| /* |
| * Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu> |
| * Copyright (C) 2007-2009 PetaLogix |
| * 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 <linux/io.h> |
| |
| #include <asm/setup.h> |
| #include <asm/page.h> |
| #include <asm/prom.h> |
| |
| static unsigned int base_addr; |
| |
| void heartbeat(void) |
| { |
| static unsigned int cnt, period, dist; |
| |
| if (base_addr) { |
| if (cnt == 0 || cnt == dist) |
| out_be32(base_addr, 1); |
| else if (cnt == 7 || cnt == dist + 7) |
| out_be32(base_addr, 0); |
| |
| 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; |
| } |
| } |
| } |
| |
| void setup_heartbeat(void) |
| { |
| struct device_node *gpio = NULL; |
| int *prop; |
| int j; |
| const char * const gpio_list[] = { |
| "xlnx,xps-gpio-1.00.a", |
| NULL |
| }; |
| |
| for (j = 0; gpio_list[j] != NULL; j++) { |
| gpio = of_find_compatible_node(NULL, NULL, gpio_list[j]); |
| if (gpio) |
| break; |
| } |
| |
| if (gpio) { |
| base_addr = be32_to_cpup(of_get_property(gpio, "reg", NULL)); |
| base_addr = (unsigned long) ioremap(base_addr, PAGE_SIZE); |
| printk(KERN_NOTICE "Heartbeat GPIO at 0x%x\n", base_addr); |
| |
| /* GPIO is configured as output */ |
| prop = (int *) of_get_property(gpio, "xlnx,is-bidir", NULL); |
| if (prop) |
| out_be32(base_addr + 4, 0); |
| } |
| } |
