1 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
2 Date: Thu, 14 Sep 2023 07:59:09 +0200
3 Subject: [PATCH] nvmem: brcm_nvram: store a copy of NVRAM content
5 Content-Type: text/plain; charset=UTF-8
6 Content-Transfer-Encoding: 8bit
8 This driver uses MMIO access for reading NVRAM from a flash device.
9 Underneath there is a flash controller that reads data and provides
12 Using MMIO interface affects controller configuration and may break real
13 controller driver. It was reported by multiple users of devices with
16 Modify driver to read & cache NVRAM content during init and use that
17 copy to provide NVMEM data when requested. On NAND flashes due to their
18 alignment NVRAM partitions can be quite big (1 MiB and more) while
19 actual NVRAM content stays quite small (usually 16 to 32 KiB). To avoid
20 allocating so much memory check for actual data length.
22 Link: https://lore.kernel.org/linux-mtd/CACna6rwf3_9QVjYcM+847biTX=K0EoWXuXcSMkJO1Vy_5vmVqA@mail.gmail.com/
23 Fixes: 3fef9ed0627a ("nvmem: brcm_nvram: new driver exposing Broadcom's NVRAM")
24 Cc: Arınç ÜNAL <arinc.unal@arinc9.com>
25 Cc: Florian Fainelli <florian.fainelli@broadcom.com>
26 Cc: Scott Branden <scott.branden@broadcom.com>
27 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
29 drivers/nvmem/brcm_nvram.c | 130 +++++++++++++++++++++++++------------
30 1 file changed, 90 insertions(+), 40 deletions(-)
32 --- a/drivers/nvmem/brcm_nvram.c
33 +++ b/drivers/nvmem/brcm_nvram.c
36 #define NVRAM_MAGIC "FLSH"
39 + * struct brcm_nvram - driver state internal struct
41 + * @nvmem_size: Size of the whole space available for NVRAM
42 + * @data: NVRAM data copy stored to avoid poking underlaying flash controller
43 + * @data_len: NVRAM data size
44 + * @padding_byte: Padding value used to fill remaining space
52 + uint8_t padding_byte;
53 struct nvmem_cell_info *cells;
56 @@ -36,10 +47,47 @@ static int brcm_nvram_read(void *context
59 struct brcm_nvram *priv = context;
63 + if (offset + bytes > priv->data_len)
64 + to_copy = max_t(ssize_t, (ssize_t)priv->data_len - offset, 0);
68 + memcpy(val, priv->data + offset, to_copy);
70 + memset((uint8_t *)val + to_copy, priv->padding_byte, bytes - to_copy);
75 +static int brcm_nvram_copy_data(struct brcm_nvram *priv, struct platform_device *pdev)
77 + struct resource *res;
80 + base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
82 + return PTR_ERR(base);
84 + priv->nvmem_size = resource_size(res);
86 + priv->padding_byte = readb(base + priv->nvmem_size - 1);
87 + for (priv->data_len = priv->nvmem_size;
90 + if (readb(base + priv->data_len - 1) != priv->padding_byte)
93 + WARN(priv->data_len > SZ_128K, "Unexpected (big) NVRAM size: %zu B\n", priv->data_len);
96 - *dst++ = readb(priv->base + offset++);
97 + priv->data = devm_kzalloc(priv->dev, priv->data_len, GFP_KERNEL);
101 + memcpy_fromio(priv->data, base, priv->data_len);
103 + bcm47xx_nvram_init_from_iomem(base, priv->data_len);
107 @@ -67,8 +115,13 @@ static int brcm_nvram_add_cells(struct b
110 struct device *dev = priv->dev;
111 - char *var, *value, *eq;
117 + tmp = priv->data[len - 1];
118 + priv->data[len - 1] = '\0';
121 for (var = data + sizeof(struct brcm_nvram_header);
122 @@ -78,67 +131,67 @@ static int brcm_nvram_add_cells(struct b
125 priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
128 + if (!priv->cells) {
133 for (var = data + sizeof(struct brcm_nvram_header), idx = 0;
134 var < (char *)data + len && *var;
135 var = value + strlen(value) + 1, idx++) {
138 eq = strchr(var, '=');
142 + name = devm_kstrdup(dev, var, GFP_KERNEL);
150 - priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
151 - if (!priv->cells[idx].name)
153 + priv->cells[idx].name = name;
154 priv->cells[idx].offset = value - (char *)data;
155 priv->cells[idx].bytes = strlen(value);
156 priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
157 - if (!strcmp(var, "et0macaddr") ||
158 - !strcmp(var, "et1macaddr") ||
159 - !strcmp(var, "et2macaddr")) {
160 + if (!strcmp(name, "et0macaddr") ||
161 + !strcmp(name, "et1macaddr") ||
162 + !strcmp(name, "et2macaddr")) {
163 priv->cells[idx].raw_len = strlen(value);
164 priv->cells[idx].bytes = ETH_ALEN;
165 priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr;
171 + priv->data[len - 1] = tmp;
175 static int brcm_nvram_parse(struct brcm_nvram *priv)
177 + struct brcm_nvram_header *header = (struct brcm_nvram_header *)priv->data;
178 struct device *dev = priv->dev;
179 - struct brcm_nvram_header header;
184 - memcpy_fromio(&header, priv->base, sizeof(header));
186 - if (memcmp(header.magic, NVRAM_MAGIC, 4)) {
187 + if (memcmp(header->magic, NVRAM_MAGIC, 4)) {
188 dev_err(dev, "Invalid NVRAM magic\n");
192 - len = le32_to_cpu(header.len);
194 - data = kzalloc(len, GFP_KERNEL);
198 - memcpy_fromio(data, priv->base, len);
199 - data[len - 1] = '\0';
201 - err = brcm_nvram_add_cells(priv, data, len);
203 - dev_err(dev, "Failed to add cells: %d\n", err);
205 + len = le32_to_cpu(header->len);
206 + if (len > priv->nvmem_size) {
207 + dev_err(dev, "NVRAM length (%zd) exceeds mapped size (%zd)\n", len, priv->nvmem_size);
212 + err = brcm_nvram_add_cells(priv, priv->data, len);
214 + dev_err(dev, "Failed to add cells: %d\n", err);
218 @@ -150,7 +203,6 @@ static int brcm_nvram_probe(struct platf
219 .reg_read = brcm_nvram_read,
221 struct device *dev = &pdev->dev;
222 - struct resource *res;
223 struct brcm_nvram *priv;
226 @@ -159,21 +211,19 @@ static int brcm_nvram_probe(struct platf
230 - priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
231 - if (IS_ERR(priv->base))
232 - return PTR_ERR(priv->base);
233 + err = brcm_nvram_copy_data(priv, pdev);
237 err = brcm_nvram_parse(priv);
241 - bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res));
244 config.cells = priv->cells;
245 config.ncells = priv->ncells;
247 - config.size = resource_size(res);
248 + config.size = priv->nvmem_size;
250 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));