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Commit | Line | Data |
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fabbfb9e | 1 | /* |
0d7b1014 | 2 | * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface |
fabbfb9e KG |
3 | * |
4 | * Authors: Dave Updegraff <dave@cray.org> | |
5f3b2756 WVS |
5 | * Kumar Gala <galak@kernel.crashing.org> |
6 | * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org> | |
7 | * ..and from sc520_wdt | |
500c919e AV |
8 | * Copyright (c) 2008 MontaVista Software, Inc. |
9 | * Anton Vorontsov <avorontsov@ru.mvista.com> | |
fabbfb9e KG |
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 | ||
27c766aa JP |
20 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
21 | ||
fabbfb9e KG |
22 | #include <linux/fs.h> |
23 | #include <linux/init.h> | |
24 | #include <linux/kernel.h> | |
500c919e | 25 | #include <linux/timer.h> |
fabbfb9e | 26 | #include <linux/miscdevice.h> |
5af50730 | 27 | #include <linux/of_address.h> |
ef8ab12e | 28 | #include <linux/of_platform.h> |
fabbfb9e KG |
29 | #include <linux/module.h> |
30 | #include <linux/watchdog.h> | |
f26ef3dc AC |
31 | #include <linux/io.h> |
32 | #include <linux/uaccess.h> | |
ef8ab12e | 33 | #include <sysdev/fsl_soc.h> |
fabbfb9e | 34 | |
59ca1b0d | 35 | struct mpc8xxx_wdt { |
fabbfb9e KG |
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 | ||
59ca1b0d | 48 | struct mpc8xxx_wdt_type { |
500c919e AV |
49 | int prescaler; |
50 | bool hw_enabled; | |
51 | }; | |
52 | ||
59ca1b0d | 53 | static struct mpc8xxx_wdt __iomem *wd_base; |
593fc178 | 54 | static int mpc8xxx_wdt_init_late(void); |
fabbfb9e KG |
55 | |
56 | static u16 timeout = 0xffff; | |
57 | module_param(timeout, ushort, 0); | |
f26ef3dc | 58 | MODULE_PARM_DESC(timeout, |
76550d32 | 59 | "Watchdog timeout in ticks. (0<timeout<65536, default=65535)"); |
fabbfb9e | 60 | |
90ab5ee9 | 61 | static bool reset = 1; |
fabbfb9e | 62 | module_param(reset, bool, 0); |
f26ef3dc AC |
63 | MODULE_PARM_DESC(reset, |
64 | "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset"); | |
fabbfb9e | 65 | |
86a1e189 WVS |
66 | static bool nowayout = WATCHDOG_NOWAYOUT; |
67 | module_param(nowayout, bool, 0); | |
500c919e AV |
68 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " |
69 | "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
70 | ||
fabbfb9e KG |
71 | /* |
72 | * We always prescale, but if someone really doesn't want to they can set this | |
73 | * to 0 | |
74 | */ | |
75 | static int prescale = 1; | |
76 | static unsigned int timeout_sec; | |
77 | ||
78 | static unsigned long wdt_is_open; | |
c7dfd0cc | 79 | static DEFINE_SPINLOCK(wdt_spinlock); |
fabbfb9e | 80 | |
59ca1b0d | 81 | static void mpc8xxx_wdt_keepalive(void) |
fabbfb9e KG |
82 | { |
83 | /* Ping the WDT */ | |
84 | spin_lock(&wdt_spinlock); | |
85 | out_be16(&wd_base->swsrr, 0x556c); | |
86 | out_be16(&wd_base->swsrr, 0xaa39); | |
87 | spin_unlock(&wdt_spinlock); | |
88 | } | |
89 | ||
59ca1b0d AV |
90 | static void mpc8xxx_wdt_timer_ping(unsigned long arg); |
91 | static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, 0); | |
500c919e | 92 | |
59ca1b0d | 93 | static void mpc8xxx_wdt_timer_ping(unsigned long arg) |
500c919e | 94 | { |
59ca1b0d | 95 | mpc8xxx_wdt_keepalive(); |
500c919e AV |
96 | /* We're pinging it twice faster than needed, just to be sure. */ |
97 | mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2); | |
98 | } | |
99 | ||
59ca1b0d | 100 | static void mpc8xxx_wdt_pr_warn(const char *msg) |
500c919e | 101 | { |
27c766aa | 102 | pr_crit("%s, expect the %s soon!\n", msg, |
500c919e AV |
103 | reset ? "reset" : "machine check exception"); |
104 | } | |
105 | ||
59ca1b0d | 106 | static ssize_t mpc8xxx_wdt_write(struct file *file, const char __user *buf, |
fabbfb9e KG |
107 | size_t count, loff_t *ppos) |
108 | { | |
109 | if (count) | |
59ca1b0d | 110 | mpc8xxx_wdt_keepalive(); |
fabbfb9e KG |
111 | return count; |
112 | } | |
113 | ||
59ca1b0d | 114 | static int mpc8xxx_wdt_open(struct inode *inode, struct file *file) |
fabbfb9e KG |
115 | { |
116 | u32 tmp = SWCRR_SWEN; | |
117 | if (test_and_set_bit(0, &wdt_is_open)) | |
118 | return -EBUSY; | |
119 | ||
120 | /* Once we start the watchdog we can't stop it */ | |
500c919e AV |
121 | if (nowayout) |
122 | __module_get(THIS_MODULE); | |
fabbfb9e KG |
123 | |
124 | /* Good, fire up the show */ | |
125 | if (prescale) | |
126 | tmp |= SWCRR_SWPR; | |
127 | if (reset) | |
128 | tmp |= SWCRR_SWRI; | |
129 | ||
130 | tmp |= timeout << 16; | |
131 | ||
132 | out_be32(&wd_base->swcrr, tmp); | |
133 | ||
500c919e AV |
134 | del_timer_sync(&wdt_timer); |
135 | ||
fabbfb9e KG |
136 | return nonseekable_open(inode, file); |
137 | } | |
138 | ||
59ca1b0d | 139 | static int mpc8xxx_wdt_release(struct inode *inode, struct file *file) |
fabbfb9e | 140 | { |
500c919e | 141 | if (!nowayout) |
59ca1b0d | 142 | mpc8xxx_wdt_timer_ping(0); |
500c919e | 143 | else |
59ca1b0d | 144 | mpc8xxx_wdt_pr_warn("watchdog closed"); |
fabbfb9e KG |
145 | clear_bit(0, &wdt_is_open); |
146 | return 0; | |
147 | } | |
148 | ||
cb55d282 | 149 | static long mpc8xxx_wdt_ioctl(struct file *file, unsigned int cmd, |
f26ef3dc | 150 | unsigned long arg) |
fabbfb9e KG |
151 | { |
152 | void __user *argp = (void __user *)arg; | |
153 | int __user *p = argp; | |
42747d71 | 154 | static const struct watchdog_info ident = { |
fabbfb9e KG |
155 | .options = WDIOF_KEEPALIVEPING, |
156 | .firmware_version = 1, | |
59ca1b0d | 157 | .identity = "MPC8xxx", |
fabbfb9e KG |
158 | }; |
159 | ||
160 | switch (cmd) { | |
161 | case WDIOC_GETSUPPORT: | |
162 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
5c4eb61b WVS |
163 | case WDIOC_GETSTATUS: |
164 | case WDIOC_GETBOOTSTATUS: | |
165 | return put_user(0, p); | |
fabbfb9e | 166 | case WDIOC_KEEPALIVE: |
59ca1b0d | 167 | mpc8xxx_wdt_keepalive(); |
fabbfb9e KG |
168 | return 0; |
169 | case WDIOC_GETTIMEOUT: | |
170 | return put_user(timeout_sec, p); | |
171 | default: | |
795b89d2 | 172 | return -ENOTTY; |
fabbfb9e KG |
173 | } |
174 | } | |
175 | ||
59ca1b0d | 176 | static const struct file_operations mpc8xxx_wdt_fops = { |
fabbfb9e KG |
177 | .owner = THIS_MODULE, |
178 | .llseek = no_llseek, | |
59ca1b0d AV |
179 | .write = mpc8xxx_wdt_write, |
180 | .unlocked_ioctl = mpc8xxx_wdt_ioctl, | |
181 | .open = mpc8xxx_wdt_open, | |
182 | .release = mpc8xxx_wdt_release, | |
fabbfb9e KG |
183 | }; |
184 | ||
59ca1b0d | 185 | static struct miscdevice mpc8xxx_wdt_miscdev = { |
fabbfb9e KG |
186 | .minor = WATCHDOG_MINOR, |
187 | .name = "watchdog", | |
59ca1b0d | 188 | .fops = &mpc8xxx_wdt_fops, |
fabbfb9e KG |
189 | }; |
190 | ||
b1608d69 | 191 | static const struct of_device_id mpc8xxx_wdt_match[]; |
2d991a16 | 192 | static int mpc8xxx_wdt_probe(struct platform_device *ofdev) |
fabbfb9e | 193 | { |
fabbfb9e | 194 | int ret; |
b1608d69 | 195 | const struct of_device_id *match; |
de2b606c | 196 | struct device_node *np = ofdev->dev.of_node; |
639397e4 | 197 | const struct mpc8xxx_wdt_type *wdt_type; |
ef8ab12e | 198 | u32 freq = fsl_get_sys_freq(); |
500c919e | 199 | bool enabled; |
fabbfb9e | 200 | |
b1608d69 GL |
201 | match = of_match_device(mpc8xxx_wdt_match, &ofdev->dev); |
202 | if (!match) | |
1c48a5c9 | 203 | return -EINVAL; |
b1608d69 | 204 | wdt_type = match->data; |
1c48a5c9 | 205 | |
ef8ab12e AV |
206 | if (!freq || freq == -1) |
207 | return -EINVAL; | |
fabbfb9e | 208 | |
500c919e | 209 | wd_base = of_iomap(np, 0); |
ef8ab12e AV |
210 | if (!wd_base) |
211 | return -ENOMEM; | |
fabbfb9e | 212 | |
500c919e AV |
213 | enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN; |
214 | if (!enabled && wdt_type->hw_enabled) { | |
27c766aa | 215 | pr_info("could not be enabled in software\n"); |
500c919e AV |
216 | ret = -ENOSYS; |
217 | goto err_unmap; | |
218 | } | |
219 | ||
fabbfb9e KG |
220 | /* Calculate the timeout in seconds */ |
221 | if (prescale) | |
500c919e | 222 | timeout_sec = (timeout * wdt_type->prescaler) / freq; |
fabbfb9e | 223 | else |
ef8ab12e | 224 | timeout_sec = timeout / freq; |
fabbfb9e | 225 | |
593fc178 AV |
226 | #ifdef MODULE |
227 | ret = mpc8xxx_wdt_init_late(); | |
228 | if (ret) | |
229 | goto err_unmap; | |
230 | #endif | |
231 | ||
27c766aa JP |
232 | pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d (%d seconds)\n", |
233 | reset ? "reset" : "interrupt", timeout, timeout_sec); | |
500c919e AV |
234 | |
235 | /* | |
236 | * If the watchdog was previously enabled or we're running on | |
59ca1b0d | 237 | * MPC8xxx, we should ping the wdt from the kernel until the |
500c919e AV |
238 | * userspace handles it. |
239 | */ | |
240 | if (enabled) | |
59ca1b0d | 241 | mpc8xxx_wdt_timer_ping(0); |
fabbfb9e | 242 | return 0; |
fabbfb9e KG |
243 | err_unmap: |
244 | iounmap(wd_base); | |
0d7b1014 | 245 | wd_base = NULL; |
fabbfb9e KG |
246 | return ret; |
247 | } | |
248 | ||
4b12b896 | 249 | static int mpc8xxx_wdt_remove(struct platform_device *ofdev) |
fabbfb9e | 250 | { |
59ca1b0d | 251 | mpc8xxx_wdt_pr_warn("watchdog removed"); |
500c919e | 252 | del_timer_sync(&wdt_timer); |
59ca1b0d | 253 | misc_deregister(&mpc8xxx_wdt_miscdev); |
fabbfb9e KG |
254 | iounmap(wd_base); |
255 | ||
256 | return 0; | |
257 | } | |
258 | ||
59ca1b0d | 259 | static const struct of_device_id mpc8xxx_wdt_match[] = { |
ef8ab12e AV |
260 | { |
261 | .compatible = "mpc83xx_wdt", | |
59ca1b0d | 262 | .data = &(struct mpc8xxx_wdt_type) { |
500c919e AV |
263 | .prescaler = 0x10000, |
264 | }, | |
265 | }, | |
266 | { | |
267 | .compatible = "fsl,mpc8610-wdt", | |
59ca1b0d | 268 | .data = &(struct mpc8xxx_wdt_type) { |
500c919e AV |
269 | .prescaler = 0x10000, |
270 | .hw_enabled = true, | |
271 | }, | |
ef8ab12e | 272 | }, |
0d7b1014 AV |
273 | { |
274 | .compatible = "fsl,mpc823-wdt", | |
275 | .data = &(struct mpc8xxx_wdt_type) { | |
276 | .prescaler = 0x800, | |
277 | }, | |
278 | }, | |
ef8ab12e AV |
279 | {}, |
280 | }; | |
59ca1b0d | 281 | MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match); |
ef8ab12e | 282 | |
1c48a5c9 | 283 | static struct platform_driver mpc8xxx_wdt_driver = { |
59ca1b0d | 284 | .probe = mpc8xxx_wdt_probe, |
82268714 | 285 | .remove = mpc8xxx_wdt_remove, |
4018294b GL |
286 | .driver = { |
287 | .name = "mpc8xxx_wdt", | |
288 | .owner = THIS_MODULE, | |
289 | .of_match_table = mpc8xxx_wdt_match, | |
fabbfb9e KG |
290 | }, |
291 | }; | |
292 | ||
0d7b1014 AV |
293 | /* |
294 | * We do wdt initialization in two steps: arch_initcall probes the wdt | |
295 | * very early to start pinging the watchdog (misc devices are not yet | |
296 | * available), and later module_init() just registers the misc device. | |
297 | */ | |
593fc178 | 298 | static int mpc8xxx_wdt_init_late(void) |
0d7b1014 AV |
299 | { |
300 | int ret; | |
301 | ||
302 | if (!wd_base) | |
303 | return -ENODEV; | |
304 | ||
305 | ret = misc_register(&mpc8xxx_wdt_miscdev); | |
306 | if (ret) { | |
307 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", | |
27c766aa | 308 | WATCHDOG_MINOR, ret); |
0d7b1014 AV |
309 | return ret; |
310 | } | |
311 | return 0; | |
312 | } | |
593fc178 | 313 | #ifndef MODULE |
0d7b1014 | 314 | module_init(mpc8xxx_wdt_init_late); |
593fc178 | 315 | #endif |
0d7b1014 | 316 | |
59ca1b0d | 317 | static int __init mpc8xxx_wdt_init(void) |
fabbfb9e | 318 | { |
1c48a5c9 | 319 | return platform_driver_register(&mpc8xxx_wdt_driver); |
fabbfb9e | 320 | } |
0d7b1014 | 321 | arch_initcall(mpc8xxx_wdt_init); |
fabbfb9e | 322 | |
59ca1b0d | 323 | static void __exit mpc8xxx_wdt_exit(void) |
fabbfb9e | 324 | { |
1c48a5c9 | 325 | platform_driver_unregister(&mpc8xxx_wdt_driver); |
fabbfb9e | 326 | } |
59ca1b0d | 327 | module_exit(mpc8xxx_wdt_exit); |
fabbfb9e KG |
328 | |
329 | MODULE_AUTHOR("Dave Updegraff, Kumar Gala"); | |
0d7b1014 AV |
330 | MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx " |
331 | "uProcessors"); | |
fabbfb9e KG |
332 | MODULE_LICENSE("GPL"); |
333 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |