ipc: Added IPC Service to support different transport backends

IPC Service allow plugging in different transport backends.
Specifies a generic API that is implemented by the backend.

Signed-off-by: Marcin Jeliński <marcin.jelinski@nordicsemi.no>

include/ipc/ipc_service.h

@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_IPC_SERVICE_IPC_SERVICE_H_
+#define ZEPHYR_INCLUDE_IPC_SERVICE_IPC_SERVICE_H_
+
+#include <stdio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief IPC Service API
+ * @defgroup ipc_service_api IPC service APIs
+ * @{
+ */
+
+/** @brief Event callback structure.
+ *
+ *  It is registered during endpoint registration.
+ *  This structure is part of the endpoint configuration.
+ */
+struct ipc_service_cb {
+	/** @brief Bind was successful.
+	 *
+	 *  @param priv Private user data.
+	 */
+	void (*bound)(void *priv);
+
+	/** @brief New packet arrived.
+	 *
+	 *  @param data Pointer to data buffer.
+	 *  @param len Length of @a data.
+	 *  @param priv Private user data.
+	 */
+	void (*received)(const void *data, size_t len, void *priv);
+
+	/** @brief An error occurred.
+	 *
+	 *  @param message Error message.
+	 *  @param priv Private user data.
+	 */
+	void (*error)(const char *message, void *priv);
+};
+
+/** @brief Endpoint instance.
+ *
+ *  Content is not important for user of the API.
+ *  It is implemented in a specific backend.
+ */
+struct ipc_ept;
+
+/** @brief Endpoint configuration structure. */
+struct ipc_ept_cfg {
+
+	/** Name of the endpoint. */
+	const char *name;
+
+	/** Endpoint priority. If the backend supports priorities. */
+	int prio;
+
+	/** Event callback structure. */
+	struct ipc_service_cb cb;
+
+	/** Private user data. */
+	void *priv;
+};
+
+/** @brief Register IPC endpoint.
+ *
+ *  Registers IPC endpoint to enable communication with a remote device.
+ *
+ *  The same function registers endpoints for both master and slave devices.
+ *
+ *  @param ept Endpoint object.
+ *  @param cfg Endpoint configuration.
+ *
+ *  @retval -EIO when no backend is registered.
+ *  @retval -EINVAL when pointer to an endpoint or endpoint configuration is invalid.
+ *  @retval Other errno codes depending on the implementation of the backend.
+ */
+int ipc_service_register_endpoint(struct ipc_ept **ept, const struct ipc_ept_cfg *cfg);
+
+/** @brief Send data using given IPC endpoint.
+ *
+ *  @param ept Registered endpoint by @ref ipc_service_register_endpoint.
+ *  @param data Pointer to the buffer to send.
+ *  @param len Number of bytes to send.
+ *
+ *  @retval -EIO when no backend is registered.
+ *  @retval Other errno codes depending on the implementation of the backend.
+ */
+int ipc_service_send(struct ipc_ept *ept, const void *data, size_t len);
+
+/**
+ * @}
+ */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ZEPHYR_INCLUDE_IPC_SERVICE_IPC_SERVICE_H_ */

include/ipc/ipc_service_backend.h

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_IPC_SERVICE_IPC_SERVICE_BACKEND_H_
+#define ZEPHYR_INCLUDE_IPC_SERVICE_IPC_SERVICE_BACKEND_H_
+
+#include <ipc/ipc_service.h>
+#include <stdio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief IPC Service backend
+ * @ingroup ipc_service_api
+ * @{
+ */
+
+/** @brief IPC backend configuration structure.
+ *
+ *  This structure is used for configuration backend during registration.
+ */
+struct ipc_service_backend {
+	/** @brief Name of the IPC backend. */
+	const char *name;
+
+	/** @brief Pointer to the function that will be used to send data to the endpoint.
+	 *
+	 *  @param ept Registered endpoint.
+	 *  @param data Pointer to the buffer to send.
+	 *  @param len Number of bytes to send.
+	 *
+	 *  @retval Status code.
+	 */
+	int (*send)(struct ipc_ept *ept, const void *data, size_t len);
+
+	/** @brief Pointer to the function that will be used to register endpoints.
+	 *
+	 *  @param ept Endpoint object.
+	 *  @param cfg Endpoint configuration.
+	 *
+	 *  @retval Status code.
+	 */
+	int (*register_endpoint)(struct ipc_ept **ept, const struct ipc_ept_cfg *cfg);
+};
+
+/** @brief IPC backend registration.
+ *
+ *  Registration must be done before using IPC Service.
+ *
+ *  @param backend Configuration of the backend.
+ *
+ *  @retval -EALREADY The backend is already registered.
+ *  @retval -EINVAL The backend configuration is incorrect.
+ *  @retval Zero on success.
+ *
+ */
+int ipc_service_register_backend(const struct ipc_service_backend *backend);
+
+/**
+ * @}
+ */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ZEPHYR_INCLUDE_IPC_SERVICE_IPC_SERVICE_BACKEND_H_ */

subsys/ipc/CMakeLists.txt

@@ -2,3 +2,4 @@
 
 add_subdirectory_ifdef(CONFIG_RPMSG_SERVICE rpmsg_service)
 add_subdirectory_ifdef(CONFIG_RPMSG_MULTI_INSTANCE rpmsg_multi_instance)
+add_subdirectory_ifdef(CONFIG_IPC_SERVICE ipc_service)

subsys/ipc/Kconfig

@@ -7,5 +7,6 @@ menu "Inter Processor Communication"
 
 source "subsys/ipc/rpmsg_service/Kconfig"
 source "subsys/ipc/rpmsg_multi_instance/Kconfig"
+source "subsys/ipc/ipc_service/Kconfig"
 
 endmenu

subsys/ipc/ipc_service/CMakeLists.txt

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_sources(ipc_service.c)

subsys/ipc/ipc_service/Kconfig

@@ -0,0 +1,32 @@
+# Copyright (c) -2021 Nordic Semiconductor (ASA)
+# SPDX-License-Identifier: Apache-2.0
+
+menuconfig IPC_SERVICE
+	bool "IPC service support multiple backends"
+	help
+	  Enables support for a service that can be shared by multiple
+	  users. Ability to work in different backends. The backend
+	  should be registered before application starts using
+	  the IPC Service.
+
+if IPC_SERVICE
+
+choice IPC_SERVICE_BACKEND
+	prompt "IPC Service backend"
+
+config IPC_SERVICE_BACKEND_XYZ
+	bool "Example backend"
+
+endchoice
+
+config IPC_SERVICE_BACKEND_REG_PRIORITY
+	int "Initialization priority of modules registering IPC backend"
+	default 46
+	help
+	  The backend must be registered before the endpoint register.
+
+module = IPC_SERVICE
+module-str = IPC service and backend
+source "${ZEPHYR_BASE}/subsys/logging/Kconfig.template.log_config"
+
+endif # IPC_SERVICE

subsys/ipc/ipc_service/ipc_service.c

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <ipc/ipc_service.h>
+#include <ipc/ipc_service_backend.h>
+
+#include <logging/log.h>
+#include <zephyr.h>
+#include <device.h>
+
+#define LOG_MODULE_NAME ipc_service
+LOG_MODULE_REGISTER(LOG_MODULE_NAME, CONFIG_IPC_SERVICE_LOG_LEVEL);
+
+const static struct ipc_service_backend *backend;
+
+int ipc_service_register_backend(const struct ipc_service_backend *bkd)
+{
+	if (backend) {
+		return -EALREADY;
+	}
+
+	if (!bkd || !bkd->register_endpoint || !bkd->send) {
+		return -EINVAL;
+	}
+
+	backend = bkd;
+	LOG_DBG("Registered: %s", backend->name ? backend->name : "");
+
+	return 0;
+}
+
+int ipc_service_register_endpoint(struct ipc_ept **ept, const struct ipc_ept_cfg *cfg)
+{
+	LOG_DBG("Register endpoint %s", cfg->name ? cfg->name : "");
+	if (!backend || !backend->register_endpoint) {
+		LOG_ERR("Backend not registered");
+		return -EIO;
+	}
+
+	if (!ept || !cfg) {
+		LOG_ERR("Invalid endpoint or configuration");
+		return -EINVAL;
+	}
+
+	return backend->register_endpoint(ept, cfg);
+}
+
+int ipc_service_send(struct ipc_ept *ept, const void *data, size_t len)
+{
+	if (!backend || !backend->send) {
+		LOG_ERR("Backend not registered");
+		return -EIO;
+	}
+
+	return backend->send(ept, data, len);
+}