schedule: zephyr_ll: add user_ll_grant_access()

Add function user_ll_grant_access() to allow other threads
to access the scheduler mutex. This is needed if work is submitted
from other threads to the scheduler.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

src/include/sof/schedule/ll_schedule_domain.h

@@ -120,6 +120,7 @@ struct task *zephyr_ll_task_alloc(void);
 struct k_heap *zephyr_ll_user_heap(void);
 bool zephyr_ll_user_heap_verify(struct k_heap *heap);
 void zephyr_ll_user_resources_init(void);
+void user_ll_grant_access(struct k_thread *thread, int core);
 void user_ll_lock_sched(int core);
 void user_ll_unlock_sched(int core);
 #ifdef CONFIG_ASSERT

src/schedule/zephyr_ll.c

@@ -626,6 +626,13 @@ struct task *zephyr_ll_task_alloc(void)
 	return task;
 }
 
+void user_ll_grant_access(struct k_thread *thread, int core)
+{
+	assert(core < CONFIG_CORE_COUNT && zephyr_ll_locks[core] != NULL);
+
+	k_thread_access_grant(thread, zephyr_ll_locks[core]);
+}
+
 /**
  * Lock the LL scheduler to prevent it from processing tasks.
  *