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Renaud CERRATOe6bb42e2008-06-23 17:05:49 +02001/*
2 * Watchdog driver for Atmel AT91SAM9x processors.
3 *
4 * Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12/*
13 * The Watchdog Timer Mode Register can be only written to once. If the
14 * timeout need to be set from Linux, be sure that the bootstrap or the
15 * bootloader doesn't write to this register.
16 */
17
Joe Perches27c766a2012-02-15 15:06:19 -080018#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020020#include <linux/errno.h>
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020021#include <linux/init.h>
Boris BREZILLON5161b312013-10-04 09:24:12 +020022#include <linux/interrupt.h>
Andrew Victor2af29b72009-02-11 21:23:10 +010023#include <linux/io.h>
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020024#include <linux/kernel.h>
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020025#include <linux/module.h>
26#include <linux/moduleparam.h>
27#include <linux/platform_device.h>
Boris BREZILLON5161b312013-10-04 09:24:12 +020028#include <linux/reboot.h>
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020029#include <linux/types.h>
30#include <linux/watchdog.h>
31#include <linux/jiffies.h>
32#include <linux/timer.h>
33#include <linux/bitops.h>
34#include <linux/uaccess.h>
Fabio Porceddabe49bba2012-11-12 09:37:25 +010035#include <linux/of.h>
Boris BREZILLON5161b312013-10-04 09:24:12 +020036#include <linux/of_irq.h>
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020037
Jean-Christophe Plagniol-Villarde7b39142011-07-15 01:52:05 +020038#include "at91sam9_wdt.h"
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020039
40#define DRV_NAME "AT91SAM9 Watchdog"
41
Boris BREZILLON5161b312013-10-04 09:24:12 +020042#define wdt_read(wdt, field) \
43 __raw_readl((wdt)->base + (field))
44#define wdt_write(wtd, field, val) \
45 __raw_writel((val), (wdt)->base + (field))
Jean-Christophe PLAGNIOL-VILLARDc1c30a22011-11-02 01:43:31 +080046
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020047/* AT91SAM9 watchdog runs a 12bit counter @ 256Hz,
48 * use this to convert a watchdog
49 * value from/to milliseconds.
50 */
Boris BREZILLON5161b312013-10-04 09:24:12 +020051#define ticks_to_hz_rounddown(t) ((((t) + 1) * HZ) >> 8)
52#define ticks_to_hz_roundup(t) (((((t) + 1) * HZ) + 255) >> 8)
53#define ticks_to_secs(t) (((t) + 1) >> 8)
Boris BREZILLON14447972013-11-03 18:52:42 +010054#define secs_to_ticks(s) ((s) ? (((s) << 8) - 1) : 0)
Boris BREZILLON5161b312013-10-04 09:24:12 +020055
56#define WDT_MR_RESET 0x3FFF2FFF
57
58/* Watchdog max counter value in ticks */
59#define WDT_COUNTER_MAX_TICKS 0xFFF
60
61/* Watchdog max delta/value in secs */
62#define WDT_COUNTER_MAX_SECS ticks_to_secs(WDT_COUNTER_MAX_TICKS)
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020063
64/* Hardware timeout in seconds */
65#define WDT_HW_TIMEOUT 2
66
67/* Timer heartbeat (500ms) */
68#define WDT_TIMEOUT (HZ/2)
69
70/* User land timeout */
71#define WDT_HEARTBEAT 15
Fabio Porceddac1fd5f62013-02-14 09:14:25 +010072static int heartbeat;
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020073module_param(heartbeat, int, 0);
74MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
75 "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
76
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010077static bool nowayout = WATCHDOG_NOWAYOUT;
78module_param(nowayout, bool, 0);
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020079MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
80 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
81
Boris BREZILLON5161b312013-10-04 09:24:12 +020082#define to_wdt(wdd) container_of(wdd, struct at91wdt, wdd)
83struct at91wdt {
84 struct watchdog_device wdd;
Jean-Christophe PLAGNIOL-VILLARDc1c30a22011-11-02 01:43:31 +080085 void __iomem *base;
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020086 unsigned long next_heartbeat; /* the next_heartbeat for the timer */
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020087 struct timer_list timer; /* The timer that pings the watchdog */
Boris BREZILLON5161b312013-10-04 09:24:12 +020088 u32 mr;
89 u32 mr_mask;
90 unsigned long heartbeat; /* WDT heartbeat in jiffies */
91 bool nowayout;
92 unsigned int irq;
93};
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +020094
95/* ......................................................................... */
96
Boris BREZILLON5161b312013-10-04 09:24:12 +020097static irqreturn_t wdt_interrupt(int irq, void *dev_id)
98{
99 struct at91wdt *wdt = (struct at91wdt *)dev_id;
100
101 if (wdt_read(wdt, AT91_WDT_SR)) {
102 pr_crit("at91sam9 WDT software reset\n");
103 emergency_restart();
104 pr_crit("Reboot didn't ?????\n");
105 }
106
107 return IRQ_HANDLED;
108}
109
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200110/*
111 * Reload the watchdog timer. (ie, pat the watchdog)
112 */
Boris BREZILLON5161b312013-10-04 09:24:12 +0200113static inline void at91_wdt_reset(struct at91wdt *wdt)
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200114{
Boris BREZILLON5161b312013-10-04 09:24:12 +0200115 wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200116}
117
118/*
119 * Timer tick
120 */
121static void at91_ping(unsigned long data)
122{
Boris BREZILLON5161b312013-10-04 09:24:12 +0200123 struct at91wdt *wdt = (struct at91wdt *)data;
124 if (time_before(jiffies, wdt->next_heartbeat) ||
125 !watchdog_active(&wdt->wdd)) {
126 at91_wdt_reset(wdt);
127 mod_timer(&wdt->timer, jiffies + wdt->heartbeat);
128 } else {
Joe Perches27c766a2012-02-15 15:06:19 -0800129 pr_crit("I will reset your machine !\n");
Boris BREZILLON5161b312013-10-04 09:24:12 +0200130 }
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200131}
132
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800133static int at91_wdt_start(struct watchdog_device *wdd)
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200134{
Boris BREZILLON5161b312013-10-04 09:24:12 +0200135 struct at91wdt *wdt = to_wdt(wdd);
136 /* calculate when the next userspace timeout will be */
137 wdt->next_heartbeat = jiffies + wdd->timeout * HZ;
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800138 return 0;
139}
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200140
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800141static int at91_wdt_stop(struct watchdog_device *wdd)
142{
143 /* The watchdog timer hardware can not be stopped... */
144 return 0;
145}
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200146
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800147static int at91_wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_timeout)
148{
149 wdd->timeout = new_timeout;
Boris BREZILLON5161b312013-10-04 09:24:12 +0200150 return at91_wdt_start(wdd);
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200151}
152
Boris BREZILLON5161b312013-10-04 09:24:12 +0200153static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt)
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200154{
Boris BREZILLON5161b312013-10-04 09:24:12 +0200155 u32 tmp;
156 u32 delta;
157 u32 value;
158 int err;
159 u32 mask = wdt->mr_mask;
160 unsigned long min_heartbeat = 1;
Boris BREZILLONf72fa002013-11-03 18:52:44 +0100161 unsigned long max_heartbeat;
Boris BREZILLON5161b312013-10-04 09:24:12 +0200162 struct device *dev = &pdev->dev;
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200163
Boris BREZILLON5161b312013-10-04 09:24:12 +0200164 tmp = wdt_read(wdt, AT91_WDT_MR);
165 if ((tmp & mask) != (wdt->mr & mask)) {
166 if (tmp == WDT_MR_RESET) {
167 wdt_write(wdt, AT91_WDT_MR, wdt->mr);
168 tmp = wdt_read(wdt, AT91_WDT_MR);
169 }
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200170 }
171
Boris BREZILLON5161b312013-10-04 09:24:12 +0200172 if (tmp & AT91_WDT_WDDIS) {
173 if (wdt->mr & AT91_WDT_WDDIS)
174 return 0;
175 dev_err(dev, "watchdog is disabled\n");
176 return -EINVAL;
177 }
178
179 value = tmp & AT91_WDT_WDV;
180 delta = (tmp & AT91_WDT_WDD) >> 16;
181
182 if (delta < value)
183 min_heartbeat = ticks_to_hz_roundup(value - delta);
184
Boris BREZILLONf72fa002013-11-03 18:52:44 +0100185 max_heartbeat = ticks_to_hz_rounddown(value);
186 if (!max_heartbeat) {
Boris BREZILLON5161b312013-10-04 09:24:12 +0200187 dev_err(dev,
188 "heartbeat is too small for the system to handle it correctly\n");
189 return -EINVAL;
190 }
191
Boris BREZILLONf72fa002013-11-03 18:52:44 +0100192 /*
193 * Try to reset the watchdog counter 4 or 2 times more often than
194 * actually requested, to avoid spurious watchdog reset.
195 * If this is not possible because of the min_heartbeat value, reset
196 * it at the min_heartbeat period.
197 */
198 if ((max_heartbeat / 4) >= min_heartbeat)
199 wdt->heartbeat = max_heartbeat / 4;
200 else if ((max_heartbeat / 2) >= min_heartbeat)
201 wdt->heartbeat = max_heartbeat / 2;
202 else
Boris BREZILLON5161b312013-10-04 09:24:12 +0200203 wdt->heartbeat = min_heartbeat;
Boris BREZILLONf72fa002013-11-03 18:52:44 +0100204
205 if (max_heartbeat < min_heartbeat + 4)
Boris BREZILLON5161b312013-10-04 09:24:12 +0200206 dev_warn(dev,
207 "min heartbeat and max heartbeat might be too close for the system to handle it correctly\n");
Boris BREZILLON5161b312013-10-04 09:24:12 +0200208
209 if ((tmp & AT91_WDT_WDFIEN) && wdt->irq) {
210 err = request_irq(wdt->irq, wdt_interrupt,
211 IRQF_SHARED | IRQF_IRQPOLL,
212 pdev->name, wdt);
213 if (err)
214 return err;
215 }
216
217 if ((tmp & wdt->mr_mask) != (wdt->mr & wdt->mr_mask))
218 dev_warn(dev,
219 "watchdog already configured differently (mr = %x expecting %x)\n",
220 tmp & wdt->mr_mask, wdt->mr & wdt->mr_mask);
221
222 setup_timer(&wdt->timer, at91_ping, (unsigned long)wdt);
Boris BREZILLONa04c3f02013-11-03 18:52:43 +0100223
224 /*
225 * Use min_heartbeat the first time to avoid spurious watchdog reset:
226 * we don't know for how long the watchdog counter is running, and
227 * - resetting it right now might trigger a watchdog fault reset
228 * - waiting for heartbeat time might lead to a watchdog timeout
229 * reset
230 */
231 mod_timer(&wdt->timer, jiffies + min_heartbeat);
Boris BREZILLON5161b312013-10-04 09:24:12 +0200232
233 /* Try to set timeout from device tree first */
234 if (watchdog_init_timeout(&wdt->wdd, 0, dev))
235 watchdog_init_timeout(&wdt->wdd, heartbeat, dev);
236 watchdog_set_nowayout(&wdt->wdd, wdt->nowayout);
237 err = watchdog_register_device(&wdt->wdd);
238 if (err)
239 goto out_stop_timer;
240
241 wdt->next_heartbeat = jiffies + wdt->wdd.timeout * HZ;
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200242
243 return 0;
Boris BREZILLON5161b312013-10-04 09:24:12 +0200244
245out_stop_timer:
246 del_timer(&wdt->timer);
247 return err;
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200248}
249
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800250/* ......................................................................... */
251
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200252static const struct watchdog_info at91_wdt_info = {
253 .identity = DRV_NAME,
Wim Van Sebroecke73a7802009-05-11 18:33:00 +0000254 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
255 WDIOF_MAGICCLOSE,
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200256};
257
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800258static const struct watchdog_ops at91_wdt_ops = {
259 .owner = THIS_MODULE,
260 .start = at91_wdt_start,
261 .stop = at91_wdt_stop,
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800262 .set_timeout = at91_wdt_set_timeout,
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200263};
264
Boris BREZILLON5161b312013-10-04 09:24:12 +0200265#if defined(CONFIG_OF)
266static int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt)
267{
268 u32 min = 0;
269 u32 max = WDT_COUNTER_MAX_SECS;
270 const char *tmp;
271
272 /* Get the interrupts property */
273 wdt->irq = irq_of_parse_and_map(np, 0);
274 if (!wdt->irq)
275 dev_warn(wdt->wdd.parent, "failed to get IRQ from DT\n");
276
277 if (!of_property_read_u32_index(np, "atmel,max-heartbeat-sec", 0,
278 &max)) {
279 if (!max || max > WDT_COUNTER_MAX_SECS)
280 max = WDT_COUNTER_MAX_SECS;
281
282 if (!of_property_read_u32_index(np, "atmel,min-heartbeat-sec",
283 0, &min)) {
284 if (min >= max)
285 min = max - 1;
286 }
287 }
288
289 min = secs_to_ticks(min);
290 max = secs_to_ticks(max);
291
292 wdt->mr_mask = 0x3FFFFFFF;
293 wdt->mr = 0;
294 if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
295 !strcmp(tmp, "software")) {
296 wdt->mr |= AT91_WDT_WDFIEN;
297 wdt->mr_mask &= ~AT91_WDT_WDRPROC;
298 } else {
299 wdt->mr |= AT91_WDT_WDRSTEN;
300 }
301
302 if (!of_property_read_string(np, "atmel,reset-type", &tmp) &&
303 !strcmp(tmp, "proc"))
304 wdt->mr |= AT91_WDT_WDRPROC;
305
306 if (of_property_read_bool(np, "atmel,disable")) {
307 wdt->mr |= AT91_WDT_WDDIS;
308 wdt->mr_mask &= AT91_WDT_WDDIS;
309 }
310
311 if (of_property_read_bool(np, "atmel,idle-halt"))
312 wdt->mr |= AT91_WDT_WDIDLEHLT;
313
314 if (of_property_read_bool(np, "atmel,dbg-halt"))
315 wdt->mr |= AT91_WDT_WDDBGHLT;
316
317 wdt->mr |= max | ((max - min) << 16);
318
319 return 0;
320}
321#else
322static inline int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt)
323{
324 return 0;
325}
326#endif
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200327
328static int __init at91wdt_probe(struct platform_device *pdev)
329{
Jean-Christophe PLAGNIOL-VILLARDc1c30a22011-11-02 01:43:31 +0800330 struct resource *r;
Boris BREZILLON5161b312013-10-04 09:24:12 +0200331 int err;
332 struct at91wdt *wdt;
333
334 wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
335 if (!wdt)
336 return -ENOMEM;
337
338 wdt->mr = (WDT_HW_TIMEOUT * 256) | AT91_WDT_WDRSTEN | AT91_WDT_WDD |
339 AT91_WDT_WDDBGHLT | AT91_WDT_WDIDLEHLT;
340 wdt->mr_mask = 0x3FFFFFFF;
341 wdt->nowayout = nowayout;
342 wdt->wdd.parent = &pdev->dev;
343 wdt->wdd.info = &at91_wdt_info;
344 wdt->wdd.ops = &at91_wdt_ops;
345 wdt->wdd.timeout = WDT_HEARTBEAT;
346 wdt->wdd.min_timeout = 1;
347 wdt->wdd.max_timeout = 0xFFFF;
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200348
Jean-Christophe PLAGNIOL-VILLARDc1c30a22011-11-02 01:43:31 +0800349 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Boris BREZILLON5161b312013-10-04 09:24:12 +0200350 wdt->base = devm_ioremap_resource(&pdev->dev, r);
351 if (IS_ERR(wdt->base))
352 return PTR_ERR(wdt->base);
353
354 if (pdev->dev.of_node) {
355 err = of_at91wdt_init(pdev->dev.of_node, wdt);
356 if (err)
357 return err;
Jean-Christophe PLAGNIOL-VILLARDc1c30a22011-11-02 01:43:31 +0800358 }
359
Boris BREZILLON5161b312013-10-04 09:24:12 +0200360 err = at91_wdt_init(pdev, wdt);
361 if (err)
362 return err;
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800363
Boris BREZILLON5161b312013-10-04 09:24:12 +0200364 platform_set_drvdata(pdev, wdt);
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200365
Joe Perches27c766a2012-02-15 15:06:19 -0800366 pr_info("enabled (heartbeat=%d sec, nowayout=%d)\n",
Boris BREZILLON5161b312013-10-04 09:24:12 +0200367 wdt->wdd.timeout, wdt->nowayout);
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200368
369 return 0;
370}
371
372static int __exit at91wdt_remove(struct platform_device *pdev)
373{
Boris BREZILLON5161b312013-10-04 09:24:12 +0200374 struct at91wdt *wdt = platform_get_drvdata(pdev);
375 watchdog_unregister_device(&wdt->wdd);
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200376
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800377 pr_warn("I quit now, hardware will probably reboot!\n");
Boris BREZILLON5161b312013-10-04 09:24:12 +0200378 del_timer(&wdt->timer);
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200379
Wenyou Yang490ac7af2013-02-01 15:06:21 +0800380 return 0;
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200381}
382
Fabio Porceddabe49bba2012-11-12 09:37:25 +0100383#if defined(CONFIG_OF)
Arnd Bergmann6c41e472013-01-25 14:14:27 +0000384static const struct of_device_id at91_wdt_dt_ids[] = {
Fabio Porceddabe49bba2012-11-12 09:37:25 +0100385 { .compatible = "atmel,at91sam9260-wdt" },
386 { /* sentinel */ }
387};
388
389MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
390#endif
391
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200392static struct platform_driver at91wdt_driver = {
393 .remove = __exit_p(at91wdt_remove),
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200394 .driver = {
395 .name = "at91_wdt",
Fabio Porceddabe49bba2012-11-12 09:37:25 +0100396 .of_match_table = of_match_ptr(at91_wdt_dt_ids),
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200397 },
398};
399
Fabio Porcedda1cb92042013-01-09 12:15:27 +0100400module_platform_driver_probe(at91wdt_driver, at91wdt_probe);
Renaud CERRATOe6bb42e2008-06-23 17:05:49 +0200401
402MODULE_AUTHOR("Renaud CERRATO <r.cerrato@til-technologies.fr>");
403MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors");
404MODULE_LICENSE("GPL");