From patchwork Wed Jun 15 19:42:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= X-Patchwork-Id: 12882863 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 719C9C43334 for ; Wed, 15 Jun 2022 19:44:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=ornlj+lQIl1ShyAyTKdbBXkdIqnyoNdQrrCdanE/SPg=; b=RRYvbWWvw/TN20 MXzsWybhBvocat/GfqtSvhvzSnKenNYNYdPGdbTyq5H68SPzw+KmnJ/ONMs2rfqBuNuWvnvxCjMnN HNgxmbP4q+/Mism7/dXA0AdW//LfwOeCGtO2lFYFVRVVwelK07y1TY2UdceS4aMCoZ8eWgXjn+NCQ bLuCRe0Ib3KjBUBz9xxSqb88cu75oWVuqBYXJ5EhDr/leTrgz41OqY2sWM5EBibeeLeEwkiDMD7Tg 4JLKizUT1798mLj/pAJw/KLgc6cKjrRw/qkR/PpYOsjvnx8Li1ny3mhKFG9L65N+yoiWDyG5bC3/I JeKejMue1pHscLuc1dNQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o1Yv6-00G6fG-8F; Wed, 15 Jun 2022 19:43:16 +0000 Received: from mail-ej1-x630.google.com ([2a00:1450:4864:20::630]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o1Yv3-00G6e7-Ia; Wed, 15 Jun 2022 19:43:14 +0000 Received: by mail-ej1-x630.google.com with SMTP id g25so25237244ejh.9; Wed, 15 Jun 2022 12:43:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=NeAaQxHNgpvGGApabF2dZ5cx3n1PATnxM0M/iIuIjaA=; b=k14tMQCVOVeOrgEvHimQMUqpKcCa52Ahn9gpZ0rCs6UBPmduwGS/RyEeSxGl32iBsa 6sdJ2TwTf6gszE58GZjCVQJGrDA8gpYriykjwER+3ZPpzBx0LofuIzLo3P27yLoq7fgW 7Rt6xQ+cd9bin8kCAxVf9OAmEkf0xoPvJLzAq1UnhUnZXXHDizAgllKcQfoCJgc78lH8 f21xjPvnjHZJTTHcF5sfaryaMZuoSMBC9rM7poPFB2MPk1aJEBojUV7SB2CYo3Di4L+B +NVJ/3Qlpw2Fql50DHr+uEEqIoYmTRaMWDB+tUmgCak9rIhAlxwXqizC2JzH6fYVEb/l H8aQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=NeAaQxHNgpvGGApabF2dZ5cx3n1PATnxM0M/iIuIjaA=; b=hjjgeypoLv5nAGKAGUbZ8V0HOZC4RLTbVAib96QEraTvYaXL1xeY7LKrvYLq2NcN0D L83jiET3d4FhfhMbrlEIdoMoLMW30MroKp5i1ymot8Q/1eyGaZPSGjZ93Q+ZUUw6Kluz GTXTZ6g5+W0m+CnP03Tzgl9M6rpbEjoqUD1xnqGJRWAm28jif5z/Tf+RFhUhctqeOrCe EXoH9sCf7w8EE09JVjLFeqvSnrx07E75VZPj08Ssaf2h4ulMBoW3KF5c9FMFCEllT/rd VfnWhCUMWkpJ+GKzNAW1D6NDwDWZWqIjky9f4Po0sILigtEzxXB5smZnCqZMKU2LCm2y Q4YQ== X-Gm-Message-State: AJIora8g5cL+DAYc+oOtV4MHDBXCBqOAqc2Fq8YUm782Ep8aA7D7b1iW CampsbQ8IZl2t1/uzG0lOXw= X-Google-Smtp-Source: AGRyM1sAO6s8WrkND9IqSLFNkOoSsbBsyq8tmeli3+/6WTSIMEkds8HRFI63vvFEhffvyAQFIfxN2g== X-Received: by 2002:a17:906:9244:b0:70c:f626:944d with SMTP id c4-20020a170906924400b0070cf626944dmr1300802ejx.496.1655322191129; Wed, 15 Jun 2022 12:43:11 -0700 (PDT) Received: from localhost.lan (ip-194-187-74-233.konfederacka.maverick.com.pl. [194.187.74.233]) by smtp.gmail.com with ESMTPSA id a16-20020aa7d750000000b0042bd6f745fasm18096eds.92.2022.06.15.12.43.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jun 2022 12:43:10 -0700 (PDT) From: =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= To: Srinivas Kandagatla , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra Cc: Tom Rini , Ahmad Fatoum , linux-arm-kernel@lists.infradead.org, u-boot@lists.denx.de, devicetree@vger.kernel.org, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= Subject: [PATCH V4 1/2] mtd: allow getting MTD device associated with a specific DT node Date: Wed, 15 Jun 2022 21:42:59 +0200 Message-Id: <20220615194300.13358-1-zajec5@gmail.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220615_124313_660514_64CF3D2A X-CRM114-Status: GOOD ( 13.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Rafał Miłecki MTD subsystem API allows interacting with MTD devices (e.g. reading, writing, handling bad blocks). So far a random driver could get MTD device only by its name (get_mtd_device_nm()). This change allows getting them also by a DT node. This API is required for drivers handling DT defined MTD partitions in a specific way (e.g. U-Boot (sub)partition with environment variables). Signed-off-by: Rafał Miłecki Acked-by: Miquel Raynal Reviewed-by: Ahmad Fatoum --- V3: First introduction of of_get_mtd_device_by_node() V4: Use EPROBE_DEFER Srinivas: in V3 Miquel said it's OK to push this patch through NVMEM --- drivers/mtd/mtdcore.c | 28 ++++++++++++++++++++++++++++ include/linux/mtd/mtd.h | 1 + 2 files changed, 29 insertions(+) diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 9eb0680db312..3613cc142f25 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -1154,6 +1154,34 @@ int __get_mtd_device(struct mtd_info *mtd) } EXPORT_SYMBOL_GPL(__get_mtd_device); +/** + * of_get_mtd_device_by_node - obtain an MTD device associated with a given node + * + * @np: device tree node + */ +struct mtd_info *of_get_mtd_device_by_node(struct device_node *np) +{ + struct mtd_info *mtd = NULL; + struct mtd_info *tmp; + int err; + + mutex_lock(&mtd_table_mutex); + + err = -EPROBE_DEFER; + mtd_for_each_device(tmp) { + if (mtd_get_of_node(tmp) == np) { + mtd = tmp; + err = __get_mtd_device(mtd); + break; + } + } + + mutex_unlock(&mtd_table_mutex); + + return err ? ERR_PTR(err) : mtd; +} +EXPORT_SYMBOL_GPL(of_get_mtd_device_by_node); + /** * get_mtd_device_nm - obtain a validated handle for an MTD device by * device name diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index 955aee14b0f7..6fc841ceef31 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -677,6 +677,7 @@ extern int mtd_device_unregister(struct mtd_info *master); extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num); extern int __get_mtd_device(struct mtd_info *mtd); extern void __put_mtd_device(struct mtd_info *mtd); +extern struct mtd_info *of_get_mtd_device_by_node(struct device_node *np); extern struct mtd_info *get_mtd_device_nm(const char *name); extern void put_mtd_device(struct mtd_info *mtd); From patchwork Wed Jun 15 19:43:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= X-Patchwork-Id: 12882864 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 25CD4CCA473 for ; Wed, 15 Jun 2022 19:44:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WncuODw2Nlt1JbkMRO3lvTu6l9ftFwBjy5t2wEIAE1U=; b=JHz0Xn6sVuq+IM JCJiNNtTBwfxsmy+BNUWknLfJA8zp5yfDNrsZfnAQKa9NR/rkIumrBHbWePzpDsS8oTYmGo7to0ht xcaSSuH5NAtjsTNdJLHg4naOXMFOMuhSg84N/YpelckGrObNbhdc6K8ZzhPmYSTlvha3uXpCDB7eR pZgnzkb/doam5VR4p1uCK28/3MGWhAqa3iIKifmFl1YZHTreDG8cWQ3nvnlB5fLOZwR6rjjHpCb0w q8qnaiXaYJMtR+isCwmYjztjpqNh9I+Uf0prgbvK/+srQaYz7AbAVERP3zNKpgr/ckztjluzeLKPU HHT1eYtNumVeV4fD4lZg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o1YvG-00G6j1-LR; Wed, 15 Jun 2022 19:43:26 +0000 Received: from mail-ej1-x62d.google.com ([2a00:1450:4864:20::62d]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o1Yv5-00G6eF-3n; Wed, 15 Jun 2022 19:43:17 +0000 Received: by mail-ej1-x62d.google.com with SMTP id m20so25201848ejj.10; Wed, 15 Jun 2022 12:43:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=WJt5W0EU+sFGaIOZbZ00omdFEDMKZn+VKOgfz5mNEys=; b=b6ysLzlmtRDwylwJm+veQg5s5/vYYErEooJ/Za89I9oViMbUzDMhBbTkShsSQheCLT Ze1sBG5WIQkFwVMq6NgJ9BGXQdNcbFyl74LC5B2CYlPuAje9SLLZB68Um551EM2RMPf/ Budgdhvy4B+A/OxGLMsVQudyDpCj4T93lsk36tK3MCawYkmCLvOEAIX6ocrMQtxu4niR naWZdckq5bJeboip25/FUNax9JBIQ2MgCNOqZs9fOG81GPolMPMTF3Y97P9rKNFQL6j/ eH2OEfNVSW84FcB8cCuqjF471WIPYOPZsM+41Z9m63xpcjmKNXGiyzMOxeCDpOVGV4Xs MjGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=WJt5W0EU+sFGaIOZbZ00omdFEDMKZn+VKOgfz5mNEys=; b=J1nXrNqAMdi4cbaUIiJxaWb4rKs8NQXBmg63iHTRmw08KVZVgi4NQB44hqjQI3c9Nv jpNBJmUMJtOE4a+zjKUQM7Omz8htAB55Ic6fQgfp8V842JI1/q4cwN1cHnq2Z4m5/+tq 30+z5EseqBENF/3WtJOEtZQTlBqKqMrre/aB/n9ZFQaQhGcdh0vopIa5Rn4df8yJEIZk 6lEoSaKvrgWswwwSmsTQAXMMLCiXFnbrCfrAjJ3mSfrA9Fw3vP8po7LbKBVz1eu4ZDGZ bMPK6yPvIBUPjoiMhYk9EfQrlYeT5ZRJjhJDUPpQpJps2HIZI1clIUkM4KMCEGxtj2EG LLwQ== X-Gm-Message-State: AJIora+JlCeSuo9OVVo4ez6FLG9DHvPLOXB50Hz5rILshfuA8rbK/BSS k+URve8xIJJOkVJ7RsbM4o8= X-Google-Smtp-Source: AGRyM1vuPw3OzAl1eoIW9BvwLnSyUlDJiu+Q9utQNlOZQIXLMbxiEkM/zTeNKNlSxeQt4nmVcpW2/A== X-Received: by 2002:a17:906:649b:b0:712:24cd:6102 with SMTP id e27-20020a170906649b00b0071224cd6102mr1320880ejm.664.1655322193217; Wed, 15 Jun 2022 12:43:13 -0700 (PDT) Received: from localhost.lan (ip-194-187-74-233.konfederacka.maverick.com.pl. [194.187.74.233]) by smtp.gmail.com with ESMTPSA id a16-20020aa7d750000000b0042bd6f745fasm18096eds.92.2022.06.15.12.43.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jun 2022 12:43:12 -0700 (PDT) From: =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= To: Srinivas Kandagatla , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra Cc: Tom Rini , Ahmad Fatoum , linux-arm-kernel@lists.infradead.org, u-boot@lists.denx.de, devicetree@vger.kernel.org, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= Subject: [PATCH V4 2/2] nvmem: add driver handling U-Boot environment variables Date: Wed, 15 Jun 2022 21:43:00 +0200 Message-Id: <20220615194300.13358-2-zajec5@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220615194300.13358-1-zajec5@gmail.com> References: <20220615194300.13358-1-zajec5@gmail.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220615_124315_208619_942DF774 X-CRM114-Status: GOOD ( 30.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Rafał Miłecki 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 --- V3: Use of_get_mtd_device_by_node() (thanks Ahmad) & update description V2: Drop ARCH_BCM4908 dependency as there are plenty architectures using U-Boot bootloader. Thanks Srinivas. V4: Mention MTD in Kconfig help Use correct MTD device (instead of parent) - simplifies code a lot Use flexible arrays syntax ([]) Use of_device_get_match_data() helper Use dev_err_probe() As noticed by Ahmad a missing NVMEM subsystem feature is user-space access to parsed NVMEM cells. That is something I started working on some time ago and I'm planning to get back to at some point, please check: [PATCH 2/2] nvmem: expose NVMEM cells in sysfs https://lore.kernel.org/lkml/20211220064730.28806-2-zajec5@gmail.com/ --- MAINTAINERS | 1 + drivers/nvmem/Kconfig | 13 +++ drivers/nvmem/Makefile | 2 + drivers/nvmem/u-boot-env.c | 218 +++++++++++++++++++++++++++++++++++++ 4 files changed, 234 insertions(+) create mode 100644 drivers/nvmem/u-boot-env.c diff --git a/MAINTAINERS b/MAINTAINERS index 475e28365385..43b427fa76b0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20411,6 +20411,7 @@ 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 d72d879a6d34..bab8a29c9861 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -344,4 +344,17 @@ config NVMEM_APPLE_EFUSES This driver can also be built as a module. If so, the module will be called nvmem-apple-efuses. +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 diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index c710b64f9fe4..399f9972d45b 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -69,3 +69,5 @@ obj-$(CONFIG_NVMEM_APPLE_EFUSES) += nvmem-apple-efuses.o nvmem-apple-efuses-y := apple-efuses.o obj-$(CONFIG_MICROCHIP_OTPC) += nvmem-microchip-otpc.o nvmem-microchip-otpc-y := microchip-otpc.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..9b9abfb8f187 --- /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 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +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);