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