/* * drivers/char/watchdog/booke_wdt.c * * Watchdog timer for PowerPC Book-E systems * * Author: Matthew McClintock * Maintainer: Kumar Gala <galak@kernel.crashing.org> * * Copyright 2005 Freescale Semiconductor Inc. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. */ #include <linux/module.h> #include <linux/fs.h> #include <linux/miscdevice.h> #include <linux/notifier.h> #include <linux/watchdog.h> #include <asm/reg_booke.h> #include <asm/uaccess.h> #include <asm/system.h> /* If the kernel parameter wdt=1, the watchdog will be enabled at boot. * Also, the wdt_period sets the watchdog timer period timeout. * For E500 cpus the wdt_period sets which bit changing from 0->1 will * trigger a watchog timeout. This watchdog timeout will occur 3 times, the * first time nothing will happen, the second time a watchdog exception will * occur, and the final time the board will reset. */ #ifdef CONFIG_FSL_BOOKE #define WDT_PERIOD_DEFAULT 63 /* Ex. wdt_period=28 bus=333Mhz , reset=~40sec */ #else #define WDT_PERIOD_DEFAULT 3 /* Refer to the PPC40x and PPC4xx manuals */ #endif /* for timing information */ u32 booke_wdt_enabled = 0; u32 booke_wdt_period = WDT_PERIOD_DEFAULT; #ifdef CONFIG_FSL_BOOKE #define WDTP(x) ((((63-x)&0x3)<<30)|(((63-x)&0x3c)<<15)) #else #define WDTP(x) (TCR_WP(x)) #endif /* * booke_wdt_ping: */ static __inline__ void booke_wdt_ping(void) { mtspr(SPRN_TSR, TSR_ENW|TSR_WIS); } /* * booke_wdt_enable: */ static __inline__ void booke_wdt_enable(void) { u32 val; /* clear status before enabling watchdog */ booke_wdt_ping(); val = mfspr(SPRN_TCR); val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period)); mtspr(SPRN_TCR, val); } /* * booke_wdt_write: */ static ssize_t booke_wdt_write (struct file *file, const char __user *buf, size_t count, loff_t *ppos) { booke_wdt_ping(); return count; } static struct watchdog_info ident = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, .firmware_version = 0, .identity = "PowerPC Book-E Watchdog", }; /* * booke_wdt_ioctl: */ static int booke_wdt_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { u32 tmp = 0; u32 __user *p = (u32 __user *)arg; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user ((struct watchdog_info __user *) arg, &ident, sizeof(struct watchdog_info))) return -EFAULT; case WDIOC_GETSTATUS: return put_user(ident.options, p); case WDIOC_GETBOOTSTATUS: /* XXX: something is clearing TSR */ tmp = mfspr(SPRN_TSR) & TSR_WRS(3); /* returns 1 if last reset was caused by the WDT */ return (tmp ? 1 : 0); case WDIOC_KEEPALIVE: booke_wdt_ping(); return 0; case WDIOC_SETTIMEOUT: if (get_user(booke_wdt_period, p)) return -EFAULT; mtspr(SPRN_TCR, (mfspr(SPRN_TCR)&~WDTP(0))|WDTP(booke_wdt_period)); return 0; case WDIOC_GETTIMEOUT: return put_user(booke_wdt_period, p); case WDIOC_SETOPTIONS: if (get_user(tmp, p)) return -EINVAL; if (tmp == WDIOS_ENABLECARD) { booke_wdt_ping(); break; } else return -EINVAL; return 0; default: return -ENOTTY; } return 0; } /* * booke_wdt_open: */ static int booke_wdt_open (struct inode *inode, struct file *file) { if (booke_wdt_enabled == 0) { booke_wdt_enabled = 1; booke_wdt_enable(); printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n", booke_wdt_period); } return nonseekable_open(inode, file); } static const struct file_operations booke_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = booke_wdt_write, .ioctl = booke_wdt_ioctl, .open = booke_wdt_open, }; static struct miscdevice booke_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &booke_wdt_fops, }; static void __exit booke_wdt_exit(void) { misc_deregister(&booke_wdt_miscdev); } /* * booke_wdt_init: */ static int __init booke_wdt_init(void) { int ret = 0; printk (KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n"); ident.firmware_version = cur_cpu_spec->pvr_value; ret = misc_register(&booke_wdt_miscdev); if (ret) { printk (KERN_CRIT "Cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); return ret; } if (booke_wdt_enabled == 1) { printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n", booke_wdt_period); booke_wdt_enable(); } return ret; } device_initcall(booke_wdt_init);