From patchwork Tue Nov 13 14:01:10 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bartosz Golaszewski X-Patchwork-Id: 997184 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=bgdev.pl Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=bgdev-pl.20150623.gappssmtp.com header.i=@bgdev-pl.20150623.gappssmtp.com header.b="1ikfHGcP"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 42vTtD56hjz9rxp for ; Wed, 14 Nov 2018 01:05:40 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387533AbeKNAAP (ORCPT ); Tue, 13 Nov 2018 19:00:15 -0500 Received: from mail-wr1-f65.google.com ([209.85.221.65]:35690 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387564AbeKNAAO (ORCPT ); Tue, 13 Nov 2018 19:00:14 -0500 Received: by mail-wr1-f65.google.com with SMTP id z16-v6so13460830wrv.2 for ; Tue, 13 Nov 2018 06:01:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ksw4hZ+0N23CBRzViPcOA1hnkMZq7TwewkS2aWR80tA=; b=1ikfHGcPDC7civleiORZ2R6ytLyQkE+DF3bz38/TlgOGb4db6Pb5oyhZCqXDaGbq9u DMPdIAFqsnfD+HrHgIQRcFmJaUKvccb3hcn6kXpyiVb5WWDx8MKiSsTIKNeBAqS12BmK WTGRTHXYdtkpZ4bXgwIK9/EQ06exjzKtDLzIv0x9ygty09EtOkezSa7WPzHm/dtfUVc0 3TM292Mj0wUaEsBOyUFj3K1IrRLUtm6dISO4RJGy7DiDHtY+lmfEZpEdrXRWQq/44uqt jGXp6oIku4gvdtFVjyTgRR7z9WmtcqiX44GF0l5Msezrhrptp4uLgVx/09rGO1tOlIai c0QA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ksw4hZ+0N23CBRzViPcOA1hnkMZq7TwewkS2aWR80tA=; b=oYrE2UwepsIhNPPit01NpCk/FAT2sxEavUjCRqV7W4HOs3EK2+6tS/Mq+lMTkMKNLd GeWWTES11FRyvLVGw9g2D6Rg0G0hg/6Yj4rPQz4AiBHPGCVrbELpW7YbTf8GK7mypd7I M5wK8C0T2mmq7lZNchecqw3C2/PewbzzXaYxbIS7PnIyH5kM18VXDjsZm3ONE+PP1eE7 VH61VP1h1NaRNUYlQbbVQ2UXL57LedMvY1nIolBWSPxsJeAkV4O4PtuS8GuSImLIRaJf SaHolDc54UgRtlUMAC5Gt+qJ3KbT0J11cvD4YvZYejPz93nRxIWG3P0lsZaAfMsV/Juh aEpQ== X-Gm-Message-State: AGRZ1gJ7npeB+VVKiAfg5/7Glg42oLS3iUfBM2fxXF3IrvIWbmaKy8my RD9dJK+wp/oYuJAlxI8bk7q+9A== X-Google-Smtp-Source: AJdET5ckp3K70W7StwZJeboEAtFKzDmx/OnuA1iLeoinTgd75JyxZfX9FHcefhNMMtZoneFrPyq7Mg== X-Received: by 2002:adf:eb0b:: with SMTP id s11-v6mr5036642wrn.102.1542117716930; Tue, 13 Nov 2018 06:01:56 -0800 (PST) Received: from debian-brgl.home ([2a01:cb1d:af:5b00:6d6c:8493:1ab5:dad7]) by smtp.gmail.com with ESMTPSA id m69-v6sm16604122wmb.8.2018.11.13.06.01.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 13 Nov 2018 06:01:56 -0800 (PST) From: Bartosz Golaszewski To: Sekhar Nori , Kevin Hilman , Russell King , Arnd Bergmann , Greg Kroah-Hartman , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger , Nicolas Ferre , "David S . Miller" , Grygorii Strashko , Srinivas Kandagatla , Andrew Lunn , Florian Fainelli , Rob Herring , Frank Rowand , Wolfram Sang Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, linux-mtd@lists.infradead.org, netdev@vger.kernel.org, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, Alban Bedel , Bartosz Golaszewski Subject: [PATCH v2 02/25] mtd: add support for reading MTD devices via the nvmem API Date: Tue, 13 Nov 2018 15:01:10 +0100 Message-Id: <20181113140133.17385-3-brgl@bgdev.pl> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181113140133.17385-1-brgl@bgdev.pl> References: <20181113140133.17385-1-brgl@bgdev.pl> MIME-Version: 1.0 Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Alban Bedel Allow drivers that use the nvmem API to read data stored on MTD devices. For this the mtd devices are registered as read-only NVMEM providers. We don't support device tree systems for now. Signed-off-by: Alban Bedel [Bartosz: - include linux/nvmem-provider.h - set the name of the nvmem provider - set no_of_node to true in nvmem_config - don't check the return value of nvmem_unregister() - it cannot fail - tweaked the commit message] Signed-off-by: Bartosz Golaszewski Acked-by: Boris Brezillon --- drivers/mtd/Kconfig | 1 + drivers/mtd/mtdcore.c | 56 +++++++++++++++++++++++++++++++++++++++++ include/linux/mtd/mtd.h | 2 ++ 3 files changed, 59 insertions(+) diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig index c77f537323ec..efbe7a6f1d8f 100644 --- a/drivers/mtd/Kconfig +++ b/drivers/mtd/Kconfig @@ -1,5 +1,6 @@ menuconfig MTD tristate "Memory Technology Device (MTD) support" + imply NVMEM help Memory Technology Devices are flash, RAM and similar chips, often used for solid state file systems on embedded devices. This option diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 97ac219c082e..5f1053d995b0 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include @@ -488,6 +489,50 @@ int mtd_pairing_groups(struct mtd_info *mtd) } EXPORT_SYMBOL_GPL(mtd_pairing_groups); +static int mtd_nvmem_reg_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct mtd_info *mtd = priv; + size_t retlen; + int err; + + err = mtd_read(mtd, offset, bytes, &retlen, val); + if (err && err != -EUCLEAN) + return err; + + return retlen == bytes ? 0 : -EIO; +} + +static int mtd_nvmem_add(struct mtd_info *mtd) +{ + struct nvmem_config config = {}; + + config.dev = &mtd->dev; + config.name = mtd->name; + config.owner = THIS_MODULE; + config.reg_read = mtd_nvmem_reg_read; + config.size = mtd->size; + config.word_size = 1; + config.stride = 1; + config.read_only = true; + config.root_only = true; + config.no_of_node = true; + config.priv = mtd; + + mtd->nvmem = nvmem_register(&config); + if (IS_ERR(mtd->nvmem)) { + /* Just ignore if there is no NVMEM support in the kernel */ + if (PTR_ERR(mtd->nvmem) == -ENOSYS) { + mtd->nvmem = NULL; + } else { + dev_err(&mtd->dev, "Failed to register NVMEM device\n"); + return PTR_ERR(mtd->nvmem); + } + } + + return 0; +} + static struct dentry *dfs_dir_mtd; /** @@ -570,6 +615,11 @@ int add_mtd_device(struct mtd_info *mtd) if (error) goto fail_added; + /* Add the nvmem provider */ + error = mtd_nvmem_add(mtd); + if (error) + goto fail_nvmem_add; + if (!IS_ERR_OR_NULL(dfs_dir_mtd)) { mtd->dbg.dfs_dir = debugfs_create_dir(dev_name(&mtd->dev), dfs_dir_mtd); if (IS_ERR_OR_NULL(mtd->dbg.dfs_dir)) { @@ -595,6 +645,8 @@ int add_mtd_device(struct mtd_info *mtd) __module_get(THIS_MODULE); return 0; +fail_nvmem_add: + device_unregister(&mtd->dev); fail_added: of_node_put(mtd_get_of_node(mtd)); idr_remove(&mtd_idr, i); @@ -637,6 +689,10 @@ int del_mtd_device(struct mtd_info *mtd) mtd->index, mtd->name, mtd->usecount); ret = -EBUSY; } else { + /* Try to remove the NVMEM provider */ + if (mtd->nvmem) + nvmem_unregister(mtd->nvmem); + device_unregister(&mtd->dev); idr_remove(&mtd_idr, mtd->index); diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index cd0be91bdefa..545070c2ee64 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -25,6 +25,7 @@ #include #include #include +#include #include @@ -341,6 +342,7 @@ struct mtd_info { struct device dev; int usecount; struct mtd_debug_info dbg; + struct nvmem_device *nvmem; }; int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,