From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A8F21C433E4 for ; Mon, 22 Mar 2021 18:21:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7DFDF61998 for ; Mon, 22 Mar 2021 18:21:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231961AbhCVSUv (ORCPT ); Mon, 22 Mar 2021 14:20:51 -0400 Received: from ssl.serverraum.org ([176.9.125.105]:43897 "EHLO ssl.serverraum.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231462AbhCVSUO (ORCPT ); Mon, 22 Mar 2021 14:20:14 -0400 Received: from mwalle01.fritz.box (unknown [IPv6:2a02:810c:c200:2e91:fa59:71ff:fe9b:b851]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id 58DF322255; Mon, 22 Mar 2021 19:20:10 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1616437210; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9KjLV5Ka9bey5dKJWPzgAenJL/VH5mtWkQstrGXp430=; b=G3z7uufUUt2D4bHIAoA4KFcAr3mhdhx0PHU/l3H/v7it49QhCW3A5oNbPGULPE3Xn0vPOl D1l926b4w4CZVGDh/qOyWXc3pSs6d3t0QBYW+fXaOOmpxIQV/HOe7RNT9AiGwor5oBwNXs G5l1ZAha5g177tWwp/hPEtQdJobYqfg= From: Michael Walle To: linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Rob Herring , Srinivas Kandagatla , =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= , Michael Walle Subject: [RFC PATCH 4/4] mtd: core: add OTP nvmem provider support Date: Mon, 22 Mar 2021 19:19:49 +0100 Message-Id: <20210322181949.2805-5-michael@walle.cc> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210322181949.2805-1-michael@walle.cc> References: <20210322181949.2805-1-michael@walle.cc> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Flash OTP regions can already be read via user space. Some boards have their serial number or MAC addresses stored in the OTP regions. Add support for them being a (read-only) nvmem provider. The API to read the OTP data is already in place. It distinguishes between factory and user OTP, thus there are up to two different providers. Signed-off-by: Michael Walle --- drivers/mtd/mtdcore.c | 149 ++++++++++++++++++++++++++++++++++++++++ include/linux/mtd/mtd.h | 2 + 2 files changed, 151 insertions(+) diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 432769caae04..300340973561 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -776,6 +776,147 @@ static void mtd_set_dev_defaults(struct mtd_info *mtd) mutex_init(&mtd->master.chrdev_lock); } +static ssize_t mtd_otp_size(struct mtd_info *mtd, bool is_user) +{ + struct otp_info *info = kmalloc(PAGE_SIZE, GFP_KERNEL); + ssize_t size = 0; + unsigned int i; + size_t retlen; + int ret; + + if (is_user) + ret = mtd_get_user_prot_info(mtd, PAGE_SIZE, &retlen, info); + else + ret = mtd_get_fact_prot_info(mtd, PAGE_SIZE, &retlen, info); + if (ret) + goto err; + + for (i = 0; i < retlen / sizeof(*info); i++) { + size += info->length; + info++; + } + + kfree(info); + return size; + +err: + kfree(info); + return ret; +} + +static struct nvmem_device *mtd_otp_nvmem_register(struct mtd_info *mtd, + const char *name, int size, + nvmem_reg_read_t reg_read, + const char *compatible) +{ + struct nvmem_device *nvmem = NULL; + struct nvmem_config config = {}; + struct device_node *np; + + /* DT binding is optional */ + np = of_get_compatible_child(mtd->dev.of_node, compatible); + + /* OTP nvmem will be registered on the physical device */ + config.dev = mtd->dev.parent; + config.name = name; + config.id = NVMEM_DEVID_NONE; + config.owner = THIS_MODULE; + config.type = NVMEM_TYPE_OTP; + config.root_only = true; + config.reg_read = reg_read; + config.size = size; + config.of_node = np; + config.priv = mtd; + + nvmem = nvmem_register(&config); + /* Just ignore if there is no NVMEM support in the kernel */ + if (IS_ERR(nvmem) && PTR_ERR(nvmem) == -EOPNOTSUPP) + nvmem = NULL; + + of_node_put(np); + + return nvmem; +} + +static int mtd_nvmem_user_otp_reg_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct mtd_info *mtd = priv; + size_t retlen; + int ret; + + ret = mtd_read_user_prot_reg(mtd, offset, bytes, &retlen, val); + if (ret) + return ret; + + return retlen == bytes ? 0 : -EIO; +} + +static int mtd_nvmem_fact_otp_reg_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct mtd_info *mtd = priv; + size_t retlen; + int ret; + + ret = mtd_read_fact_prot_reg(mtd, offset, bytes, &retlen, val); + if (ret) + return ret; + + return retlen == bytes ? 0 : -EIO; +} + +static int mtd_otp_nvmem_add(struct mtd_info *mtd) +{ + struct nvmem_device *nvmem; + ssize_t size; + int err; + + if (mtd->_get_user_prot_info && mtd->_read_user_prot_reg) { + size = mtd_otp_size(mtd, true); + if (size < 0) + return size; + + if (size > 0) { + nvmem = mtd_otp_nvmem_register(mtd, "user-otp", size, + mtd_nvmem_user_otp_reg_read, + "mtd-user-otp"); + if (IS_ERR(nvmem)) { + dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n"); + return PTR_ERR(nvmem); + } + mtd->otp_user_nvmem = nvmem; + } + } + + if (mtd->_get_fact_prot_info && mtd->_read_fact_prot_reg) { + size = mtd_otp_size(mtd, false); + if (size < 0) { + err = size; + goto err; + } + + if (size > 0) { + nvmem = mtd_otp_nvmem_register(mtd, "factory-otp", size, + mtd_nvmem_fact_otp_reg_read, + "mtd-factory-otp"); + if (IS_ERR(nvmem)) { + dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n"); + err = PTR_ERR(nvmem); + goto err; + } + mtd->otp_factory_nvmem = nvmem; + } + } + + return 0; + +err: + if (mtd->otp_user_nvmem) + nvmem_unregister(mtd->otp_user_nvmem); + return err; +} + /** * mtd_device_parse_register - parse partitions and register an MTD device. * @@ -851,6 +992,8 @@ int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types, register_reboot_notifier(&mtd->reboot_notifier); } + ret = mtd_otp_nvmem_add(mtd); + out: if (ret && device_is_registered(&mtd->dev)) del_mtd_device(mtd); @@ -872,6 +1015,12 @@ int mtd_device_unregister(struct mtd_info *master) if (master->_reboot) unregister_reboot_notifier(&master->reboot_notifier); + if (master->otp_user_nvmem) + nvmem_unregister(master->otp_user_nvmem); + + if (master->otp_factory_nvmem) + nvmem_unregister(master->otp_factory_nvmem); + err = del_mtd_partitions(master); if (err) return err; diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index 4aac200ca8b5..71e751d18c22 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -379,6 +379,8 @@ struct mtd_info { int usecount; struct mtd_debug_info dbg; struct nvmem_device *nvmem; + struct nvmem_device *otp_user_nvmem; + struct nvmem_device *otp_factory_nvmem; /* * Parent device from the MTD partition point of view. -- 2.20.1