uhd/mpm/tools/tlv_eeprom/tlv_eeprom.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2019 Ettus Research, a National Instruments Brand
 */

#include "tlv_eeprom.h"
#include <string.h>

struct tlv_eeprom* tlv_eeprom_init(void* data)
{
    struct tlv_eeprom* e = data;

    return e;
}

void tlv_eeprom_seal(struct tlv_eeprom* e, uint32_t magic, size_t len)
{
    e->magic = magic;
    e->size  = len;
    e->crc   = tlv_eeprom_crc(e);
}

int tlv_eeprom_validate(const struct tlv_eeprom* e, uint32_t magic)
{
    uint32_t crc;

    if (e->magic != magic)
        return -1;

    if (e->size > TLV_EEPROM_SIZE)
        return -2;

    crc = tlv_eeprom_crc(e);
    if (e->crc != crc)
        return -3;

    return 0;
}

struct tlv
{
    uint8_t tag;
    uint8_t len;
    uint8_t val[0];
};


static inline const struct tlv* tlv_next(const struct tlv* tlv, const void* end)
{
    const void* p = &tlv->val;

    p += tlv->len;
    if (p >= end)
        return NULL;
    return p;
}

static inline const struct tlv* tlv_find(
    const struct tlv* tlv, const void* end, uint8_t tag)
{
    do {
        if (tlv->tag == tag)
            break;
    } while ((tlv = tlv_next(tlv, end)));

    return tlv;
}

void tlv_for_each(
    const void* buf, size_t bufsz, void (*fn)(uint8_t tag, uint8_t len, const void* val))
{
    const struct tlv* tlv = buf;

    do {
        fn(tlv->tag, tlv->len, tlv->val);
    } while ((tlv = tlv_next(tlv, buf + bufsz)));
}

const void* tlv_lookup(const void* buf, size_t bufsz, uint8_t tag)
{
    const struct tlv* tlv;

    tlv = tlv_find(buf, buf + bufsz, tag);
    if (!tlv)
        return tlv;

    return tlv->val;
}

size_t tlv_write(void* buf, uint8_t tag, uint8_t len, const void* val)
{
    struct tlv* tlv = buf;

    tlv->tag = tag;
    tlv->len = len;
    memcpy(tlv->val, val, len);

    return sizeof(*tlv) + len;
}