1/*
2 * Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
3 * Copyright (C) 2007-2009 PetaLogix
4 * Copyright (C) 2006 Atmark Techno, Inc.
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10
11#include <linux/sched.h>
12#include <linux/io.h>
13
14#include <asm/setup.h>
15#include <asm/page.h>
16#include <asm/prom.h>
17
18static unsigned int base_addr;
19
20void microblaze_heartbeat(void)
21{
22	static unsigned int cnt, period, dist;
23
24	if (base_addr) {
25		if (cnt == 0 || cnt == dist)
26			out_be32(base_addr, 1);
27		else if (cnt == 7 || cnt == dist + 7)
28			out_be32(base_addr, 0);
29
30		if (++cnt > period) {
31			cnt = 0;
32			/*
33			 * The hyperbolic function below modifies the heartbeat
34			 * period length in dependency of the current (5min)
35			 * load. It goes through the points f(0)=126, f(1)=86,
36			 * f(5)=51, f(inf)->30.
37			 */
38			period = ((672 << FSHIFT) / (5 * avenrun[0] +
39						(7 << FSHIFT))) + 30;
40			dist = period / 4;
41		}
42	}
43}
44
45void microblaze_setup_heartbeat(void)
46{
47	struct device_node *gpio = NULL;
48	int *prop;
49	int j;
50	const char * const gpio_list[] = {
51		"xlnx,xps-gpio-1.00.a",
52		NULL
53	};
54
55	for (j = 0; gpio_list[j] != NULL; j++) {
56		gpio = of_find_compatible_node(NULL, NULL, gpio_list[j]);
57		if (gpio)
58			break;
59	}
60
61	if (gpio) {
62		base_addr = be32_to_cpup(of_get_property(gpio, "reg", NULL));
63		base_addr = (unsigned long) ioremap(base_addr, PAGE_SIZE);
64		pr_notice("Heartbeat GPIO at 0x%x\n", base_addr);
65
66		/* GPIO is configured as output */
67		prop = (int *) of_get_property(gpio, "xlnx,is-bidir", NULL);
68		if (prop)
69			out_be32(base_addr + 4, 0);
70	}
71}
72