Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/drivers/watchdog/imx2_wdt.c

  1 /*
  2  * Watchdog driver for IMX2 and later processors
  3  *
  4  *  Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de>
  5  *  Copyright (C) 2014 Freescale Semiconductor, Inc.
  6  *
  7  * some parts adapted by similar drivers from Darius Augulis and Vladimir
  8  * Zapolskiy, additional improvements by Wim Van Sebroeck.
  9  *
 10  * This program is free software; you can redistribute it and/or modify it
 11  * under the terms of the GNU General Public License version 2 as published by
 12  * the Free Software Foundation.
 13  *
 14  * NOTE: MX1 has a slightly different Watchdog than MX2 and later:
 15  *
 16  *                      MX1:            MX2+:
 17  *                      ----            -----
 18  * Registers:           32-bit          16-bit
 19  * Stopable timer:      Yes             No
 20  * Need to enable clk:  No              Yes
 21  * Halt on suspend:     Manual          Can be automatic
 22  */
 23 
 24 #include <linux/clk.h>
 25 #include <linux/delay.h>
 26 #include <linux/init.h>
 27 #include <linux/io.h>
 28 #include <linux/jiffies.h>
 29 #include <linux/kernel.h>
 30 #include <linux/module.h>
 31 #include <linux/moduleparam.h>
 32 #include <linux/notifier.h>
 33 #include <linux/of_address.h>
 34 #include <linux/platform_device.h>
 35 #include <linux/reboot.h>
 36 #include <linux/regmap.h>
 37 #include <linux/timer.h>
 38 #include <linux/watchdog.h>
 39 
 40 #define DRIVER_NAME "imx2-wdt"
 41 
 42 #define IMX2_WDT_WCR            0x00            /* Control Register */
 43 #define IMX2_WDT_WCR_WT         (0xFF << 8)     /* -> Watchdog Timeout Field */
 44 #define IMX2_WDT_WCR_WRE        (1 << 3)        /* -> WDOG Reset Enable */
 45 #define IMX2_WDT_WCR_WDE        (1 << 2)        /* -> Watchdog Enable */
 46 #define IMX2_WDT_WCR_WDZST      (1 << 0)        /* -> Watchdog timer Suspend */
 47 
 48 #define IMX2_WDT_WSR            0x02            /* Service Register */
 49 #define IMX2_WDT_SEQ1           0x5555          /* -> service sequence 1 */
 50 #define IMX2_WDT_SEQ2           0xAAAA          /* -> service sequence 2 */
 51 
 52 #define IMX2_WDT_WRSR           0x04            /* Reset Status Register */
 53 #define IMX2_WDT_WRSR_TOUT      (1 << 1)        /* -> Reset due to Timeout */
 54 
 55 #define IMX2_WDT_MAX_TIME       128
 56 #define IMX2_WDT_DEFAULT_TIME   60              /* in seconds */
 57 
 58 #define WDOG_SEC_TO_COUNT(s)    ((s * 2 - 1) << 8)
 59 
 60 struct imx2_wdt_device {
 61         struct clk *clk;
 62         struct regmap *regmap;
 63         struct timer_list timer;        /* Pings the watchdog when closed */
 64         struct watchdog_device wdog;
 65         struct notifier_block restart_handler;
 66 };
 67 
 68 static bool nowayout = WATCHDOG_NOWAYOUT;
 69 module_param(nowayout, bool, 0);
 70 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 71                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 72 
 73 
 74 static unsigned timeout = IMX2_WDT_DEFAULT_TIME;
 75 module_param(timeout, uint, 0);
 76 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
 77                                 __MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")");
 78 
 79 static const struct watchdog_info imx2_wdt_info = {
 80         .identity = "imx2+ watchdog",
 81         .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 82 };
 83 
 84 static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
 85                                 void *cmd)
 86 {
 87         unsigned int wcr_enable = IMX2_WDT_WCR_WDE;
 88         struct imx2_wdt_device *wdev = container_of(this,
 89                                                     struct imx2_wdt_device,
 90                                                     restart_handler);
 91         /* Assert SRS signal */
 92         regmap_write(wdev->regmap, 0, wcr_enable);
 93         /*
 94          * Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be
 95          * written twice), we add another two writes to ensure there must be at
 96          * least two writes happen in the same one 32kHz clock period.  We save
 97          * the target check here, since the writes shouldn't be a huge burden
 98          * for other platforms.
 99          */
100         regmap_write(wdev->regmap, 0, wcr_enable);
101         regmap_write(wdev->regmap, 0, wcr_enable);
102 
103         /* wait for reset to assert... */
104         mdelay(500);
105 
106         return NOTIFY_DONE;
107 }
108 
109 static inline void imx2_wdt_setup(struct watchdog_device *wdog)
110 {
111         struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
112         u32 val;
113 
114         regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);
115 
116         /* Suspend timer in low power mode, write once-only */
117         val |= IMX2_WDT_WCR_WDZST;
118         /* Strip the old watchdog Time-Out value */
119         val &= ~IMX2_WDT_WCR_WT;
120         /* Generate reset if WDOG times out */
121         val &= ~IMX2_WDT_WCR_WRE;
122         /* Keep Watchdog Disabled */
123         val &= ~IMX2_WDT_WCR_WDE;
124         /* Set the watchdog's Time-Out value */
125         val |= WDOG_SEC_TO_COUNT(wdog->timeout);
126 
127         regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
128 
129         /* enable the watchdog */
130         val |= IMX2_WDT_WCR_WDE;
131         regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
132 }
133 
134 static inline bool imx2_wdt_is_running(struct imx2_wdt_device *wdev)
135 {
136         u32 val;
137 
138         regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);
139 
140         return val & IMX2_WDT_WCR_WDE;
141 }
142 
143 static int imx2_wdt_ping(struct watchdog_device *wdog)
144 {
145         struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
146 
147         regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1);
148         regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2);
149         return 0;
150 }
151 
152 static void imx2_wdt_timer_ping(unsigned long arg)
153 {
154         struct watchdog_device *wdog = (struct watchdog_device *)arg;
155         struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
156 
157         /* ping it every wdog->timeout / 2 seconds to prevent reboot */
158         imx2_wdt_ping(wdog);
159         mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
160 }
161 
162 static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
163                                 unsigned int new_timeout)
164 {
165         struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
166 
167         regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT,
168                            WDOG_SEC_TO_COUNT(new_timeout));
169         return 0;
170 }
171 
172 static int imx2_wdt_start(struct watchdog_device *wdog)
173 {
174         struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
175 
176         if (imx2_wdt_is_running(wdev)) {
177                 /* delete the timer that pings the watchdog after close */
178                 del_timer_sync(&wdev->timer);
179                 imx2_wdt_set_timeout(wdog, wdog->timeout);
180         } else
181                 imx2_wdt_setup(wdog);
182 
183         return imx2_wdt_ping(wdog);
184 }
185 
186 static int imx2_wdt_stop(struct watchdog_device *wdog)
187 {
188         /*
189          * We don't need a clk_disable, it cannot be disabled once started.
190          * We use a timer to ping the watchdog while /dev/watchdog is closed
191          */
192         imx2_wdt_timer_ping((unsigned long)wdog);
193         return 0;
194 }
195 
196 static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
197 {
198         struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
199 
200         if (imx2_wdt_is_running(wdev)) {
201                 imx2_wdt_set_timeout(wdog, wdog->timeout);
202                 imx2_wdt_timer_ping((unsigned long)wdog);
203         }
204 }
205 
206 static struct watchdog_ops imx2_wdt_ops = {
207         .owner = THIS_MODULE,
208         .start = imx2_wdt_start,
209         .stop = imx2_wdt_stop,
210         .ping = imx2_wdt_ping,
211         .set_timeout = imx2_wdt_set_timeout,
212 };
213 
214 static struct regmap_config imx2_wdt_regmap_config = {
215         .reg_bits = 16,
216         .reg_stride = 2,
217         .val_bits = 16,
218         .max_register = 0x8,
219 };
220 
221 static int __init imx2_wdt_probe(struct platform_device *pdev)
222 {
223         struct imx2_wdt_device *wdev;
224         struct watchdog_device *wdog;
225         struct resource *res;
226         void __iomem *base;
227         int ret;
228         u32 val;
229 
230         wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
231         if (!wdev)
232                 return -ENOMEM;
233 
234         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
235         base = devm_ioremap_resource(&pdev->dev, res);
236         if (IS_ERR(base))
237                 return PTR_ERR(base);
238 
239         wdev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
240                                                  &imx2_wdt_regmap_config);
241         if (IS_ERR(wdev->regmap)) {
242                 dev_err(&pdev->dev, "regmap init failed\n");
243                 return PTR_ERR(wdev->regmap);
244         }
245 
246         wdev->clk = devm_clk_get(&pdev->dev, NULL);
247         if (IS_ERR(wdev->clk)) {
248                 dev_err(&pdev->dev, "can't get Watchdog clock\n");
249                 return PTR_ERR(wdev->clk);
250         }
251 
252         wdog                    = &wdev->wdog;
253         wdog->info              = &imx2_wdt_info;
254         wdog->ops               = &imx2_wdt_ops;
255         wdog->min_timeout       = 1;
256         wdog->max_timeout       = IMX2_WDT_MAX_TIME;
257 
258         clk_prepare_enable(wdev->clk);
259 
260         regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val);
261         wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
262 
263         wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
264         if (wdog->timeout != timeout)
265                 dev_warn(&pdev->dev, "Initial timeout out of range! Clamped from %u to %u\n",
266                          timeout, wdog->timeout);
267 
268         platform_set_drvdata(pdev, wdog);
269         watchdog_set_drvdata(wdog, wdev);
270         watchdog_set_nowayout(wdog, nowayout);
271         watchdog_init_timeout(wdog, timeout, &pdev->dev);
272 
273         setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog);
274 
275         imx2_wdt_ping_if_active(wdog);
276 
277         ret = watchdog_register_device(wdog);
278         if (ret) {
279                 dev_err(&pdev->dev, "cannot register watchdog device\n");
280                 return ret;
281         }
282 
283         wdev->restart_handler.notifier_call = imx2_restart_handler;
284         wdev->restart_handler.priority = 128;
285         ret = register_restart_handler(&wdev->restart_handler);
286         if (ret)
287                 dev_err(&pdev->dev, "cannot register restart handler\n");
288 
289         dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n",
290                  wdog->timeout, nowayout);
291 
292         return 0;
293 }
294 
295 static int __exit imx2_wdt_remove(struct platform_device *pdev)
296 {
297         struct watchdog_device *wdog = platform_get_drvdata(pdev);
298         struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
299 
300         unregister_restart_handler(&wdev->restart_handler);
301 
302         watchdog_unregister_device(wdog);
303 
304         if (imx2_wdt_is_running(wdev)) {
305                 del_timer_sync(&wdev->timer);
306                 imx2_wdt_ping(wdog);
307                 dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
308         }
309         return 0;
310 }
311 
312 static void imx2_wdt_shutdown(struct platform_device *pdev)
313 {
314         struct watchdog_device *wdog = platform_get_drvdata(pdev);
315         struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
316 
317         if (imx2_wdt_is_running(wdev)) {
318                 /*
319                  * We are running, we need to delete the timer but will
320                  * give max timeout before reboot will take place
321                  */
322                 del_timer_sync(&wdev->timer);
323                 imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
324                 imx2_wdt_ping(wdog);
325                 dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n");
326         }
327 }
328 
329 static const struct of_device_id imx2_wdt_dt_ids[] = {
330         { .compatible = "fsl,imx21-wdt", },
331         { /* sentinel */ }
332 };
333 MODULE_DEVICE_TABLE(of, imx2_wdt_dt_ids);
334 
335 static struct platform_driver imx2_wdt_driver = {
336         .remove         = __exit_p(imx2_wdt_remove),
337         .shutdown       = imx2_wdt_shutdown,
338         .driver         = {
339                 .name   = DRIVER_NAME,
340                 .owner  = THIS_MODULE,
341                 .of_match_table = imx2_wdt_dt_ids,
342         },
343 };
344 
345 module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe);
346 
347 MODULE_AUTHOR("Wolfram Sang");
348 MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
349 MODULE_LICENSE("GPL v2");
350 MODULE_ALIAS("platform:" DRIVER_NAME);
351 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us