/* * drivers/watchdog/ubi32_wdt.c * Ubicom32 Watchdog Driver * * Originally based on softdog.c * Copyright 2006-2007 Analog Devices Inc. * Copyright 2006-2007 Michele d'Amico * Copyright 1996 Alan Cox * (C) Copyright 2009, Ubicom, Inc. * * This file is part of the Ubicom32 Linux Kernel Port. * * The Ubicom32 Linux Kernel Port 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. * * The Ubicom32 Linux Kernel Port is distributed in the hope that it * will be useful, but WITHOUT ANY WARRANTY; without even the implied * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See * the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with the Ubicom32 Linux Kernel Port. If not, * see . * * Ubicom32 implementation derived from (with many thanks): * arch/m68knommu * arch/blackfin * arch/parisc */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define WATCHDOG_NAME "ubi32-wdt" #define PFX WATCHDOG_NAME ": " #define OSC1_FREQ 12000000 #define WATCHDOG_SEC_TO_CYC(x) (OSC1_FREQ * (x)) #define WATCHDOG_MAX_SEC (0xffffffff / OSC1_FREQ) #define MIN_PROCESSOR_ADDRESS 0x03000000 static DEFINE_SPINLOCK(ubi32_wdt_spinlock); #define WATCHDOG_TIMEOUT 20 #if defined(CONFIG_WATCHDOG_NOWAYOUT) #define WATCHDOG_NOWAYOUT 1 #else #define WATCHDOG_NOWAYOUT 0 #endif static unsigned int timeout = WATCHDOG_TIMEOUT; static int nowayout = WATCHDOG_NOWAYOUT; static struct watchdog_info ubi32_wdt_info; static unsigned long open_check; static char expect_close; #if !defined(CONFIG_SMP) #define UBI32_WDT_LOCK(lock, flags) local_irq_save(flags) #define UBI32_WDT_UNLOCK(lock, flags) local_irq_restore(flags) #define UBI32_WDT_LOCK_CHECK() #else #define UBI32_WDT_LOCK(lock, flags) spin_lock_irqsave((lock), (flags)); #define UBI32_WDT_UNLOCK(lock, flags) spin_unlock_irqrestore((lock), (flags)); #define UBI32_WDT_LOCK_CHECK() BUG_ON(!spin_is_locked(&ubi32_wdt_spinlock)); #endif /* * ubi32_wdt_remaining() * Return the approximate number of seconds remaining */ static int ubi32_wdt_remaining(void) { int compare; int curr; UBI32_WDT_LOCK_CHECK(); ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL); compare = ubicom32_read_reg(&UBICOM32_IO_TIMER->wdcom); curr = ubicom32_read_reg(&UBICOM32_IO_TIMER->mptval); ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0); return (compare - curr) / OSC1_FREQ; } /* * ubi32_wdt_keepalive() * Keep the Userspace Watchdog Alive * * The Userspace watchdog got a KeepAlive: schedule the next timeout. */ static int ubi32_wdt_keepalive(void) { UBI32_WDT_LOCK_CHECK(); ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL); ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcom, ubicom32_read_reg(&UBICOM32_IO_TIMER->mptval) + WATCHDOG_SEC_TO_CYC(timeout)); ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0); return 0; } /* * ubi32_wdt_stop() * Stop the on-chip Watchdog */ static int ubi32_wdt_stop(void) { UBI32_WDT_LOCK_CHECK(); ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL); ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcfg, TIMER_WATCHDOG_DISABLE); ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0); return 0; } /* * ubi32_wdt_start() * Start the on-chip Watchdog */ static int ubi32_wdt_start(void) { UBI32_WDT_LOCK_CHECK(); ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL); ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcom, ubicom32_read_reg(&UBICOM32_IO_TIMER->mptval) + WATCHDOG_SEC_TO_CYC(timeout)); ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcfg, ~TIMER_WATCHDOG_DISABLE); ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0); return 0; } /* * ubi32_wdt_running() * Return true if the watchdog is configured */ static int ubi32_wdt_running(void) { int enabled; UBI32_WDT_LOCK_CHECK(); ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL); enabled = ubicom32_read_reg(&UBICOM32_IO_TIMER->wdcfg) == ~TIMER_WATCHDOG_DISABLE; ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0); return enabled; } /* * ubi32_wdt_set_timeout() * Set the Userspace Watchdog timeout * * - @t: new timeout value (in seconds) */ static int ubi32_wdt_set_timeout(unsigned long t) { UBI32_WDT_LOCK_CHECK(); if (t > WATCHDOG_MAX_SEC) { printk(KERN_WARNING PFX "request to large: %ld [1-%d] sec)\n", t, WATCHDOG_MAX_SEC); return -EINVAL; } /* * If we are running, then reset the time value so * that the new value has an immediate effect. */ timeout = t; if (ubi32_wdt_running()) { ubi32_wdt_keepalive(); } return 0; } /* * ubi32_wdt_open() * Open the Device */ static int ubi32_wdt_open(struct inode *inode, struct file *file) { unsigned long flags; if (test_and_set_bit(0, &open_check)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); spin_lock_irqsave(&ubi32_wdt_spinlock, flags); ubi32_wdt_start(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); return nonseekable_open(inode, file); } /* * ubi32_wdt_close() * Close the Device */ static int ubi32_wdt_release(struct inode *inode, struct file *file) { unsigned long flags; /* * If we don't expect a close, then the watchdog continues * even though the device is closed. The caller will have * a full timeout value to reopen the device and continue * stroking it. */ if (expect_close != 42) { printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); spin_lock_irqsave(&ubi32_wdt_spinlock, flags); ubi32_wdt_keepalive(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); } else { spin_lock_irqsave(&ubi32_wdt_spinlock, flags); ubi32_wdt_stop(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); } expect_close = 0; clear_bit(0, &open_check); return 0; } /* * ubi32_wdt_write() * Write to Device * * If the user writes nothing, nothing happens. * If the user writes a V, then we expect a close and allow a release. * If the user writes anything else, it is ignored. */ static ssize_t ubi32_wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { size_t i; unsigned long flags; /* * Every write resets the expect_close. The last write * must be a V to allow shutdown on close. */ expect_close = 0; /* * Empty writes still ping. */ if (!len) { goto ping; } /* * If nowayout is set, it does not matter if the caller * is trying to send the magic 'V' we will not allow a * close to stop us. */ if (nowayout) { goto ping; } /* * See if the program wrote a 'V' and if so disable * the watchdog on release. */ for (i = 0; i < len; i++) { char c; if (get_user(c, data + i)) { return -EFAULT; } if (c == 'V') { expect_close = 42; } } ping: spin_lock_irqsave(&ubi32_wdt_spinlock, flags); ubi32_wdt_keepalive(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); return len; } /* * ubi32_wdt_ioctl() * Query the watchdog device. * * Query basic information from the device or ping it, as outlined by the * watchdog API. */ static long ubi32_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &ubi32_wdt_info, sizeof(ubi32_wdt_info))) { return -EFAULT; } return 0; case WDIOC_GETSTATUS: { unsigned long flags; int running; spin_lock_irqsave(&ubi32_wdt_spinlock, flags); running = ubi32_wdt_running(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); return running; } case WDIOC_GETBOOTSTATUS: return ubicom32_get_reset_reason(); case WDIOC_SETOPTIONS: { unsigned long flags; int options, ret = -EINVAL; /* * The sample application does not pass a pointer * but directly passes a value of 1 or 2; however * all of the implementations (and thus probably * the real applications) pass a pointer to a value. * * It should be noted that WDIOC_SETOPTIONS is defined as * _IOR(WATCHDOG_IOCTL_BASE, 4, int), which means * that it should be an int and NOT a pointer. * * TODO: Examine this code for future chips. * TODO: Report the sample code defect. */ if ((int)p < MIN_PROCESSOR_ADDRESS) { options = (int)p; } else { if (get_user(options, p)) return -EFAULT; } spin_lock_irqsave(&ubi32_wdt_spinlock, flags); if (options & WDIOS_DISABLECARD) { ubi32_wdt_stop(); ret = 0; } if (options & WDIOS_ENABLECARD) { ubi32_wdt_start(); ret = 0; } spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); return ret; } case WDIOC_KEEPALIVE: { unsigned long flags; spin_lock_irqsave(&ubi32_wdt_spinlock, flags); ubi32_wdt_keepalive(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); return 0; } case WDIOC_SETTIMEOUT: { int new_timeout; unsigned long flags; int ret = 0; if (get_user(new_timeout, p)) return -EFAULT; spin_lock_irqsave(&ubi32_wdt_spinlock, flags); ret = ubi32_wdt_set_timeout(new_timeout); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); return ret; } case WDIOC_GETTIMEOUT: return put_user(timeout, p); case WDIOC_GETTIMELEFT: { unsigned long flags; int remaining = 0; spin_lock_irqsave(&ubi32_wdt_spinlock, flags); remaining = ubi32_wdt_remaining(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); return put_user(remaining, p); } default: return -ENOTTY; } } /* * ubi32_wdt_notify_sys() * Notification callback function for system events. * * Turn off the watchdog during a SYS_DOWN or SYS_HALT. */ static int ubi32_wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) { unsigned long flags; spin_lock_irqsave(&ubi32_wdt_spinlock, flags); ubi32_wdt_stop(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); } return NOTIFY_DONE; } #ifdef CONFIG_PM static int state_before_suspend; /* * ubi32_wdt_suspend() * suspend the watchdog * * Remember if the watchdog was running and stop it. */ static int ubi32_wdt_suspend(struct platform_device *pdev, pm_message_t state) { unsigned long flags; spin_lock_irqsave(&ubi32_wdt_spinlock, flags); state_before_suspend = ubi32_wdt_running(); ubi32_wdt_stop(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); return 0; } /* * ubi32_wdt_resume() * Resume the watchdog * * If the watchdog was running, turn it back on. */ static int ubi32_wdt_resume(struct platform_device *pdev) { if (state_before_suspend) { unsigned long flags; spin_lock_irqsave(&ubi32_wdt_spinlock, flags); ubi32_wdt_set_timeout(timeout); ubi32_wdt_start(); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); } return 0; } #else # define ubi32_wdt_suspend NULL # define ubi32_wdt_resume NULL #endif static const struct file_operations ubi32_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = ubi32_wdt_write, .unlocked_ioctl = ubi32_wdt_ioctl, .open = ubi32_wdt_open, .release = ubi32_wdt_release, }; static struct miscdevice ubi32_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &ubi32_wdt_fops, }; static struct watchdog_info ubi32_wdt_info = { .identity = "Ubicom32 Watchdog", .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; static struct notifier_block ubi32_wdt_notifier = { .notifier_call = ubi32_wdt_notify_sys, }; /* * ubi32_wdt_probe() * Probe/register the watchdog module * * Registers the misc device and notifier handler. Actual device * initialization is handled by ubi32_wdt_open(). */ static int __devinit ubi32_wdt_probe(struct platform_device *pdev) { int ret; ret = register_reboot_notifier(&ubi32_wdt_notifier); if (ret) { printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", ret); return ret; } ret = misc_register(&ubi32_wdt_miscdev); if (ret) { printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); unregister_reboot_notifier(&ubi32_wdt_notifier); return ret; } printk(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n", timeout, nowayout); return 0; } /* * ubi32_wdt_remove() * Uninstall the module * * Unregisters the misc device and notifier handler. Actual device * deinitialization is handled by ubi32_wdt_close(). */ static int __devexit ubi32_wdt_remove(struct platform_device *pdev) { misc_deregister(&ubi32_wdt_miscdev); unregister_reboot_notifier(&ubi32_wdt_notifier); return 0; } static struct platform_device *ubi32_wdt_device; static struct platform_driver ubi32_wdt_driver = { .probe = ubi32_wdt_probe, .remove = __devexit_p(ubi32_wdt_remove), .suspend = ubi32_wdt_suspend, .resume = ubi32_wdt_resume, .driver = { .name = WATCHDOG_NAME, .owner = THIS_MODULE, }, }; /* * ubi32_wdt_init() * Initialize the watchdog. * * Checks the module params and registers the platform device & driver. * Real work is in the platform probe function. */ static int __init ubi32_wdt_init(void) { unsigned long flags; int ret; /* * Check that the timeout value is within range */ spin_lock_irqsave(&ubi32_wdt_spinlock, flags); ret = ubi32_wdt_set_timeout(timeout); spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags); if (ret) { return ret; } /* * Since this is an on-chip device and needs no board-specific * resources, we'll handle all the platform device stuff here. */ ret = platform_driver_register(&ubi32_wdt_driver); if (ret) { printk(KERN_ERR PFX "unable to register driver\n"); return ret; } ubi32_wdt_device = platform_device_register_simple(WATCHDOG_NAME, -1, NULL, 0); if (IS_ERR(ubi32_wdt_device)) { printk(KERN_ERR PFX "unable to register device\n"); platform_driver_unregister(&ubi32_wdt_driver); return PTR_ERR(ubi32_wdt_device); } return 0; } /* * ubi32_wdt_exit() * Deinitialize module * * Back out the platform device & driver steps. Real work is in the * platform remove function. */ static void __exit ubi32_wdt_exit(void) { platform_device_unregister(ubi32_wdt_device); platform_driver_unregister(&ubi32_wdt_driver); } module_init(ubi32_wdt_init); module_exit(ubi32_wdt_exit); MODULE_AUTHOR("Sol Kavy"); MODULE_DESCRIPTION("Ubicom32 Watchdog Device Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");