zephyr: ll-schedule: switch over to a simplified implementation

Switch SOF under Zephyr to use a simplified native low-latency
scheduler implementation.

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

Author: lyakh

src/include/sof/schedule/ll_schedule.h

@@ -34,11 +34,24 @@ struct ll_task_pdata {
 	uint16_t skip_cnt;	/**< how many times the task was skipped for execution */
 };
 
+#ifndef __ZEPHYR__
 int scheduler_init_ll(struct ll_schedule_domain *domain);
 
 int schedule_task_init_ll(struct task *task,
 			  const struct sof_uuid_entry *uid, uint16_t type,
 			  uint16_t priority, enum task_state (*run)(void *data),
 			  void *data, uint16_t core, uint32_t flags);
+#else
+int zephyr_ll_scheduler_init(struct ll_schedule_domain *domain);
+
+int zephyr_ll_task_init(struct task *task,
+			const struct sof_uuid_entry *uid, uint16_t type,
+			uint16_t priority, enum task_state (*run)(void *data),
+			void *data, uint16_t core, uint32_t flags);
+
+#define scheduler_init_ll zephyr_ll_scheduler_init
+#define schedule_task_init_ll zephyr_ll_task_init
+
+#endif
 
 #endif /* __SOF_SCHEDULE_LL_SCHEDULE_H__ */

src/include/sof/schedule/ll_schedule_domain.h

@@ -22,6 +22,8 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#define LL_TIMER_PERIOD_US 1000ULL /* default period in microseconds */
+
 struct dma;
 struct ll_schedule_domain;
 struct task;

src/schedule/zephyr_domain.c

@@ -34,7 +34,6 @@
 
 #define ZEPHYR_LL_STACK_SIZE	8192
 
-#define LL_TIMER_PERIOD_US 1000ULL /* period in microseconds */
 #define LL_TIMER_PERIOD_TICKS (CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC * LL_TIMER_PERIOD_US / 1000000ULL)
 
 K_KERNEL_STACK_ARRAY_DEFINE(ll_sched_stack, CONFIG_CORE_COUNT, ZEPHYR_LL_STACK_SIZE);