target/linux/ramips/patches-4.9/0053-mtd-spi-nor-add-w25q256-3b-mode-switch.patch

   1 mtd: spi-nor: add support for switching between 3-byte and 4-byte addressing on w25q256 flash
   2
   3 On some devices the flash chip needs to be in 3-byte addressing mode during
   4 reboot, otherwise the boot loader will fail to start.
   5 This mode however does not allow regular reads/writes onto the upper 16M
   6 half. W25Q256 has separate read commands for reading from >16M, however
   7 it does not have any separate write commands.
   8 This patch changes the code to leave the chip in 3-byte mode most of the
   9 time and only switch during erase/write cycles that go to >16M
  10 addresses.
  11
  12 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  13 ---
  14 --- a/drivers/mtd/spi-nor/spi-nor.c
  15 +++ b/drivers/mtd/spi-nor/spi-nor.c
  16 @@ -85,6 +85,10 @@ struct flash_info {
  17                                          * Use dedicated 4byte address op codes
  18                                          * to support memory size above 128Mib.
  19                                          */
  20 +#define SPI_NOR_4B_READ_OP     BIT(12) /*
  21 +                                        * Like SPI_NOR_4B_OPCODES, but for read
  22 +                                        * op code only.
  23 +                                        */
  24  };
  25
  26  #define JEDEC_MFR(info)        ((info)->id[0])
  27 @@ -250,6 +254,15 @@ static inline u8 spi_nor_convert_3to4_er
  28                                       ARRAY_SIZE(spi_nor_3to4_erase));
  29  }
  30
  31 +static void spi_nor_set_4byte_read(struct spi_nor *nor,
  32 +                                  const struct flash_info *info)
  33 +{
  34 +       nor->addr_width = 3;
  35 +       nor->ext_addr = 0;
  36 +       nor->read_opcode = spi_nor_convert_3to4_read(nor->read_opcode);
  37 +       nor->flags |= SNOR_F_4B_EXT_ADDR;
  38 +}
  39 +
  40  static void spi_nor_set_4byte_opcodes(struct spi_nor *nor,
  41                                       const struct flash_info *info)
  42  {
  43 @@ -467,6 +480,36 @@ static int spi_nor_erase_sector(struct s
  44         return nor->write_reg(nor, nor->erase_opcode, buf, nor->addr_width);
  45  }
  46
  47 +static int spi_nor_check_ext_addr(struct spi_nor *nor, u32 addr)
  48 +{
  49 +       bool ext_addr;
  50 +       int ret;
  51 +       u8 cmd;
  52 +
  53 +       if (!(nor->flags & SNOR_F_4B_EXT_ADDR))
  54 +               return 0;
  55 +
  56 +       ext_addr = !!(addr & 0xff000000);
  57 +       if (nor->ext_addr == ext_addr)
  58 +               return 0;
  59 +
  60 +       cmd = ext_addr ? SPINOR_OP_EN4B : SPINOR_OP_EX4B;
  61 +       write_enable(nor);
  62 +       ret = nor->write_reg(nor, cmd, NULL, 0);
  63 +       if (ret)
  64 +               return ret;
  65 +
  66 +       cmd = 0;
  67 +       ret = nor->write_reg(nor, SPINOR_OP_WREAR, &cmd, 1);
  68 +       if (ret)
  69 +               return ret;
  70 +
  71 +       nor->addr_width = 3 + ext_addr;
  72 +       nor->ext_addr = ext_addr;
  73 +       write_disable(nor);
  74 +       return 0;
  75 +}
  76 +
  77  /*
  78   * Erase an address range on the nor chip.  The address range may extend
  79   * one or more erase sectors.  Return an error is there is a problem erasing.
  80 @@ -492,6 +535,10 @@ static int spi_nor_erase(struct mtd_info
  81         if (ret)
  82                 return ret;
  83
  84 +       ret = spi_nor_check_ext_addr(nor, addr + len);
  85 +       if (ret)
  86 +               return ret;
  87 +
  88         /* whole-chip erase? */
  89         if (len == mtd->size && !(nor->flags & SNOR_F_NO_OP_CHIP_ERASE)) {
  90                 unsigned long timeout;
  91 @@ -542,6 +589,7 @@ static int spi_nor_erase(struct mtd_info
  92         write_disable(nor);
  93
  94  erase_err:
  95 +       spi_nor_check_ext_addr(nor, 0);
  96         spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_ERASE);
  97
  98         instr->state = ret ? MTD_ERASE_FAILED : MTD_ERASE_DONE;
  99 @@ -834,7 +882,9 @@ static int spi_nor_lock(struct mtd_info
 100         if (ret)
 101                 return ret;
 102
 103 +       spi_nor_check_ext_addr(nor, ofs + len);
 104         ret = nor->flash_lock(nor, ofs, len);
 105 +       spi_nor_check_ext_addr(nor, 0);
 106
 107         spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_UNLOCK);
 108         return ret;
 109 @@ -849,7 +899,9 @@ static int spi_nor_unlock(struct mtd_inf
 110         if (ret)
 111                 return ret;
 112
 113 +       spi_nor_check_ext_addr(nor, ofs + len);
 114         ret = nor->flash_unlock(nor, ofs, len);
 115 +       spi_nor_check_ext_addr(nor, 0);
 116
 117         spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
 118         return ret;
 119 @@ -1151,7 +1203,7 @@ static const struct flash_info spi_nor_i
 120         { "w25q80", INFO(0xef5014, 0, 64 * 1024,  16, SECT_4K) },
 121         { "w25q80bl", INFO(0xef4014, 0, 64 * 1024,  16, SECT_4K) },
 122         { "w25q128", INFO(0xef4018, 0, 64 * 1024, 256, SECT_4K) },
 123 -       { "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K) },
 124 +       { "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_4B_READ_OP) },
 125
 126         /* Catalyst / On Semiconductor -- non-JEDEC */
 127         { "cat25c11", CAT25_INFO(  16, 8, 16, 1, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
 128 @@ -1205,6 +1257,9 @@ static int spi_nor_read(struct mtd_info
 129         if (ret)
 130                 return ret;
 131
 132 +       if (nor->flags & SNOR_F_4B_EXT_ADDR)
 133 +               nor->addr_width = 4;
 134 +
 135         while (len) {
 136                 loff_t addr = from;
 137
 138 @@ -1229,6 +1284,18 @@ static int spi_nor_read(struct mtd_info
 139         ret = 0;
 140
 141  read_err:
 142 +       if (nor->flags & SNOR_F_4B_EXT_ADDR) {
 143 +               u8 val = 0;
 144 +
 145 +               if ((from + len) & 0xff000000) {
 146 +                       write_enable(nor);
 147 +                       nor->write_reg(nor, SPINOR_OP_WREAR, &val, 1);
 148 +                       write_disable(nor);
 149 +               }
 150 +
 151 +               nor->addr_width = 3;
 152 +       }
 153 +
 154         spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
 155         return ret;
 156  }
 157 @@ -1330,6 +1397,10 @@ static int spi_nor_write(struct mtd_info
 158         if (ret)
 159                 return ret;
 160
 161 +       ret = spi_nor_check_ext_addr(nor, to + len);
 162 +       if (ret < 0)
 163 +               return ret;
 164 +
 165         for (i = 0; i < len; ) {
 166                 ssize_t written;
 167                 loff_t addr = to + i;
 168 @@ -1377,6 +1448,7 @@ static int spi_nor_write(struct mtd_info
 169         }
 170
 171  write_err:
 172 +       spi_nor_check_ext_addr(nor, 0);
 173         spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
 174         return ret;
 175  }
 176 @@ -1717,8 +1789,10 @@ int spi_nor_scan(struct spi_nor *nor, co
 177         else if (mtd->size > 0x1000000) {
 178                 /* enable 4-byte addressing if the device exceeds 16MiB */
 179                 nor->addr_width = 4;
 180 -               if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
 181 -                   info->flags & SPI_NOR_4B_OPCODES)
 182 +               if (info->flags & SPI_NOR_4B_READ_OP)
 183 +                       spi_nor_set_4byte_read(nor, info);
 184 +               else if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
 185 +                        info->flags & SPI_NOR_4B_OPCODES)
 186                         spi_nor_set_4byte_opcodes(nor, info);
 187                 else
 188                         set_4byte(nor, info, 1);
 189 --- a/include/linux/mtd/spi-nor.h
 190 +++ b/include/linux/mtd/spi-nor.h
 191 @@ -90,6 +90,7 @@
 192  /* Used for Macronix and Winbond flashes. */
 193  #define SPINOR_OP_EN4B         0xb7    /* Enter 4-byte mode */
 194  #define SPINOR_OP_EX4B         0xe9    /* Exit 4-byte mode */
 195 +#define SPINOR_OP_WREAR                0xc5    /* Write extended address register */
 196
 197  /* Used for Spansion flashes only. */
 198  #define SPINOR_OP_BRWR         0x17    /* Bank register write */
 199 @@ -141,6 +142,7 @@ enum spi_nor_option_flags {
 200         SNOR_F_NO_OP_CHIP_ERASE = BIT(2),
 201         SNOR_F_S3AN_ADDR_DEFAULT = BIT(3),
 202         SNOR_F_READY_XSR_RDY    = BIT(4),
 203 +       SNOR_F_4B_EXT_ADDR      = BIT(5),
 204  };
 205
 206  /**
 207 @@ -188,6 +190,7 @@ struct spi_nor {
 208         enum read_mode          flash_read;
 209         bool                    sst_write_second;
 210         u32                     flags;
 211 +       u8                      ext_addr;
 212         u8                      cmd_buf[SPI_NOR_MAX_CMD_SIZE];
 213
 214         int (*prepare)(struct spi_nor *nor, enum spi_nor_ops ops);