path: root/drivers/mtd/mtdpart.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Simple MTD partitioning layer
 *
 * Copyright © 2000 Nicolas Pitre <nico@fluxnic.net>
 * Copyright © 2002 Thomas Gleixner <gleixner@linutronix.de>
 * Copyright © 2000-2010 David Woodhouse <dwmw2@infradead.org>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/kmod.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/err.h>
#include <linux/of.h>

#include "mtdcore.h"

/* Our partition linked list */
static LIST_HEAD(mtd_partitions);
static DEFINE_MUTEX(mtd_partitions_mutex);

/**
 * struct mtd_part - our partition node structure
 *
 * @mtd: struct holding partition details
 * @parent: parent mtd - flash device or another partition
 * @offset: partition offset relative to the *flash device*
 */
struct mtd_part {
	struct mtd_info mtd;
	struct mtd_info *parent;
	uint64_t offset;
	struct list_head list;
};

/*
 * Given a pointer to the MTD object in the mtd_part structure, we can retrieve
 * the pointer to that structure.
 */
static inline struct mtd_part *mtd_to_part(const struct mtd_info *mtd)
{
	return container_of(mtd, struct mtd_part, mtd);
}

static u64 part_absolute_offset(struct mtd_info *mtd)
{
	struct mtd_part *part = mtd_to_part(mtd);

	if (!mtd_is_partition(mtd))
		return 0;

	return part_absolute_offset(part->parent) + part->offset;
}

/*
 * MTD methods which simply translate the effective address and pass through
 * to the _real_ device.
 */

static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, u_char *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	struct mtd_ecc_stats stats;
	int res;

	stats = part->parent->ecc_stats;
	res = part->parent->_read(part->parent, from + part->offset, len,
				  retlen, buf);
	if (unlikely(mtd_is_eccerr(res)))
		mtd->ecc_stats.failed +=
			part->parent->ecc_stats.failed - stats.failed;
	else
		mtd->ecc_stats.corrected +=
			part->parent->ecc_stats.corrected - stats.corrected;
	return res;
}

static int part_point(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, void **virt, resource_size_t *phys)
{
	struct mtd_part *part = mtd_to_part(mtd);

	return part->parent->_point(part->parent, from + part->offset, len,
				    retlen, virt, phys);
}

static int part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
	struct mtd_part *part = mtd_to_part(mtd);

	return part->parent->_unpoint(part->parent, from + part->offset, len);
}

static int part_read_oob(struct mtd_info *mtd, loff_t from,
		struct mtd_oob_ops *ops)
{
	struct mtd_part *part = mtd_to_part(mtd);
	struct mtd_ecc_stats stats;
	int res;

	stats = part->parent->ecc_stats;
	res = part->parent->_read_oob(part->parent, from + part->offset, ops);
	if (unlikely(mtd_is_eccerr(res)))
		mtd->ecc_stats.failed +=
			part->parent->ecc_stats.failed - stats.failed;
	else
		mtd->ecc_stats.corrected +=
			part->parent->ecc_stats.corrected - stats.corrected;
	return res;
}

static int part_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
		size_t len, size_t *retlen, u_char *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_read_user_prot_reg(part->parent, from, len,
						 retlen, buf);
}

static int part_get_user_prot_info(struct mtd_info *mtd, size_t len,
				   size_t *retlen, struct otp_info *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_get_user_prot_info(part->parent, len, retlen,
						 buf);
}

static int part_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
		size_t len, size_t *retlen, u_char *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_read_fact_prot_reg(part->parent, from, len,
						 retlen, buf);
}

static int part_get_fact_prot_info(struct mtd_info *mtd, size_t len,
				   size_t *retlen, struct otp_info *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_get_fact_prot_info(part->parent, len, retlen,
						 buf);
}

static int part_write(struct mtd_info *mtd, loff_t to, size_t len,
		size_t *retlen