Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
ccb8f430 AV |
2 | /* |
3 | * Watchdog driver for Kendin/Micrel KS8695. | |
4 | * | |
5 | * (C) 2007 Andrew Victor | |
ccb8f430 AV |
6 | */ |
7 | ||
27c766aa JP |
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
9 | ||
1977f032 | 10 | #include <linux/bitops.h> |
ccb8f430 AV |
11 | #include <linux/errno.h> |
12 | #include <linux/fs.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/miscdevice.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/moduleparam.h> | |
18 | #include <linux/platform_device.h> | |
19 | #include <linux/types.h> | |
20 | #include <linux/watchdog.h> | |
f4fabce1 AC |
21 | #include <linux/io.h> |
22 | #include <linux/uaccess.h> | |
568dba66 | 23 | #include <mach/hardware.h> |
cab463a2 LW |
24 | |
25 | #define KS8695_TMR_OFFSET (0xF0000 + 0xE400) | |
26 | #define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET) | |
27 | ||
28 | /* | |
29 | * Timer registers | |
30 | */ | |
31 | #define KS8695_TMCON (0x00) /* Timer Control Register */ | |
32 | #define KS8695_T0TC (0x08) /* Timer 0 Timeout Count Register */ | |
33 | #define TMCON_T0EN (1 << 0) /* Timer 0 Enable */ | |
34 | ||
35 | /* Timer0 Timeout Counter Register */ | |
36 | #define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */ | |
ccb8f430 | 37 | |
ccb8f430 AV |
38 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
39 | #define WDT_MAX_TIME 171 /* seconds */ | |
40 | ||
41 | static int wdt_time = WDT_DEFAULT_TIME; | |
86a1e189 | 42 | static bool nowayout = WATCHDOG_NOWAYOUT; |
ccb8f430 AV |
43 | |
44 | module_param(wdt_time, int, 0); | |
f4fabce1 AC |
45 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
46 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); | |
ccb8f430 AV |
47 | |
48 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | |
86a1e189 | 49 | module_param(nowayout, bool, 0); |
f4fabce1 AC |
50 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
51 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
ccb8f430 AV |
52 | #endif |
53 | ||
54 | ||
55 | static unsigned long ks8695wdt_busy; | |
1334f329 | 56 | static DEFINE_SPINLOCK(ks8695_lock); |
ccb8f430 AV |
57 | |
58 | /* ......................................................................... */ | |
59 | ||
60 | /* | |
61 | * Disable the watchdog. | |
62 | */ | |
f4fabce1 | 63 | static inline void ks8695_wdt_stop(void) |
ccb8f430 AV |
64 | { |
65 | unsigned long tmcon; | |
66 | ||
f4fabce1 | 67 | spin_lock(&ks8695_lock); |
ccb8f430 AV |
68 | /* disable timer0 */ |
69 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); | |
70 | __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); | |
f4fabce1 | 71 | spin_unlock(&ks8695_lock); |
ccb8f430 AV |
72 | } |
73 | ||
74 | /* | |
75 | * Enable and reset the watchdog. | |
76 | */ | |
f4fabce1 | 77 | static inline void ks8695_wdt_start(void) |
ccb8f430 AV |
78 | { |
79 | unsigned long tmcon; | |
0a51810a | 80 | unsigned long tval = wdt_time * KS8695_CLOCK_RATE; |
ccb8f430 | 81 | |
f4fabce1 | 82 | spin_lock(&ks8695_lock); |
ccb8f430 AV |
83 | /* disable timer0 */ |
84 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); | |
85 | __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); | |
86 | ||
87 | /* program timer0 */ | |
88 | __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC); | |
89 | ||
90 | /* re-enable timer0 */ | |
91 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); | |
92 | __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); | |
f4fabce1 | 93 | spin_unlock(&ks8695_lock); |
ccb8f430 AV |
94 | } |
95 | ||
96 | /* | |
97 | * Reload the watchdog timer. (ie, pat the watchdog) | |
98 | */ | |
f4fabce1 | 99 | static inline void ks8695_wdt_reload(void) |
ccb8f430 AV |
100 | { |
101 | unsigned long tmcon; | |
102 | ||
f4fabce1 | 103 | spin_lock(&ks8695_lock); |
ccb8f430 AV |
104 | /* disable, then re-enable timer0 */ |
105 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); | |
106 | __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); | |
107 | __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); | |
f4fabce1 | 108 | spin_unlock(&ks8695_lock); |
ccb8f430 AV |
109 | } |
110 | ||
111 | /* | |
112 | * Change the watchdog time interval. | |
113 | */ | |
114 | static int ks8695_wdt_settimeout(int new_time) | |
115 | { | |
116 | /* | |
0a51810a | 117 | * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz |
ccb8f430 AV |
118 | * |
119 | * Since WDV is a 16-bit counter, the maximum period is | |
120 | * 65536 / 0.256 = 256 seconds. | |
121 | */ | |
122 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) | |
123 | return -EINVAL; | |
124 | ||
f4fabce1 AC |
125 | /* Set new watchdog time. It will be used when |
126 | ks8695_wdt_start() is called. */ | |
ccb8f430 AV |
127 | wdt_time = new_time; |
128 | return 0; | |
129 | } | |
130 | ||
131 | /* ......................................................................... */ | |
132 | ||
133 | /* | |
134 | * Watchdog device is opened, and watchdog starts running. | |
135 | */ | |
136 | static int ks8695_wdt_open(struct inode *inode, struct file *file) | |
137 | { | |
138 | if (test_and_set_bit(0, &ks8695wdt_busy)) | |
139 | return -EBUSY; | |
140 | ||
141 | ks8695_wdt_start(); | |
c5bf68fe | 142 | return stream_open(inode, file); |
ccb8f430 AV |
143 | } |
144 | ||
145 | /* | |
146 | * Close the watchdog device. | |
147 | * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also | |
148 | * disabled. | |
149 | */ | |
150 | static int ks8695_wdt_close(struct inode *inode, struct file *file) | |
151 | { | |
f4fabce1 | 152 | /* Disable the watchdog when file is closed */ |
ccb8f430 | 153 | if (!nowayout) |
f4fabce1 | 154 | ks8695_wdt_stop(); |
ccb8f430 AV |
155 | clear_bit(0, &ks8695wdt_busy); |
156 | return 0; | |
157 | } | |
158 | ||
42747d71 | 159 | static const struct watchdog_info ks8695_wdt_info = { |
ccb8f430 AV |
160 | .identity = "ks8695 watchdog", |
161 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
162 | }; | |
163 | ||
164 | /* | |
165 | * Handle commands from user-space. | |
166 | */ | |
f4fabce1 AC |
167 | static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd, |
168 | unsigned long arg) | |
ccb8f430 AV |
169 | { |
170 | void __user *argp = (void __user *)arg; | |
171 | int __user *p = argp; | |
172 | int new_value; | |
173 | ||
f4fabce1 | 174 | switch (cmd) { |
f4fabce1 AC |
175 | case WDIOC_GETSUPPORT: |
176 | return copy_to_user(argp, &ks8695_wdt_info, | |
177 | sizeof(ks8695_wdt_info)) ? -EFAULT : 0; | |
f4fabce1 AC |
178 | case WDIOC_GETSTATUS: |
179 | case WDIOC_GETBOOTSTATUS: | |
180 | return put_user(0, p); | |
181 | case WDIOC_SETOPTIONS: | |
182 | if (get_user(new_value, p)) | |
183 | return -EFAULT; | |
184 | if (new_value & WDIOS_DISABLECARD) | |
185 | ks8695_wdt_stop(); | |
186 | if (new_value & WDIOS_ENABLECARD) | |
ccb8f430 | 187 | ks8695_wdt_start(); |
f4fabce1 | 188 | return 0; |
0c06090c WVS |
189 | case WDIOC_KEEPALIVE: |
190 | ks8695_wdt_reload(); /* pat the watchdog */ | |
191 | return 0; | |
192 | case WDIOC_SETTIMEOUT: | |
193 | if (get_user(new_value, p)) | |
194 | return -EFAULT; | |
195 | if (ks8695_wdt_settimeout(new_value)) | |
196 | return -EINVAL; | |
197 | /* Enable new time value */ | |
198 | ks8695_wdt_start(); | |
199 | /* Return current value */ | |
200 | return put_user(wdt_time, p); | |
201 | case WDIOC_GETTIMEOUT: | |
202 | return put_user(wdt_time, p); | |
f4fabce1 AC |
203 | default: |
204 | return -ENOTTY; | |
ccb8f430 AV |
205 | } |
206 | } | |
207 | ||
208 | /* | |
209 | * Pat the watchdog whenever device is written to. | |
210 | */ | |
f4fabce1 AC |
211 | static ssize_t ks8695_wdt_write(struct file *file, const char *data, |
212 | size_t len, loff_t *ppos) | |
ccb8f430 AV |
213 | { |
214 | ks8695_wdt_reload(); /* pat the watchdog */ | |
215 | return len; | |
216 | } | |
217 | ||
218 | /* ......................................................................... */ | |
219 | ||
220 | static const struct file_operations ks8695wdt_fops = { | |
221 | .owner = THIS_MODULE, | |
222 | .llseek = no_llseek, | |
f4fabce1 | 223 | .unlocked_ioctl = ks8695_wdt_ioctl, |
ccb8f430 AV |
224 | .open = ks8695_wdt_open, |
225 | .release = ks8695_wdt_close, | |
226 | .write = ks8695_wdt_write, | |
227 | }; | |
228 | ||
229 | static struct miscdevice ks8695wdt_miscdev = { | |
230 | .minor = WATCHDOG_MINOR, | |
231 | .name = "watchdog", | |
232 | .fops = &ks8695wdt_fops, | |
233 | }; | |
234 | ||
2d991a16 | 235 | static int ks8695wdt_probe(struct platform_device *pdev) |
ccb8f430 AV |
236 | { |
237 | int res; | |
238 | ||
239 | if (ks8695wdt_miscdev.parent) | |
240 | return -EBUSY; | |
241 | ks8695wdt_miscdev.parent = &pdev->dev; | |
242 | ||
243 | res = misc_register(&ks8695wdt_miscdev); | |
244 | if (res) | |
245 | return res; | |
246 | ||
27c766aa JP |
247 | pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n", |
248 | wdt_time, nowayout ? ", nowayout" : ""); | |
ccb8f430 AV |
249 | return 0; |
250 | } | |
251 | ||
4b12b896 | 252 | static int ks8695wdt_remove(struct platform_device *pdev) |
ccb8f430 | 253 | { |
f368ed60 GKH |
254 | misc_deregister(&ks8695wdt_miscdev); |
255 | ks8695wdt_miscdev.parent = NULL; | |
ccb8f430 | 256 | |
f368ed60 | 257 | return 0; |
ccb8f430 AV |
258 | } |
259 | ||
260 | static void ks8695wdt_shutdown(struct platform_device *pdev) | |
261 | { | |
262 | ks8695_wdt_stop(); | |
263 | } | |
264 | ||
265 | #ifdef CONFIG_PM | |
266 | ||
267 | static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
268 | { | |
269 | ks8695_wdt_stop(); | |
270 | return 0; | |
271 | } | |
272 | ||
273 | static int ks8695wdt_resume(struct platform_device *pdev) | |
274 | { | |
275 | if (ks8695wdt_busy) | |
276 | ks8695_wdt_start(); | |
277 | return 0; | |
278 | } | |
279 | ||
280 | #else | |
281 | #define ks8695wdt_suspend NULL | |
282 | #define ks8695wdt_resume NULL | |
283 | #endif | |
284 | ||
285 | static struct platform_driver ks8695wdt_driver = { | |
286 | .probe = ks8695wdt_probe, | |
82268714 | 287 | .remove = ks8695wdt_remove, |
ccb8f430 AV |
288 | .shutdown = ks8695wdt_shutdown, |
289 | .suspend = ks8695wdt_suspend, | |
290 | .resume = ks8695wdt_resume, | |
291 | .driver = { | |
292 | .name = "ks8695_wdt", | |
ccb8f430 AV |
293 | }, |
294 | }; | |
295 | ||
296 | static int __init ks8695_wdt_init(void) | |
297 | { | |
f4fabce1 AC |
298 | /* Check that the heartbeat value is within range; |
299 | if not reset to the default */ | |
ccb8f430 AV |
300 | if (ks8695_wdt_settimeout(wdt_time)) { |
301 | ks8695_wdt_settimeout(WDT_DEFAULT_TIME); | |
a77dba7e WVS |
302 | pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i" |
303 | ", using %d\n", wdt_time, WDT_MAX_TIME); | |
ccb8f430 | 304 | } |
ccb8f430 AV |
305 | return platform_driver_register(&ks8695wdt_driver); |
306 | } | |
307 | ||
308 | static void __exit ks8695_wdt_exit(void) | |
309 | { | |
310 | platform_driver_unregister(&ks8695wdt_driver); | |
311 | } | |
312 | ||
313 | module_init(ks8695_wdt_init); | |
314 | module_exit(ks8695_wdt_exit); | |
315 | ||
316 | MODULE_AUTHOR("Andrew Victor"); | |
317 | MODULE_DESCRIPTION("Watchdog driver for KS8695"); | |
318 | MODULE_LICENSE("GPL"); | |
f37d193c | 319 | MODULE_ALIAS("platform:ks8695_wdt"); |