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 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 setup_heartbeat(void) 46{ 47 struct device_node *gpio = NULL; 48 int *prop; 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 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); 66 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 } 72} 73