linux/drivers/mtd/spi-nor/otp.c

// SPDX-License-Identifier: GPL-2.0
/*
 * OTP support for SPI NOR flashes
 *
 * Copyright (C) 2021 Michael Walle <[email protected]>
 */

#include <linux/log2.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/spi-nor.h>

#include "core.h"

#define spi_nor_otp_region_len(nor) …
#define spi_nor_otp_n_regions(nor) …

/**
 * spi_nor_otp_read_secr() - read security register
 * @nor:	pointer to 'struct spi_nor'
 * @addr:       offset to read from
 * @len:        number of bytes to read
 * @buf:        pointer to dst buffer
 *
 * Read a security register by using the SPINOR_OP_RSECR commands.
 *
 * In Winbond/GigaDevice datasheets the term "security register" stands for
 * an one-time-programmable memory area, consisting of multiple bytes (usually
 * 256). Thus one "security register" maps to one OTP region.
 *
 * This method is used on GigaDevice and Winbond flashes.
 *
 * Please note, the read must not span multiple registers.
 *
 * Return: number of bytes read successfully, -errno otherwise
 */
int spi_nor_otp_read_secr(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf)
{ … }

/**
 * spi_nor_otp_write_secr() - write security register
 * @nor:        pointer to 'struct spi_nor'
 * @addr:       offset to write to
 * @len:        number of bytes to write
 * @buf:        pointer to src buffer
 *
 * Write a security register by using the SPINOR_OP_PSECR commands.
 *
 * For more information on the term "security register", see the documentation
 * of spi_nor_otp_read_secr().
 *
 * This method is used on GigaDevice and Winbond flashes.
 *
 * Please note, the write must not span multiple registers.
 *
 * Return: number of bytes written successfully, -errno otherwise
 */
int spi_nor_otp_write_secr(struct spi_nor *nor, loff_t addr, size_t len,
			   const u8 *buf)
{ … }

/**
 * spi_nor_otp_erase_secr() - erase a security register
 * @nor:        pointer to 'struct spi_nor'
 * @addr:       offset of the security register to be erased
 *
 * Erase a security register by using the SPINOR_OP_ESECR command.
 *
 * For more information on the term "security register", see the documentation
 * of spi_nor_otp_read_secr().
 *
 * This method is used on GigaDevice and Winbond flashes.
 *
 * Return: 0 on success, -errno otherwise
 */
int spi_nor_otp_erase_secr(struct spi_nor *nor, loff_t addr)
{ … }

static int spi_nor_otp_lock_bit_cr(unsigned int region)
{ … }

/**
 * spi_nor_otp_lock_sr2() - lock the OTP region
 * @nor:        pointer to 'struct spi_nor'
 * @region:     OTP region
 *
 * Lock the OTP region by writing the status register-2. This method is used on
 * GigaDevice and Winbond flashes.
 *
 * Return: 0 on success, -errno otherwise.
 */
int spi_nor_otp_lock_sr2(struct spi_nor *nor, unsigned int region)
{ … }

/**
 * spi_nor_otp_is_locked_sr2() - get the OTP region lock status
 * @nor:        pointer to 'struct spi_nor'
 * @region:     OTP region
 *
 * Retrieve the OTP region lock bit by reading the status register-2. This
 * method is used on GigaDevice and Winbond flashes.
 *
 * Return: 0 on success, -errno otherwise.
 */
int spi_nor_otp_is_locked_sr2(struct spi_nor *nor, unsigned int region)
{ … }

static loff_t spi_nor_otp_region_start(const struct spi_nor *nor, unsigned int region)
{ … }

static size_t spi_nor_otp_size(struct spi_nor *nor)
{ … }

/* Translate the file offsets from and to OTP regions. */
static loff_t spi_nor_otp_region_to_offset(struct spi_nor *nor, unsigned int region)
{ … }

static unsigned int spi_nor_otp_offset_to_region(struct spi_nor *nor, loff_t ofs)
{ … }

static int spi_nor_mtd_otp_info(struct mtd_info *mtd, size_t len,
				size_t *retlen, struct otp_info *buf)
{ … }

static int spi_nor_mtd_otp_range_is_locked(struct spi_nor *nor, loff_t ofs,
					   size_t len)
{ … }

static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs,
				      size_t total_len, size_t *retlen,
				      const u8 *buf, bool is_write)
{ … }

static int spi_nor_mtd_otp_read(struct mtd_info *mtd, loff_t from, size_t len,
				size_t *retlen, u8 *buf)
{ … }

static int spi_nor_mtd_otp_write(struct mtd_info *mtd, loff_t to, size_t len,
				 size_t *retlen, const u8 *buf)
{ … }

static int spi_nor_mtd_otp_erase(struct mtd_info *mtd, loff_t from, size_t len)
{ … }

static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
{ … }

void spi_nor_set_mtd_otp_ops(struct spi_nor *nor)
{ … }