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![Rafał Miłecki](/assets/img/avatar_default.png)
Broadcom uses U-Boot for a lot of their bcmbca familiy chipsets. They
decided to store U-Boot environment data inside U-Boot partition and to
use a custom header (with "uEnv" magic and env data length).
Add support for Broadcom's specific binding and their custom format.
Ref: 6b0584c19d
("dt-bindings: nvmem: u-boot,env: add Broadcom's variant binding")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20221118063932.6418-9-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
233 lines
5.7 KiB
C
233 lines
5.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2022 Rafał Miłecki <rafal@milecki.pl>
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*/
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#include <linux/crc32.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/mtd/mtd.h>
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#include <linux/nvmem-consumer.h>
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#include <linux/nvmem-provider.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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enum u_boot_env_format {
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U_BOOT_FORMAT_SINGLE,
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U_BOOT_FORMAT_REDUNDANT,
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U_BOOT_FORMAT_BROADCOM,
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};
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struct u_boot_env {
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struct device *dev;
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enum u_boot_env_format format;
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struct mtd_info *mtd;
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/* Cells */
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struct nvmem_cell_info *cells;
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int ncells;
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};
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struct u_boot_env_image_single {
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__le32 crc32;
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uint8_t data[];
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} __packed;
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struct u_boot_env_image_redundant {
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__le32 crc32;
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u8 mark;
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uint8_t data[];
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} __packed;
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struct u_boot_env_image_broadcom {
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__le32 magic;
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__le32 len;
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__le32 crc32;
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uint8_t data[0];
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} __packed;
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static int u_boot_env_read(void *context, unsigned int offset, void *val,
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size_t bytes)
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{
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struct u_boot_env *priv = context;
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struct device *dev = priv->dev;
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size_t bytes_read;
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int err;
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err = mtd_read(priv->mtd, offset, bytes, &bytes_read, val);
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if (err && !mtd_is_bitflip(err)) {
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dev_err(dev, "Failed to read from mtd: %d\n", err);
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return err;
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}
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if (bytes_read != bytes) {
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dev_err(dev, "Failed to read %zu bytes\n", bytes);
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return -EIO;
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}
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return 0;
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}
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static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf,
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size_t data_offset, size_t data_len)
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{
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struct device *dev = priv->dev;
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char *data = buf + data_offset;
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char *var, *value, *eq;
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int idx;
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priv->ncells = 0;
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for (var = data; var < data + data_len && *var; var += strlen(var) + 1)
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priv->ncells++;
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priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
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if (!priv->cells)
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return -ENOMEM;
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for (var = data, idx = 0;
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var < data + data_len && *var;
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var = value + strlen(value) + 1, idx++) {
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eq = strchr(var, '=');
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if (!eq)
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break;
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*eq = '\0';
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value = eq + 1;
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priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
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if (!priv->cells[idx].name)
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return -ENOMEM;
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priv->cells[idx].offset = data_offset + value - data;
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priv->cells[idx].bytes = strlen(value);
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priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
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}
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if (WARN_ON(idx != priv->ncells))
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priv->ncells = idx;
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return 0;
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}
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static int u_boot_env_parse(struct u_boot_env *priv)
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{
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struct device *dev = priv->dev;
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size_t crc32_data_offset;
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size_t crc32_data_len;
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size_t crc32_offset;
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size_t data_offset;
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size_t data_len;
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uint32_t crc32;
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uint32_t calc;
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size_t bytes;
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uint8_t *buf;
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int err;
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buf = kcalloc(1, priv->mtd->size, GFP_KERNEL);
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if (!buf) {
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err = -ENOMEM;
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goto err_out;
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}
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err = mtd_read(priv->mtd, 0, priv->mtd->size, &bytes, buf);
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if ((err && !mtd_is_bitflip(err)) || bytes != priv->mtd->size) {
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dev_err(dev, "Failed to read from mtd: %d\n", err);
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goto err_kfree;
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}
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switch (priv->format) {
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case U_BOOT_FORMAT_SINGLE:
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crc32_offset = offsetof(struct u_boot_env_image_single, crc32);
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crc32_data_offset = offsetof(struct u_boot_env_image_single, data);
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data_offset = offsetof(struct u_boot_env_image_single, data);
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break;
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case U_BOOT_FORMAT_REDUNDANT:
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crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32);
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crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data);
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data_offset = offsetof(struct u_boot_env_image_redundant, data);
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break;
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case U_BOOT_FORMAT_BROADCOM:
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crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32);
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crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data);
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data_offset = offsetof(struct u_boot_env_image_broadcom, data);
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break;
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}
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crc32 = le32_to_cpu(*(__le32 *)(buf + crc32_offset));
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crc32_data_len = priv->mtd->size - crc32_data_offset;
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data_len = priv->mtd->size - data_offset;
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calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L;
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if (calc != crc32) {
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dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32);
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err = -EINVAL;
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goto err_kfree;
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}
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buf[priv->mtd->size - 1] = '\0';
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err = u_boot_env_add_cells(priv, buf, data_offset, data_len);
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if (err)
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dev_err(dev, "Failed to add cells: %d\n", err);
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err_kfree:
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kfree(buf);
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err_out:
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return err;
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}
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static int u_boot_env_probe(struct platform_device *pdev)
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{
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struct nvmem_config config = {
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.name = "u-boot-env",
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.reg_read = u_boot_env_read,
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};
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct u_boot_env *priv;
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int err;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->dev = dev;
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priv->format = (uintptr_t)of_device_get_match_data(dev);
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priv->mtd = of_get_mtd_device_by_node(np);
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if (IS_ERR(priv->mtd)) {
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dev_err_probe(dev, PTR_ERR(priv->mtd), "Failed to get %pOF MTD\n", np);
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return PTR_ERR(priv->mtd);
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}
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err = u_boot_env_parse(priv);
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if (err)
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return err;
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config.dev = dev;
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config.cells = priv->cells;
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config.ncells = priv->ncells;
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config.priv = priv;
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config.size = priv->mtd->size;
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return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
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}
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static const struct of_device_id u_boot_env_of_match_table[] = {
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{ .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, },
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{ .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
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{ .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
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{ .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, },
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{},
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};
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static struct platform_driver u_boot_env_driver = {
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.probe = u_boot_env_probe,
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.driver = {
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.name = "u_boot_env",
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.of_match_table = u_boot_env_of_match_table,
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},
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};
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module_platform_driver(u_boot_env_driver);
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MODULE_AUTHOR("Rafał Miłecki");
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MODULE_LICENSE("GPL");
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MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);
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