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>
28 Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
30 drivers/nvmem/brcm_nvram.c | 134 ++++++++++++++++++++++++++-----------
31 1 file changed, 94 insertions(+), 40 deletions(-)
33 --- a/drivers/nvmem/brcm_nvram.c
34 +++ b/drivers/nvmem/brcm_nvram.c
37 #define NVRAM_MAGIC "FLSH"
40 + * struct brcm_nvram - driver state internal struct
42 + * @dev: NVMEM device pointer
43 + * @nvmem_size: Size of the whole space available for NVRAM
44 + * @data: NVRAM data copy stored to avoid poking underlaying flash controller
45 + * @data_len: NVRAM data size
46 + * @padding_byte: Padding value used to fill remaining space
47 + * @cells: Array of discovered NVMEM cells
48 + * @ncells: Number of elements in cells
56 + uint8_t padding_byte;
57 struct nvmem_cell_info *cells;
60 @@ -36,10 +50,47 @@ static int brcm_nvram_read(void *context
63 struct brcm_nvram *priv = context;
67 + if (offset + bytes > priv->data_len)
68 + to_copy = max_t(ssize_t, (ssize_t)priv->data_len - offset, 0);
72 + memcpy(val, priv->data + offset, to_copy);
74 + memset((uint8_t *)val + to_copy, priv->padding_byte, bytes - to_copy);
79 +static int brcm_nvram_copy_data(struct brcm_nvram *priv, struct platform_device *pdev)
81 + struct resource *res;
84 + base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
86 + return PTR_ERR(base);
88 + priv->nvmem_size = resource_size(res);
90 + priv->padding_byte = readb(base + priv->nvmem_size - 1);
91 + for (priv->data_len = priv->nvmem_size;
94 + if (readb(base + priv->data_len - 1) != priv->padding_byte)
97 + WARN(priv->data_len > SZ_128K, "Unexpected (big) NVRAM size: %zu B\n", priv->data_len);
100 - *dst++ = readb(priv->base + offset++);
101 + priv->data = devm_kzalloc(priv->dev, priv->data_len, GFP_KERNEL);
105 + memcpy_fromio(priv->data, base, priv->data_len);
107 + bcm47xx_nvram_init_from_iomem(base, priv->data_len);
111 @@ -67,8 +118,13 @@ static int brcm_nvram_add_cells(struct b
114 struct device *dev = priv->dev;
115 - char *var, *value, *eq;
121 + tmp = priv->data[len - 1];
122 + priv->data[len - 1] = '\0';
125 for (var = data + sizeof(struct brcm_nvram_header);
126 @@ -78,67 +134,68 @@ static int brcm_nvram_add_cells(struct b
129 priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
132 + if (!priv->cells) {
137 for (var = data + sizeof(struct brcm_nvram_header), idx = 0;
138 var < (char *)data + len && *var;
139 var = value + strlen(value) + 1, idx++) {
142 eq = strchr(var, '=');
146 + name = devm_kstrdup(dev, var, GFP_KERNEL);
154 - priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
155 - if (!priv->cells[idx].name)
157 + priv->cells[idx].name = name;
158 priv->cells[idx].offset = value - (char *)data;
159 priv->cells[idx].bytes = strlen(value);
160 priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
161 - if (!strcmp(var, "et0macaddr") ||
162 - !strcmp(var, "et1macaddr") ||
163 - !strcmp(var, "et2macaddr")) {
164 + if (!strcmp(name, "et0macaddr") ||
165 + !strcmp(name, "et1macaddr") ||
166 + !strcmp(name, "et2macaddr")) {
167 priv->cells[idx].raw_len = strlen(value);
168 priv->cells[idx].bytes = ETH_ALEN;
169 priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr;
175 + priv->data[len - 1] = tmp;
179 static int brcm_nvram_parse(struct brcm_nvram *priv)
181 + struct brcm_nvram_header *header = (struct brcm_nvram_header *)priv->data;
182 struct device *dev = priv->dev;
183 - struct brcm_nvram_header header;
188 - memcpy_fromio(&header, priv->base, sizeof(header));
190 - if (memcmp(header.magic, NVRAM_MAGIC, 4)) {
191 + if (memcmp(header->magic, NVRAM_MAGIC, 4)) {
192 dev_err(dev, "Invalid NVRAM magic\n");
196 - len = le32_to_cpu(header.len);
198 - data = kzalloc(len, GFP_KERNEL);
202 - memcpy_fromio(data, priv->base, len);
203 - data[len - 1] = '\0';
205 - err = brcm_nvram_add_cells(priv, data, len);
207 - dev_err(dev, "Failed to add cells: %d\n", err);
209 + len = le32_to_cpu(header->len);
210 + if (len > priv->nvmem_size) {
211 + dev_err(dev, "NVRAM length (%zd) exceeds mapped size (%zd)\n", len,
217 + err = brcm_nvram_add_cells(priv, priv->data, len);
219 + dev_err(dev, "Failed to add cells: %d\n", err);
223 @@ -150,7 +207,6 @@ static int brcm_nvram_probe(struct platf
224 .reg_read = brcm_nvram_read,
226 struct device *dev = &pdev->dev;
227 - struct resource *res;
228 struct brcm_nvram *priv;
231 @@ -159,21 +215,19 @@ static int brcm_nvram_probe(struct platf
235 - priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
236 - if (IS_ERR(priv->base))
237 - return PTR_ERR(priv->base);
238 + err = brcm_nvram_copy_data(priv, pdev);
242 err = brcm_nvram_parse(priv);
246 - bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res));
249 config.cells = priv->cells;
250 config.ncells = priv->ncells;
252 - config.size = resource_size(res);
253 + config.size = priv->nvmem_size;
255 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));