Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * AMD Elan SC520 processor Watchdog Timer driver |
| 3 | * |
Wim Van Sebroeck | 143a2e5 | 2009-03-18 08:35:09 +0000 | [diff] [blame] | 4 | * Based on acquirewdt.c by Alan Cox, |
| 5 | * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License |
| 9 | * as published by the Free Software Foundation; either version |
| 10 | * 2 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * The authors do NOT admit liability nor provide warranty for |
| 13 | * any of this software. This material is provided "AS-IS" in |
Wim Van Sebroeck | 143a2e5 | 2009-03-18 08:35:09 +0000 | [diff] [blame] | 14 | * the hope that it may be useful for others. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | * |
| 16 | * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net> |
| 17 | * 9/27 - 2001 [Initial release] |
| 18 | * |
| 19 | * Additional fixes Alan Cox |
| 20 | * - Fixed formatting |
| 21 | * - Removed debug printks |
| 22 | * - Fixed SMP built kernel deadlock |
| 23 | * - Switched to private locks not lock_kernel |
| 24 | * - Used ioremap/writew/readw |
| 25 | * - Added NOWAYOUT support |
| 26 | * 4/12 - 2002 Changes by Rob Radez <rob@osinvestor.com> |
| 27 | * - Change comments |
| 28 | * - Eliminate fop_llseek |
| 29 | * - Change CONFIG_WATCHDOG_NOWAYOUT semantics |
| 30 | * - Add KERN_* tags to printks |
| 31 | * - fix possible wdt_is_open race |
| 32 | * - Report proper capabilities in watchdog_info |
| 33 | * - Add WDIOC_{GETSTATUS, GETBOOTSTATUS, SETTIMEOUT, |
| 34 | * GETTIMEOUT, SETOPTIONS} ioctls |
| 35 | * 09/8 - 2003 Changes by Wim Van Sebroeck <wim@iguana.be> |
| 36 | * - cleanup of trailing spaces |
| 37 | * - added extra printk's for startup problems |
| 38 | * - use module_param |
| 39 | * - made timeout (the emulated heartbeat) a module_param |
| 40 | * - made the keepalive ping an internal subroutine |
| 41 | * 3/27 - 2004 Changes by Sean Young <sean@mess.org> |
| 42 | * - set MMCR_BASE to 0xfffef000 |
| 43 | * - CBAR does not need to be read |
| 44 | * - removed debugging printks |
| 45 | * |
| 46 | * This WDT driver is different from most other Linux WDT |
| 47 | * drivers in that the driver will ping the watchdog by itself, |
| 48 | * because this particular WDT has a very short timeout (1.6 |
| 49 | * seconds) and it would be insane to count on any userspace |
| 50 | * daemon always getting scheduled within that time frame. |
| 51 | * |
| 52 | * This driver uses memory mapped IO, and spinlock. |
| 53 | */ |
| 54 | |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 55 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 56 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | #include <linux/module.h> |
| 58 | #include <linux/moduleparam.h> |
| 59 | #include <linux/types.h> |
| 60 | #include <linux/timer.h> |
| 61 | #include <linux/miscdevice.h> |
| 62 | #include <linux/watchdog.h> |
| 63 | #include <linux/fs.h> |
| 64 | #include <linux/ioport.h> |
| 65 | #include <linux/notifier.h> |
| 66 | #include <linux/reboot.h> |
| 67 | #include <linux/init.h> |
Tim Schmielau | 4e57b68 | 2005-10-30 15:03:48 -0800 | [diff] [blame] | 68 | #include <linux/jiffies.h> |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 69 | #include <linux/io.h> |
| 70 | #include <linux/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | /* |
| 74 | * The AMD Elan SC520 timeout value is 492us times a power of 2 (0-7) |
| 75 | * |
| 76 | * 0: 492us 2: 1.01s 4: 4.03s 6: 16.22s |
| 77 | * 1: 503ms 3: 2.01s 5: 8.05s 7: 32.21s |
| 78 | * |
| 79 | * We will program the SC520 watchdog for a timeout of 2.01s. |
| 80 | * If we reset the watchdog every ~250ms we should be safe. |
| 81 | */ |
| 82 | |
| 83 | #define WDT_INTERVAL (HZ/4+1) |
| 84 | |
| 85 | /* |
| 86 | * We must not require too good response from the userspace daemon. |
| 87 | * Here we require the userspace daemon to send us a heartbeat |
| 88 | * char to /dev/watchdog every 30 seconds. |
| 89 | */ |
| 90 | |
| 91 | #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 92 | /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ |
| 93 | static int timeout = WATCHDOG_TIMEOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | module_param(timeout, int, 0); |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 95 | MODULE_PARM_DESC(timeout, |
| 96 | "Watchdog timeout in seconds. (1 <= timeout <= 3600, default=" |
| 97 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | |
Wim Van Sebroeck | 86a1e18 | 2012-03-05 16:51:11 +0100 | [diff] [blame] | 99 | static bool nowayout = WATCHDOG_NOWAYOUT; |
| 100 | module_param(nowayout, bool, 0); |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 101 | MODULE_PARM_DESC(nowayout, |
| 102 | "Watchdog cannot be stopped once started (default=" |
| 103 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | |
| 105 | /* |
| 106 | * AMD Elan SC520 - Watchdog Timer Registers |
| 107 | */ |
| 108 | #define MMCR_BASE 0xfffef000 /* The default base address */ |
| 109 | #define OFFS_WDTMRCTL 0xCB0 /* Watchdog Timer Control Register */ |
| 110 | |
| 111 | /* WDT Control Register bit definitions */ |
| 112 | #define WDT_EXP_SEL_01 0x0001 /* [01] Time-out = 496 us (with 33 Mhz clk). */ |
| 113 | #define WDT_EXP_SEL_02 0x0002 /* [02] Time-out = 508 ms (with 33 Mhz clk). */ |
| 114 | #define WDT_EXP_SEL_03 0x0004 /* [03] Time-out = 1.02 s (with 33 Mhz clk). */ |
| 115 | #define WDT_EXP_SEL_04 0x0008 /* [04] Time-out = 2.03 s (with 33 Mhz clk). */ |
| 116 | #define WDT_EXP_SEL_05 0x0010 /* [05] Time-out = 4.07 s (with 33 Mhz clk). */ |
| 117 | #define WDT_EXP_SEL_06 0x0020 /* [06] Time-out = 8.13 s (with 33 Mhz clk). */ |
| 118 | #define WDT_EXP_SEL_07 0x0040 /* [07] Time-out = 16.27s (with 33 Mhz clk). */ |
| 119 | #define WDT_EXP_SEL_08 0x0080 /* [08] Time-out = 32.54s (with 33 Mhz clk). */ |
| 120 | #define WDT_IRQ_FLG 0x1000 /* [12] Interrupt Request Flag */ |
| 121 | #define WDT_WRST_ENB 0x4000 /* [14] Watchdog Timer Reset Enable */ |
| 122 | #define WDT_ENB 0x8000 /* [15] Watchdog Timer Enable */ |
| 123 | |
| 124 | static __u16 __iomem *wdtmrctl; |
| 125 | |
| 126 | static void wdt_timer_ping(unsigned long); |
Jiri Slaby | 82eb7c5 | 2007-02-08 18:39:36 +0100 | [diff] [blame] | 127 | static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | static unsigned long next_heartbeat; |
| 129 | static unsigned long wdt_is_open; |
| 130 | static char wdt_expect_close; |
Alexey Dobriyan | c7dfd0c | 2007-11-01 16:27:08 -0700 | [diff] [blame] | 131 | static DEFINE_SPINLOCK(wdt_spinlock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | |
| 133 | /* |
| 134 | * Whack the dog |
| 135 | */ |
| 136 | |
| 137 | static void wdt_timer_ping(unsigned long data) |
| 138 | { |
| 139 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL |
| 140 | * we agree to ping the WDT |
| 141 | */ |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 142 | if (time_before(jiffies, next_heartbeat)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | /* Ping the WDT */ |
| 144 | spin_lock(&wdt_spinlock); |
| 145 | writew(0xAAAA, wdtmrctl); |
| 146 | writew(0x5555, wdtmrctl); |
| 147 | spin_unlock(&wdt_spinlock); |
| 148 | |
| 149 | /* Re-set the timer interval */ |
Jiri Slaby | 82eb7c5 | 2007-02-08 18:39:36 +0100 | [diff] [blame] | 150 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 151 | } else |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 152 | pr_warn("Heartbeat lost! Will not ping the watchdog\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | } |
| 154 | |
| 155 | /* |
| 156 | * Utility routines |
| 157 | */ |
| 158 | |
| 159 | static void wdt_config(int writeval) |
| 160 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | unsigned long flags; |
| 162 | |
| 163 | /* buy some time (ping) */ |
| 164 | spin_lock_irqsave(&wdt_spinlock, flags); |
Alexander Shiyan | a9ba837 | 2014-02-15 13:22:49 +0400 | [diff] [blame] | 165 | readw(wdtmrctl); /* ensure write synchronization */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | writew(0xAAAA, wdtmrctl); |
| 167 | writew(0x5555, wdtmrctl); |
| 168 | /* unlock WDT = make WDT configuration register writable one time */ |
| 169 | writew(0x3333, wdtmrctl); |
| 170 | writew(0xCCCC, wdtmrctl); |
| 171 | /* write WDT configuration register */ |
| 172 | writew(writeval, wdtmrctl); |
| 173 | spin_unlock_irqrestore(&wdt_spinlock, flags); |
| 174 | } |
| 175 | |
| 176 | static int wdt_startup(void) |
| 177 | { |
| 178 | next_heartbeat = jiffies + (timeout * HZ); |
| 179 | |
| 180 | /* Start the timer */ |
Jiri Slaby | 82eb7c5 | 2007-02-08 18:39:36 +0100 | [diff] [blame] | 181 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | |
| 183 | /* Start the watchdog */ |
| 184 | wdt_config(WDT_ENB | WDT_WRST_ENB | WDT_EXP_SEL_04); |
| 185 | |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 186 | pr_info("Watchdog timer is now enabled\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | return 0; |
| 188 | } |
| 189 | |
| 190 | static int wdt_turnoff(void) |
| 191 | { |
| 192 | /* Stop the timer */ |
| 193 | del_timer(&timer); |
| 194 | |
| 195 | /* Stop the watchdog */ |
| 196 | wdt_config(0); |
| 197 | |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 198 | pr_info("Watchdog timer is now disabled...\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | return 0; |
| 200 | } |
| 201 | |
| 202 | static int wdt_keepalive(void) |
| 203 | { |
| 204 | /* user land ping */ |
| 205 | next_heartbeat = jiffies + (timeout * HZ); |
| 206 | return 0; |
| 207 | } |
| 208 | |
| 209 | static int wdt_set_heartbeat(int t) |
| 210 | { |
| 211 | if ((t < 1) || (t > 3600)) /* arbitrary upper limit */ |
| 212 | return -EINVAL; |
| 213 | |
| 214 | timeout = t; |
| 215 | return 0; |
| 216 | } |
| 217 | |
| 218 | /* |
| 219 | * /dev/watchdog handling |
| 220 | */ |
| 221 | |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 222 | static ssize_t fop_write(struct file *file, const char __user *buf, |
| 223 | size_t count, loff_t *ppos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | { |
| 225 | /* See if we got the magic character 'V' and reload the timer */ |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 226 | if (count) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | if (!nowayout) { |
| 228 | size_t ofs; |
| 229 | |
| 230 | /* note: just in case someone wrote the magic character |
| 231 | * five months ago... */ |
| 232 | wdt_expect_close = 0; |
| 233 | |
| 234 | /* now scan */ |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 235 | for (ofs = 0; ofs != count; ofs++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | char c; |
| 237 | if (get_user(c, buf + ofs)) |
| 238 | return -EFAULT; |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 239 | if (c == 'V') |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | wdt_expect_close = 42; |
| 241 | } |
| 242 | } |
| 243 | |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 244 | /* Well, anyhow someone wrote to us, we should |
| 245 | return that favour */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | wdt_keepalive(); |
| 247 | } |
| 248 | return count; |
| 249 | } |
| 250 | |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 251 | static int fop_open(struct inode *inode, struct file *file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | /* Just in case we're already talking to someone... */ |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 254 | if (test_and_set_bit(0, &wdt_is_open)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | return -EBUSY; |
| 256 | if (nowayout) |
| 257 | __module_get(THIS_MODULE); |
| 258 | |
| 259 | /* Good, fire up the show */ |
| 260 | wdt_startup(); |
Wim Van Sebroeck | 6abe78b | 2007-07-24 21:38:37 +0000 | [diff] [blame] | 261 | return nonseekable_open(inode, file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | } |
| 263 | |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 264 | static int fop_close(struct inode *inode, struct file *file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | { |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 266 | if (wdt_expect_close == 42) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | wdt_turnoff(); |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 268 | else { |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 269 | pr_crit("Unexpected close, not stopping watchdog!\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | wdt_keepalive(); |
| 271 | } |
| 272 | clear_bit(0, &wdt_is_open); |
| 273 | wdt_expect_close = 0; |
| 274 | return 0; |
| 275 | } |
| 276 | |
Alan Cox | 9b748ed | 2008-05-19 14:08:49 +0100 | [diff] [blame] | 277 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | { |
| 279 | void __user *argp = (void __user *)arg; |
| 280 | int __user *p = argp; |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 281 | static const struct watchdog_info ident = { |
| 282 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
| 283 | | WDIOF_MAGICCLOSE, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | .firmware_version = 1, |
| 285 | .identity = "SC520", |
| 286 | }; |
| 287 | |
Wim Van Sebroeck | 5eb8249 | 2008-07-17 18:08:47 +0000 | [diff] [blame] | 288 | switch (cmd) { |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 289 | case WDIOC_GETSUPPORT: |
| 290 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
| 291 | case WDIOC_GETSTATUS: |
| 292 | case WDIOC_GETBOOTSTATUS: |
| 293 | return put_user(0, p); |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 294 | case WDIOC_SETOPTIONS: |
| 295 | { |
| 296 | int new_options, retval = -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 298 | if (get_user(new_options, p)) |
| 299 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 301 | if (new_options & WDIOS_DISABLECARD) { |
| 302 | wdt_turnoff(); |
| 303 | retval = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 304 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 306 | if (new_options & WDIOS_ENABLECARD) { |
| 307 | wdt_startup(); |
| 308 | retval = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 | } |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 310 | |
| 311 | return retval; |
| 312 | } |
Wim Van Sebroeck | 0c06090c | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 313 | case WDIOC_KEEPALIVE: |
| 314 | wdt_keepalive(); |
| 315 | return 0; |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 316 | case WDIOC_SETTIMEOUT: |
| 317 | { |
| 318 | int new_timeout; |
| 319 | |
| 320 | if (get_user(new_timeout, p)) |
| 321 | return -EFAULT; |
| 322 | |
| 323 | if (wdt_set_heartbeat(new_timeout)) |
| 324 | return -EINVAL; |
| 325 | |
| 326 | wdt_keepalive(); |
| 327 | /* Fall through */ |
| 328 | } |
| 329 | case WDIOC_GETTIMEOUT: |
| 330 | return put_user(timeout, p); |
Wim Van Sebroeck | 0c06090c | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 331 | default: |
| 332 | return -ENOTTY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | } |
| 334 | } |
| 335 | |
Arjan van de Ven | 62322d2 | 2006-07-03 00:24:21 -0700 | [diff] [blame] | 336 | static const struct file_operations wdt_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | .owner = THIS_MODULE, |
| 338 | .llseek = no_llseek, |
| 339 | .write = fop_write, |
| 340 | .open = fop_open, |
| 341 | .release = fop_close, |
Alan Cox | 9b748ed | 2008-05-19 14:08:49 +0100 | [diff] [blame] | 342 | .unlocked_ioctl = fop_ioctl, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 343 | }; |
| 344 | |
| 345 | static struct miscdevice wdt_miscdev = { |
| 346 | .minor = WATCHDOG_MINOR, |
| 347 | .name = "watchdog", |
| 348 | .fops = &wdt_fops, |
| 349 | }; |
| 350 | |
| 351 | /* |
| 352 | * Notifier for system down |
| 353 | */ |
| 354 | |
| 355 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, |
| 356 | void *unused) |
| 357 | { |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 358 | if (code == SYS_DOWN || code == SYS_HALT) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | wdt_turnoff(); |
| 360 | return NOTIFY_DONE; |
| 361 | } |
| 362 | |
| 363 | /* |
| 364 | * The WDT needs to learn about soft shutdowns in order to |
| 365 | * turn the timebomb registers off. |
| 366 | */ |
| 367 | |
| 368 | static struct notifier_block wdt_notifier = { |
| 369 | .notifier_call = wdt_notify_sys, |
| 370 | }; |
| 371 | |
| 372 | static void __exit sc520_wdt_unload(void) |
| 373 | { |
| 374 | if (!nowayout) |
| 375 | wdt_turnoff(); |
| 376 | |
| 377 | /* Deregister */ |
| 378 | misc_deregister(&wdt_miscdev); |
| 379 | unregister_reboot_notifier(&wdt_notifier); |
| 380 | iounmap(wdtmrctl); |
| 381 | } |
| 382 | |
| 383 | static int __init sc520_wdt_init(void) |
| 384 | { |
| 385 | int rc = -EBUSY; |
| 386 | |
Alan Cox | ff94806 | 2008-05-19 14:08:44 +0100 | [diff] [blame] | 387 | /* Check that the timeout value is within it's range ; |
| 388 | if not reset to the default */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 389 | if (wdt_set_heartbeat(timeout)) { |
| 390 | wdt_set_heartbeat(WATCHDOG_TIMEOUT); |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 391 | pr_info("timeout value must be 1 <= timeout <= 3600, using %d\n", |
| 392 | WATCHDOG_TIMEOUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | } |
| 394 | |
Sean Young | cef153a | 2011-08-23 22:30:09 +0100 | [diff] [blame] | 395 | wdtmrctl = ioremap(MMCR_BASE + OFFS_WDTMRCTL, 2); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | if (!wdtmrctl) { |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 397 | pr_err("Unable to remap memory\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 398 | rc = -ENOMEM; |
| 399 | goto err_out_region2; |
| 400 | } |
| 401 | |
| 402 | rc = register_reboot_notifier(&wdt_notifier); |
| 403 | if (rc) { |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 404 | pr_err("cannot register reboot notifier (err=%d)\n", rc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | goto err_out_ioremap; |
| 406 | } |
| 407 | |
| 408 | rc = misc_register(&wdt_miscdev); |
| 409 | if (rc) { |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 410 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
| 411 | WATCHDOG_MINOR, rc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | goto err_out_notifier; |
| 413 | } |
| 414 | |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 415 | pr_info("WDT driver for SC520 initialised. timeout=%d sec (nowayout=%d)\n", |
| 416 | timeout, nowayout); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | |
| 418 | return 0; |
| 419 | |
| 420 | err_out_notifier: |
| 421 | unregister_reboot_notifier(&wdt_notifier); |
| 422 | err_out_ioremap: |
| 423 | iounmap(wdtmrctl); |
| 424 | err_out_region2: |
| 425 | return rc; |
| 426 | } |
| 427 | |
| 428 | module_init(sc520_wdt_init); |
| 429 | module_exit(sc520_wdt_unload); |
| 430 | |
| 431 | MODULE_AUTHOR("Scott and Bill Jennings"); |
Wim Van Sebroeck | 143a2e5 | 2009-03-18 08:35:09 +0000 | [diff] [blame] | 432 | MODULE_DESCRIPTION( |
| 433 | "Driver for watchdog timer in AMD \"Elan\" SC520 uProcessor"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | MODULE_LICENSE("GPL"); |