MINI2440: Rename the SoC tty names.
[linux-2.6/mini2440.git] / drivers / watchdog / rc32434_wdt.c
blobf6cccc9df022cbb55b04aa5fac43fcfd6413964c
1 /*
2 * IDT Interprise 79RC32434 watchdog driver
4 * Copyright (C) 2006, Ondrej Zajicek <santiago@crfreenet.org>
5 * Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
7 * based on
8 * SoftDog 0.05: A Software Watchdog Device
10 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
11 * All Rights Reserved.
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
20 #include <linux/module.h> /* For module specific items */
21 #include <linux/moduleparam.h> /* For new moduleparam's */
22 #include <linux/types.h> /* For standard types (like size_t) */
23 #include <linux/errno.h> /* For the -ENODEV/... values */
24 #include <linux/kernel.h> /* For printk/panic/... */
25 #include <linux/fs.h> /* For file operations */
26 #include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV
27 (WATCHDOG_MINOR) */
28 #include <linux/watchdog.h> /* For the watchdog specific items */
29 #include <linux/init.h> /* For __init/__exit/... */
30 #include <linux/platform_device.h> /* For platform_driver framework */
31 #include <linux/spinlock.h> /* For spin_lock/spin_unlock/... */
32 #include <linux/uaccess.h> /* For copy_to_user/put_user/... */
34 #include <asm/mach-rc32434/integ.h> /* For the Watchdog registers */
36 #define PFX KBUILD_MODNAME ": "
38 #define VERSION "1.0"
40 static struct {
41 unsigned long inuse;
42 spinlock_t io_lock;
43 } rc32434_wdt_device;
45 static struct integ __iomem *wdt_reg;
47 static int expect_close;
49 /* Board internal clock speed in Hz,
50 * the watchdog timer ticks at. */
51 extern unsigned int idt_cpu_freq;
53 /* translate wtcompare value to seconds and vice versa */
54 #define WTCOMP2SEC(x) (x / idt_cpu_freq)
55 #define SEC2WTCOMP(x) (x * idt_cpu_freq)
57 /* Use a default timeout of 20s. This should be
58 * safe for CPU clock speeds up to 400MHz, as
59 * ((2 ^ 32) - 1) / (400MHz / 2) = 21s. */
60 #define WATCHDOG_TIMEOUT 20
62 static int timeout = WATCHDOG_TIMEOUT;
63 module_param(timeout, int, 0);
64 MODULE_PARM_DESC(timeout, "Watchdog timeout value, in seconds (default="
65 WATCHDOG_TIMEOUT ")");
67 static int nowayout = WATCHDOG_NOWAYOUT;
68 module_param(nowayout, int, 0);
69 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
70 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
72 /* apply or and nand masks to data read from addr and write back */
73 #define SET_BITS(addr, or, nand) \
74 writel((readl(&addr) | or) & ~nand, &addr)
76 static int rc32434_wdt_set(int new_timeout)
78 int max_to = WTCOMP2SEC((u32)-1);
80 if (new_timeout < 0 || new_timeout > max_to) {
81 printk(KERN_ERR PFX "timeout value must be between 0 and %d",
82 max_to);
83 return -EINVAL;
85 timeout = new_timeout;
86 spin_lock(&rc32434_wdt_device.io_lock);
87 writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare);
88 spin_unlock(&rc32434_wdt_device.io_lock);
90 return 0;
93 static void rc32434_wdt_start(void)
95 u32 or, nand;
97 spin_lock(&rc32434_wdt_device.io_lock);
99 /* zero the counter before enabling */
100 writel(0, &wdt_reg->wtcount);
102 /* don't generate a non-maskable interrupt,
103 * do a warm reset instead */
104 nand = 1 << RC32434_ERR_WNE;
105 or = 1 << RC32434_ERR_WRE;
107 /* reset the ERRCS timeout bit in case it's set */
108 nand |= 1 << RC32434_ERR_WTO;
110 SET_BITS(wdt_reg->errcs, or, nand);
112 /* set the timeout (either default or based on module param) */
113 rc32434_wdt_set(timeout);
115 /* reset WTC timeout bit and enable WDT */
116 nand = 1 << RC32434_WTC_TO;
117 or = 1 << RC32434_WTC_EN;
119 SET_BITS(wdt_reg->wtc, or, nand);
121 spin_unlock(&rc32434_wdt_device.io_lock);
122 printk(KERN_INFO PFX "Started watchdog timer.\n");
125 static void rc32434_wdt_stop(void)
127 spin_lock(&rc32434_wdt_device.io_lock);
129 /* Disable WDT */
130 SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN);
132 spin_unlock(&rc32434_wdt_device.io_lock);
133 printk(KERN_INFO PFX "Stopped watchdog timer.\n");
136 static void rc32434_wdt_ping(void)
138 spin_lock(&rc32434_wdt_device.io_lock);
139 writel(0, &wdt_reg->wtcount);
140 spin_unlock(&rc32434_wdt_device.io_lock);
143 static int rc32434_wdt_open(struct inode *inode, struct file *file)
145 if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
146 return -EBUSY;
148 if (nowayout)
149 __module_get(THIS_MODULE);
151 rc32434_wdt_start();
152 rc32434_wdt_ping();
154 return nonseekable_open(inode, file);
157 static int rc32434_wdt_release(struct inode *inode, struct file *file)
159 if (expect_close == 42) {
160 rc32434_wdt_stop();
161 module_put(THIS_MODULE);
162 } else {
163 printk(KERN_CRIT PFX
164 "device closed unexpectedly. WDT will not stop!\n");
165 rc32434_wdt_ping();
167 clear_bit(0, &rc32434_wdt_device.inuse);
168 return 0;
171 static ssize_t rc32434_wdt_write(struct file *file, const char *data,
172 size_t len, loff_t *ppos)
174 if (len) {
175 if (!nowayout) {
176 size_t i;
178 /* In case it was set long ago */
179 expect_close = 0;
181 for (i = 0; i != len; i++) {
182 char c;
183 if (get_user(c, data + i))
184 return -EFAULT;
185 if (c == 'V')
186 expect_close = 42;
189 rc32434_wdt_ping();
190 return len;
192 return 0;
195 static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
196 unsigned long arg)
198 void __user *argp = (void __user *)arg;
199 int new_timeout;
200 unsigned int value;
201 static struct watchdog_info ident = {
202 .options = WDIOF_SETTIMEOUT |
203 WDIOF_KEEPALIVEPING |
204 WDIOF_MAGICCLOSE,
205 .identity = "RC32434_WDT Watchdog",
207 switch (cmd) {
208 case WDIOC_GETSUPPORT:
209 if (copy_to_user(argp, &ident, sizeof(ident)))
210 return -EFAULT;
211 break;
212 case WDIOC_GETSTATUS:
213 case WDIOC_GETBOOTSTATUS:
214 value = 0;
215 if (copy_to_user(argp, &value, sizeof(int)))
216 return -EFAULT;
217 break;
218 case WDIOC_SETOPTIONS:
219 if (copy_from_user(&value, argp, sizeof(int)))
220 return -EFAULT;
221 switch (value) {
222 case WDIOS_ENABLECARD:
223 rc32434_wdt_start();
224 break;
225 case WDIOS_DISABLECARD:
226 rc32434_wdt_stop();
227 break;
228 default:
229 return -EINVAL;
231 break;
232 case WDIOC_KEEPALIVE:
233 rc32434_wdt_ping();
234 break;
235 case WDIOC_SETTIMEOUT:
236 if (copy_from_user(&new_timeout, argp, sizeof(int)))
237 return -EFAULT;
238 if (rc32434_wdt_set(new_timeout))
239 return -EINVAL;
240 /* Fall through */
241 case WDIOC_GETTIMEOUT:
242 return copy_to_user(argp, &timeout, sizeof(int));
243 default:
244 return -ENOTTY;
247 return 0;
250 static const struct file_operations rc32434_wdt_fops = {
251 .owner = THIS_MODULE,
252 .llseek = no_llseek,
253 .write = rc32434_wdt_write,
254 .unlocked_ioctl = rc32434_wdt_ioctl,
255 .open = rc32434_wdt_open,
256 .release = rc32434_wdt_release,
259 static struct miscdevice rc32434_wdt_miscdev = {
260 .minor = WATCHDOG_MINOR,
261 .name = "watchdog",
262 .fops = &rc32434_wdt_fops,
265 static char banner[] __devinitdata = KERN_INFO PFX
266 "Watchdog Timer version " VERSION ", timer margin: %d sec\n";
268 static int __devinit rc32434_wdt_probe(struct platform_device *pdev)
270 int ret;
271 struct resource *r;
273 r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res");
274 if (!r) {
275 printk(KERN_ERR PFX "failed to retrieve resources\n");
276 return -ENODEV;
279 wdt_reg = ioremap_nocache(r->start, r->end - r->start);
280 if (!wdt_reg) {
281 printk(KERN_ERR PFX "failed to remap I/O resources\n");
282 return -ENXIO;
285 spin_lock_init(&rc32434_wdt_device.io_lock);
287 /* Make sure the watchdog is not running */
288 rc32434_wdt_stop();
290 /* Check that the heartbeat value is within it's range;
291 * if not reset to the default */
292 if (rc32434_wdt_set(timeout)) {
293 rc32434_wdt_set(WATCHDOG_TIMEOUT);
294 printk(KERN_INFO PFX
295 "timeout value must be between 0 and %d\n",
296 WTCOMP2SEC((u32)-1));
299 ret = misc_register(&rc32434_wdt_miscdev);
300 if (ret < 0) {
301 printk(KERN_ERR PFX "failed to register watchdog device\n");
302 goto unmap;
305 printk(banner, timeout);
307 return 0;
309 unmap:
310 iounmap(wdt_reg);
311 return ret;
314 static int __devexit rc32434_wdt_remove(struct platform_device *pdev)
316 misc_deregister(&rc32434_wdt_miscdev);
317 iounmap(wdt_reg);
318 return 0;
321 static void rc32434_wdt_shutdown(struct platform_device *pdev)
323 rc32434_wdt_stop();
326 static struct platform_driver rc32434_wdt_driver = {
327 .probe = rc32434_wdt_probe,
328 .remove = __devexit_p(rc32434_wdt_remove),
329 .shutdown = rc32434_wdt_shutdown,
330 .driver = {
331 .name = "rc32434_wdt",
335 static int __init rc32434_wdt_init(void)
337 return platform_driver_register(&rc32434_wdt_driver);
340 static void __exit rc32434_wdt_exit(void)
342 platform_driver_unregister(&rc32434_wdt_driver);
345 module_init(rc32434_wdt_init);
346 module_exit(rc32434_wdt_exit);
348 MODULE_AUTHOR("Ondrej Zajicek <santiago@crfreenet.org>,"
349 "Florian Fainelli <florian@openwrt.org>");
350 MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
351 MODULE_LICENSE("GPL");
352 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);