/* * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface * * Authors: Dave Updegraff <dave@cray.org> * Kumar Gala <galak@kernel.crashing.org> * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org> * ..and from sc520_wdt * Copyright (c) 2008 MontaVista Software, Inc. * Anton Vorontsov <avorontsov@ru.mvista.com> * * Note: it appears that you can only actually ENABLE or DISABLE the thing * once after POR. Once enabled, you cannot disable, and vice versa. * * 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/fs.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/timer.h> #include <linux/miscdevice.h> #include <linux/of_platform.h> #include <linux/module.h> #include <linux/watchdog.h> #include <linux/io.h> #include <linux/uaccess.h> #include <sysdev/fsl_soc.h> struct mpc8xxx_wdt { __be32 res0; __be32 swcrr; /* System watchdog control register */ #define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */ #define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */ #define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/ #define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */ __be32 swcnr; /* System watchdog count register */ u8 res1[2]; __be16 swsrr; /* System watchdog service register */ u8 res2[0xF0]; }; struct mpc8xxx_wdt_type { int prescaler; bool hw_enabled; }; static struct mpc8xxx_wdt __iomem *wd_base; static int mpc8xxx_wdt_init_late(void); static u16 timeout = 0xffff; module_param(timeout, ushort, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in ticks. (0<timeout<65536, default=65535"); static int reset = 1; module_param(reset, bool, 0); MODULE_PARM_DESC(reset, "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset"); static int nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); /* * We always prescale, but if someone really doesn't want to they can set this * to 0 */ static int prescale = 1; static unsigned int timeout_sec; static unsigned long wdt_is_open; static DEFINE_SPINLOCK(wdt_spinlock); static void mpc8xxx_wdt_keepalive(void) { /* Ping the WDT */ spin_lock(&wdt_spinlock); out_be16(&wd_base->swsrr, 0x556c); out_be16(&wd_base->swsrr, 0xaa39); spin_unlock(&wdt_spinlock); } static void mpc8xxx_wdt_timer_ping(unsigned long arg); static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, 0); static void mpc8xxx_wdt_timer_ping(unsigned long arg) { mpc8xxx_wdt_keepalive(); /* We're pinging it twice faster than needed, just to be sure. */ mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2); } static void mpc8xxx_wdt_pr_warn(const char *msg) { pr_crit("mpc8xxx_wdt: %s, expect the %s soon!\n", msg, reset ? "reset" : "machine check exception"); } static ssize_t mpc8xxx_wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { if (count) mpc8xxx_wdt_keepalive(); return count; } static int mpc8xxx_wdt_open(struct inode *inode, struct file *file) { u32 tmp = SWCRR_SWEN; if (test_and_set_bit(0, &wdt_is_open)) return -EBUSY; /* Once we start the watchdog we can't stop it */ if (nowayout) __module_get(THIS_MODULE); /* Good, fire up the show */ if (prescale) tmp |= SWCRR_SWPR; if (reset) tmp |= SWCRR_SWRI; tmp |= timeout << 16; out_be32(&wd_base->swcrr, tmp); del_timer_sync(&wdt_timer); return nonseekable_open(inode, file); } static int mpc8xxx_wdt_release(struct inode *inode, struct file *file) { if (!nowayout) mpc8xxx_wdt_timer_ping(0); else mpc8xxx_wdt_pr_warn("watchdog closed"); clear_bit(0, &wdt_is_open); return 0; } static long mpc8xxx_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; static struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING, .firmware_version = 1, .identity = "MPC8xxx", }; switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_KEEPALIVE: mpc8xxx_wdt_keepalive(); return 0; case WDIOC_GETTIMEOUT: return put_user(timeout_sec, p); default: return -ENOTTY; } } static const struct file_operations mpc8xxx_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = mpc8xxx_wdt_write, .unlocked_ioctl = mpc8xxx_wdt_ioctl, .open = mpc8xxx_wdt_open, .release = mpc8xxx_wdt_release, }; static struct miscdevice mpc8xxx_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &mpc8xxx_wdt_fops, }; static int __devinit mpc8xxx_wdt_probe(struct of_device *ofdev, const struct of_device_id *match) { int ret; struct device_node *np = ofdev->node; struct mpc8xxx_wdt_type *wdt_type = match->data; u32 freq = fsl_get_sys_freq(); bool enabled; if (!freq || freq == -1) return -EINVAL; wd_base = of_iomap(np, 0); if (!wd_base) return -ENOMEM; enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN; if (!enabled && wdt_type->hw_enabled) { pr_info("mpc8xxx_wdt: could not be enabled in software\n"); ret = -ENOSYS; goto err_unmap; } /* Calculate the timeout in seconds */ if (prescale) timeout_sec = (timeout * wdt_type->prescaler) / freq; else timeout_sec = timeout / freq; #ifdef MODULE ret = mpc8xxx_wdt_init_late(); if (ret) goto err_unmap; #endif pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d " "(%d seconds)\n", reset ? "reset" : "interrupt", timeout, timeout_sec); /* * If the watchdog was previously enabled or we're running on * MPC8xxx, we should ping the wdt from the kernel until the * userspace handles it. */ if (enabled) mpc8xxx_wdt_timer_ping(0); return 0; err_unmap: iounmap(wd_base); wd_base = NULL; return ret; } static int __devexit mpc8xxx_wdt_remove(struct of_device *ofdev) { mpc8xxx_wdt_pr_warn("watchdog removed"); del_timer_sync(&wdt_timer); misc_deregister(&mpc8xxx_wdt_miscdev); iounmap(wd_base); return 0; } static const struct of_device_id mpc8xxx_wdt_match[] = { { .compatible = "mpc83xx_wdt", .data = &(struct mpc8xxx_wdt_type) { .prescaler = 0x10000, }, }, { .compatible = "fsl,mpc8610-wdt", .data = &(struct mpc8xxx_wdt_type) { .prescaler = 0x10000, .hw_enabled = true, }, }, { .compatible = "fsl,mpc823-wdt", .data = &(struct mpc8xxx_wdt_type) { .prescaler = 0x800, }, }, {}, }; MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match); static struct of_platform_driver mpc8xxx_wdt_driver = { .match_table = mpc8xxx_wdt_match, .probe = mpc8xxx_wdt_probe, .remove = __devexit_p(mpc8xxx_wdt_remove), .driver = { .name = "mpc8xxx_wdt", .owner = THIS_MODULE, }, }; /* * We do wdt initialization in two steps: arch_initcall probes the wdt * very early to start pinging the watchdog (misc devices are not yet * available), and later module_init() just registers the misc device. */ static int mpc8xxx_wdt_init_late(void) { int ret; if (!wd_base) return -ENODEV; ret = misc_register(&mpc8xxx_wdt_miscdev); if (ret) { pr_err("cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); return ret; } return 0; } #ifndef MODULE module_init(mpc8xxx_wdt_init_late); #endif static int __init mpc8xxx_wdt_init(void) { return of_register_platform_driver(&mpc8xxx_wdt_driver); } arch_initcall(mpc8xxx_wdt_init); static void __exit mpc8xxx_wdt_exit(void) { of_unregister_platform_driver(&mpc8xxx_wdt_driver); } module_exit(mpc8xxx_wdt_exit); MODULE_AUTHOR("Dave Updegraff, Kumar Gala"); MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx " "uProcessors"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);