Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
9b0fd114 | 2 | /* Watchdog timer for machines with the CS5535/CS5536 companion chip |
0b36086b JC |
3 | * |
4 | * Copyright (C) 2006-2007, Advanced Micro Devices, Inc. | |
9b0fd114 | 5 | * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk> |
0b36086b JC |
6 | */ |
7 | ||
27c766aa | 8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
0b36086b JC |
9 | |
10 | #include <linux/module.h> | |
11 | #include <linux/moduleparam.h> | |
12 | #include <linux/types.h> | |
13 | #include <linux/miscdevice.h> | |
14 | #include <linux/watchdog.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/platform_device.h> | |
17 | #include <linux/reboot.h> | |
089ab079 | 18 | #include <linux/uaccess.h> |
0b36086b | 19 | |
9b0fd114 | 20 | #include <linux/cs5535.h> |
0b36086b JC |
21 | |
22 | #define GEODEWDT_HZ 500 | |
23 | #define GEODEWDT_SCALE 6 | |
24 | #define GEODEWDT_MAX_SECONDS 131 | |
25 | ||
26 | #define WDT_FLAGS_OPEN 1 | |
27 | #define WDT_FLAGS_ORPHAN 2 | |
28 | ||
29 | #define DRV_NAME "geodewdt" | |
30 | #define WATCHDOG_NAME "Geode GX/LX WDT" | |
31 | #define WATCHDOG_TIMEOUT 60 | |
32 | ||
33 | static int timeout = WATCHDOG_TIMEOUT; | |
34 | module_param(timeout, int, 0); | |
143a2e54 WVS |
35 | MODULE_PARM_DESC(timeout, |
36 | "Watchdog timeout in seconds. 1<= timeout <=131, default=" | |
37 | __MODULE_STRING(WATCHDOG_TIMEOUT) "."); | |
0b36086b | 38 | |
86a1e189 WVS |
39 | static bool nowayout = WATCHDOG_NOWAYOUT; |
40 | module_param(nowayout, bool, 0); | |
143a2e54 WVS |
41 | MODULE_PARM_DESC(nowayout, |
42 | "Watchdog cannot be stopped once started (default=" | |
43 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
0b36086b JC |
44 | |
45 | static struct platform_device *geodewdt_platform_device; | |
46 | static unsigned long wdt_flags; | |
9b0fd114 | 47 | static struct cs5535_mfgpt_timer *wdt_timer; |
0b36086b JC |
48 | static int safe_close; |
49 | ||
50 | static void geodewdt_ping(void) | |
51 | { | |
52 | /* Stop the counter */ | |
9b0fd114 | 53 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); |
0b36086b JC |
54 | |
55 | /* Reset the counter */ | |
9b0fd114 | 56 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); |
0b36086b JC |
57 | |
58 | /* Enable the counter */ | |
9b0fd114 | 59 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); |
0b36086b JC |
60 | } |
61 | ||
62 | static void geodewdt_disable(void) | |
63 | { | |
9b0fd114 AS |
64 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); |
65 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); | |
0b36086b JC |
66 | } |
67 | ||
68 | static int geodewdt_set_heartbeat(int val) | |
69 | { | |
70 | if (val < 1 || val > GEODEWDT_MAX_SECONDS) | |
71 | return -EINVAL; | |
72 | ||
9b0fd114 AS |
73 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); |
74 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ); | |
75 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); | |
76 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); | |
0b36086b JC |
77 | |
78 | timeout = val; | |
79 | return 0; | |
80 | } | |
81 | ||
7944d3a5 | 82 | static int geodewdt_open(struct inode *inode, struct file *file) |
0b36086b | 83 | { |
7944d3a5 WVS |
84 | if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags)) |
85 | return -EBUSY; | |
0b36086b | 86 | |
7944d3a5 WVS |
87 | if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags)) |
88 | __module_get(THIS_MODULE); | |
0b36086b JC |
89 | |
90 | geodewdt_ping(); | |
c5bf68fe | 91 | return stream_open(inode, file); |
0b36086b JC |
92 | } |
93 | ||
7944d3a5 | 94 | static int geodewdt_release(struct inode *inode, struct file *file) |
0b36086b JC |
95 | { |
96 | if (safe_close) { | |
97 | geodewdt_disable(); | |
98 | module_put(THIS_MODULE); | |
7944d3a5 | 99 | } else { |
27c766aa | 100 | pr_crit("Unexpected close - watchdog is not stopping\n"); |
0b36086b JC |
101 | geodewdt_ping(); |
102 | ||
103 | set_bit(WDT_FLAGS_ORPHAN, &wdt_flags); | |
104 | } | |
105 | ||
106 | clear_bit(WDT_FLAGS_OPEN, &wdt_flags); | |
107 | safe_close = 0; | |
108 | return 0; | |
109 | } | |
110 | ||
7944d3a5 WVS |
111 | static ssize_t geodewdt_write(struct file *file, const char __user *data, |
112 | size_t len, loff_t *ppos) | |
0b36086b | 113 | { |
7944d3a5 | 114 | if (len) { |
0b36086b JC |
115 | if (!nowayout) { |
116 | size_t i; | |
117 | safe_close = 0; | |
118 | ||
119 | for (i = 0; i != len; i++) { | |
120 | char c; | |
121 | ||
122 | if (get_user(c, data + i)) | |
123 | return -EFAULT; | |
124 | ||
125 | if (c == 'V') | |
126 | safe_close = 1; | |
127 | } | |
128 | } | |
129 | ||
130 | geodewdt_ping(); | |
131 | } | |
132 | return len; | |
133 | } | |
134 | ||
7275fc8c WVS |
135 | static long geodewdt_ioctl(struct file *file, unsigned int cmd, |
136 | unsigned long arg) | |
0b36086b JC |
137 | { |
138 | void __user *argp = (void __user *)arg; | |
139 | int __user *p = argp; | |
140 | int interval; | |
141 | ||
42747d71 | 142 | static const struct watchdog_info ident = { |
0b36086b JC |
143 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
144 | | WDIOF_MAGICCLOSE, | |
145 | .firmware_version = 1, | |
146 | .identity = WATCHDOG_NAME, | |
7944d3a5 | 147 | }; |
0b36086b | 148 | |
5eb82498 | 149 | switch (cmd) { |
0b36086b JC |
150 | case WDIOC_GETSUPPORT: |
151 | return copy_to_user(argp, &ident, | |
152 | sizeof(ident)) ? -EFAULT : 0; | |
0b36086b JC |
153 | case WDIOC_GETSTATUS: |
154 | case WDIOC_GETBOOTSTATUS: | |
155 | return put_user(0, p); | |
156 | ||
0b36086b JC |
157 | case WDIOC_SETOPTIONS: |
158 | { | |
159 | int options, ret = -EINVAL; | |
160 | ||
161 | if (get_user(options, p)) | |
162 | return -EFAULT; | |
163 | ||
164 | if (options & WDIOS_DISABLECARD) { | |
165 | geodewdt_disable(); | |
166 | ret = 0; | |
167 | } | |
168 | ||
169 | if (options & WDIOS_ENABLECARD) { | |
170 | geodewdt_ping(); | |
171 | ret = 0; | |
172 | } | |
173 | ||
174 | return ret; | |
175 | } | |
0c06090c WVS |
176 | case WDIOC_KEEPALIVE: |
177 | geodewdt_ping(); | |
178 | return 0; | |
179 | ||
180 | case WDIOC_SETTIMEOUT: | |
181 | if (get_user(interval, p)) | |
182 | return -EFAULT; | |
183 | ||
184 | if (geodewdt_set_heartbeat(interval)) | |
185 | return -EINVAL; | |
bd490f82 | 186 | fallthrough; |
0c06090c WVS |
187 | case WDIOC_GETTIMEOUT: |
188 | return put_user(timeout, p); | |
189 | ||
0b36086b JC |
190 | default: |
191 | return -ENOTTY; | |
192 | } | |
193 | ||
194 | return 0; | |
195 | } | |
196 | ||
197 | static const struct file_operations geodewdt_fops = { | |
7944d3a5 WVS |
198 | .owner = THIS_MODULE, |
199 | .llseek = no_llseek, | |
200 | .write = geodewdt_write, | |
7275fc8c | 201 | .unlocked_ioctl = geodewdt_ioctl, |
b6dfb247 | 202 | .compat_ioctl = compat_ptr_ioctl, |
7944d3a5 WVS |
203 | .open = geodewdt_open, |
204 | .release = geodewdt_release, | |
0b36086b JC |
205 | }; |
206 | ||
207 | static struct miscdevice geodewdt_miscdev = { | |
208 | .minor = WATCHDOG_MINOR, | |
209 | .name = "watchdog", | |
7944d3a5 | 210 | .fops = &geodewdt_fops, |
0b36086b JC |
211 | }; |
212 | ||
78411be4 | 213 | static int __init geodewdt_probe(struct platform_device *dev) |
0b36086b | 214 | { |
9b0fd114 | 215 | int ret; |
0b36086b | 216 | |
9b0fd114 AS |
217 | wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING); |
218 | if (!wdt_timer) { | |
27c766aa | 219 | pr_err("No timers were available\n"); |
0b36086b JC |
220 | return -ENODEV; |
221 | } | |
222 | ||
0b36086b JC |
223 | /* Set up the timer */ |
224 | ||
9b0fd114 | 225 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, |
0b36086b JC |
226 | GEODEWDT_SCALE | (3 << 8)); |
227 | ||
228 | /* Set up comparator 2 to reset when the event fires */ | |
9b0fd114 | 229 | cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1); |
0b36086b JC |
230 | |
231 | /* Set up the initial timeout */ | |
232 | ||
9b0fd114 | 233 | cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, |
0b36086b JC |
234 | timeout * GEODEWDT_HZ); |
235 | ||
236 | ret = misc_register(&geodewdt_miscdev); | |
237 | ||
238 | return ret; | |
239 | } | |
240 | ||
4b12b896 | 241 | static int geodewdt_remove(struct platform_device *dev) |
0b36086b JC |
242 | { |
243 | misc_deregister(&geodewdt_miscdev); | |
244 | return 0; | |
245 | } | |
246 | ||
7944d3a5 | 247 | static void geodewdt_shutdown(struct platform_device *dev) |
0b36086b JC |
248 | { |
249 | geodewdt_disable(); | |
250 | } | |
251 | ||
252 | static struct platform_driver geodewdt_driver = { | |
82268714 | 253 | .remove = geodewdt_remove, |
0b36086b JC |
254 | .shutdown = geodewdt_shutdown, |
255 | .driver = { | |
0b36086b JC |
256 | .name = DRV_NAME, |
257 | }, | |
258 | }; | |
259 | ||
7944d3a5 | 260 | static int __init geodewdt_init(void) |
0b36086b JC |
261 | { |
262 | int ret; | |
263 | ||
143a2e54 WVS |
264 | geodewdt_platform_device = platform_device_register_simple(DRV_NAME, |
265 | -1, NULL, 0); | |
78411be4 JD |
266 | if (IS_ERR(geodewdt_platform_device)) |
267 | return PTR_ERR(geodewdt_platform_device); | |
268 | ||
269 | ret = platform_driver_probe(&geodewdt_driver, geodewdt_probe); | |
270 | if (ret) | |
0b36086b | 271 | goto err; |
0b36086b JC |
272 | |
273 | return 0; | |
274 | err: | |
78411be4 | 275 | platform_device_unregister(geodewdt_platform_device); |
0b36086b JC |
276 | return ret; |
277 | } | |
278 | ||
7944d3a5 | 279 | static void __exit geodewdt_exit(void) |
0b36086b JC |
280 | { |
281 | platform_device_unregister(geodewdt_platform_device); | |
282 | platform_driver_unregister(&geodewdt_driver); | |
283 | } | |
284 | ||
285 | module_init(geodewdt_init); | |
286 | module_exit(geodewdt_exit); | |
287 | ||
288 | MODULE_AUTHOR("Advanced Micro Devices, Inc"); | |
289 | MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver"); | |
290 | MODULE_LICENSE("GPL"); |