1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * omap_wdt.c
4 *
5 * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
6 *
7 * Author: MontaVista Software, Inc.
8 * <gdavis@mvista.com> or <source@mvista.com>
9 *
10 * 2003 (c) MontaVista Software, Inc.
11 *
12 * History:
13 *
14 * 20030527: George G. Davis <gdavis@mvista.com>
15 * Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
16 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
17 * Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
18 *
19 * Copyright (c) 2004 Texas Instruments.
20 * 1. Modified to support OMAP1610 32-KHz watchdog timer
21 * 2. Ported to 2.6 kernel
22 *
23 * Copyright (c) 2005 David Brownell
24 * Use the driver model and standard identifiers; handle bigger timeouts.
25 */
26
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
29 #include <linux/module.h>
30 #include <linux/mod_devicetable.h>
31 #include <linux/types.h>
32 #include <linux/kernel.h>
33 #include <linux/mm.h>
34 #include <linux/watchdog.h>
35 #include <linux/reboot.h>
36 #include <linux/err.h>
37 #include <linux/platform_device.h>
38 #include <linux/moduleparam.h>
39 #include <linux/io.h>
40 #include <linux/slab.h>
41 #include <linux/pm_runtime.h>
42 #include <linux/platform_data/omap-wd-timer.h>
43
44 #include "omap_wdt.h"
45
46 static bool nowayout = WATCHDOG_NOWAYOUT;
47 module_param(nowayout, bool, 0);
48 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
49 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
50
51 static unsigned timer_margin;
52 module_param(timer_margin, uint, 0);
53 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
54
55 #define to_omap_wdt_dev(_wdog) container_of(_wdog, struct omap_wdt_dev, wdog)
56
57 static bool early_enable;
58 module_param(early_enable, bool, 0);
59 MODULE_PARM_DESC(early_enable,
60 "Watchdog is started on module insertion (default=0)");
61
62 struct omap_wdt_dev {
63 struct watchdog_device wdog;
64 void __iomem *base; /* physical */
65 struct device *dev;
66 bool omap_wdt_users;
67 int wdt_trgr_pattern;
68 struct mutex lock; /* to avoid races with PM */
69 };
70
omap_wdt_reload(struct omap_wdt_dev * wdev)71 static void omap_wdt_reload(struct omap_wdt_dev *wdev)
72 {
73 void __iomem *base = wdev->base;
74
75 /* wait for posted write to complete */
76 while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08)
77 cpu_relax();
78
79 wdev->wdt_trgr_pattern = ~wdev->wdt_trgr_pattern;
80 writel_relaxed(wdev->wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
81
82 /* wait for posted write to complete */
83 while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08)
84 cpu_relax();
85 /* reloaded WCRR from WLDR */
86 }
87
omap_wdt_enable(struct omap_wdt_dev * wdev)88 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
89 {
90 void __iomem *base = wdev->base;
91
92 /* Sequence to enable the watchdog */
93 writel_relaxed(0xBBBB, base + OMAP_WATCHDOG_SPR);
94 while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10)
95 cpu_relax();
96
97 writel_relaxed(0x4444, base + OMAP_WATCHDOG_SPR);
98 while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10)
99 cpu_relax();
100 }
101
omap_wdt_disable(struct omap_wdt_dev * wdev)102 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
103 {
104 void __iomem *base = wdev->base;
105
106 /* sequence required to disable watchdog */
107 writel_relaxed(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
108 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10)
109 cpu_relax();
110
111 writel_relaxed(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
112 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10)
113 cpu_relax();
114 }
115
omap_wdt_set_timer(struct omap_wdt_dev * wdev,unsigned int timeout)116 static void omap_wdt_set_timer(struct omap_wdt_dev *wdev,
117 unsigned int timeout)
118 {
119 u32 pre_margin = GET_WLDR_VAL(timeout);
120 void __iomem *base = wdev->base;
121
122 /* just count up at 32 KHz */
123 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04)
124 cpu_relax();
125
126 writel_relaxed(pre_margin, base + OMAP_WATCHDOG_LDR);
127 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04)
128 cpu_relax();
129 }
130
omap_wdt_start(struct watchdog_device * wdog)131 static int omap_wdt_start(struct watchdog_device *wdog)
132 {
133 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
134 void __iomem *base = wdev->base;
135
136 mutex_lock(&wdev->lock);
137
138 wdev->omap_wdt_users = true;
139
140 pm_runtime_get_sync(wdev->dev);
141
142 /*
143 * Make sure the watchdog is disabled. This is unfortunately required
144 * because writing to various registers with the watchdog running has no
145 * effect.
146 */
147 omap_wdt_disable(wdev);
148
149 /* initialize prescaler */
150 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01)
151 cpu_relax();
152
153 writel_relaxed((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
154 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01)
155 cpu_relax();
156
157 omap_wdt_set_timer(wdev, wdog->timeout);
158 omap_wdt_reload(wdev); /* trigger loading of new timeout value */
159 omap_wdt_enable(wdev);
160
161 mutex_unlock(&wdev->lock);
162
163 return 0;
164 }
165
omap_wdt_stop(struct watchdog_device * wdog)166 static int omap_wdt_stop(struct watchdog_device *wdog)
167 {
168 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
169
170 mutex_lock(&wdev->lock);
171 omap_wdt_disable(wdev);
172 pm_runtime_put_sync(wdev->dev);
173 wdev->omap_wdt_users = false;
174 mutex_unlock(&wdev->lock);
175 return 0;
176 }
177
omap_wdt_ping(struct watchdog_device * wdog)178 static int omap_wdt_ping(struct watchdog_device *wdog)
179 {
180 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
181
182 mutex_lock(&wdev->lock);
183 omap_wdt_reload(wdev);
184 mutex_unlock(&wdev->lock);
185
186 return 0;
187 }
188
omap_wdt_set_timeout(struct watchdog_device * wdog,unsigned int timeout)189 static int omap_wdt_set_timeout(struct watchdog_device *wdog,
190 unsigned int timeout)
191 {
192 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
193
194 mutex_lock(&wdev->lock);
195 omap_wdt_disable(wdev);
196 omap_wdt_set_timer(wdev, timeout);
197 omap_wdt_enable(wdev);
198 omap_wdt_reload(wdev);
199 wdog->timeout = timeout;
200 mutex_unlock(&wdev->lock);
201
202 return 0;
203 }
204
omap_wdt_get_timeleft(struct watchdog_device * wdog)205 static unsigned int omap_wdt_get_timeleft(struct watchdog_device *wdog)
206 {
207 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
208 void __iomem *base = wdev->base;
209 u32 value;
210
211 value = readl_relaxed(base + OMAP_WATCHDOG_CRR);
212 return GET_WCCR_SECS(value);
213 }
214
215 static const struct watchdog_info omap_wdt_info = {
216 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
217 .identity = "OMAP Watchdog",
218 };
219
220 static const struct watchdog_ops omap_wdt_ops = {
221 .owner = THIS_MODULE,
222 .start = omap_wdt_start,
223 .stop = omap_wdt_stop,
224 .ping = omap_wdt_ping,
225 .set_timeout = omap_wdt_set_timeout,
226 .get_timeleft = omap_wdt_get_timeleft,
227 };
228
omap_wdt_probe(struct platform_device * pdev)229 static int omap_wdt_probe(struct platform_device *pdev)
230 {
231 struct omap_wd_timer_platform_data *pdata = dev_get_platdata(&pdev->dev);
232 struct omap_wdt_dev *wdev;
233 int ret;
234
235 wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
236 if (!wdev)
237 return -ENOMEM;
238
239 wdev->omap_wdt_users = false;
240 wdev->dev = &pdev->dev;
241 wdev->wdt_trgr_pattern = 0x1234;
242 mutex_init(&wdev->lock);
243
244 /* reserve static register mappings */
245 wdev->base = devm_platform_ioremap_resource(pdev, 0);
246 if (IS_ERR(wdev->base))
247 return PTR_ERR(wdev->base);
248
249 wdev->wdog.info = &omap_wdt_info;
250 wdev->wdog.ops = &omap_wdt_ops;
251 wdev->wdog.min_timeout = TIMER_MARGIN_MIN;
252 wdev->wdog.max_timeout = TIMER_MARGIN_MAX;
253 wdev->wdog.timeout = TIMER_MARGIN_DEFAULT;
254 wdev->wdog.parent = &pdev->dev;
255
256 watchdog_init_timeout(&wdev->wdog, timer_margin, &pdev->dev);
257
258 watchdog_set_nowayout(&wdev->wdog, nowayout);
259
260 platform_set_drvdata(pdev, wdev);
261
262 pm_runtime_enable(wdev->dev);
263 pm_runtime_get_sync(wdev->dev);
264
265 if (pdata && pdata->read_reset_sources) {
266 u32 rs = pdata->read_reset_sources();
267 if (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT))
268 wdev->wdog.bootstatus = WDIOF_CARDRESET;
269 }
270
271 if (!early_enable)
272 omap_wdt_disable(wdev);
273
274 ret = watchdog_register_device(&wdev->wdog);
275 if (ret) {
276 pm_runtime_disable(wdev->dev);
277 return ret;
278 }
279
280 pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
281 readl_relaxed(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
282 wdev->wdog.timeout);
283
284 if (early_enable)
285 omap_wdt_start(&wdev->wdog);
286
287 pm_runtime_put(wdev->dev);
288
289 return 0;
290 }
291
omap_wdt_shutdown(struct platform_device * pdev)292 static void omap_wdt_shutdown(struct platform_device *pdev)
293 {
294 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
295
296 mutex_lock(&wdev->lock);
297 if (wdev->omap_wdt_users) {
298 omap_wdt_disable(wdev);
299 pm_runtime_put_sync(wdev->dev);
300 }
301 mutex_unlock(&wdev->lock);
302 }
303
omap_wdt_remove(struct platform_device * pdev)304 static int omap_wdt_remove(struct platform_device *pdev)
305 {
306 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
307
308 pm_runtime_disable(wdev->dev);
309 watchdog_unregister_device(&wdev->wdog);
310
311 return 0;
312 }
313
314 #ifdef CONFIG_PM
315
316 /* REVISIT ... not clear this is the best way to handle system suspend; and
317 * it's very inappropriate for selective device suspend (e.g. suspending this
318 * through sysfs rather than by stopping the watchdog daemon). Also, this
319 * may not play well enough with NOWAYOUT...
320 */
321
omap_wdt_suspend(struct platform_device * pdev,pm_message_t state)322 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
323 {
324 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
325
326 mutex_lock(&wdev->lock);
327 if (wdev->omap_wdt_users) {
328 omap_wdt_disable(wdev);
329 pm_runtime_put_sync(wdev->dev);
330 }
331 mutex_unlock(&wdev->lock);
332
333 return 0;
334 }
335
omap_wdt_resume(struct platform_device * pdev)336 static int omap_wdt_resume(struct platform_device *pdev)
337 {
338 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
339
340 mutex_lock(&wdev->lock);
341 if (wdev->omap_wdt_users) {
342 pm_runtime_get_sync(wdev->dev);
343 omap_wdt_enable(wdev);
344 omap_wdt_reload(wdev);
345 }
346 mutex_unlock(&wdev->lock);
347
348 return 0;
349 }
350
351 #else
352 #define omap_wdt_suspend NULL
353 #define omap_wdt_resume NULL
354 #endif
355
356 static const struct of_device_id omap_wdt_of_match[] = {
357 { .compatible = "ti,omap3-wdt", },
358 {},
359 };
360 MODULE_DEVICE_TABLE(of, omap_wdt_of_match);
361
362 static struct platform_driver omap_wdt_driver = {
363 .probe = omap_wdt_probe,
364 .remove = omap_wdt_remove,
365 .shutdown = omap_wdt_shutdown,
366 .suspend = omap_wdt_suspend,
367 .resume = omap_wdt_resume,
368 .driver = {
369 .name = "omap_wdt",
370 .of_match_table = omap_wdt_of_match,
371 },
372 };
373
374 module_platform_driver(omap_wdt_driver);
375
376 MODULE_AUTHOR("George G. Davis");
377 MODULE_LICENSE("GPL");
378 MODULE_ALIAS("platform:omap_wdt");
379
