drivers/mtd/nand/bbt.c

Source file repositories/reference/linux-study-clean/drivers/mtd/nand/bbt.c

File Facts

System
Linux kernel
Corpus path
drivers/mtd/nand/bbt.c
Extension
.c
Size
3484 bytes
Lines
129
Domain
Driver Families
Bucket
drivers/mtd
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2017 Free Electrons
 *
 * Authors:
 *	Boris Brezillon <boris.brezillon@free-electrons.com>
 *	Peter Pan <peterpandong@micron.com>
 */

#define pr_fmt(fmt)	"nand-bbt: " fmt

#include <linux/mtd/nand.h>
#include <linux/slab.h>

/**
 * nanddev_bbt_init() - Initialize the BBT (Bad Block Table)
 * @nand: NAND device
 *
 * Initialize the in-memory BBT.
 *
 * Return: 0 in case of success, a negative error code otherwise.
 */
int nanddev_bbt_init(struct nand_device *nand)
{
	unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
	unsigned int nblocks = nanddev_neraseblocks(nand);

	nand->bbt.cache = bitmap_zalloc(nblocks * bits_per_block, GFP_KERNEL);
	if (!nand->bbt.cache)
		return -ENOMEM;

	return 0;
}
EXPORT_SYMBOL_GPL(nanddev_bbt_init);

/**
 * nanddev_bbt_cleanup() - Cleanup the BBT (Bad Block Table)
 * @nand: NAND device
 *
 * Undoes what has been done in nanddev_bbt_init()
 */
void nanddev_bbt_cleanup(struct nand_device *nand)
{
	bitmap_free(nand->bbt.cache);
}
EXPORT_SYMBOL_GPL(nanddev_bbt_cleanup);

/**
 * nanddev_bbt_update() - Update a BBT
 * @nand: nand device
 *
 * Update the BBT. Currently a NOP function since on-flash bbt is not yet
 * supported.
 *
 * Return: 0 in case of success, a negative error code otherwise.
 */
int nanddev_bbt_update(struct nand_device *nand)
{
	return 0;
}
EXPORT_SYMBOL_GPL(nanddev_bbt_update);

/**
 * nanddev_bbt_get_block_status() - Return the status of an eraseblock
 * @nand: nand device
 * @entry: the BBT entry
 *
 * Return: a positive number nand_bbt_block_status status or -%ERANGE if @entry
 *	   is bigger than the BBT size.
 */
int nanddev_bbt_get_block_status(const struct nand_device *nand,
				 unsigned int entry)
{
	unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
	unsigned long *pos = nand->bbt.cache +
			     ((entry * bits_per_block) / BITS_PER_LONG);
	unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
	unsigned long status;

	if (entry >= nanddev_neraseblocks(nand))
		return -ERANGE;

	status = pos[0] >> offs;
	if (bits_per_block + offs > BITS_PER_LONG)
		status |= pos[1] << (BITS_PER_LONG - offs);

	return status & GENMASK(bits_per_block - 1, 0);
}
EXPORT_SYMBOL_GPL(nanddev_bbt_get_block_status);

Annotation

Implementation Notes