1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright 2016 General Electric Company
6 #include "vpd_reader.h"
11 #include <dm/uclass.h>
12 #include <i2c_eeprom.h>
15 /* BCH configuration */
18 int header_ecc_capability_bits;
19 int data_ecc_capability_bits;
20 unsigned int prim_poly;
25 } bch_configuration = {
26 .header_ecc_capability_bits = 4,
27 .data_ecc_capability_bits = 16,
29 .galois_field_order = {
35 static int calculate_galois_field_order(size_t source_length)
37 int gfo = bch_configuration.galois_field_order.min;
39 for (; gfo < bch_configuration.galois_field_order.max &&
40 ((((1 << gfo) - 1) - ((int)source_length * 8)) < 0);
44 if (gfo == bch_configuration.galois_field_order.max)
50 static int verify_bch(int ecc_bits, unsigned int prim_poly, u8 *data,
51 size_t data_length, const u8 *ecc, size_t ecc_length)
53 int gfo = calculate_galois_field_order(data_length);
58 struct bch_control *bch = init_bch(gfo, ecc_bits, prim_poly);
63 if (bch->ecc_bytes != ecc_length) {
68 unsigned int *errloc = (unsigned int *)calloc(data_length,
69 sizeof(unsigned int));
70 int errors = decode_bch(bch, data, data_length, ecc, NULL, NULL,
80 for (int n = 0; n < errors; n++) {
81 if (errloc[n] >= 8 * data_length) {
83 * n-th error located in ecc (no need for data
87 /* n-th error located in data */
88 data[errloc[n] / 8] ^= 1 << (errloc[n] % 8);
98 static const int LEN = 1;
99 static const int VER = 2;
100 static const int TYP = 3;
101 static const int BLOCK_SIZE = 4;
103 static const u8 HEADER_BLOCK_ID;
104 static const u8 HEADER_BLOCK_LEN = 18;
105 static const u32 HEADER_BLOCK_MAGIC = 0xca53ca53;
106 static const size_t HEADER_BLOCK_VERIFY_LEN = 14;
107 static const size_t HEADER_BLOCK_ECC_OFF = 14;
108 static const size_t HEADER_BLOCK_ECC_LEN = 4;
110 static const u8 ECC_BLOCK_ID = 0xFF;
112 static int vpd_reader(size_t size, u8 *data, struct vpd_cache *userdata,
113 int (*fn)(struct vpd_cache *, u8 id, u8 version, u8 type,
114 size_t size, u8 const *data))
116 if (size < HEADER_BLOCK_LEN || !data || !fn)
120 * +--------------------+----------------+--//--+--------------------+
121 * | header block | data block | ... | ecc block |
122 * +--------------------+----------------+--//--+--------------------+
124 * +------+-------+-----+ +------+-------------+
125 * | id | magic | ecc | | ... | ecc |
126 * | len | off | | +------+-------------+
129 * +------+-------+-----+ :
131 * <----- [1] ----> <--------- [2] --------->
133 * Repair (if necessary) the contents of header block [1] by using a
134 * 4 byte ECC located at the end of the header block. A successful
135 * return value means that we can trust the header.
137 int ret = verify_bch(bch_configuration.header_ecc_capability_bits,
138 bch_configuration.prim_poly, data,
139 HEADER_BLOCK_VERIFY_LEN,
140 &data[HEADER_BLOCK_ECC_OFF], HEADER_BLOCK_ECC_LEN);
144 /* Validate header block { id, length, version, type }. */
145 if (data[ID] != HEADER_BLOCK_ID || data[LEN] != HEADER_BLOCK_LEN ||
146 data[VER] != 0 || data[TYP] != 0 ||
147 ntohl(*(u32 *)(&data[4])) != HEADER_BLOCK_MAGIC)
150 u32 offset = ntohl(*(u32 *)(&data[8]));
151 u16 size_bits = ntohs(*(u16 *)(&data[12]));
153 /* Check that ECC header fits. */
154 if (offset + 3 >= size)
157 /* Validate ECC block. */
158 u8 *ecc = &data[offset];
160 if (ecc[ID] != ECC_BLOCK_ID || ecc[LEN] < BLOCK_SIZE ||
161 ecc[LEN] + offset > size ||
162 ecc[LEN] - BLOCK_SIZE != size_bits / 8 || ecc[VER] != 1 ||
167 * Use the header block to locate the ECC block and verify the data
168 * blocks [2] against the ecc block ECC.
170 ret = verify_bch(bch_configuration.data_ecc_capability_bits,
171 bch_configuration.prim_poly, &data[data[LEN]],
172 offset - data[LEN], &data[offset + BLOCK_SIZE],
173 ecc[LEN] - BLOCK_SIZE);
177 /* Stop after ECC. Ignore possible zero padding. */
181 /* Move to next block. */
186 /* Finished iterating through blocks. */
190 if (size < BLOCK_SIZE || data[LEN] < BLOCK_SIZE) {
191 /* Not enough data for a header, or short header. */
195 ret = fn(userdata, data[ID], data[VER], data[TYP],
196 data[LEN] - BLOCK_SIZE, &data[BLOCK_SIZE]);
202 int read_vpd(struct vpd_cache *cache,
203 int (*process_block)(struct vpd_cache *, u8 id, u8 version,
204 u8 type, size_t size, u8 const *data))
211 ret = uclass_get_device_by_name(UCLASS_I2C_EEPROM, "vpd", &dev);
215 size = i2c_eeprom_size(dev);
217 printf("Unable to get size of eeprom: %d\n", ret);
225 ret = i2c_eeprom_read(dev, 0, data, size);
231 ret = vpd_reader(size, data, cache, process_block);