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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Copyright (C) 2021 Rafał Miłecki <[email protected]>
- */
- #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);
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