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1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  Broadcom BCM63xx SoC watchdog driver
4  *
5  *  Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
6  *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
7  *
8  */
9 
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 
12 #include <linux/bitops.h>
13 #include <linux/errno.h>
14 #include <linux/fs.h>
15 #include <linux/io.h>
16 #include <linux/kernel.h>
17 #include <linux/miscdevice.h>
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/types.h>
21 #include <linux/uaccess.h>
22 #include <linux/watchdog.h>
23 #include <linux/timer.h>
24 #include <linux/jiffies.h>
25 #include <linux/interrupt.h>
26 #include <linux/ptrace.h>
27 #include <linux/resource.h>
28 #include <linux/platform_device.h>
29 
30 #include <bcm63xx_cpu.h>
31 #include <bcm63xx_io.h>
32 #include <bcm63xx_regs.h>
33 #include <bcm63xx_timer.h>
34 
35 #define PFX KBUILD_MODNAME
36 
37 #define WDT_HZ		50000000 /* Fclk */
38 #define WDT_DEFAULT_TIME	30      /* seconds */
39 #define WDT_MAX_TIME		256     /* seconds */
40 
41 static struct {
42 	void __iomem *regs;
43 	struct timer_list timer;
44 	unsigned long inuse;
45 	atomic_t ticks;
46 } bcm63xx_wdt_device;
47 
48 static int expect_close;
49 
50 static int wdt_time = WDT_DEFAULT_TIME;
51 static bool nowayout = WATCHDOG_NOWAYOUT;
52 module_param(nowayout, bool, 0);
53 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
54 	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
55 
56 /* HW functions */
bcm63xx_wdt_hw_start(void)57 static void bcm63xx_wdt_hw_start(void)
58 {
59 	bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
60 	bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
61 	bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
62 }
63 
bcm63xx_wdt_hw_stop(void)64 static void bcm63xx_wdt_hw_stop(void)
65 {
66 	bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
67 	bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
68 }
69 
bcm63xx_wdt_isr(void * data)70 static void bcm63xx_wdt_isr(void *data)
71 {
72 	struct pt_regs *regs = get_irq_regs();
73 
74 	die(PFX " fire", regs);
75 }
76 
bcm63xx_timer_tick(struct timer_list * unused)77 static void bcm63xx_timer_tick(struct timer_list *unused)
78 {
79 	if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
80 		bcm63xx_wdt_hw_start();
81 		mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
82 	} else
83 		pr_crit("watchdog will restart system\n");
84 }
85 
bcm63xx_wdt_pet(void)86 static void bcm63xx_wdt_pet(void)
87 {
88 	atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
89 }
90 
bcm63xx_wdt_start(void)91 static void bcm63xx_wdt_start(void)
92 {
93 	bcm63xx_wdt_pet();
94 	bcm63xx_timer_tick(0);
95 }
96 
bcm63xx_wdt_pause(void)97 static void bcm63xx_wdt_pause(void)
98 {
99 	del_timer_sync(&bcm63xx_wdt_device.timer);
100 	bcm63xx_wdt_hw_stop();
101 }
102 
bcm63xx_wdt_settimeout(int new_time)103 static int bcm63xx_wdt_settimeout(int new_time)
104 {
105 	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
106 		return -EINVAL;
107 
108 	wdt_time = new_time;
109 
110 	return 0;
111 }
112 
bcm63xx_wdt_open(struct inode * inode,struct file * file)113 static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
114 {
115 	if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
116 		return -EBUSY;
117 
118 	bcm63xx_wdt_start();
119 	return stream_open(inode, file);
120 }
121 
bcm63xx_wdt_release(struct inode * inode,struct file * file)122 static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
123 {
124 	if (expect_close == 42)
125 		bcm63xx_wdt_pause();
126 	else {
127 		pr_crit("Unexpected close, not stopping watchdog!\n");
128 		bcm63xx_wdt_start();
129 	}
130 	clear_bit(0, &bcm63xx_wdt_device.inuse);
131 	expect_close = 0;
132 	return 0;
133 }
134 
bcm63xx_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)135 static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
136 				size_t len, loff_t *ppos)
137 {
138 	if (len) {
139 		if (!nowayout) {
140 			size_t i;
141 
142 			/* In case it was set long ago */
143 			expect_close = 0;
144 
145 			for (i = 0; i != len; i++) {
146 				char c;
147 				if (get_user(c, data + i))
148 					return -EFAULT;
149 				if (c == 'V')
150 					expect_close = 42;
151 			}
152 		}
153 		bcm63xx_wdt_pet();
154 	}
155 	return len;
156 }
157 
158 static struct watchdog_info bcm63xx_wdt_info = {
159 	.identity       = PFX,
160 	.options        = WDIOF_SETTIMEOUT |
161 				WDIOF_KEEPALIVEPING |
162 				WDIOF_MAGICCLOSE,
163 };
164 
165 
bcm63xx_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)166 static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
167 				unsigned long arg)
168 {
169 	void __user *argp = (void __user *)arg;
170 	int __user *p = argp;
171 	int new_value, retval = -EINVAL;
172 
173 	switch (cmd) {
174 	case WDIOC_GETSUPPORT:
175 		return copy_to_user(argp, &bcm63xx_wdt_info,
176 			sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
177 
178 	case WDIOC_GETSTATUS:
179 	case WDIOC_GETBOOTSTATUS:
180 		return put_user(0, p);
181 
182 	case WDIOC_SETOPTIONS:
183 		if (get_user(new_value, p))
184 			return -EFAULT;
185 
186 		if (new_value & WDIOS_DISABLECARD) {
187 			bcm63xx_wdt_pause();
188 			retval = 0;
189 		}
190 		if (new_value & WDIOS_ENABLECARD) {
191 			bcm63xx_wdt_start();
192 			retval = 0;
193 		}
194 
195 		return retval;
196 
197 	case WDIOC_KEEPALIVE:
198 		bcm63xx_wdt_pet();
199 		return 0;
200 
201 	case WDIOC_SETTIMEOUT:
202 		if (get_user(new_value, p))
203 			return -EFAULT;
204 
205 		if (bcm63xx_wdt_settimeout(new_value))
206 			return -EINVAL;
207 
208 		bcm63xx_wdt_pet();
209 
210 	case WDIOC_GETTIMEOUT:
211 		return put_user(wdt_time, p);
212 
213 	default:
214 		return -ENOTTY;
215 
216 	}
217 }
218 
219 static const struct file_operations bcm63xx_wdt_fops = {
220 	.owner		= THIS_MODULE,
221 	.llseek		= no_llseek,
222 	.write		= bcm63xx_wdt_write,
223 	.unlocked_ioctl	= bcm63xx_wdt_ioctl,
224 	.open		= bcm63xx_wdt_open,
225 	.release	= bcm63xx_wdt_release,
226 };
227 
228 static struct miscdevice bcm63xx_wdt_miscdev = {
229 	.minor	= WATCHDOG_MINOR,
230 	.name	= "watchdog",
231 	.fops	= &bcm63xx_wdt_fops,
232 };
233 
234 
bcm63xx_wdt_probe(struct platform_device * pdev)235 static int bcm63xx_wdt_probe(struct platform_device *pdev)
236 {
237 	int ret;
238 	struct resource *r;
239 
240 	timer_setup(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0);
241 
242 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
243 	if (!r) {
244 		dev_err(&pdev->dev, "failed to get resources\n");
245 		return -ENODEV;
246 	}
247 
248 	bcm63xx_wdt_device.regs = devm_ioremap_nocache(&pdev->dev, r->start,
249 							resource_size(r));
250 	if (!bcm63xx_wdt_device.regs) {
251 		dev_err(&pdev->dev, "failed to remap I/O resources\n");
252 		return -ENXIO;
253 	}
254 
255 	ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
256 	if (ret < 0) {
257 		dev_err(&pdev->dev, "failed to register wdt timer isr\n");
258 		return ret;
259 	}
260 
261 	if (bcm63xx_wdt_settimeout(wdt_time)) {
262 		bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
263 		dev_info(&pdev->dev,
264 			": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
265 			wdt_time);
266 	}
267 
268 	ret = misc_register(&bcm63xx_wdt_miscdev);
269 	if (ret < 0) {
270 		dev_err(&pdev->dev, "failed to register watchdog device\n");
271 		goto unregister_timer;
272 	}
273 
274 	dev_info(&pdev->dev, " started, timer margin: %d sec\n",
275 						WDT_DEFAULT_TIME);
276 
277 	return 0;
278 
279 unregister_timer:
280 	bcm63xx_timer_unregister(TIMER_WDT_ID);
281 	return ret;
282 }
283 
bcm63xx_wdt_remove(struct platform_device * pdev)284 static int bcm63xx_wdt_remove(struct platform_device *pdev)
285 {
286 	if (!nowayout)
287 		bcm63xx_wdt_pause();
288 
289 	misc_deregister(&bcm63xx_wdt_miscdev);
290 	bcm63xx_timer_unregister(TIMER_WDT_ID);
291 	return 0;
292 }
293 
bcm63xx_wdt_shutdown(struct platform_device * pdev)294 static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
295 {
296 	bcm63xx_wdt_pause();
297 }
298 
299 static struct platform_driver bcm63xx_wdt_driver = {
300 	.probe	= bcm63xx_wdt_probe,
301 	.remove = bcm63xx_wdt_remove,
302 	.shutdown = bcm63xx_wdt_shutdown,
303 	.driver = {
304 		.name = "bcm63xx-wdt",
305 	}
306 };
307 
308 module_platform_driver(bcm63xx_wdt_driver);
309 
310 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
311 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
312 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
313 MODULE_LICENSE("GPL");
314 MODULE_ALIAS("platform:bcm63xx-wdt");
315