| /* 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 int geodewdt_ioctl(struct inode *inode, 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, |
| .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); |