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Linux/drivers/watchdog/rdc321x_wdt.c

  1 /*
  2  * RDC321x watchdog driver
  3  *
  4  * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
  5  *
  6  * This driver is highly inspired from the cpu5_wdt driver
  7  *
  8  * This program is free software; you can redistribute it and/or modify
  9  * it under the terms of the GNU General Public License as published by
 10  * the Free Software Foundation; either version 2 of the License, or
 11  * (at your option) any later version.
 12  *
 13  * This program is distributed in the hope that it will be useful,
 14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 16  * GNU General Public License for more details.
 17  *
 18  * You should have received a copy of the GNU General Public License
 19  * along with this program; if not, write to the Free Software
 20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 21  *
 22  */
 23 
 24 #include <linux/module.h>
 25 #include <linux/moduleparam.h>
 26 #include <linux/types.h>
 27 #include <linux/errno.h>
 28 #include <linux/miscdevice.h>
 29 #include <linux/fs.h>
 30 #include <linux/init.h>
 31 #include <linux/ioport.h>
 32 #include <linux/timer.h>
 33 #include <linux/completion.h>
 34 #include <linux/jiffies.h>
 35 #include <linux/platform_device.h>
 36 #include <linux/watchdog.h>
 37 #include <linux/io.h>
 38 #include <linux/uaccess.h>
 39 #include <linux/mfd/rdc321x.h>
 40 
 41 #define RDC_WDT_MASK    0x80000000 /* Mask */
 42 #define RDC_WDT_EN      0x00800000 /* Enable bit */
 43 #define RDC_WDT_WTI     0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
 44 #define RDC_WDT_RST     0x00100000 /* Reset bit */
 45 #define RDC_WDT_WIF     0x00040000 /* WDT IRQ Flag */
 46 #define RDC_WDT_IRT     0x00000100 /* IRQ Routing table */
 47 #define RDC_WDT_CNT     0x00000001 /* WDT count */
 48 
 49 #define RDC_CLS_TMR     0x80003844 /* Clear timer */
 50 
 51 #define RDC_WDT_INTERVAL        (HZ/10+1)
 52 
 53 static int ticks = 1000;
 54 
 55 /* some device data */
 56 
 57 static struct {
 58         struct completion stop;
 59         int running;
 60         struct timer_list timer;
 61         int queue;
 62         int default_ticks;
 63         unsigned long inuse;
 64         spinlock_t lock;
 65         struct pci_dev *sb_pdev;
 66         int base_reg;
 67 } rdc321x_wdt_device;
 68 
 69 /* generic helper functions */
 70 
 71 static void rdc321x_wdt_trigger(unsigned long unused)
 72 {
 73         unsigned long flags;
 74         u32 val;
 75 
 76         if (rdc321x_wdt_device.running)
 77                 ticks--;
 78 
 79         /* keep watchdog alive */
 80         spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
 81         pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
 82                                         rdc321x_wdt_device.base_reg, &val);
 83         val |= RDC_WDT_EN;
 84         pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 85                                         rdc321x_wdt_device.base_reg, val);
 86         spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
 87 
 88         /* requeue?? */
 89         if (rdc321x_wdt_device.queue && ticks)
 90                 mod_timer(&rdc321x_wdt_device.timer,
 91                                 jiffies + RDC_WDT_INTERVAL);
 92         else {
 93                 /* ticks doesn't matter anyway */
 94                 complete(&rdc321x_wdt_device.stop);
 95         }
 96 
 97 }
 98 
 99 static void rdc321x_wdt_reset(void)
100 {
101         ticks = rdc321x_wdt_device.default_ticks;
102 }
103 
104 static void rdc321x_wdt_start(void)
105 {
106         unsigned long flags;
107 
108         if (!rdc321x_wdt_device.queue) {
109                 rdc321x_wdt_device.queue = 1;
110 
111                 /* Clear the timer */
112                 spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
113                 pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
114                                 rdc321x_wdt_device.base_reg, RDC_CLS_TMR);
115 
116                 /* Enable watchdog and set the timeout to 81.92 us */
117                 pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
118                                         rdc321x_wdt_device.base_reg,
119                                         RDC_WDT_EN | RDC_WDT_CNT);
120                 spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
121 
122                 mod_timer(&rdc321x_wdt_device.timer,
123                                 jiffies + RDC_WDT_INTERVAL);
124         }
125 
126         /* if process dies, counter is not decremented */
127         rdc321x_wdt_device.running++;
128 }
129 
130 static int rdc321x_wdt_stop(void)
131 {
132         if (rdc321x_wdt_device.running)
133                 rdc321x_wdt_device.running = 0;
134 
135         ticks = rdc321x_wdt_device.default_ticks;
136 
137         return -EIO;
138 }
139 
140 /* filesystem operations */
141 static int rdc321x_wdt_open(struct inode *inode, struct file *file)
142 {
143         if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
144                 return -EBUSY;
145 
146         return nonseekable_open(inode, file);
147 }
148 
149 static int rdc321x_wdt_release(struct inode *inode, struct file *file)
150 {
151         clear_bit(0, &rdc321x_wdt_device.inuse);
152         return 0;
153 }
154 
155 static long rdc321x_wdt_ioctl(struct file *file, unsigned int cmd,
156                                 unsigned long arg)
157 {
158         void __user *argp = (void __user *)arg;
159         u32 value;
160         static const struct watchdog_info ident = {
161                 .options = WDIOF_CARDRESET,
162                 .identity = "RDC321x WDT",
163         };
164         unsigned long flags;
165 
166         switch (cmd) {
167         case WDIOC_KEEPALIVE:
168                 rdc321x_wdt_reset();
169                 break;
170         case WDIOC_GETSTATUS:
171                 /* Read the value from the DATA register */
172                 spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
173                 pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
174                                         rdc321x_wdt_device.base_reg, &value);
175                 spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
176                 if (copy_to_user(argp, &value, sizeof(u32)))
177                         return -EFAULT;
178                 break;
179         case WDIOC_GETSUPPORT:
180                 if (copy_to_user(argp, &ident, sizeof(ident)))
181                         return -EFAULT;
182                 break;
183         case WDIOC_SETOPTIONS:
184                 if (copy_from_user(&value, argp, sizeof(int)))
185                         return -EFAULT;
186                 switch (value) {
187                 case WDIOS_ENABLECARD:
188                         rdc321x_wdt_start();
189                         break;
190                 case WDIOS_DISABLECARD:
191                         return rdc321x_wdt_stop();
192                 default:
193                         return -EINVAL;
194                 }
195                 break;
196         default:
197                 return -ENOTTY;
198         }
199         return 0;
200 }
201 
202 static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
203                                 size_t count, loff_t *ppos)
204 {
205         if (!count)
206                 return -EIO;
207 
208         rdc321x_wdt_reset();
209 
210         return count;
211 }
212 
213 static const struct file_operations rdc321x_wdt_fops = {
214         .owner          = THIS_MODULE,
215         .llseek         = no_llseek,
216         .unlocked_ioctl = rdc321x_wdt_ioctl,
217         .open           = rdc321x_wdt_open,
218         .write          = rdc321x_wdt_write,
219         .release        = rdc321x_wdt_release,
220 };
221 
222 static struct miscdevice rdc321x_wdt_misc = {
223         .minor  = WATCHDOG_MINOR,
224         .name   = "watchdog",
225         .fops   = &rdc321x_wdt_fops,
226 };
227 
228 static int rdc321x_wdt_probe(struct platform_device *pdev)
229 {
230         int err;
231         struct resource *r;
232         struct rdc321x_wdt_pdata *pdata;
233 
234         pdata = dev_get_platdata(&pdev->dev);
235         if (!pdata) {
236                 dev_err(&pdev->dev, "no platform data supplied\n");
237                 return -ENODEV;
238         }
239 
240         r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");
241         if (!r) {
242                 dev_err(&pdev->dev, "failed to get wdt-reg resource\n");
243                 return -ENODEV;
244         }
245 
246         rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
247         rdc321x_wdt_device.base_reg = r->start;
248 
249         err = misc_register(&rdc321x_wdt_misc);
250         if (err < 0) {
251                 dev_err(&pdev->dev, "misc_register failed\n");
252                 return err;
253         }
254 
255         spin_lock_init(&rdc321x_wdt_device.lock);
256 
257         /* Reset the watchdog */
258         pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
259                                 rdc321x_wdt_device.base_reg, RDC_WDT_RST);
260 
261         init_completion(&rdc321x_wdt_device.stop);
262         rdc321x_wdt_device.queue = 0;
263 
264         clear_bit(0, &rdc321x_wdt_device.inuse);
265 
266         setup_timer(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
267 
268         rdc321x_wdt_device.default_ticks = ticks;
269 
270         dev_info(&pdev->dev, "watchdog init success\n");
271 
272         return 0;
273 }
274 
275 static int rdc321x_wdt_remove(struct platform_device *pdev)
276 {
277         if (rdc321x_wdt_device.queue) {
278                 rdc321x_wdt_device.queue = 0;
279                 wait_for_completion(&rdc321x_wdt_device.stop);
280         }
281 
282         misc_deregister(&rdc321x_wdt_misc);
283 
284         return 0;
285 }
286 
287 static struct platform_driver rdc321x_wdt_driver = {
288         .probe = rdc321x_wdt_probe,
289         .remove = rdc321x_wdt_remove,
290         .driver = {
291                 .owner = THIS_MODULE,
292                 .name = "rdc321x-wdt",
293         },
294 };
295 
296 module_platform_driver(rdc321x_wdt_driver);
297 
298 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
299 MODULE_DESCRIPTION("RDC321x watchdog driver");
300 MODULE_LICENSE("GPL");
301 

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