watchdog: Use pr_<fmt> and pr_<level>
[sfrench/cifs-2.6.git] / drivers / watchdog / pika_wdt.c
1 /*
2  * PIKA FPGA based Watchdog Timer
3  *
4  * Copyright (c) 2008 PIKA Technologies
5  *   Sean MacLennan <smaclennan@pikatech.com>
6  */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/init.h>
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/fs.h>
17 #include <linux/miscdevice.h>
18 #include <linux/watchdog.h>
19 #include <linux/reboot.h>
20 #include <linux/jiffies.h>
21 #include <linux/timer.h>
22 #include <linux/bitops.h>
23 #include <linux/uaccess.h>
24 #include <linux/io.h>
25 #include <linux/of_platform.h>
26
27 #define DRV_NAME "PIKA-WDT"
28
29 /* Hardware timeout in seconds */
30 #define WDT_HW_TIMEOUT 2
31
32 /* Timer heartbeat (500ms) */
33 #define WDT_TIMEOUT     (HZ/2)
34
35 /* User land timeout */
36 #define WDT_HEARTBEAT 15
37 static int heartbeat = WDT_HEARTBEAT;
38 module_param(heartbeat, int, 0);
39 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
40         "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
41
42 static int nowayout = WATCHDOG_NOWAYOUT;
43 module_param(nowayout, int, 0);
44 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
45         "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
46
47 static struct {
48         void __iomem *fpga;
49         unsigned long next_heartbeat;   /* the next_heartbeat for the timer */
50         unsigned long open;
51         char expect_close;
52         int bootstatus;
53         struct timer_list timer;        /* The timer that pings the watchdog */
54 } pikawdt_private;
55
56 static struct watchdog_info ident = {
57         .identity       = DRV_NAME,
58         .options        = WDIOF_CARDRESET |
59                           WDIOF_SETTIMEOUT |
60                           WDIOF_KEEPALIVEPING |
61                           WDIOF_MAGICCLOSE,
62 };
63
64 /*
65  * Reload the watchdog timer.  (ie, pat the watchdog)
66  */
67 static inline void pikawdt_reset(void)
68 {
69         /* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
70          * Bit 7,    WTCHDG_EN: When set to 1, the watchdog timer is enabled.
71          *           Once enabled, it cannot be disabled. The watchdog can be
72          *           kicked by performing any write access to the reset
73          *           control register (this register).
74          * Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
75          *           seconds. Valid ranges are 1 to 15 seconds. The value can
76          *           be modified dynamically.
77          */
78         unsigned reset = in_be32(pikawdt_private.fpga + 0x14);
79         /* enable with max timeout - 15 seconds */
80         reset |= (1 << 7) + (WDT_HW_TIMEOUT << 8);
81         out_be32(pikawdt_private.fpga + 0x14, reset);
82 }
83
84 /*
85  * Timer tick
86  */
87 static void pikawdt_ping(unsigned long data)
88 {
89         if (time_before(jiffies, pikawdt_private.next_heartbeat) ||
90                         (!nowayout && !pikawdt_private.open)) {
91                 pikawdt_reset();
92                 mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
93         } else
94                 pr_crit("I will reset your machine !\n");
95 }
96
97
98 static void pikawdt_keepalive(void)
99 {
100         pikawdt_private.next_heartbeat = jiffies + heartbeat * HZ;
101 }
102
103 static void pikawdt_start(void)
104 {
105         pikawdt_keepalive();
106         mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
107 }
108
109 /*
110  * Watchdog device is opened, and watchdog starts running.
111  */
112 static int pikawdt_open(struct inode *inode, struct file *file)
113 {
114         /* /dev/watchdog can only be opened once */
115         if (test_and_set_bit(0, &pikawdt_private.open))
116                 return -EBUSY;
117
118         pikawdt_start();
119
120         return nonseekable_open(inode, file);
121 }
122
123 /*
124  * Close the watchdog device.
125  */
126 static int pikawdt_release(struct inode *inode, struct file *file)
127 {
128         /* stop internal ping */
129         if (!pikawdt_private.expect_close)
130                 del_timer(&pikawdt_private.timer);
131
132         clear_bit(0, &pikawdt_private.open);
133         pikawdt_private.expect_close = 0;
134         return 0;
135 }
136
137 /*
138  * Pat the watchdog whenever device is written to.
139  */
140 static ssize_t pikawdt_write(struct file *file, const char __user *data,
141                              size_t len, loff_t *ppos)
142 {
143         if (!len)
144                 return 0;
145
146         /* Scan for magic character */
147         if (!nowayout) {
148                 size_t i;
149
150                 pikawdt_private.expect_close = 0;
151
152                 for (i = 0; i < len; i++) {
153                         char c;
154                         if (get_user(c, data + i))
155                                 return -EFAULT;
156                         if (c == 'V') {
157                                 pikawdt_private.expect_close = 42;
158                                 break;
159                         }
160                 }
161         }
162
163         pikawdt_keepalive();
164
165         return len;
166 }
167
168 /*
169  * Handle commands from user-space.
170  */
171 static long pikawdt_ioctl(struct file *file,
172                 unsigned int cmd, unsigned long arg)
173 {
174         void __user *argp = (void __user *)arg;
175         int __user *p = argp;
176         int new_value;
177
178         switch (cmd) {
179         case WDIOC_GETSUPPORT:
180                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
181
182         case WDIOC_GETSTATUS:
183                 return put_user(0, p);
184
185         case WDIOC_GETBOOTSTATUS:
186                 return put_user(pikawdt_private.bootstatus, p);
187
188         case WDIOC_KEEPALIVE:
189                 pikawdt_keepalive();
190                 return 0;
191
192         case WDIOC_SETTIMEOUT:
193                 if (get_user(new_value, p))
194                         return -EFAULT;
195
196                 heartbeat = new_value;
197                 pikawdt_keepalive();
198
199                 return put_user(new_value, p);  /* return current value */
200
201         case WDIOC_GETTIMEOUT:
202                 return put_user(heartbeat, p);
203         }
204         return -ENOTTY;
205 }
206
207
208 static const struct file_operations pikawdt_fops = {
209         .owner          = THIS_MODULE,
210         .llseek         = no_llseek,
211         .open           = pikawdt_open,
212         .release        = pikawdt_release,
213         .write          = pikawdt_write,
214         .unlocked_ioctl = pikawdt_ioctl,
215 };
216
217 static struct miscdevice pikawdt_miscdev = {
218         .minor  = WATCHDOG_MINOR,
219         .name   = "watchdog",
220         .fops   = &pikawdt_fops,
221 };
222
223 static int __init pikawdt_init(void)
224 {
225         struct device_node *np;
226         void __iomem *fpga;
227         static u32 post1;
228         int ret;
229
230         np = of_find_compatible_node(NULL, NULL, "pika,fpga");
231         if (np == NULL) {
232                 pr_err("Unable to find fpga\n");
233                 return -ENOENT;
234         }
235
236         pikawdt_private.fpga = of_iomap(np, 0);
237         of_node_put(np);
238         if (pikawdt_private.fpga == NULL) {
239                 pr_err("Unable to map fpga\n");
240                 return -ENOMEM;
241         }
242
243         ident.firmware_version = in_be32(pikawdt_private.fpga + 0x1c) & 0xffff;
244
245         /* POST information is in the sd area. */
246         np = of_find_compatible_node(NULL, NULL, "pika,fpga-sd");
247         if (np == NULL) {
248                 pr_err("Unable to find fpga-sd\n");
249                 ret = -ENOENT;
250                 goto out;
251         }
252
253         fpga = of_iomap(np, 0);
254         of_node_put(np);
255         if (fpga == NULL) {
256                 pr_err("Unable to map fpga-sd\n");
257                 ret = -ENOMEM;
258                 goto out;
259         }
260
261         /* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
262          * Bit 31,   WDOG: Set to 1 when the last reset was caused by a watchdog
263          *           timeout.
264          */
265         post1 = in_be32(fpga + 0x40);
266         if (post1 & 0x80000000)
267                 pikawdt_private.bootstatus = WDIOF_CARDRESET;
268
269         iounmap(fpga);
270
271         setup_timer(&pikawdt_private.timer, pikawdt_ping, 0);
272
273         ret = misc_register(&pikawdt_miscdev);
274         if (ret) {
275                 pr_err("Unable to register miscdev\n");
276                 goto out;
277         }
278
279         pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
280                 heartbeat, nowayout);
281         return 0;
282
283 out:
284         iounmap(pikawdt_private.fpga);
285         return ret;
286 }
287
288 static void __exit pikawdt_exit(void)
289 {
290         misc_deregister(&pikawdt_miscdev);
291
292         iounmap(pikawdt_private.fpga);
293 }
294
295 module_init(pikawdt_init);
296 module_exit(pikawdt_exit);
297
298 MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
299 MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
300 MODULE_LICENSE("GPL");
301 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
302