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Sean MacLennan618efba2008-09-23 20:26:26 -04001/*
2 * PIKA FPGA based Watchdog Timer
3 *
4 * Copyright (c) 2008 PIKA Technologies
5 * Sean MacLennan <smaclennan@pikatech.com>
6 */
7
Joe Perches27c766a2012-02-15 15:06:19 -08008#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
Sean MacLennan618efba2008-09-23 20:26:26 -040010#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>
16#include <linux/fs.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>
24#include <linux/io.h>
25#include <linux/of_platform.h>
26
27#define DRV_NAME "PIKA-WDT"
Sean MacLennan618efba2008-09-23 20:26:26 -040028
29/* Hardware timeout in seconds */
30#define WDT_HW_TIMEOUT 2
31
32/* Timer heartbeat (500ms) */
33#define WDT_TIMEOUT (HZ/2)
34
35/* User land timeout */
36#define WDT_HEARTBEAT 15
37static int heartbeat = WDT_HEARTBEAT;
38module_param(heartbeat, int, 0);
39MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
40 "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
41
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010042static bool nowayout = WATCHDOG_NOWAYOUT;
43module_param(nowayout, bool, 0);
Sean MacLennan618efba2008-09-23 20:26:26 -040044MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
45 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
46
47static struct {
48 void __iomem *fpga;
49 unsigned long next_heartbeat; /* the next_heartbeat for the timer */
50 unsigned long open;
51 char expect_close;
52 int bootstatus;
53 struct timer_list timer; /* The timer that pings the watchdog */
54} pikawdt_private;
55
Sean MacLennan35c79782010-03-08 19:46:41 -050056static struct watchdog_info ident = {
Sean MacLennan618efba2008-09-23 20:26:26 -040057 .identity = DRV_NAME,
58 .options = WDIOF_CARDRESET |
59 WDIOF_SETTIMEOUT |
60 WDIOF_KEEPALIVEPING |
61 WDIOF_MAGICCLOSE,
62};
63
64/*
65 * Reload the watchdog timer. (ie, pat the watchdog)
66 */
67static inline void pikawdt_reset(void)
68{
69 /* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
70 * Bit 7, WTCHDG_EN: When set to 1, the watchdog timer is enabled.
71 * Once enabled, it cannot be disabled. The watchdog can be
72 * kicked by performing any write access to the reset
73 * control register (this register).
74 * Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
75 * seconds. Valid ranges are 1 to 15 seconds. The value can
76 * be modified dynamically.
77 */
78 unsigned reset = in_be32(pikawdt_private.fpga + 0x14);
79 /* enable with max timeout - 15 seconds */
80 reset |= (1 << 7) + (WDT_HW_TIMEOUT << 8);
81 out_be32(pikawdt_private.fpga + 0x14, reset);
82}
83
84/*
85 * Timer tick
86 */
87static void pikawdt_ping(unsigned long data)
88{
89 if (time_before(jiffies, pikawdt_private.next_heartbeat) ||
90 (!nowayout && !pikawdt_private.open)) {
91 pikawdt_reset();
92 mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
93 } else
Joe Perches27c766a2012-02-15 15:06:19 -080094 pr_crit("I will reset your machine !\n");
Sean MacLennan618efba2008-09-23 20:26:26 -040095}
96
97
98static void pikawdt_keepalive(void)
99{
100 pikawdt_private.next_heartbeat = jiffies + heartbeat * HZ;
101}
102
103static void pikawdt_start(void)
104{
105 pikawdt_keepalive();
106 mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
107}
108
109/*
110 * Watchdog device is opened, and watchdog starts running.
111 */
112static int pikawdt_open(struct inode *inode, struct file *file)
113{
114 /* /dev/watchdog can only be opened once */
115 if (test_and_set_bit(0, &pikawdt_private.open))
116 return -EBUSY;
117
118 pikawdt_start();
119
120 return nonseekable_open(inode, file);
121}
122
123/*
124 * Close the watchdog device.
125 */
126static int pikawdt_release(struct inode *inode, struct file *file)
127{
128 /* stop internal ping */
129 if (!pikawdt_private.expect_close)
130 del_timer(&pikawdt_private.timer);
131
132 clear_bit(0, &pikawdt_private.open);
133 pikawdt_private.expect_close = 0;
134 return 0;
135}
136
137/*
138 * Pat the watchdog whenever device is written to.
139 */
140static ssize_t pikawdt_write(struct file *file, const char __user *data,
141 size_t len, loff_t *ppos)
142{
143 if (!len)
144 return 0;
145
146 /* Scan for magic character */
147 if (!nowayout) {
148 size_t i;
149
150 pikawdt_private.expect_close = 0;
151
152 for (i = 0; i < len; i++) {
153 char c;
154 if (get_user(c, data + i))
155 return -EFAULT;
156 if (c == 'V') {
157 pikawdt_private.expect_close = 42;
158 break;
159 }
160 }
161 }
162
163 pikawdt_keepalive();
164
165 return len;
166}
167
168/*
169 * Handle commands from user-space.
170 */
171static long pikawdt_ioctl(struct file *file,
172 unsigned int cmd, unsigned long arg)
173{
174 void __user *argp = (void __user *)arg;
175 int __user *p = argp;
176 int new_value;
177
178 switch (cmd) {
179 case WDIOC_GETSUPPORT:
180 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
181
182 case WDIOC_GETSTATUS:
183 return put_user(0, p);
184
185 case WDIOC_GETBOOTSTATUS:
186 return put_user(pikawdt_private.bootstatus, p);
187
188 case WDIOC_KEEPALIVE:
189 pikawdt_keepalive();
190 return 0;
191
192 case WDIOC_SETTIMEOUT:
193 if (get_user(new_value, p))
194 return -EFAULT;
195
196 heartbeat = new_value;
197 pikawdt_keepalive();
198
199 return put_user(new_value, p); /* return current value */
200
201 case WDIOC_GETTIMEOUT:
202 return put_user(heartbeat, p);
203 }
204 return -ENOTTY;
205}
206
207
208static const struct file_operations pikawdt_fops = {
209 .owner = THIS_MODULE,
210 .llseek = no_llseek,
211 .open = pikawdt_open,
212 .release = pikawdt_release,
213 .write = pikawdt_write,
214 .unlocked_ioctl = pikawdt_ioctl,
215};
216
217static struct miscdevice pikawdt_miscdev = {
218 .minor = WATCHDOG_MINOR,
219 .name = "watchdog",
220 .fops = &pikawdt_fops,
221};
222
223static int __init pikawdt_init(void)
224{
225 struct device_node *np;
226 void __iomem *fpga;
227 static u32 post1;
228 int ret;
229
230 np = of_find_compatible_node(NULL, NULL, "pika,fpga");
231 if (np == NULL) {
Joe Perches27c766a2012-02-15 15:06:19 -0800232 pr_err("Unable to find fpga\n");
Sean MacLennan618efba2008-09-23 20:26:26 -0400233 return -ENOENT;
234 }
235
236 pikawdt_private.fpga = of_iomap(np, 0);
237 of_node_put(np);
238 if (pikawdt_private.fpga == NULL) {
Joe Perches27c766a2012-02-15 15:06:19 -0800239 pr_err("Unable to map fpga\n");
Sean MacLennan618efba2008-09-23 20:26:26 -0400240 return -ENOMEM;
241 }
242
243 ident.firmware_version = in_be32(pikawdt_private.fpga + 0x1c) & 0xffff;
244
245 /* POST information is in the sd area. */
246 np = of_find_compatible_node(NULL, NULL, "pika,fpga-sd");
247 if (np == NULL) {
Joe Perches27c766a2012-02-15 15:06:19 -0800248 pr_err("Unable to find fpga-sd\n");
Sean MacLennan618efba2008-09-23 20:26:26 -0400249 ret = -ENOENT;
250 goto out;
251 }
252
253 fpga = of_iomap(np, 0);
254 of_node_put(np);
255 if (fpga == NULL) {
Joe Perches27c766a2012-02-15 15:06:19 -0800256 pr_err("Unable to map fpga-sd\n");
Sean MacLennan618efba2008-09-23 20:26:26 -0400257 ret = -ENOMEM;
258 goto out;
259 }
260
261 /* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
262 * Bit 31, WDOG: Set to 1 when the last reset was caused by a watchdog
263 * timeout.
264 */
265 post1 = in_be32(fpga + 0x40);
266 if (post1 & 0x80000000)
267 pikawdt_private.bootstatus = WDIOF_CARDRESET;
268
269 iounmap(fpga);
270
271 setup_timer(&pikawdt_private.timer, pikawdt_ping, 0);
272
273 ret = misc_register(&pikawdt_miscdev);
274 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800275 pr_err("Unable to register miscdev\n");
Sean MacLennan618efba2008-09-23 20:26:26 -0400276 goto out;
277 }
278
Joe Perches27c766a2012-02-15 15:06:19 -0800279 pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
280 heartbeat, nowayout);
Sean MacLennan618efba2008-09-23 20:26:26 -0400281 return 0;
282
283out:
284 iounmap(pikawdt_private.fpga);
285 return ret;
286}
287
288static void __exit pikawdt_exit(void)
289{
290 misc_deregister(&pikawdt_miscdev);
291
292 iounmap(pikawdt_private.fpga);
293}
294
295module_init(pikawdt_init);
296module_exit(pikawdt_exit);
297
298MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
299MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
300MODULE_LICENSE("GPL");
301MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
302