1/*
2 * arch/sh64/kernel/led.c
3 *
4 * Copyright (C) 2002 Stuart Menefy <stuart.menefy@st.com>
5 *
6 * May be copied or modified under the terms of the GNU General Public
7 * License.  See linux/COPYING for more information.
8 *
9 * Flash the LEDs
10 */
11#include <linux/stddef.h>
12#include <linux/sched.h>
13
14void mach_led(int pos, int val);
15
16/* acts like an actual heart beat -- ie thump-thump-pause... */
17void heartbeat(void)
18{
19	static unsigned int cnt = 0, period = 0, dist = 0;
20
21	if (cnt == 0 || cnt == dist) {
22		mach_led(-1, 1);
23	} else if (cnt == 7 || cnt == dist + 7) {
24		mach_led(-1, 0);
25	}
26
27	if (++cnt > period) {
28		cnt = 0;
29
30		/*
31		 * The hyperbolic function below modifies the heartbeat period
32		 * length in dependency of the current (5min) load. It goes
33		 * through the points f(0)=126, f(1)=86, f(5)=51, f(inf)->30.
34		 */
35		period = ((672 << FSHIFT) / (5 * avenrun[0] +
36					    (7 << FSHIFT))) + 30;
37		dist = period / 4;
38	}
39}
40