1/* 2 * m8xx_wdt.c - MPC8xx watchdog driver 3 * 4 * Author: Florian Schirmer <jolt@tuxbox.org> 5 * 6 * 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under 7 * the terms of the GNU General Public License version 2. This program 8 * is licensed "as is" without any warranty of any kind, whether express 9 * or implied. 10 */ 11 12#include <linux/init.h> 13#include <linux/interrupt.h> 14#include <linux/irq.h> 15#include <linux/kernel.h> 16#include <linux/sched.h> 17#include <asm/io.h> 18#include <asm/8xx_immap.h> 19#include <syslib/m8xx_wdt.h> 20 21static int wdt_timeout; 22int m8xx_has_internal_rtc = 0; 23 24static irqreturn_t m8xx_wdt_interrupt(int, void *); 25static struct irqaction m8xx_wdt_irqaction = { 26 .handler = m8xx_wdt_interrupt, 27 .name = "watchdog", 28}; 29 30void m8xx_wdt_reset(void) 31{ 32 volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR; 33 34 out_be16(&imap->im_siu_conf.sc_swsr, 0x556c); /* write magic1 */ 35 out_be16(&imap->im_siu_conf.sc_swsr, 0xaa39); /* write magic2 */ 36} 37 38static irqreturn_t m8xx_wdt_interrupt(int irq, void *dev) 39{ 40 volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR; 41 42 m8xx_wdt_reset(); 43 44 setbits16(&imap->im_sit.sit_piscr, PISCR_PS); 45 return IRQ_HANDLED; 46} 47 48#define SYPCR_SWP 0x1 49#define SYPCR_SWE 0x4 50 51 52void __init m8xx_wdt_install_irq(volatile immap_t *imap, bd_t *binfo) 53{ 54 u32 pitc; 55 u32 pitrtclk; 56 57 /* 58 * Fire trigger if half of the wdt ticked down 59 */ 60 61 if (imap->im_sit.sit_rtcsc & RTCSC_38K) 62 pitrtclk = 9600; 63 else 64 pitrtclk = 8192; 65 66 if ((wdt_timeout) > (UINT_MAX / pitrtclk)) 67 pitc = wdt_timeout / binfo->bi_intfreq * pitrtclk / 2; 68 else 69 pitc = pitrtclk * wdt_timeout / binfo->bi_intfreq / 2; 70 71 out_be32(&imap->im_sit.sit_pitc, pitc << 16); 72 73 out_be16(&imap->im_sit.sit_piscr, (mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE); 74 75 if (setup_irq(PIT_INTERRUPT, &m8xx_wdt_irqaction)) 76 panic("m8xx_wdt: error setting up the watchdog irq!"); 77 78 printk(KERN_NOTICE 79 "m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc); 80 81} 82 83static void m8xx_wdt_timer_func(unsigned long data); 84 85static struct timer_list m8xx_wdt_timer = 86 TIMER_INITIALIZER(m8xx_wdt_timer_func, 0, 0); 87 88void m8xx_wdt_stop_timer(void) 89{ 90 del_timer(&m8xx_wdt_timer); 91} 92 93void m8xx_wdt_install_timer(void) 94{ 95 m8xx_wdt_timer.expires = jiffies + (HZ/2); 96 add_timer(&m8xx_wdt_timer); 97} 98 99static void m8xx_wdt_timer_func(unsigned long data) 100{ 101 m8xx_wdt_reset(); 102 m8xx_wdt_install_timer(); 103} 104 105void __init m8xx_wdt_handler_install(bd_t * binfo) 106{ 107 volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR; 108 u32 sypcr; 109 110 sypcr = in_be32(&imap->im_siu_conf.sc_sypcr); 111 112 if (!(sypcr & SYPCR_SWE)) { 113 printk(KERN_NOTICE "m8xx_wdt: wdt disabled (SYPCR: 0x%08X)\n", 114 sypcr); 115 return; 116 } 117 118 m8xx_wdt_reset(); 119 120 printk(KERN_NOTICE 121 "m8xx_wdt: active wdt found (SWTC: 0x%04X, SWP: 0x%01X)\n", 122 (sypcr >> 16), sypcr & SYPCR_SWP); 123 124 wdt_timeout = (sypcr >> 16) & 0xFFFF; 125 126 if (!wdt_timeout) 127 wdt_timeout = 0xFFFF; 128 129 if (sypcr & SYPCR_SWP) 130 wdt_timeout *= 2048; 131 132 m8xx_has_internal_rtc = in_be16(&imap->im_sit.sit_rtcsc) & RTCSC_RTE; 133 134 /* if the internal RTC is off use a kernel timer */ 135 if (!m8xx_has_internal_rtc) { 136 if (wdt_timeout < (binfo->bi_intfreq/HZ)) 137 printk(KERN_ERR "m8xx_wdt: timeout too short for ktimer!\n"); 138 m8xx_wdt_install_timer(); 139 } else 140 m8xx_wdt_install_irq(imap, binfo); 141 142 wdt_timeout /= binfo->bi_intfreq; 143} 144 145int m8xx_wdt_get_timeout(void) 146{ 147 return wdt_timeout; 148} 149