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1// SPDX-License-Identifier: GPL-2.0-only2/*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);101