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
rdc321x_wdt_trigger(struct timer_list * unused)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
rdc321x_wdt_reset(void)84 static void rdc321x_wdt_reset(void)
85 {
86 ticks = rdc321x_wdt_device.default_ticks;
87 }
88
rdc321x_wdt_start(void)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
rdc321x_wdt_stop(void)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 */
rdc321x_wdt_open(struct inode * inode,struct file * file)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
rdc321x_wdt_release(struct inode * inode,struct file * file)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
rdc321x_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)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
rdc321x_wdt_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)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 .unlocked_ioctl = rdc321x_wdt_ioctl,
201 .compat_ioctl = compat_ptr_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
rdc321x_wdt_probe(struct platform_device * pdev)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 rdc321x_wdt_device.queue = 0;
234 rdc321x_wdt_device.default_ticks = ticks;
235
236 err = misc_register(&rdc321x_wdt_misc);
237 if (err < 0) {
238 dev_err(&pdev->dev, "misc_register failed\n");
239 return err;
240 }
241
242 spin_lock_init(&rdc321x_wdt_device.lock);
243
244 /* Reset the watchdog */
245 pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
246 rdc321x_wdt_device.base_reg, RDC_WDT_RST);
247
248 init_completion(&rdc321x_wdt_device.stop);
249
250 clear_bit(0, &rdc321x_wdt_device.inuse);
251
252 timer_setup(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
253
254 dev_info(&pdev->dev, "watchdog init success\n");
255
256 return 0;
257 }
258
rdc321x_wdt_remove(struct platform_device * pdev)259 static void rdc321x_wdt_remove(struct platform_device *pdev)
260 {
261 if (rdc321x_wdt_device.queue) {
262 rdc321x_wdt_device.queue = 0;
263 wait_for_completion(&rdc321x_wdt_device.stop);
264 }
265
266 misc_deregister(&rdc321x_wdt_misc);
267 }
268
269 static struct platform_driver rdc321x_wdt_driver = {
270 .probe = rdc321x_wdt_probe,
271 .remove = rdc321x_wdt_remove,
272 .driver = {
273 .name = "rdc321x-wdt",
274 },
275 };
276
277 module_platform_driver(rdc321x_wdt_driver);
278
279 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
280 MODULE_DESCRIPTION("RDC321x watchdog driver");
281 MODULE_LICENSE("GPL");
282