target/linux/generic/backport-5.15/820-v6.7-0006-nvmem-brcm_nvram-store-a-copy-of-NVRAM-content.patch

   1 From 1e37bf84afacd5ba17b7a13a18ca2bc78aff05c0 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   3 Date: Fri, 15 Dec 2023 11:13:58 +0000
   4 Subject: [PATCH] nvmem: brcm_nvram: store a copy of NVRAM content
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 This driver uses MMIO access for reading NVRAM from a flash device.
  10 Underneath there is a flash controller that reads data and provides
  11 mapping window.
  12
  13 Using MMIO interface affects controller configuration and may break real
  14 controller driver. It was reported by multiple users of devices with
  15 NVRAM stored on NAND.
  16
  17 Modify driver to read & cache NVRAM content during init and use that
  18 copy to provide NVMEM data when requested. On NAND flashes due to their
  19 alignment NVRAM partitions can be quite big (1 MiB and more) while
  20 actual NVRAM content stays quite small (usually 16 to 32 KiB). To avoid
  21 allocating so much memory check for actual data length.
  22
  23 Link: https://lore.kernel.org/linux-mtd/CACna6rwf3_9QVjYcM+847biTX=K0EoWXuXcSMkJO1Vy_5vmVqA@mail.gmail.com/
  24 Fixes: 3fef9ed0627a ("nvmem: brcm_nvram: new driver exposing Broadcom's NVRAM")
  25 Cc:  <Stable@vger.kernel.org>
  26 Cc: Arınç ÜNAL <arinc.unal@arinc9.com>
  27 Cc: Florian Fainelli <florian.fainelli@broadcom.com>
  28 Cc: Scott Branden <scott.branden@broadcom.com>
  29 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  30 Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
  31 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  32 Link: https://lore.kernel.org/r/20231215111358.316727-3-srinivas.kandagatla@linaro.org
  33 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  34 ---
  35  drivers/nvmem/brcm_nvram.c | 134 ++++++++++++++++++++++++++-----------
  36  1 file changed, 94 insertions(+), 40 deletions(-)
  37
  38 --- a/drivers/nvmem/brcm_nvram.c
  39 +++ b/drivers/nvmem/brcm_nvram.c
  40 @@ -17,9 +17,23 @@
  41
  42  #define NVRAM_MAGIC                    "FLSH"
  43
  44 +/**
  45 + * struct brcm_nvram - driver state internal struct
  46 + *
  47 + * @dev:               NVMEM device pointer
  48 + * @nvmem_size:                Size of the whole space available for NVRAM
  49 + * @data:              NVRAM data copy stored to avoid poking underlaying flash controller
  50 + * @data_len:          NVRAM data size
  51 + * @padding_byte:      Padding value used to fill remaining space
  52 + * @cells:             Array of discovered NVMEM cells
  53 + * @ncells:            Number of elements in cells
  54 + */
  55  struct brcm_nvram {
  56         struct device *dev;
  57 -       void __iomem *base;
  58 +       size_t nvmem_size;
  59 +       uint8_t *data;
  60 +       size_t data_len;
  61 +       uint8_t padding_byte;
  62         struct nvmem_cell_info *cells;
  63         int ncells;
  64  };
  65 @@ -36,10 +50,47 @@ static int brcm_nvram_read(void *context
  66                            size_t bytes)
  67  {
  68         struct brcm_nvram *priv = context;
  69 -       u8 *dst = val;
  70 +       size_t to_copy;
  71 +
  72 +       if (offset + bytes > priv->data_len)
  73 +               to_copy = max_t(ssize_t, (ssize_t)priv->data_len - offset, 0);
  74 +       else
  75 +               to_copy = bytes;
  76 +
  77 +       memcpy(val, priv->data + offset, to_copy);
  78 +
  79 +       memset((uint8_t *)val + to_copy, priv->padding_byte, bytes - to_copy);
  80 +
  81 +       return 0;
  82 +}
  83 +
  84 +static int brcm_nvram_copy_data(struct brcm_nvram *priv, struct platform_device *pdev)
  85 +{
  86 +       struct resource *res;
  87 +       void __iomem *base;
  88 +
  89 +       base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
  90 +       if (IS_ERR(base))
  91 +               return PTR_ERR(base);
  92 +
  93 +       priv->nvmem_size = resource_size(res);
  94 +
  95 +       priv->padding_byte = readb(base + priv->nvmem_size - 1);
  96 +       for (priv->data_len = priv->nvmem_size;
  97 +            priv->data_len;
  98 +            priv->data_len--) {
  99 +               if (readb(base + priv->data_len - 1) != priv->padding_byte)
 100 +                       break;
 101 +       }
 102 +       WARN(priv->data_len > SZ_128K, "Unexpected (big) NVRAM size: %zu B\n", priv->data_len);
 103
 104 -       while (bytes--)
 105 -               *dst++ = readb(priv->base + offset++);
 106 +       priv->data = devm_kzalloc(priv->dev, priv->data_len, GFP_KERNEL);
 107 +       if (!priv->data)
 108 +               return -ENOMEM;
 109 +
 110 +       memcpy_fromio(priv->data, base, priv->data_len);
 111 +
 112 +       bcm47xx_nvram_init_from_iomem(base, priv->data_len);
 113
 114         return 0;
 115  }
 116 @@ -67,8 +118,13 @@ static int brcm_nvram_add_cells(struct b
 117                                 size_t len)
 118  {
 119         struct device *dev = priv->dev;
 120 -       char *var, *value, *eq;
 121 +       char *var, *value;
 122 +       uint8_t tmp;
 123         int idx;
 124 +       int err = 0;
 125 +
 126 +       tmp = priv->data[len - 1];
 127 +       priv->data[len - 1] = '\0';
 128
 129         priv->ncells = 0;
 130         for (var = data + sizeof(struct brcm_nvram_header);
 131 @@ -78,67 +134,68 @@ static int brcm_nvram_add_cells(struct b
 132         }
 133
 134         priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
 135 -       if (!priv->cells)
 136 -               return -ENOMEM;
 137 +       if (!priv->cells) {
 138 +               err = -ENOMEM;
 139 +               goto out;
 140 +       }
 141
 142         for (var = data + sizeof(struct brcm_nvram_header), idx = 0;
 143              var < (char *)data + len && *var;
 144              var = value + strlen(value) + 1, idx++) {
 145 +               char *eq, *name;
 146 +
 147                 eq = strchr(var, '=');
 148                 if (!eq)
 149                         break;
 150                 *eq = '\0';
 151 +               name = devm_kstrdup(dev, var, GFP_KERNEL);
 152 +               *eq = '=';
 153 +               if (!name) {
 154 +                       err = -ENOMEM;
 155 +                       goto out;
 156 +               }
 157                 value = eq + 1;
 158
 159 -               priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
 160 -               if (!priv->cells[idx].name)
 161 -                       return -ENOMEM;
 162 +               priv->cells[idx].name = name;
 163                 priv->cells[idx].offset = value - (char *)data;
 164                 priv->cells[idx].bytes = strlen(value);
 165                 priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
 166 -               if (!strcmp(var, "et0macaddr") ||
 167 -                   !strcmp(var, "et1macaddr") ||
 168 -                   !strcmp(var, "et2macaddr")) {
 169 +               if (!strcmp(name, "et0macaddr") ||
 170 +                   !strcmp(name, "et1macaddr") ||
 171 +                   !strcmp(name, "et2macaddr")) {
 172                         priv->cells[idx].raw_len = strlen(value);
 173                         priv->cells[idx].bytes = ETH_ALEN;
 174                         priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr;
 175                 }
 176         }
 177
 178 -       return 0;
 179 +out:
 180 +       priv->data[len - 1] = tmp;
 181 +       return err;
 182  }
 183
 184  static int brcm_nvram_parse(struct brcm_nvram *priv)
 185  {
 186 +       struct brcm_nvram_header *header = (struct brcm_nvram_header *)priv->data;
 187         struct device *dev = priv->dev;
 188 -       struct brcm_nvram_header header;
 189 -       uint8_t *data;
 190         size_t len;
 191         int err;
 192
 193 -       memcpy_fromio(&header, priv->base, sizeof(header));
 194 -
 195 -       if (memcmp(header.magic, NVRAM_MAGIC, 4)) {
 196 +       if (memcmp(header->magic, NVRAM_MAGIC, 4)) {
 197                 dev_err(dev, "Invalid NVRAM magic\n");
 198                 return -EINVAL;
 199         }
 200
 201 -       len = le32_to_cpu(header.len);
 202 -
 203 -       data = kzalloc(len, GFP_KERNEL);
 204 -       if (!data)
 205 -               return -ENOMEM;
 206 -
 207 -       memcpy_fromio(data, priv->base, len);
 208 -       data[len - 1] = '\0';
 209 -
 210 -       err = brcm_nvram_add_cells(priv, data, len);
 211 -       if (err) {
 212 -               dev_err(dev, "Failed to add cells: %d\n", err);
 213 -               return err;
 214 +       len = le32_to_cpu(header->len);
 215 +       if (len > priv->nvmem_size) {
 216 +               dev_err(dev, "NVRAM length (%zd) exceeds mapped size (%zd)\n", len,
 217 +                       priv->nvmem_size);
 218 +               return -EINVAL;
 219         }
 220
 221 -       kfree(data);
 222 +       err = brcm_nvram_add_cells(priv, priv->data, len);
 223 +       if (err)
 224 +               dev_err(dev, "Failed to add cells: %d\n", err);
 225
 226         return 0;
 227  }
 228 @@ -150,7 +207,6 @@ static int brcm_nvram_probe(struct platf
 229                 .reg_read = brcm_nvram_read,
 230         };
 231         struct device *dev = &pdev->dev;
 232 -       struct resource *res;
 233         struct brcm_nvram *priv;
 234         int err;
 235
 236 @@ -159,21 +215,19 @@ static int brcm_nvram_probe(struct platf
 237                 return -ENOMEM;
 238         priv->dev = dev;
 239
 240 -       priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 241 -       if (IS_ERR(priv->base))
 242 -               return PTR_ERR(priv->base);
 243 +       err = brcm_nvram_copy_data(priv, pdev);
 244 +       if (err)
 245 +               return err;
 246
 247         err = brcm_nvram_parse(priv);
 248         if (err)
 249                 return err;
 250
 251 -       bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res));
 252 -
 253         config.dev = dev;
 254         config.cells = priv->cells;
 255         config.ncells = priv->ncells;
 256         config.priv = priv;
 257 -       config.size = resource_size(res);
 258 +       config.size = priv->nvmem_size;
 259
 260         return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
 261  }