From patchwork Thu Sep 1 22:18:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Walle X-Patchwork-Id: 12963391 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 21422C54EE9 for ; Thu, 1 Sep 2022 22:23:19 +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=LkxRbfKkcKNFU1fWZZUHVzCFUw0Krql33TxnuQZqw4s=; b=b8d7tw7f/zM8Jl MmZrpwT9y6eZb/CGKpXoahYf8E/FqGLcm4KxNZdeZt54BPxnWmHfnySGH51Nv/XJYF8omnxozej5k XVf8tjXi07OqlGTN+LVEvdVPBHRXi7GP1g200wXZXYpdoG4GcqmVWHTiw+bjAWhT5uNIXnZqPKY8W D+EE8sKasU9MKMCSCkLkMMsxeWQPs+ZkRf7j804MU4YskCPgcTJj7dNlIRr3+03KyUiBru5EAVinN kVx5DNQkgBHJHNWVI/cEQifDLdPE1QeeJif33KjtjHEBRWpzZcDZiX8ZPccXnhI1REc84KDUnQwKy AH84aydJGWYH2oHUs2lA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oTsZd-00FH0C-1v; Thu, 01 Sep 2022 22:22:09 +0000 Received: from 0001.3ffe.de ([159.69.201.130] helo=mail.3ffe.de) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oTsWt-00FEdb-UC; Thu, 01 Sep 2022 22:19:23 +0000 Received: from mwalle01.kontron.local. (unknown [213.135.10.150]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mail.3ffe.de (Postfix) with ESMTPSA id D8BD221D8; Fri, 2 Sep 2022 00:19:11 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2022082101; t=1662070752; 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=MB/t+1HQcFJ8w0iMCkQzsjPb6YGMRkeITQOlS7zSzWI=; b=Hm9VEphIqRqtwHvY5u5z0jS28RcIVe5sMXYmcskpH2DgDJgUCPjKXQDX8fFEGBY4XkDFNZ T6caA6j6r5aBV7fUcoyUX1GW8IuG4YnowxGxmIBAhpY9YW3gmjt92P1Xr8mOr2mB03pOCb bOWkxJQZuM16TuUC9A1H5hOMqj0FjdPeDTssjXbAsUJbh/PDHTFzZhhGO8Oz2wPppj8oxD pdFhjVCA/yI4FFf0FFgpUAfKFddayicSHEiZ4Bjbg6Rg0yiFwAsye6hXpTwBRJFhmRRNoj vmpiPM11lqo/g4SWypmj+mGog8VK541TJqgQgWCGpgAEkv01IO8xsm957YmlxQ== From: Michael Walle To: Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Rob Herring , Krzysztof Kozlowski , Srinivas Kandagatla , Shawn Guo , Li Yang , =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= , Frank Rowand Cc: linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Ahmad Fatoum , Philipp Zabel , Michael Walle Subject: [PATCH v2 08/20] nvmem: core: introduce NVMEM layouts Date: Fri, 2 Sep 2022 00:18:45 +0200 Message-Id: <20220901221857.2600340-9-michael@walle.cc> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220901221857.2600340-1-michael@walle.cc> References: <20220901221857.2600340-1-michael@walle.cc> MIME-Version: 1.0 X-Spam: Yes X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220901_151920_179766_ECD6CE47 X-CRM114-Status: GOOD ( 35.03 ) 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 NVMEM layouts are used to generate NVMEM cells during runtime. Think of an EEPROM with a well-defined conent. For now, the content can be described by a device tree or a board file. But this only works if the offsets and lengths are static and don't change. One could also argue that putting the layout of the EEPROM in the device tree is the wrong place. Instead, the device tree should just have a specific compatible string. Right now there are two use cases: (1) The NVMEM cell needs special processing. E.g. if it only specifies a base MAC address offset and you need to add an offset, or it needs to parse a MAC from ASCII format or some proprietary format. (Post processing of cells is added in a later commit). (2) u-boot environment parsing. The cells don't have a particular offset but it needs parsing the content to determine the offsets and length. Signed-off-by: Michael Walle --- changes since v1: - add documentation in nvmem.rst - add nvmem_layout_unregister() + necessary module tracking - make it possible to supply a layout via nvmem_register() - check add_cells, before calling Documentation/driver-api/nvmem.rst | 15 ++++++ drivers/nvmem/Kconfig | 4 ++ drivers/nvmem/Makefile | 1 + drivers/nvmem/core.c | 85 ++++++++++++++++++++++++++++++ drivers/nvmem/layouts/Kconfig | 5 ++ drivers/nvmem/layouts/Makefile | 4 ++ include/linux/nvmem-provider.h | 51 ++++++++++++++++++ 7 files changed, 165 insertions(+) create mode 100644 drivers/nvmem/layouts/Kconfig create mode 100644 drivers/nvmem/layouts/Makefile diff --git a/Documentation/driver-api/nvmem.rst b/Documentation/driver-api/nvmem.rst index e3366322d46c..de221e91c8e3 100644 --- a/Documentation/driver-api/nvmem.rst +++ b/Documentation/driver-api/nvmem.rst @@ -185,3 +185,18 @@ ex:: ===================== See Documentation/devicetree/bindings/nvmem/nvmem.txt + +8. NVMEM layouts +================ + +NVMEM layouts are yet another mechanism to create cells. With the device +tree binding it is possible to specify simple cells by using an offset +and a length. Sometimes, the cells doesn't have a static offset, but +the content is still well defined, e.g. tag-length-values. In this case, +the NVMEM device content has to be first parsed and the cells need to +be added accordingly. Layouts let you read the content of the NVMEM device +and let you add cells dynamically. + +Another use case for layouts is the post processing of cells. With layouts, +it is possible to associate a custom post processing hook to a cell. It +even possible to add this hook to cells not created by the layout itself. diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index 7f2557934834..adacb113cb94 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -21,6 +21,10 @@ config NVMEM_SYSFS This interface is mostly used by userspace applications to read/write directly into nvmem. +# Layouts + +source "drivers/nvmem/layouts/Kconfig" + # Devices config NVMEM_APPLE_EFUSES diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index bac799b2fa8d..b8bd1199686e 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -5,6 +5,7 @@ obj-$(CONFIG_NVMEM) += nvmem_core.o nvmem_core-y := core.o +obj-y += layouts/ # Devices obj-$(CONFIG_NVMEM_APPLE_EFUSES) += nvmem-apple-efuses.o diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index c640d411ab15..164511537082 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -40,6 +40,7 @@ struct nvmem_device { nvmem_reg_write_t reg_write; nvmem_cell_post_process_t cell_post_process; struct gpio_desc *wp_gpio; + struct nvmem_layout *layout; void *priv; }; @@ -74,6 +75,9 @@ static LIST_HEAD(nvmem_lookup_list); static BLOCKING_NOTIFIER_HEAD(nvmem_notifier); +static DEFINE_SPINLOCK(nvmem_layout_lock); +static LIST_HEAD(nvmem_layouts); + static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, void *val, size_t bytes) { @@ -734,6 +738,75 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem) return 0; } +int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner) +{ + layout->owner = owner; + + spin_lock(&nvmem_layout_lock); + list_add(&layout->node, &nvmem_layouts); + spin_unlock(&nvmem_layout_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(__nvmem_layout_register); + +void nvmem_layout_unregister(struct nvmem_layout *layout) +{ + spin_lock(&nvmem_layout_lock); + list_del(&layout->node); + spin_unlock(&nvmem_layout_lock); +} +EXPORT_SYMBOL_GPL(nvmem_layout_unregister); + +static struct nvmem_layout *nvmem_layout_get(struct nvmem_device *nvmem) +{ + struct device_node *np = nvmem->dev.of_node; + struct nvmem_layout *l, *layout = NULL; + + spin_lock(&nvmem_layout_lock); + + list_for_each_entry(l, &nvmem_layouts, node) { + if (!of_match_node(l->of_match_table, np)) + continue; + + if (try_module_get(l->owner)) + layout = l; + + break; + } + + spin_unlock(&nvmem_layout_lock); + + return layout; +} + +static void nvmem_layout_put(struct nvmem_layout *layout) +{ + if (layout) + module_put(layout->owner); +} + +static int nvmem_add_cells_from_layout(struct nvmem_device *nvmem) +{ + struct nvmem_layout *layout = nvmem->layout; + + if (layout && layout->add_cells) + layout->add_cells(&nvmem->dev, nvmem, layout); + + return 0; +} + +const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem, + struct nvmem_layout *layout) +{ + const struct of_device_id *match; + + match = of_match_node(layout->of_match_table, nvmem->dev.of_node); + + return match ? match->data : NULL; +} +EXPORT_SYMBOL_GPL(nvmem_layout_get_match_data); + /** * nvmem_register() - Register a nvmem device for given nvmem_config. * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem @@ -848,6 +921,12 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) goto err_device_del; } + /* + * If the driver supplied a layout by config->layout, the module + * pointer will be NULL and nvmem_layout_put() will be a noop. + */ + nvmem->layout = config->layout ?: nvmem_layout_get(nvmem); + if (config->cells) { rval = nvmem_add_cells(nvmem, config->cells, config->ncells); if (rval) @@ -862,6 +941,10 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) if (rval) goto err_remove_cells; + rval = nvmem_add_cells_from_layout(nvmem); + if (rval) + goto err_remove_cells; + blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem); return nvmem; @@ -871,6 +954,7 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) err_teardown_compat: if (config->compat) nvmem_sysfs_remove_compat(nvmem, config); + nvmem_layout_put(nvmem->layout); err_device_del: device_del(&nvmem->dev); err_put_device: @@ -892,6 +976,7 @@ static void nvmem_device_release(struct kref *kref) device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); nvmem_device_remove_all_cells(nvmem); + nvmem_layout_put(nvmem->layout); device_unregister(&nvmem->dev); } diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig new file mode 100644 index 000000000000..9ad3911d1605 --- /dev/null +++ b/drivers/nvmem/layouts/Kconfig @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 + +menu "Layout Types" + +endmenu diff --git a/drivers/nvmem/layouts/Makefile b/drivers/nvmem/layouts/Makefile new file mode 100644 index 000000000000..6fdb3c60a4fa --- /dev/null +++ b/drivers/nvmem/layouts/Makefile @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for nvmem layouts. +# diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h index 72accdbe1d96..8a41bb30fc87 100644 --- a/include/linux/nvmem-provider.h +++ b/include/linux/nvmem-provider.h @@ -89,6 +89,7 @@ struct nvmem_cell_info { * @priv: User context passed to read/write callbacks. * @wp-gpio: Write protect pin * @ignore_wp: Write Protect pin is managed by the provider. + * @layout: Fixed layout associated with this nvmem device. * * Note: A default "nvmem" name will be assigned to the device if * no name is specified in its configuration. In such case "" is @@ -111,6 +112,7 @@ struct nvmem_config { bool read_only; bool root_only; bool ignore_wp; + struct nvmem_layout *layout; struct device_node *of_node; bool no_of_node; nvmem_reg_read_t reg_read; @@ -144,6 +146,33 @@ struct nvmem_cell_table { struct list_head node; }; +/** + * struct nvmem_layout - NVMEM layout definitions + * + * @name: Layout name. + * @of_match_table: Open firmware match table. + * @add_cells: Will be called if a nvmem device is found which + * has this layout. The function will add layout + * specific cells with nvmem_add_one_cell(). + * @owner: Pointer to struct module. + * @node: List node. + * + * A nvmem device can hold a well defined structure which can just be + * evaluated during runtime. For example a TLV list, or a list of "name=val" + * pairs. A nvmem layout can parse the nvmem device and add appropriate + * cells. + */ +struct nvmem_layout { + const char *name; + const struct of_device_id *of_match_table; + int (*add_cells)(struct device *dev, struct nvmem_device *nvmem, + struct nvmem_layout *layout); + + /* private */ + struct module *owner; + struct list_head node; +}; + #if IS_ENABLED(CONFIG_NVMEM) struct nvmem_device *nvmem_register(const struct nvmem_config *cfg); @@ -158,6 +187,14 @@ void nvmem_del_cell_table(struct nvmem_cell_table *table); int nvmem_add_one_cell(struct nvmem_device *nvmem, const struct nvmem_cell_info *info); +int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner); +#define nvmem_layout_register(layout) \ + __nvmem_layout_register(layout, THIS_MODULE) +void nvmem_layout_unregister(struct nvmem_layout *layout); + +const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem, + struct nvmem_layout *layout); + #else static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c) @@ -178,5 +215,19 @@ static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {} static inline int nvmem_add_one_cell(struct nvmem_device *nvmem, const struct nvmem_cell_info *info) {} +static inline int nvmem_layout_register(struct nvmem_layout *layout) +{ + return -EOPNOTSUPP; +} + +static inline void nvmem_layout_unregister(struct nvmem_layout *layout) {} + +static inline const void * +nvmem_layout_get_match_data(struct nvmem_device *nvmem, + struct nvmem_layout *layout) +{ + return NULL; +} + #endif /* CONFIG_NVMEM */ #endif /* ifndef _LINUX_NVMEM_PROVIDER_H */