| /* |
| * Watchdog timer for PowerPC Book-E systems |
| * |
| * Author: Matthew McClintock |
| * Maintainer: Kumar Gala <galak@kernel.crashing.org> |
| * |
| * Copyright 2005, 2008 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/smp.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; |
| 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 |
| |
| static DEFINE_SPINLOCK(booke_wdt_lock); |
| |
| static void __booke_wdt_ping(void *data) |
| { |
| mtspr(SPRN_TSR, TSR_ENW|TSR_WIS); |
| } |
| |
| static void booke_wdt_ping(void) |
| { |
| on_each_cpu(__booke_wdt_ping, NULL, 0, 0); |
| } |
| |
| static void __booke_wdt_enable(void *data) |
| { |
| u32 val; |
| |
| /* clear status before enabling watchdog */ |
| __booke_wdt_ping(NULL); |
| val = mfspr(SPRN_TCR); |
| val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period)); |
| |
| mtspr(SPRN_TCR, val); |
| } |
| |
| 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, |
| .identity = "PowerPC Book-E Watchdog", |
| }; |
| |
| 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; |
| } |
| |
| static int booke_wdt_open(struct inode *inode, struct file *file) |
| { |
| spin_lock(&booke_wdt_lock); |
| if (booke_wdt_enabled == 0) { |
| booke_wdt_enabled = 1; |
| on_each_cpu(__booke_wdt_enable, NULL, 0, 0); |
| printk(KERN_INFO "PowerPC Book-E Watchdog Timer Enabled " |
| "(wdt_period=%d)\n", booke_wdt_period); |
| } |
| spin_unlock(&booke_wdt_lock); |
| |
| 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); |
| } |
| |
| 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: %d\n", |
| WATCHDOG_MINOR, ret); |
| return ret; |
| } |
| |
| spin_lock(&booke_wdt_lock); |
| if (booke_wdt_enabled == 1) { |
| printk(KERN_INFO "PowerPC Book-E Watchdog Timer Enabled " |
| "(wdt_period=%d)\n", booke_wdt_period); |
| on_each_cpu(__booke_wdt_enable, NULL, 0, 0); |
| } |
| spin_unlock(&booke_wdt_lock); |
| |
| return ret; |
| } |
| device_initcall(booke_wdt_init); |