blob: 6185af2b33109c5ce8c1ef71a93b35eb2542bfdd [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Paul Mundtb1fa8882010-05-24 10:55:59 +09002 * drivers/watchdog/shwdt.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * Watchdog driver for integrated watchdog in the SuperH processors.
5 *
Paul Mundt40968122012-05-10 14:21:15 +09006 * Copyright (C) 2001 - 2012 Paul Mundt <lethal@linux-sh.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version.
12 *
13 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
14 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
15 *
16 * 19-Apr-2002 Rob Radez <rob@osinvestor.com>
17 * Added expect close support, made emulated timeout runtime changeable
18 * general cleanups, add some ioctls
19 */
Joe Perches27c766a2012-02-15 15:06:19 -080020
21#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/module.h>
24#include <linux/moduleparam.h>
Paul Mundt8f5585e2010-05-25 18:31:12 +090025#include <linux/platform_device.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/init.h>
27#include <linux/types.h>
Paul Mundtf9fb3602012-05-10 15:15:08 +090028#include <linux/spinlock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <linux/miscdevice.h>
30#include <linux/watchdog.h>
Paul Mundt8c013d962012-05-10 16:08:35 +090031#include <linux/pm_runtime.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/fs.h>
Paul Mundtf1184202006-09-27 17:53:59 +090033#include <linux/mm.h>
Paul Mundt8f5585e2010-05-25 18:31:12 +090034#include <linux/slab.h>
Alan Cox70b814e2008-05-19 14:08:55 +010035#include <linux/io.h>
Paul Mundt9ea64042012-05-10 15:46:48 +090036#include <linux/clk.h>
Sachin Kamat6330c702013-03-04 10:36:41 +053037#include <linux/err.h>
Adrian Bunk58cf4192008-08-08 18:39:11 +030038#include <asm/watchdog.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Paul Mundt8f5585e2010-05-25 18:31:12 +090040#define DRV_NAME "sh-wdt"
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42/*
43 * Default clock division ratio is 5.25 msecs. For an additional table of
44 * values, consult the asm-sh/watchdog.h. Overload this at module load
45 * time.
46 *
47 * In order for this to work reliably we need to have HZ set to 1000 or
48 * something quite higher than 100 (or we need a proper high-res timer
49 * implementation that will deal with this properly), otherwise the 10ms
50 * resolution of a jiffy is enough to trigger the overflow. For things like
51 * the SH-4 and SH-5, this isn't necessarily that big of a problem, though
52 * for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely
53 * necssary.
54 *
55 * As a result of this timing problem, the only modes that are particularly
Lucas De Marchi25985ed2011-03-30 22:57:33 -030056 * feasible are the 4096 and the 2048 divisors, which yield 5.25 and 2.62ms
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 * overflow periods respectively.
58 *
59 * Also, since we can't really expect userspace to be responsive enough
Joe Perchesee0fc092008-02-03 17:32:52 +020060 * before the overflow happens, we maintain two separate timers .. One in
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 * the kernel for clearing out WOVF every 2ms or so (again, this depends on
62 * HZ == 1000), and another for monitoring userspace writes to the WDT device.
63 *
64 * As such, we currently use a configurable heartbeat interval which defaults
65 * to 30s. In this case, the userspace daemon is only responsible for periodic
66 * writes to the device before the next heartbeat is scheduled. If the daemon
67 * misses its deadline, the kernel timer will allow the WDT to overflow.
68 */
69static int clock_division_ratio = WTCSR_CKS_4096;
David Engrafbea19062011-07-20 15:03:39 +020070#define next_ping_period(cks) (jiffies + msecs_to_jiffies(cks - 4))
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
Linus Torvalds1da177e2005-04-16 15:20:36 -070072#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat */
73static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010074static bool nowayout = WATCHDOG_NOWAYOUT;
Paul Mundt8f5585e2010-05-25 18:31:12 +090075static unsigned long next_heartbeat;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
Paul Mundt8f5585e2010-05-25 18:31:12 +090077struct sh_wdt {
78 void __iomem *base;
79 struct device *dev;
Paul Mundt9ea64042012-05-10 15:46:48 +090080 struct clk *clk;
Paul Mundtf9fb3602012-05-10 15:15:08 +090081 spinlock_t lock;
Paul Mundt8f5585e2010-05-25 18:31:12 +090082
83 struct timer_list timer;
Paul Mundt8f5585e2010-05-25 18:31:12 +090084};
85
Paul Mundt1950f492012-05-10 15:07:53 +090086static int sh_wdt_start(struct watchdog_device *wdt_dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070087{
Paul Mundt1950f492012-05-10 15:07:53 +090088 struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev);
Alan Cox70b814e2008-05-19 14:08:55 +010089 unsigned long flags;
Paul Mundt8f5585e2010-05-25 18:31:12 +090090 u8 csr;
Alan Cox70b814e2008-05-19 14:08:55 +010091
Paul Mundt8c013d962012-05-10 16:08:35 +090092 pm_runtime_get_sync(wdt->dev);
Paul Mundtd42c9742012-05-10 16:14:40 +090093 clk_enable(wdt->clk);
Paul Mundt8c013d962012-05-10 16:08:35 +090094
Paul Mundtf9fb3602012-05-10 15:15:08 +090095 spin_lock_irqsave(&wdt->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97 next_heartbeat = jiffies + (heartbeat * HZ);
Paul Mundt8f5585e2010-05-25 18:31:12 +090098 mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
100 csr = sh_wdt_read_csr();
101 csr |= WTCSR_WT | clock_division_ratio;
102 sh_wdt_write_csr(csr);
103
104 sh_wdt_write_cnt(0);
105
106 /*
107 * These processors have a bit of an inconsistent initialization
108 * process.. starting with SH-3, RSTS was moved to WTCSR, and the
109 * RSTCSR register was removed.
110 *
111 * On the SH-2 however, in addition with bits being in different
112 * locations, we must deal with RSTCSR outright..
113 */
114 csr = sh_wdt_read_csr();
115 csr |= WTCSR_TME;
116 csr &= ~WTCSR_RSTS;
117 sh_wdt_write_csr(csr);
118
119#ifdef CONFIG_CPU_SH2
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 csr = sh_wdt_read_rstcsr();
121 csr &= ~RSTCSR_RSTS;
122 sh_wdt_write_rstcsr(csr);
123#endif
Paul Mundtf9fb3602012-05-10 15:15:08 +0900124 spin_unlock_irqrestore(&wdt->lock, flags);
Paul Mundt1950f492012-05-10 15:07:53 +0900125
126 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127}
128
Paul Mundt1950f492012-05-10 15:07:53 +0900129static int sh_wdt_stop(struct watchdog_device *wdt_dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130{
Paul Mundt1950f492012-05-10 15:07:53 +0900131 struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev);
Alan Cox70b814e2008-05-19 14:08:55 +0100132 unsigned long flags;
Paul Mundt8f5585e2010-05-25 18:31:12 +0900133 u8 csr;
Alan Cox70b814e2008-05-19 14:08:55 +0100134
Paul Mundtf9fb3602012-05-10 15:15:08 +0900135 spin_lock_irqsave(&wdt->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
Paul Mundt8f5585e2010-05-25 18:31:12 +0900137 del_timer(&wdt->timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
139 csr = sh_wdt_read_csr();
140 csr &= ~WTCSR_TME;
141 sh_wdt_write_csr(csr);
Paul Mundt8f5585e2010-05-25 18:31:12 +0900142
Paul Mundtf9fb3602012-05-10 15:15:08 +0900143 spin_unlock_irqrestore(&wdt->lock, flags);
Paul Mundt1950f492012-05-10 15:07:53 +0900144
Paul Mundtd42c9742012-05-10 16:14:40 +0900145 clk_disable(wdt->clk);
Paul Mundt8c013d962012-05-10 16:08:35 +0900146 pm_runtime_put_sync(wdt->dev);
147
Paul Mundt1950f492012-05-10 15:07:53 +0900148 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149}
150
Paul Mundt1950f492012-05-10 15:07:53 +0900151static int sh_wdt_keepalive(struct watchdog_device *wdt_dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152{
Paul Mundtf9fb3602012-05-10 15:15:08 +0900153 struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev);
Alan Cox70b814e2008-05-19 14:08:55 +0100154 unsigned long flags;
155
Paul Mundtf9fb3602012-05-10 15:15:08 +0900156 spin_lock_irqsave(&wdt->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 next_heartbeat = jiffies + (heartbeat * HZ);
Paul Mundtf9fb3602012-05-10 15:15:08 +0900158 spin_unlock_irqrestore(&wdt->lock, flags);
Paul Mundt1950f492012-05-10 15:07:53 +0900159
160 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161}
162
Paul Mundt1950f492012-05-10 15:07:53 +0900163static int sh_wdt_set_heartbeat(struct watchdog_device *wdt_dev, unsigned t)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164{
Paul Mundtf9fb3602012-05-10 15:15:08 +0900165 struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev);
Alan Cox70b814e2008-05-19 14:08:55 +0100166 unsigned long flags;
167
168 if (unlikely(t < 1 || t > 3600)) /* arbitrary upper limit */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 return -EINVAL;
170
Paul Mundtf9fb3602012-05-10 15:15:08 +0900171 spin_lock_irqsave(&wdt->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 heartbeat = t;
Paul Mundt1950f492012-05-10 15:07:53 +0900173 wdt_dev->timeout = t;
Paul Mundtf9fb3602012-05-10 15:15:08 +0900174 spin_unlock_irqrestore(&wdt->lock, flags);
Paul Mundt1950f492012-05-10 15:07:53 +0900175
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 return 0;
177}
178
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179static void sh_wdt_ping(unsigned long data)
180{
Paul Mundt8f5585e2010-05-25 18:31:12 +0900181 struct sh_wdt *wdt = (struct sh_wdt *)data;
Alan Cox70b814e2008-05-19 14:08:55 +0100182 unsigned long flags;
183
Paul Mundtf9fb3602012-05-10 15:15:08 +0900184 spin_lock_irqsave(&wdt->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 if (time_before(jiffies, next_heartbeat)) {
Paul Mundt8f5585e2010-05-25 18:31:12 +0900186 u8 csr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
188 csr = sh_wdt_read_csr();
189 csr &= ~WTCSR_IOVF;
190 sh_wdt_write_csr(csr);
191
192 sh_wdt_write_cnt(0);
193
Paul Mundt8f5585e2010-05-25 18:31:12 +0900194 mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
Paul Mundte4c2cfe2006-09-27 12:31:01 +0900195 } else
Paul Mundt8f5585e2010-05-25 18:31:12 +0900196 dev_warn(wdt->dev, "Heartbeat lost! Will not ping "
197 "the watchdog\n");
Paul Mundtf9fb3602012-05-10 15:15:08 +0900198 spin_unlock_irqrestore(&wdt->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199}
200
Alan Cox70b814e2008-05-19 14:08:55 +0100201static const struct watchdog_info sh_wdt_info = {
Paul Mundte4c2cfe2006-09-27 12:31:01 +0900202 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
203 WDIOF_MAGICCLOSE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 .firmware_version = 1,
205 .identity = "SH WDT",
206};
207
Paul Mundt1950f492012-05-10 15:07:53 +0900208static const struct watchdog_ops sh_wdt_ops = {
209 .owner = THIS_MODULE,
210 .start = sh_wdt_start,
211 .stop = sh_wdt_stop,
212 .ping = sh_wdt_keepalive,
213 .set_timeout = sh_wdt_set_heartbeat,
214};
215
216static struct watchdog_device sh_wdt_dev = {
217 .info = &sh_wdt_info,
218 .ops = &sh_wdt_ops,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219};
220
Bill Pemberton2d991a12012-11-19 13:21:41 -0500221static int sh_wdt_probe(struct platform_device *pdev)
Paul Mundt8f5585e2010-05-25 18:31:12 +0900222{
223 struct sh_wdt *wdt;
224 struct resource *res;
225 int rc;
226
227 /*
228 * As this driver only covers the global watchdog case, reject
229 * any attempts to register per-CPU watchdogs.
230 */
231 if (pdev->id != -1)
232 return -EINVAL;
233
234 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
235 if (unlikely(!res))
236 return -EINVAL;
237
Paul Mundt8f5585e2010-05-25 18:31:12 +0900238 wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL);
Paul Mundt9ea64042012-05-10 15:46:48 +0900239 if (unlikely(!wdt))
240 return -ENOMEM;
Paul Mundt8f5585e2010-05-25 18:31:12 +0900241
242 wdt->dev = &pdev->dev;
243
Paul Mundt9ea64042012-05-10 15:46:48 +0900244 wdt->clk = clk_get(&pdev->dev, NULL);
245 if (IS_ERR(wdt->clk)) {
246 /*
247 * Clock framework support is optional, continue on
248 * anyways if we don't find a matching clock.
249 */
250 wdt->clk = NULL;
251 }
252
Sachin Kamat6330c702013-03-04 10:36:41 +0530253 wdt->base = devm_ioremap_resource(wdt->dev, res);
254 if (IS_ERR(wdt->base)) {
255 rc = PTR_ERR(wdt->base);
Paul Mundtd42c9742012-05-10 16:14:40 +0900256 goto err;
Paul Mundt9ea64042012-05-10 15:46:48 +0900257 }
258
Paul Mundtf9fb3602012-05-10 15:15:08 +0900259 watchdog_set_nowayout(&sh_wdt_dev, nowayout);
260 watchdog_set_drvdata(&sh_wdt_dev, wdt);
261
Paul Mundtf9fb3602012-05-10 15:15:08 +0900262 spin_lock_init(&wdt->lock);
263
Paul Mundt1950f492012-05-10 15:07:53 +0900264 rc = sh_wdt_set_heartbeat(&sh_wdt_dev, heartbeat);
Paul Mundt8f5585e2010-05-25 18:31:12 +0900265 if (unlikely(rc)) {
Paul Mundt1950f492012-05-10 15:07:53 +0900266 /* Default timeout if invalid */
267 sh_wdt_set_heartbeat(&sh_wdt_dev, WATCHDOG_HEARTBEAT);
268
269 dev_warn(&pdev->dev,
270 "heartbeat value must be 1<=x<=3600, using %d\n",
271 sh_wdt_dev.timeout);
272 }
273
274 dev_info(&pdev->dev, "configured with heartbeat=%d sec (nowayout=%d)\n",
275 sh_wdt_dev.timeout, nowayout);
276
Paul Mundt1950f492012-05-10 15:07:53 +0900277 rc = watchdog_register_device(&sh_wdt_dev);
278 if (unlikely(rc)) {
279 dev_err(&pdev->dev, "Can't register watchdog (err=%d)\n", rc);
Paul Mundtd42c9742012-05-10 16:14:40 +0900280 goto err;
Paul Mundt8f5585e2010-05-25 18:31:12 +0900281 }
282
283 init_timer(&wdt->timer);
284 wdt->timer.function = sh_wdt_ping;
285 wdt->timer.data = (unsigned long)wdt;
286 wdt->timer.expires = next_ping_period(clock_division_ratio);
287
288 platform_set_drvdata(pdev, wdt);
Paul Mundt8f5585e2010-05-25 18:31:12 +0900289
290 dev_info(&pdev->dev, "initialized.\n");
291
Paul Mundt8c013d962012-05-10 16:08:35 +0900292 pm_runtime_enable(&pdev->dev);
293
Paul Mundt8f5585e2010-05-25 18:31:12 +0900294 return 0;
295
Paul Mundtd42c9742012-05-10 16:14:40 +0900296err:
Paul Mundt9ea64042012-05-10 15:46:48 +0900297 clk_put(wdt->clk);
Paul Mundt8f5585e2010-05-25 18:31:12 +0900298
299 return rc;
300}
301
Bill Pemberton4b12b892012-11-19 13:26:24 -0500302static int sh_wdt_remove(struct platform_device *pdev)
Paul Mundt8f5585e2010-05-25 18:31:12 +0900303{
304 struct sh_wdt *wdt = platform_get_drvdata(pdev);
Paul Mundt8f5585e2010-05-25 18:31:12 +0900305
306 platform_set_drvdata(pdev, NULL);
307
Paul Mundt1950f492012-05-10 15:07:53 +0900308 watchdog_unregister_device(&sh_wdt_dev);
Paul Mundt8f5585e2010-05-25 18:31:12 +0900309
Paul Mundt8c013d962012-05-10 16:08:35 +0900310 pm_runtime_disable(&pdev->dev);
Paul Mundt9ea64042012-05-10 15:46:48 +0900311 clk_put(wdt->clk);
Paul Mundt8f5585e2010-05-25 18:31:12 +0900312
313 return 0;
314}
315
Paul Mundt40968122012-05-10 14:21:15 +0900316static void sh_wdt_shutdown(struct platform_device *pdev)
317{
Paul Mundt1950f492012-05-10 15:07:53 +0900318 sh_wdt_stop(&sh_wdt_dev);
Paul Mundt40968122012-05-10 14:21:15 +0900319}
320
Paul Mundt8f5585e2010-05-25 18:31:12 +0900321static struct platform_driver sh_wdt_driver = {
322 .driver = {
323 .name = DRV_NAME,
324 .owner = THIS_MODULE,
325 },
326
Paul Mundt40968122012-05-10 14:21:15 +0900327 .probe = sh_wdt_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500328 .remove = sh_wdt_remove,
Paul Mundt40968122012-05-10 14:21:15 +0900329 .shutdown = sh_wdt_shutdown,
Paul Mundt8f5585e2010-05-25 18:31:12 +0900330};
331
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332static int __init sh_wdt_init(void)
333{
Paul Mundt8f5585e2010-05-25 18:31:12 +0900334 if (unlikely(clock_division_ratio < 0x5 ||
335 clock_division_ratio > 0x7)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 clock_division_ratio = WTCSR_CKS_4096;
Paul Mundt8f5585e2010-05-25 18:31:12 +0900337
Joe Perches27c766a2012-02-15 15:06:19 -0800338 pr_info("divisor must be 0x5<=x<=0x7, using %d\n",
339 clock_division_ratio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 }
341
Paul Mundt8f5585e2010-05-25 18:31:12 +0900342 return platform_driver_register(&sh_wdt_driver);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343}
344
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345static void __exit sh_wdt_exit(void)
346{
Paul Mundt8f5585e2010-05-25 18:31:12 +0900347 platform_driver_unregister(&sh_wdt_driver);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348}
Paul Mundt8f5585e2010-05-25 18:31:12 +0900349module_init(sh_wdt_init);
350module_exit(sh_wdt_exit);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351
352MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
353MODULE_DESCRIPTION("SuperH watchdog driver");
354MODULE_LICENSE("GPL");
Paul Mundt8f5585e2010-05-25 18:31:12 +0900355MODULE_ALIAS("platform:" DRV_NAME);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
357
358module_param(clock_division_ratio, int, 0);
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000359MODULE_PARM_DESC(clock_division_ratio,
360 "Clock division ratio. Valid ranges are from 0x5 (1.31ms) "
Randy Dunlap76550d32010-05-01 09:46:15 -0700361 "to 0x7 (5.25ms). (default=" __MODULE_STRING(WTCSR_CKS_4096) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362
363module_param(heartbeat, int, 0);
Alan Cox70b814e2008-05-19 14:08:55 +0100364MODULE_PARM_DESC(heartbeat,
365 "Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default="
366 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +0100368module_param(nowayout, bool, 0);
Alan Cox70b814e2008-05-19 14:08:55 +0100369MODULE_PARM_DESC(nowayout,
370 "Watchdog cannot be stopped once started (default="
371 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");