Merge branches 'core/debug', 'core/futexes', 'core/locking', 'core/rcu', 'core/signal...
[linux-2.6] / drivers / watchdog / pnx4008_wdt.c
1 /*
2  * drivers/char/watchdog/pnx4008_wdt.c
3  *
4  * Watchdog driver for PNX4008 board
5  *
6  * Authors: Dmitry Chigirev <source@mvista.com>,
7  *          Vitaly Wool <vitalywool@gmail.com>
8  * Based on sa1100 driver,
9  * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
10  *
11  * 2005-2006 (c) MontaVista Software, Inc. This file is licensed under
12  * the terms of the GNU General Public License version 2. This program
13  * is licensed "as is" without any warranty of any kind, whether express
14  * or implied.
15  */
16
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/types.h>
20 #include <linux/kernel.h>
21 #include <linux/fs.h>
22 #include <linux/miscdevice.h>
23 #include <linux/watchdog.h>
24 #include <linux/init.h>
25 #include <linux/bitops.h>
26 #include <linux/ioport.h>
27 #include <linux/device.h>
28 #include <linux/platform_device.h>
29 #include <linux/clk.h>
30 #include <linux/spinlock.h>
31 #include <linux/uaccess.h>
32 #include <linux/io.h>
33 #include <mach/hardware.h>
34
35 #define MODULE_NAME "PNX4008-WDT: "
36
37 /* WatchDog Timer - Chapter 23 Page 207 */
38
39 #define DEFAULT_HEARTBEAT 19
40 #define MAX_HEARTBEAT     60
41
42 /* Watchdog timer register set definition */
43 #define WDTIM_INT(p)     ((p) + 0x0)
44 #define WDTIM_CTRL(p)    ((p) + 0x4)
45 #define WDTIM_COUNTER(p) ((p) + 0x8)
46 #define WDTIM_MCTRL(p)   ((p) + 0xC)
47 #define WDTIM_MATCH0(p)  ((p) + 0x10)
48 #define WDTIM_EMR(p)     ((p) + 0x14)
49 #define WDTIM_PULSE(p)   ((p) + 0x18)
50 #define WDTIM_RES(p)     ((p) + 0x1C)
51
52 /* WDTIM_INT bit definitions */
53 #define MATCH_INT      1
54
55 /* WDTIM_CTRL bit definitions */
56 #define COUNT_ENAB     1
57 #define RESET_COUNT    (1<<1)
58 #define DEBUG_EN       (1<<2)
59
60 /* WDTIM_MCTRL bit definitions */
61 #define MR0_INT        1
62 #undef  RESET_COUNT0
63 #define RESET_COUNT0   (1<<2)
64 #define STOP_COUNT0    (1<<2)
65 #define M_RES1         (1<<3)
66 #define M_RES2         (1<<4)
67 #define RESFRC1        (1<<5)
68 #define RESFRC2        (1<<6)
69
70 /* WDTIM_EMR bit definitions */
71 #define EXT_MATCH0      1
72 #define MATCH_OUTPUT_HIGH (2<<4)        /*a MATCH_CTRL setting */
73
74 /* WDTIM_RES bit definitions */
75 #define WDOG_RESET      1       /* read only */
76
77 #define WDOG_COUNTER_RATE 13000000      /*the counter clock is 13 MHz fixed */
78
79 static int nowayout = WATCHDOG_NOWAYOUT;
80 static int heartbeat = DEFAULT_HEARTBEAT;
81
82 static DEFINE_SPINLOCK(io_lock);
83 static unsigned long wdt_status;
84 #define WDT_IN_USE        0
85 #define WDT_OK_TO_CLOSE   1
86 #define WDT_REGION_INITED 2
87 #define WDT_DEVICE_INITED 3
88
89 static unsigned long boot_status;
90
91 static struct resource  *wdt_mem;
92 static void __iomem     *wdt_base;
93 struct clk              *wdt_clk;
94
95 static void wdt_enable(void)
96 {
97         spin_lock(&io_lock);
98
99         if (wdt_clk)
100                 clk_set_rate(wdt_clk, 1);
101
102         /* stop counter, initiate counter reset */
103         __raw_writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
104         /*wait for reset to complete. 100% guarantee event */
105         while (__raw_readl(WDTIM_COUNTER(wdt_base)))
106                 cpu_relax();
107         /* internal and external reset, stop after that */
108         __raw_writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0,
109                 WDTIM_MCTRL(wdt_base));
110         /* configure match output */
111         __raw_writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
112         /* clear interrupt, just in case */
113         __raw_writel(MATCH_INT, WDTIM_INT(wdt_base));
114         /* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
115         __raw_writel(0xFFFF, WDTIM_PULSE(wdt_base));
116         __raw_writel(heartbeat * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
117         /*enable counter, stop when debugger active */
118         __raw_writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
119
120         spin_unlock(&io_lock);
121 }
122
123 static void wdt_disable(void)
124 {
125         spin_lock(&io_lock);
126
127         __raw_writel(0, WDTIM_CTRL(wdt_base));  /*stop counter */
128         if (wdt_clk)
129                 clk_set_rate(wdt_clk, 0);
130
131         spin_unlock(&io_lock);
132 }
133
134 static int pnx4008_wdt_open(struct inode *inode, struct file *file)
135 {
136         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
137                 return -EBUSY;
138
139         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
140
141         wdt_enable();
142
143         return nonseekable_open(inode, file);
144 }
145
146 static ssize_t pnx4008_wdt_write(struct file *file, const char *data,
147                                         size_t len, loff_t *ppos)
148 {
149         if (len) {
150                 if (!nowayout) {
151                         size_t i;
152
153                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
154
155                         for (i = 0; i != len; i++) {
156                                 char c;
157
158                                 if (get_user(c, data + i))
159                                         return -EFAULT;
160                                 if (c == 'V')
161                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
162                         }
163                 }
164                 wdt_enable();
165         }
166
167         return len;
168 }
169
170 static const struct watchdog_info ident = {
171         .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
172             WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
173         .identity = "PNX4008 Watchdog",
174 };
175
176 static long pnx4008_wdt_ioctl(struct file *file, unsigned int cmd,
177                                 unsigned long arg)
178 {
179         int ret = -ENOTTY;
180         int time;
181
182         switch (cmd) {
183         case WDIOC_GETSUPPORT:
184                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
185                                    sizeof(ident)) ? -EFAULT : 0;
186                 break;
187
188         case WDIOC_GETSTATUS:
189                 ret = put_user(0, (int *)arg);
190                 break;
191
192         case WDIOC_GETBOOTSTATUS:
193                 ret = put_user(boot_status, (int *)arg);
194                 break;
195
196         case WDIOC_KEEPALIVE:
197                 wdt_enable();
198                 ret = 0;
199                 break;
200
201         case WDIOC_SETTIMEOUT:
202                 ret = get_user(time, (int *)arg);
203                 if (ret)
204                         break;
205
206                 if (time <= 0 || time > MAX_HEARTBEAT) {
207                         ret = -EINVAL;
208                         break;
209                 }
210
211                 heartbeat = time;
212                 wdt_enable();
213                 /* Fall through */
214
215         case WDIOC_GETTIMEOUT:
216                 ret = put_user(heartbeat, (int *)arg);
217                 break;
218         }
219         return ret;
220 }
221
222 static int pnx4008_wdt_release(struct inode *inode, struct file *file)
223 {
224         if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status))
225                 printk(KERN_WARNING "WATCHDOG: Device closed unexpectdly\n");
226
227         wdt_disable();
228         clear_bit(WDT_IN_USE, &wdt_status);
229         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
230
231         return 0;
232 }
233
234 static const struct file_operations pnx4008_wdt_fops = {
235         .owner = THIS_MODULE,
236         .llseek = no_llseek,
237         .write = pnx4008_wdt_write,
238         .unlocked_ioctl = pnx4008_wdt_ioctl,
239         .open = pnx4008_wdt_open,
240         .release = pnx4008_wdt_release,
241 };
242
243 static struct miscdevice pnx4008_wdt_miscdev = {
244         .minor = WATCHDOG_MINOR,
245         .name = "watchdog",
246         .fops = &pnx4008_wdt_fops,
247 };
248
249 static int pnx4008_wdt_probe(struct platform_device *pdev)
250 {
251         int ret = 0, size;
252         struct resource *res;
253
254         if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
255                 heartbeat = DEFAULT_HEARTBEAT;
256
257         printk(KERN_INFO MODULE_NAME
258                 "PNX4008 Watchdog Timer: heartbeat %d sec\n", heartbeat);
259
260         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
261         if (res == NULL) {
262                 printk(KERN_INFO MODULE_NAME
263                         "failed to get memory region resouce\n");
264                 return -ENOENT;
265         }
266
267         size = res->end - res->start + 1;
268         wdt_mem = request_mem_region(res->start, size, pdev->name);
269
270         if (wdt_mem == NULL) {
271                 printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
272                 return -ENOENT;
273         }
274         wdt_base = (void __iomem *)IO_ADDRESS(res->start);
275
276         wdt_clk = clk_get(&pdev->dev, "wdt_ck");
277         if (IS_ERR(wdt_clk)) {
278                 ret = PTR_ERR(wdt_clk);
279                 release_resource(wdt_mem);
280                 kfree(wdt_mem);
281                 goto out;
282         } else
283                 clk_set_rate(wdt_clk, 1);
284
285         ret = misc_register(&pnx4008_wdt_miscdev);
286         if (ret < 0) {
287                 printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
288                 release_resource(wdt_mem);
289                 kfree(wdt_mem);
290                 clk_set_rate(wdt_clk, 0);
291         } else {
292                 boot_status = (__raw_readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
293                     WDIOF_CARDRESET : 0;
294                 wdt_disable();          /*disable for now */
295                 set_bit(WDT_DEVICE_INITED, &wdt_status);
296         }
297
298 out:
299         return ret;
300 }
301
302 static int pnx4008_wdt_remove(struct platform_device *pdev)
303 {
304         misc_deregister(&pnx4008_wdt_miscdev);
305         if (wdt_clk) {
306                 clk_set_rate(wdt_clk, 0);
307                 clk_put(wdt_clk);
308                 wdt_clk = NULL;
309         }
310         if (wdt_mem) {
311                 release_resource(wdt_mem);
312                 kfree(wdt_mem);
313                 wdt_mem = NULL;
314         }
315         return 0;
316 }
317
318 static struct platform_driver platform_wdt_driver = {
319         .driver = {
320                 .name = "watchdog",
321                 .owner  = THIS_MODULE,
322         },
323         .probe = pnx4008_wdt_probe,
324         .remove = pnx4008_wdt_remove,
325 };
326
327 static int __init pnx4008_wdt_init(void)
328 {
329         return platform_driver_register(&platform_wdt_driver);
330 }
331
332 static void __exit pnx4008_wdt_exit(void)
333 {
334         platform_driver_unregister(&platform_wdt_driver);
335 }
336
337 module_init(pnx4008_wdt_init);
338 module_exit(pnx4008_wdt_exit);
339
340 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
341 MODULE_DESCRIPTION("PNX4008 Watchdog Driver");
342
343 module_param(heartbeat, int, 0);
344 MODULE_PARM_DESC(heartbeat,
345                  "Watchdog heartbeat period in seconds from 1 to "
346                  __MODULE_STRING(MAX_HEARTBEAT) ", default "
347                  __MODULE_STRING(DEFAULT_HEARTBEAT));
348
349 module_param(nowayout, int, 0);
350 MODULE_PARM_DESC(nowayout,
351                  "Set to 1 to keep watchdog running after device release");
352
353 MODULE_LICENSE("GPL");
354 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
355 MODULE_ALIAS("platform:watchdog");