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/io.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 unsigned long inuse;
48 atomic_t ticks;
49 } bcm63xx_wdt_device;
50
51 static int expect_close;
52
53 static int wdt_time = WDT_DEFAULT_TIME;
54 static bool nowayout = WATCHDOG_NOWAYOUT;
55 module_param(nowayout, bool, 0);
56 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
57 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
58
59 /* HW functions */
bcm63xx_wdt_hw_start(void)60 static void bcm63xx_wdt_hw_start(void)
61 {
62 bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
63 bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
64 bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
65 }
66
bcm63xx_wdt_hw_stop(void)67 static void bcm63xx_wdt_hw_stop(void)
68 {
69 bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
70 bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
71 }
72
bcm63xx_wdt_isr(void * data)73 static void bcm63xx_wdt_isr(void *data)
74 {
75 struct pt_regs *regs = get_irq_regs();
76
77 die(PFX " fire", regs);
78 }
79
bcm63xx_timer_tick(unsigned long unused)80 static void bcm63xx_timer_tick(unsigned long unused)
81 {
82 if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
83 bcm63xx_wdt_hw_start();
84 mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
85 } else
86 pr_crit("watchdog will restart system\n");
87 }
88
bcm63xx_wdt_pet(void)89 static void bcm63xx_wdt_pet(void)
90 {
91 atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
92 }
93
bcm63xx_wdt_start(void)94 static void bcm63xx_wdt_start(void)
95 {
96 bcm63xx_wdt_pet();
97 bcm63xx_timer_tick(0);
98 }
99
bcm63xx_wdt_pause(void)100 static void bcm63xx_wdt_pause(void)
101 {
102 del_timer_sync(&bcm63xx_wdt_device.timer);
103 bcm63xx_wdt_hw_stop();
104 }
105
bcm63xx_wdt_settimeout(int new_time)106 static int bcm63xx_wdt_settimeout(int new_time)
107 {
108 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
109 return -EINVAL;
110
111 wdt_time = new_time;
112
113 return 0;
114 }
115
bcm63xx_wdt_open(struct inode * inode,struct file * file)116 static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
117 {
118 if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
119 return -EBUSY;
120
121 bcm63xx_wdt_start();
122 return nonseekable_open(inode, file);
123 }
124
bcm63xx_wdt_release(struct inode * inode,struct file * file)125 static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
126 {
127 if (expect_close == 42)
128 bcm63xx_wdt_pause();
129 else {
130 pr_crit("Unexpected close, not stopping watchdog!\n");
131 bcm63xx_wdt_start();
132 }
133 clear_bit(0, &bcm63xx_wdt_device.inuse);
134 expect_close = 0;
135 return 0;
136 }
137
bcm63xx_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)138 static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
139 size_t len, loff_t *ppos)
140 {
141 if (len) {
142 if (!nowayout) {
143 size_t i;
144
145 /* In case it was set long ago */
146 expect_close = 0;
147
148 for (i = 0; i != len; i++) {
149 char c;
150 if (get_user(c, data + i))
151 return -EFAULT;
152 if (c == 'V')
153 expect_close = 42;
154 }
155 }
156 bcm63xx_wdt_pet();
157 }
158 return len;
159 }
160
161 static struct watchdog_info bcm63xx_wdt_info = {
162 .identity = PFX,
163 .options = WDIOF_SETTIMEOUT |
164 WDIOF_KEEPALIVEPING |
165 WDIOF_MAGICCLOSE,
166 };
167
168
bcm63xx_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)169 static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
170 unsigned long arg)
171 {
172 void __user *argp = (void __user *)arg;
173 int __user *p = argp;
174 int new_value, retval = -EINVAL;
175
176 switch (cmd) {
177 case WDIOC_GETSUPPORT:
178 return copy_to_user(argp, &bcm63xx_wdt_info,
179 sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
180
181 case WDIOC_GETSTATUS:
182 case WDIOC_GETBOOTSTATUS:
183 return put_user(0, p);
184
185 case WDIOC_SETOPTIONS:
186 if (get_user(new_value, p))
187 return -EFAULT;
188
189 if (new_value & WDIOS_DISABLECARD) {
190 bcm63xx_wdt_pause();
191 retval = 0;
192 }
193 if (new_value & WDIOS_ENABLECARD) {
194 bcm63xx_wdt_start();
195 retval = 0;
196 }
197
198 return retval;
199
200 case WDIOC_KEEPALIVE:
201 bcm63xx_wdt_pet();
202 return 0;
203
204 case WDIOC_SETTIMEOUT:
205 if (get_user(new_value, p))
206 return -EFAULT;
207
208 if (bcm63xx_wdt_settimeout(new_value))
209 return -EINVAL;
210
211 bcm63xx_wdt_pet();
212
213 case WDIOC_GETTIMEOUT:
214 return put_user(wdt_time, p);
215
216 default:
217 return -ENOTTY;
218
219 }
220 }
221
222 static const struct file_operations bcm63xx_wdt_fops = {
223 .owner = THIS_MODULE,
224 .llseek = no_llseek,
225 .write = bcm63xx_wdt_write,
226 .unlocked_ioctl = bcm63xx_wdt_ioctl,
227 .open = bcm63xx_wdt_open,
228 .release = bcm63xx_wdt_release,
229 };
230
231 static struct miscdevice bcm63xx_wdt_miscdev = {
232 .minor = WATCHDOG_MINOR,
233 .name = "watchdog",
234 .fops = &bcm63xx_wdt_fops,
235 };
236
237
bcm63xx_wdt_probe(struct platform_device * pdev)238 static int bcm63xx_wdt_probe(struct platform_device *pdev)
239 {
240 int ret;
241 struct resource *r;
242
243 setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
244
245 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
246 if (!r) {
247 dev_err(&pdev->dev, "failed to get resources\n");
248 return -ENODEV;
249 }
250
251 bcm63xx_wdt_device.regs = devm_ioremap_nocache(&pdev->dev, r->start,
252 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 return ret;
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 return ret;
285 }
286
bcm63xx_wdt_remove(struct platform_device * pdev)287 static int bcm63xx_wdt_remove(struct platform_device *pdev)
288 {
289 if (!nowayout)
290 bcm63xx_wdt_pause();
291
292 misc_deregister(&bcm63xx_wdt_miscdev);
293 bcm63xx_timer_unregister(TIMER_WDT_ID);
294 return 0;
295 }
296
bcm63xx_wdt_shutdown(struct platform_device * pdev)297 static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
298 {
299 bcm63xx_wdt_pause();
300 }
301
302 static struct platform_driver bcm63xx_wdt_driver = {
303 .probe = bcm63xx_wdt_probe,
304 .remove = bcm63xx_wdt_remove,
305 .shutdown = bcm63xx_wdt_shutdown,
306 .driver = {
307 .name = "bcm63xx-wdt",
308 }
309 };
310
311 module_platform_driver(bcm63xx_wdt_driver);
312
313 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
314 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
315 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
316 MODULE_LICENSE("GPL");
317 MODULE_ALIAS("platform:bcm63xx-wdt");
318