Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752047AbdCBTx3 (ORCPT ); Thu, 2 Mar 2017 14:53:29 -0500 Received: from smtpfb1-g21.free.fr ([212.27.42.9]:49217 "EHLO smtpfb1-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751262AbdCBTxS (ORCPT ); Thu, 2 Mar 2017 14:53:18 -0500 From: Alban To: linux-kernel@vger.kernel.org Cc: devicetree@vger.kernel.org, linux-mtd@lists.infradead.org, Cyrille Pitchen , Richard Weinberger , Marek Vasut , Boris Brezillon , Brian Norris , David Woodhouse , Mark Rutland , Rob Herring , Maxime Ripard , Srinivas Kandagatla , Moritz Fischer , Alban Subject: [PATCH 2/3] mtd: Add support for reading MTD devices via the nvmem API Date: Thu, 2 Mar 2017 20:50:22 +0100 Message-Id: <1488484223-844-3-git-send-email-albeu@free.fr> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488484223-844-1-git-send-email-albeu@free.fr> References: <1488484223-844-1-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: 4668 Lines: 173 Allow drivers that use the nvmem API to read data stored on MTD devices. This add a simple mtd user that register itself as a read-only nvmem device. Signed-off-by: Alban --- drivers/mtd/Kconfig | 9 ++++ drivers/mtd/Makefile | 1 + drivers/mtd/mtdnvmem.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 131 insertions(+) create mode 100644 drivers/mtd/mtdnvmem.c diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig index e83a279..9cad86c 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 + tristate "Read config data from MTD devices" + default y + depends on NVMEM + 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..f62f50b 100644 --- a/drivers/mtd/Makefile +++ b/drivers/mtd/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_SSFDC) += ssfdc.o obj-$(CONFIG_SM_FTL) += sm_ftl.o obj-$(CONFIG_MTD_OOPS) += mtdoops.o obj-$(CONFIG_MTD_SWAP) += mtdswap.o +obj-$(CONFIG_MTD_NVMEM) += mtdnvmem.o nftl-objs := nftlcore.o nftlmount.o inftl-objs := inftlcore.o inftlmount.o diff --git a/drivers/mtd/mtdnvmem.c b/drivers/mtd/mtdnvmem.c new file mode 100644 index 0000000..6eb4216 --- /dev/null +++ b/drivers/mtd/mtdnvmem.c @@ -0,0 +1,121 @@ +/* + * 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 +#include +#include + +struct mtd_nvmem { + struct list_head list; + struct mtd_info *mtd; + struct nvmem_device *nvmem; +}; + +static DEFINE_MUTEX(mtd_nvmem_list_lock); +static LIST_HEAD(mtd_nvmem_list); + +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 void mtd_nvmem_add(struct mtd_info *mtd) +{ + struct device *dev = &mtd->dev; + struct device_node *np = dev_of_node(dev); + struct nvmem_config config = {}; + struct mtd_nvmem *mtd_nvmem; + + /* OF devices have to provide the nvmem node */ + if (np && !of_property_read_bool(np, "nvmem-provider")) + return; + + config.dev = 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; + + /* Alloc our struct to keep track of the MTD NVMEM devices */ + mtd_nvmem = kzalloc(sizeof(*mtd_nvmem), GFP_KERNEL); + if (!mtd_nvmem) + return; + + mtd_nvmem->mtd = mtd; + mtd_nvmem->nvmem = nvmem_register(&config); + if (IS_ERR(mtd_nvmem->nvmem)) { + dev_err(dev, "Failed to register NVMEM device\n"); + kfree(mtd_nvmem); + return; + } + + mutex_lock(&mtd_nvmem_list_lock); + list_add_tail(&mtd_nvmem->list, &mtd_nvmem_list); + mutex_unlock(&mtd_nvmem_list_lock); +} + +static void mtd_nvmem_remove(struct mtd_info *mtd) +{ + struct mtd_nvmem *mtd_nvmem; + bool found = false; + + mutex_lock(&mtd_nvmem_list_lock); + list_for_each_entry(mtd_nvmem, &mtd_nvmem_list, list) { + if (mtd_nvmem->mtd == mtd) { + list_del(&mtd_nvmem->list); + found = true; + break; + } + } + mutex_unlock(&mtd_nvmem_list_lock); + + if (found) { + if (nvmem_unregister(mtd_nvmem->nvmem)) + dev_err(&mtd->dev, + "Failed to unregister NVMEM device\n"); + kfree(mtd_nvmem); + } +} + +static struct mtd_notifier mtd_nvmem_notifier = { + .add = mtd_nvmem_add, + .remove = mtd_nvmem_remove, +}; + +static int __init mtd_nvmem_init(void) +{ + register_mtd_user(&mtd_nvmem_notifier); + return 0; +} +module_init(mtd_nvmem_init); + +static void __exit mtd_nvmem_exit(void) +{ + unregister_mtd_user(&mtd_nvmem_notifier); +} +module_exit(mtd_nvmem_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Alban Bedel "); +MODULE_DESCRIPTION("Driver to read config data from MTD devices"); -- 2.7.4