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

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