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1/*
2 * PIKA FPGA based Watchdog Timer
3 *
4 * Copyright (c) 2008 PIKA Technologies
5 * Sean MacLennan <smaclennan@pikatech.com>
6 */
7
8#include <linux/init.h>
9#include <linux/errno.h>
10#include <linux/module.h>
11#include <linux/moduleparam.h>
12#include <linux/types.h>
13#include <linux/kernel.h>
14#include <linux/fs.h>
15#include <linux/miscdevice.h>
16#include <linux/watchdog.h>
17#include <linux/reboot.h>
18#include <linux/jiffies.h>
19#include <linux/timer.h>
20#include <linux/bitops.h>
21#include <linux/uaccess.h>
22#include <linux/io.h>
23#include <linux/of_platform.h>
24
25#define DRV_NAME "PIKA-WDT"
26#define PFX DRV_NAME ": "
27
28/* Hardware timeout in seconds */
29#define WDT_HW_TIMEOUT 2
30
31/* Timer heartbeat (500ms) */
32#define WDT_TIMEOUT (HZ/2)
33
34/* User land timeout */
35#define WDT_HEARTBEAT 15
36static int heartbeat = WDT_HEARTBEAT;
37module_param(heartbeat, int, 0);
38MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
39 "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
40
41static int nowayout = WATCHDOG_NOWAYOUT;
42module_param(nowayout, int, 0);
43MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
44 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
45
46static struct {
47 void __iomem *fpga;
48 unsigned long next_heartbeat; /* the next_heartbeat for the timer */
49 unsigned long open;
50 char expect_close;
51 int bootstatus;
52 struct timer_list timer; /* The timer that pings the watchdog */
53} pikawdt_private;
54
55static struct watchdog_info ident = {
56 .identity = DRV_NAME,
57 .options = WDIOF_CARDRESET |
58 WDIOF_SETTIMEOUT |
59 WDIOF_KEEPALIVEPING |
60 WDIOF_MAGICCLOSE,
61};
62
63/*
64 * Reload the watchdog timer. (ie, pat the watchdog)
65 */
66static inline void pikawdt_reset(void)
67{
68 /* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
69 * Bit 7, WTCHDG_EN: When set to 1, the watchdog timer is enabled.
70 * Once enabled, it cannot be disabled. The watchdog can be
71 * kicked by performing any write access to the reset
72 * control register (this register).
73 * Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
74 * seconds. Valid ranges are 1 to 15 seconds. The value can
75 * be modified dynamically.
76 */
77 unsigned reset = in_be32(pikawdt_private.fpga + 0x14);
78 /* enable with max timeout - 15 seconds */
79 reset |= (1 << 7) + (WDT_HW_TIMEOUT << 8);
80 out_be32(pikawdt_private.fpga + 0x14, reset);
81}
82
83/*
84 * Timer tick
85 */
86static void pikawdt_ping(unsigned long data)
87{
88 if (time_before(jiffies, pikawdt_private.next_heartbeat) ||
89 (!nowayout && !pikawdt_private.open)) {
90 pikawdt_reset();
91 mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
92 } else
93 printk(KERN_CRIT PFX "I will reset your machine !\n");
94}
95
96
97static void pikawdt_keepalive(void)
98{
99 pikawdt_private.next_heartbeat = jiffies + heartbeat * HZ;
100}
101
102static void pikawdt_start(void)
103{
104 pikawdt_keepalive();
105 mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
106}
107
108/*
109 * Watchdog device is opened, and watchdog starts running.
110 */
111static int pikawdt_open(struct inode *inode, struct file *file)
112{
113 /* /dev/watchdog can only be opened once */
114 if (test_and_set_bit(0, &pikawdt_private.open))
115 return -EBUSY;
116
117 pikawdt_start();
118
119 return nonseekable_open(inode, file);
120}
121
122/*
123 * Close the watchdog device.
124 */
125static int pikawdt_release(struct inode *inode, struct file *file)
126{
127 /* stop internal ping */
128 if (!pikawdt_private.expect_close)
129 del_timer(&pikawdt_private.timer);
130
131 clear_bit(0, &pikawdt_private.open);
132 pikawdt_private.expect_close = 0;
133 return 0;
134}
135
136/*
137 * Pat the watchdog whenever device is written to.
138 */
139static ssize_t pikawdt_write(struct file *file, const char __user *data,
140 size_t len, loff_t *ppos)
141{
142 if (!len)
143 return 0;
144
145 /* Scan for magic character */
146 if (!nowayout) {
147 size_t i;
148
149 pikawdt_private.expect_close = 0;
150
151 for (i = 0; i < len; i++) {
152 char c;
153 if (get_user(c, data + i))
154 return -EFAULT;
155 if (c == 'V') {
156 pikawdt_private.expect_close = 42;
157 break;
158 }
159 }
160 }
161
162 pikawdt_keepalive();
163
164 return len;
165}
166
167/*
168 * Handle commands from user-space.
169 */
170static long pikawdt_ioctl(struct file *file,
171 unsigned int cmd, unsigned long arg)
172{
173 void __user *argp = (void __user *)arg;
174 int __user *p = argp;
175 int new_value;
176
177 switch (cmd) {
178 case WDIOC_GETSUPPORT:
179 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
180
181 case WDIOC_GETSTATUS:
182 return put_user(0, p);
183
184 case WDIOC_GETBOOTSTATUS:
185 return put_user(pikawdt_private.bootstatus, p);
186
187 case WDIOC_KEEPALIVE:
188 pikawdt_keepalive();
189 return 0;
190
191 case WDIOC_SETTIMEOUT:
192 if (get_user(new_value, p))
193 return -EFAULT;
194
195 heartbeat = new_value;
196 pikawdt_keepalive();
197
198 return put_user(new_value, p); /* return current value */
199
200 case WDIOC_GETTIMEOUT:
201 return put_user(heartbeat, p);
202 }
203 return -ENOTTY;
204}
205
206
207static const struct file_operations pikawdt_fops = {
208 .owner = THIS_MODULE,
209 .llseek = no_llseek,
210 .open = pikawdt_open,
211 .release = pikawdt_release,
212 .write = pikawdt_write,
213 .unlocked_ioctl = pikawdt_ioctl,
214};
215
216static struct miscdevice pikawdt_miscdev = {
217 .minor = WATCHDOG_MINOR,
218 .name = "watchdog",
219 .fops = &pikawdt_fops,
220};
221
222static int __init pikawdt_init(void)
223{
224 struct device_node *np;
225 void __iomem *fpga;
226 static u32 post1;
227 int ret;
228
229 np = of_find_compatible_node(NULL, NULL, "pika,fpga");
230 if (np == NULL) {
231 printk(KERN_ERR PFX "Unable to find fpga.\n");
232 return -ENOENT;
233 }
234
235 pikawdt_private.fpga = of_iomap(np, 0);
236 of_node_put(np);
237 if (pikawdt_private.fpga == NULL) {
238 printk(KERN_ERR PFX "Unable to map fpga.\n");
239 return -ENOMEM;
240 }
241
242 ident.firmware_version = in_be32(pikawdt_private.fpga + 0x1c) & 0xffff;
243
244 /* POST information is in the sd area. */
245 np = of_find_compatible_node(NULL, NULL, "pika,fpga-sd");
246 if (np == NULL) {
247 printk(KERN_ERR PFX "Unable to find fpga-sd.\n");
248 ret = -ENOENT;
249 goto out;
250 }
251
252 fpga = of_iomap(np, 0);
253 of_node_put(np);
254 if (fpga == NULL) {
255 printk(KERN_ERR PFX "Unable to map fpga-sd.\n");
256 ret = -ENOMEM;
257 goto out;
258 }
259
260 /* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
261 * Bit 31, WDOG: Set to 1 when the last reset was caused by a watchdog
262 * timeout.
263 */
264 post1 = in_be32(fpga + 0x40);
265 if (post1 & 0x80000000)
266 pikawdt_private.bootstatus = WDIOF_CARDRESET;
267
268 iounmap(fpga);
269
270 setup_timer(&pikawdt_private.timer, pikawdt_ping, 0);
271
272 ret = misc_register(&pikawdt_miscdev);
273 if (ret) {
274 printk(KERN_ERR PFX "Unable to register miscdev.\n");
275 goto out;
276 }
277
278 printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
279 heartbeat, nowayout);
280 return 0;
281
282out:
283 iounmap(pikawdt_private.fpga);
284 return ret;
285}
286
287static void __exit pikawdt_exit(void)
288{
289 misc_deregister(&pikawdt_miscdev);
290
291 iounmap(pikawdt_private.fpga);
292}
293
294module_init(pikawdt_init);
295module_exit(pikawdt_exit);
296
297MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
298MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
299MODULE_LICENSE("GPL");
300MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
301
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PIKA FPGA based Watchdog Timer
4 *
5 * Copyright (c) 2008 PIKA Technologies
6 * Sean MacLennan <smaclennan@pikatech.com>
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/init.h>
12#include <linux/errno.h>
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/fs.h>
18#include <linux/miscdevice.h>
19#include <linux/watchdog.h>
20#include <linux/reboot.h>
21#include <linux/jiffies.h>
22#include <linux/timer.h>
23#include <linux/bitops.h>
24#include <linux/uaccess.h>
25#include <linux/io.h>
26#include <linux/of_address.h>
27#include <linux/of_platform.h>
28
29#define DRV_NAME "PIKA-WDT"
30
31/* Hardware timeout in seconds */
32#define WDT_HW_TIMEOUT 2
33
34/* Timer heartbeat (500ms) */
35#define WDT_TIMEOUT (HZ/2)
36
37/* User land timeout */
38#define WDT_HEARTBEAT 15
39static int heartbeat = WDT_HEARTBEAT;
40module_param(heartbeat, int, 0);
41MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
42 "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
43
44static bool nowayout = WATCHDOG_NOWAYOUT;
45module_param(nowayout, bool, 0);
46MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
47 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
48
49static struct {
50 void __iomem *fpga;
51 unsigned long next_heartbeat; /* the next_heartbeat for the timer */
52 unsigned long open;
53 char expect_close;
54 int bootstatus;
55 struct timer_list timer; /* The timer that pings the watchdog */
56} pikawdt_private;
57
58static struct watchdog_info ident __ro_after_init = {
59 .identity = DRV_NAME,
60 .options = WDIOF_CARDRESET |
61 WDIOF_SETTIMEOUT |
62 WDIOF_KEEPALIVEPING |
63 WDIOF_MAGICCLOSE,
64};
65
66/*
67 * Reload the watchdog timer. (ie, pat the watchdog)
68 */
69static inline void pikawdt_reset(void)
70{
71 /* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
72 * Bit 7, WTCHDG_EN: When set to 1, the watchdog timer is enabled.
73 * Once enabled, it cannot be disabled. The watchdog can be
74 * kicked by performing any write access to the reset
75 * control register (this register).
76 * Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
77 * seconds. Valid ranges are 1 to 15 seconds. The value can
78 * be modified dynamically.
79 */
80 unsigned reset = in_be32(pikawdt_private.fpga + 0x14);
81 /* enable with max timeout - 15 seconds */
82 reset |= (1 << 7) + (WDT_HW_TIMEOUT << 8);
83 out_be32(pikawdt_private.fpga + 0x14, reset);
84}
85
86/*
87 * Timer tick
88 */
89static void pikawdt_ping(struct timer_list *unused)
90{
91 if (time_before(jiffies, pikawdt_private.next_heartbeat) ||
92 (!nowayout && !pikawdt_private.open)) {
93 pikawdt_reset();
94 mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
95 } else
96 pr_crit("I will reset your machine !\n");
97}
98
99
100static void pikawdt_keepalive(void)
101{
102 pikawdt_private.next_heartbeat = jiffies + heartbeat * HZ;
103}
104
105static void pikawdt_start(void)
106{
107 pikawdt_keepalive();
108 mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
109}
110
111/*
112 * Watchdog device is opened, and watchdog starts running.
113 */
114static int pikawdt_open(struct inode *inode, struct file *file)
115{
116 /* /dev/watchdog can only be opened once */
117 if (test_and_set_bit(0, &pikawdt_private.open))
118 return -EBUSY;
119
120 pikawdt_start();
121
122 return stream_open(inode, file);
123}
124
125/*
126 * Close the watchdog device.
127 */
128static int pikawdt_release(struct inode *inode, struct file *file)
129{
130 /* stop internal ping */
131 if (!pikawdt_private.expect_close)
132 del_timer(&pikawdt_private.timer);
133
134 clear_bit(0, &pikawdt_private.open);
135 pikawdt_private.expect_close = 0;
136 return 0;
137}
138
139/*
140 * Pat the watchdog whenever device is written to.
141 */
142static ssize_t pikawdt_write(struct file *file, const char __user *data,
143 size_t len, loff_t *ppos)
144{
145 if (!len)
146 return 0;
147
148 /* Scan for magic character */
149 if (!nowayout) {
150 size_t i;
151
152 pikawdt_private.expect_close = 0;
153
154 for (i = 0; i < len; i++) {
155 char c;
156 if (get_user(c, data + i))
157 return -EFAULT;
158 if (c == 'V') {
159 pikawdt_private.expect_close = 42;
160 break;
161 }
162 }
163 }
164
165 pikawdt_keepalive();
166
167 return len;
168}
169
170/*
171 * Handle commands from user-space.
172 */
173static long pikawdt_ioctl(struct file *file,
174 unsigned int cmd, unsigned long arg)
175{
176 void __user *argp = (void __user *)arg;
177 int __user *p = argp;
178 int new_value;
179
180 switch (cmd) {
181 case WDIOC_GETSUPPORT:
182 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
183
184 case WDIOC_GETSTATUS:
185 return put_user(0, p);
186
187 case WDIOC_GETBOOTSTATUS:
188 return put_user(pikawdt_private.bootstatus, p);
189
190 case WDIOC_KEEPALIVE:
191 pikawdt_keepalive();
192 return 0;
193
194 case WDIOC_SETTIMEOUT:
195 if (get_user(new_value, p))
196 return -EFAULT;
197
198 heartbeat = new_value;
199 pikawdt_keepalive();
200
201 return put_user(new_value, p); /* return current value */
202
203 case WDIOC_GETTIMEOUT:
204 return put_user(heartbeat, p);
205 }
206 return -ENOTTY;
207}
208
209
210static const struct file_operations pikawdt_fops = {
211 .owner = THIS_MODULE,
212 .llseek = no_llseek,
213 .open = pikawdt_open,
214 .release = pikawdt_release,
215 .write = pikawdt_write,
216 .unlocked_ioctl = pikawdt_ioctl,
217 .compat_ioctl = compat_ptr_ioctl,
218};
219
220static struct miscdevice pikawdt_miscdev = {
221 .minor = WATCHDOG_MINOR,
222 .name = "watchdog",
223 .fops = &pikawdt_fops,
224};
225
226static int __init pikawdt_init(void)
227{
228 struct device_node *np;
229 void __iomem *fpga;
230 u32 post1;
231 int ret;
232
233 np = of_find_compatible_node(NULL, NULL, "pika,fpga");
234 if (np == NULL) {
235 pr_err("Unable to find fpga\n");
236 return -ENOENT;
237 }
238
239 pikawdt_private.fpga = of_iomap(np, 0);
240 of_node_put(np);
241 if (pikawdt_private.fpga == NULL) {
242 pr_err("Unable to map fpga\n");
243 return -ENOMEM;
244 }
245
246 ident.firmware_version = in_be32(pikawdt_private.fpga + 0x1c) & 0xffff;
247
248 /* POST information is in the sd area. */
249 np = of_find_compatible_node(NULL, NULL, "pika,fpga-sd");
250 if (np == NULL) {
251 pr_err("Unable to find fpga-sd\n");
252 ret = -ENOENT;
253 goto out;
254 }
255
256 fpga = of_iomap(np, 0);
257 of_node_put(np);
258 if (fpga == NULL) {
259 pr_err("Unable to map fpga-sd\n");
260 ret = -ENOMEM;
261 goto out;
262 }
263
264 /* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
265 * Bit 31, WDOG: Set to 1 when the last reset was caused by a watchdog
266 * timeout.
267 */
268 post1 = in_be32(fpga + 0x40);
269 if (post1 & 0x80000000)
270 pikawdt_private.bootstatus = WDIOF_CARDRESET;
271
272 iounmap(fpga);
273
274 timer_setup(&pikawdt_private.timer, pikawdt_ping, 0);
275
276 ret = misc_register(&pikawdt_miscdev);
277 if (ret) {
278 pr_err("Unable to register miscdev\n");
279 goto out;
280 }
281
282 pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
283 heartbeat, nowayout);
284 return 0;
285
286out:
287 iounmap(pikawdt_private.fpga);
288 return ret;
289}
290
291static void __exit pikawdt_exit(void)
292{
293 misc_deregister(&pikawdt_miscdev);
294
295 iounmap(pikawdt_private.fpga);
296}
297
298module_init(pikawdt_init);
299module_exit(pikawdt_exit);
300
301MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
302MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
303MODULE_LICENSE("GPL");