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Linux/drivers/watchdog/omap_wdt.c

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

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