_ecc, 52 void *correct_data, void *correct_ecc, const size_t size) 53 { 54 single_bit_error_data(error_data, correct_data, size); 55 memcpy(error_ecc, correct_ecc, 3); 56 } 57 58 static int single_bit_error_correct(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 == 1 && !memcmp(correct_data, error_data, size)) 67 return 0; 68 69 return -EINVAL; 70 } 71 72 static const struct nand_ecc_test nand_ecc_test[] = { 73 { 74 .name = "single-bit-error-in-data-correct", 75 .prepare = single_bit_error_in_data, 76 .verify = single_bit_error_correct, 77 }, 78 }; 79 80 static void dump_data_ecc(void *error_data, void *error_ecc, void *correct_data, 81 void *correct_ecc, const size_t size) 82 { 83 pr_info("hexdump of error data:\n"); 84 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4, 85 error_data, size, false); 86 print_hex_dump(KERN_INFO, "hexdump of error ecc: ", 87 DUMP_PREFIX_NONE, 16, 1, error_ecc, 3, false); 88 89 pr_info("hexdump of correct data:\n"); 90 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4, 91 correct_data, size, false); 92 print_hex_dump(KERN_INFO, "hexdump of correct ecc: ", 93 DUMP_PREFIX_NONE, 16, 1, correct_ecc, 3, false); 94 } 95 96 static int nand_ecc_test_run(const size_t size) 97 { 98 int i; 99 int err = 0; 100 void *error_data; 101 void *error_ecc; 102 void *correct_data; 103 void *correct_ecc; 104 105 error_data = kmalloc(size, GFP_KERNEL); 106 error_ecc = kmalloc(3, GFP_KERNEL); 107 correct_data = kmalloc(size, GFP_KERNEL); 108 correct_ecc = kmalloc(3, GFP_KERNEL); 109 110 if (!error_data || !error_ecc || !correct_data || !correct_ecc) { 111 err = -ENOMEM; 112 goto error; 113 } 114 115 get_random_bytes(correct_data, size); 116 __nand_calculate_ecc(correct_data, size, correct_ecc); 117 118 for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) { 119 nand_ecc_test[i].prepare(error_data, error_ecc, 120 correct_data, correct_ecc, size); 121 err = nand_ecc_test[i].verify(error_data, error_ecc, 122 correct_data, size); 123 124 if (err) { 125 pr_err("mtd_nandecctest: not ok - %s-%zd\n", 126 nand_ecc_test[i].name, size); 127 dump_data_ecc(error_data, error_ecc, 128 correct_data, correct_ecc, size); 129 break; 130 } 131 pr_info("mtd_nandecctest: ok - %s-%zd\n", 132 nand_ecc_test[i].name, size); 133 } 134 error: 135 kfree(error_data); 136 kfree(error_ecc); 137 kfree(correct_data); 138 kfree(correct_ecc); 139 140 return err; 141 } 142 143 #else 144 145 static int nand_ecc_test_run(const size_t size) 146 { 147 return 0; 148 } 149 150 #endif 151 152 static int __init ecc_test_init(void) 153 { 154 int err; 155 156 err = nand_ecc_test_run(256); 157 if (err) 158 return err; 159 160 return nand_ecc_test_run(512); 161 } 162 163 static void __exit ecc_test_exit(void) 164 { 165 } 166 167 module_init(ecc_test_init); 168 module_exit(ecc_test_exit); 169 170 MODULE_DESCRIPTION("NAND ECC function test module"); 171 MODULE_AUTHOR("Akinobu Mita"); 172 MODULE_LICENSE("GPL"); 173