drivers/mtd/nand/nand_samsung.c

   1 /*
   2  * Copyright (C) 2017 Free Electrons
   3  * Copyright (C) 2017 NextThing Co
   4  *
   5  * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/mtd/rawnand.h>
  19
  20 static void samsung_nand_decode_id(struct nand_chip *chip)
  21 {
  22         struct mtd_info *mtd = nand_to_mtd(chip);
  23
  24         /* New Samsung (6 byte ID): Samsung K9GAG08U0F (p.44) */
  25         if (chip->id.len == 6 && !nand_is_slc(chip) &&
  26             chip->id.data[5] != 0x00) {
  27                 u8 extid = chip->id.data[3];
  28
  29                 /* Get pagesize */
  30                 mtd->writesize = 2048 << (extid & 0x03);
  31
  32                 extid >>= 2;
  33
  34                 /* Get oobsize */
  35                 switch (((extid >> 2) & 0x4) | (extid & 0x3)) {
  36                 case 1:
  37                         mtd->oobsize = 128;
  38                         break;
  39                 case 2:
  40                         mtd->oobsize = 218;
  41                         break;
  42                 case 3:
  43                         mtd->oobsize = 400;
  44                         break;
  45                 case 4:
  46                         mtd->oobsize = 436;
  47                         break;
  48                 case 5:
  49                         mtd->oobsize = 512;
  50                         break;
  51                 case 6:
  52                         mtd->oobsize = 640;
  53                         break;
  54                 default:
  55                         /*
  56                          * We should never reach this case, but if that
  57                          * happens, this probably means Samsung decided to use
  58                          * a different extended ID format, and we should find
  59                          * a way to support it.
  60                          */
  61                         WARN(1, "Invalid OOB size value");
  62                         break;
  63                 }
  64
  65                 /* Get blocksize */
  66                 extid >>= 2;
  67                 mtd->erasesize = (128 * 1024) <<
  68                                  (((extid >> 1) & 0x04) | (extid & 0x03));
  69
  70                 /* Extract ECC requirements from 5th id byte*/
  71                 extid = (chip->id.data[4] >> 4) & 0x07;
  72                 if (extid < 5) {
  73                         chip->ecc_step_ds = 512;
  74                         chip->ecc_strength_ds = 1 << extid;
  75                 } else {
  76                         chip->ecc_step_ds = 1024;
  77                         switch (extid) {
  78                         case 5:
  79                                 chip->ecc_strength_ds = 24;
  80                                 break;
  81                         case 6:
  82                                 chip->ecc_strength_ds = 40;
  83                                 break;
  84                         case 7:
  85                                 chip->ecc_strength_ds = 60;
  86                                 break;
  87                         default:
  88                                 WARN(1, "Could not decode ECC info");
  89                                 chip->ecc_step_ds = 0;
  90                         }
  91                 }
  92         } else {
  93                 nand_decode_ext_id(chip);
  94         }
  95 }
  96
  97 static int samsung_nand_init(struct nand_chip *chip)
  98 {
  99         struct mtd_info *mtd = nand_to_mtd(chip);
 100
 101         if (mtd->writesize > 512)
 102                 chip->options |= NAND_SAMSUNG_LP_OPTIONS;
 103
 104         if (!nand_is_slc(chip))
 105                 chip->bbt_options |= NAND_BBT_SCANLASTPAGE;
 106         else
 107                 chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
 108
 109         return 0;
 110 }
 111
 112 const struct nand_manufacturer_ops samsung_nand_manuf_ops = {
 113         .detect = samsung_nand_decode_id,
 114         .init = samsung_nand_init,
 115 };