blob: 6ea0634345e99512eefec4f82ebcd8ee348bac82 [file] [log] [blame]
Jamie Ilesc9353ae2011-01-24 12:19:12 +00001/*
2 * Copyright 2010-2011 Picochip Ltd., Jamie Iles
3 * http://www.picochip.com
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
9 *
10 * This file implements a driver for the Synopsys DesignWare watchdog device
Baruch Siach58a251f2013-12-30 14:25:54 +020011 * in the many subsystems. The watchdog has 16 different timeout periods
Jamie Ilesc9353ae2011-01-24 12:19:12 +000012 * and these are a function of the input clock frequency.
13 *
14 * The DesignWare watchdog cannot be stopped once it has been started so we
15 * use a software timer to implement a ping that will keep the watchdog alive.
16 * If we receive an expected close for the watchdog then we keep the timer
17 * running, otherwise the timer is stopped and the watchdog will expire.
18 */
Joe Perches27c766a2012-02-15 15:06:19 -080019
20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
Jamie Ilesc9353ae2011-01-24 12:19:12 +000021
22#include <linux/bitops.h>
23#include <linux/clk.h>
Jisheng Zhang31228f42014-09-23 15:42:12 +080024#include <linux/delay.h>
Jamie Ilesc9353ae2011-01-24 12:19:12 +000025#include <linux/device.h>
26#include <linux/err.h>
27#include <linux/fs.h>
28#include <linux/io.h>
29#include <linux/kernel.h>
30#include <linux/miscdevice.h>
31#include <linux/module.h>
32#include <linux/moduleparam.h>
Jisheng Zhang31228f42014-09-23 15:42:12 +080033#include <linux/notifier.h>
Dinh Nguyen58e56372013-10-22 11:59:12 -050034#include <linux/of.h>
Jamie Ilesc9353ae2011-01-24 12:19:12 +000035#include <linux/pm.h>
36#include <linux/platform_device.h>
Jisheng Zhang31228f42014-09-23 15:42:12 +080037#include <linux/reboot.h>
Jamie Ilesc9353ae2011-01-24 12:19:12 +000038#include <linux/timer.h>
39#include <linux/uaccess.h>
40#include <linux/watchdog.h>
41
42#define WDOG_CONTROL_REG_OFFSET 0x00
43#define WDOG_CONTROL_REG_WDT_EN_MASK 0x01
44#define WDOG_TIMEOUT_RANGE_REG_OFFSET 0x04
Jisheng Zhangdfa07142014-09-23 15:42:11 +080045#define WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT 4
Jamie Ilesc9353ae2011-01-24 12:19:12 +000046#define WDOG_CURRENT_COUNT_REG_OFFSET 0x08
47#define WDOG_COUNTER_RESTART_REG_OFFSET 0x0c
48#define WDOG_COUNTER_RESTART_KICK_VALUE 0x76
49
50/* The maximum TOP (timeout period) value that can be set in the watchdog. */
51#define DW_WDT_MAX_TOP 15
52
Doug Andersonb5ade9b2015-01-27 14:25:17 -080053#define DW_WDT_DEFAULT_SECONDS 30
54
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010055static bool nowayout = WATCHDOG_NOWAYOUT;
56module_param(nowayout, bool, 0);
Jamie Ilesc9353ae2011-01-24 12:19:12 +000057MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
58 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
59
60#define WDT_TIMEOUT (HZ / 2)
61
62static struct {
Jamie Ilesc9353ae2011-01-24 12:19:12 +000063 void __iomem *regs;
64 struct clk *clk;
65 unsigned long in_use;
66 unsigned long next_heartbeat;
67 struct timer_list timer;
68 int expect_close;
Jisheng Zhang31228f42014-09-23 15:42:12 +080069 struct notifier_block restart_handler;
Jamie Ilesc9353ae2011-01-24 12:19:12 +000070} dw_wdt;
71
72static inline int dw_wdt_is_enabled(void)
73{
74 return readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET) &
75 WDOG_CONTROL_REG_WDT_EN_MASK;
76}
77
78static inline int dw_wdt_top_in_seconds(unsigned top)
79{
80 /*
81 * There are 16 possible timeout values in 0..15 where the number of
82 * cycles is 2 ^ (16 + i) and the watchdog counts down.
83 */
84 return (1 << (16 + top)) / clk_get_rate(dw_wdt.clk);
85}
86
87static int dw_wdt_get_top(void)
88{
89 int top = readl(dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF;
90
91 return dw_wdt_top_in_seconds(top);
92}
93
94static inline void dw_wdt_set_next_heartbeat(void)
95{
96 dw_wdt.next_heartbeat = jiffies + dw_wdt_get_top() * HZ;
97}
98
Doug Andersona0085012015-01-27 14:25:16 -080099static void dw_wdt_keepalive(void)
100{
101 writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs +
102 WDOG_COUNTER_RESTART_REG_OFFSET);
103}
104
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000105static int dw_wdt_set_top(unsigned top_s)
106{
107 int i, top_val = DW_WDT_MAX_TOP;
108
109 /*
110 * Iterate over the timeout values until we find the closest match. We
111 * always look for >=.
112 */
113 for (i = 0; i <= DW_WDT_MAX_TOP; ++i)
114 if (dw_wdt_top_in_seconds(i) >= top_s) {
115 top_val = i;
116 break;
117 }
118
Doug Andersona0085012015-01-27 14:25:16 -0800119 /*
120 * Set the new value in the watchdog. Some versions of dw_wdt
121 * have have TOPINIT in the TIMEOUT_RANGE register (as per
122 * CP_WDT_DUAL_TOP in WDT_COMP_PARAMS_1). On those we
123 * effectively get a pat of the watchdog right here.
124 */
Jisheng Zhangdfa07142014-09-23 15:42:11 +0800125 writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
126 dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000127
Doug Andersona0085012015-01-27 14:25:16 -0800128 /*
129 * Add an explicit pat to handle versions of the watchdog that
130 * don't have TOPINIT. This won't hurt on versions that have
131 * it.
132 */
133 dw_wdt_keepalive();
134
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000135 dw_wdt_set_next_heartbeat();
136
137 return dw_wdt_top_in_seconds(top_val);
138}
139
Jisheng Zhang31228f42014-09-23 15:42:12 +0800140static int dw_wdt_restart_handle(struct notifier_block *this,
141 unsigned long mode, void *cmd)
142{
143 u32 val;
144
145 writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
146 val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
147 if (val & WDOG_CONTROL_REG_WDT_EN_MASK)
148 writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs +
149 WDOG_COUNTER_RESTART_REG_OFFSET);
150 else
151 writel(WDOG_CONTROL_REG_WDT_EN_MASK,
152 dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
153
154 /* wait for reset to assert... */
155 mdelay(500);
156
157 return NOTIFY_DONE;
158}
159
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000160static void dw_wdt_ping(unsigned long data)
161{
162 if (time_before(jiffies, dw_wdt.next_heartbeat) ||
163 (!nowayout && !dw_wdt.in_use)) {
164 dw_wdt_keepalive();
165 mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
166 } else
167 pr_crit("keepalive missed, machine will reset\n");
168}
169
170static int dw_wdt_open(struct inode *inode, struct file *filp)
171{
172 if (test_and_set_bit(0, &dw_wdt.in_use))
173 return -EBUSY;
174
175 /* Make sure we don't get unloaded. */
176 __module_get(THIS_MODULE);
177
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000178 if (!dw_wdt_is_enabled()) {
179 /*
180 * The watchdog is not currently enabled. Set the timeout to
Doug Andersonb5ade9b2015-01-27 14:25:17 -0800181 * something reasonable and then start it.
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000182 */
Doug Andersonb5ade9b2015-01-27 14:25:17 -0800183 dw_wdt_set_top(DW_WDT_DEFAULT_SECONDS);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000184 writel(WDOG_CONTROL_REG_WDT_EN_MASK,
185 dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
186 }
187
188 dw_wdt_set_next_heartbeat();
189
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000190 return nonseekable_open(inode, filp);
191}
192
Sachin Kamat0b930262013-05-14 12:11:03 +0530193static ssize_t dw_wdt_write(struct file *filp, const char __user *buf,
194 size_t len, loff_t *offset)
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000195{
196 if (!len)
197 return 0;
198
199 if (!nowayout) {
200 size_t i;
201
202 dw_wdt.expect_close = 0;
203
204 for (i = 0; i < len; ++i) {
205 char c;
206
207 if (get_user(c, buf + i))
208 return -EFAULT;
209
210 if (c == 'V') {
211 dw_wdt.expect_close = 1;
212 break;
213 }
214 }
215 }
216
217 dw_wdt_set_next_heartbeat();
Doug Anderson04b1a622015-05-07 21:27:45 -0700218 dw_wdt_keepalive();
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000219 mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
220
221 return len;
222}
223
224static u32 dw_wdt_time_left(void)
225{
226 return readl(dw_wdt.regs + WDOG_CURRENT_COUNT_REG_OFFSET) /
227 clk_get_rate(dw_wdt.clk);
228}
229
230static const struct watchdog_info dw_wdt_ident = {
231 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
232 WDIOF_MAGICCLOSE,
233 .identity = "Synopsys DesignWare Watchdog",
234};
235
236static long dw_wdt_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
237{
238 unsigned long val;
239 int timeout;
240
241 switch (cmd) {
242 case WDIOC_GETSUPPORT:
Jingoo Han60295502013-08-01 14:38:36 +0900243 return copy_to_user((void __user *)arg, &dw_wdt_ident,
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000244 sizeof(dw_wdt_ident)) ? -EFAULT : 0;
245
246 case WDIOC_GETSTATUS:
247 case WDIOC_GETBOOTSTATUS:
Jingoo Han60295502013-08-01 14:38:36 +0900248 return put_user(0, (int __user *)arg);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000249
250 case WDIOC_KEEPALIVE:
251 dw_wdt_set_next_heartbeat();
252 return 0;
253
254 case WDIOC_SETTIMEOUT:
255 if (get_user(val, (int __user *)arg))
256 return -EFAULT;
257 timeout = dw_wdt_set_top(val);
258 return put_user(timeout , (int __user *)arg);
259
260 case WDIOC_GETTIMEOUT:
261 return put_user(dw_wdt_get_top(), (int __user *)arg);
262
263 case WDIOC_GETTIMELEFT:
264 /* Get the time left until expiry. */
265 if (get_user(val, (int __user *)arg))
266 return -EFAULT;
267 return put_user(dw_wdt_time_left(), (int __user *)arg);
268
269 default:
270 return -ENOTTY;
271 }
272}
273
274static int dw_wdt_release(struct inode *inode, struct file *filp)
275{
276 clear_bit(0, &dw_wdt.in_use);
277
278 if (!dw_wdt.expect_close) {
279 del_timer(&dw_wdt.timer);
280
281 if (!nowayout)
282 pr_crit("unexpected close, system will reboot soon\n");
283 else
284 pr_crit("watchdog cannot be disabled, system will reboot soon\n");
285 }
286
287 dw_wdt.expect_close = 0;
288
289 return 0;
290}
291
Heiko Stübnerad83c6c2013-06-26 20:03:52 +0200292#ifdef CONFIG_PM_SLEEP
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000293static int dw_wdt_suspend(struct device *dev)
294{
Heiko Stübner280103e2013-06-26 20:04:31 +0200295 clk_disable_unprepare(dw_wdt.clk);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000296
297 return 0;
298}
299
300static int dw_wdt_resume(struct device *dev)
301{
Heiko Stübner280103e2013-06-26 20:04:31 +0200302 int err = clk_prepare_enable(dw_wdt.clk);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000303
304 if (err)
305 return err;
306
307 dw_wdt_keepalive();
308
309 return 0;
310}
Heiko Stübnerad83c6c2013-06-26 20:03:52 +0200311#endif /* CONFIG_PM_SLEEP */
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000312
Heiko Stübnerad83c6c2013-06-26 20:03:52 +0200313static SIMPLE_DEV_PM_OPS(dw_wdt_pm_ops, dw_wdt_suspend, dw_wdt_resume);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000314
315static const struct file_operations wdt_fops = {
316 .owner = THIS_MODULE,
317 .llseek = no_llseek,
318 .open = dw_wdt_open,
319 .write = dw_wdt_write,
320 .unlocked_ioctl = dw_wdt_ioctl,
321 .release = dw_wdt_release
322};
323
324static struct miscdevice dw_wdt_miscdev = {
325 .fops = &wdt_fops,
326 .name = "watchdog",
327 .minor = WATCHDOG_MINOR,
328};
329
Bill Pemberton2d991a12012-11-19 13:21:41 -0500330static int dw_wdt_drv_probe(struct platform_device *pdev)
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000331{
332 int ret;
333 struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
334
Thierry Reding4c271bb2013-01-21 11:09:25 +0100335 dw_wdt.regs = devm_ioremap_resource(&pdev->dev, mem);
336 if (IS_ERR(dw_wdt.regs))
337 return PTR_ERR(dw_wdt.regs);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000338
Jingoo Hancf3cc8c2013-04-29 18:15:26 +0900339 dw_wdt.clk = devm_clk_get(&pdev->dev, NULL);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000340 if (IS_ERR(dw_wdt.clk))
341 return PTR_ERR(dw_wdt.clk);
342
Heiko Stübner280103e2013-06-26 20:04:31 +0200343 ret = clk_prepare_enable(dw_wdt.clk);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000344 if (ret)
Jingoo Hancf3cc8c2013-04-29 18:15:26 +0900345 return ret;
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000346
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000347 ret = misc_register(&dw_wdt_miscdev);
348 if (ret)
349 goto out_disable_clk;
350
Jisheng Zhang31228f42014-09-23 15:42:12 +0800351 dw_wdt.restart_handler.notifier_call = dw_wdt_restart_handle;
352 dw_wdt.restart_handler.priority = 128;
353 ret = register_restart_handler(&dw_wdt.restart_handler);
354 if (ret)
355 pr_warn("cannot register restart handler\n");
356
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000357 dw_wdt_set_next_heartbeat();
358 setup_timer(&dw_wdt.timer, dw_wdt_ping, 0);
359 mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
360
361 return 0;
362
363out_disable_clk:
Heiko Stübner280103e2013-06-26 20:04:31 +0200364 clk_disable_unprepare(dw_wdt.clk);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000365
366 return ret;
367}
368
Bill Pemberton4b12b892012-11-19 13:26:24 -0500369static int dw_wdt_drv_remove(struct platform_device *pdev)
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000370{
Jisheng Zhang31228f42014-09-23 15:42:12 +0800371 unregister_restart_handler(&dw_wdt.restart_handler);
372
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000373 misc_deregister(&dw_wdt_miscdev);
374
Heiko Stübner280103e2013-06-26 20:04:31 +0200375 clk_disable_unprepare(dw_wdt.clk);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000376
377 return 0;
378}
379
Dinh Nguyen58e56372013-10-22 11:59:12 -0500380#ifdef CONFIG_OF
381static const struct of_device_id dw_wdt_of_match[] = {
382 { .compatible = "snps,dw-wdt", },
383 { /* sentinel */ }
384};
385MODULE_DEVICE_TABLE(of, dw_wdt_of_match);
386#endif
387
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000388static struct platform_driver dw_wdt_driver = {
389 .probe = dw_wdt_drv_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500390 .remove = dw_wdt_drv_remove,
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000391 .driver = {
392 .name = "dw_wdt",
Dinh Nguyen58e56372013-10-22 11:59:12 -0500393 .of_match_table = of_match_ptr(dw_wdt_of_match),
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000394 .pm = &dw_wdt_pm_ops,
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000395 },
396};
397
Axel Linb8ec6112011-11-29 13:56:27 +0800398module_platform_driver(dw_wdt_driver);
Jamie Ilesc9353ae2011-01-24 12:19:12 +0000399
400MODULE_AUTHOR("Jamie Iles");
401MODULE_DESCRIPTION("Synopsys DesignWare Watchdog Driver");
402MODULE_LICENSE("GPL");