Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / drivers / watchdog / rc32434_wdt.c
blob3a75f3b53452cdb51f49882a26480cbcf8673fb9
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 #include <linux/module.h> /* For module specific items */
23 #include <linux/moduleparam.h> /* For new moduleparam's */
24 #include <linux/types.h> /* For standard types (like size_t) */
25 #include <linux/errno.h> /* For the -ENODEV/... values */
26 #include <linux/kernel.h> /* For printk/panic/... */
27 #include <linux/fs.h> /* For file operations */
28 #include <linux/miscdevice.h> /* For struct miscdevice */
29 #include <linux/watchdog.h> /* For the watchdog specific items */
30 #include <linux/init.h> /* For __init/__exit/... */
31 #include <linux/platform_device.h> /* For platform_driver framework */
32 #include <linux/spinlock.h> /* For spin_lock/spin_unlock/... */
33 #include <linux/uaccess.h> /* For copy_to_user/put_user/... */
34 #include <linux/io.h> /* For devm_ioremap_nocache */
36 #include <asm/mach-rc32434/integ.h> /* For the Watchdog registers */
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 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
67 static bool nowayout = WATCHDOG_NOWAYOUT;
68 module_param(nowayout, bool, 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 pr_err("timeout value must be between 0 and %d\n", max_to);
82 return -EINVAL;
84 timeout = new_timeout;
85 spin_lock(&rc32434_wdt_device.io_lock);
86 writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare);
87 spin_unlock(&rc32434_wdt_device.io_lock);
89 return 0;
92 static void rc32434_wdt_start(void)
94 u32 or, nand;
96 spin_lock(&rc32434_wdt_device.io_lock);
98 /* zero the counter before enabling */
99 writel(0, &wdt_reg->wtcount);
101 /* don't generate a non-maskable interrupt,
102 * do a warm reset instead */
103 nand = 1 << RC32434_ERR_WNE;
104 or = 1 << RC32434_ERR_WRE;
106 /* reset the ERRCS timeout bit in case it's set */
107 nand |= 1 << RC32434_ERR_WTO;
109 SET_BITS(wdt_reg->errcs, or, nand);
111 /* set the timeout (either default or based on module param) */
112 rc32434_wdt_set(timeout);
114 /* reset WTC timeout bit and enable WDT */
115 nand = 1 << RC32434_WTC_TO;
116 or = 1 << RC32434_WTC_EN;
118 SET_BITS(wdt_reg->wtc, or, nand);
120 spin_unlock(&rc32434_wdt_device.io_lock);
121 pr_info("Started watchdog timer\n");
124 static void rc32434_wdt_stop(void)
126 spin_lock(&rc32434_wdt_device.io_lock);
128 /* Disable WDT */
129 SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN);
131 spin_unlock(&rc32434_wdt_device.io_lock);
132 pr_info("Stopped watchdog timer\n");
135 static void rc32434_wdt_ping(void)
137 spin_lock(&rc32434_wdt_device.io_lock);
138 writel(0, &wdt_reg->wtcount);
139 spin_unlock(&rc32434_wdt_device.io_lock);
142 static int rc32434_wdt_open(struct inode *inode, struct file *file)
144 if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
145 return -EBUSY;
147 if (nowayout)
148 __module_get(THIS_MODULE);
150 rc32434_wdt_start();
151 rc32434_wdt_ping();
153 return nonseekable_open(inode, file);
156 static int rc32434_wdt_release(struct inode *inode, struct file *file)
158 if (expect_close == 42) {
159 rc32434_wdt_stop();
160 module_put(THIS_MODULE);
161 } else {
162 pr_crit("device closed unexpectedly. WDT will not stop!\n");
163 rc32434_wdt_ping();
165 clear_bit(0, &rc32434_wdt_device.inuse);
166 return 0;
169 static ssize_t rc32434_wdt_write(struct file *file, const char *data,
170 size_t len, loff_t *ppos)
172 if (len) {
173 if (!nowayout) {
174 size_t i;
176 /* In case it was set long ago */
177 expect_close = 0;
179 for (i = 0; i != len; i++) {
180 char c;
181 if (get_user(c, data + i))
182 return -EFAULT;
183 if (c == 'V')
184 expect_close = 42;
187 rc32434_wdt_ping();
188 return len;
190 return 0;
193 static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
194 unsigned long arg)
196 void __user *argp = (void __user *)arg;
197 int new_timeout;
198 unsigned int value;
199 static const struct watchdog_info ident = {
200 .options = WDIOF_SETTIMEOUT |
201 WDIOF_KEEPALIVEPING |
202 WDIOF_MAGICCLOSE,
203 .identity = "RC32434_WDT Watchdog",
205 switch (cmd) {
206 case WDIOC_GETSUPPORT:
207 if (copy_to_user(argp, &ident, sizeof(ident)))
208 return -EFAULT;
209 break;
210 case WDIOC_GETSTATUS:
211 case WDIOC_GETBOOTSTATUS:
212 value = 0;
213 if (copy_to_user(argp, &value, sizeof(int)))
214 return -EFAULT;
215 break;
216 case WDIOC_SETOPTIONS:
217 if (copy_from_user(&value, argp, sizeof(int)))
218 return -EFAULT;
219 switch (value) {
220 case WDIOS_ENABLECARD:
221 rc32434_wdt_start();
222 break;
223 case WDIOS_DISABLECARD:
224 rc32434_wdt_stop();
225 break;
226 default:
227 return -EINVAL;
229 break;
230 case WDIOC_KEEPALIVE:
231 rc32434_wdt_ping();
232 break;
233 case WDIOC_SETTIMEOUT:
234 if (copy_from_user(&new_timeout, argp, sizeof(int)))
235 return -EFAULT;
236 if (rc32434_wdt_set(new_timeout))
237 return -EINVAL;
238 /* Fall through */
239 case WDIOC_GETTIMEOUT:
240 return copy_to_user(argp, &timeout, sizeof(int)) ? -EFAULT : 0;
241 default:
242 return -ENOTTY;
245 return 0;
248 static const struct file_operations rc32434_wdt_fops = {
249 .owner = THIS_MODULE,
250 .llseek = no_llseek,
251 .write = rc32434_wdt_write,
252 .unlocked_ioctl = rc32434_wdt_ioctl,
253 .open = rc32434_wdt_open,
254 .release = rc32434_wdt_release,
257 static struct miscdevice rc32434_wdt_miscdev = {
258 .minor = WATCHDOG_MINOR,
259 .name = "watchdog",
260 .fops = &rc32434_wdt_fops,
263 static int rc32434_wdt_probe(struct platform_device *pdev)
265 int ret;
266 struct resource *r;
268 r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res");
269 if (!r) {
270 pr_err("failed to retrieve resources\n");
271 return -ENODEV;
274 wdt_reg = devm_ioremap_nocache(&pdev->dev, r->start, resource_size(r));
275 if (!wdt_reg) {
276 pr_err("failed to remap I/O resources\n");
277 return -ENXIO;
280 spin_lock_init(&rc32434_wdt_device.io_lock);
282 /* Make sure the watchdog is not running */
283 rc32434_wdt_stop();
285 /* Check that the heartbeat value is within it's range;
286 * if not reset to the default */
287 if (rc32434_wdt_set(timeout)) {
288 rc32434_wdt_set(WATCHDOG_TIMEOUT);
289 pr_info("timeout value must be between 0 and %d\n",
290 WTCOMP2SEC((u32)-1));
293 ret = misc_register(&rc32434_wdt_miscdev);
294 if (ret < 0) {
295 pr_err("failed to register watchdog device\n");
296 return ret;
299 pr_info("Watchdog Timer version " VERSION ", timer margin: %d sec\n",
300 timeout);
302 return 0;
305 static int rc32434_wdt_remove(struct platform_device *pdev)
307 misc_deregister(&rc32434_wdt_miscdev);
308 return 0;
311 static void rc32434_wdt_shutdown(struct platform_device *pdev)
313 rc32434_wdt_stop();
316 static struct platform_driver rc32434_wdt_driver = {
317 .probe = rc32434_wdt_probe,
318 .remove = rc32434_wdt_remove,
319 .shutdown = rc32434_wdt_shutdown,
320 .driver = {
321 .name = "rc32434_wdt",
325 module_platform_driver(rc32434_wdt_driver);
327 MODULE_AUTHOR("Ondrej Zajicek <santiago@crfreenet.org>,"
328 "Florian Fainelli <florian@openwrt.org>");
329 MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
330 MODULE_LICENSE("GPL");