2 * PIKA FPGA based Watchdog Timer
4 * Copyright (c) 2008 PIKA Technologies
5 * Sean MacLennan <smaclennan@pikatech.com>
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 #include <linux/init.h>
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
17 #include <linux/miscdevice.h>
18 #include <linux/watchdog.h>
19 #include <linux/reboot.h>
20 #include <linux/jiffies.h>
21 #include <linux/timer.h>
22 #include <linux/bitops.h>
23 #include <linux/uaccess.h>
25 #include <linux/of_address.h>
26 #include <linux/of_platform.h>
28 #define DRV_NAME "PIKA-WDT"
30 /* Hardware timeout in seconds */
31 #define WDT_HW_TIMEOUT 2
33 /* Timer heartbeat (500ms) */
34 #define WDT_TIMEOUT (HZ/2)
36 /* User land timeout */
37 #define WDT_HEARTBEAT 15
38 static int heartbeat
= WDT_HEARTBEAT
;
39 module_param(heartbeat
, int, 0);
40 MODULE_PARM_DESC(heartbeat
, "Watchdog heartbeats in seconds. "
41 "(default = " __MODULE_STRING(WDT_HEARTBEAT
) ")");
43 static bool nowayout
= WATCHDOG_NOWAYOUT
;
44 module_param(nowayout
, bool, 0);
45 MODULE_PARM_DESC(nowayout
, "Watchdog cannot be stopped once started "
46 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
50 unsigned long next_heartbeat
; /* the next_heartbeat for the timer */
54 struct timer_list timer
; /* The timer that pings the watchdog */
57 static struct watchdog_info ident __ro_after_init
= {
59 .options
= WDIOF_CARDRESET
|
66 * Reload the watchdog timer. (ie, pat the watchdog)
68 static inline void pikawdt_reset(void)
70 /* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
71 * Bit 7, WTCHDG_EN: When set to 1, the watchdog timer is enabled.
72 * Once enabled, it cannot be disabled. The watchdog can be
73 * kicked by performing any write access to the reset
74 * control register (this register).
75 * Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
76 * seconds. Valid ranges are 1 to 15 seconds. The value can
77 * be modified dynamically.
79 unsigned reset
= in_be32(pikawdt_private
.fpga
+ 0x14);
80 /* enable with max timeout - 15 seconds */
81 reset
|= (1 << 7) + (WDT_HW_TIMEOUT
<< 8);
82 out_be32(pikawdt_private
.fpga
+ 0x14, reset
);
88 static void pikawdt_ping(struct timer_list
*unused
)
90 if (time_before(jiffies
, pikawdt_private
.next_heartbeat
) ||
91 (!nowayout
&& !pikawdt_private
.open
)) {
93 mod_timer(&pikawdt_private
.timer
, jiffies
+ WDT_TIMEOUT
);
95 pr_crit("I will reset your machine !\n");
99 static void pikawdt_keepalive(void)
101 pikawdt_private
.next_heartbeat
= jiffies
+ heartbeat
* HZ
;
104 static void pikawdt_start(void)
107 mod_timer(&pikawdt_private
.timer
, jiffies
+ WDT_TIMEOUT
);
111 * Watchdog device is opened, and watchdog starts running.
113 static int pikawdt_open(struct inode
*inode
, struct file
*file
)
115 /* /dev/watchdog can only be opened once */
116 if (test_and_set_bit(0, &pikawdt_private
.open
))
121 return nonseekable_open(inode
, file
);
125 * Close the watchdog device.
127 static int pikawdt_release(struct inode
*inode
, struct file
*file
)
129 /* stop internal ping */
130 if (!pikawdt_private
.expect_close
)
131 del_timer(&pikawdt_private
.timer
);
133 clear_bit(0, &pikawdt_private
.open
);
134 pikawdt_private
.expect_close
= 0;
139 * Pat the watchdog whenever device is written to.
141 static ssize_t
pikawdt_write(struct file
*file
, const char __user
*data
,
142 size_t len
, loff_t
*ppos
)
147 /* Scan for magic character */
151 pikawdt_private
.expect_close
= 0;
153 for (i
= 0; i
< len
; i
++) {
155 if (get_user(c
, data
+ i
))
158 pikawdt_private
.expect_close
= 42;
170 * Handle commands from user-space.
172 static long pikawdt_ioctl(struct file
*file
,
173 unsigned int cmd
, unsigned long arg
)
175 void __user
*argp
= (void __user
*)arg
;
176 int __user
*p
= argp
;
180 case WDIOC_GETSUPPORT
:
181 return copy_to_user(argp
, &ident
, sizeof(ident
)) ? -EFAULT
: 0;
183 case WDIOC_GETSTATUS
:
184 return put_user(0, p
);
186 case WDIOC_GETBOOTSTATUS
:
187 return put_user(pikawdt_private
.bootstatus
, p
);
189 case WDIOC_KEEPALIVE
:
193 case WDIOC_SETTIMEOUT
:
194 if (get_user(new_value
, p
))
197 heartbeat
= new_value
;
200 return put_user(new_value
, p
); /* return current value */
202 case WDIOC_GETTIMEOUT
:
203 return put_user(heartbeat
, p
);
209 static const struct file_operations pikawdt_fops
= {
210 .owner
= THIS_MODULE
,
212 .open
= pikawdt_open
,
213 .release
= pikawdt_release
,
214 .write
= pikawdt_write
,
215 .unlocked_ioctl
= pikawdt_ioctl
,
218 static struct miscdevice pikawdt_miscdev
= {
219 .minor
= WATCHDOG_MINOR
,
221 .fops
= &pikawdt_fops
,
224 static int __init
pikawdt_init(void)
226 struct device_node
*np
;
231 np
= of_find_compatible_node(NULL
, NULL
, "pika,fpga");
233 pr_err("Unable to find fpga\n");
237 pikawdt_private
.fpga
= of_iomap(np
, 0);
239 if (pikawdt_private
.fpga
== NULL
) {
240 pr_err("Unable to map fpga\n");
244 ident
.firmware_version
= in_be32(pikawdt_private
.fpga
+ 0x1c) & 0xffff;
246 /* POST information is in the sd area. */
247 np
= of_find_compatible_node(NULL
, NULL
, "pika,fpga-sd");
249 pr_err("Unable to find fpga-sd\n");
254 fpga
= of_iomap(np
, 0);
257 pr_err("Unable to map fpga-sd\n");
262 /* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
263 * Bit 31, WDOG: Set to 1 when the last reset was caused by a watchdog
266 post1
= in_be32(fpga
+ 0x40);
267 if (post1
& 0x80000000)
268 pikawdt_private
.bootstatus
= WDIOF_CARDRESET
;
272 timer_setup(&pikawdt_private
.timer
, pikawdt_ping
, 0);
274 ret
= misc_register(&pikawdt_miscdev
);
276 pr_err("Unable to register miscdev\n");
280 pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
281 heartbeat
, nowayout
);
285 iounmap(pikawdt_private
.fpga
);
289 static void __exit
pikawdt_exit(void)
291 misc_deregister(&pikawdt_miscdev
);
293 iounmap(pikawdt_private
.fpga
);
296 module_init(pikawdt_init
);
297 module_exit(pikawdt_exit
);
299 MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
300 MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
301 MODULE_LICENSE("GPL");