From patchwork Wed Jul 5 17:27:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gatien CHEVALLIER X-Patchwork-Id: 13302485 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 E7320C001DE for ; Wed, 5 Jul 2023 17:30:44 +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=39AEydY035vEXBPrxWHRpgS5BeFAPdr03d01X0YCj/E=; b=LOSC6gjAreS2q/ 2bK0O8mPf6T+4AEfslbVIqPBIc0dh1TxUDNcGBong/ScMU9iLU9dF+YLWrspwWV7Vi4Cmv3Hy4HTm OP7WOaMbxGogyNG4nl+WlHNFgETsw49ciQPgwW6uLDvkYvTYTWMGWPiVxA4xyyEXYbAzt9Bt7LxE1 wcBe/QaY9nsgK+VKzkMVVgRn2L/PMq2eelsjPjTGjOMkCZ+EH4pshFbSy6W5ebH2qIwdJERBlof4u 1pwiKoMpa3Ch9iTvxVLxnH1yttPCXSWdClmuuqkKYrgLvkBgORUz/uoRCNZnLB2XInTtbk/oKHNjR lRIb4JE3KjO+pyOlMHSw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qH6KX-00GcLh-1R; Wed, 05 Jul 2023 17:30:17 +0000 Received: from mx07-00178001.pphosted.com ([185.132.182.106]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qH6KO-00GcET-1r; Wed, 05 Jul 2023 17:30:11 +0000 Received: from pps.filterd (m0241204.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 365ELI2q007748; Wed, 5 Jul 2023 19:29:46 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=selector1; bh=x9bigIC8n5cdT6pnsBrsJD/UDtYoojAZBfPWBmQH74M=; b=vxUYuVKru/d22a1Xe/qxmxpmi5wukrbDV6iOp9U4miU/7Ji3GYIYuArMjnFJdO+DzFKE hfpAZovIAbAjhJmVdHww4PEXwOnAAKVKNDkfKMAhSG9a4uJ5dW3jvzha+cEDoeBRk0sb QapfdEKGXG8xjEqMrPEs79siI2iQN+R3WbZtHGDlnAT9HLgxufAYLHeOaqXFtms3WWI2 ghfRoBw0pMuQSo/UfY/sxo+NT9+g/BXmMxtfU7Ne+P8HUoHZzYBVOKACgJOaJYcmEKdD UQugOzjfTvN7INSO4xq2O+CkQIe1Cpk4xbZKXLR3zle5+SpE4Pqp0QNMz4GAcWkpY6oS xA== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com (PPS) with ESMTPS id 3rna75h452-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 05 Jul 2023 19:29:46 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 5BB2D100057; Wed, 5 Jul 2023 19:29:45 +0200 (CEST) Received: from Webmail-eu.st.com (shfdag1node1.st.com [10.75.129.69]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 4FE7C24C434; Wed, 5 Jul 2023 19:29:45 +0200 (CEST) Received: from localhost (10.201.21.121) by SHFDAG1NODE1.st.com (10.75.129.69) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Wed, 5 Jul 2023 19:29:44 +0200 From: Gatien Chevallier To: , , , , , , , , , , , , , , , , , , , , , , , , CC: , , , , , , , , , , , , , , , , Gatien Chevallier Subject: [PATCH 05/10] firewall: introduce stm32_firewall framework Date: Wed, 5 Jul 2023 19:27:54 +0200 Message-ID: <20230705172759.1610753-6-gatien.chevallier@foss.st.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230705172759.1610753-1-gatien.chevallier@foss.st.com> References: <20230705172759.1610753-1-gatien.chevallier@foss.st.com> MIME-Version: 1.0 X-Originating-IP: [10.201.21.121] X-ClientProxiedBy: SHFCAS1NODE1.st.com (10.75.129.72) To SHFDAG1NODE1.st.com (10.75.129.69) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-07-05_09,2023-07-05_01,2023-05-22_02 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230705_103008_910887_09CDD9D7 X-CRM114-Status: GOOD ( 31.81 ) 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 Introduce a firewall framework that offers to firewall consumers different firewall services such as the ability to check their access rights against their firewall controller(s). The firewall framework offers a generic API that is defined in firewall controllers drivers to best fit the specificity of each firewall. There are various types of firewalls: -Peripheral firewalls that filter accesses to peripherals -Memory firewalls that filter accesses to memories or memory regions -Resource firewalls that filter accesses to internal resources such as reset and clock controllers A firewall controller must be probed at arch_initcall level and register to the framework so that consumers can use their services. Signed-off-by: Gatien Chevallier --- MAINTAINERS | 5 + arch/arm64/Kconfig.platforms | 1 + drivers/bus/Kconfig | 10 + drivers/bus/Makefile | 1 + drivers/bus/stm32_firewall.c | 252 ++++++++++++++++++++++ drivers/bus/stm32_firewall.h | 83 +++++++ include/linux/bus/stm32_firewall_device.h | 134 ++++++++++++ 7 files changed, 486 insertions(+) create mode 100644 drivers/bus/stm32_firewall.c create mode 100644 drivers/bus/stm32_firewall.h create mode 100644 include/linux/bus/stm32_firewall_device.h diff --git a/MAINTAINERS b/MAINTAINERS index 41385f01fa98..fabf95ba9b86 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20123,6 +20123,11 @@ T: git git://linuxtv.org/media_tree.git F: Documentation/devicetree/bindings/media/i2c/st,st-mipid02.yaml F: drivers/media/i2c/st-mipid02.c +ST STM32 FIREWALL +M: Gatien Chevallier +S: Maintained +F: drivers/bus/stm32_firewall.c + ST STM32 I2C/SMBUS DRIVER M: Pierre-Yves MORDRET M: Alain Volmat diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms index 6069120199bb..5a46e90f1e4e 100644 --- a/arch/arm64/Kconfig.platforms +++ b/arch/arm64/Kconfig.platforms @@ -293,6 +293,7 @@ config ARCH_STM32 select ARM_SMC_MBOX select ARM_SCMI_PROTOCOL select COMMON_CLK_SCMI + select STM32_FIREWALL help This enables support for ARMv8 based STMicroelectronics STM32 family, including: diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig index fcfa280df98a..4d54a7ea52b2 100644 --- a/drivers/bus/Kconfig +++ b/drivers/bus/Kconfig @@ -163,6 +163,16 @@ config QCOM_SSC_BLOCK_BUS i2c/spi/uart controllers, a hexagon core, and a clock controller which provides clocks for the above. +config STM32_FIREWALL + bool "STM32 Firewall framework" + depends on ARCH_STM32 + default MACH_STM32MP157 || MACH_STM32MP13 || MACH_STM32MP25 + help + Say y to enable firewall framework and its services. Firewall + controllers will be able to register to the framework. Firewall + controllers must be initialized and register to the firewall framework + at arch_initcall level. + config SUN50I_DE2_BUS bool "Allwinner A64 DE2 Bus Driver" default ARM64 diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile index d90eed189a65..fc0511450ec2 100644 --- a/drivers/bus/Makefile +++ b/drivers/bus/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_OMAP_INTERCONNECT) += omap_l3_smx.o omap_l3_noc.o obj-$(CONFIG_OMAP_OCP2SCP) += omap-ocp2scp.o obj-$(CONFIG_QCOM_EBI2) += qcom-ebi2.o obj-$(CONFIG_QCOM_SSC_BLOCK_BUS) += qcom-ssc-block-bus.o +obj-$(CONFIG_STM32_FIREWALL) += stm32_firewall.o obj-$(CONFIG_SUN50I_DE2_BUS) += sun50i-de2.o obj-$(CONFIG_SUNXI_RSB) += sunxi-rsb.o obj-$(CONFIG_OF) += simple-pm-bus.o diff --git a/drivers/bus/stm32_firewall.c b/drivers/bus/stm32_firewall.c new file mode 100644 index 000000000000..510db5bc6eaf --- /dev/null +++ b/drivers/bus/stm32_firewall.c @@ -0,0 +1,252 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2023, STMicroelectronics - All Rights Reserved + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "stm32_firewall.h" + +/* Corresponds to STM32_FIREWALL_MAX_EXTRA_ARGS + firewall controller reference + firewall ID */ +#define STM32_FIREWALL_MAX_ARGS (STM32_FIREWALL_MAX_EXTRA_ARGS + 2) + +static LIST_HEAD(firewall_controller_list); +static DEFINE_MUTEX(firewall_controller_list_lock); + +static int stm32_firewall_get_id(struct device_node *np, u32 *id) +{ + u32 feature_domain_cell[2]; + + /* Get property from device node */ + if (of_property_read_u32_array(np, "feature-domains", + feature_domain_cell, + ARRAY_SIZE(feature_domain_cell))) { + pr_err("Unable to find get firewall ID property\n"); + return -ENODEV; + } + + *id = feature_domain_cell[1]; + + return 0; +} + +/* Firewall device API */ + +int stm32_firewall_get_firewall(struct device_node *np, + struct stm32_firewall *firewall) +{ + struct stm32_firewall_controller *ctrl; + struct of_phandle_args args; + u32 controller_phandle; + bool match = false; + size_t i; + int err; + + if (!firewall) + return -EINVAL; + + /* The controller phandle is always the first argument of the feature-domains property. */ + err = of_property_read_u32(np, "feature-domains", &controller_phandle); + if (err) { + pr_err("Unable to get feature-domains property for node %s\n", np->full_name); + return err; + } + + /* Parse property with phandle parsed out */ + err = of_parse_phandle_with_args(np, "feature-domains", "#feature-domain-cells", 0, &args); + if (err) { + pr_err("Unable to read feature-domains arguments for node %s\n", np->full_name); + return err; + } + + /* The phandle is parsed out */ + if (args.args_count > STM32_FIREWALL_MAX_ARGS - 1) + return -EINVAL; + + of_node_put(np); + + /* Check if the parsed phandle corresponds to a registered firewall controller */ + mutex_lock(&firewall_controller_list_lock); + list_for_each_entry(ctrl, &firewall_controller_list, entry) { + if (ctrl->dev->of_node->phandle == controller_phandle) { + match = true; + firewall->firewall_ctrl = ctrl; + break; + } + } + mutex_unlock(&firewall_controller_list_lock); + if (!match) { + firewall->firewall_ctrl = NULL; + pr_err("No firewall controller registered for %s\n", np->full_name); + return -ENODEV; + } + + /* + * The firewall ID is always the second argument of the feature-domains property. + * The first argument is already parsed out, so args.args[0] is the second argument. + */ + firewall->firewall_id = args.args[0]; + + /* Extra args start at the third argument */ + for (i = 0; i < args.args_count; i++) + firewall->extra_args[i] = args.args[i + 1]; + + /* Remove the firewall ID arg that is not an extra argument */ + if (args.args_count >= 1) + firewall->extra_args_size = args.args_count - 1; + + return 0; +} +EXPORT_SYMBOL_GPL(stm32_firewall_get_firewall); + +int stm32_firewall_grant_access(struct stm32_firewall *firewall) +{ + struct stm32_firewall_controller *firewall_controller; + + if (!firewall || firewall->firewall_id == U32_MAX) + return -EINVAL; + + firewall_controller = firewall->firewall_ctrl; + + if (!firewall_controller) + return -ENODEV; + + return firewall_controller->grant_access(firewall_controller, firewall->firewall_id); +} +EXPORT_SYMBOL_GPL(stm32_firewall_grant_access); + +int stm32_firewall_grant_access_by_id(struct stm32_firewall *firewall, u32 subsystem_id) +{ + struct stm32_firewall_controller *firewall_controller; + + if (!firewall || subsystem_id == U32_MAX || firewall->firewall_id == U32_MAX) + return -EINVAL; + + firewall_controller = firewall->firewall_ctrl; + + if (!firewall_controller) + return -ENODEV; + + return firewall_controller->grant_access(firewall_controller, subsystem_id); +} +EXPORT_SYMBOL_GPL(stm32_firewall_grant_access_by_id); + +void stm32_firewall_release_access(struct stm32_firewall *firewall) +{ + struct stm32_firewall_controller *firewall_controller; + + if (!firewall || firewall->firewall_id == U32_MAX) { + pr_err("Incorrect arguments when releasing a firewall access"); + return; + } + + firewall_controller = firewall->firewall_ctrl; + + if (!firewall_controller) { + pr_debug("No firewall controller to release"); + return; + } + + firewall_controller->release_access(firewall_controller, firewall->firewall_id); +} +EXPORT_SYMBOL_GPL(stm32_firewall_release_access); + +void stm32_firewall_release_access_by_id(struct stm32_firewall *firewall, u32 subsystem_id) +{ + struct stm32_firewall_controller *firewall_controller; + + if (!firewall || subsystem_id == U32_MAX || firewall->firewall_id == U32_MAX) { + pr_err("Incorrect arguments when releasing a firewall access"); + return; + } + + firewall_controller = firewall->firewall_ctrl; + + if (!firewall_controller) { + pr_debug("No firewall controller to release"); + return; + } + + firewall_controller->release_access(firewall_controller, subsystem_id); +} +EXPORT_SYMBOL_GPL(stm32_firewall_release_access_by_id); + +/* Firewall controller API */ + +int stm32_firewall_controller_register(struct stm32_firewall_controller *firewall_controller) +{ + pr_info("Registering firewall controller %s", dev_name(firewall_controller->dev)); + + if (!firewall_controller) + return -ENODEV; + + mutex_lock(&firewall_controller_list_lock); + list_add_tail(&firewall_controller->entry, &firewall_controller_list); + mutex_unlock(&firewall_controller_list_lock); + + return 0; + +} + +void stm32_firewall_controller_unregister(struct stm32_firewall_controller *firewall_controller) +{ + struct stm32_firewall_controller *ctrl, *tmp; + bool controller_removed = false; + + if (!firewall_controller) { + pr_debug("Null reference while unregistering firewall controller"); + return; + } + + mutex_lock(&firewall_controller_list_lock); + list_for_each_entry_safe(ctrl, tmp, &firewall_controller_list, entry) { + if (ctrl == firewall_controller) { + controller_removed = true; + list_del_init(&ctrl->entry); + break; + } + } + mutex_unlock(&firewall_controller_list_lock); + + if (!controller_removed) + pr_debug("There was no firewall controller named %s to unregister", + dev_name(firewall_controller->dev)); +} + +void stm32_firewall_populate_bus(struct stm32_firewall_controller *firewall_controller) +{ + struct device_node *child; + struct device *parent; + u32 firewall_id; + int err; + + parent = firewall_controller->dev; + + dev_dbg(parent, "Populating %s system bus\n", dev_name(firewall_controller->dev)); + + for_each_available_child_of_node(dev_of_node(parent), child) { + err = stm32_firewall_get_id(child, &firewall_id); + if (err < 0 || + firewall_controller->grant_access(firewall_controller, firewall_id)) { + /* + * Peripheral access not allowed or not defined. + * Mark the node as populated so platform bus won't probe it + */ + of_node_set_flag(child, OF_POPULATED); + dev_err(parent, "%s: Device driver will not be probed\n", + child->full_name); + } + } +} diff --git a/drivers/bus/stm32_firewall.h b/drivers/bus/stm32_firewall.h new file mode 100644 index 000000000000..8d92e8c1ab77 --- /dev/null +++ b/drivers/bus/stm32_firewall.h @@ -0,0 +1,83 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2023, STMicroelectronics - All Rights Reserved + */ + +#ifndef _STM32_FIREWALL_H +#define _STM32_FIREWALL_H + +#include +#include +#include +#include +#include + +/** + * STM32_PERIPHERAL_FIREWALL: This type of firewall protects peripherals + * STM32_MEMORY_FIREWALL: This type of firewall protects memories/subsets of memory + * zones + * STM32_RESOURCE_FIREWALL: This type of firewall protects internal resources + * STM32_NOTYPE_FIREWALL: Undefined firewall type + */ + +#define STM32_PERIPHERAL_FIREWALL BIT(1) +#define STM32_MEMORY_FIREWALL BIT(2) +#define STM32_RESOURCE_FIREWALL BIT(3) +#define STM32_NOTYPE_FIREWALL BIT(4) + +/** + * struct stm32_firewall_controller - Information on firewall controller supplying services + * + * @name Name of the firewall controller + * @dev Device reference of the firewall controller + * @mmio Base address of the firewall controller + * @entry List entry of the firewall controller list + * @type Type of firewall + * @max_entries Number of entries covered by the firewall + * @grant_access Callback used to grant access for a device access against a + * firewall controller + * @release_access Callback used to release resources taken by a device when access was + * granted + * @grant_memory_range_access Callback used to grant access for a device to a given memory region + */ +struct stm32_firewall_controller { + const char *name; + struct device *dev; + void __iomem *mmio; + struct list_head entry; + unsigned int type; + unsigned int max_entries; + + int (*grant_access)(struct stm32_firewall_controller *ctrl, u32 id); + void (*release_access)(struct stm32_firewall_controller *ctrl, u32 id); + int (*grant_memory_range_access)(struct stm32_firewall_controller *ctrl, phys_addr_t paddr, + size_t size); +}; + +/** + * int stm32_firewall_controller_register - Register a firewall controller to the STM32 firewall + * framework + * @firewall_controller Firewall controller to register + * + * Returns 0 in case of success or -ENODEV if no controller was given. + */ +int stm32_firewall_controller_register(struct stm32_firewall_controller *firewall_controller); + +/** + * int stm32_firewall_controller_unregister - Unregister a firewall controller from the STM32 + * firewall framework + * @firewall_controller Firewall controller to unregister + */ +void stm32_firewall_controller_unregister(struct stm32_firewall_controller *firewall_controller); + +/** + * stm32_firewall_populate_bus - Populate device tree nodes that have a correct firewall + * configuration. This is used at boot-time only, as a sanity check + * between device tree and firewalls hardware configurations to + * prevent a kernel crash when a device driver is not granted access + * + * @firewall_controller Firewall controller which nodes will be populated or not + */ +void stm32_firewall_populate_bus(struct stm32_firewall_controller *firewall_controller); + +#endif /* _STM32_FIREWALL_H */ diff --git a/include/linux/bus/stm32_firewall_device.h b/include/linux/bus/stm32_firewall_device.h new file mode 100644 index 000000000000..ccaecea7fc6c --- /dev/null +++ b/include/linux/bus/stm32_firewall_device.h @@ -0,0 +1,134 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2023, STMicroelectronics - All Rights Reserved + */ + +#ifndef STM32_FIREWALL_DEVICE_H +#define STM32_FIREWALL_DEVICE_H + +#include +#include +#include + +#define STM32_FIREWALL_MAX_EXTRA_ARGS 5 + +/* Opaque reference to stm32_firewall_controller */ +struct stm32_firewall_controller; + +/** + * stm32_firewall - Information on a device's firewall. Each device can have more than one firewall. + * + * @firewall_ctrl Pointer referencing a firewall controller of the device. It is + * opaque so a device cannot manipulate the controller's ops or access + * the controller's data + * @extra_args Extra arguments that are implementation dependent + * @extra_args_size Number of extra arguments + * @firewall_id Firewall ID associated the device for this firewall controller + */ +struct stm32_firewall { + struct stm32_firewall_controller *firewall_ctrl; + u32 extra_args[STM32_FIREWALL_MAX_EXTRA_ARGS]; + size_t extra_args_size; + u32 firewall_id; +}; + +#if IS_ENABLED(CONFIG_STM32_FIREWALL) +/** + * stm32_firewall_get_firewall - Get the firewall(s) associated to given device. + * The firewall controller reference is always the first argument + * of the feature-domains property. + * The firewall ID is always the second argument of the + * feature-domains property. + * + * @np Device node to parse + * @firewall Resulting firewall reference(s) + * + * Returns 0 on success, -ENODEV if there's no match with a firewall controller or appropriate errno + * code if error occurred. + */ +int stm32_firewall_get_firewall(struct device_node *np, struct stm32_firewall *firewall); + +/** + * stm32_firewall_grant_access - Request firewall access rights and grant access. + * + * @firewall Firewall reference containing the ID to check against its firewall + * controller + * + * Returns 0 if access is granted, -EACCES if access is denied, -ENODEV if firewall is null or + * appropriate errno code if error occurred + */ +int stm32_firewall_grant_access(struct stm32_firewall *firewall); + +/** + * stm32_firewall_release_access - Release access granted from a call to + * stm32_firewall_grant_access(). + * + * @firewall Firewall reference containing the ID to check against its firewall + * controller + */ +void stm32_firewall_release_access(struct stm32_firewall *firewall); + +/** + * stm32_firewall_grant_access_by_id - Request firewall access rights of a given device + * based on a specific firewall ID + * + * Warnings: + * There is no way to ensure that the given ID will correspond to the firewall referenced in the + * device node if the ID did not come from stm32_firewall_get_firewall(). In that case, this + * function must be used with caution. + * This function should be used for subsystem resources that do not have the same firewall ID + * as their parent. + * U32_MAX is an invalid ID. + * + * @firewall Firewall reference containing the firewall controller + * @subsystem_id Firewall ID of the subsystem resource + * + * Returns 0 if access is granted, -EACCES if access is denied, -ENODEV if firewall is null or + * appropriate errno code if error occurred + */ +int stm32_firewall_grant_access_by_id(struct stm32_firewall *firewall, u32 subsystem_id); + +/** + * stm32_firewall_release_access_by_id - Release access granted from a call to + * stm32_firewall_grant_access_by_id(). + * + * Warnings: + * There is no way to ensure that the given ID will correspond to the firewall referenced in the + * device node if the ID did not come from stm32_firewall_get_firewall(). In that case, this + * function must be used with caution. + * This function should be used for subsystem resources that do not have the same firewall ID + * as their parent. + * U32_MAX is an invalid ID. + * + * @firewall Firewall reference containing the firewall controller + * @subsystem_id Firewall ID of the subsystem resource + */ +void stm32_firewall_release_access_by_id(struct stm32_firewall *firewall, u32 subsystem_id); + +#else /* CONFIG_STM32_FIREWALL */ + +int stm32_firewall_get_firewall(struct device_node *np, struct stm32_firewall *firewall) +{ + return -ENODEV; +} + +int stm32_firewall_grant_access(struct stm32_firewall *firewall) +{ + return -ENODEV; +} + +void stm32_firewall_release_access(struct stm32_firewall *firewall) +{ +} + +int stm32_firewall_grant_access_by_id(struct stm32_firewall *firewall, u32 subsystem_id) +{ + return -ENODEV; +} + +void stm32_firewall_release_access_by_id(struct stm32_firewall *firewall, u32 subsystem_id) +{ +} + +#endif /* CONFIG_STM32_FIREWALL */ +#endif /* STM32_FIREWALL_DEVICE_H */