Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754876AbdCGIb3 (ORCPT ); Tue, 7 Mar 2017 03:31:29 -0500 Received: from smtpfb2-g21.free.fr ([212.27.42.10]:58547 "EHLO smtpfb2-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754649AbdCGIbL (ORCPT ); Tue, 7 Mar 2017 03:31:11 -0500 From: Alban To: linux-kernel@vger.kernel.org Cc: Srinivas Kandagatla , Maxime Ripard , Rob Herring , Mark Rutland , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger , Cyrille Pitchen , devicetree@vger.kernel.org, linux-mtd@lists.infradead.org, Moritz Fischer , Alban Subject: [PATCH v2 2/2] mtd: Add support for reading MTD devices via the nvmem API Date: Tue, 7 Mar 2017 09:26:04 +0100 Message-Id: <1488875164-30440-3-git-send-email-albeu@free.fr> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488875164-30440-1-git-send-email-albeu@free.fr> References: <1488875164-30440-1-git-send-email-albeu@free.fr> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6263 Lines: 230 Allow drivers that use the nvmem API to read data stored on MTD devices. Add an option to the MTD core that allow registering the MTD as read-only NVMEM providers. Signed-off-by: Alban --- Changelog: v2: * Moved to the MTD core instead of using notifiers * Fixed the Kconfig description --- drivers/mtd/Kconfig | 9 +++++++ drivers/mtd/Makefile | 1 + drivers/mtd/mtdcore.c | 13 +++++++++ drivers/mtd/mtdnvmem.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++ drivers/mtd/mtdnvmem.h | 25 +++++++++++++++++ include/linux/mtd/mtd.h | 4 +++ 6 files changed, 124 insertions(+) create mode 100644 drivers/mtd/mtdnvmem.c create mode 100644 drivers/mtd/mtdnvmem.h diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig index e83a279..5a34c6a 100644 --- a/drivers/mtd/Kconfig +++ b/drivers/mtd/Kconfig @@ -322,6 +322,15 @@ config MTD_PARTITIONED_MASTER the parent of the partition device be the master device, rather than what lies behind the master. +config MTD_NVMEM + bool "Register MTD devices as NVMEM providers" + default y + depends on NVMEM || COMPILE_TEST + help + Provides support for reading config data from MTD devices. This can + be used by drivers to read device specific data such as MAC addresses + or calibration results. + source "drivers/mtd/chips/Kconfig" source "drivers/mtd/maps/Kconfig" diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile index 99bb9a1..879a542 100644 --- a/drivers/mtd/Makefile +++ b/drivers/mtd/Makefile @@ -5,6 +5,7 @@ # Core functionality. obj-$(CONFIG_MTD) += mtd.o mtd-y := mtdcore.o mtdsuper.o mtdconcat.o mtdpart.o mtdchar.o +mtd-$(CONFIG_MTD_NVMEM) += mtdnvmem.o obj-$(CONFIG_MTD_OF_PARTS) += ofpart.o obj-$(CONFIG_MTD_REDBOOT_PARTS) += redboot.o diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 66a9ded..bb88997 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -45,6 +45,7 @@ #include #include "mtdcore.h" +#include "mtdnvmem.h" static struct backing_dev_info *mtd_bdi; @@ -554,6 +555,11 @@ 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; + device_create(&mtd_class, mtd->dev.parent, MTD_DEVT(i) + 1, NULL, "mtd%dro", i); @@ -571,6 +577,8 @@ 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); @@ -611,6 +619,11 @@ int del_mtd_device(struct mtd_info *mtd) mtd->index, mtd->name, mtd->usecount); ret = -EBUSY; } else { + /* Try to remove the NVMEM provider */ + ret = mtd_nvmem_remove(mtd); + if (ret) + goto out_error; + device_unregister(&mtd->dev); idr_remove(&mtd_idr, mtd->index); diff --git a/drivers/mtd/mtdnvmem.c b/drivers/mtd/mtdnvmem.c new file mode 100644 index 0000000..d6bc402 --- /dev/null +++ b/drivers/mtd/mtdnvmem.c @@ -0,0 +1,72 @@ +/* + * Copyright (C) 2017 Alban Bedel + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include +#include +#include +#include + +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; +} + +int mtd_nvmem_add(struct mtd_info *mtd) +{ + struct device_node *np = dev_of_node(&mtd->dev); + struct nvmem_config config = {}; + + /* OF devices must have the nvmem-provider property */ + if (np && !of_property_read_bool(np, "nvmem-provider")) + return 0; + + config.dev = &mtd->dev; + 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.priv = mtd; + + mtd->nvmem = nvmem_register(&config); + if (IS_ERR(mtd->nvmem)) { + dev_err(&mtd->dev, "Failed to register NVMEM device\n"); + return PTR_ERR(mtd->nvmem); + } + + return 0; +} + +int mtd_nvmem_remove(struct mtd_info *mtd) +{ + int ret; + + if (!mtd->nvmem) + return 0; + + ret = nvmem_unregister(mtd->nvmem); + if (ret) + dev_err(&mtd->dev, "Failed to unregister NVMEM device\n"); + + return ret; +} + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Alban Bedel "); +MODULE_DESCRIPTION("Driver to read config data from MTD devices"); diff --git a/drivers/mtd/mtdnvmem.h b/drivers/mtd/mtdnvmem.h new file mode 100644 index 0000000..a49d8bd --- /dev/null +++ b/drivers/mtd/mtdnvmem.h @@ -0,0 +1,25 @@ +/* + * Copyright (C) 2017 Alban Bedel + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ +#ifndef MTD_NVMEM_H +#define MTD_NVMEM_H 1 + +struct mtd_info; + +#ifdef CONFIG_MTD_NVMEM +int mtd_nvmem_add(struct mtd_info *mtd); +int mtd_nvmem_remove(struct mtd_info *mtd); +#else +static inline int mtd_nvmem_add(struct mtd_info *mtd) +{ return 0; } + +static inline int mtd_nvmem_remove(struct mtd_info *mtd) +{ return 0; } +#endif + +#endif /* MTD_NVMEM_H */ diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index eebdc63..e06c6e6 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -205,6 +205,7 @@ struct mtd_pairing_scheme { }; struct module; /* only needed for owner field in mtd_info */ +struct nvmem_device; struct mtd_info { u_char type; @@ -351,6 +352,9 @@ struct mtd_info { struct module *owner; struct device dev; int usecount; +#if IS_ENABLED(CONFIG_MTD_NVMEM) + struct nvmem_device *nvmem; +#endif }; int mtd_ooblayout_ecc(struct mtd_info *mtd, int section, -- 2.7.4