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ecc6dfc8 MS |
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 | ||
18 | static unsigned int base_addr; | |
19 | ||
20 | void 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 | ||
45 | void setup_heartbeat(void) | |
46 | { | |
47 | struct device_node *gpio = NULL; | |
6d858535 | 48 | int *prop; |
ecc6dfc8 MS |
49 | int j; |
50 | char *gpio_list[] = { | |
51 | "xlnx,xps-gpio-1.00.a", | |
52 | "xlnx,opb-gpio-1.00.a", | |
53 | NULL | |
54 | }; | |
55 | ||
56 | for (j = 0; gpio_list[j] != NULL; j++) { | |
57 | gpio = of_find_compatible_node(NULL, NULL, gpio_list[j]); | |
58 | if (gpio) | |
59 | break; | |
60 | } | |
61 | ||
6d858535 JL |
62 | if (gpio) { |
63 | base_addr = *(int *) of_get_property(gpio, "reg", NULL); | |
64 | base_addr = (unsigned long) ioremap(base_addr, PAGE_SIZE); | |
65 | printk(KERN_NOTICE "Heartbeat GPIO at 0x%x\n", base_addr); | |
ecc6dfc8 | 66 | |
6d858535 JL |
67 | /* GPIO is configured as output */ |
68 | prop = (int *) of_get_property(gpio, "xlnx,is-bidir", NULL); | |
69 | if (prop) | |
70 | out_be32(base_addr + 4, 0); | |
71 | } | |
ecc6dfc8 | 72 | } |