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