linux-stable/drivers/nvmem/u-boot-env.c
Rafał Miłecki 6bafe07c93 nvmem: u-boot-env: improve coding style
1. Prefer kzalloc() over kcalloc()
   See memory-allocation.rst which says: "to be on the safe side it's
   best to use routines that set memory to zero, like kzalloc()"
2. Drop dev_err() for u_boot_env_add_cells() fail
   It can fail only on -ENOMEM. We don't want to print error then.
3. Add extra "crc32_addr" variable
   It makes code reading header's crc32 easier to understand / review.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20231221173421.13737-5-zajec5@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-04 17:01:13 +01:00

253 lines
6 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2022 Rafał Miłecki <rafal@milecki.pl>
*/
#include <linux/crc32.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/nvmem-consumer.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
enum u_boot_env_format {
U_BOOT_FORMAT_SINGLE,
U_BOOT_FORMAT_REDUNDANT,
U_BOOT_FORMAT_BROADCOM,
};
struct u_boot_env {
struct device *dev;
struct nvmem_device *nvmem;
enum u_boot_env_format format;
struct mtd_info *mtd;
};
struct u_boot_env_image_single {
__le32 crc32;
uint8_t data[];
} __packed;
struct u_boot_env_image_redundant {
__le32 crc32;
u8 mark;
uint8_t data[];
} __packed;
struct u_boot_env_image_broadcom {
__le32 magic;
__le32 len;
__le32 crc32;
DECLARE_FLEX_ARRAY(uint8_t, data);
} __packed;
static int u_boot_env_read(void *context, unsigned int offset, void *val,
size_t bytes)
{
struct u_boot_env *priv = context;
struct device *dev = priv->dev;
size_t bytes_read;
int err;
err = mtd_read(priv->mtd, offset, bytes, &bytes_read, val);
if (err && !mtd_is_bitflip(err)) {
dev_err(dev, "Failed to read from mtd: %d\n", err);
return err;
}
if (bytes_read != bytes) {
dev_err(dev, "Failed to read %zu bytes\n", bytes);
return -EIO;
}
return 0;
}
static int u_boot_env_read_post_process_ethaddr(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 u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf,
size_t data_offset, size_t data_len)
{
struct nvmem_device *nvmem = priv->nvmem;
struct device *dev = priv->dev;
char *data = buf + data_offset;
char *var, *value, *eq;
for (var = data;
var < data + data_len && *var;
var = value + strlen(value) + 1) {
struct nvmem_cell_info info = {};
eq = strchr(var, '=');
if (!eq)
break;
*eq = '\0';
value = eq + 1;
info.name = devm_kstrdup(dev, var, GFP_KERNEL);
if (!info.name)
return -ENOMEM;
info.offset = data_offset + value - data;
info.bytes = strlen(value);
info.np = of_get_child_by_name(dev->of_node, info.name);
if (!strcmp(var, "ethaddr")) {
info.raw_len = strlen(value);
info.bytes = ETH_ALEN;
info.read_post_process = u_boot_env_read_post_process_ethaddr;
}
nvmem_add_one_cell(nvmem, &info);
}
return 0;
}
static int u_boot_env_parse(struct u_boot_env *priv)
{
struct nvmem_device *nvmem = priv->nvmem;
struct device *dev = priv->dev;
size_t crc32_data_offset;
size_t crc32_data_len;
size_t crc32_offset;
__le32 *crc32_addr;
size_t data_offset;
size_t data_len;
size_t dev_size;
uint32_t crc32;
uint32_t calc;
uint8_t *buf;
int bytes;
int err;
dev_size = nvmem_dev_size(nvmem);
buf = kzalloc(dev_size, GFP_KERNEL);
if (!buf) {
err = -ENOMEM;
goto err_out;
}
bytes = nvmem_device_read(nvmem, 0, dev_size, buf);
if (bytes < 0) {
err = bytes;
goto err_kfree;
} else if (bytes != dev_size) {
err = -EIO;
goto err_kfree;
}
switch (priv->format) {
case U_BOOT_FORMAT_SINGLE:
crc32_offset = offsetof(struct u_boot_env_image_single, crc32);
crc32_data_offset = offsetof(struct u_boot_env_image_single, data);
data_offset = offsetof(struct u_boot_env_image_single, data);
break;
case U_BOOT_FORMAT_REDUNDANT:
crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32);
crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data);
data_offset = offsetof(struct u_boot_env_image_redundant, data);
break;
case U_BOOT_FORMAT_BROADCOM:
crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32);
crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data);
data_offset = offsetof(struct u_boot_env_image_broadcom, data);
break;
}
crc32_addr = (__le32 *)(buf + crc32_offset);
crc32 = le32_to_cpu(*crc32_addr);
crc32_data_len = dev_size - crc32_data_offset;
data_len = dev_size - data_offset;
calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L;
if (calc != crc32) {
dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32);
err = -EINVAL;
goto err_kfree;
}
buf[dev_size - 1] = '\0';
err = u_boot_env_add_cells(priv, buf, data_offset, data_len);
err_kfree:
kfree(buf);
err_out:
return err;
}
static int u_boot_env_probe(struct platform_device *pdev)
{
struct nvmem_config config = {
.name = "u-boot-env",
.reg_read = u_boot_env_read,
};
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct u_boot_env *priv;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->dev = dev;
priv->format = (uintptr_t)of_device_get_match_data(dev);
priv->mtd = of_get_mtd_device_by_node(np);
if (IS_ERR(priv->mtd)) {
dev_err_probe(dev, PTR_ERR(priv->mtd), "Failed to get %pOF MTD\n", np);
return PTR_ERR(priv->mtd);
}
config.dev = dev;
config.priv = priv;
config.size = priv->mtd->size;
priv->nvmem = devm_nvmem_register(dev, &config);
if (IS_ERR(priv->nvmem))
return PTR_ERR(priv->nvmem);
return u_boot_env_parse(priv);
}
static const struct of_device_id u_boot_env_of_match_table[] = {
{ .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, },
{ .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
{ .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
{ .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, },
{},
};
static struct platform_driver u_boot_env_driver = {
.probe = u_boot_env_probe,
.driver = {
.name = "u_boot_env",
.of_match_table = u_boot_env_of_match_table,
},
};
module_platform_driver(u_boot_env_driver);
MODULE_AUTHOR("Rafał Miłecki");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);