diff options
Diffstat (limited to 'target/linux/generic/backport-5.4/802-v6.1-0001-nvmem-add-driver-handling-U-Boot-environment-variabl.patch')
| -rw-r--r-- | target/linux/generic/backport-5.4/802-v6.1-0001-nvmem-add-driver-handling-U-Boot-environment-variabl.patch | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.4/802-v6.1-0001-nvmem-add-driver-handling-U-Boot-environment-variabl.patch b/target/linux/generic/backport-5.4/802-v6.1-0001-nvmem-add-driver-handling-U-Boot-environment-variabl.patch new file mode 100644 index 0000000000..ef3c601753 --- /dev/null +++ b/target/linux/generic/backport-5.4/802-v6.1-0001-nvmem-add-driver-handling-U-Boot-environment-variabl.patch @@ -0,0 +1,278 @@ +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 +@@ -230,4 +230,17 @@ config NVMEM_ZYNQMP + + If sure, say yes. If unsure, say no. + ++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 +@@ -50,3 +50,5 @@ obj-$(CONFIG_SC27XX_EFUSE) += nvmem-sc27 + nvmem-sc27xx-efuse-y := sc27xx-efuse.o + obj-$(CONFIG_NVMEM_ZYNQMP) += nvmem_zynqmp_nvmem.o + nvmem_zynqmp_nvmem-y := zynqmp_nvmem.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(dev, "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); |