1 /*
2 * Broadcom BCM63xx SoC watchdog driver
3 *
4 * Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
5 * Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/bitops.h>
16 #include <linux/errno.h>
17 #include <linux/fs.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/miscdevice.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/types.h>
24 #include <linux/uaccess.h>
25 #include <linux/watchdog.h>
26 #include <linux/timer.h>
27 #include <linux/jiffies.h>
28 #include <linux/interrupt.h>
29 #include <linux/ptrace.h>
30 #include <linux/resource.h>
31 #include <linux/platform_device.h>
32
33 #include <bcm63xx_cpu.h>
34 #include <bcm63xx_io.h>
35 #include <bcm63xx_regs.h>
36 #include <bcm63xx_timer.h>
37
38 #define PFX KBUILD_MODNAME
39
40 #define WDT_HZ 50000000 /* Fclk */
41 #define WDT_DEFAULT_TIME 30 /* seconds */
42 #define WDT_MAX_TIME 256 /* seconds */
43
44 static struct {
45 void __iomem *regs;
46 struct timer_list timer;
47 int default_ticks;
48 unsigned long inuse;
49 atomic_t ticks;
50 } bcm63xx_wdt_device;
51
52 static int expect_close;
53
54 static int wdt_time = WDT_DEFAULT_TIME;
55 static bool nowayout = WATCHDOG_NOWAYOUT;
56 module_param(nowayout, bool, 0);
57 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
58 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
59
60 /* HW functions */
bcm63xx_wdt_hw_start(void)61 static void bcm63xx_wdt_hw_start(void)
62 {
63 bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
64 bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
65 bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
66 }
67
bcm63xx_wdt_hw_stop(void)68 static void bcm63xx_wdt_hw_stop(void)
69 {
70 bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
71 bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
72 }
73
bcm63xx_wdt_isr(void * data)74 static void bcm63xx_wdt_isr(void *data)
75 {
76 struct pt_regs *regs = get_irq_regs();
77
78 die(PFX " fire", regs);
79 }
80
bcm63xx_timer_tick(unsigned long unused)81 static void bcm63xx_timer_tick(unsigned long unused)
82 {
83 if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
84 bcm63xx_wdt_hw_start();
85 mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
86 } else
87 pr_crit("watchdog will restart system\n");
88 }
89
bcm63xx_wdt_pet(void)90 static void bcm63xx_wdt_pet(void)
91 {
92 atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
93 }
94
bcm63xx_wdt_start(void)95 static void bcm63xx_wdt_start(void)
96 {
97 bcm63xx_wdt_pet();
98 bcm63xx_timer_tick(0);
99 }
100
bcm63xx_wdt_pause(void)101 static void bcm63xx_wdt_pause(void)
102 {
103 del_timer_sync(&bcm63xx_wdt_device.timer);
104 bcm63xx_wdt_hw_stop();
105 }
106
bcm63xx_wdt_settimeout(int new_time)107 static int bcm63xx_wdt_settimeout(int new_time)
108 {
109 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
110 return -EINVAL;
111
112 wdt_time = new_time;
113
114 return 0;
115 }
116
bcm63xx_wdt_open(struct inode * inode,struct file * file)117 static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
118 {
119 if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
120 return -EBUSY;
121
122 bcm63xx_wdt_start();
123 return nonseekable_open(inode, file);
124 }
125
bcm63xx_wdt_release(struct inode * inode,struct file * file)126 static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
127 {
128 if (expect_close == 42)
129 bcm63xx_wdt_pause();
130 else {
131 pr_crit("Unexpected close, not stopping watchdog!\n");
132 bcm63xx_wdt_start();
133 }
134 clear_bit(0, &bcm63xx_wdt_device.inuse);
135 expect_close = 0;
136 return 0;
137 }
138
bcm63xx_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)139 static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
140 size_t len, loff_t *ppos)
141 {
142 if (len) {
143 if (!nowayout) {
144 size_t i;
145
146 /* In case it was set long ago */
147 expect_close = 0;
148
149 for (i = 0; i != len; i++) {
150 char c;
151 if (get_user(c, data + i))
152 return -EFAULT;
153 if (c == 'V')
154 expect_close = 42;
155 }
156 }
157 bcm63xx_wdt_pet();
158 }
159 return len;
160 }
161
162 static struct watchdog_info bcm63xx_wdt_info = {
163 .identity = PFX,
164 .options = WDIOF_SETTIMEOUT |
165 WDIOF_KEEPALIVEPING |
166 WDIOF_MAGICCLOSE,
167 };
168
169
bcm63xx_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)170 static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
171 unsigned long arg)
172 {
173 void __user *argp = (void __user *)arg;
174 int __user *p = argp;
175 int new_value, retval = -EINVAL;
176
177 switch (cmd) {
178 case WDIOC_GETSUPPORT:
179 return copy_to_user(argp, &bcm63xx_wdt_info,
180 sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
181
182 case WDIOC_GETSTATUS:
183 case WDIOC_GETBOOTSTATUS:
184 return put_user(0, p);
185
186 case WDIOC_SETOPTIONS:
187 if (get_user(new_value, p))
188 return -EFAULT;
189
190 if (new_value & WDIOS_DISABLECARD) {
191 bcm63xx_wdt_pause();
192 retval = 0;
193 }
194 if (new_value & WDIOS_ENABLECARD) {
195 bcm63xx_wdt_start();
196 retval = 0;
197 }
198
199 return retval;
200
201 case WDIOC_KEEPALIVE:
202 bcm63xx_wdt_pet();
203 return 0;
204
205 case WDIOC_SETTIMEOUT:
206 if (get_user(new_value, p))
207 return -EFAULT;
208
209 if (bcm63xx_wdt_settimeout(new_value))
210 return -EINVAL;
211
212 bcm63xx_wdt_pet();
213
214 case WDIOC_GETTIMEOUT:
215 return put_user(wdt_time, p);
216
217 default:
218 return -ENOTTY;
219
220 }
221 }
222
223 static const struct file_operations bcm63xx_wdt_fops = {
224 .owner = THIS_MODULE,
225 .llseek = no_llseek,
226 .write = bcm63xx_wdt_write,
227 .unlocked_ioctl = bcm63xx_wdt_ioctl,
228 .open = bcm63xx_wdt_open,
229 .release = bcm63xx_wdt_release,
230 };
231
232 static struct miscdevice bcm63xx_wdt_miscdev = {
233 .minor = WATCHDOG_MINOR,
234 .name = "watchdog",
235 .fops = &bcm63xx_wdt_fops,
236 };
237
238
bcm63xx_wdt_probe(struct platform_device * pdev)239 static int bcm63xx_wdt_probe(struct platform_device *pdev)
240 {
241 int ret;
242 struct resource *r;
243
244 setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
245
246 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
247 if (!r) {
248 dev_err(&pdev->dev, "failed to get resources\n");
249 return -ENODEV;
250 }
251
252 bcm63xx_wdt_device.regs = ioremap_nocache(r->start, resource_size(r));
253 if (!bcm63xx_wdt_device.regs) {
254 dev_err(&pdev->dev, "failed to remap I/O resources\n");
255 return -ENXIO;
256 }
257
258 ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
259 if (ret < 0) {
260 dev_err(&pdev->dev, "failed to register wdt timer isr\n");
261 goto unmap;
262 }
263
264 if (bcm63xx_wdt_settimeout(wdt_time)) {
265 bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
266 dev_info(&pdev->dev,
267 ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
268 wdt_time);
269 }
270
271 ret = misc_register(&bcm63xx_wdt_miscdev);
272 if (ret < 0) {
273 dev_err(&pdev->dev, "failed to register watchdog device\n");
274 goto unregister_timer;
275 }
276
277 dev_info(&pdev->dev, " started, timer margin: %d sec\n",
278 WDT_DEFAULT_TIME);
279
280 return 0;
281
282 unregister_timer:
283 bcm63xx_timer_unregister(TIMER_WDT_ID);
284 unmap:
285 iounmap(bcm63xx_wdt_device.regs);
286 return ret;
287 }
288
bcm63xx_wdt_remove(struct platform_device * pdev)289 static int bcm63xx_wdt_remove(struct platform_device *pdev)
290 {
291 if (!nowayout)
292 bcm63xx_wdt_pause();
293
294 misc_deregister(&bcm63xx_wdt_miscdev);
295 bcm63xx_timer_unregister(TIMER_WDT_ID);
296 iounmap(bcm63xx_wdt_device.regs);
297 return 0;
298 }
299
bcm63xx_wdt_shutdown(struct platform_device * pdev)300 static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
301 {
302 bcm63xx_wdt_pause();
303 }
304
305 static struct platform_driver bcm63xx_wdt_driver = {
306 .probe = bcm63xx_wdt_probe,
307 .remove = bcm63xx_wdt_remove,
308 .shutdown = bcm63xx_wdt_shutdown,
309 .driver = {
310 .owner = THIS_MODULE,
311 .name = "bcm63xx-wdt",
312 }
313 };
314
315 module_platform_driver(bcm63xx_wdt_driver);
316
317 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
318 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
319 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
320 MODULE_LICENSE("GPL");
321 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
322 MODULE_ALIAS("platform:bcm63xx-wdt");
323