Merge tag 'v5.15.57' into rpi-5.15.y
[platform/kernel/linux-rpi.git] / drivers / watchdog / rdc321x_wdt.c
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         .compat_ioctl   = compat_ptr_ioctl,
203         .open           = rdc321x_wdt_open,
204         .write          = rdc321x_wdt_write,
205         .release        = rdc321x_wdt_release,
206 };
207
208 static struct miscdevice rdc321x_wdt_misc = {
209         .minor  = WATCHDOG_MINOR,
210         .name   = "watchdog",
211         .fops   = &rdc321x_wdt_fops,
212 };
213
214 static int rdc321x_wdt_probe(struct platform_device *pdev)
215 {
216         int err;
217         struct resource *r;
218         struct rdc321x_wdt_pdata *pdata;
219
220         pdata = dev_get_platdata(&pdev->dev);
221         if (!pdata) {
222                 dev_err(&pdev->dev, "no platform data supplied\n");
223                 return -ENODEV;
224         }
225
226         r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");
227         if (!r) {
228                 dev_err(&pdev->dev, "failed to get wdt-reg resource\n");
229                 return -ENODEV;
230         }
231
232         rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
233         rdc321x_wdt_device.base_reg = r->start;
234         rdc321x_wdt_device.queue = 0;
235         rdc321x_wdt_device.default_ticks = ticks;
236
237         err = misc_register(&rdc321x_wdt_misc);
238         if (err < 0) {
239                 dev_err(&pdev->dev, "misc_register failed\n");
240                 return err;
241         }
242
243         spin_lock_init(&rdc321x_wdt_device.lock);
244
245         /* Reset the watchdog */
246         pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
247                                 rdc321x_wdt_device.base_reg, RDC_WDT_RST);
248
249         init_completion(&rdc321x_wdt_device.stop);
250
251         clear_bit(0, &rdc321x_wdt_device.inuse);
252
253         timer_setup(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
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");