New scheduler, with priorities for swcodec platforms. Frequent task

switching should be more efficient and tasks are stored in linked
lists to eliminate unnecessary task switching to improve performance.
Audio should no longer skip on swcodec targets caused by too CPU
hungry UI thread or background threads.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@10958 a1c6a512-1295-4272-9138-f99709370657

firmware/kernel.c

@@ -35,7 +35,6 @@ static void (*tick_funcs[MAX_NUM_TICK_TASKS])(void);
 static struct event_queue *all_queues[32];
 static int num_queues;
 
-void sleep(int ticks) ICODE_ATTR;
 void queue_wait(struct event_queue *q, struct event *ev) ICODE_ATTR;
 
 /****************************************************************************
@@ -71,13 +70,7 @@ void sleep(int ticks)
     } while(counter > 0);
 
 #else
-    /* Always sleep at least 1 tick */
-    int timeout = current_tick + ticks + 1;
-
-    while (TIME_BEFORE( current_tick, timeout )) {
-        sleep_thread();
-    }
-    wake_up_thread();
+    sleep_thread(ticks);
 #endif
 }
 
@@ -86,21 +79,24 @@ void yield(void)
 #if (CONFIG_CPU == S3C2440 || defined(ELIO_TPJ1022) && defined(BOOTLOADER))
     /* Some targets don't like yielding in the bootloader */
 #else
-    switch_thread();
-    wake_up_thread();
+    switch_thread(true, NULL);
 #endif
 }
 
 /****************************************************************************
  * Queue handling stuff
  ****************************************************************************/
-void queue_init(struct event_queue *q)
+void queue_init(struct event_queue *q, bool register_queue)
 {
     q->read = 0;
     q->write = 0;
-
-    /* Add it to the all_queues array */
-    all_queues[num_queues++] = q;
+    q->thread = NULL;
+    
+    if (register_queue)
+    {
+        /* Add it to the all_queues array */
+        all_queues[num_queues++] = q;
+    }
 }
 
 void queue_delete(struct event_queue *q)
@@ -108,6 +104,8 @@ void queue_delete(struct event_queue *q)
     int i;
     bool found = false;
 
+    wakeup_thread(&q->thread);
+    
     /* Find the queue to be deleted */
     for(i = 0;i < num_queues;i++)
     {
@@ -132,26 +130,22 @@ void queue_delete(struct event_queue *q)
 
 void queue_wait(struct event_queue *q, struct event *ev)
 {
-    while(q->read == q->write)
+    if (q->read == q->write)
     {
-        sleep_thread();
+        block_thread(&q->thread, 0);
     }
-    wake_up_thread();
 
     *ev = q->events[(q->read++) & QUEUE_LENGTH_MASK];
 }
 
 void queue_wait_w_tmo(struct event_queue *q, struct event *ev, int ticks)
 {
-    unsigned int timeout = current_tick + ticks;
-
-    while(q->read == q->write && TIME_BEFORE( current_tick, timeout ))
+    if (q->read == q->write && ticks > 0)
     {
-        sleep_thread();
+        block_thread(&q->thread, ticks);
     }
-    wake_up_thread();
 
-    if(q->read != q->write)
+    if (q->read != q->write)
     {
         *ev = q->events[(q->read++) & QUEUE_LENGTH_MASK];
     }
@@ -171,6 +165,9 @@ void queue_post(struct event_queue *q, long id, void *data)
 
     q->events[wr].id = id;
     q->events[wr].data = data;
+    
+    wakeup_thread(&q->thread);
+    
     set_irq_level(oldlevel);
 }
 
@@ -250,7 +247,6 @@ void IMIA0(void)
     }
 
     current_tick++;
-    wake_up_thread();
 
     TSR0 &= ~0x01;
 }
@@ -301,7 +297,6 @@ void TIMER0(void)
     }
 
     current_tick++;
-    wake_up_thread();
 
     TER0 = 0xff; /* Clear all events */
 }
@@ -330,7 +325,6 @@ void TIMER0(void)
     }
 
     current_tick++;
-    wake_up_thread();
 
     /* re-enable timer by clearing the counter */
     TACON |= 0x80;
@@ -382,7 +376,6 @@ void TIMER1(void)
     }
 
     current_tick++;
-    wake_up_thread();
 }
 #endif
 
@@ -415,7 +408,6 @@ void timer_handler(void)
     }
 
     current_tick++;
-    wake_up_thread();
 
     TIMERR0C = 1;
 }
@@ -513,22 +505,27 @@ int tick_remove_task(void (*f)(void))
 void mutex_init(struct mutex *m)
 {
     m->locked = false;
+    m->thread = NULL;
 }
 
 void mutex_lock(struct mutex *m)
 {
-    /* Wait until the lock is open... */
-    while(m->locked)
-        sleep_thread();
-    wake_up_thread();
-
+    if (m->locked)
+    {
+        /* Wait until the lock is open... */
+        block_thread(&m->thread, 0);
+    }
+    
     /* ...and lock it */
     m->locked = true;
 }
 
 void mutex_unlock(struct mutex *m)
 {
-    m->locked = false;
+    if (m->thread == NULL)
+        m->locked = false;
+    else
+        wakeup_thread(&m->thread);
 }
 
 #endif