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/*
* m8xx_wdt.c - MPC8xx watchdog driver
*
* Author: Florian Schirmer <jolt@tuxbox.org>
*
* 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <asm/8xx_immap.h>
#include <syslib/m8xx_wdt.h>
static int wdt_timeout;
void m8xx_wdt_reset(void)
{
volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
imap->im_siu_conf.sc_swsr = 0x556c; /* write magic1 */
imap->im_siu_conf.sc_swsr = 0xaa39; /* write magic2 */
}
static irqreturn_t m8xx_wdt_interrupt(int irq, void *dev, struct pt_regs *regs)
{
volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
m8xx_wdt_reset();
imap->im_sit.sit_piscr |= PISCR_PS; /* clear irq */
return IRQ_HANDLED;
}
void __init m8xx_wdt_handler_install(bd_t * binfo)
{
volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
u32 pitc;
u32 sypcr;
u32 pitrtclk;
sypcr = imap->im_siu_conf.sc_sypcr;
if (!(sypcr & 0x04)) {
printk(KERN_NOTICE "m8xx_wdt: wdt disabled (SYPCR: 0x%08X)\n",
sypcr);
return;
}
m8xx_wdt_reset();
printk(KERN_NOTICE
"m8xx_wdt: active wdt found (SWTC: 0x%04X, SWP: 0x%01X)\n",
(sypcr >> 16), sypcr & 0x01);
wdt_timeout = (sypcr >> 16) & 0xFFFF;
if (!wdt_timeout)
wdt_timeout = 0xFFFF;
if (sypcr & 0x01)
wdt_timeout *= 2048;
/*
* Fire trigger if half of the wdt ticked down
*/
if (imap->im_sit.sit_rtcsc & RTCSC_38K)
pitrtclk = 9600;
else
pitrtclk = 8192;
if ((wdt_timeout) > (UINT_MAX / pitrtclk))
pitc = wdt_timeout / binfo->bi_intfreq * pitrtclk / 2;
else
pitc = pitrtclk * wdt_timeout / binfo->bi_intfreq / 2;
imap->im_sit.sit_pitc = pitc << 16;
imap->im_sit.sit_piscr =
(mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE;
if (request_irq(PIT_INTERRUPT, m8xx_wdt_interrupt, 0, "watchdog", NULL))
panic("m8xx_wdt: could not allocate watchdog irq!");
printk(KERN_NOTICE
"m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc);
wdt_timeout /= binfo->bi_intfreq;
}
int m8xx_wdt_get_timeout(void)
{
return wdt_timeout;
}
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