72 lines
1.6 KiB
C
72 lines
1.6 KiB
C
/*
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* Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2007-2009 PetaLogix
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* Copyright (C) 2006 Atmark Techno, Inc.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/sched.h>
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#include <linux/io.h>
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#include <asm/setup.h>
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#include <asm/page.h>
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#include <asm/prom.h>
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static unsigned int base_addr;
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void heartbeat(void)
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{
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static unsigned int cnt, period, dist;
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if (base_addr) {
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if (cnt == 0 || cnt == dist)
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out_be32(base_addr, 1);
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else if (cnt == 7 || cnt == dist + 7)
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out_be32(base_addr, 0);
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if (++cnt > period) {
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cnt = 0;
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/*
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* The hyperbolic function below modifies the heartbeat
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* period length in dependency of the current (5min)
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* load. It goes through the points f(0)=126, f(1)=86,
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* f(5)=51, f(inf)->30.
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*/
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period = ((672 << FSHIFT) / (5 * avenrun[0] +
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(7 << FSHIFT))) + 30;
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dist = period / 4;
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}
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}
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}
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void setup_heartbeat(void)
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{
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struct device_node *gpio = NULL;
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int *prop;
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int j;
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const char * const gpio_list[] = {
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"xlnx,xps-gpio-1.00.a",
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NULL
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};
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for (j = 0; gpio_list[j] != NULL; j++) {
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gpio = of_find_compatible_node(NULL, NULL, gpio_list[j]);
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if (gpio)
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break;
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}
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if (gpio) {
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base_addr = be32_to_cpup(of_get_property(gpio, "reg", NULL));
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base_addr = (unsigned long) ioremap(base_addr, PAGE_SIZE);
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pr_notice("Heartbeat GPIO at 0x%x\n", base_addr);
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/* GPIO is configured as output */
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prop = (int *) of_get_property(gpio, "xlnx,is-bidir", NULL);
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if (prop)
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out_be32(base_addr + 4, 0);
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}
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}
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