/* * Watchdog driver for Kendin/Micrel KS8695. * * (C) 2007 Andrew Victor * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/bitops.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/miscdevice.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/platform_device.h> #include <linux/types.h> #include <linux/watchdog.h> #include <linux/io.h> #include <linux/uaccess.h> #include <mach/hardware.h> #define KS8695_TMR_OFFSET (0xF0000 + 0xE400) #define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET) /* * Timer registers */ #define KS8695_TMCON (0x00) /* Timer Control Register */ #define KS8695_T0TC (0x08) /* Timer 0 Timeout Count Register */ #define TMCON_T0EN (1 << 0) /* Timer 0 Enable */ /* Timer0 Timeout Counter Register */ #define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */ #define WDT_DEFAULT_TIME 5 /* seconds */ #define WDT_MAX_TIME 171 /* seconds */ static int wdt_time = WDT_DEFAULT_TIME; static bool nowayout = WATCHDOG_NOWAYOUT; module_param(wdt_time, int, 0); MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" __MODULE_STRING(WDT_DEFAULT_TIME) ")"); #ifdef CONFIG_WATCHDOG_NOWAYOUT module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); #endif static unsigned long ks8695wdt_busy; static DEFINE_SPINLOCK(ks8695_lock); /* ......................................................................... */ /* * Disable the watchdog. */ static inline void ks8695_wdt_stop(void) { unsigned long tmcon; spin_lock(&ks8695_lock); /* disable timer0 */ tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); spin_unlock(&ks8695_lock); } /* * Enable and reset the watchdog. */ static inline void ks8695_wdt_start(void) { unsigned long tmcon; unsigned long tval = wdt_time * KS8695_CLOCK_RATE; spin_lock(&ks8695_lock); /* disable timer0 */ tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); /* program timer0 */ __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC); /* re-enable timer0 */ tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); spin_unlock(&ks8695_lock); } /* * Reload the watchdog timer. (ie, pat the watchdog) */ static inline void ks8695_wdt_reload(void) { unsigned long tmcon; spin_lock(&ks8695_lock); /* disable, then re-enable timer0 */ tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); spin_unlock(&ks8695_lock); } /* * Change the watchdog time interval. */ static int ks8695_wdt_settimeout(int new_time) { /* * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz * * Since WDV is a 16-bit counter, the maximum period is * 65536 / 0.256 = 256 seconds. */ if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) return -EINVAL; /* Set new watchdog time. It will be used when ks8695_wdt_start() is called. */ wdt_time = new_time; return 0; } /* ......................................................................... */ /* * Watchdog device is opened, and watchdog starts running. */ static int ks8695_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &ks8695wdt_busy)) return -EBUSY; ks8695_wdt_start(); return nonseekable_open(inode, file); } /* * Close the watchdog device. * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also * disabled. */ static int ks8695_wdt_close(struct inode *inode, struct file *file) { /* Disable the watchdog when file is closed */ if (!nowayout) ks8695_wdt_stop(); clear_bit(0, &ks8695wdt_busy); return 0; } static const struct watchdog_info ks8695_wdt_info = { .identity = "ks8695 watchdog", .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, }; /* * Handle commands from user-space. */ static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; int new_value; switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user(argp, &ks8695_wdt_info, sizeof(ks8695_wdt_info)) ? -EFAULT : 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_SETOPTIONS: if (get_user(new_value, p)) return -EFAULT; if (new_value & WDIOS_DISABLECARD) ks8695_wdt_stop(); if (new_value & WDIOS_ENABLECARD) ks8695_wdt_start(); return 0; case WDIOC_KEEPALIVE: ks8695_wdt_reload(); /* pat the watchdog */ return 0; case WDIOC_SETTIMEOUT: if (get_user(new_value, p)) return -EFAULT; if (ks8695_wdt_settimeout(new_value)) return -EINVAL; /* Enable new time value */ ks8695_wdt_start(); /* Return current value */ return put_user(wdt_time, p); case WDIOC_GETTIMEOUT: return put_user(wdt_time, p); default: return -ENOTTY; } } /* * Pat the watchdog whenever device is written to. */ static ssize_t ks8695_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) { ks8695_wdt_reload(); /* pat the watchdog */ return len; } /* ......................................................................... */ static const struct file_operations ks8695wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .unlocked_ioctl = ks8695_wdt_ioctl, .open = ks8695_wdt_open, .release = ks8695_wdt_close, .write = ks8695_wdt_write, }; static struct miscdevice ks8695wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &ks8695wdt_fops, }; static int ks8695wdt_probe(struct platform_device *pdev) { int res; if (ks8695wdt_miscdev.parent) return -EBUSY; ks8695wdt_miscdev.parent = &pdev->dev; res = misc_register(&ks8695wdt_miscdev); if (res) return res; pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n", wdt_time, nowayout ? ", nowayout" : ""); return 0; } static int ks8695wdt_remove(struct platform_device *pdev) { misc_deregister(&ks8695wdt_miscdev); ks8695wdt_miscdev.parent = NULL; return 0; } static void ks8695wdt_shutdown(struct platform_device *pdev) { ks8695_wdt_stop(); } #ifdef CONFIG_PM static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message) { ks8695_wdt_stop(); return 0; } static int ks8695wdt_resume(struct platform_device *pdev) { if (ks8695wdt_busy) ks8695_wdt_start(); return 0; } #else #define ks8695wdt_suspend NULL #define ks8695wdt_resume NULL #endif static struct platform_driver ks8695wdt_driver = { .probe = ks8695wdt_probe, .remove = ks8695wdt_remove, .shutdown = ks8695wdt_shutdown, .suspend = ks8695wdt_suspend, .resume = ks8695wdt_resume, .driver = { .name = "ks8695_wdt", }, }; static int __init ks8695_wdt_init(void) { /* Check that the heartbeat value is within range; if not reset to the default */ if (ks8695_wdt_settimeout(wdt_time)) { ks8695_wdt_settimeout(WDT_DEFAULT_TIME); pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i" ", using %d\n", wdt_time, WDT_MAX_TIME); } return platform_driver_register(&ks8695wdt_driver); } static void __exit ks8695_wdt_exit(void) { platform_driver_unregister(&ks8695wdt_driver); } module_init(ks8695_wdt_init); module_exit(ks8695_wdt_exit); MODULE_AUTHOR("Andrew Victor"); MODULE_DESCRIPTION("Watchdog driver for KS8695"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:ks8695_wdt");