/* Watchdog timer for the Geode GX/LX with the CS5535/CS5536 companion chip * * Copyright (C) 2006-2007, Advanced Micro Devices, 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/moduleparam.h> #include <linux/types.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/fs.h> #include <linux/platform_device.h> #include <linux/reboot.h> #include <linux/uaccess.h> #include <asm/geode.h> #define GEODEWDT_HZ 500 #define GEODEWDT_SCALE 6 #define GEODEWDT_MAX_SECONDS 131 #define WDT_FLAGS_OPEN 1 #define WDT_FLAGS_ORPHAN 2 #define DRV_NAME "geodewdt" #define WATCHDOG_NAME "Geode GX/LX WDT" #define WATCHDOG_TIMEOUT 60 static int timeout = WATCHDOG_TIMEOUT; module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=131, 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) ")"); static struct platform_device *geodewdt_platform_device; static unsigned long wdt_flags; static int wdt_timer; static int safe_close; static void geodewdt_ping(void) { /* Stop the counter */ geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); /* Reset the counter */ geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); /* Enable the counter */ geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); } static void geodewdt_disable(void) { geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); } static int geodewdt_set_heartbeat(int val) { if (val < 1 || val > GEODEWDT_MAX_SECONDS) return -EINVAL; geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ); geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); timeout = val; return 0; } static int geodewdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags)) return -EBUSY; if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags)) __module_get(THIS_MODULE); geodewdt_ping(); return nonseekable_open(inode, file); } static int geodewdt_release(struct inode *inode, struct file *file) { if (safe_close) { geodewdt_disable(); module_put(THIS_MODULE); } else { printk(KERN_CRIT "Unexpected close - watchdog is not stopping.\n"); geodewdt_ping(); set_bit(WDT_FLAGS_ORPHAN, &wdt_flags); } clear_bit(WDT_FLAGS_OPEN, &wdt_flags); safe_close = 0; return 0; } static ssize_t geodewdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { if (len) { if (!nowayout) { size_t i; safe_close = 0; for (i = 0; i != len; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') safe_close = 1; } } geodewdt_ping(); } return len; } static long geodewdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; int interval; static struct watchdog_info ident = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = WATCHDOG_NAME, }; switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_SETOPTIONS: { int options, ret = -EINVAL; if (get_user(options, p)) return -EFAULT; if (options & WDIOS_DISABLECARD) { geodewdt_disable(); ret = 0; } if (options & WDIOS_ENABLECARD) { geodewdt_ping(); ret = 0; } return ret; } case WDIOC_KEEPALIVE: geodewdt_ping(); return 0; case WDIOC_SETTIMEOUT: if (get_user(interval, p)) return -EFAULT; if (geodewdt_set_heartbeat(interval)) return -EINVAL; /* Fall through */ case WDIOC_GETTIMEOUT: return put_user(timeout, p); default: return -ENOTTY; } return 0; } static const struct file_operations geodewdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = geodewdt_write, .unlocked_ioctl = geodewdt_ioctl, .open = geodewdt_open, .release = geodewdt_release, }; static struct miscdevice geodewdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &geodewdt_fops, }; static int __devinit geodewdt_probe(struct platform_device *dev) { int ret, timer; timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING); if (timer == -1) { printk(KERN_ERR "geodewdt: No timers were available\n"); return -ENODEV; } wdt_timer = timer; /* Set up the timer */ geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, GEODEWDT_SCALE | (3 << 8)); /* Set up comparator 2 to reset when the event fires */ geode_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1); /* Set up the initial timeout */ geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, timeout * GEODEWDT_HZ); ret = misc_register(&geodewdt_miscdev); return ret; } static int __devexit geodewdt_remove(struct platform_device *dev) { misc_deregister(&geodewdt_miscdev); return 0; } static void geodewdt_shutdown(struct platform_device *dev) { geodewdt_disable(); } static struct platform_driver geodewdt_driver = { .probe = geodewdt_probe, .remove = __devexit_p(geodewdt_remove), .shutdown = geodewdt_shutdown, .driver = { .owner = THIS_MODULE, .name = DRV_NAME, }, }; static int __init geodewdt_init(void) { int ret; ret = platform_driver_register(&geodewdt_driver); if (ret) return ret; geodewdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0); if (IS_ERR(geodewdt_platform_device)) { ret = PTR_ERR(geodewdt_platform_device); goto err; } return 0; err: platform_driver_unregister(&geodewdt_driver); return ret; } static void __exit geodewdt_exit(void) { platform_device_unregister(geodewdt_platform_device); platform_driver_unregister(&geodewdt_driver); } module_init(geodewdt_init); module_exit(geodewdt_exit); MODULE_AUTHOR("Advanced Micro Devices, Inc"); MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);