/* * 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/irq.h> #include <linux/kernel.h> #include <linux/sched.h> #include <asm/io.h> #include <asm/8xx_immap.h> #include <syslib/m8xx_wdt.h> static int wdt_timeout; int m8xx_has_internal_rtc = 0; static irqreturn_t m8xx_wdt_interrupt(int, void *, struct pt_regs *); static struct irqaction m8xx_wdt_irqaction = { .handler = m8xx_wdt_interrupt, .name = "watchdog", }; void m8xx_wdt_reset(void) { volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR; out_be16(&imap->im_siu_conf.sc_swsr, 0x556c); /* write magic1 */ out_be16(&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(); setbits16(&imap->im_sit.sit_piscr, PISCR_PS); return IRQ_HANDLED; } #define SYPCR_SWP 0x1 #define SYPCR_SWE 0x4 void __init m8xx_wdt_install_irq(volatile immap_t *imap, bd_t *binfo) { u32 pitc; u32 pitrtclk; /* * 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; out_be32(&imap->im_sit.sit_pitc, pitc << 16); out_be16(&imap->im_sit.sit_piscr, (mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE); if (setup_irq(PIT_INTERRUPT, &m8xx_wdt_irqaction)) panic("m8xx_wdt: error setting up the watchdog irq!"); printk(KERN_NOTICE "m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc); } static void m8xx_wdt_timer_func(unsigned long data); static struct timer_list m8xx_wdt_timer = TIMER_INITIALIZER(m8xx_wdt_timer_func, 0, 0); void m8xx_wdt_stop_timer(void) { del_timer(&m8xx_wdt_timer); } void m8xx_wdt_install_timer(void) { m8xx_wdt_timer.expires = jiffies + (HZ/2); add_timer(&m8xx_wdt_timer); } static void m8xx_wdt_timer_func(unsigned long data) { m8xx_wdt_reset(); m8xx_wdt_install_timer(); } void __init m8xx_wdt_handler_install(bd_t * binfo) { volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR; u32 sypcr; sypcr = in_be32(&imap->im_siu_conf.sc_sypcr); if (!(sypcr & SYPCR_SWE)) { 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 & SYPCR_SWP); wdt_timeout = (sypcr >> 16) & 0xFFFF; if (!wdt_timeout) wdt_timeout = 0xFFFF; if (sypcr & SYPCR_SWP) wdt_timeout *= 2048; m8xx_has_internal_rtc = in_be16(&imap->im_sit.sit_rtcsc) & RTCSC_RTE; /* if the internal RTC is off use a kernel timer */ if (!m8xx_has_internal_rtc) { if (wdt_timeout < (binfo->bi_intfreq/HZ)) printk(KERN_ERR "m8xx_wdt: timeout too short for ktimer!\n"); m8xx_wdt_install_timer(); } else m8xx_wdt_install_irq(imap, binfo); wdt_timeout /= binfo->bi_intfreq; } int m8xx_wdt_get_timeout(void) { return wdt_timeout; }