target/linux/oxnas/patches-4.4/0073-of-mtd-prepare-helper-reading-NAND-ECC-algo-from-DT.patch

   1 From 410a91f6efa1c4c3c4369d1dd2c31286749dff33 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
   3 Date: Wed, 23 Mar 2016 11:19:01 +0100
   4 Subject: [PATCH 073/102] of: mtd: prepare helper reading NAND ECC algo from
   5  DT
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 NAND subsystem is being slightly reworked to store ECC details in
  11 separated fields. In future we'll want to add support for more DT
  12 properties as specifying every possible setup with a single
  13 "nand-ecc-mode" is a pretty bad idea.
  14 To allow this let's add a helper that will support something like
  15 "nand-ecc-algo" in future. Right now we use it for keeping backward
  16 compatibility.
  17
  18 Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
  19 Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
  20 ---
  21  drivers/of/of_mtd.c    |   36 ++++++++++++++++++++++++++++++++++++
  22  include/linux/of_mtd.h |    6 ++++++
  23  2 files changed, 42 insertions(+)
  24
  25 --- a/drivers/of/of_mtd.c
  26 +++ b/drivers/of/of_mtd.c
  27 @@ -50,6 +50,42 @@ int of_get_nand_ecc_mode(struct device_n
  28  EXPORT_SYMBOL_GPL(of_get_nand_ecc_mode);
  29
  30  /**
  31 + * of_get_nand_ecc_algo - Get nand ecc algorithm for given device_node
  32 + * @np:        Pointer to the given device_node
  33 + *
  34 + * The function gets ecc algorithm and returns its enum value, or errno in error
  35 + * case.
  36 + */
  37 +int of_get_nand_ecc_algo(struct device_node *np)
  38 +{
  39 +       const char *pm;
  40 +       int err;
  41 +
  42 +       /*
  43 +        * TODO: Read ECC algo OF property and map it to enum nand_ecc_algo.
  44 +        * It's not implemented yet as currently NAND subsystem ignores
  45 +        * algorithm explicitly set this way. Once it's handled we should
  46 +        * document & support new property.
  47 +        */
  48 +
  49 +       /*
  50 +        * For backward compatibility we also read "nand-ecc-mode" checking
  51 +        * for some obsoleted values that were specifying ECC algorithm.
  52 +        */
  53 +       err = of_property_read_string(np, "nand-ecc-mode", &pm);
  54 +       if (err < 0)
  55 +               return err;
  56 +
  57 +       if (!strcasecmp(pm, "soft"))
  58 +               return NAND_ECC_HAMMING;
  59 +       else if (!strcasecmp(pm, "soft_bch"))
  60 +               return NAND_ECC_BCH;
  61 +
  62 +       return -ENODEV;
  63 +}
  64 +EXPORT_SYMBOL_GPL(of_get_nand_ecc_algo);
  65 +
  66 +/**
  67   * of_get_nand_ecc_step_size - Get ECC step size associated to
  68   * the required ECC strength (see below).
  69   * @np:        Pointer to the given device_node
  70 --- a/include/linux/of_mtd.h
  71 +++ b/include/linux/of_mtd.h
  72 @@ -13,6 +13,7 @@
  73
  74  #include <linux/of.h>
  75  int of_get_nand_ecc_mode(struct device_node *np);
  76 +int of_get_nand_ecc_algo(struct device_node *np);
  77  int of_get_nand_ecc_step_size(struct device_node *np);
  78  int of_get_nand_ecc_strength(struct device_node *np);
  79  int of_get_nand_bus_width(struct device_node *np);
  80 @@ -24,6 +25,11 @@ static inline int of_get_nand_ecc_mode(s
  81  {
  82         return -ENOSYS;
  83  }
  84 +
  85 +static inline int of_get_nand_ecc_algo(struct device_node *np)
  86 +{
  87 +       return -ENOSYS;
  88 +}
  89
  90  static inline int of_get_nand_ecc_step_size(struct device_node *np)
  91  {