From 6c0b462a2c43d8be50df627a2856d198ef76bf39 Mon Sep 17 00:00:00 2001
From: laforge <laforge@6dc7ffe9-61d6-0310-9af1-9938baff3ed1>
Date: Sun, 1 Oct 2006 19:23:15 +0000
Subject: - finish implementation of timers based on PIT - add [untested] code
 for timer-based LED blink codes

git-svn-id: https://svn.openpcd.org:2342/trunk@242 6dc7ffe9-61d6-0310-9af1-9938baff3ed1
---
 firmware/src/os/pit.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 86 insertions(+), 1 deletion(-)

(limited to 'firmware/src/os/pit.c')

diff --git a/firmware/src/os/pit.c b/firmware/src/os/pit.c
index 5726f06..5c096cc 100644
--- a/firmware/src/os/pit.c
+++ b/firmware/src/os/pit.c
@@ -15,20 +15,105 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  *
+ *
+ * TODO: handle jiffies wrap correctly!
  */
 
 #include <errno.h>
 #include <sys/types.h>
+#include <asm/system.h>
+
 #include <lib_AT91SAM7.h>
 #include <AT91SAM7.h>
+#include <os/pit.h>
+
 #include "../openpcd.h"
 
 /* PIT runs at MCK/16 (= 3MHz) */
 #define PIV_MS(x)		(x * 3000)
 
+static struct timer_list *timers;
+
+unsigned long jiffies;
+
+static void __timer_insert(struct timer_list *new)
+{
+	struct timer_list *tl, *tl_prev = NULL;
+
+	if (!timers) {
+		/* optimize for the common, fast case */
+		new->next = NULL;
+		timers = new;
+		return;
+	}
+
+	for (tl = timers; tl != NULL; tl = tl->next) {
+		if (tl->expires < new->expires) {
+			/* we need ot add just before this one */
+			if (!tl_prev) {
+				new->next = timers;
+				timers = new;
+			} else {
+				new->next = tl;
+				tl_prev->next = new;
+			}
+		}
+		tl_prev = tl;
+	}
+}
+
+static void __timer_remove(struct timer_list *old)
+{
+	struct timer_list *tl, *tl_prev = NULL;
+
+	for (tl = timers; tl != NULL; tl = tl->next) {
+		if (tl == old) {
+			if (tl == timers)
+				timers = tl->next;
+			else
+				tl_prev->next = tl->next;
+		}
+		tl_prev = tl;
+	}
+}
+
+int timer_del(struct timer_list *tl)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__timer_remove(tl);
+	local_irq_restore(flags);
+}
+
+void timer_add(struct timer_list *tl)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__timer_insert(tl);
+	local_irq_restore(flags);
+}
+
 static void pit_irq(void)
 {
-	/* FIXME: do something */	
+	struct timer_list *tl;
+	unsigned long flags;
+
+	jiffies++;
+
+	/* this is the most simple/stupid algorithm one can come up with, but
+	 * hey, we're on a small embedded platform with only a hand ful
+	 * of timers, at all */
+	for (tl = timers; tl != 0; tl = tl->next) {
+		if (tl->expires >= jiffies) {
+			tl->function(tl->data);
+			local_irq_save(flags);
+			/* delete timer from list */
+			__timer_remove(tl);
+			local_irq_restore(flags);
+		}
+	}
 }
 
 void pit_mdelay(u_int32_t ms)
-- 
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