target/linux/brcm47xx/patches-3.18/030-06-MIPS-BCM47XX-Use-mtd-as-an-alternative-way-API-to-ge.patch

   1 From 9d1d08646af4491aec41d40341930b9bfd62ffa9 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
   3 Date: Wed, 29 Oct 2014 10:05:06 +0100
   4 Subject: [PATCH] MIPS: BCM47XX: Use mtd as an alternative way/API to get NVRAM
   5  content
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   9
  10 NVRAM can be read using magic memory offset, but after all it's just a
  11 flash partition. On platforms where NVRAM isn't needed early we can get
  12 it using mtd subsystem.
  13
  14 Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
  15 Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
  16 Cc: linux-mips@linux-mips.org
  17 Patchwork: https://patchwork.linux-mips.org/patch/8266/
  18 Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
  19 ---
  20  arch/mips/bcm47xx/nvram.c | 42 ++++++++++++++++++++++++++++++++++++++----
  21  1 file changed, 38 insertions(+), 4 deletions(-)
  22
  23 --- a/arch/mips/bcm47xx/nvram.c
  24 +++ b/arch/mips/bcm47xx/nvram.c
  25 @@ -13,12 +13,10 @@
  26
  27  #include <linux/types.h>
  28  #include <linux/module.h>
  29 -#include <linux/ssb/ssb.h>
  30  #include <linux/kernel.h>
  31  #include <linux/string.h>
  32 -#include <asm/addrspace.h>
  33 +#include <linux/mtd/mtd.h>
  34  #include <bcm47xx_nvram.h>
  35 -#include <asm/mach-bcm47xx/bcm47xx.h>
  36
  37  static char nvram_buf[NVRAM_SPACE];
  38  static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
  39 @@ -123,7 +121,43 @@ int bcm47xx_nvram_init_from_mem(u32 base
  40
  41  static int nvram_init(void)
  42  {
  43 -       /* TODO: Look for MTD "nvram" partition */
  44 +#ifdef CONFIG_MTD
  45 +       struct mtd_info *mtd;
  46 +       struct nvram_header header;
  47 +       size_t bytes_read;
  48 +       int err, i;
  49 +
  50 +       mtd = get_mtd_device_nm("nvram");
  51 +       if (IS_ERR(mtd))
  52 +               return -ENODEV;
  53 +
  54 +       for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
  55 +               loff_t from = mtd->size - nvram_sizes[i];
  56 +
  57 +               if (from < 0)
  58 +                       continue;
  59 +
  60 +               err = mtd_read(mtd, from, sizeof(header), &bytes_read,
  61 +                              (uint8_t *)&header);
  62 +               if (!err && header.magic == NVRAM_HEADER) {
  63 +                       u8 *dst = (uint8_t *)nvram_buf;
  64 +                       size_t len = header.len;
  65 +
  66 +                       if (header.len > NVRAM_SPACE) {
  67 +                               pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
  68 +                                      header.len, NVRAM_SPACE);
  69 +                               len = NVRAM_SPACE;
  70 +                       }
  71 +
  72 +                       err = mtd_read(mtd, from, len, &bytes_read, dst);
  73 +                       if (err)
  74 +                               return err;
  75 +                       memset(dst + bytes_read, 0x0, NVRAM_SPACE - bytes_read);
  76 +
  77 +                       return 0;
  78 +               }
  79 +       }
  80 +#endif
  81
  82         return -ENXIO;
  83  }