Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Watchdog driver for Cirrus Logic EP93xx family of devices. |
| 3 | * |
| 4 | * Copyright (c) 2004 Ray Lehtiniemi |
| 5 | * Copyright (c) 2006 Tower Technologies |
| 6 | * Based on ep93xx driver, bits from alim7101_wdt.c |
| 7 | * |
| 8 | * Authors: Ray Lehtiniemi <rayl@mail.com>, |
| 9 | * Alessandro Zummo <a.zummo@towertech.it> |
| 10 | * |
| 11 | * This file is licensed under the terms of the GNU General Public |
| 12 | * License version 2. This program is licensed "as is" without any |
| 13 | * warranty of any kind, whether express or implied. |
| 14 | * |
| 15 | * This watchdog fires after 250msec, which is a too short interval |
| 16 | * for us to rely on the user space daemon alone. So we ping the |
| 17 | * wdt each ~200msec and eventually stop doing it if the user space |
| 18 | * daemon dies. |
| 19 | * |
| 20 | * TODO: |
| 21 | * |
| 22 | * - Test last reset from watchdog status |
| 23 | * - Add a few missing ioctls |
| 24 | */ |
| 25 | |
| 26 | #include <linux/module.h> |
| 27 | #include <linux/fs.h> |
| 28 | #include <linux/miscdevice.h> |
| 29 | #include <linux/watchdog.h> |
| 30 | #include <linux/timer.h> |
Alan Cox | f339e2a | 2008-05-19 14:05:35 +0100 | [diff] [blame] | 31 | #include <linux/uaccess.h> |
Ryan Mallon | 2653d1d | 2009-07-15 21:33:22 +0100 | [diff] [blame] | 32 | #include <linux/io.h> |
Russell King | a09e64f | 2008-08-05 16:14:15 +0100 | [diff] [blame] | 33 | #include <mach/hardware.h> |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 34 | |
| 35 | #define WDT_VERSION "0.3" |
| 36 | #define PFX "ep93xx_wdt: " |
| 37 | |
| 38 | /* default timeout (secs) */ |
| 39 | #define WDT_TIMEOUT 30 |
| 40 | |
| 41 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 42 | static int timeout = WDT_TIMEOUT; |
| 43 | |
| 44 | static struct timer_list timer; |
| 45 | static unsigned long next_heartbeat; |
| 46 | static unsigned long wdt_status; |
| 47 | static unsigned long boot_status; |
| 48 | |
| 49 | #define WDT_IN_USE 0 |
| 50 | #define WDT_OK_TO_CLOSE 1 |
| 51 | |
| 52 | #define EP93XX_WDT_REG(x) (EP93XX_WATCHDOG_BASE + (x)) |
| 53 | #define EP93XX_WDT_WATCHDOG EP93XX_WDT_REG(0x00) |
| 54 | #define EP93XX_WDT_WDSTATUS EP93XX_WDT_REG(0x04) |
| 55 | |
| 56 | /* reset the wdt every ~200ms */ |
| 57 | #define WDT_INTERVAL (HZ/5) |
| 58 | |
| 59 | static void wdt_enable(void) |
| 60 | { |
| 61 | __raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG); |
| 62 | } |
| 63 | |
| 64 | static void wdt_disable(void) |
| 65 | { |
| 66 | __raw_writew(0xaa55, EP93XX_WDT_WATCHDOG); |
| 67 | } |
| 68 | |
| 69 | static inline void wdt_ping(void) |
| 70 | { |
| 71 | __raw_writew(0x5555, EP93XX_WDT_WATCHDOG); |
| 72 | } |
| 73 | |
| 74 | static void wdt_startup(void) |
| 75 | { |
| 76 | next_heartbeat = jiffies + (timeout * HZ); |
| 77 | |
| 78 | wdt_enable(); |
| 79 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
| 80 | } |
| 81 | |
| 82 | static void wdt_shutdown(void) |
| 83 | { |
| 84 | del_timer_sync(&timer); |
| 85 | wdt_disable(); |
| 86 | } |
| 87 | |
| 88 | static void wdt_keepalive(void) |
| 89 | { |
| 90 | /* user land ping */ |
| 91 | next_heartbeat = jiffies + (timeout * HZ); |
| 92 | } |
| 93 | |
| 94 | static int ep93xx_wdt_open(struct inode *inode, struct file *file) |
| 95 | { |
| 96 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
| 97 | return -EBUSY; |
| 98 | |
| 99 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 100 | |
| 101 | wdt_startup(); |
| 102 | |
| 103 | return nonseekable_open(inode, file); |
| 104 | } |
| 105 | |
| 106 | static ssize_t |
| 107 | ep93xx_wdt_write(struct file *file, const char __user *data, size_t len, |
| 108 | loff_t *ppos) |
| 109 | { |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 110 | if (len) { |
| 111 | if (!nowayout) { |
| 112 | size_t i; |
| 113 | |
| 114 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 115 | |
| 116 | for (i = 0; i != len; i++) { |
| 117 | char c; |
| 118 | |
| 119 | if (get_user(c, data + i)) |
| 120 | return -EFAULT; |
| 121 | |
| 122 | if (c == 'V') |
| 123 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 124 | else |
| 125 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 126 | } |
| 127 | } |
| 128 | wdt_keepalive(); |
| 129 | } |
| 130 | |
| 131 | return len; |
| 132 | } |
| 133 | |
| 134 | static struct watchdog_info ident = { |
| 135 | .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE, |
| 136 | .identity = "EP93xx Watchdog", |
| 137 | }; |
| 138 | |
Alan Cox | f339e2a | 2008-05-19 14:05:35 +0100 | [diff] [blame] | 139 | static long ep93xx_wdt_ioctl(struct file *file, |
| 140 | unsigned int cmd, unsigned long arg) |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 141 | { |
Samuel Tardieu | 795b89d | 2006-09-09 17:34:31 +0200 | [diff] [blame] | 142 | int ret = -ENOTTY; |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 143 | |
| 144 | switch (cmd) { |
| 145 | case WDIOC_GETSUPPORT: |
| 146 | ret = copy_to_user((struct watchdog_info __user *)arg, &ident, |
| 147 | sizeof(ident)) ? -EFAULT : 0; |
| 148 | break; |
| 149 | |
| 150 | case WDIOC_GETSTATUS: |
| 151 | ret = put_user(0, (int __user *)arg); |
| 152 | break; |
| 153 | |
| 154 | case WDIOC_GETBOOTSTATUS: |
| 155 | ret = put_user(boot_status, (int __user *)arg); |
| 156 | break; |
| 157 | |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 158 | case WDIOC_KEEPALIVE: |
| 159 | wdt_keepalive(); |
| 160 | ret = 0; |
| 161 | break; |
Wim Van Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 162 | |
| 163 | case WDIOC_GETTIMEOUT: |
| 164 | /* actually, it is 0.250 seconds.... */ |
| 165 | ret = put_user(1, (int __user *)arg); |
| 166 | break; |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 167 | } |
| 168 | return ret; |
| 169 | } |
| 170 | |
| 171 | static int ep93xx_wdt_release(struct inode *inode, struct file *file) |
| 172 | { |
| 173 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) |
| 174 | wdt_shutdown(); |
| 175 | else |
Alan Cox | f339e2a | 2008-05-19 14:05:35 +0100 | [diff] [blame] | 176 | printk(KERN_CRIT PFX |
| 177 | "Device closed unexpectedly - timer will not stop\n"); |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 178 | |
| 179 | clear_bit(WDT_IN_USE, &wdt_status); |
| 180 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 181 | |
| 182 | return 0; |
| 183 | } |
| 184 | |
Arjan van de Ven | 62322d2 | 2006-07-03 00:24:21 -0700 | [diff] [blame] | 185 | static const struct file_operations ep93xx_wdt_fops = { |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 186 | .owner = THIS_MODULE, |
| 187 | .write = ep93xx_wdt_write, |
Alan Cox | f339e2a | 2008-05-19 14:05:35 +0100 | [diff] [blame] | 188 | .unlocked_ioctl = ep93xx_wdt_ioctl, |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 189 | .open = ep93xx_wdt_open, |
| 190 | .release = ep93xx_wdt_release, |
| 191 | }; |
| 192 | |
| 193 | static struct miscdevice ep93xx_wdt_miscdev = { |
| 194 | .minor = WATCHDOG_MINOR, |
| 195 | .name = "watchdog", |
| 196 | .fops = &ep93xx_wdt_fops, |
| 197 | }; |
| 198 | |
| 199 | static void ep93xx_timer_ping(unsigned long data) |
| 200 | { |
| 201 | if (time_before(jiffies, next_heartbeat)) |
| 202 | wdt_ping(); |
| 203 | |
| 204 | /* Re-set the timer interval */ |
| 205 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
| 206 | } |
| 207 | |
| 208 | static int __init ep93xx_wdt_init(void) |
| 209 | { |
| 210 | int err; |
| 211 | |
| 212 | err = misc_register(&ep93xx_wdt_miscdev); |
| 213 | |
| 214 | boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0; |
| 215 | |
| 216 | printk(KERN_INFO PFX "EP93XX watchdog, driver version " |
| 217 | WDT_VERSION "%s\n", |
| 218 | (__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08) |
| 219 | ? " (nCS1 disable detected)" : ""); |
| 220 | |
| 221 | if (timeout < 1 || timeout > 3600) { |
| 222 | timeout = WDT_TIMEOUT; |
| 223 | printk(KERN_INFO PFX |
| 224 | "timeout value must be 1<=x<=3600, using %d\n", |
| 225 | timeout); |
| 226 | } |
| 227 | |
| 228 | setup_timer(&timer, ep93xx_timer_ping, 1); |
| 229 | return err; |
| 230 | } |
| 231 | |
| 232 | static void __exit ep93xx_wdt_exit(void) |
| 233 | { |
| 234 | wdt_shutdown(); |
| 235 | misc_deregister(&ep93xx_wdt_miscdev); |
| 236 | } |
| 237 | |
| 238 | module_init(ep93xx_wdt_init); |
| 239 | module_exit(ep93xx_wdt_exit); |
| 240 | |
| 241 | module_param(nowayout, int, 0); |
| 242 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
| 243 | |
| 244 | module_param(timeout, int, 0); |
Alan Cox | f339e2a | 2008-05-19 14:05:35 +0100 | [diff] [blame] | 245 | MODULE_PARM_DESC(timeout, |
| 246 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" |
| 247 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
Alessandro Zummo | f52ac8f | 2006-03-25 03:06:37 -0800 | [diff] [blame] | 248 | |
| 249 | MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>," |
| 250 | "Alessandro Zummo <a.zummo@towertech.it>"); |
| 251 | MODULE_DESCRIPTION("EP93xx Watchdog"); |
| 252 | MODULE_LICENSE("GPL"); |
| 253 | MODULE_VERSION(WDT_VERSION); |
| 254 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |