drivers/mtd/nand/bbt.c

   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  */
  23 int 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
  28         nand->bbt.cache = bitmap_zalloc(nblocks * bits_per_block, GFP_KERNEL);
  29         if (!nand->bbt.cache)
  30                 return -ENOMEM;
  31
  32         return 0;
  33 }
  34 EXPORT_SYMBOL_GPL(nanddev_bbt_init);
  35
  36 /**
  37  * nanddev_bbt_cleanup() - Cleanup the BBT (Bad Block Table)
  38  * @nand: NAND device
  39  *
  40  * Undoes what has been done in nanddev_bbt_init()
  41  */
  42 void nanddev_bbt_cleanup(struct nand_device *nand)
  43 {
  44         bitmap_free(nand->bbt.cache);
  45 }
  46 EXPORT_SYMBOL_GPL(nanddev_bbt_cleanup);
  47
  48 /**
  49  * nanddev_bbt_update() - Update a BBT
  50  * @nand: nand device
  51  *
  52  * Update the BBT. Currently a NOP function since on-flash bbt is not yet
  53  * supported.
  54  *
  55  * Return: 0 in case of success, a negative error code otherwise.
  56  */
  57 int nanddev_bbt_update(struct nand_device *nand)
  58 {
  59         return 0;
  60 }
  61 EXPORT_SYMBOL_GPL(nanddev_bbt_update);
  62
  63 /**
  64  * nanddev_bbt_get_block_status() - Return the status of an eraseblock
  65  * @nand: nand device
  66  * @entry: the BBT entry
  67  *
  68  * Return: a positive number nand_bbt_block_status status or -%ERANGE if @entry
  69  *         is bigger than the BBT size.
  70  */
  71 int nanddev_bbt_get_block_status(const struct nand_device *nand,
  72                                  unsigned int entry)
  73 {
  74         unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
  75         unsigned long *pos = nand->bbt.cache +
  76                              ((entry * bits_per_block) / BITS_PER_LONG);
  77         unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
  78         unsigned long status;
  79
  80         if (entry >= nanddev_neraseblocks(nand))
  81                 return -ERANGE;
  82
  83         status = pos[0] >> offs;
  84         if (bits_per_block + offs > BITS_PER_LONG)
  85                 status |= pos[1] << (BITS_PER_LONG - offs);
  86
  87         return status & GENMASK(bits_per_block - 1, 0);
  88 }
  89 EXPORT_SYMBOL_GPL(nanddev_bbt_get_block_status);
  90
  91 /**
  92  * nanddev_bbt_set_block_status() - Update the status of an eraseblock in the
  93  *                                  in-memory BBT
  94  * @nand: nand device
  95  * @entry: the BBT entry to update
  96  * @status: the new status
  97  *
  98  * Update an entry of the in-memory BBT. If you want to push the updated BBT
  99  * the NAND you should call nanddev_bbt_update().
 100  *
 101  * Return: 0 in case of success or -%ERANGE if @entry is bigger than the BBT
 102  *         size.
 103  */
 104 int nanddev_bbt_set_block_status(struct nand_device *nand, unsigned int entry,
 105                                  enum nand_bbt_block_status status)
 106 {
 107         unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
 108         unsigned long *pos = nand->bbt.cache +
 109                              ((entry * bits_per_block) / BITS_PER_LONG);
 110         unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
 111         unsigned long val = status & GENMASK(bits_per_block - 1, 0);
 112
 113         if (entry >= nanddev_neraseblocks(nand))
 114                 return -ERANGE;
 115
 116         pos[0] &= ~GENMASK(offs + bits_per_block - 1, offs);
 117         pos[0] |= val << offs;
 118
 119         if (bits_per_block + offs > BITS_PER_LONG) {
 120                 unsigned int rbits = bits_per_block + offs - BITS_PER_LONG;
 121
 122                 pos[1] &= ~GENMASK(rbits - 1, 0);
 123                 pos[1] |= val >> (bits_per_block - rbits);
 124         }
 125
 126         return 0;
 127 }
 128 EXPORT_SYMBOL_GPL(nanddev_bbt_set_block_status);