/* * 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; }