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20#include <linux/fs.h>
21#include <linux/init.h>
22#include <linux/kernel.h>
23#include <linux/timer.h>
24#include <linux/miscdevice.h>
25#include <linux/of_platform.h>
26#include <linux/module.h>
27#include <linux/watchdog.h>
28#include <linux/io.h>
29#include <linux/uaccess.h>
30#include <sysdev/fsl_soc.h>
31
32struct mpc8xxx_wdt {
33 __be32 res0;
34 __be32 swcrr;
35#define SWCRR_SWTC 0xFFFF0000
36#define SWCRR_SWEN 0x00000004
37#define SWCRR_SWRI 0x00000002
38#define SWCRR_SWPR 0x00000001
39 __be32 swcnr;
40 u8 res1[2];
41 __be16 swsrr;
42 u8 res2[0xF0];
43};
44
45struct mpc8xxx_wdt_type {
46 int prescaler;
47 bool hw_enabled;
48};
49
50static struct mpc8xxx_wdt __iomem *wd_base;
51static int mpc8xxx_wdt_init_late(void);
52
53static u16 timeout = 0xffff;
54module_param(timeout, ushort, 0);
55MODULE_PARM_DESC(timeout,
56 "Watchdog timeout in ticks. (0<timeout<65536, default=65535");
57
58static int reset = 1;
59module_param(reset, bool, 0);
60MODULE_PARM_DESC(reset,
61 "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
62
63static int nowayout = WATCHDOG_NOWAYOUT;
64module_param(nowayout, int, 0);
65MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
66 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
67
68
69
70
71
72static int prescale = 1;
73static unsigned int timeout_sec;
74
75static unsigned long wdt_is_open;
76static DEFINE_SPINLOCK(wdt_spinlock);
77
78static void mpc8xxx_wdt_keepalive(void)
79{
80
81 spin_lock(&wdt_spinlock);
82 out_be16(&wd_base->swsrr, 0x556c);
83 out_be16(&wd_base->swsrr, 0xaa39);
84 spin_unlock(&wdt_spinlock);
85}
86
87static void mpc8xxx_wdt_timer_ping(unsigned long arg);
88static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, 0);
89
90static void mpc8xxx_wdt_timer_ping(unsigned long arg)
91{
92 mpc8xxx_wdt_keepalive();
93
94 mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2);
95}
96
97static void mpc8xxx_wdt_pr_warn(const char *msg)
98{
99 pr_crit("mpc8xxx_wdt: %s, expect the %s soon!\n", msg,
100 reset ? "reset" : "machine check exception");
101}
102
103static ssize_t mpc8xxx_wdt_write(struct file *file, const char __user *buf,
104 size_t count, loff_t *ppos)
105{
106 if (count)
107 mpc8xxx_wdt_keepalive();
108 return count;
109}
110
111static int mpc8xxx_wdt_open(struct inode *inode, struct file *file)
112{
113 u32 tmp = SWCRR_SWEN;
114 if (test_and_set_bit(0, &wdt_is_open))
115 return -EBUSY;
116
117
118 if (nowayout)
119 __module_get(THIS_MODULE);
120
121
122 if (prescale)
123 tmp |= SWCRR_SWPR;
124 if (reset)
125 tmp |= SWCRR_SWRI;
126
127 tmp |= timeout << 16;
128
129 out_be32(&wd_base->swcrr, tmp);
130
131 del_timer_sync(&wdt_timer);
132
133 return nonseekable_open(inode, file);
134}
135
136static int mpc8xxx_wdt_release(struct inode *inode, struct file *file)
137{
138 if (!nowayout)
139 mpc8xxx_wdt_timer_ping(0);
140 else
141 mpc8xxx_wdt_pr_warn("watchdog closed");
142 clear_bit(0, &wdt_is_open);
143 return 0;
144}
145
146static long mpc8xxx_wdt_ioctl(struct file *file, unsigned int cmd,
147 unsigned long arg)
148{
149 void __user *argp = (void __user *)arg;
150 int __user *p = argp;
151 static struct watchdog_info ident = {
152 .options = WDIOF_KEEPALIVEPING,
153 .firmware_version = 1,
154 .identity = "MPC8xxx",
155 };
156
157 switch (cmd) {
158 case WDIOC_GETSUPPORT:
159 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
160 case WDIOC_GETSTATUS:
161 case WDIOC_GETBOOTSTATUS:
162 return put_user(0, p);
163 case WDIOC_KEEPALIVE:
164 mpc8xxx_wdt_keepalive();
165 return 0;
166 case WDIOC_GETTIMEOUT:
167 return put_user(timeout_sec, p);
168 default:
169 return -ENOTTY;
170 }
171}
172
173static const struct file_operations mpc8xxx_wdt_fops = {
174 .owner = THIS_MODULE,
175 .llseek = no_llseek,
176 .write = mpc8xxx_wdt_write,
177 .unlocked_ioctl = mpc8xxx_wdt_ioctl,
178 .open = mpc8xxx_wdt_open,
179 .release = mpc8xxx_wdt_release,
180};
181
182static struct miscdevice mpc8xxx_wdt_miscdev = {
183 .minor = WATCHDOG_MINOR,
184 .name = "watchdog",
185 .fops = &mpc8xxx_wdt_fops,
186};
187
188static int __devinit mpc8xxx_wdt_probe(struct of_device *ofdev,
189 const struct of_device_id *match)
190{
191 int ret;
192 struct device_node *np = ofdev->node;
193 struct mpc8xxx_wdt_type *wdt_type = match->data;
194 u32 freq = fsl_get_sys_freq();
195 bool enabled;
196
197 if (!freq || freq == -1)
198 return -EINVAL;
199
200 wd_base = of_iomap(np, 0);
201 if (!wd_base)
202 return -ENOMEM;
203
204 enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
205 if (!enabled && wdt_type->hw_enabled) {
206 pr_info("mpc8xxx_wdt: could not be enabled in software\n");
207 ret = -ENOSYS;
208 goto err_unmap;
209 }
210
211
212 if (prescale)
213 timeout_sec = (timeout * wdt_type->prescaler) / freq;
214 else
215 timeout_sec = timeout / freq;
216
217#ifdef MODULE
218 ret = mpc8xxx_wdt_init_late();
219 if (ret)
220 goto err_unmap;
221#endif
222
223 pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d "
224 "(%d seconds)\n", reset ? "reset" : "interrupt", timeout,
225 timeout_sec);
226
227
228
229
230
231
232 if (enabled)
233 mpc8xxx_wdt_timer_ping(0);
234 return 0;
235err_unmap:
236 iounmap(wd_base);
237 wd_base = NULL;
238 return ret;
239}
240
241static int __devexit mpc8xxx_wdt_remove(struct of_device *ofdev)
242{
243 mpc8xxx_wdt_pr_warn("watchdog removed");
244 del_timer_sync(&wdt_timer);
245 misc_deregister(&mpc8xxx_wdt_miscdev);
246 iounmap(wd_base);
247
248 return 0;
249}
250
251static const struct of_device_id mpc8xxx_wdt_match[] = {
252 {
253 .compatible = "mpc83xx_wdt",
254 .data = &(struct mpc8xxx_wdt_type) {
255 .prescaler = 0x10000,
256 },
257 },
258 {
259 .compatible = "fsl,mpc8610-wdt",
260 .data = &(struct mpc8xxx_wdt_type) {
261 .prescaler = 0x10000,
262 .hw_enabled = true,
263 },
264 },
265 {
266 .compatible = "fsl,mpc823-wdt",
267 .data = &(struct mpc8xxx_wdt_type) {
268 .prescaler = 0x800,
269 },
270 },
271 {},
272};
273MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
274
275static struct of_platform_driver mpc8xxx_wdt_driver = {
276 .match_table = mpc8xxx_wdt_match,
277 .probe = mpc8xxx_wdt_probe,
278 .remove = __devexit_p(mpc8xxx_wdt_remove),
279 .driver = {
280 .name = "mpc8xxx_wdt",
281 .owner = THIS_MODULE,
282 },
283};
284
285
286
287
288
289
290static int mpc8xxx_wdt_init_late(void)
291{
292 int ret;
293
294 if (!wd_base)
295 return -ENODEV;
296
297 ret = misc_register(&mpc8xxx_wdt_miscdev);
298 if (ret) {
299 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
300 WATCHDOG_MINOR, ret);
301 return ret;
302 }
303 return 0;
304}
305#ifndef MODULE
306module_init(mpc8xxx_wdt_init_late);
307#endif
308
309static int __init mpc8xxx_wdt_init(void)
310{
311 return of_register_platform_driver(&mpc8xxx_wdt_driver);
312}
313arch_initcall(mpc8xxx_wdt_init);
314
315static void __exit mpc8xxx_wdt_exit(void)
316{
317 of_unregister_platform_driver(&mpc8xxx_wdt_driver);
318}
319module_exit(mpc8xxx_wdt_exit);
320
321MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
322MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
323 "uProcessors");
324MODULE_LICENSE("GPL");
325MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
326
