Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2022 Rafał Miłecki <rafal@milecki.pl>
4 */
5
6#include <linux/mod_devicetable.h>
7#include <linux/module.h>
8#include <linux/mtd/mtd.h>
9#include <linux/nvmem-provider.h>
10#include <linux/of.h>
11#include <linux/platform_device.h>
12#include <linux/slab.h>
13
14#include "layouts/u-boot-env.h"
15
16struct u_boot_env {
17 struct device *dev;
18 struct nvmem_device *nvmem;
19 enum u_boot_env_format format;
20
21 struct mtd_info *mtd;
22};
23
24static int u_boot_env_read(void *context, unsigned int offset, void *val,
25 size_t bytes)
26{
27 struct u_boot_env *priv = context;
28 struct device *dev = priv->dev;
29 size_t bytes_read;
30 int err;
31
32 err = mtd_read(priv->mtd, offset, bytes, &bytes_read, val);
33 if (err && !mtd_is_bitflip(err)) {
34 dev_err(dev, "Failed to read from mtd: %d\n", err);
35 return err;
36 }
37
38 if (bytes_read != bytes) {
39 dev_err(dev, "Failed to read %zu bytes\n", bytes);
40 return -EIO;
41 }
42
43 return 0;
44}
45
46static int u_boot_env_probe(struct platform_device *pdev)
47{
48 struct nvmem_config config = {
49 .name = "u-boot-env",
50 .reg_read = u_boot_env_read,
51 };
52 struct device *dev = &pdev->dev;
53 struct device_node *np = dev->of_node;
54 struct u_boot_env *priv;
55
56 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
57 if (!priv)
58 return -ENOMEM;
59 priv->dev = dev;
60
61 priv->format = (uintptr_t)of_device_get_match_data(dev);
62
63 priv->mtd = of_get_mtd_device_by_node(np);
64 if (IS_ERR(priv->mtd)) {
65 dev_err_probe(dev, PTR_ERR(priv->mtd), "Failed to get %pOF MTD\n", np);
66 return PTR_ERR(priv->mtd);
67 }
68
69 config.dev = dev;
70 config.priv = priv;
71 config.size = priv->mtd->size;
72
73 priv->nvmem = devm_nvmem_register(dev, &config);
74 if (IS_ERR(priv->nvmem))
75 return PTR_ERR(priv->nvmem);
76
77 return u_boot_env_parse(dev, priv->nvmem, priv->format);
78}
79
80static const struct of_device_id u_boot_env_of_match_table[] = {
81 { .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, },
82 { .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
83 { .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
84 { .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, },
85 {},
86};
87
88static struct platform_driver u_boot_env_driver = {
89 .probe = u_boot_env_probe,
90 .driver = {
91 .name = "u_boot_env",
92 .of_match_table = u_boot_env_of_match_table,
93 },
94};
95module_platform_driver(u_boot_env_driver);
96
97MODULE_AUTHOR("Rafał Miłecki");
98MODULE_DESCRIPTION("U-Boot environment variables support module");
99MODULE_LICENSE("GPL");
100MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);