target/linux/generic/backport-5.4/831-v5.13-0002-firmware-bcm47xx_nvram-add-helper-checking-for-NVRAM.patch

   1 From 0a24b51a3264a3f942a75025ea5ff6133c8989b0 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   3 Date: Mon, 8 Mar 2021 10:03:17 +0100
   4 Subject: [PATCH] firmware: bcm47xx_nvram: add helper checking for NVRAM
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 This avoids duplicating code doing casting and checking for NVRAM magic.
  10
  11 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  12 Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
  13 ---
  14  drivers/firmware/broadcom/bcm47xx_nvram.c | 30 ++++++++++++++---------
  15  1 file changed, 18 insertions(+), 12 deletions(-)
  16
  17 --- a/drivers/firmware/broadcom/bcm47xx_nvram.c
  18 +++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
  19 @@ -34,14 +34,20 @@ static char nvram_buf[NVRAM_SPACE];
  20  static size_t nvram_len;
  21  static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000};
  22
  23 +/**
  24 + * bcm47xx_nvram_is_valid - check for a valid NVRAM at specified memory
  25 + */
  26 +static bool bcm47xx_nvram_is_valid(void __iomem *nvram)
  27 +{
  28 +       return ((struct nvram_header *)nvram)->magic == NVRAM_MAGIC;
  29 +}
  30 +
  31  static u32 find_nvram_size(void __iomem *end)
  32  {
  33 -       struct nvram_header __iomem *header;
  34         int i;
  35
  36         for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
  37 -               header = (struct nvram_header *)(end - nvram_sizes[i]);
  38 -               if (header->magic == NVRAM_MAGIC)
  39 +               if (bcm47xx_nvram_is_valid(end - nvram_sizes[i]))
  40                         return nvram_sizes[i];
  41         }
  42
  43 @@ -55,6 +61,7 @@ static int bcm47xx_nvram_find_and_copy(v
  44  {
  45         struct nvram_header __iomem *header;
  46         size_t flash_size;
  47 +       size_t offset;
  48         u32 size;
  49
  50         if (nvram_len) {
  51 @@ -68,31 +75,30 @@ static int bcm47xx_nvram_find_and_copy(v
  52                 /* Windowed flash access */
  53                 size = find_nvram_size(flash_start + flash_size);
  54                 if (size) {
  55 -                       header = (struct nvram_header *)(flash_start + flash_size - size);
  56 +                       offset = flash_size - size;
  57                         goto found;
  58                 }
  59                 flash_size <<= 1;
  60         }
  61
  62         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
  63 -       header = (struct nvram_header *)(flash_start + 4096);
  64 -       if (header->magic == NVRAM_MAGIC) {
  65 -               size = NVRAM_SPACE;
  66 +
  67 +       offset = 4096;
  68 +       if (bcm47xx_nvram_is_valid(flash_start + offset))
  69                 goto found;
  70 -       }
  71
  72 -       header = (struct nvram_header *)(flash_start + 1024);
  73 -       if (header->magic == NVRAM_MAGIC) {
  74 -               size = NVRAM_SPACE;
  75 +       offset = 1024;
  76 +       if (bcm47xx_nvram_is_valid(flash_start + offset))
  77                 goto found;
  78 -       }
  79
  80         pr_err("no nvram found\n");
  81         return -ENXIO;
  82
  83  found:
  84 +       header = (struct nvram_header *)(flash_start + offset);
  85         __ioread32_copy(nvram_buf, header, sizeof(*header) / 4);
  86         nvram_len = ((struct nvram_header *)(nvram_buf))->len;
  87 +       size = res_size - offset;
  88         if (nvram_len > size) {
  89                 pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n");
  90                 nvram_len = size;