diff options
Diffstat (limited to 'drivers/nvmem/brcm_nvram.c')
| -rw-r--r-- | drivers/nvmem/brcm_nvram.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/drivers/nvmem/brcm_nvram.c b/drivers/nvmem/brcm_nvram.c new file mode 100644 index 000000000..5cdf339cf --- /dev/null +++ b/drivers/nvmem/brcm_nvram.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl> + */ + +#include <linux/bcm47xx_nvram.h> +#include <linux/etherdevice.h> +#include <linux/if_ether.h> +#include <linux/io.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/nvmem-consumer.h> +#include <linux/nvmem-provider.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +#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; + size_t nvmem_size; + uint8_t *data; + size_t data_len; + uint8_t padding_byte; + struct nvmem_cell_info *cells; + int ncells; +}; + +struct brcm_nvram_header { + char magic[4]; + __le32 len; + __le32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */ + __le32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */ + __le32 config_ncdl; /* ncdl values for memc */ +}; + +static int brcm_nvram_read(void *context, unsigned int offset, void *val, + size_t bytes) +{ + struct brcm_nvram *priv = context; + size_t to_copy; + + 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; +} + +static int brcm_nvram_read_post_process_macaddr(void *context, const char *id, int index, + unsigned int offset, void *buf, size_t bytes) +{ + u8 mac[ETH_ALEN]; + + if (bytes != 3 * ETH_ALEN - 1) + return -EINVAL; + + if (!mac_pton(buf, mac)) + return -EINVAL; + + if (index) + eth_addr_add(mac, index); + + ether_addr_copy(buf, mac); + + return 0; +} + +static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data, + size_t len) +{ + struct device *dev = priv->dev; + 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); + var < (char *)data + len && *var; + var += strlen(var) + 1) { + priv->ncells++; + } + + priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL); + 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 = 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(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; + } + } + +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; + size_t len; + int err; + + if (memcmp(header->magic, NVRAM_MAGIC, 4)) { + dev_err(dev, "Invalid NVRAM magic\n"); + return -EINVAL; + } + + 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; + } + + err = brcm_nvram_add_cells(priv, priv->data, len); + if (err) + dev_err(dev, "Failed to add cells: %d\n", err); + + return 0; +} + +static int brcm_nvram_probe(struct platform_device *pdev) +{ + struct nvmem_config config = { + .name = "brcm-nvram", + .reg_read = brcm_nvram_read, + }; + struct device *dev = &pdev->dev; + struct brcm_nvram *priv; + int err; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + priv->dev = dev; + + err = brcm_nvram_copy_data(priv, pdev); + if (err) + return err; + + err = brcm_nvram_parse(priv); + if (err) + return err; + + config.dev = dev; + config.cells = priv->cells; + config.ncells = priv->ncells; + config.priv = priv; + config.size = priv->nvmem_size; + + return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); +} + +static const struct of_device_id brcm_nvram_of_match_table[] = { + { .compatible = "brcm,nvram", }, + {}, +}; + +static struct platform_driver brcm_nvram_driver = { + .probe = brcm_nvram_probe, + .driver = { + .name = "brcm_nvram", + .of_match_table = brcm_nvram_of_match_table, + }, +}; + +static int __init brcm_nvram_init(void) +{ + return platform_driver_register(&brcm_nvram_driver); +} + +subsys_initcall_sync(brcm_nvram_init); + +MODULE_AUTHOR("Rafał Miłecki"); +MODULE_LICENSE("GPL"); +MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table); 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