From 7967a9ab13214543041e4408086668b4db8d3e62 Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Mon, 18 Apr 2022 21:10:57 +0300
Subject: start working on timer subsys

---
 common/timer.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 common/timer.c

(limited to 'common/timer.c')

diff --git a/common/timer.c b/common/timer.c
new file mode 100644
index 0000000..b48e455
--- /dev/null
+++ b/common/timer.c
@@ -0,0 +1,124 @@
+#include <apos/sp_tree.h>
+#include <apos/string.h>
+#include <apos/nodes.h>
+#include <apos/utils.h>
+#include <apos/timer.h>
+#include <arch/timer.h>
+#include <arch/cpu.h>
+
+static ticks_t ticks_per_sec = 0;
+static struct sp_root cpu_timers[MAX_CPUS] = {0};
+static struct node_root node_root;
+
+struct timer_node {
+	struct sp_node sp_n;
+	struct timer timer;
+};
+
+#define timer_container(ptr)\
+	container_of(ptr, struct timer_node, sp_n)
+
+#define timer_node_container(ptr)\
+	container_of(ptr, struct timer_node, timer)
+
+static struct sp_root *__cpu_timers()
+{
+	return &cpu_timers[cpu_id()];
+}
+
+void init_timer()
+{
+	ticks_per_sec = stat_timer();
+	init_nodes(&node_root, sizeof(struct timer_node));
+}
+
+static id_t __insert_timer(struct timer_node *ti)
+{
+	struct sp_root *root = __cpu_timers();
+	struct sp_node *n = sp_root(root), *p = NULL;
+	enum sp_dir d;
+	while (n) {
+		struct timer_node *t = container_of(n, struct timer_node, sp_n);
+		if (ti->timer.cid == t->timer.cid)
+			ti->timer.cid--;
+
+		p = n;
+
+		if (ti->timer.cid < t->timer.cid) {
+			n = sp_left(n);
+			d = LEFT;
+		} else {
+			n = sp_right(n);
+			d = RIGHT;
+		}
+	}
+	
+	if (sp_root(root))
+		sp_insert(&sp_root(root), p, &ti->sp_n, d);
+	else
+		sp_root(root) = &ti->sp_n;
+
+	return ti->timer.cid;
+}
+
+/* ticks is absolute */
+static id_t __new_timer(id_t tid, ticks_t ticks)
+{
+	struct timer_node *ti = (struct timer_node *)get_node(&node_root);
+	ti->timer.ticks = ticks;
+	ti->timer.cid = ticks;
+	ti->timer.tid = tid;
+	return __insert_timer(ti);
+}
+
+/* these are likely not perfectly accurate timers due to some random delay from
+ * function calls etc, but probably good enough. */
+id_t new_rel_timer(id_t tid, ticks_t ticks)
+{
+	return new_abs_timer(tid, ticks + current_ticks());
+}
+
+id_t new_abs_timer(id_t tid, ticks_t ticks)
+{
+	id_t id = __new_timer(tid, ticks);
+	set_timer(ticks);
+	return id;
+}
+
+struct timer *newest_timer()
+{
+	struct sp_node *t = sp_first(sp_root(__cpu_timers()));
+	return &timer_container(t)->timer;
+}
+
+struct timer *find_timer(id_t cid)
+{
+	struct sp_node *n = sp_root(__cpu_timers());
+	while (n) {
+		struct timer_node *t = timer_container(n);
+		if (t->timer.cid == cid)
+			return &t->timer;
+
+		if (t->timer.cid < cid)
+			n = sp_left(n);
+		else
+			n = sp_right(n);
+	}
+
+	return 0;
+}
+
+void remove_timer(struct timer *t)
+{
+	if (!t)
+		return;
+
+	struct sp_node *n = &timer_node_container(t)->sp_n;
+	sp_remove(&sp_root(__cpu_timers()), n);
+}
+
+/* TODO: does this overflow too early? */
+ticks_t nsecs_to_ticks(tunit_t nsecs)
+{
+	return (nsecs * ticks_per_sec) / 1000000000;
+}
-- 
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