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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2019 Ettus Research, a National Instruments Brand
*/
#pragma once
#include <stddef.h>
#include <stdint.h>
/*
* All eeproms on this platform are 256 bytes long
*/
#define TLV_EEPROM_SIZE (256)
/**
* struct tlv_eeprom - structure describing the eeprom layout
*
* NOTE: All fields stored to eeprom are little endian, and this library
* assumes the processor running it is also little endian (i.e., no endianess
* conversion is performed).
*
* @magic: magic to identify the eeprom
* @crc: crc over the size field plus the following size bytes
* @size: size of remaining data in bytes
* @tlv: up to 244 bytes of tlv data
*/
struct tlv_eeprom {
uint32_t magic;
uint32_t crc;
uint32_t size;
uint8_t tlv[TLV_EEPROM_SIZE - 3 * sizeof(uint32_t)];
} __attribute__((packed));
/**
* tlv_eeprom_init - create tlv_eeprom from backing store
* @data: backing store, which must be at least TLV_EEPROM_SIZE bytes
*/
struct tlv_eeprom *tlv_eeprom_init(void *data);
/**
* tlv_eeprom_validate - check if an eeprom is valid
* @e: eeprom to validate
* @magic: expected magic for this eeprom
*
* Checks to see whether the eeprom is valid. This validates the magic, the
* size, and the CRC of the data.
*
* Return: zero on success, -1 for a magic mismatch, -2 for an invalid size, -3
* for an invalid crc
*/
int tlv_eeprom_validate(const struct tlv_eeprom *e, uint32_t magic);
/**
* tlv_eeprom_seal - seal an eeprom
* @e: eeprom to seal
* @magic: magic to use for this eeprom
* @len: size of tlv data stored in eeprom
*
* Updates the magic, size, and crc of the eeprom. This should be called prior
* to writing an eeprom.
*/
void tlv_eeprom_seal(struct tlv_eeprom *e, uint32_t magic, size_t len);
/*
* tlv_eeprom_crc - return the CRC for the eeprom
* @eeprom: eeprom to compute the crc
*
* Note: e->size must be valid!
*
* Returns: the crc
*/
extern uint32_t tlv_eeprom_crc(const struct tlv_eeprom *e);
/**
* tlv_write - writes a tlv tuple to the buffer
* @buf: buffer to write to
* @tag: tag for this data
* @len: length of value
* @val: value to write
*
* Return: number of bytes written to buffer, including tag and size
*/
size_t tlv_write(void *buf, uint8_t tag, uint8_t len, const void *val);
/**
* tlv_lookup - lookup the value associated with a tag
* @buf: buffer containing tlv data
* @bufsz: size of buffer containing tlv data
* @tag: tag to lookup
*
* Return: pointer to value at tag, or NULL if tag was not found
*/
const void *tlv_lookup(const void *buf, size_t bufsz, uint8_t tag);
/*
* tlv_for_each - call fn for each value in buffer
* @buf: buffer containing tlv data
* @bufsz: size of buffer containing tlv data
* @fn: function to invoke for each value
*/
void tlv_for_each(const void *buf, size_t bufsz,
void (*fn)(uint8_t tag, uint8_t len, const void *val));
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