diff options
Diffstat (limited to 'drivers/nvmem/brcm_nvram.c')
| -rw-r--r-- | drivers/nvmem/brcm_nvram.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/nvmem/brcm_nvram.c b/drivers/nvmem/brcm_nvram.c new file mode 100644 index 000000000..7bd65fc29 --- /dev/null +++ b/drivers/nvmem/brcm_nvram.c @@ -0,0 +1,173 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl> + */ + +#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 { + struct device *dev; + void __iomem *base; + 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; + u8 *dst = val; + + while (bytes--) + *dst++ = readb(priv->base + offset++); + + 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, *eq; + int idx; + + 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) + return -ENOMEM; + + for (var = data + sizeof(struct brcm_nvram_header), idx = 0; + var < (char *)data + len && *var; + var = value + strlen(value) + 1, idx++) { + eq = strchr(var, '='); + if (!eq) + break; + *eq = '\0'; + value = eq + 1; + + priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL); + if (!priv->cells[idx].name) + return -ENOMEM; + 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); + } + + return 0; +} + +static int brcm_nvram_parse(struct brcm_nvram *priv) +{ + 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)) { + 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; + } + + kfree(data); + + 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 resource *res; + struct brcm_nvram *priv; + int err; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + priv->dev = dev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->base = devm_ioremap_resource(dev, res); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + 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 = resource_size(res); + + 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); |