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https://github.com/brain-hackers/u-boot-brain
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![Tom Rini](/assets/img/avatar_default.png)
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
197 lines
5.0 KiB
C
197 lines
5.0 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 <linux/bch.h>
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#include <stdlib.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, void *userdata,
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int (*fn)(void *userdata, 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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