sched: add timer tasks and schedule_timeout()

include/socks/cpu.h

@@ -20,6 +20,7 @@ struct cpu_data {
 	unsigned int c_preempt_count;
 
 	struct runqueue c_rq;
+	struct queue c_timers;
 };
 
 /* maximum number of processor cores that the kernel can support.

include/socks/sched.h

@@ -41,6 +41,17 @@ enum sched_priority {
 	PRIO_REALTIME    = 24,
 };
 
+enum sched_mode {
+	/* used when calling from non-interrupt context.
+	   threads that aren't in state THREAD_READY are
+	   removed from the runqueue. */
+	SCHED_NORMAL     = 0,
+	/* used when calling from interrupt context.
+	   threads that aren't in state THREAD_READY are
+	   still added to the runqueue. */
+	SCHED_IRQ        = 1,
+};
+
 struct task {
 	struct task *t_parent;
 	unsigned int t_id;
@@ -82,8 +93,26 @@ struct runqueue {
 	struct thread *rq_cur, *rq_idle;
 };
 
+struct timer {
+	struct queue_entry t_entry;
+	struct cpu_data *t_cpu;
+	struct thread *t_owner;
+	unsigned long t_expiry;
+	void(*t_callback)(struct timer *);
+};
+
+struct wait_item {
+	struct thread *w_thread;
+	struct queue_entry w_entry;
+};
+
+struct waitqueue {
+	struct queue wq_waiters;
+	spin_lock_t wq_lock;
+};
+
 extern kern_status_t sched_init(void);
-extern void schedule(void);
+extern void schedule(enum sched_mode mode);
 extern void preempt_disable(void);
 extern void preempt_enable(void);
 
@@ -128,6 +157,11 @@ extern struct thread *thread_alloc(void);
 extern kern_status_t thread_init(struct thread *thr, uintptr_t ip);
 extern int thread_priority(struct thread *thr);
 
+extern void add_timer(struct timer *timer);
+extern void remove_timer(struct timer *timer);
+extern unsigned long schedule_timeout(unsigned long clock_ticks);
+extern unsigned long milli_sleep(unsigned long ms);
+
 #ifdef __cplusplus
 }
 #endif