target/linux/generic/backport-5.10/800-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 diff --git a/drivers/firmware/broadcom/bcm47xx_nvram.c b/drivers/firmware/broadcom/bcm47xx_nvram.c
  18 index b04007adc79f..99f3ec180be6 100644
  19 --- a/drivers/firmware/broadcom/bcm47xx_nvram.c
  20 +++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
  21 @@ -34,14 +34,20 @@ static char nvram_buf[NVRAM_SPACE];
  22  static size_t nvram_len;
  23  static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000};
  24
  25 +/**
  26 + * bcm47xx_nvram_is_valid - check for a valid NVRAM at specified memory
  27 + */
  28 +static bool bcm47xx_nvram_is_valid(void __iomem *nvram)
  29 +{
  30 +       return ((struct nvram_header *)nvram)->magic == NVRAM_MAGIC;
  31 +}
  32 +
  33  static u32 find_nvram_size(void __iomem *end)
  34  {
  35 -       struct nvram_header __iomem *header;
  36         int i;
  37
  38         for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
  39 -               header = (struct nvram_header *)(end - nvram_sizes[i]);
  40 -               if (header->magic == NVRAM_MAGIC)
  41 +               if (bcm47xx_nvram_is_valid(end - nvram_sizes[i]))
  42                         return nvram_sizes[i];
  43         }
  44
  45 @@ -55,6 +61,7 @@ static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_siz
  46  {
  47         struct nvram_header __iomem *header;
  48         size_t flash_size;
  49 +       size_t offset;
  50         u32 size;
  51
  52         if (nvram_len) {
  53 @@ -68,31 +75,30 @@ static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_siz
  54                 /* Windowed flash access */
  55                 size = find_nvram_size(flash_start + flash_size);
  56                 if (size) {
  57 -                       header = (struct nvram_header *)(flash_start + flash_size - size);
  58 +                       offset = flash_size - size;
  59                         goto found;
  60                 }
  61                 flash_size <<= 1;
  62         }
  63
  64         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
  65 -       header = (struct nvram_header *)(flash_start + 4096);
  66 -       if (header->magic == NVRAM_MAGIC) {
  67 -               size = NVRAM_SPACE;
  68 +
  69 +       offset = 4096;
  70 +       if (bcm47xx_nvram_is_valid(flash_start + offset))
  71                 goto found;
  72 -       }
  73
  74 -       header = (struct nvram_header *)(flash_start + 1024);
  75 -       if (header->magic == NVRAM_MAGIC) {
  76 -               size = NVRAM_SPACE;
  77 +       offset = 1024;
  78 +       if (bcm47xx_nvram_is_valid(flash_start + offset))
  79                 goto found;
  80 -       }
  81
  82         pr_err("no nvram found\n");
  83         return -ENXIO;
  84
  85  found:
  86 +       header = (struct nvram_header *)(flash_start + offset);
  87         __ioread32_copy(nvram_buf, header, sizeof(*header) / 4);
  88         nvram_len = ((struct nvram_header *)(nvram_buf))->len;
  89 +       size = res_size - offset;
  90         if (nvram_len > size) {
  91                 pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n");
  92                 nvram_len = size;
  93 --
  94 2.26.2
  95