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authorGatien Chevallier2024-01-05 14:03:56 +0100
committerAlexandre Torgue2024-04-05 16:49:14 +0200
commit5c9668cfc6d7c7de30fa57fa0a6c0ddc93462969 (patch)
treeba9617ce9b6aaa5b1285f538c7601d4944ac0020 /include
parentc1c67654df0713539f9b5e8f84ce8fc573465efb (diff)
firewall: introduce stm32_firewall framework
Introduce a STM32 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 STM32 firewall framework offers a generic API for STM32 firewall controllers that is defined in their 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 -No type for undefined type of firewall Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com> Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Diffstat (limited to 'include')
-rw-r--r--include/linux/bus/stm32_firewall_device.h142
1 files changed, 142 insertions, 0 deletions
diff --git a/include/linux/bus/stm32_firewall_device.h b/include/linux/bus/stm32_firewall_device.h
new file mode 100644
index 000000000000..18e0a2fc3816
--- /dev/null
+++ b/include/linux/bus/stm32_firewall_device.h
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023, STMicroelectronics - All Rights Reserved
+ */
+
+#ifndef STM32_FIREWALL_DEVICE_H
+#define STM32_FIREWALL_DEVICE_H
+
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#define STM32_FIREWALL_MAX_EXTRA_ARGS 5
+
+/* Opaque reference to stm32_firewall_controller */
+struct stm32_firewall_controller;
+
+/**
+ * struct 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
+ * @entry: Name of the firewall entry
+ * @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];
+ const char *entry;
+ 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 each of the access-controller property entries.
+ * The firewall ID is always the second argument of each of the
+ * access-controller property entries.
+ * If there's no argument linked to the phandle, then the firewall ID
+ * field is set to U32_MAX, which is an invalid ID.
+ *
+ * @np: Device node to parse
+ * @firewall: Array of firewall references
+ * @nb_firewall: Number of firewall references to get. Must be at least 1.
+ *
+ * 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,
+ unsigned int nb_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,
+ unsigned int nb_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 */