linux/arch/microblaze/kernel/heartbeat.c
John Linn 6d858535be microblaze: Fix the heartbeat gpio to be more robust
The device tree handling for the gpio in the heart beat was not handling
the system when there was no gpio and it wasn't working with a newer version
of the gpio core which does not have the is-bidir property.

Signed-off-by: John Linn <john.linn@xilinx.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
2009-12-14 08:45:03 +01:00

73 lines
1.6 KiB
C

/*
* 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;
char *gpio_list[] = {
"xlnx,xps-gpio-1.00.a",
"xlnx,opb-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 = *(int *) 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);
}
}