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[194.187.74.233]) by smtp.gmail.com with ESMTPSA id d5sm2440007lfl.242.2021.12.30.01.05.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Dec 2021 01:05:02 -0800 (PST) From: =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= To: Srinivas Kandagatla , Rob Herring , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= Subject: [PATCH V2 3/3] nvmem: add driver handling U-Boot environment variables Date: Thu, 30 Dec 2021 10:04:49 +0100 Message-Id: <20211230090449.11808-3-zajec5@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211230090449.11808-1-zajec5@gmail.com> References: <20211230090449.11808-1-zajec5@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org From: Rafał Miłecki U-Boot binary contains a block of environment variables (NVMEM) that should be parsed and exposed as NVMEM cells. Signed-off-by: Rafał Miłecki --- V2: Drop debugging dev_info() call Fix variable type mismatch --- MAINTAINERS | 1 + drivers/nvmem/Kconfig | 10 ++ drivers/nvmem/Makefile | 2 + drivers/nvmem/u-boot-env.c | 235 +++++++++++++++++++++++++++++++++++++ 4 files changed, 248 insertions(+) create mode 100644 drivers/nvmem/u-boot-env.c diff --git a/MAINTAINERS b/MAINTAINERS index 271c29c84c7d..cc9bdeb33b64 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -19628,6 +19628,7 @@ U-BOOT ENVIRONMENT VARIABLES M: Rafał Miłecki S: Maintained F: Documentation/devicetree/bindings/nvmem/u-boot,env.yaml +F: drivers/nvmem/u-boot-env.c UACCE ACCELERATOR FRAMEWORK M: Zhangfei Gao diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index da414617a54d..af9115852412 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -300,4 +300,14 @@ config NVMEM_BRCM_NVRAM This driver provides support for Broadcom's NVRAM that can be accessed using I/O mapping. +config NVMEM_U_BOOT_ENV + tristate "U-Boot environment variables support" + depends on ARCH_BCM4908 || COMPILE_TEST + depends on OF + help + This driver adds support for parsing U-Boot environment variables + stored on flash partition. + + If compiled as module it will be called nvmem_u-boot-env. + endif diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index dcbbde35b6a8..772904cdebdb 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -61,3 +61,5 @@ obj-$(CONFIG_NVMEM_RMEM) += nvmem-rmem.o nvmem-rmem-y := rmem.o obj-$(CONFIG_NVMEM_BRCM_NVRAM) += nvmem_brcm_nvram.o nvmem_brcm_nvram-y := brcm_nvram.o +obj-$(CONFIG_NVMEM_U_BOOT_ENV) += nvmem_u-boot-env.o +nvmem_u-boot-env-y := u-boot-env.o diff --git a/drivers/nvmem/u-boot-env.c b/drivers/nvmem/u-boot-env.c new file mode 100644 index 000000000000..42626c552d37 --- /dev/null +++ b/drivers/nvmem/u-boot-env.c @@ -0,0 +1,235 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2021 Rafał Miłecki + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +enum u_boot_env_format { + U_BOOT_FORMAT_DEFAULT, + U_BOOT_FORMAT_BRCM, +}; + +struct u_boot_env { + struct device *dev; + enum u_boot_env_format format; + struct mtd_info *mtd; + size_t offset; + size_t size; + struct nvmem_cell_info *cells; + int ncells; +}; + +struct u_boot_env_image { + __le32 crc32; + uint8_t data[0]; +} __packed; + +struct u_boot_brcm_header { + __le32 unk; + __le32 len; +} __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, priv->offset + 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 %zd bytes\n", bytes); + return err; + } + + return 0; +} + +static int u_boot_env_add_cells(struct u_boot_env *priv, size_t data_offset, + uint8_t *data, size_t len) +{ + struct device *dev = priv->dev; + char *var, *value, *eq; + int idx; + + priv->ncells = 0; + for (var = data; var < (char *)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 < (char *)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 - (char *)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; + struct u_boot_env_image *image; + size_t image_offset; + size_t image_len; + uint32_t crc32; + size_t bytes; + uint8_t *buf; + int err; + + image_offset = 0; + image_len = priv->size; + if (priv->format == U_BOOT_FORMAT_BRCM) { + struct u_boot_brcm_header header; + + err = mtd_read(priv->mtd, priv->offset, sizeof(header), &bytes, + (uint8_t *)&header); + if (err && !mtd_is_bitflip(err)) { + dev_err(dev, "Failed to read from mtd: %d\n", err); + return err; + } + + image_offset = sizeof(header); + image_len = le32_to_cpu(header.len); + } + + buf = kcalloc(1, image_len, GFP_KERNEL); + if (!buf) { + err = -ENOMEM; + goto err_out; + } + image = (struct u_boot_env_image *)buf; + + err = mtd_read(priv->mtd, priv->offset + image_offset, image_len, &bytes, buf); + if (err && !mtd_is_bitflip(err)) { + dev_err(dev, "Failed to read from mtd: %d\n", err); + goto err_kfree; + } + + crc32 = crc32(~0, buf + 4, image_len - 4) ^ ~0L; + if (crc32 != le32_to_cpu(image->crc32)) { + dev_err(dev, "Invalid calculated CRC32: 0x%08x\n", crc32); + err = -EINVAL; + goto err_kfree; + } + + buf[image_len - 1] = '\0'; + err = u_boot_env_add_cells(priv, image_offset + sizeof(*image), + buf + sizeof(*image), + image_len - sizeof(*image)); + if (err) + dev_err(dev, "Failed to add cells: %d\n", err); + +err_kfree: + kfree(buf); +err_out: + return err; +} + +static const struct of_device_id u_boot_env_of_match_table[] = { + { .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_DEFAULT, }, + { .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BRCM, }, + {}, +}; + +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; + const struct of_device_id *of_id; + struct u_boot_env *priv; + const char *label; + int err; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + priv->dev = dev; + + of_id = of_match_device(u_boot_env_of_match_table, dev); + if (!of_id) + return -EINVAL; + priv->format = (uintptr_t)of_id->data; + + if (of_property_read_u32(np, "reg", (u32 *)&priv->offset) || + of_property_read_u32_index(np, "reg", 1, (u32 *)&priv->size)) { + dev_err(dev, "Failed to read \"reg\" property\n"); + return -EINVAL; + } + + label = of_get_property(np->parent, "label", NULL); + if (!label) + label = np->parent->name; + + priv->mtd = get_mtd_device_nm(label); + if (IS_ERR(priv->mtd)) { + dev_err(dev, "Failed to find \"%s\" MTD device: %ld\n", label, PTR_ERR(priv->mtd)); + 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->size; + + return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); +} + +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, + }, +}; + +static int __init u_boot_env_init(void) +{ + return platform_driver_register(&u_boot_env_driver); +} + +subsys_initcall_sync(u_boot_env_init); + +MODULE_AUTHOR("Rafał Miłecki"); +MODULE_LICENSE("GPL"); +MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);