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accde168 | 1 | /* |
2 | * Watchdog driver for Freescale STMP37XX/STMP378X | |
3 | * | |
4 | * Author: Vitaly Wool <vital@embeddedalley.com> | |
5 | * | |
6 | * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved. | |
7 | * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. | |
8 | */ | |
9 | #include <linux/init.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/fs.h> | |
12 | #include <linux/miscdevice.h> | |
13 | #include <linux/watchdog.h> | |
14 | #include <linux/platform_device.h> | |
15 | #include <linux/spinlock.h> | |
16 | #include <linux/uaccess.h> | |
17 | ||
18 | #include <mach/platform.h> | |
19 | #include <mach/regs-rtc.h> | |
20 | ||
21 | #define DEFAULT_HEARTBEAT 19 | |
22 | #define MAX_HEARTBEAT (0x10000000 >> 6) | |
23 | ||
24 | /* missing bitmask in headers */ | |
25 | #define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER 0x80000000 | |
26 | ||
27 | #define WDT_IN_USE 0 | |
28 | #define WDT_OK_TO_CLOSE 1 | |
29 | ||
30 | #define WDOG_COUNTER_RATE 1000 /* 1 kHz clock */ | |
31 | ||
32 | static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock); | |
33 | static unsigned long wdt_status; | |
34 | static const int nowayout = WATCHDOG_NOWAYOUT; | |
35 | static int heartbeat = DEFAULT_HEARTBEAT; | |
36 | static unsigned long boot_status; | |
37 | ||
38 | static void wdt_enable(u32 value) | |
39 | { | |
40 | spin_lock(&stmp3xxx_wdt_io_lock); | |
41 | __raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG); | |
42 | stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL); | |
43 | stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER, | |
44 | REGS_RTC_BASE + HW_RTC_PERSISTENT1); | |
45 | spin_unlock(&stmp3xxx_wdt_io_lock); | |
46 | } | |
47 | ||
48 | static void wdt_disable(void) | |
49 | { | |
50 | spin_lock(&stmp3xxx_wdt_io_lock); | |
51 | stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER, | |
52 | REGS_RTC_BASE + HW_RTC_PERSISTENT1); | |
53 | stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL); | |
54 | spin_unlock(&stmp3xxx_wdt_io_lock); | |
55 | } | |
56 | ||
57 | static void wdt_ping(void) | |
58 | { | |
59 | wdt_enable(heartbeat * WDOG_COUNTER_RATE); | |
60 | } | |
61 | ||
62 | static int stmp3xxx_wdt_open(struct inode *inode, struct file *file) | |
63 | { | |
64 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) | |
65 | return -EBUSY; | |
66 | ||
67 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
68 | wdt_ping(); | |
69 | ||
70 | return nonseekable_open(inode, file); | |
71 | } | |
72 | ||
73 | static ssize_t stmp3xxx_wdt_write(struct file *file, const char __user *data, | |
74 | size_t len, loff_t *ppos) | |
75 | { | |
76 | if (len) { | |
77 | if (!nowayout) { | |
78 | size_t i; | |
79 | ||
80 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
81 | ||
82 | for (i = 0; i != len; i++) { | |
83 | char c; | |
84 | ||
85 | if (get_user(c, data + i)) | |
86 | return -EFAULT; | |
87 | if (c == 'V') | |
88 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
89 | } | |
90 | } | |
91 | wdt_ping(); | |
92 | } | |
93 | ||
94 | return len; | |
95 | } | |
96 | ||
42747d71 | 97 | static const struct watchdog_info ident = { |
accde168 | 98 | .options = WDIOF_CARDRESET | |
99 | WDIOF_MAGICCLOSE | | |
100 | WDIOF_SETTIMEOUT | | |
101 | WDIOF_KEEPALIVEPING, | |
102 | .identity = "STMP3XXX Watchdog", | |
103 | }; | |
104 | ||
105 | static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd, | |
106 | unsigned long arg) | |
107 | { | |
108 | void __user *argp = (void __user *)arg; | |
109 | int __user *p = argp; | |
110 | int new_heartbeat, opts; | |
111 | int ret = -ENOTTY; | |
112 | ||
113 | switch (cmd) { | |
114 | case WDIOC_GETSUPPORT: | |
115 | ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
116 | break; | |
117 | ||
118 | case WDIOC_GETSTATUS: | |
119 | ret = put_user(0, p); | |
120 | break; | |
121 | ||
122 | case WDIOC_GETBOOTSTATUS: | |
123 | ret = put_user(boot_status, p); | |
124 | break; | |
125 | ||
126 | case WDIOC_SETOPTIONS: | |
127 | if (get_user(opts, p)) { | |
128 | ret = -EFAULT; | |
129 | break; | |
130 | } | |
131 | if (opts & WDIOS_DISABLECARD) | |
132 | wdt_disable(); | |
133 | else if (opts & WDIOS_ENABLECARD) | |
134 | wdt_ping(); | |
135 | else { | |
136 | pr_debug("%s: unknown option 0x%x\n", __func__, opts); | |
137 | ret = -EINVAL; | |
138 | break; | |
139 | } | |
140 | ret = 0; | |
141 | break; | |
142 | ||
143 | case WDIOC_KEEPALIVE: | |
144 | wdt_ping(); | |
145 | ret = 0; | |
146 | break; | |
147 | ||
148 | case WDIOC_SETTIMEOUT: | |
149 | if (get_user(new_heartbeat, p)) { | |
150 | ret = -EFAULT; | |
151 | break; | |
152 | } | |
153 | if (new_heartbeat <= 0 || new_heartbeat > MAX_HEARTBEAT) { | |
154 | ret = -EINVAL; | |
155 | break; | |
156 | } | |
157 | ||
158 | heartbeat = new_heartbeat; | |
159 | wdt_ping(); | |
160 | /* Fall through */ | |
161 | ||
162 | case WDIOC_GETTIMEOUT: | |
163 | ret = put_user(heartbeat, p); | |
164 | break; | |
165 | } | |
166 | return ret; | |
167 | } | |
168 | ||
169 | static int stmp3xxx_wdt_release(struct inode *inode, struct file *file) | |
170 | { | |
171 | int ret = 0; | |
172 | ||
173 | if (!nowayout) { | |
174 | if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { | |
175 | wdt_ping(); | |
176 | pr_debug("%s: Device closed unexpectdly\n", __func__); | |
177 | ret = -EINVAL; | |
178 | } else { | |
179 | wdt_disable(); | |
180 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
181 | } | |
182 | } | |
183 | clear_bit(WDT_IN_USE, &wdt_status); | |
184 | ||
185 | return ret; | |
186 | } | |
187 | ||
188 | static const struct file_operations stmp3xxx_wdt_fops = { | |
189 | .owner = THIS_MODULE, | |
190 | .llseek = no_llseek, | |
191 | .write = stmp3xxx_wdt_write, | |
192 | .unlocked_ioctl = stmp3xxx_wdt_ioctl, | |
193 | .open = stmp3xxx_wdt_open, | |
194 | .release = stmp3xxx_wdt_release, | |
195 | }; | |
196 | ||
197 | static struct miscdevice stmp3xxx_wdt_miscdev = { | |
198 | .minor = WATCHDOG_MINOR, | |
199 | .name = "watchdog", | |
200 | .fops = &stmp3xxx_wdt_fops, | |
201 | }; | |
202 | ||
203 | static int __devinit stmp3xxx_wdt_probe(struct platform_device *pdev) | |
204 | { | |
205 | int ret = 0; | |
206 | ||
207 | if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) | |
208 | heartbeat = DEFAULT_HEARTBEAT; | |
209 | ||
210 | boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) & | |
211 | BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER; | |
212 | boot_status = !!boot_status; | |
213 | stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER, | |
214 | REGS_RTC_BASE + HW_RTC_PERSISTENT1); | |
215 | wdt_disable(); /* disable for now */ | |
216 | ||
217 | ret = misc_register(&stmp3xxx_wdt_miscdev); | |
218 | if (ret < 0) { | |
219 | dev_err(&pdev->dev, "cannot register misc device\n"); | |
220 | return ret; | |
221 | } | |
222 | ||
223 | printk(KERN_INFO "stmp3xxx watchdog: initialized, heartbeat %d sec\n", | |
224 | heartbeat); | |
225 | ||
226 | return ret; | |
227 | } | |
228 | ||
229 | static int __devexit stmp3xxx_wdt_remove(struct platform_device *pdev) | |
230 | { | |
231 | misc_deregister(&stmp3xxx_wdt_miscdev); | |
232 | return 0; | |
233 | } | |
234 | ||
235 | #ifdef CONFIG_PM | |
236 | static int wdt_suspended; | |
237 | static u32 wdt_saved_time; | |
238 | ||
239 | static int stmp3xxx_wdt_suspend(struct platform_device *pdev, | |
240 | pm_message_t state) | |
241 | { | |
242 | if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) & | |
243 | BM_RTC_CTRL_WATCHDOGEN) { | |
244 | wdt_suspended = 1; | |
245 | wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG); | |
246 | wdt_disable(); | |
247 | } | |
248 | return 0; | |
249 | } | |
250 | ||
251 | static int stmp3xxx_wdt_resume(struct platform_device *pdev) | |
252 | { | |
253 | if (wdt_suspended) { | |
254 | wdt_enable(wdt_saved_time); | |
255 | wdt_suspended = 0; | |
256 | } | |
257 | return 0; | |
258 | } | |
259 | #else | |
260 | #define stmp3xxx_wdt_suspend NULL | |
261 | #define stmp3xxx_wdt_resume NULL | |
262 | #endif | |
263 | ||
264 | static struct platform_driver platform_wdt_driver = { | |
265 | .driver = { | |
266 | .name = "stmp3xxx_wdt", | |
267 | }, | |
268 | .probe = stmp3xxx_wdt_probe, | |
269 | .remove = __devexit_p(stmp3xxx_wdt_remove), | |
270 | .suspend = stmp3xxx_wdt_suspend, | |
271 | .resume = stmp3xxx_wdt_resume, | |
272 | }; | |
273 | ||
274 | static int __init stmp3xxx_wdt_init(void) | |
275 | { | |
276 | return platform_driver_register(&platform_wdt_driver); | |
277 | } | |
278 | ||
279 | static void __exit stmp3xxx_wdt_exit(void) | |
280 | { | |
281 | return platform_driver_unregister(&platform_wdt_driver); | |
282 | } | |
283 | ||
284 | module_init(stmp3xxx_wdt_init); | |
285 | module_exit(stmp3xxx_wdt_exit); | |
286 | ||
287 | MODULE_DESCRIPTION("STMP3XXX Watchdog Driver"); | |
288 | MODULE_LICENSE("GPL"); | |
289 | ||
290 | module_param(heartbeat, int, 0); | |
291 | MODULE_PARM_DESC(heartbeat, | |
292 | "Watchdog heartbeat period in seconds from 1 to " | |
293 | __MODULE_STRING(MAX_HEARTBEAT) ", default " | |
294 | __MODULE_STRING(DEFAULT_HEARTBEAT)); | |
295 | ||
296 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |