This is a note to let you know that I've just added the patch titled
nvmem: brcm_nvram: store a copy of NVRAM content
to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.
If you have any questions about this process, please let me know.
From 1e37bf84afacd5ba17b7a13a18ca2bc78aff05c0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= rafal@milecki.pl Date: Fri, 15 Dec 2023 11:13:58 +0000 Subject: nvmem: brcm_nvram: store a copy of NVRAM content MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
This driver uses MMIO access for reading NVRAM from a flash device. Underneath there is a flash controller that reads data and provides mapping window.
Using MMIO interface affects controller configuration and may break real controller driver. It was reported by multiple users of devices with NVRAM stored on NAND.
Modify driver to read & cache NVRAM content during init and use that copy to provide NVMEM data when requested. On NAND flashes due to their alignment NVRAM partitions can be quite big (1 MiB and more) while actual NVRAM content stays quite small (usually 16 to 32 KiB). To avoid allocating so much memory check for actual data length.
Link: https://lore.kernel.org/linux-mtd/CACna6rwf3_9QVjYcM+847biTX=K0EoWXuXcSMkJO1... Fixes: 3fef9ed0627a ("nvmem: brcm_nvram: new driver exposing Broadcom's NVRAM") Cc: Stable@vger.kernel.org Cc: Arınç ÜNAL arinc.unal@arinc9.com Cc: Florian Fainelli florian.fainelli@broadcom.com Cc: Scott Branden scott.branden@broadcom.com Signed-off-by: Rafał Miłecki rafal@milecki.pl Acked-by: Arınç ÜNAL arinc.unal@arinc9.com Signed-off-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org Link: https://lore.kernel.org/r/20231215111358.316727-3-srinivas.kandagatla@linaro... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/nvmem/brcm_nvram.c | 134 ++++++++++++++++++++++++++----------- 1 file changed, 94 insertions(+), 40 deletions(-)
diff --git a/drivers/nvmem/brcm_nvram.c b/drivers/nvmem/brcm_nvram.c index 9737104f3b76..5cdf339cfbec 100644 --- a/drivers/nvmem/brcm_nvram.c +++ b/drivers/nvmem/brcm_nvram.c @@ -17,9 +17,23 @@
#define NVRAM_MAGIC "FLSH"
+/** + * struct brcm_nvram - driver state internal struct + * + * @dev: NVMEM device pointer + * @nvmem_size: Size of the whole space available for NVRAM + * @data: NVRAM data copy stored to avoid poking underlaying flash controller + * @data_len: NVRAM data size + * @padding_byte: Padding value used to fill remaining space + * @cells: Array of discovered NVMEM cells + * @ncells: Number of elements in cells + */ struct brcm_nvram { struct device *dev; - void __iomem *base; + size_t nvmem_size; + uint8_t *data; + size_t data_len; + uint8_t padding_byte; struct nvmem_cell_info *cells; int ncells; }; @@ -36,10 +50,47 @@ static int brcm_nvram_read(void *context, unsigned int offset, void *val, size_t bytes) { struct brcm_nvram *priv = context; - u8 *dst = val; + size_t to_copy;
- while (bytes--) - *dst++ = readb(priv->base + offset++); + if (offset + bytes > priv->data_len) + to_copy = max_t(ssize_t, (ssize_t)priv->data_len - offset, 0); + else + to_copy = bytes; + + memcpy(val, priv->data + offset, to_copy); + + memset((uint8_t *)val + to_copy, priv->padding_byte, bytes - to_copy); + + return 0; +} + +static int brcm_nvram_copy_data(struct brcm_nvram *priv, struct platform_device *pdev) +{ + struct resource *res; + void __iomem *base; + + base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(base)) + return PTR_ERR(base); + + priv->nvmem_size = resource_size(res); + + priv->padding_byte = readb(base + priv->nvmem_size - 1); + for (priv->data_len = priv->nvmem_size; + priv->data_len; + priv->data_len--) { + if (readb(base + priv->data_len - 1) != priv->padding_byte) + break; + } + WARN(priv->data_len > SZ_128K, "Unexpected (big) NVRAM size: %zu B\n", priv->data_len); + + priv->data = devm_kzalloc(priv->dev, priv->data_len, GFP_KERNEL); + if (!priv->data) + return -ENOMEM; + + memcpy_fromio(priv->data, base, priv->data_len); + + bcm47xx_nvram_init_from_iomem(base, priv->data_len);
return 0; } @@ -67,8 +118,13 @@ static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data, size_t len) { struct device *dev = priv->dev; - char *var, *value, *eq; + char *var, *value; + uint8_t tmp; int idx; + int err = 0; + + tmp = priv->data[len - 1]; + priv->data[len - 1] = '\0';
priv->ncells = 0; for (var = data + sizeof(struct brcm_nvram_header); @@ -78,67 +134,68 @@ static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data, }
priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL); - if (!priv->cells) - return -ENOMEM; + if (!priv->cells) { + err = -ENOMEM; + goto out; + }
for (var = data + sizeof(struct brcm_nvram_header), idx = 0; var < (char *)data + len && *var; var = value + strlen(value) + 1, idx++) { + char *eq, *name; + eq = strchr(var, '='); if (!eq) break; *eq = '\0'; + name = devm_kstrdup(dev, var, GFP_KERNEL); + *eq = '='; + if (!name) { + err = -ENOMEM; + goto out; + } value = eq + 1;
- priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL); - if (!priv->cells[idx].name) - return -ENOMEM; + priv->cells[idx].name = name; priv->cells[idx].offset = value - (char *)data; priv->cells[idx].bytes = strlen(value); priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name); - if (!strcmp(var, "et0macaddr") || - !strcmp(var, "et1macaddr") || - !strcmp(var, "et2macaddr")) { + if (!strcmp(name, "et0macaddr") || + !strcmp(name, "et1macaddr") || + !strcmp(name, "et2macaddr")) { priv->cells[idx].raw_len = strlen(value); priv->cells[idx].bytes = ETH_ALEN; priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr; } }
- return 0; +out: + priv->data[len - 1] = tmp; + return err; }
static int brcm_nvram_parse(struct brcm_nvram *priv) { + struct brcm_nvram_header *header = (struct brcm_nvram_header *)priv->data; struct device *dev = priv->dev; - struct brcm_nvram_header header; - uint8_t *data; size_t len; int err;
- memcpy_fromio(&header, priv->base, sizeof(header)); - - if (memcmp(header.magic, NVRAM_MAGIC, 4)) { + if (memcmp(header->magic, NVRAM_MAGIC, 4)) { dev_err(dev, "Invalid NVRAM magic\n"); return -EINVAL; }
- len = le32_to_cpu(header.len); - - data = kzalloc(len, GFP_KERNEL); - if (!data) - return -ENOMEM; - - memcpy_fromio(data, priv->base, len); - data[len - 1] = '\0'; - - err = brcm_nvram_add_cells(priv, data, len); - if (err) { - dev_err(dev, "Failed to add cells: %d\n", err); - return err; + len = le32_to_cpu(header->len); + if (len > priv->nvmem_size) { + dev_err(dev, "NVRAM length (%zd) exceeds mapped size (%zd)\n", len, + priv->nvmem_size); + return -EINVAL; }
- kfree(data); + err = brcm_nvram_add_cells(priv, priv->data, len); + if (err) + dev_err(dev, "Failed to add cells: %d\n", err);
return 0; } @@ -150,7 +207,6 @@ static int brcm_nvram_probe(struct platform_device *pdev) .reg_read = brcm_nvram_read, }; struct device *dev = &pdev->dev; - struct resource *res; struct brcm_nvram *priv; int err;
@@ -159,21 +215,19 @@ static int brcm_nvram_probe(struct platform_device *pdev) return -ENOMEM; priv->dev = dev;
- priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); - if (IS_ERR(priv->base)) - return PTR_ERR(priv->base); + err = brcm_nvram_copy_data(priv, pdev); + if (err) + return err;
err = brcm_nvram_parse(priv); if (err) return err;
- bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res)); - config.dev = dev; config.cells = priv->cells; config.ncells = priv->ncells; config.priv = priv; - config.size = resource_size(res); + config.size = priv->nvmem_size;
return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); }