video: tegra: dc: Add quick for Vizio P series
[linux-3.10.git] / drivers / watchdog / iop_wdt.c
1 /*
2  * drivers/char/watchdog/iop_wdt.c
3  *
4  * WDT driver for Intel I/O Processors
5  * Copyright (C) 2005, Intel Corporation.
6  *
7  * Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc.
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms and conditions of the GNU General Public License,
11  * version 2, as published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope it will be useful, but WITHOUT
14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
16  * more details.
17  *
18  * You should have received a copy of the GNU General Public License along with
19  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
20  * Place - Suite 330, Boston, MA 02111-1307 USA.
21  *
22  *      Curt E Bruns <curt.e.bruns@intel.com>
23  *      Peter Milne <peter.milne@d-tacq.com>
24  *      Dan Williams <dan.j.williams@intel.com>
25  */
26
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
29 #include <linux/module.h>
30 #include <linux/kernel.h>
31 #include <linux/fs.h>
32 #include <linux/init.h>
33 #include <linux/device.h>
34 #include <linux/miscdevice.h>
35 #include <linux/watchdog.h>
36 #include <linux/uaccess.h>
37 #include <mach/hardware.h>
38
39 static bool nowayout = WATCHDOG_NOWAYOUT;
40 static unsigned long wdt_status;
41 static unsigned long boot_status;
42 static DEFINE_SPINLOCK(wdt_lock);
43
44 #define WDT_IN_USE              0
45 #define WDT_OK_TO_CLOSE         1
46 #define WDT_ENABLED             2
47
48 static unsigned long iop_watchdog_timeout(void)
49 {
50         return (0xffffffffUL / get_iop_tick_rate());
51 }
52
53 /**
54  * wdt_supports_disable - determine if we are accessing a iop13xx watchdog
55  * or iop3xx by whether it has a disable command
56  */
57 static int wdt_supports_disable(void)
58 {
59         int can_disable;
60
61         if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM)
62                 can_disable = 1;
63         else
64                 can_disable = 0;
65
66         return can_disable;
67 }
68
69 static void wdt_enable(void)
70 {
71         /* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF
72          * Takes approx. 10.7s to timeout
73          */
74         spin_lock(&wdt_lock);
75         write_wdtcr(IOP_WDTCR_EN_ARM);
76         write_wdtcr(IOP_WDTCR_EN);
77         spin_unlock(&wdt_lock);
78 }
79
80 /* returns 0 if the timer was successfully disabled */
81 static int wdt_disable(void)
82 {
83         /* Stop Counting */
84         if (wdt_supports_disable()) {
85                 spin_lock(&wdt_lock);
86                 write_wdtcr(IOP_WDTCR_DIS_ARM);
87                 write_wdtcr(IOP_WDTCR_DIS);
88                 clear_bit(WDT_ENABLED, &wdt_status);
89                 spin_unlock(&wdt_lock);
90                 pr_info("Disabled\n");
91                 return 0;
92         } else
93                 return 1;
94 }
95
96 static int iop_wdt_open(struct inode *inode, struct file *file)
97 {
98         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
99                 return -EBUSY;
100
101         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
102         wdt_enable();
103         set_bit(WDT_ENABLED, &wdt_status);
104         return nonseekable_open(inode, file);
105 }
106
107 static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len,
108                   loff_t *ppos)
109 {
110         if (len) {
111                 if (!nowayout) {
112                         size_t i;
113
114                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
115
116                         for (i = 0; i != len; i++) {
117                                 char c;
118
119                                 if (get_user(c, data + i))
120                                         return -EFAULT;
121                                 if (c == 'V')
122                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
123                         }
124                 }
125                 wdt_enable();
126         }
127         return len;
128 }
129
130 static const struct watchdog_info ident = {
131         .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
132         .identity = "iop watchdog",
133 };
134
135 static long iop_wdt_ioctl(struct file *file,
136                                 unsigned int cmd, unsigned long arg)
137 {
138         int options;
139         int ret = -ENOTTY;
140         int __user *argp = (int __user *)arg;
141
142         switch (cmd) {
143         case WDIOC_GETSUPPORT:
144                 if (copy_to_user(argp, &ident, sizeof(ident)))
145                         ret = -EFAULT;
146                 else
147                         ret = 0;
148                 break;
149
150         case WDIOC_GETSTATUS:
151                 ret = put_user(0, argp);
152                 break;
153
154         case WDIOC_GETBOOTSTATUS:
155                 ret = put_user(boot_status, argp);
156                 break;
157
158         case WDIOC_SETOPTIONS:
159                 if (get_user(options, (int *)arg))
160                         return -EFAULT;
161
162                 if (options & WDIOS_DISABLECARD) {
163                         if (!nowayout) {
164                                 if (wdt_disable() == 0) {
165                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
166                                         ret = 0;
167                                 } else
168                                         ret = -ENXIO;
169                         } else
170                                 ret = 0;
171                 }
172                 if (options & WDIOS_ENABLECARD) {
173                         wdt_enable();
174                         ret = 0;
175                 }
176                 break;
177
178         case WDIOC_KEEPALIVE:
179                 wdt_enable();
180                 ret = 0;
181                 break;
182
183         case WDIOC_GETTIMEOUT:
184                 ret = put_user(iop_watchdog_timeout(), argp);
185                 break;
186         }
187         return ret;
188 }
189
190 static int iop_wdt_release(struct inode *inode, struct file *file)
191 {
192         int state = 1;
193         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
194                 if (test_bit(WDT_ENABLED, &wdt_status))
195                         state = wdt_disable();
196
197         /* if the timer is not disabled reload and notify that we are still
198          * going down
199          */
200         if (state != 0) {
201                 wdt_enable();
202                 pr_crit("Device closed unexpectedly - reset in %lu seconds\n",
203                         iop_watchdog_timeout());
204         }
205
206         clear_bit(WDT_IN_USE, &wdt_status);
207         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
208
209         return 0;
210 }
211
212 static const struct file_operations iop_wdt_fops = {
213         .owner = THIS_MODULE,
214         .llseek = no_llseek,
215         .write = iop_wdt_write,
216         .unlocked_ioctl = iop_wdt_ioctl,
217         .open = iop_wdt_open,
218         .release = iop_wdt_release,
219 };
220
221 static struct miscdevice iop_wdt_miscdev = {
222         .minor = WATCHDOG_MINOR,
223         .name = "watchdog",
224         .fops = &iop_wdt_fops,
225 };
226
227 static int __init iop_wdt_init(void)
228 {
229         int ret;
230
231         /* check if the reset was caused by the watchdog timer */
232         boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0;
233
234         /* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset
235          * NOTE: An IB Reset will Reset both cores in the IOP342
236          */
237         write_wdtsr(IOP13XX_WDTCR_IB_RESET);
238
239         /* Register after we have the device set up so we cannot race
240            with an open */
241         ret = misc_register(&iop_wdt_miscdev);
242         if (ret == 0)
243                 pr_info("timeout %lu sec\n", iop_watchdog_timeout());
244
245         return ret;
246 }
247
248 static void __exit iop_wdt_exit(void)
249 {
250         misc_deregister(&iop_wdt_miscdev);
251 }
252
253 module_init(iop_wdt_init);
254 module_exit(iop_wdt_exit);
255
256 module_param(nowayout, bool, 0);
257 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
258
259 MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
260 MODULE_DESCRIPTION("iop watchdog timer driver");
261 MODULE_LICENSE("GPL");
262 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);