1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * RDC321x watchdog driver
4  *
5  * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
6  *
7  * This driver is highly inspired from the cpu5_wdt driver
8  */
9 
10 #include <linux/module.h>
11 #include <linux/moduleparam.h>
12 #include <linux/types.h>
13 #include <linux/errno.h>
14 #include <linux/miscdevice.h>
15 #include <linux/fs.h>
16 #include <linux/ioport.h>
17 #include <linux/timer.h>
18 #include <linux/completion.h>
19 #include <linux/jiffies.h>
20 #include <linux/platform_device.h>
21 #include <linux/watchdog.h>
22 #include <linux/io.h>
23 #include <linux/uaccess.h>
24 #include <linux/mfd/rdc321x.h>
25 
26 #define RDC_WDT_MASK	0x80000000 /* Mask */
27 #define RDC_WDT_EN	0x00800000 /* Enable bit */
28 #define RDC_WDT_WTI	0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
29 #define RDC_WDT_RST	0x00100000 /* Reset bit */
30 #define RDC_WDT_WIF	0x00040000 /* WDT IRQ Flag */
31 #define RDC_WDT_IRT	0x00000100 /* IRQ Routing table */
32 #define RDC_WDT_CNT	0x00000001 /* WDT count */
33 
34 #define RDC_CLS_TMR	0x80003844 /* Clear timer */
35 
36 #define RDC_WDT_INTERVAL	(HZ/10+1)
37 
38 static int ticks = 1000;
39 
40 /* some device data */
41 
42 static struct {
43 	struct completion stop;
44 	int running;
45 	struct timer_list timer;
46 	int queue;
47 	int default_ticks;
48 	unsigned long inuse;
49 	spinlock_t lock;
50 	struct pci_dev *sb_pdev;
51 	int base_reg;
52 } rdc321x_wdt_device;
53 
54 /* generic helper functions */
55 
56 static void rdc321x_wdt_trigger(struct timer_list *unused)
57 {
58 	unsigned long flags;
59 	u32 val;
60 
61 	if (rdc321x_wdt_device.running)
62 		ticks--;
63 
64 	/* keep watchdog alive */
65 	spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
66 	pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
67 					rdc321x_wdt_device.base_reg, &val);
68 	val |= RDC_WDT_EN;
69 	pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
70 					rdc321x_wdt_device.base_reg, val);
71 	spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
72 
73 	/* requeue?? */
74 	if (rdc321x_wdt_device.queue && ticks)
75 		mod_timer(&rdc321x_wdt_device.timer,
76 				jiffies + RDC_WDT_INTERVAL);
77 	else {
78 		/* ticks doesn't matter anyway */
79 		complete(&rdc321x_wdt_device.stop);
80 	}
81 
82 }
83 
84 static void rdc321x_wdt_reset(void)
85 {
86 	ticks = rdc321x_wdt_device.default_ticks;
87 }
88 
89 static void rdc321x_wdt_start(void)
90 {
91 	unsigned long flags;
92 
93 	if (!rdc321x_wdt_device.queue) {
94 		rdc321x_wdt_device.queue = 1;
95 
96 		/* Clear the timer */
97 		spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
98 		pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
99 				rdc321x_wdt_device.base_reg, RDC_CLS_TMR);
100 
101 		/* Enable watchdog and set the timeout to 81.92 us */
102 		pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
103 					rdc321x_wdt_device.base_reg,
104 					RDC_WDT_EN | RDC_WDT_CNT);
105 		spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
106 
107 		mod_timer(&rdc321x_wdt_device.timer,
108 				jiffies + RDC_WDT_INTERVAL);
109 	}
110 
111 	/* if process dies, counter is not decremented */
112 	rdc321x_wdt_device.running++;
113 }
114 
115 static int rdc321x_wdt_stop(void)
116 {
117 	if (rdc321x_wdt_device.running)
118 		rdc321x_wdt_device.running = 0;
119 
120 	ticks = rdc321x_wdt_device.default_ticks;
121 
122 	return -EIO;
123 }
124 
125 /* filesystem operations */
126 static int rdc321x_wdt_open(struct inode *inode, struct file *file)
127 {
128 	if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
129 		return -EBUSY;
130 
131 	return stream_open(inode, file);
132 }
133 
134 static int rdc321x_wdt_release(struct inode *inode, struct file *file)
135 {
136 	clear_bit(0, &rdc321x_wdt_device.inuse);
137 	return 0;
138 }
139 
140 static long rdc321x_wdt_ioctl(struct file *file, unsigned int cmd,
141 				unsigned long arg)
142 {
143 	void __user *argp = (void __user *)arg;
144 	u32 value;
145 	static const struct watchdog_info ident = {
146 		.options = WDIOF_CARDRESET,
147 		.identity = "RDC321x WDT",
148 	};
149 	unsigned long flags;
150 
151 	switch (cmd) {
152 	case WDIOC_KEEPALIVE:
153 		rdc321x_wdt_reset();
154 		break;
155 	case WDIOC_GETSTATUS:
156 		/* Read the value from the DATA register */
157 		spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
158 		pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
159 					rdc321x_wdt_device.base_reg, &value);
160 		spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
161 		if (copy_to_user(argp, &value, sizeof(u32)))
162 			return -EFAULT;
163 		break;
164 	case WDIOC_GETSUPPORT:
165 		if (copy_to_user(argp, &ident, sizeof(ident)))
166 			return -EFAULT;
167 		break;
168 	case WDIOC_SETOPTIONS:
169 		if (copy_from_user(&value, argp, sizeof(int)))
170 			return -EFAULT;
171 		switch (value) {
172 		case WDIOS_ENABLECARD:
173 			rdc321x_wdt_start();
174 			break;
175 		case WDIOS_DISABLECARD:
176 			return rdc321x_wdt_stop();
177 		default:
178 			return -EINVAL;
179 		}
180 		break;
181 	default:
182 		return -ENOTTY;
183 	}
184 	return 0;
185 }
186 
187 static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
188 				size_t count, loff_t *ppos)
189 {
190 	if (!count)
191 		return -EIO;
192 
193 	rdc321x_wdt_reset();
194 
195 	return count;
196 }
197 
198 static const struct file_operations rdc321x_wdt_fops = {
199 	.owner		= THIS_MODULE,
200 	.llseek		= no_llseek,
201 	.unlocked_ioctl	= rdc321x_wdt_ioctl,
202 	.open		= rdc321x_wdt_open,
203 	.write		= rdc321x_wdt_write,
204 	.release	= rdc321x_wdt_release,
205 };
206 
207 static struct miscdevice rdc321x_wdt_misc = {
208 	.minor	= WATCHDOG_MINOR,
209 	.name	= "watchdog",
210 	.fops	= &rdc321x_wdt_fops,
211 };
212 
213 static int rdc321x_wdt_probe(struct platform_device *pdev)
214 {
215 	int err;
216 	struct resource *r;
217 	struct rdc321x_wdt_pdata *pdata;
218 
219 	pdata = dev_get_platdata(&pdev->dev);
220 	if (!pdata) {
221 		dev_err(&pdev->dev, "no platform data supplied\n");
222 		return -ENODEV;
223 	}
224 
225 	r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");
226 	if (!r) {
227 		dev_err(&pdev->dev, "failed to get wdt-reg resource\n");
228 		return -ENODEV;
229 	}
230 
231 	rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
232 	rdc321x_wdt_device.base_reg = r->start;
233 
234 	err = misc_register(&rdc321x_wdt_misc);
235 	if (err < 0) {
236 		dev_err(&pdev->dev, "misc_register failed\n");
237 		return err;
238 	}
239 
240 	spin_lock_init(&rdc321x_wdt_device.lock);
241 
242 	/* Reset the watchdog */
243 	pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
244 				rdc321x_wdt_device.base_reg, RDC_WDT_RST);
245 
246 	init_completion(&rdc321x_wdt_device.stop);
247 	rdc321x_wdt_device.queue = 0;
248 
249 	clear_bit(0, &rdc321x_wdt_device.inuse);
250 
251 	timer_setup(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
252 
253 	rdc321x_wdt_device.default_ticks = ticks;
254 
255 	dev_info(&pdev->dev, "watchdog init success\n");
256 
257 	return 0;
258 }
259 
260 static int rdc321x_wdt_remove(struct platform_device *pdev)
261 {
262 	if (rdc321x_wdt_device.queue) {
263 		rdc321x_wdt_device.queue = 0;
264 		wait_for_completion(&rdc321x_wdt_device.stop);
265 	}
266 
267 	misc_deregister(&rdc321x_wdt_misc);
268 
269 	return 0;
270 }
271 
272 static struct platform_driver rdc321x_wdt_driver = {
273 	.probe = rdc321x_wdt_probe,
274 	.remove = rdc321x_wdt_remove,
275 	.driver = {
276 		.name = "rdc321x-wdt",
277 	},
278 };
279 
280 module_platform_driver(rdc321x_wdt_driver);
281 
282 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
283 MODULE_DESCRIPTION("RDC321x watchdog driver");
284 MODULE_LICENSE("GPL");
285