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Linux/drivers/watchdog/bcm63xx_wdt.c

  1 /*
  2  *  Broadcom BCM63xx SoC watchdog driver
  3  *
  4  *  Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
  5  *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
  6  *
  7  *  This program is free software; you can redistribute it and/or
  8  *  modify it under the terms of the GNU General Public License
  9  *  as published by the Free Software Foundation; either version
 10  *  2 of the License, or (at your option) any later version.
 11  */
 12 
 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 14 
 15 #include <linux/bitops.h>
 16 #include <linux/errno.h>
 17 #include <linux/fs.h>
 18 #include <linux/init.h>
 19 #include <linux/io.h>
 20 #include <linux/kernel.h>
 21 #include <linux/miscdevice.h>
 22 #include <linux/module.h>
 23 #include <linux/moduleparam.h>
 24 #include <linux/types.h>
 25 #include <linux/uaccess.h>
 26 #include <linux/watchdog.h>
 27 #include <linux/timer.h>
 28 #include <linux/jiffies.h>
 29 #include <linux/interrupt.h>
 30 #include <linux/ptrace.h>
 31 #include <linux/resource.h>
 32 #include <linux/platform_device.h>
 33 
 34 #include <bcm63xx_cpu.h>
 35 #include <bcm63xx_io.h>
 36 #include <bcm63xx_regs.h>
 37 #include <bcm63xx_timer.h>
 38 
 39 #define PFX KBUILD_MODNAME
 40 
 41 #define WDT_HZ          50000000 /* Fclk */
 42 #define WDT_DEFAULT_TIME        30      /* seconds */
 43 #define WDT_MAX_TIME            256     /* seconds */
 44 
 45 static struct {
 46         void __iomem *regs;
 47         struct timer_list timer;
 48         int default_ticks;
 49         unsigned long inuse;
 50         atomic_t ticks;
 51 } bcm63xx_wdt_device;
 52 
 53 static int expect_close;
 54 
 55 static int wdt_time = WDT_DEFAULT_TIME;
 56 static bool nowayout = WATCHDOG_NOWAYOUT;
 57 module_param(nowayout, bool, 0);
 58 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 59         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 60 
 61 /* HW functions */
 62 static void bcm63xx_wdt_hw_start(void)
 63 {
 64         bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
 65         bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
 66         bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
 67 }
 68 
 69 static void bcm63xx_wdt_hw_stop(void)
 70 {
 71         bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
 72         bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
 73 }
 74 
 75 static void bcm63xx_wdt_isr(void *data)
 76 {
 77         struct pt_regs *regs = get_irq_regs();
 78 
 79         die(PFX " fire", regs);
 80 }
 81 
 82 static void bcm63xx_timer_tick(unsigned long unused)
 83 {
 84         if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
 85                 bcm63xx_wdt_hw_start();
 86                 mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
 87         } else
 88                 pr_crit("watchdog will restart system\n");
 89 }
 90 
 91 static void bcm63xx_wdt_pet(void)
 92 {
 93         atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
 94 }
 95 
 96 static void bcm63xx_wdt_start(void)
 97 {
 98         bcm63xx_wdt_pet();
 99         bcm63xx_timer_tick(0);
100 }
101 
102 static void bcm63xx_wdt_pause(void)
103 {
104         del_timer_sync(&bcm63xx_wdt_device.timer);
105         bcm63xx_wdt_hw_stop();
106 }
107 
108 static int bcm63xx_wdt_settimeout(int new_time)
109 {
110         if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
111                 return -EINVAL;
112 
113         wdt_time = new_time;
114 
115         return 0;
116 }
117 
118 static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
119 {
120         if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
121                 return -EBUSY;
122 
123         bcm63xx_wdt_start();
124         return nonseekable_open(inode, file);
125 }
126 
127 static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
128 {
129         if (expect_close == 42)
130                 bcm63xx_wdt_pause();
131         else {
132                 pr_crit("Unexpected close, not stopping watchdog!\n");
133                 bcm63xx_wdt_start();
134         }
135         clear_bit(0, &bcm63xx_wdt_device.inuse);
136         expect_close = 0;
137         return 0;
138 }
139 
140 static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
141                                 size_t len, loff_t *ppos)
142 {
143         if (len) {
144                 if (!nowayout) {
145                         size_t i;
146 
147                         /* In case it was set long ago */
148                         expect_close = 0;
149 
150                         for (i = 0; i != len; i++) {
151                                 char c;
152                                 if (get_user(c, data + i))
153                                         return -EFAULT;
154                                 if (c == 'V')
155                                         expect_close = 42;
156                         }
157                 }
158                 bcm63xx_wdt_pet();
159         }
160         return len;
161 }
162 
163 static struct watchdog_info bcm63xx_wdt_info = {
164         .identity       = PFX,
165         .options        = WDIOF_SETTIMEOUT |
166                                 WDIOF_KEEPALIVEPING |
167                                 WDIOF_MAGICCLOSE,
168 };
169 
170 
171 static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
172                                 unsigned long arg)
173 {
174         void __user *argp = (void __user *)arg;
175         int __user *p = argp;
176         int new_value, retval = -EINVAL;
177 
178         switch (cmd) {
179         case WDIOC_GETSUPPORT:
180                 return copy_to_user(argp, &bcm63xx_wdt_info,
181                         sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
182 
183         case WDIOC_GETSTATUS:
184         case WDIOC_GETBOOTSTATUS:
185                 return put_user(0, p);
186 
187         case WDIOC_SETOPTIONS:
188                 if (get_user(new_value, p))
189                         return -EFAULT;
190 
191                 if (new_value & WDIOS_DISABLECARD) {
192                         bcm63xx_wdt_pause();
193                         retval = 0;
194                 }
195                 if (new_value & WDIOS_ENABLECARD) {
196                         bcm63xx_wdt_start();
197                         retval = 0;
198                 }
199 
200                 return retval;
201 
202         case WDIOC_KEEPALIVE:
203                 bcm63xx_wdt_pet();
204                 return 0;
205 
206         case WDIOC_SETTIMEOUT:
207                 if (get_user(new_value, p))
208                         return -EFAULT;
209 
210                 if (bcm63xx_wdt_settimeout(new_value))
211                         return -EINVAL;
212 
213                 bcm63xx_wdt_pet();
214 
215         case WDIOC_GETTIMEOUT:
216                 return put_user(wdt_time, p);
217 
218         default:
219                 return -ENOTTY;
220 
221         }
222 }
223 
224 static const struct file_operations bcm63xx_wdt_fops = {
225         .owner          = THIS_MODULE,
226         .llseek         = no_llseek,
227         .write          = bcm63xx_wdt_write,
228         .unlocked_ioctl = bcm63xx_wdt_ioctl,
229         .open           = bcm63xx_wdt_open,
230         .release        = bcm63xx_wdt_release,
231 };
232 
233 static struct miscdevice bcm63xx_wdt_miscdev = {
234         .minor  = WATCHDOG_MINOR,
235         .name   = "watchdog",
236         .fops   = &bcm63xx_wdt_fops,
237 };
238 
239 
240 static int bcm63xx_wdt_probe(struct platform_device *pdev)
241 {
242         int ret;
243         struct resource *r;
244 
245         setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
246 
247         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
248         if (!r) {
249                 dev_err(&pdev->dev, "failed to get resources\n");
250                 return -ENODEV;
251         }
252 
253         bcm63xx_wdt_device.regs = devm_ioremap_nocache(&pdev->dev, r->start,
254                                                         resource_size(r));
255         if (!bcm63xx_wdt_device.regs) {
256                 dev_err(&pdev->dev, "failed to remap I/O resources\n");
257                 return -ENXIO;
258         }
259 
260         ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
261         if (ret < 0) {
262                 dev_err(&pdev->dev, "failed to register wdt timer isr\n");
263                 return ret;
264         }
265 
266         if (bcm63xx_wdt_settimeout(wdt_time)) {
267                 bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
268                 dev_info(&pdev->dev,
269                         ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
270                         wdt_time);
271         }
272 
273         ret = misc_register(&bcm63xx_wdt_miscdev);
274         if (ret < 0) {
275                 dev_err(&pdev->dev, "failed to register watchdog device\n");
276                 goto unregister_timer;
277         }
278 
279         dev_info(&pdev->dev, " started, timer margin: %d sec\n",
280                                                 WDT_DEFAULT_TIME);
281 
282         return 0;
283 
284 unregister_timer:
285         bcm63xx_timer_unregister(TIMER_WDT_ID);
286         return ret;
287 }
288 
289 static int bcm63xx_wdt_remove(struct platform_device *pdev)
290 {
291         if (!nowayout)
292                 bcm63xx_wdt_pause();
293 
294         misc_deregister(&bcm63xx_wdt_miscdev);
295         bcm63xx_timer_unregister(TIMER_WDT_ID);
296         return 0;
297 }
298 
299 static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
300 {
301         bcm63xx_wdt_pause();
302 }
303 
304 static struct platform_driver bcm63xx_wdt_driver = {
305         .probe  = bcm63xx_wdt_probe,
306         .remove = bcm63xx_wdt_remove,
307         .shutdown = bcm63xx_wdt_shutdown,
308         .driver = {
309                 .owner = THIS_MODULE,
310                 .name = "bcm63xx-wdt",
311         }
312 };
313 
314 module_platform_driver(bcm63xx_wdt_driver);
315 
316 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
317 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
318 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
319 MODULE_LICENSE("GPL");
320 MODULE_ALIAS("platform:bcm63xx-wdt");
321 

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