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

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