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b886d83c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
0400e313 WZ |
2 | /* |
3 | * Copyright (c) 2009 Nuvoton technology corporation. | |
4 | * | |
5 | * Wan ZongShun <mcuos.com@gmail.com> | |
0400e313 WZ |
6 | */ |
7 | ||
8 | #include <linux/bitops.h> | |
9 | #include <linux/errno.h> | |
10 | #include <linux/fs.h> | |
0400e313 WZ |
11 | #include <linux/io.h> |
12 | #include <linux/clk.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/miscdevice.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/moduleparam.h> | |
17 | #include <linux/platform_device.h> | |
5a0e3ad6 | 18 | #include <linux/slab.h> |
0400e313 WZ |
19 | #include <linux/interrupt.h> |
20 | #include <linux/types.h> | |
21 | #include <linux/watchdog.h> | |
22 | #include <linux/uaccess.h> | |
23 | ||
24 | #define REG_WTCR 0x1c | |
25 | #define WTCLK (0x01 << 10) | |
26 | #define WTE (0x01 << 7) /*wdt enable*/ | |
27 | #define WTIS (0x03 << 4) | |
28 | #define WTIF (0x01 << 3) | |
29 | #define WTRF (0x01 << 2) | |
30 | #define WTRE (0x01 << 1) | |
31 | #define WTR (0x01 << 0) | |
32 | /* | |
33 | * The watchdog time interval can be calculated via following formula: | |
34 | * WTIS real time interval (formula) | |
35 | * 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds | |
36 | * 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds | |
37 | * 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds | |
38 | * 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds | |
39 | * | |
40 | * The external crystal freq is 15Mhz in the nuc900 evaluation board. | |
41 | * So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds, | |
42 | * 0x03 = +- 16.92 seconds.. | |
43 | */ | |
44 | #define WDT_HW_TIMEOUT 0x02 | |
45 | #define WDT_TIMEOUT (HZ/2) | |
46 | #define WDT_HEARTBEAT 15 | |
47 | ||
48 | static int heartbeat = WDT_HEARTBEAT; | |
49 | module_param(heartbeat, int, 0); | |
50 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. " | |
51 | "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")"); | |
52 | ||
86a1e189 WVS |
53 | static bool nowayout = WATCHDOG_NOWAYOUT; |
54 | module_param(nowayout, bool, 0); | |
0400e313 WZ |
55 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " |
56 | "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
57 | ||
58 | struct nuc900_wdt { | |
0400e313 WZ |
59 | struct clk *wdt_clock; |
60 | struct platform_device *pdev; | |
61 | void __iomem *wdt_base; | |
62 | char expect_close; | |
63 | struct timer_list timer; | |
64 | spinlock_t wdt_lock; | |
65 | unsigned long next_heartbeat; | |
66 | }; | |
67 | ||
68 | static unsigned long nuc900wdt_busy; | |
e352829a | 69 | static struct nuc900_wdt *nuc900_wdt; |
0400e313 WZ |
70 | |
71 | static inline void nuc900_wdt_keepalive(void) | |
72 | { | |
73 | unsigned int val; | |
74 | ||
75 | spin_lock(&nuc900_wdt->wdt_lock); | |
76 | ||
77 | val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); | |
78 | val |= (WTR | WTIF); | |
79 | __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); | |
80 | ||
81 | spin_unlock(&nuc900_wdt->wdt_lock); | |
82 | } | |
83 | ||
84 | static inline void nuc900_wdt_start(void) | |
85 | { | |
86 | unsigned int val; | |
87 | ||
88 | spin_lock(&nuc900_wdt->wdt_lock); | |
89 | ||
90 | val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); | |
91 | val |= (WTRE | WTE | WTR | WTCLK | WTIF); | |
92 | val &= ~WTIS; | |
93 | val |= (WDT_HW_TIMEOUT << 0x04); | |
94 | __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); | |
95 | ||
96 | spin_unlock(&nuc900_wdt->wdt_lock); | |
97 | ||
98 | nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; | |
99 | mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); | |
100 | } | |
101 | ||
102 | static inline void nuc900_wdt_stop(void) | |
103 | { | |
104 | unsigned int val; | |
105 | ||
106 | del_timer(&nuc900_wdt->timer); | |
107 | ||
108 | spin_lock(&nuc900_wdt->wdt_lock); | |
109 | ||
110 | val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); | |
111 | val &= ~WTE; | |
112 | __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); | |
113 | ||
114 | spin_unlock(&nuc900_wdt->wdt_lock); | |
115 | } | |
116 | ||
117 | static inline void nuc900_wdt_ping(void) | |
118 | { | |
119 | nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; | |
120 | } | |
121 | ||
122 | static int nuc900_wdt_open(struct inode *inode, struct file *file) | |
123 | { | |
124 | ||
125 | if (test_and_set_bit(0, &nuc900wdt_busy)) | |
126 | return -EBUSY; | |
127 | ||
128 | nuc900_wdt_start(); | |
129 | ||
c5bf68fe | 130 | return stream_open(inode, file); |
0400e313 WZ |
131 | } |
132 | ||
133 | static int nuc900_wdt_close(struct inode *inode, struct file *file) | |
134 | { | |
135 | if (nuc900_wdt->expect_close == 42) | |
136 | nuc900_wdt_stop(); | |
137 | else { | |
138 | dev_crit(&nuc900_wdt->pdev->dev, | |
139 | "Unexpected close, not stopping watchdog!\n"); | |
140 | nuc900_wdt_ping(); | |
141 | } | |
142 | ||
143 | nuc900_wdt->expect_close = 0; | |
144 | clear_bit(0, &nuc900wdt_busy); | |
145 | return 0; | |
146 | } | |
147 | ||
148 | static const struct watchdog_info nuc900_wdt_info = { | |
149 | .identity = "nuc900 watchdog", | |
150 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
151 | WDIOF_MAGICCLOSE, | |
152 | }; | |
153 | ||
154 | static long nuc900_wdt_ioctl(struct file *file, | |
155 | unsigned int cmd, unsigned long arg) | |
156 | { | |
157 | void __user *argp = (void __user *)arg; | |
158 | int __user *p = argp; | |
159 | int new_value; | |
160 | ||
161 | switch (cmd) { | |
162 | case WDIOC_GETSUPPORT: | |
163 | return copy_to_user(argp, &nuc900_wdt_info, | |
164 | sizeof(nuc900_wdt_info)) ? -EFAULT : 0; | |
165 | case WDIOC_GETSTATUS: | |
166 | case WDIOC_GETBOOTSTATUS: | |
167 | return put_user(0, p); | |
168 | ||
169 | case WDIOC_KEEPALIVE: | |
170 | nuc900_wdt_ping(); | |
171 | return 0; | |
172 | ||
173 | case WDIOC_SETTIMEOUT: | |
174 | if (get_user(new_value, p)) | |
175 | return -EFAULT; | |
176 | ||
177 | heartbeat = new_value; | |
178 | nuc900_wdt_ping(); | |
179 | ||
180 | return put_user(new_value, p); | |
181 | case WDIOC_GETTIMEOUT: | |
182 | return put_user(heartbeat, p); | |
183 | default: | |
184 | return -ENOTTY; | |
185 | } | |
186 | } | |
187 | ||
188 | static ssize_t nuc900_wdt_write(struct file *file, const char __user *data, | |
189 | size_t len, loff_t *ppos) | |
190 | { | |
191 | if (!len) | |
192 | return 0; | |
193 | ||
194 | /* Scan for magic character */ | |
195 | if (!nowayout) { | |
196 | size_t i; | |
197 | ||
198 | nuc900_wdt->expect_close = 0; | |
199 | ||
200 | for (i = 0; i < len; i++) { | |
201 | char c; | |
202 | if (get_user(c, data + i)) | |
203 | return -EFAULT; | |
204 | if (c == 'V') { | |
205 | nuc900_wdt->expect_close = 42; | |
206 | break; | |
207 | } | |
208 | } | |
209 | } | |
210 | ||
211 | nuc900_wdt_ping(); | |
212 | return len; | |
213 | } | |
214 | ||
e99e88a9 | 215 | static void nuc900_wdt_timer_ping(struct timer_list *unused) |
0400e313 WZ |
216 | { |
217 | if (time_before(jiffies, nuc900_wdt->next_heartbeat)) { | |
218 | nuc900_wdt_keepalive(); | |
219 | mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); | |
220 | } else | |
221 | dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n"); | |
222 | } | |
223 | ||
224 | static const struct file_operations nuc900wdt_fops = { | |
225 | .owner = THIS_MODULE, | |
226 | .llseek = no_llseek, | |
227 | .unlocked_ioctl = nuc900_wdt_ioctl, | |
228 | .open = nuc900_wdt_open, | |
229 | .release = nuc900_wdt_close, | |
230 | .write = nuc900_wdt_write, | |
231 | }; | |
232 | ||
233 | static struct miscdevice nuc900wdt_miscdev = { | |
234 | .minor = WATCHDOG_MINOR, | |
235 | .name = "watchdog", | |
236 | .fops = &nuc900wdt_fops, | |
237 | }; | |
238 | ||
2d991a16 | 239 | static int nuc900wdt_probe(struct platform_device *pdev) |
0400e313 WZ |
240 | { |
241 | int ret = 0; | |
242 | ||
3666eb02 JH |
243 | nuc900_wdt = devm_kzalloc(&pdev->dev, sizeof(*nuc900_wdt), |
244 | GFP_KERNEL); | |
0400e313 WZ |
245 | if (!nuc900_wdt) |
246 | return -ENOMEM; | |
247 | ||
248 | nuc900_wdt->pdev = pdev; | |
249 | ||
250 | spin_lock_init(&nuc900_wdt->wdt_lock); | |
251 | ||
0f0a6a28 | 252 | nuc900_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0); |
3666eb02 JH |
253 | if (IS_ERR(nuc900_wdt->wdt_base)) |
254 | return PTR_ERR(nuc900_wdt->wdt_base); | |
0400e313 | 255 | |
3666eb02 | 256 | nuc900_wdt->wdt_clock = devm_clk_get(&pdev->dev, NULL); |
0400e313 WZ |
257 | if (IS_ERR(nuc900_wdt->wdt_clock)) { |
258 | dev_err(&pdev->dev, "failed to find watchdog clock source\n"); | |
3666eb02 | 259 | return PTR_ERR(nuc900_wdt->wdt_clock); |
0400e313 WZ |
260 | } |
261 | ||
262 | clk_enable(nuc900_wdt->wdt_clock); | |
263 | ||
e99e88a9 | 264 | timer_setup(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0); |
0400e313 | 265 | |
2865e770 AL |
266 | ret = misc_register(&nuc900wdt_miscdev); |
267 | if (ret) { | |
0400e313 WZ |
268 | dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n", |
269 | WATCHDOG_MINOR, ret); | |
270 | goto err_clk; | |
271 | } | |
272 | ||
273 | return 0; | |
274 | ||
275 | err_clk: | |
276 | clk_disable(nuc900_wdt->wdt_clock); | |
0400e313 WZ |
277 | return ret; |
278 | } | |
279 | ||
4b12b896 | 280 | static int nuc900wdt_remove(struct platform_device *pdev) |
0400e313 WZ |
281 | { |
282 | misc_deregister(&nuc900wdt_miscdev); | |
283 | ||
284 | clk_disable(nuc900_wdt->wdt_clock); | |
0400e313 WZ |
285 | |
286 | return 0; | |
287 | } | |
288 | ||
289 | static struct platform_driver nuc900wdt_driver = { | |
290 | .probe = nuc900wdt_probe, | |
82268714 | 291 | .remove = nuc900wdt_remove, |
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292 | .driver = { |
293 | .name = "nuc900-wdt", | |
0400e313 WZ |
294 | }, |
295 | }; | |
296 | ||
b8ec6118 | 297 | module_platform_driver(nuc900wdt_driver); |
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298 | |
299 | MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>"); | |
300 | MODULE_DESCRIPTION("Watchdog driver for NUC900"); | |
301 | MODULE_LICENSE("GPL"); | |
0400e313 | 302 | MODULE_ALIAS("platform:nuc900-wdt"); |