Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 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

Linux/drivers/watchdog/ath79_wdt.c

  1 /*
  2  * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
  3  *
  4  * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
  5  * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
  6  *
  7  * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
  8  *      Author: Deepak Saxena <dsaxena@plexity.net>
  9  *      Copyright 2004 (c) MontaVista, Software, Inc.
 10  *
 11  * which again was based on sa1100 driver,
 12  *      Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
 13  *
 14  * This program is free software; you can redistribute it and/or modify it
 15  * under the terms of the GNU General Public License version 2 as published
 16  * by the Free Software Foundation.
 17  *
 18  */
 19 
 20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 21 
 22 #include <linux/bitops.h>
 23 #include <linux/errno.h>
 24 #include <linux/fs.h>
 25 #include <linux/init.h>
 26 #include <linux/io.h>
 27 #include <linux/kernel.h>
 28 #include <linux/miscdevice.h>
 29 #include <linux/module.h>
 30 #include <linux/moduleparam.h>
 31 #include <linux/platform_device.h>
 32 #include <linux/types.h>
 33 #include <linux/watchdog.h>
 34 #include <linux/clk.h>
 35 #include <linux/err.h>
 36 #include <linux/of.h>
 37 #include <linux/of_platform.h>
 38 
 39 #define DRIVER_NAME     "ath79-wdt"
 40 
 41 #define WDT_TIMEOUT     15      /* seconds */
 42 
 43 #define WDOG_REG_CTRL           0x00
 44 #define WDOG_REG_TIMER          0x04
 45 
 46 #define WDOG_CTRL_LAST_RESET    BIT(31)
 47 #define WDOG_CTRL_ACTION_MASK   3
 48 #define WDOG_CTRL_ACTION_NONE   0       /* no action */
 49 #define WDOG_CTRL_ACTION_GPI    1       /* general purpose interrupt */
 50 #define WDOG_CTRL_ACTION_NMI    2       /* NMI */
 51 #define WDOG_CTRL_ACTION_FCR    3       /* full chip reset */
 52 
 53 static bool nowayout = WATCHDOG_NOWAYOUT;
 54 module_param(nowayout, bool, 0);
 55 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 56                            "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 57 
 58 static int timeout = WDT_TIMEOUT;
 59 module_param(timeout, int, 0);
 60 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
 61                           "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");
 62 
 63 static unsigned long wdt_flags;
 64 
 65 #define WDT_FLAGS_BUSY          0
 66 #define WDT_FLAGS_EXPECT_CLOSE  1
 67 
 68 static struct clk *wdt_clk;
 69 static unsigned long wdt_freq;
 70 static int boot_status;
 71 static int max_timeout;
 72 static void __iomem *wdt_base;
 73 
 74 static inline void ath79_wdt_wr(unsigned reg, u32 val)
 75 {
 76         iowrite32(val, wdt_base + reg);
 77 }
 78 
 79 static inline u32 ath79_wdt_rr(unsigned reg)
 80 {
 81         return ioread32(wdt_base + reg);
 82 }
 83 
 84 static inline void ath79_wdt_keepalive(void)
 85 {
 86         ath79_wdt_wr(WDOG_REG_TIMER, wdt_freq * timeout);
 87         /* flush write */
 88         ath79_wdt_rr(WDOG_REG_TIMER);
 89 }
 90 
 91 static inline void ath79_wdt_enable(void)
 92 {
 93         ath79_wdt_keepalive();
 94         ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_FCR);
 95         /* flush write */
 96         ath79_wdt_rr(WDOG_REG_CTRL);
 97 }
 98 
 99 static inline void ath79_wdt_disable(void)
100 {
101         ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_NONE);
102         /* flush write */
103         ath79_wdt_rr(WDOG_REG_CTRL);
104 }
105 
106 static int ath79_wdt_set_timeout(int val)
107 {
108         if (val < 1 || val > max_timeout)
109                 return -EINVAL;
110 
111         timeout = val;
112         ath79_wdt_keepalive();
113 
114         return 0;
115 }
116 
117 static int ath79_wdt_open(struct inode *inode, struct file *file)
118 {
119         if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
120                 return -EBUSY;
121 
122         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
123         ath79_wdt_enable();
124 
125         return nonseekable_open(inode, file);
126 }
127 
128 static int ath79_wdt_release(struct inode *inode, struct file *file)
129 {
130         if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
131                 ath79_wdt_disable();
132         else {
133                 pr_crit("device closed unexpectedly, watchdog timer will not stop!\n");
134                 ath79_wdt_keepalive();
135         }
136 
137         clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
138         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
139 
140         return 0;
141 }
142 
143 static ssize_t ath79_wdt_write(struct file *file, const char *data,
144                                 size_t len, loff_t *ppos)
145 {
146         if (len) {
147                 if (!nowayout) {
148                         size_t i;
149 
150                         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
151 
152                         for (i = 0; i != len; i++) {
153                                 char c;
154 
155                                 if (get_user(c, data + i))
156                                         return -EFAULT;
157 
158                                 if (c == 'V')
159                                         set_bit(WDT_FLAGS_EXPECT_CLOSE,
160                                                 &wdt_flags);
161                         }
162                 }
163 
164                 ath79_wdt_keepalive();
165         }
166 
167         return len;
168 }
169 
170 static const struct watchdog_info ath79_wdt_info = {
171         .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
172                                   WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
173         .firmware_version       = 0,
174         .identity               = "ATH79 watchdog",
175 };
176 
177 static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
178                             unsigned long arg)
179 {
180         void __user *argp = (void __user *)arg;
181         int __user *p = argp;
182         int err;
183         int t;
184 
185         switch (cmd) {
186         case WDIOC_GETSUPPORT:
187                 err = copy_to_user(argp, &ath79_wdt_info,
188                                    sizeof(ath79_wdt_info)) ? -EFAULT : 0;
189                 break;
190 
191         case WDIOC_GETSTATUS:
192                 err = put_user(0, p);
193                 break;
194 
195         case WDIOC_GETBOOTSTATUS:
196                 err = put_user(boot_status, p);
197                 break;
198 
199         case WDIOC_KEEPALIVE:
200                 ath79_wdt_keepalive();
201                 err = 0;
202                 break;
203 
204         case WDIOC_SETTIMEOUT:
205                 err = get_user(t, p);
206                 if (err)
207                         break;
208 
209                 err = ath79_wdt_set_timeout(t);
210                 if (err)
211                         break;
212 
213                 /* fallthrough */
214         case WDIOC_GETTIMEOUT:
215                 err = put_user(timeout, p);
216                 break;
217 
218         default:
219                 err = -ENOTTY;
220                 break;
221         }
222 
223         return err;
224 }
225 
226 static const struct file_operations ath79_wdt_fops = {
227         .owner          = THIS_MODULE,
228         .llseek         = no_llseek,
229         .write          = ath79_wdt_write,
230         .unlocked_ioctl = ath79_wdt_ioctl,
231         .open           = ath79_wdt_open,
232         .release        = ath79_wdt_release,
233 };
234 
235 static struct miscdevice ath79_wdt_miscdev = {
236         .minor = WATCHDOG_MINOR,
237         .name = "watchdog",
238         .fops = &ath79_wdt_fops,
239 };
240 
241 static int ath79_wdt_probe(struct platform_device *pdev)
242 {
243         struct resource *res;
244         u32 ctrl;
245         int err;
246 
247         if (wdt_base)
248                 return -EBUSY;
249 
250         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
251         wdt_base = devm_ioremap_resource(&pdev->dev, res);
252         if (IS_ERR(wdt_base))
253                 return PTR_ERR(wdt_base);
254 
255         wdt_clk = devm_clk_get(&pdev->dev, "wdt");
256         if (IS_ERR(wdt_clk))
257                 return PTR_ERR(wdt_clk);
258 
259         err = clk_enable(wdt_clk);
260         if (err)
261                 return err;
262 
263         wdt_freq = clk_get_rate(wdt_clk);
264         if (!wdt_freq) {
265                 err = -EINVAL;
266                 goto err_clk_disable;
267         }
268 
269         max_timeout = (0xfffffffful / wdt_freq);
270         if (timeout < 1 || timeout > max_timeout) {
271                 timeout = max_timeout;
272                 dev_info(&pdev->dev,
273                         "timeout value must be 0 < timeout < %d, using %d\n",
274                         max_timeout, timeout);
275         }
276 
277         ctrl = ath79_wdt_rr(WDOG_REG_CTRL);
278         boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
279 
280         err = misc_register(&ath79_wdt_miscdev);
281         if (err) {
282                 dev_err(&pdev->dev,
283                         "unable to register misc device, err=%d\n", err);
284                 goto err_clk_disable;
285         }
286 
287         return 0;
288 
289 err_clk_disable:
290         clk_disable(wdt_clk);
291         return err;
292 }
293 
294 static int ath79_wdt_remove(struct platform_device *pdev)
295 {
296         misc_deregister(&ath79_wdt_miscdev);
297         clk_disable(wdt_clk);
298         return 0;
299 }
300 
301 static void ath97_wdt_shutdown(struct platform_device *pdev)
302 {
303         ath79_wdt_disable();
304 }
305 
306 #ifdef CONFIG_OF
307 static const struct of_device_id ath79_wdt_match[] = {
308         { .compatible = "qca,ar7130-wdt" },
309         {},
310 };
311 MODULE_DEVICE_TABLE(of, ath79_wdt_match);
312 #endif
313 
314 static struct platform_driver ath79_wdt_driver = {
315         .probe          = ath79_wdt_probe,
316         .remove         = ath79_wdt_remove,
317         .shutdown       = ath97_wdt_shutdown,
318         .driver         = {
319                 .name   = DRIVER_NAME,
320                 .owner  = THIS_MODULE,
321                 .of_match_table = of_match_ptr(ath79_wdt_match),
322         },
323 };
324 
325 module_platform_driver(ath79_wdt_driver);
326 
327 MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
328 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
329 MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
330 MODULE_LICENSE("GPL v2");
331 MODULE_ALIAS("platform:" DRIVER_NAME);
332 

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