wdt:lpc32xx:Fix no-wayout on close
[linux-2.6.34-lpc32xx.git] / 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 <linux/slab.h>
34 #include <mach/hardware.h>
35
36 #define MODULE_NAME "PNX4008-WDT: "
37
38 /* WatchDog Timer - Chapter 23 Page 207 */
39
40 #define DEFAULT_HEARTBEAT 19
41 #define MAX_HEARTBEAT     60
42
43 /* Watchdog timer register set definition */
44 #define WDTIM_INT(p)     ((p) + 0x0)
45 #define WDTIM_CTRL(p)    ((p) + 0x4)
46 #define WDTIM_COUNTER(p) ((p) + 0x8)
47 #define WDTIM_MCTRL(p)   ((p) + 0xC)
48 #define WDTIM_MATCH0(p)  ((p) + 0x10)
49 #define WDTIM_EMR(p)     ((p) + 0x14)
50 #define WDTIM_PULSE(p)   ((p) + 0x18)
51 #define WDTIM_RES(p)     ((p) + 0x1C)
52
53 /* WDTIM_INT bit definitions */
54 #define MATCH_INT      1
55
56 /* WDTIM_CTRL bit definitions */
57 #define COUNT_ENAB     1
58 #define RESET_COUNT    (1 << 1)
59 #define DEBUG_EN       (1 << 2)
60
61 /* WDTIM_MCTRL bit definitions */
62 #define MR0_INT        1
63 #undef  RESET_COUNT0
64 #define RESET_COUNT0   (1 << 2)
65 #define STOP_COUNT0    (1 << 2)
66 #define M_RES1         (1 << 3)
67 #define M_RES2         (1 << 4)
68 #define RESFRC1        (1 << 5)
69 #define RESFRC2        (1 << 6)
70
71 /* WDTIM_EMR bit definitions */
72 #define EXT_MATCH0      1
73 #define MATCH_OUTPUT_HIGH (2 << 4)      /*a MATCH_CTRL setting */
74
75 /* WDTIM_RES bit definitions */
76 #define WDOG_RESET      1       /* read only */
77
78 #define WDOG_COUNTER_RATE 13000000      /*the counter clock is 13 MHz fixed */
79
80 static int nowayout = WATCHDOG_NOWAYOUT;
81 static int heartbeat = DEFAULT_HEARTBEAT;
82
83 static DEFINE_SPINLOCK(io_lock);
84 static unsigned long wdt_status;
85 #define WDT_IN_USE        0
86 #define WDT_OK_TO_CLOSE   1
87 #define WDT_REGION_INITED 2
88 #define WDT_DEVICE_INITED 3
89
90 static unsigned long boot_status;
91
92 static struct resource  *wdt_mem;
93 static void __iomem     *wdt_base;
94 struct clk              *wdt_clk;
95
96 static void wdt_enable(void)
97 {
98         spin_lock(&io_lock);
99
100         /* stop counter, initiate counter reset */
101         __raw_writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
102         /*wait for reset to complete. 100% guarantee event */
103         while (__raw_readl(WDTIM_COUNTER(wdt_base)))
104                 cpu_relax();
105         /* internal and external reset, stop after that */
106         __raw_writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0,
107                 WDTIM_MCTRL(wdt_base));
108         /* configure match output */
109         __raw_writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
110         /* clear interrupt, just in case */
111         __raw_writel(MATCH_INT, WDTIM_INT(wdt_base));
112         /* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
113         __raw_writel(0xFFFF, WDTIM_PULSE(wdt_base));
114         __raw_writel(heartbeat * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
115         /*enable counter, stop when debugger active */
116         __raw_writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
117
118         spin_unlock(&io_lock);
119 }
120
121 static void wdt_disable(void)
122 {
123         spin_lock(&io_lock);
124
125         __raw_writel(0, WDTIM_CTRL(wdt_base));  /*stop counter */
126
127         spin_unlock(&io_lock);
128 }
129
130 static int pnx4008_wdt_open(struct inode *inode, struct file *file)
131 {
132         int ret;
133
134         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
135                 return -EBUSY;
136
137         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
138
139         ret = clk_enable(wdt_clk);
140         if (ret) {
141                 clear_bit(WDT_IN_USE, &wdt_status);
142                 return ret;
143         }
144
145         wdt_enable();
146
147         return nonseekable_open(inode, file);
148 }
149
150 static ssize_t pnx4008_wdt_write(struct file *file, const char *data,
151                                         size_t len, loff_t *ppos)
152 {
153         if (len) {
154                 if (!nowayout) {
155                         size_t i;
156
157                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
158
159                         for (i = 0; i != len; i++) {
160                                 char c;
161
162                                 if (get_user(c, data + i))
163                                         return -EFAULT;
164                                 if (c == 'V')
165                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
166                         }
167                 }
168                 wdt_enable();
169         }
170
171         return len;
172 }
173
174 static const struct watchdog_info ident = {
175         .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
176             WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
177         .identity = "PNX4008 Watchdog",
178 };
179
180 static long pnx4008_wdt_ioctl(struct file *file, unsigned int cmd,
181                                 unsigned long arg)
182 {
183         int ret = -ENOTTY;
184         int time;
185
186         switch (cmd) {
187         case WDIOC_GETSUPPORT:
188                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
189                                    sizeof(ident)) ? -EFAULT : 0;
190                 break;
191
192         case WDIOC_GETSTATUS:
193                 ret = put_user(0, (int *)arg);
194                 break;
195
196         case WDIOC_GETBOOTSTATUS:
197                 ret = put_user(boot_status, (int *)arg);
198                 break;
199
200         case WDIOC_KEEPALIVE:
201                 wdt_enable();
202                 ret = 0;
203                 break;
204
205         case WDIOC_SETTIMEOUT:
206                 ret = get_user(time, (int *)arg);
207                 if (ret)
208                         break;
209
210                 if (time <= 0 || time > MAX_HEARTBEAT) {
211                         ret = -EINVAL;
212                         break;
213                 }
214
215                 heartbeat = time;
216                 wdt_enable();
217                 /* Fall through */
218
219         case WDIOC_GETTIMEOUT:
220                 ret = put_user(heartbeat, (int *)arg);
221                 break;
222         }
223         return ret;
224 }
225
226 static int pnx4008_wdt_release(struct inode *inode, struct file *file)
227 {
228         if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status))
229                 printk(KERN_WARNING "WATCHDOG: Device closed unexpectdly\n");
230
231         /* We should not disable watchdog if nowayout is set */
232         if (nowayout)
233                 return 0;
234
235         wdt_disable();
236         clk_disable(wdt_clk);
237         clear_bit(WDT_IN_USE, &wdt_status);
238         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
239
240         return 0;
241 }
242
243 static const struct file_operations pnx4008_wdt_fops = {
244         .owner = THIS_MODULE,
245         .llseek = no_llseek,
246         .write = pnx4008_wdt_write,
247         .unlocked_ioctl = pnx4008_wdt_ioctl,
248         .open = pnx4008_wdt_open,
249         .release = pnx4008_wdt_release,
250 };
251
252 static struct miscdevice pnx4008_wdt_miscdev = {
253         .minor = WATCHDOG_MINOR,
254         .name = "watchdog",
255         .fops = &pnx4008_wdt_fops,
256 };
257
258 static int __devinit pnx4008_wdt_probe(struct platform_device *pdev)
259 {
260         int ret = 0, size;
261         struct resource *res;
262
263         if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
264                 heartbeat = DEFAULT_HEARTBEAT;
265
266         printk(KERN_INFO MODULE_NAME
267                 "PNX4008 Watchdog Timer: heartbeat %d sec\n", heartbeat);
268
269         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
270         if (res == NULL) {
271                 printk(KERN_INFO MODULE_NAME
272                         "failed to get memory region resouce\n");
273                 return -ENOENT;
274         }
275
276         size = resource_size(res);
277         wdt_mem = request_mem_region(res->start, size, pdev->name);
278
279         if (wdt_mem == NULL) {
280                 printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
281                 return -ENOENT;
282         }
283         wdt_base = (void __iomem *)IO_ADDRESS(res->start);
284
285         wdt_clk = clk_get(&pdev->dev, NULL);
286         if (IS_ERR(wdt_clk)) {
287                 ret = PTR_ERR(wdt_clk);
288                 release_resource(wdt_mem);
289                 kfree(wdt_mem);
290                 goto out;
291         }
292
293         ret = clk_enable(wdt_clk);
294         if (ret) {
295                 release_resource(wdt_mem);
296                 kfree(wdt_mem);
297                 goto out;
298         }
299
300         ret = misc_register(&pnx4008_wdt_miscdev);
301         if (ret < 0) {
302                 printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
303                 release_resource(wdt_mem);
304                 kfree(wdt_mem);
305                 clk_disable(wdt_clk);
306                 clk_put(wdt_clk);
307         } else {
308                 boot_status = (__raw_readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
309                     WDIOF_CARDRESET : 0;
310                 wdt_disable();          /*disable for now */
311                 clk_disable(wdt_clk);
312                 set_bit(WDT_DEVICE_INITED, &wdt_status);
313         }
314
315 out:
316         return ret;
317 }
318
319 static int __devexit pnx4008_wdt_remove(struct platform_device *pdev)
320 {
321         misc_deregister(&pnx4008_wdt_miscdev);
322
323         clk_disable(wdt_clk);
324         clk_put(wdt_clk);
325
326         if (wdt_mem) {
327                 release_resource(wdt_mem);
328                 kfree(wdt_mem);
329                 wdt_mem = NULL;
330         }
331         return 0;
332 }
333
334 static struct platform_driver platform_wdt_driver = {
335         .driver = {
336                 .name = "pnx4008-watchdog",
337                 .owner  = THIS_MODULE,
338         },
339         .probe = pnx4008_wdt_probe,
340         .remove = __devexit_p(pnx4008_wdt_remove),
341 };
342
343 static int __init pnx4008_wdt_init(void)
344 {
345         return platform_driver_register(&platform_wdt_driver);
346 }
347
348 static void __exit pnx4008_wdt_exit(void)
349 {
350         platform_driver_unregister(&platform_wdt_driver);
351 }
352
353 module_init(pnx4008_wdt_init);
354 module_exit(pnx4008_wdt_exit);
355
356 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
357 MODULE_DESCRIPTION("PNX4008 Watchdog Driver");
358
359 module_param(heartbeat, int, 0);
360 MODULE_PARM_DESC(heartbeat,
361                  "Watchdog heartbeat period in seconds from 1 to "
362                  __MODULE_STRING(MAX_HEARTBEAT) ", default "
363                  __MODULE_STRING(DEFAULT_HEARTBEAT));
364
365 module_param(nowayout, int, 0);
366 MODULE_PARM_DESC(nowayout,
367                  "Set to 1 to keep watchdog running after device release");
368
369 MODULE_LICENSE("GPL");
370 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
371 MODULE_ALIAS("platform:pnx4008-watchdog");