target/linux/generic/backport-6.1/410-v6.2-mtd-spi-nor-add-generic-flash-driver.patch

   1 From 773bbe10449731c9525457873e0c2342e5cf883b Mon Sep 17 00:00:00 2001
   2 From: Michael Walle <michael@walle.cc>
   3 Date: Thu, 11 Aug 2022 00:06:53 +0200
   4 Subject: [PATCH] mtd: spi-nor: add generic flash driver
   5
   6 Our SFDP parsing is everything we need to support all basic operations
   7 of a flash device. If the flash isn't found in our in-kernel flash
   8 database, gracefully fall back to a driver described solely by its SFDP
   9 tables.
  10
  11 Signed-off-by: Michael Walle <michael@walle.cc>
  12 Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
  13 Tested-by: Tudor Ambarus <tudor.ambarus@microchip.com>
  14 Reviewed-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
  15 Link: https://lore.kernel.org/r/20220810220654.1297699-7-michael@walle.cc
  16 ---
  17  drivers/mtd/spi-nor/core.c | 26 ++++++++++++++++++++++++--
  18  drivers/mtd/spi-nor/core.h |  1 +
  19  drivers/mtd/spi-nor/sfdp.c | 27 +++++++++++++++++++++++++++
  20  3 files changed, 52 insertions(+), 2 deletions(-)
  21
  22 --- a/drivers/mtd/spi-nor/core.c
  23 +++ b/drivers/mtd/spi-nor/core.c
  24 @@ -1636,6 +1636,16 @@ static const struct spi_nor_manufacturer
  25         &spi_nor_xmc,
  26  };
  27
  28 +static const struct flash_info spi_nor_generic_flash = {
  29 +       .name = "spi-nor-generic",
  30 +       /*
  31 +        * JESD216 rev A doesn't specify the page size, therefore we need a
  32 +        * sane default.
  33 +        */
  34 +       .page_size = 256,
  35 +       .parse_sfdp = true,
  36 +};
  37 +
  38  static const struct flash_info *spi_nor_match_id(struct spi_nor *nor,
  39                                                  const u8 *id)
  40  {
  41 @@ -1669,6 +1679,14 @@ static const struct flash_info *spi_nor_
  42         }
  43
  44         info = spi_nor_match_id(nor, id);
  45 +
  46 +       /* Fallback to a generic flash described only by its SFDP data. */
  47 +       if (!info) {
  48 +               ret = spi_nor_check_sfdp_signature(nor);
  49 +               if (!ret)
  50 +                       info = &spi_nor_generic_flash;
  51 +       }
  52 +
  53         if (!info) {
  54                 dev_err(nor->dev, "unrecognized JEDEC id bytes: %*ph\n",
  55                         SPI_NOR_MAX_ID_LEN, id);
  56 @@ -2105,8 +2123,12 @@ static int spi_nor_select_pp(struct spi_
  57   * spi_nor_select_uniform_erase() - select optimum uniform erase type
  58   * @map:               the erase map of the SPI NOR
  59   * @wanted_size:       the erase type size to search for. Contains the value of
  60 - *                     info->sector_size or of the "small sector" size in case
  61 - *                     CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined.
  62 + *                     info->sector_size, the "small sector" size in case
  63 + *                     CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined or 0 if
  64 + *                     there is no information about the sector size. The
  65 + *                     latter is the case if the flash parameters are parsed
  66 + *                     solely by SFDP, then the largest supported erase type
  67 + *                     is selected.
  68   *
  69   * Once the optimum uniform sector erase command is found, disable all the
  70   * other.
  71 --- a/drivers/mtd/spi-nor/core.h
  72 +++ b/drivers/mtd/spi-nor/core.h
  73 @@ -708,6 +708,8 @@ int spi_nor_controller_ops_read_reg(stru
  74  int spi_nor_controller_ops_write_reg(struct spi_nor *nor, u8 opcode,
  75                                      const u8 *buf, size_t len);
  76
  77 +int spi_nor_check_sfdp_signature(struct spi_nor *nor);
  78 +
  79  static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
  80  {
  81         return container_of(mtd, struct spi_nor, mtd);
  82 --- a/drivers/mtd/spi-nor/sfdp.c
  83 +++ b/drivers/mtd/spi-nor/sfdp.c
  84 @@ -1250,6 +1250,33 @@ static void spi_nor_post_sfdp_fixups(str
  85  }
  86
  87  /**
  88 + * spi_nor_check_sfdp_signature() - check for a valid SFDP signature
  89 + * @nor:       pointer to a 'struct spi_nor'
  90 + *
  91 + * Used to detect if the flash supports the RDSFDP command as well as the
  92 + * presence of a valid SFDP table.
  93 + *
  94 + * Return: 0 on success, -errno otherwise.
  95 + */
  96 +int spi_nor_check_sfdp_signature(struct spi_nor *nor)
  97 +{
  98 +       u32 signature;
  99 +       int err;
 100 +
 101 +       /* Get the SFDP header. */
 102 +       err = spi_nor_read_sfdp_dma_unsafe(nor, 0, sizeof(signature),
 103 +                                          &signature);
 104 +       if (err < 0)
 105 +               return err;
 106 +
 107 +       /* Check the SFDP signature. */
 108 +       if (le32_to_cpu(signature) != SFDP_SIGNATURE)
 109 +               return -EINVAL;
 110 +
 111 +       return 0;
 112 +}
 113 +
 114 +/**
 115   * spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters.
 116   * @nor:               pointer to a 'struct spi_nor'
 117   *