logging: init backend id regardless of autostart

The `id` is basically a compile-time constant. Setting it every
time the backend is enabled is unnecessary. Instead, set it on
`log_core_init()` regardless of whether or not it requires to be
`autostart`ed.

Fixes an issue where the `filter_get`/`filter_set`
accessed the wrong index and displayed the wrong log level when
user accesses the status of an uninitialized backend via:
`log backend <uninitialized_backend> status`.

Also fixes an issue when user tries to list the backends via:
`log list_backends`, where all uninitialized backends will have
ID = 0.

This commit is a combination of 8dd9d92 & dd9fd7d.

Signed-off-by: Yong Cong Sin <[email protected]>
Signed-off-by: Yong Cong Sin <[email protected]>

Author: ycsin

subsys/logging/log_core.c

@@ -286,6 +286,14 @@ void log_core_init(void)
 	if (IS_ENABLED(CONFIG_LOG_RUNTIME_FILTERING)) {
 		z_log_runtime_filters_init();
 	}
+
+	STRUCT_SECTION_FOREACH(log_backend, backend) {
+		uint32_t id;
+		/* As first slot in filtering mask is reserved, backend ID has offset.*/
+		id = LOG_FILTER_FIRST_BACKEND_SLOT_IDX;
+		id += backend - log_backend_get(0);
+		log_backend_id_set(backend, id);
+	}
 }
 
 static uint32_t activate_foreach_backend(uint32_t mask)

subsys/logging/log_mgmt.c

@@ -553,12 +553,6 @@ void log_backend_enable(struct log_backend const *const backend,
 			void *ctx,
 			uint32_t level)
 {
-	/* As first slot in filtering mask is reserved, backend ID has offset.*/
-	uint32_t id = LOG_FILTER_FIRST_BACKEND_SLOT_IDX;
-
-	id += backend - log_backend_get(0);
-
-	log_backend_id_set(backend, id);
 	backend->cb->level = level;
 	backend_filter_set(backend, level);
 	log_backend_activate(backend, ctx);