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// 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/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);
}
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 = kcalloc(1, len, GFP_KERNEL);
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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