initial commit of lk (little kernel) project
diff --git a/kernel/timer.c b/kernel/timer.c
new file mode 100644
index 0000000..eb86e4a
--- /dev/null
+++ b/kernel/timer.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2008 Travis Geiselbrecht
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include <debug.h>
+#include <list.h>
+#include <kernel/thread.h>
+#include <kernel/timer.h>
+#include <platform/timer.h>
+#include <platform.h>
+
+static struct list_node timer_queue;
+
+void timer_initialize(timer_t *timer)
+{
+ timer->magic = TIMER_MAGIC;
+ list_clear_node(&timer->node);
+ timer->scheduled_time = 0;
+ timer->periodic_time = 0;
+ timer->callback = 0;
+ timer->arg = 0;
+}
+
+static void insert_timer_in_queue(timer_t *timer)
+{
+ timer_t *entry;
+
+ list_for_every_entry(&timer_queue, entry, timer_t, node) {
+ if (entry->scheduled_time > timer->scheduled_time) {
+ list_add_before(&entry->node, &timer->node);
+ return;
+ }
+ }
+
+ /* walked off the end of the list */
+ list_add_tail(&timer_queue, &timer->node);
+}
+
+void timer_set_oneshot(timer_t *timer, time_t delay, timer_callback callback, void *arg)
+{
+ time_t now;
+
+ DEBUG_ASSERT(timer->magic == TIMER_MAGIC);
+
+ if (list_in_list(&timer->node)) {
+ panic("timer %p already in list\n", timer);
+ }
+
+ now = current_time();
+ timer->scheduled_time = now + delay;
+ timer->periodic_time = 0;
+ timer->callback = callback;
+ timer->arg = arg;
+
+ enter_critical_section();
+
+ insert_timer_in_queue(timer);
+
+ exit_critical_section();
+}
+
+void timer_cancel(timer_t *timer)
+{
+ DEBUG_ASSERT(timer->magic == TIMER_MAGIC);
+
+ enter_critical_section();
+
+ if (list_in_list(&timer->node))
+ list_delete(&timer->node);
+
+ exit_critical_section();
+}
+
+/* called at interrupt time to process any pending timers */
+static enum handler_return timer_tick(void *arg, time_t now)
+{
+ timer_t *timer;
+ enum handler_return ret = INT_NO_RESCHEDULE;
+
+#if THREAD_STATS
+ thread_stats.timer_ints++;
+#endif
+
+ for (;;) {
+ /* see if there's an event to process */
+ timer = list_peek_head_type(&timer_queue, timer_t, node);
+ if (likely(!timer || now < timer->scheduled_time))
+ break;
+
+ /* process it */
+ DEBUG_ASSERT(timer->magic == TIMER_MAGIC);
+ list_delete(&timer->node);
+// timer = list_remove_head_type(&timer_queue, timer_t, node);
+// ASSERT(timer);
+
+#if THREAD_STATS
+ thread_stats.timers++;
+#endif
+
+ if (timer->callback(timer, now, timer->arg) == INT_RESCHEDULE)
+ ret = INT_RESCHEDULE;
+ }
+
+ /* let the scheduler have a shot to do quantum expiration, etc */
+ if (thread_timer_tick() == INT_RESCHEDULE)
+ ret = INT_RESCHEDULE;
+
+ return INT_RESCHEDULE;
+}
+
+void timer_init(void)
+{
+ list_initialize(&timer_queue);
+
+ /* register for a periodic timer tick */
+ platform_set_periodic_timer(timer_tick, NULL, 10); /* 10ms */
+}
+
+