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1/*
2 * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
3 *
4 * Authors: Dave Updegraff <dave@cray.org>
5 * Kumar Gala <galak@kernel.crashing.org>
6 * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
7 * ..and from sc520_wdt
8 * Copyright (c) 2008 MontaVista Software, Inc.
9 * Anton Vorontsov <avorontsov@ru.mvista.com>
10 *
11 * Note: it appears that you can only actually ENABLE or DISABLE the thing
12 * once after POR. Once enabled, you cannot disable, and vice versa.
13 *
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License as published by the
16 * Free Software Foundation; either version 2 of the License, or (at your
17 * option) any later version.
18 */
19
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; /* System watchdog control register */
35#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
36#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
37#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
38#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
39 __be32 swcnr; /* System watchdog count register */
40 u8 res1[2];
41 __be16 swsrr; /* System watchdog service register */
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 * We always prescale, but if someone really doesn't want to they can set this
70 * to 0
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 /* Ping the WDT */
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 /* We're pinging it twice faster than needed, just to be sure. */
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 /* Once we start the watchdog we can't stop it */
118 if (nowayout)
119 __module_get(THIS_MODULE);
120
121 /* Good, fire up the show */
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 const 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 const struct of_device_id mpc8xxx_wdt_match[];
189static int __devinit mpc8xxx_wdt_probe(struct platform_device *ofdev)
190{
191 int ret;
192 const struct of_device_id *match;
193 struct device_node *np = ofdev->dev.of_node;
194 struct mpc8xxx_wdt_type *wdt_type;
195 u32 freq = fsl_get_sys_freq();
196 bool enabled;
197
198 match = of_match_device(mpc8xxx_wdt_match, &ofdev->dev);
199 if (!match)
200 return -EINVAL;
201 wdt_type = match->data;
202
203 if (!freq || freq == -1)
204 return -EINVAL;
205
206 wd_base = of_iomap(np, 0);
207 if (!wd_base)
208 return -ENOMEM;
209
210 enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
211 if (!enabled && wdt_type->hw_enabled) {
212 pr_info("mpc8xxx_wdt: could not be enabled in software\n");
213 ret = -ENOSYS;
214 goto err_unmap;
215 }
216
217 /* Calculate the timeout in seconds */
218 if (prescale)
219 timeout_sec = (timeout * wdt_type->prescaler) / freq;
220 else
221 timeout_sec = timeout / freq;
222
223#ifdef MODULE
224 ret = mpc8xxx_wdt_init_late();
225 if (ret)
226 goto err_unmap;
227#endif
228
229 pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d "
230 "(%d seconds)\n", reset ? "reset" : "interrupt", timeout,
231 timeout_sec);
232
233 /*
234 * If the watchdog was previously enabled or we're running on
235 * MPC8xxx, we should ping the wdt from the kernel until the
236 * userspace handles it.
237 */
238 if (enabled)
239 mpc8xxx_wdt_timer_ping(0);
240 return 0;
241err_unmap:
242 iounmap(wd_base);
243 wd_base = NULL;
244 return ret;
245}
246
247static int __devexit mpc8xxx_wdt_remove(struct platform_device *ofdev)
248{
249 mpc8xxx_wdt_pr_warn("watchdog removed");
250 del_timer_sync(&wdt_timer);
251 misc_deregister(&mpc8xxx_wdt_miscdev);
252 iounmap(wd_base);
253
254 return 0;
255}
256
257static const struct of_device_id mpc8xxx_wdt_match[] = {
258 {
259 .compatible = "mpc83xx_wdt",
260 .data = &(struct mpc8xxx_wdt_type) {
261 .prescaler = 0x10000,
262 },
263 },
264 {
265 .compatible = "fsl,mpc8610-wdt",
266 .data = &(struct mpc8xxx_wdt_type) {
267 .prescaler = 0x10000,
268 .hw_enabled = true,
269 },
270 },
271 {
272 .compatible = "fsl,mpc823-wdt",
273 .data = &(struct mpc8xxx_wdt_type) {
274 .prescaler = 0x800,
275 },
276 },
277 {},
278};
279MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
280
281static struct platform_driver mpc8xxx_wdt_driver = {
282 .probe = mpc8xxx_wdt_probe,
283 .remove = __devexit_p(mpc8xxx_wdt_remove),
284 .driver = {
285 .name = "mpc8xxx_wdt",
286 .owner = THIS_MODULE,
287 .of_match_table = mpc8xxx_wdt_match,
288 },
289};
290
291/*
292 * We do wdt initialization in two steps: arch_initcall probes the wdt
293 * very early to start pinging the watchdog (misc devices are not yet
294 * available), and later module_init() just registers the misc device.
295 */
296static int mpc8xxx_wdt_init_late(void)
297{
298 int ret;
299
300 if (!wd_base)
301 return -ENODEV;
302
303 ret = misc_register(&mpc8xxx_wdt_miscdev);
304 if (ret) {
305 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
306 WATCHDOG_MINOR, ret);
307 return ret;
308 }
309 return 0;
310}
311#ifndef MODULE
312module_init(mpc8xxx_wdt_init_late);
313#endif
314
315static int __init mpc8xxx_wdt_init(void)
316{
317 return platform_driver_register(&mpc8xxx_wdt_driver);
318}
319arch_initcall(mpc8xxx_wdt_init);
320
321static void __exit mpc8xxx_wdt_exit(void)
322{
323 platform_driver_unregister(&mpc8xxx_wdt_driver);
324}
325module_exit(mpc8xxx_wdt_exit);
326
327MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
328MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
329 "uProcessors");
330MODULE_LICENSE("GPL");
331MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
1/*
2 * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
3 *
4 * Authors: Dave Updegraff <dave@cray.org>
5 * Kumar Gala <galak@kernel.crashing.org>
6 * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
7 * ..and from sc520_wdt
8 * Copyright (c) 2008 MontaVista Software, Inc.
9 * Anton Vorontsov <avorontsov@ru.mvista.com>
10 *
11 * Note: it appears that you can only actually ENABLE or DISABLE the thing
12 * once after POR. Once enabled, you cannot disable, and vice versa.
13 *
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License as published by the
16 * Free Software Foundation; either version 2 of the License, or (at your
17 * option) any later version.
18 */
19
20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22#include <linux/fs.h>
23#include <linux/init.h>
24#include <linux/kernel.h>
25#include <linux/timer.h>
26#include <linux/miscdevice.h>
27#include <linux/of_address.h>
28#include <linux/of_platform.h>
29#include <linux/module.h>
30#include <linux/watchdog.h>
31#include <linux/io.h>
32#include <linux/uaccess.h>
33#include <sysdev/fsl_soc.h>
34
35struct mpc8xxx_wdt {
36 __be32 res0;
37 __be32 swcrr; /* System watchdog control register */
38#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
39#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
40#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
41#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
42 __be32 swcnr; /* System watchdog count register */
43 u8 res1[2];
44 __be16 swsrr; /* System watchdog service register */
45 u8 res2[0xF0];
46};
47
48struct mpc8xxx_wdt_type {
49 int prescaler;
50 bool hw_enabled;
51};
52
53static struct mpc8xxx_wdt __iomem *wd_base;
54static int mpc8xxx_wdt_init_late(void);
55
56static u16 timeout = 0xffff;
57module_param(timeout, ushort, 0);
58MODULE_PARM_DESC(timeout,
59 "Watchdog timeout in ticks. (0<timeout<65536, default=65535)");
60
61static bool reset = 1;
62module_param(reset, bool, 0);
63MODULE_PARM_DESC(reset,
64 "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
65
66static bool nowayout = WATCHDOG_NOWAYOUT;
67module_param(nowayout, bool, 0);
68MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
69 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
70
71/*
72 * We always prescale, but if someone really doesn't want to they can set this
73 * to 0
74 */
75static int prescale = 1;
76
77static DEFINE_SPINLOCK(wdt_spinlock);
78
79static void mpc8xxx_wdt_keepalive(void)
80{
81 /* Ping the WDT */
82 spin_lock(&wdt_spinlock);
83 out_be16(&wd_base->swsrr, 0x556c);
84 out_be16(&wd_base->swsrr, 0xaa39);
85 spin_unlock(&wdt_spinlock);
86}
87
88static struct watchdog_device mpc8xxx_wdt_dev;
89static void mpc8xxx_wdt_timer_ping(unsigned long arg);
90static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0,
91 (unsigned long)&mpc8xxx_wdt_dev);
92
93static void mpc8xxx_wdt_timer_ping(unsigned long arg)
94{
95 struct watchdog_device *w = (struct watchdog_device *)arg;
96
97 mpc8xxx_wdt_keepalive();
98 /* We're pinging it twice faster than needed, just to be sure. */
99 mod_timer(&wdt_timer, jiffies + HZ * w->timeout / 2);
100}
101
102static int mpc8xxx_wdt_start(struct watchdog_device *w)
103{
104 u32 tmp = SWCRR_SWEN;
105
106 /* Good, fire up the show */
107 if (prescale)
108 tmp |= SWCRR_SWPR;
109 if (reset)
110 tmp |= SWCRR_SWRI;
111
112 tmp |= timeout << 16;
113
114 out_be32(&wd_base->swcrr, tmp);
115
116 del_timer_sync(&wdt_timer);
117
118 return 0;
119}
120
121static int mpc8xxx_wdt_ping(struct watchdog_device *w)
122{
123 mpc8xxx_wdt_keepalive();
124 return 0;
125}
126
127static int mpc8xxx_wdt_stop(struct watchdog_device *w)
128{
129 mod_timer(&wdt_timer, jiffies);
130 return 0;
131}
132
133static struct watchdog_info mpc8xxx_wdt_info = {
134 .options = WDIOF_KEEPALIVEPING,
135 .firmware_version = 1,
136 .identity = "MPC8xxx",
137};
138
139static struct watchdog_ops mpc8xxx_wdt_ops = {
140 .owner = THIS_MODULE,
141 .start = mpc8xxx_wdt_start,
142 .ping = mpc8xxx_wdt_ping,
143 .stop = mpc8xxx_wdt_stop,
144};
145
146static struct watchdog_device mpc8xxx_wdt_dev = {
147 .info = &mpc8xxx_wdt_info,
148 .ops = &mpc8xxx_wdt_ops,
149};
150
151static const struct of_device_id mpc8xxx_wdt_match[];
152static int mpc8xxx_wdt_probe(struct platform_device *ofdev)
153{
154 int ret;
155 const struct of_device_id *match;
156 struct device_node *np = ofdev->dev.of_node;
157 const struct mpc8xxx_wdt_type *wdt_type;
158 u32 freq = fsl_get_sys_freq();
159 bool enabled;
160 unsigned int timeout_sec;
161
162 match = of_match_device(mpc8xxx_wdt_match, &ofdev->dev);
163 if (!match)
164 return -EINVAL;
165 wdt_type = match->data;
166
167 if (!freq || freq == -1)
168 return -EINVAL;
169
170 wd_base = of_iomap(np, 0);
171 if (!wd_base)
172 return -ENOMEM;
173
174 enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
175 if (!enabled && wdt_type->hw_enabled) {
176 pr_info("could not be enabled in software\n");
177 ret = -ENOSYS;
178 goto err_unmap;
179 }
180
181 /* Calculate the timeout in seconds */
182 if (prescale)
183 timeout_sec = (timeout * wdt_type->prescaler) / freq;
184 else
185 timeout_sec = timeout / freq;
186
187 mpc8xxx_wdt_dev.timeout = timeout_sec;
188#ifdef MODULE
189 ret = mpc8xxx_wdt_init_late();
190 if (ret)
191 goto err_unmap;
192#endif
193
194 pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d (%d seconds)\n",
195 reset ? "reset" : "interrupt", timeout, timeout_sec);
196
197 /*
198 * If the watchdog was previously enabled or we're running on
199 * MPC8xxx, we should ping the wdt from the kernel until the
200 * userspace handles it.
201 */
202 if (enabled)
203 mod_timer(&wdt_timer, jiffies);
204 return 0;
205err_unmap:
206 iounmap(wd_base);
207 wd_base = NULL;
208 return ret;
209}
210
211static int mpc8xxx_wdt_remove(struct platform_device *ofdev)
212{
213 pr_crit("Watchdog removed, expect the %s soon!\n",
214 reset ? "reset" : "machine check exception");
215 del_timer_sync(&wdt_timer);
216 watchdog_unregister_device(&mpc8xxx_wdt_dev);
217 iounmap(wd_base);
218
219 return 0;
220}
221
222static const struct of_device_id mpc8xxx_wdt_match[] = {
223 {
224 .compatible = "mpc83xx_wdt",
225 .data = &(struct mpc8xxx_wdt_type) {
226 .prescaler = 0x10000,
227 },
228 },
229 {
230 .compatible = "fsl,mpc8610-wdt",
231 .data = &(struct mpc8xxx_wdt_type) {
232 .prescaler = 0x10000,
233 .hw_enabled = true,
234 },
235 },
236 {
237 .compatible = "fsl,mpc823-wdt",
238 .data = &(struct mpc8xxx_wdt_type) {
239 .prescaler = 0x800,
240 .hw_enabled = true,
241 },
242 },
243 {},
244};
245MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
246
247static struct platform_driver mpc8xxx_wdt_driver = {
248 .probe = mpc8xxx_wdt_probe,
249 .remove = mpc8xxx_wdt_remove,
250 .driver = {
251 .name = "mpc8xxx_wdt",
252 .owner = THIS_MODULE,
253 .of_match_table = mpc8xxx_wdt_match,
254 },
255};
256
257/*
258 * We do wdt initialization in two steps: arch_initcall probes the wdt
259 * very early to start pinging the watchdog (misc devices are not yet
260 * available), and later module_init() just registers the misc device.
261 */
262static int mpc8xxx_wdt_init_late(void)
263{
264 int ret;
265
266 if (!wd_base)
267 return -ENODEV;
268
269 watchdog_set_nowayout(&mpc8xxx_wdt_dev, nowayout);
270
271 ret = watchdog_register_device(&mpc8xxx_wdt_dev);
272 if (ret) {
273 pr_err("cannot register watchdog device (err=%d)\n", ret);
274 return ret;
275 }
276 return 0;
277}
278#ifndef MODULE
279module_init(mpc8xxx_wdt_init_late);
280#endif
281
282static int __init mpc8xxx_wdt_init(void)
283{
284 return platform_driver_register(&mpc8xxx_wdt_driver);
285}
286arch_initcall(mpc8xxx_wdt_init);
287
288static void __exit mpc8xxx_wdt_exit(void)
289{
290 platform_driver_unregister(&mpc8xxx_wdt_driver);
291}
292module_exit(mpc8xxx_wdt_exit);
293
294MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
295MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
296 "uProcessors");
297MODULE_LICENSE("GPL");