dp: switch the lock to use sys_sem

sys_sem semaphores don't invoke a syscall in uncongested cases.
Switch over to it to reduce syscall number.

Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>

Author: lyakh

src/schedule/zephyr_dp_schedule.c

@@ -33,36 +33,33 @@ SOF_DEFINE_REG_UUID(dp_sched);
 
 DECLARE_TR_CTX(dp_tr, SOF_UUID(dp_sched_uuid), LOG_LEVEL_INFO);
 
-#define DP_LOCK_INIT(i, _)	Z_SEM_INITIALIZER(dp_lock[i], 1, 1)
+#ifdef CONFIG_USERSPACE
+#define SYS_SEM_INITIALIZER(obj, n_init, n_max) {.futex = {n_init}, .limit = n_max}
+#else
+#define SYS_SEM_INITIALIZER(obj, n_init, n_max) {Z_SEM_INITIALIZER(obj.kernel_sem, 1, 1)}
+#endif
+
+#define DP_LOCK_INIT(i, _)	SYS_SEM_INITIALIZER(dp_lock[i], 1, 1)
 #define DP_LOCK_INIT_LIST	LISTIFY(CONFIG_MP_MAX_NUM_CPUS, DP_LOCK_INIT, (,))
 
-/* User threads don't need access to this array. Access is performed from
- * the kernel space via a syscall. Array must be placed in special section
- * to be qualified as initialized by the gen_kobject_list.py script.
- */
-static
-STRUCT_SECTION_ITERABLE_ARRAY(k_sem, dp_lock, CONFIG_MP_MAX_NUM_CPUS) = { DP_LOCK_INIT_LIST };
+static struct sys_sem dp_lock[CONFIG_MP_MAX_NUM_CPUS] = {
+	DP_LOCK_INIT_LIST
+};
 
 /* Each per-core instance of DP scheduler has separate structures; hence, locks are per-core.
  *
  * TODO: consider using cpu_get_id() instead of supplying core as a parameter.
  */
 unsigned int scheduler_dp_lock(uint16_t core)
 {
-	k_sem_take(&dp_lock[core], K_FOREVER);
+	sys_sem_take(&dp_lock[core], K_FOREVER);
+
 	return core;
 }
 
 void scheduler_dp_unlock(unsigned int key)
 {
-	k_sem_give(&dp_lock[key]);
-}
-
-void scheduler_dp_grant(k_tid_t thread_id, uint16_t core)
-{
-#if CONFIG_USERSPACE
-	k_thread_access_grant(thread_id, &dp_lock[core]);
-#endif
+	sys_sem_give(&dp_lock[key]);
 }
 
 /* dummy LL task - to start LL on secondary cores */

src/schedule/zephyr_dp_schedule.h

@@ -55,7 +55,6 @@ void scheduler_dp_recalculate(struct scheduler_dp_data *dp_sch, bool is_ll_post_
 void dp_thread_fn(void *p1, void *p2, void *p3);
 unsigned int scheduler_dp_lock(uint16_t core);
 void scheduler_dp_unlock(unsigned int key);
-void scheduler_dp_grant(k_tid_t thread_id, uint16_t core);
 int scheduler_dp_task_init(struct task **task, const struct sof_uuid_entry *uid,
 			   const struct task_ops *ops, struct processing_module *mod,
 			   uint16_t core, size_t stack_size, uint32_t options);

src/schedule/zephyr_dp_schedule_application.c

@@ -505,7 +505,6 @@ int scheduler_dp_task_init(struct task **task, const struct sof_uuid_entry *uid,
 
 #if CONFIG_USERSPACE
 	k_thread_access_grant(pdata->thread_id, pdata->sem, &dp_sync[core]);
-	scheduler_dp_grant(pdata->thread_id, core);
 
 	unsigned int pidx;
 	size_t size;

src/schedule/zephyr_dp_schedule_thread.c

@@ -270,7 +270,6 @@ int scheduler_dp_task_init(struct task **task,
 					   CONFIG_DP_THREAD_PRIORITY, (*task)->flags, K_FOREVER);
 
 	k_thread_access_grant(pdata->thread_id, pdata->event);
-	scheduler_dp_grant(pdata->thread_id, cpu_get_id());
 
 	/* pin the thread to specific core */
 	ret = k_thread_cpu_pin(pdata->thread_id, core);