target/linux/sunxi/patches-4.1/113-mtd-nand-add-pst.patch

   1 From bec69bb8e85151729014d859106dcc3fe652b1d4 Mon Sep 17 00:00:00 2001
   2 From: Boris BREZILLON <boris.brezillon@free-electrons.com>
   3 Date: Mon, 28 Jul 2014 14:45:40 +0200
   4 Subject: [PATCH] mtd: nand: Add page status table (pst)
   5
   6 Page status table is an byte array storing pages status.
   7 It defines 3 status:
   8  - unknown: the page has not been read yet and we do not know its current
   9    state
  10  - empty: the page contains only FFs
  11  - filled: the page has been filled with data
  12
  13 Care must be taken: an empty page does not mean it can be written, because
  14 it might have already been written with only FFs.
  15
  16 These page status are useful to check wether the controller should try to
  17 correct errors (using ECC) or a derandomize data (using a randomizer
  18 block).
  19
  20 Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
  21 Signed-off-by: Hans de Goede <hdegoede@redhat.com>
  22 ---
  23  drivers/mtd/nand/nand_base.c | 154 +++++++++++++++++++++++++++++++++++++++++++
  24  include/linux/mtd/nand.h     |  21 ++++++
  25  2 files changed, 175 insertions(+)
  26
  27 diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
  28 index a30b67f..8a5d12e 100644
  29 --- a/drivers/mtd/nand/nand_base.c
  30 +++ b/drivers/mtd/nand/nand_base.c
  31 @@ -1102,6 +1102,138 @@ int nand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
  32  EXPORT_SYMBOL(nand_lock);
  33
  34  /**
  35 + * nand_page_is_empty - check wether a NAND page contains only FFs
  36 + * @mtd:       mtd info
  37 + * @data:      data buffer
  38 + * @oob:       oob buffer
  39 + *
  40 + * Reads the data stored in the databuf buffer and check if it contains only
  41 + * FFs.
  42 + *
  43 + * Return true if it does else return false.
  44 + */
  45 +bool nand_page_is_empty(struct mtd_info *mtd, void *data, void *oob)
  46 +{
  47 +       u8 *buf;
  48 +       int length;
  49 +       u32 pattern = 0xffffffff;
  50 +       int bitflips = 0;
  51 +       int cnt;
  52 +
  53 +       buf = data;
  54 +       length = mtd->writesize;
  55 +       while (length) {
  56 +               cnt = length < sizeof(pattern) ? length : sizeof(pattern);
  57 +               if (memcmp(&pattern, buf, cnt)) {
  58 +                       int i;
  59 +                       for (i = 0; i < cnt * BITS_PER_BYTE; i++) {
  60 +                               if (!(buf[i / BITS_PER_BYTE] &
  61 +                                     (1 << (i % BITS_PER_BYTE)))) {
  62 +                                       bitflips++;
  63 +                                       if (bitflips > mtd->ecc_strength)
  64 +                                               return false;
  65 +                               }
  66 +                       }
  67 +               }
  68 +
  69 +               buf += sizeof(pattern);
  70 +               length -= sizeof(pattern);
  71 +       }
  72 +
  73 +       buf = oob;
  74 +       length = mtd->oobsize;
  75 +       while (length) {
  76 +               cnt = length < sizeof(pattern) ? length : sizeof(pattern);
  77 +               if (memcmp(&pattern, buf, cnt)) {
  78 +                       int i;
  79 +                       for (i = 0; i < cnt * BITS_PER_BYTE; i++) {
  80 +                               if (!(buf[i / BITS_PER_BYTE] &
  81 +                                     (1 << (i % BITS_PER_BYTE)))) {
  82 +                                       bitflips++;
  83 +                                       if (bitflips > mtd->ecc_strength)
  84 +                                               return false;
  85 +                               }
  86 +                       }
  87 +               }
  88 +
  89 +               buf += sizeof(pattern);
  90 +               length -= sizeof(pattern);
  91 +       }
  92 +
  93 +       return true;
  94 +}
  95 +EXPORT_SYMBOL(nand_page_is_empty);
  96 +
  97 +/**
  98 + * nand_page_get_status - retrieve page status from the page status table (pst)
  99 + * @mtd:       mtd info
 100 + * @page:      page you want to get status on
 101 + *
 102 + * Return the page status.
 103 + */
 104 +int nand_page_get_status(struct mtd_info *mtd, int page)
 105 +{
 106 +       struct nand_chip *chip = mtd->priv;
 107 +       u8 shift = (page % 4) * 2;
 108 +       uint64_t offset = page / 4;
 109 +       int ret = NAND_PAGE_STATUS_UNKNOWN;
 110 +
 111 +       if (chip->pst)
 112 +               ret = (chip->pst[offset] >> shift) & 0x3;
 113 +
 114 +       return ret;
 115 +}
 116 +EXPORT_SYMBOL(nand_page_get_status);
 117 +
 118 +/**
 119 + * nand_page_set_status - assign page status from in the page status table
 120 + * @mtd:       mtd info
 121 + * @page:      page you want to get status on
 122 + * @status:    new status to assign
 123 + */
 124 +void nand_page_set_status(struct mtd_info *mtd, int page,
 125 +                         enum nand_page_status status)
 126 +{
 127 +       struct nand_chip *chip = mtd->priv;
 128 +       u8 shift;
 129 +       uint64_t offset;
 130 +
 131 +       if (!chip->pst)
 132 +               return;
 133 +
 134 +       shift = (page % 4) * 2;
 135 +       offset = page / 4;
 136 +       chip->pst[offset] &= ~(0x3 << shift);
 137 +       chip->pst[offset] |= (status & 0x3) << shift;
 138 +}
 139 +EXPORT_SYMBOL(nand_page_set_status);
 140 +
 141 +/**
 142 + * nand_pst_create - create a page status table
 143 + * @mtd:       mtd info
 144 + *
 145 + * Allocate a page status table and assign it to the mtd device.
 146 + *
 147 + * Returns 0 in case of success or -ERRNO in case of error.
 148 + */
 149 +int nand_pst_create(struct mtd_info *mtd)
 150 +{
 151 +       struct nand_chip *chip = mtd->priv;
 152 +
 153 +       if (chip->pst)
 154 +               return 0;
 155 +
 156 +       chip->pst = kzalloc(mtd->size >>
 157 +                           (chip->page_shift + mtd->subpage_sft + 2),
 158 +                           GFP_KERNEL);
 159 +       if (!chip->pst)
 160 +               return -ENOMEM;
 161 +
 162 +       return 0;
 163 +}
 164 +EXPORT_SYMBOL(nand_pst_create);
 165 +
 166 +/**
 167   * nand_read_page_raw - [INTERN] read raw page data without ecc
 168   * @mtd: mtd info structure
 169   * @chip: nand chip info structure
 170 @@ -2539,6 +2671,7 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to,
 171                 uint8_t *wbuf = buf;
 172                 int use_bufpoi;
 173                 int part_pagewr = (column || writelen < (mtd->writesize - 1));
 174 +               int subpage;
 175
 176                 if (part_pagewr)
 177                         use_bufpoi = 1;
 178 @@ -2574,6 +2707,14 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to,
 179                 if (ret)
 180                         break;
 181
 182 +               for (subpage = column / chip->subpagesize;
 183 +                    subpage < (column + writelen) / chip->subpagesize;
 184 +                    subpage++)
 185 +                       nand_page_set_status(mtd,
 186 +                                            (page << mtd->subpage_sft) +
 187 +                                            subpage,
 188 +                                            NAND_PAGE_FILLED);
 189 +
 190                 writelen -= bytes;
 191                 if (!writelen)
 192                         break;
 193 @@ -2979,6 +3120,7 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
 194         int page, status, pages_per_block, ret, chipnr;
 195         struct nand_chip *chip = mtd->priv;
 196         loff_t len;
 197 +       int i;
 198
 199         pr_debug("%s: start = 0x%012llx, len = %llu\n",
 200                         __func__, (unsigned long long)instr->addr,
 201 @@ -3051,6 +3193,18 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
 202                         goto erase_exit;
 203                 }
 204
 205 +               for (i = 0; i < pages_per_block; i++) {
 206 +                       int subpage;
 207 +                       for (subpage = 0;
 208 +                            subpage < 1 << mtd->subpage_sft;
 209 +                            subpage++) {
 210 +                               nand_page_set_status(mtd,
 211 +                                       ((page + i) << mtd->subpage_sft) +
 212 +                                       subpage,
 213 +                                       NAND_PAGE_EMPTY);
 214 +                       }
 215 +               }
 216 +
 217                 /* Increment page address and decrement length */
 218                 len -= (1ULL << chip->phys_erase_shift);
 219                 page += pages_per_block;
 220 diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
 221 index 5616f51..4f7ca8d 100644
 222 --- a/include/linux/mtd/nand.h
 223 +++ b/include/linux/mtd/nand.h
 224 @@ -521,6 +521,24 @@ struct nand_ecc_ctrl {
 225                         int page);
 226  };
 227
 228 +/*
 229 + * Constants for page status
 230 + */
 231 +enum nand_page_status {
 232 +       NAND_PAGE_STATUS_UNKNOWN,
 233 +       NAND_PAGE_EMPTY,
 234 +       NAND_PAGE_FILLED,
 235 +};
 236 +
 237 +bool nand_page_is_empty(struct mtd_info *mtd, void *data, void *oob);
 238 +
 239 +int nand_page_get_status(struct mtd_info *mtd, int page);
 240 +
 241 +void nand_page_set_status(struct mtd_info *mtd, int page,
 242 +                         enum nand_page_status status);
 243 +
 244 +int nand_pst_create(struct mtd_info *mtd);
 245 +
 246  /**
 247   * struct nand_buffers - buffer structure for read/write
 248   * @ecccalc:   buffer pointer for calculated ECC, size is oobsize.
 249 @@ -630,6 +648,7 @@ struct nand_buffers {
 250   * @bbt_md:            [REPLACEABLE] bad block table mirror descriptor
 251   * @badblock_pattern:  [REPLACEABLE] bad block scan pattern used for initial
 252   *                     bad block scan.
 253 + * @pst:               [INTERN] page status table
 254   * @controller:                [REPLACEABLE] a pointer to a hardware controller
 255   *                     structure which is shared among multiple independent
 256   *                     devices.
 257 @@ -718,6 +737,8 @@ struct nand_chip {
 258
 259         struct nand_bbt_descr *badblock_pattern;
 260
 261 +       uint8_t *pst;
 262 +
 263         struct list_head partitions;
 264         struct mutex part_lock;
 265