+++ /dev/null
-From f955dc14450695564926711cf9fa8e1d5d854302 Mon Sep 17 00:00:00 2001
-From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
-Date: Wed, 15 Jun 2022 21:43:00 +0200
-Subject: [PATCH] nvmem: add driver handling U-Boot environment variables
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-U-Boot stores its setup as environment variables. It's a list of
-key-value pairs stored on flash device with a custom header.
-
-This commit adds an NVMEM driver that:
-1. Provides NVMEM access to environment vars binary data
-2. Extracts variables as NVMEM cells
-
-Current Linux's NVMEM sysfs API allows reading whole NVMEM data block.
-It can be used by user-space tools for reading U-Boot env vars block
-without the hassle of finding its location. Parsing will still need to
-be re-done there.
-
-Kernel-parsed NVMEM cells can be read however by Linux drivers. This may
-be useful for Ethernet drivers for reading device MAC address which is
-often stored as U-Boot env variable.
-
-Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
-Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
-Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
----
-
---- a/drivers/nvmem/Kconfig
-+++ b/drivers/nvmem/Kconfig
-@@ -270,4 +270,17 @@ config SPRD_EFUSE
- This driver can also be built as a module. If so, the module
- will be called nvmem-sprd-efuse.
-
-+config NVMEM_U_BOOT_ENV
-+ tristate "U-Boot environment variables support"
-+ depends on OF && MTD
-+ select CRC32
-+ help
-+ U-Boot stores its setup as environment variables. This driver adds
-+ support for verifying & exporting such data. It also exposes variables
-+ as NVMEM cells so they can be referenced by other drivers.
-+
-+ Currently this drivers works only with env variables on top of MTD.
-+
-+ If compiled as module it will be called nvmem_u-boot-env.
-+
- endif
---- a/drivers/nvmem/Makefile
-+++ b/drivers/nvmem/Makefile
-@@ -55,3 +55,5 @@ obj-$(CONFIG_NVMEM_ZYNQMP) += nvmem_zynq
- nvmem_zynqmp_nvmem-y := zynqmp_nvmem.o
- obj-$(CONFIG_SPRD_EFUSE) += nvmem_sprd_efuse.o
- nvmem_sprd_efuse-y := sprd-efuse.o
-+obj-$(CONFIG_NVMEM_U_BOOT_ENV) += nvmem_u-boot-env.o
-+nvmem_u-boot-env-y := u-boot-env.o
---- /dev/null
-+++ b/drivers/nvmem/u-boot-env.c
-@@ -0,0 +1,218 @@
-+// SPDX-License-Identifier: GPL-2.0-only
-+/*
-+ * Copyright (C) 2022 Rafał Miłecki <rafal@milecki.pl>
-+ */
-+
-+#include <linux/crc32.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_device.h>
-+#include <linux/platform_device.h>
-+#include <linux/slab.h>
-+
-+enum u_boot_env_format {
-+ U_BOOT_FORMAT_SINGLE,
-+ U_BOOT_FORMAT_REDUNDANT,
-+};
-+
-+struct u_boot_env {
-+ struct device *dev;
-+ enum u_boot_env_format format;
-+
-+ struct mtd_info *mtd;
-+
-+ /* Cells */
-+ struct nvmem_cell_info *cells;
-+ int ncells;
-+};
-+
-+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;
-+
-+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_add_cells(struct u_boot_env *priv, uint8_t *buf,
-+ size_t data_offset, size_t data_len)
-+{
-+ struct device *dev = priv->dev;
-+ char *data = buf + data_offset;
-+ char *var, *value, *eq;
-+ int idx;
-+
-+ priv->ncells = 0;
-+ for (var = data; var < data + data_len && *var; var += strlen(var) + 1)
-+ priv->ncells++;
-+
-+ priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
-+ if (!priv->cells)
-+ return -ENOMEM;
-+
-+ for (var = data, idx = 0;
-+ var < data + data_len && *var;
-+ var = value + strlen(value) + 1, idx++) {
-+ eq = strchr(var, '=');
-+ if (!eq)
-+ break;
-+ *eq = '\0';
-+ value = eq + 1;
-+
-+ priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
-+ if (!priv->cells[idx].name)
-+ return -ENOMEM;
-+ priv->cells[idx].offset = data_offset + value - data;
-+ priv->cells[idx].bytes = strlen(value);
-+ }
-+
-+ if (WARN_ON(idx != priv->ncells))
-+ priv->ncells = idx;
-+
-+ return 0;
-+}
-+
-+static int u_boot_env_parse(struct u_boot_env *priv)
-+{
-+ struct device *dev = priv->dev;
-+ size_t crc32_data_offset;
-+ size_t crc32_data_len;
-+ size_t crc32_offset;
-+ size_t data_offset;
-+ size_t data_len;
-+ uint32_t crc32;
-+ uint32_t calc;
-+ size_t bytes;
-+ uint8_t *buf;
-+ int err;
-+
-+ buf = kcalloc(1, priv->mtd->size, GFP_KERNEL);
-+ if (!buf) {
-+ err = -ENOMEM;
-+ goto err_out;
-+ }
-+
-+ err = mtd_read(priv->mtd, 0, priv->mtd->size, &bytes, buf);
-+ if ((err && !mtd_is_bitflip(err)) || bytes != priv->mtd->size) {
-+ dev_err(dev, "Failed to read from mtd: %d\n", err);
-+ 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, mark);
-+ data_offset = offsetof(struct u_boot_env_image_redundant, data);
-+ break;
-+ }
-+ crc32 = le32_to_cpu(*(uint32_t *)(buf + crc32_offset));
-+ crc32_data_len = priv->mtd->size - crc32_data_offset;
-+ data_len = priv->mtd->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[priv->mtd->size - 1] = '\0';
-+ err = u_boot_env_add_cells(priv, buf, data_offset, data_len);
-+ if (err)
-+ dev_err(dev, "Failed to add cells: %d\n", err);
-+
-+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;
-+ int err;
-+
-+ 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);
-+ }
-+
-+ err = u_boot_env_parse(priv);
-+ if (err)
-+ return err;
-+
-+ config.dev = dev;
-+ config.cells = priv->cells;
-+ config.ncells = priv->ncells;
-+ config.priv = priv;
-+ config.size = priv->mtd->size;
-+
-+ return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
-+}
-+
-+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, },
-+ {},
-+};
-+
-+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);
projects / openwrt / staging / hauke.git / blobdiff