// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2021 Rafał Miłecki <[email protected]>
*/
#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_DESCRIPTION("Broadcom I/O-mapped NVRAM support driver");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);
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