1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (c) 2017 Free Electrons
  4 *
  5 * Authors:
  6 *	Boris Brezillon <boris.brezillon@free-electrons.com>
  7 *	Peter Pan <peterpandong@micron.com>
  8 */
  9
 10#define pr_fmt(fmt)	"nand-bbt: " fmt
 11
 12#include <linux/mtd/nand.h>
 13#include <linux/slab.h>
 14
 15/**
 16 * nanddev_bbt_init() - Initialize the BBT (Bad Block Table)
 17 * @nand: NAND device
 18 *
 19 * Initialize the in-memory BBT.
 20 *
 21 * Return: 0 in case of success, a negative error code otherwise.
 22 */
 23int nanddev_bbt_init(struct nand_device *nand)
 24{
 25	unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
 26	unsigned int nblocks = nanddev_neraseblocks(nand);
 27	unsigned int nwords = DIV_ROUND_UP(nblocks * bits_per_block,
 28					   BITS_PER_LONG);
 29
 30	nand->bbt.cache = kcalloc(nwords, sizeof(*nand->bbt.cache),
 31				  GFP_KERNEL);
 32	if (!nand->bbt.cache)
 33		return -ENOMEM;
 34
 35	return 0;
 36}
 37EXPORT_SYMBOL_GPL(nanddev_bbt_init);
 38
 39/**
 40 * nanddev_bbt_cleanup() - Cleanup the BBT (Bad Block Table)
 41 * @nand: NAND device
 42 *
 43 * Undoes what has been done in nanddev_bbt_init()
 44 */
 45void nanddev_bbt_cleanup(struct nand_device *nand)
 46{
 47	kfree(nand->bbt.cache);
 48}
 49EXPORT_SYMBOL_GPL(nanddev_bbt_cleanup);
 50
 51/**
 52 * nanddev_bbt_update() - Update a BBT
 53 * @nand: nand device
 54 *
 55 * Update the BBT. Currently a NOP function since on-flash bbt is not yet
 56 * supported.
 57 *
 58 * Return: 0 in case of success, a negative error code otherwise.
 59 */
 60int nanddev_bbt_update(struct nand_device *nand)
 61{
 62	return 0;
 63}
 64EXPORT_SYMBOL_GPL(nanddev_bbt_update);
 65
 66/**
 67 * nanddev_bbt_get_block_status() - Return the status of an eraseblock
 68 * @nand: nand device
 69 * @entry: the BBT entry
 70 *
 71 * Return: a positive number nand_bbt_block_status status or -%ERANGE if @entry
 72 *	   is bigger than the BBT size.
 73 */
 74int nanddev_bbt_get_block_status(const struct nand_device *nand,
 75				 unsigned int entry)
 76{
 77	unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
 78	unsigned long *pos = nand->bbt.cache +
 79			     ((entry * bits_per_block) / BITS_PER_LONG);
 80	unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
 81	unsigned long status;
 82
 83	if (entry >= nanddev_neraseblocks(nand))
 84		return -ERANGE;
 85
 86	status = pos[0] >> offs;
 87	if (bits_per_block + offs > BITS_PER_LONG)
 88		status |= pos[1] << (BITS_PER_LONG - offs);
 89
 90	return status & GENMASK(bits_per_block - 1, 0);
 91}
 92EXPORT_SYMBOL_GPL(nanddev_bbt_get_block_status);
 93
 94/**
 95 * nanddev_bbt_set_block_status() - Update the status of an eraseblock in the
 96 *				    in-memory BBT
 97 * @nand: nand device
 98 * @entry: the BBT entry to update
 99 * @status: the new status
100 *
101 * Update an entry of the in-memory BBT. If you want to push the updated BBT
102 * the NAND you should call nanddev_bbt_update().
103 *
104 * Return: 0 in case of success or -%ERANGE if @entry is bigger than the BBT
105 *	   size.
106 */
107int nanddev_bbt_set_block_status(struct nand_device *nand, unsigned int entry,
108				 enum nand_bbt_block_status status)
109{
110	unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
111	unsigned long *pos = nand->bbt.cache +
112			     ((entry * bits_per_block) / BITS_PER_LONG);
113	unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
114	unsigned long val = status & GENMASK(bits_per_block - 1, 0);
115
116	if (entry >= nanddev_neraseblocks(nand))
117		return -ERANGE;
118
119	pos[0] &= ~GENMASK(offs + bits_per_block - 1, offs);
120	pos[0] |= val << offs;
121
122	if (bits_per_block + offs > BITS_PER_LONG) {
123		unsigned int rbits = bits_per_block + offs - BITS_PER_LONG;
124
125		pos[1] &= ~GENMASK(rbits - 1, 0);
126		pos[1] |= val >> rbits;
127	}
128
129	return 0;
130}
131EXPORT_SYMBOL_GPL(nanddev_bbt_set_block_status);