/* * IDT Interprise 79RC32434 watchdog driver * * Copyright (C) 2006, Ondrej Zajicek * Copyright (C) 2008, Florian Fainelli * * based on * SoftDog 0.05: A Software Watchdog Device * * (c) Copyright 1996 Alan Cox , * All Rights Reserved. * * 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 /* For module specific items */ #include /* For new moduleparam's */ #include /* For standard types (like size_t) */ #include /* For the -ENODEV/... values */ #include /* For printk/panic/... */ #include /* For file operations */ #include /* For MODULE_ALIAS_MISCDEV (WATCHDOG_MINOR) */ #include /* For the watchdog specific items */ #include /* For __init/__exit/... */ #include /* For platform_driver framework */ #include /* For spin_lock/spin_unlock/... */ #include /* For copy_to_user/put_user/... */ #include /* For the Watchdog registers */ #define PFX KBUILD_MODNAME ": " #define VERSION "1.0" static struct { unsigned long inuse; spinlock_t io_lock; } rc32434_wdt_device; static struct integ __iomem *wdt_reg; static int expect_close; /* Board internal clock speed in Hz, * the watchdog timer ticks at. */ extern unsigned int idt_cpu_freq; /* translate wtcompare value to seconds and vice versa */ #define WTCOMP2SEC(x) (x / idt_cpu_freq) #define SEC2WTCOMP(x) (x * idt_cpu_freq) /* Use a default timeout of 20s. This should be * safe for CPU clock speeds up to 400MHz, as * ((2 ^ 32) - 1) / (400MHz / 2) = 21s. */ #define WATCHDOG_TIMEOUT 20 static int timeout = WATCHDOG_TIMEOUT; module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout value, in seconds (default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 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) ")"); /* apply or and nand masks to data read from addr and write back */ #define SET_BITS(addr, or, nand) \ writel((readl(&addr) | or) & ~nand, &addr) static int rc32434_wdt_set(int new_timeout) { int max_to = WTCOMP2SEC((u32)-1); if (new_timeout < 0 || new_timeout > max_to) { printk(KERN_ERR PFX "timeout value must be between 0 and %d", max_to); return -EINVAL; } timeout = new_timeout; spin_lock(&rc32434_wdt_device.io_lock); writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare); spin_unlock(&rc32434_wdt_device.io_lock); return 0; } static void rc32434_wdt_start(void) { u32 or, nand; spin_lock(&rc32434_wdt_device.io_lock); /* zero the counter before enabling */ writel(0, &wdt_reg->wtcount); /* don't generate a non-maskable interrupt, * do a warm reset instead */ nand = 1 << RC32434_ERR_WNE; or = 1 << RC32434_ERR_WRE; /* reset the ERRCS timeout bit in case it's set */ nand |= 1 << RC32434_ERR_WTO; SET_BITS(wdt_reg->errcs, or, nand); /* set the timeout (either default or based on module param) */ rc32434_wdt_set(timeout); /* reset WTC timeout bit and enable WDT */ nand = 1 << RC32434_WTC_TO; or = 1 << RC32434_WTC_EN; SET_BITS(wdt_reg->wtc, or, nand); spin_unlock(&rc32434_wdt_device.io_lock); printk(KERN_INFO PFX "Started watchdog timer.\n"); } static void rc32434_wdt_stop(void) { spin_lock(&rc32434_wdt_device.io_lock); /* Disable WDT */ SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN); spin_unlock(&rc32434_wdt_device.io_lock); printk(KERN_INFO PFX "Stopped watchdog timer.\n"); } static void rc32434_wdt_ping(void) { spin_lock(&rc32434_wdt_device.io_lock); writel(0, &wdt_reg->wtcount); spin_unlock(&rc32434_wdt_device.io_lock); } static int rc32434_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &rc32434_wdt_device.inuse)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); rc32434_wdt_start(); rc32434_wdt_ping(); return nonseekable_open(inode, file); } static int rc32434_wdt_release(struct inode *inode, struct file *file) { if (expect_close == 42) { rc32434_wdt_stop(); module_put(THIS_MODULE); } else { printk(KERN_CRIT PFX "device closed unexpectedly. WDT will not stop!\n"); rc32434_wdt_ping(); } clear_bit(0, &rc32434_wdt_device.inuse); return 0; } static ssize_t rc32434_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) { if (len) { if (!nowayout) { size_t i; /* In case it was set long ago */ expect_close = 0; for (i = 0; i != len; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') expect_close = 42; } } rc32434_wdt_ping(); return len; } return 0; } static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int new_timeout; unsigned int value; static const struct watchdog_info ident = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .identity = "RC32434_WDT Watchdog", }; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &ident, sizeof(ident))) return -EFAULT; break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: value = 0; if (copy_to_user(argp, &value, sizeof(int))) return -EFAULT; break; case WDIOC_SETOPTIONS: if (copy_from_user(&value, argp, sizeof(int))) return -EFAULT; switch (value) { case WDIOS_ENABLECARD: rc32434_wdt_start(); break; case WDIOS_DISABLECARD: rc32434_wdt_stop(); break; default: return -EINVAL; } break; case WDIOC_KEEPALIVE: rc32434_wdt_ping(); break; case WDIOC_SETTIMEOUT: if (copy_from_user(&new_timeout, argp, sizeof(int))) return -EFAULT; if (rc32434_wdt_set(new_timeout)) return -EINVAL; /* Fall through */ case WDIOC_GETTIMEOUT: return copy_to_user(argp, &timeout, sizeof(int)); default: return -ENOTTY; } return 0; } static const struct file_operations rc32434_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = rc32434_wdt_write, .unlocked_ioctl = rc32434_wdt_ioctl, .open = rc32434_wdt_open, .release = rc32434_wdt_release, }; static struct miscdevice rc32434_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &rc32434_wdt_fops, }; static char banner[] __devinitdata = KERN_INFO PFX "Watchdog Timer version " VERSION ", timer margin: %d sec\n"; static int __devinit rc32434_wdt_probe(struct platform_device *pdev) { int ret; struct resource *r; r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res"); if (!r) { printk(KERN_ERR PFX "failed to retrieve resources\n"); return -ENODEV; } wdt_reg = ioremap_nocache(r->start, resource_size(r)); if (!wdt_reg) { printk(KERN_ERR PFX "failed to remap I/O resources\n"); return -ENXIO; } spin_lock_init(&rc32434_wdt_device.io_lock); /* Make sure the watchdog is not running */ rc32434_wdt_stop(); /* Check that the heartbeat value is within it's range; * if not reset to the default */ if (rc32434_wdt_set(timeout)) { rc32434_wdt_set(WATCHDOG_TIMEOUT); printk(KERN_INFO PFX "timeout value must be between 0 and %d\n", WTCOMP2SEC((u32)-1)); } ret = misc_register(&rc32434_wdt_miscdev); if (ret < 0) { printk(KERN_ERR PFX "failed to register watchdog device\n"); goto unmap; } printk(banner, timeout); return 0; unmap: iounmap(wdt_reg); return ret; } static int __devexit rc32434_wdt_remove(struct platform_device *pdev) { misc_deregister(&rc32434_wdt_miscdev); iounmap(wdt_reg); return 0; } static void rc32434_wdt_shutdown(struct platform_device *pdev) { rc32434_wdt_stop(); } static struct platform_driver rc32434_wdt_driver = { .probe = rc32434_wdt_probe, .remove = __devexit_p(rc32434_wdt_remove), .shutdown = rc32434_wdt_shutdown, .driver = { .name = "rc32434_wdt", } }; static int __init rc32434_wdt_init(void) { return platform_driver_register(&rc32434_wdt_driver); } static void __exit rc32434_wdt_exit(void) { platform_driver_unregister(&rc32434_wdt_driver); } module_init(rc32434_wdt_init); module_exit(rc32434_wdt_exit); MODULE_AUTHOR("Ondrej Zajicek ," "Florian Fainelli "); MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);