150 lines
3.4 KiB
C
150 lines
3.4 KiB
C
/*
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* m8xx_wdt.c - MPC8xx watchdog driver
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*
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* Author: Florian Schirmer <jolt@tuxbox.org>
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*
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* 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
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* the terms of the GNU General Public License version 2. This program
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* is licensed "as is" without any warranty of any kind, whether express
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* or implied.
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*/
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <asm/io.h>
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#include <asm/8xx_immap.h>
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#include <syslib/m8xx_wdt.h>
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static int wdt_timeout;
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int m8xx_has_internal_rtc = 0;
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static irqreturn_t m8xx_wdt_interrupt(int, void *, struct pt_regs *);
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static struct irqaction m8xx_wdt_irqaction = {
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.handler = m8xx_wdt_interrupt,
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.name = "watchdog",
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};
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void m8xx_wdt_reset(void)
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{
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volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
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out_be16(&imap->im_siu_conf.sc_swsr, 0x556c); /* write magic1 */
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out_be16(&imap->im_siu_conf.sc_swsr, 0xaa39); /* write magic2 */
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}
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static irqreturn_t m8xx_wdt_interrupt(int irq, void *dev, struct pt_regs *regs)
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{
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volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
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m8xx_wdt_reset();
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out_be16(&imap->im_sit.sit_piscr, in_be16(&imap->im_sit.sit_piscr) | PISCR_PS); /* clear irq */
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return IRQ_HANDLED;
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}
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#define SYPCR_SWP 0x1
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#define SYPCR_SWE 0x4
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void __init m8xx_wdt_install_irq(volatile immap_t *imap, bd_t *binfo)
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{
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u32 pitc;
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u32 pitrtclk;
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/*
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* Fire trigger if half of the wdt ticked down
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*/
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if (imap->im_sit.sit_rtcsc & RTCSC_38K)
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pitrtclk = 9600;
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else
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pitrtclk = 8192;
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if ((wdt_timeout) > (UINT_MAX / pitrtclk))
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pitc = wdt_timeout / binfo->bi_intfreq * pitrtclk / 2;
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else
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pitc = pitrtclk * wdt_timeout / binfo->bi_intfreq / 2;
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out_be32(&imap->im_sit.sit_pitc, pitc << 16);
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out_be16(&imap->im_sit.sit_piscr, (mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE);
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if (setup_irq(PIT_INTERRUPT, &m8xx_wdt_irqaction))
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panic("m8xx_wdt: error setting up the watchdog irq!");
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printk(KERN_NOTICE
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"m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc);
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}
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static void m8xx_wdt_timer_func(unsigned long data);
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static struct timer_list m8xx_wdt_timer =
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TIMER_INITIALIZER(m8xx_wdt_timer_func, 0, 0);
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void m8xx_wdt_stop_timer(void)
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{
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del_timer(&m8xx_wdt_timer);
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}
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void m8xx_wdt_install_timer(void)
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{
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m8xx_wdt_timer.expires = jiffies + (HZ/2);
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add_timer(&m8xx_wdt_timer);
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}
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static void m8xx_wdt_timer_func(unsigned long data)
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{
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m8xx_wdt_reset();
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m8xx_wdt_install_timer();
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}
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void __init m8xx_wdt_handler_install(bd_t * binfo)
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{
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volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
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u32 sypcr;
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sypcr = in_be32(&imap->im_siu_conf.sc_sypcr);
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if (!(sypcr & SYPCR_SWE)) {
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printk(KERN_NOTICE "m8xx_wdt: wdt disabled (SYPCR: 0x%08X)\n",
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sypcr);
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return;
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}
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m8xx_wdt_reset();
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printk(KERN_NOTICE
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"m8xx_wdt: active wdt found (SWTC: 0x%04X, SWP: 0x%01X)\n",
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(sypcr >> 16), sypcr & SYPCR_SWP);
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wdt_timeout = (sypcr >> 16) & 0xFFFF;
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if (!wdt_timeout)
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wdt_timeout = 0xFFFF;
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if (sypcr & SYPCR_SWP)
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wdt_timeout *= 2048;
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m8xx_has_internal_rtc = in_be16(&imap->im_sit.sit_rtcsc) & RTCSC_RTE;
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/* if the internal RTC is off use a kernel timer */
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if (!m8xx_has_internal_rtc) {
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if (wdt_timeout < (binfo->bi_intfreq/HZ))
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printk(KERN_ERR "m8xx_wdt: timeout too short for ktimer!\n");
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m8xx_wdt_install_timer();
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} else
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m8xx_wdt_install_irq(imap, binfo);
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wdt_timeout /= binfo->bi_intfreq;
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}
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int m8xx_wdt_get_timeout(void)
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{
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return wdt_timeout;
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}
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