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![Sebastian Reichel](/assets/img/avatar_default.png)
This separates the I2C specific code from the generic GE vital product data code, so that the generic parts can be used on hardware with VPD stored in SPI flash memory. Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
238 lines
5.7 KiB
C
238 lines
5.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright 2016 General Electric Company
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*/
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#include "vpd_reader.h"
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#include <malloc.h>
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#include <i2c.h>
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#include <linux/bch.h>
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#include <stdlib.h>
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#include <dm/uclass.h>
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#include <i2c_eeprom.h>
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#include <hexdump.h>
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/* BCH configuration */
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const struct {
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int header_ecc_capability_bits;
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int data_ecc_capability_bits;
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unsigned int prim_poly;
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struct {
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int min;
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int max;
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} galois_field_order;
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} bch_configuration = {
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.header_ecc_capability_bits = 4,
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.data_ecc_capability_bits = 16,
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.prim_poly = 0,
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.galois_field_order = {
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.min = 5,
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.max = 15,
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},
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};
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static int calculate_galois_field_order(size_t source_length)
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{
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int gfo = bch_configuration.galois_field_order.min;
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for (; gfo < bch_configuration.galois_field_order.max &&
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((((1 << gfo) - 1) - ((int)source_length * 8)) < 0);
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gfo++) {
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}
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if (gfo == bch_configuration.galois_field_order.max)
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return -1;
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return gfo + 1;
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}
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static int verify_bch(int ecc_bits, unsigned int prim_poly, u8 *data,
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size_t data_length, const u8 *ecc, size_t ecc_length)
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{
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int gfo = calculate_galois_field_order(data_length);
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if (gfo < 0)
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return -1;
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struct bch_control *bch = init_bch(gfo, ecc_bits, prim_poly);
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if (!bch)
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return -1;
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if (bch->ecc_bytes != ecc_length) {
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free_bch(bch);
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return -1;
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}
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unsigned int *errloc = (unsigned int *)calloc(data_length,
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sizeof(unsigned int));
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int errors = decode_bch(bch, data, data_length, ecc, NULL, NULL,
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errloc);
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free_bch(bch);
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if (errors < 0) {
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free(errloc);
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return -1;
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}
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if (errors > 0) {
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for (int n = 0; n < errors; n++) {
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if (errloc[n] >= 8 * data_length) {
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/*
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* n-th error located in ecc (no need for data
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* correction)
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*/
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} else {
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/* n-th error located in data */
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data[errloc[n] / 8] ^= 1 << (errloc[n] % 8);
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}
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}
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}
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free(errloc);
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return 0;
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}
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static const int ID;
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static const int LEN = 1;
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static const int VER = 2;
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static const int TYP = 3;
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static const int BLOCK_SIZE = 4;
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static const u8 HEADER_BLOCK_ID;
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static const u8 HEADER_BLOCK_LEN = 18;
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static const u32 HEADER_BLOCK_MAGIC = 0xca53ca53;
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static const size_t HEADER_BLOCK_VERIFY_LEN = 14;
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static const size_t HEADER_BLOCK_ECC_OFF = 14;
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static const size_t HEADER_BLOCK_ECC_LEN = 4;
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static const u8 ECC_BLOCK_ID = 0xFF;
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int vpd_reader(size_t size, u8 *data, struct vpd_cache *userdata,
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int (*fn)(struct vpd_cache *, u8 id, u8 version, u8 type,
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size_t size, u8 const *data))
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{
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if (size < HEADER_BLOCK_LEN || !data || !fn)
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return -EINVAL;
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/*
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* +--------------------+----------------+--//--+--------------------+
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* | header block | data block | ... | ecc block |
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* +--------------------+----------------+--//--+--------------------+
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* : : :
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* +------+-------+-----+ +------+-------------+
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* | id | magic | ecc | | ... | ecc |
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* | len | off | | +------+-------------+
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* | ver | size | | :
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* | type | | | :
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* +------+-------+-----+ :
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* : : : :
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* <----- [1] ----> <--------- [2] --------->
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*
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* Repair (if necessary) the contents of header block [1] by using a
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* 4 byte ECC located at the end of the header block. A successful
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* return value means that we can trust the header.
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*/
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int ret = verify_bch(bch_configuration.header_ecc_capability_bits,
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bch_configuration.prim_poly, data,
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HEADER_BLOCK_VERIFY_LEN,
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&data[HEADER_BLOCK_ECC_OFF], HEADER_BLOCK_ECC_LEN);
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if (ret < 0)
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return ret;
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/* Validate header block { id, length, version, type }. */
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if (data[ID] != HEADER_BLOCK_ID || data[LEN] != HEADER_BLOCK_LEN ||
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data[VER] != 0 || data[TYP] != 0 ||
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ntohl(*(u32 *)(&data[4])) != HEADER_BLOCK_MAGIC)
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return -EINVAL;
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u32 offset = ntohl(*(u32 *)(&data[8]));
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u16 size_bits = ntohs(*(u16 *)(&data[12]));
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/* Check that ECC header fits. */
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if (offset + 3 >= size)
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return -EINVAL;
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/* Validate ECC block. */
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u8 *ecc = &data[offset];
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if (ecc[ID] != ECC_BLOCK_ID || ecc[LEN] < BLOCK_SIZE ||
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ecc[LEN] + offset > size ||
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ecc[LEN] - BLOCK_SIZE != size_bits / 8 || ecc[VER] != 1 ||
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ecc[TYP] != 1)
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return -EINVAL;
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/*
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* Use the header block to locate the ECC block and verify the data
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* blocks [2] against the ecc block ECC.
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*/
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ret = verify_bch(bch_configuration.data_ecc_capability_bits,
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bch_configuration.prim_poly, &data[data[LEN]],
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offset - data[LEN], &data[offset + BLOCK_SIZE],
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ecc[LEN] - BLOCK_SIZE);
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if (ret < 0)
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return ret;
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/* Stop after ECC. Ignore possible zero padding. */
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size = offset;
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for (;;) {
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/* Move to next block. */
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size -= data[LEN];
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data += data[LEN];
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if (size == 0) {
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/* Finished iterating through blocks. */
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return 0;
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}
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if (size < BLOCK_SIZE || data[LEN] < BLOCK_SIZE) {
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/* Not enough data for a header, or short header. */
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return -EINVAL;
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}
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ret = fn(userdata, data[ID], data[VER], data[TYP],
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data[LEN] - BLOCK_SIZE, &data[BLOCK_SIZE]);
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if (ret)
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return ret;
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}
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}
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int read_i2c_vpd(struct vpd_cache *cache,
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int (*process_block)(struct vpd_cache *, u8 id, u8 version,
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u8 type, size_t size, u8 const *data))
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{
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struct udevice *dev;
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int ret;
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u8 *data;
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int size;
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ret = uclass_get_device_by_name(UCLASS_I2C_EEPROM, "vpd", &dev);
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if (ret)
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return ret;
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size = i2c_eeprom_size(dev);
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if (size < 0) {
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printf("Unable to get size of eeprom: %d\n", ret);
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return ret;
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}
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data = malloc(size);
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if (!data)
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return -ENOMEM;
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ret = i2c_eeprom_read(dev, 0, data, size);
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if (ret) {
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free(data);
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return ret;
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}
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ret = vpd_reader(size, data, cache, process_block);
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free(data);
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return ret;
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}
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