logging: Add ipc_service log backend

Added backend that sends messages over ipc_service. It uses
log_backend_remote and will talk to log_link_ipc_service based
on log_link_remote.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>

subsys/logging/CMakeLists.txt

@@ -70,7 +70,6 @@ if(NOT CONFIG_LOG_MODE_MINIMAL)
     log_multidomain_link.c
   )
 
-  endif()
 
 else()
   zephyr_sources(log_minimal.c)

subsys/logging/backends/CMakeLists.txt

@@ -69,3 +69,8 @@ zephyr_sources_ifdef(
   CONFIG_LOG_MULTIDOMAIN_BACKEND
   log_multidomain_backend.c
 )
+
+zephyr_sources_ifdef(
+  CONFIG_LOG_BACKEND_IPC_SERVICE
+  log_backend_ipc_service.c
+)

subsys/logging/backends/Kconfig.multidomain

@@ -5,3 +5,7 @@ config LOG_MULTIDOMAIN_BACKEND
 	bool
 	select LOG_TIMESTAMP_64BIT
 	select LOG_MSG_APPEND_RO_STRING_LOC
+
+config LOG_BACKEND_IPC_SERVICE
+	bool "IPC service backend"
+	select LOG_MULTIDOMAIN_BACKEND

subsys/logging/backends/log_backend_ipc_service.c

@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/ipc/ipc_service.h>
+#include <zephyr/logging/log_multidomain_helper.h>
+#include <zephyr/logging/log_backend.h>
+#include <zephyr/logging/log_ctrl.h>
+
+struct log_backend_ipc_service {
+	struct ipc_ept ept;
+	struct log_multidomain_backend backend_remote;
+};
+
+static void bound_cb(void *priv)
+{
+	struct log_multidomain_backend *backend_remote = priv;
+
+	log_multidomain_backend_on_started(backend_remote, 0);
+}
+
+static void error_cb(const char *message, void *priv)
+{
+	struct log_multidomain_backend *backend_remote = priv;
+
+	log_multidomain_backend_on_error(backend_remote, -EIO);
+}
+
+static void recv_cb(const void *data, size_t len, void *priv)
+{
+	struct log_multidomain_backend *backend_remote = priv;
+
+	log_multidomain_backend_on_recv_cb(backend_remote, data, len);
+}
+
+static int backend_ipc_service_send(struct log_multidomain_backend *backend_remote,
+				 void *data, size_t len)
+{
+	struct log_backend_ipc_service *backend_ipc_service =
+		CONTAINER_OF(backend_remote, struct log_backend_ipc_service, backend_remote);
+	int err = ipc_service_send(&backend_ipc_service->ept, data, len);
+
+	return err;
+}
+
+static int backend_ipc_service_init(struct log_multidomain_backend *backend_remote)
+{
+	struct log_backend_ipc_service *backend_ipc_service =
+		CONTAINER_OF(backend_remote, struct log_backend_ipc_service, backend_remote);
+	static struct ipc_ept_cfg ept_cfg = {
+		.name = "logging",
+		.prio = 0,
+		.cb = {
+			.bound    = bound_cb,
+			.received = recv_cb,
+			.error    = error_cb,
+		},
+	};
+	const struct device *ipc_instance = DEVICE_DT_GET(DT_CHOSEN(zephyr_log_ipc));
+	int err;
+
+	ept_cfg.priv = (void *)backend_remote;
+	err = ipc_service_open_instance(ipc_instance);
+	if (err < 0 && err != -EALREADY) {
+		return err;
+	}
+
+	err = ipc_service_register_endpoint(ipc_instance, &backend_ipc_service->ept, &ept_cfg);
+
+	return err;
+}
+
+struct log_multidomain_backend_transport_api log_backend_ipc_service_transport_api = {
+	.init = backend_ipc_service_init,
+	.send = backend_ipc_service_send
+};
+
+static struct log_backend_ipc_service backend_ipc_service_data = {
+	.backend_remote = {
+		.transport_api = &log_backend_ipc_service_transport_api
+	}
+};
+
+LOG_BACKEND_DEFINE(backend_ipc_service,
+		   log_multidomain_backend_api,
+		   true,
+		   &backend_ipc_service_data.backend_remote);