[PATCH 21/58] microblaze_v5: heartbeat file

[monstr]

From: Michal Simek <monstr@xxxxxxxxx>

Acked-by: Stephen Neuendorffer <stephen.neuendorffer@xxxxxxxxxx>
Signed-off-by: Michal Simek <monstr@xxxxxxxxx>
---
 arch/microblaze/kernel/heartbeat.c |   35 +++++++++++++++++++++++++++++++++++
 1 files changed, 35 insertions(+), 0 deletions(-)
 create mode 100644 arch/microblaze/kernel/heartbeat.c

diff --git a/arch/microblaze/kernel/heartbeat.c b/arch/microblaze/kernel/heartbeat.c
new file mode 100644
index 0000000..5a21c1d
--- /dev/null
+++ b/arch/microblaze/kernel/heartbeat.c
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2007-2008 Michal Simek <monstr@xxxxxxxxx>
+ * Copyright (C) 2006 Atmark Techno, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/sched.h>
+#include <asm/page.h>
+#include <asm/io.h>
+#include <asm/setup.h>
+
+void heartbeat(void)
+{
+	static unsigned int cnt, period, dist;
+
+	if (cnt == 0 || cnt == dist)
+		iowrite32(1, CONFIG_HEART_BEAT_ADDRESS);
+	else if (cnt == 7 || cnt == dist + 7)
+		iowrite32(0, CONFIG_HEART_BEAT_ADDRESS);
+
+	if (++cnt > period) {
+		cnt = 0;
+		/*
+		 * The hyperbolic function below modifies the heartbeat period
+		 * length in dependency of the current (5min) load. It goes
+		 * through the points f(0)=126, f(1)=86, f(5)=51, f(inf)->30.
+		 */
+		period = ((672 << FSHIFT) / (5 * avenrun[0] +
+					(7 << FSHIFT))) + 30;
+		dist = period / 4;
+	}
+}
-- 
1.5.4.GIT

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