1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23#include <linux/init.h>
24#include <linux/kernel.h>
25#include <linux/miscdevice.h>
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/platform_device.h>
29#include <linux/watchdog.h>
30#include <linux/clk.h>
31#include <linux/fs.h>
32#include <linux/io.h>
33#include <linux/uaccess.h>
34#include <linux/timer.h>
35#include <linux/jiffies.h>
36
37#define DRIVER_NAME "imx2-wdt"
38
39#define IMX2_WDT_WCR 0x00
40#define IMX2_WDT_WCR_WT (0xFF << 8)
41#define IMX2_WDT_WCR_WRE (1 << 3)
42#define IMX2_WDT_WCR_WDE (1 << 2)
43
44#define IMX2_WDT_WSR 0x02
45#define IMX2_WDT_SEQ1 0x5555
46#define IMX2_WDT_SEQ2 0xAAAA
47
48#define IMX2_WDT_WRSR 0x04
49#define IMX2_WDT_WRSR_TOUT (1 << 1)
50
51#define IMX2_WDT_MAX_TIME 128
52#define IMX2_WDT_DEFAULT_TIME 60
53
54#define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8)
55
56#define IMX2_WDT_STATUS_OPEN 0
57#define IMX2_WDT_STATUS_STARTED 1
58#define IMX2_WDT_EXPECT_CLOSE 2
59
60static struct {
61 struct clk *clk;
62 void __iomem *base;
63 unsigned timeout;
64 unsigned long status;
65 struct timer_list timer;
66} imx2_wdt;
67
68static struct miscdevice imx2_wdt_miscdev;
69
70static bool nowayout = WATCHDOG_NOWAYOUT;
71module_param(nowayout, bool, 0);
72MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
73 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
74
75
76static unsigned timeout = IMX2_WDT_DEFAULT_TIME;
77module_param(timeout, uint, 0);
78MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
79 __MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")");
80
81static const struct watchdog_info imx2_wdt_info = {
82 .identity = "imx2+ watchdog",
83 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
84};
85
86static inline void imx2_wdt_setup(void)
87{
88 u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR);
89
90
91 val &= ~IMX2_WDT_WCR_WT;
92
93 val &= ~IMX2_WDT_WCR_WRE;
94
95 val &= ~IMX2_WDT_WCR_WDE;
96
97 val |= WDOG_SEC_TO_COUNT(imx2_wdt.timeout);
98
99 __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
100
101
102 val |= IMX2_WDT_WCR_WDE;
103 __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
104}
105
106static inline void imx2_wdt_ping(void)
107{
108 __raw_writew(IMX2_WDT_SEQ1, imx2_wdt.base + IMX2_WDT_WSR);
109 __raw_writew(IMX2_WDT_SEQ2, imx2_wdt.base + IMX2_WDT_WSR);
110}
111
112static void imx2_wdt_timer_ping(unsigned long arg)
113{
114
115 imx2_wdt_ping();
116 mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2);
117}
118
119static void imx2_wdt_start(void)
120{
121 if (!test_and_set_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
122
123 clk_prepare_enable(imx2_wdt.clk);
124
125 imx2_wdt_setup();
126 } else
127 del_timer_sync(&imx2_wdt.timer);
128
129
130 imx2_wdt_ping();
131}
132
133static void imx2_wdt_stop(void)
134{
135
136
137 imx2_wdt_timer_ping(0);
138}
139
140static void imx2_wdt_set_timeout(int new_timeout)
141{
142 u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR);
143
144
145 val &= ~IMX2_WDT_WCR_WT;
146 val |= WDOG_SEC_TO_COUNT(new_timeout);
147 __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
148}
149
150static int imx2_wdt_open(struct inode *inode, struct file *file)
151{
152 if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status))
153 return -EBUSY;
154
155 imx2_wdt_start();
156 return nonseekable_open(inode, file);
157}
158
159static int imx2_wdt_close(struct inode *inode, struct file *file)
160{
161 if (test_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status) && !nowayout)
162 imx2_wdt_stop();
163 else {
164 dev_crit(imx2_wdt_miscdev.parent,
165 "Unexpected close: Expect reboot!\n");
166 imx2_wdt_ping();
167 }
168
169 clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
170 clear_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status);
171 return 0;
172}
173
174static long imx2_wdt_ioctl(struct file *file, unsigned int cmd,
175 unsigned long arg)
176{
177 void __user *argp = (void __user *)arg;
178 int __user *p = argp;
179 int new_value;
180 u16 val;
181
182 switch (cmd) {
183 case WDIOC_GETSUPPORT:
184 return copy_to_user(argp, &imx2_wdt_info,
185 sizeof(struct watchdog_info)) ? -EFAULT : 0;
186
187 case WDIOC_GETSTATUS:
188 return put_user(0, p);
189
190 case WDIOC_GETBOOTSTATUS:
191 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WRSR);
192 new_value = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
193 return put_user(new_value, p);
194
195 case WDIOC_KEEPALIVE:
196 imx2_wdt_ping();
197 return 0;
198
199 case WDIOC_SETTIMEOUT:
200 if (get_user(new_value, p))
201 return -EFAULT;
202 if ((new_value < 1) || (new_value > IMX2_WDT_MAX_TIME))
203 return -EINVAL;
204 imx2_wdt_set_timeout(new_value);
205 imx2_wdt.timeout = new_value;
206 imx2_wdt_ping();
207
208
209 case WDIOC_GETTIMEOUT:
210 return put_user(imx2_wdt.timeout, p);
211
212 default:
213 return -ENOTTY;
214 }
215}
216
217static ssize_t imx2_wdt_write(struct file *file, const char __user *data,
218 size_t len, loff_t *ppos)
219{
220 size_t i;
221 char c;
222
223 if (len == 0)
224 return 0;
225
226 clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
227
228 for (i = 0; i != len; i++) {
229 if (get_user(c, data + i))
230 return -EFAULT;
231 if (c == 'V')
232 set_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
233 }
234
235 imx2_wdt_ping();
236 return len;
237}
238
239static const struct file_operations imx2_wdt_fops = {
240 .owner = THIS_MODULE,
241 .llseek = no_llseek,
242 .unlocked_ioctl = imx2_wdt_ioctl,
243 .open = imx2_wdt_open,
244 .release = imx2_wdt_close,
245 .write = imx2_wdt_write,
246};
247
248static struct miscdevice imx2_wdt_miscdev = {
249 .minor = WATCHDOG_MINOR,
250 .name = "watchdog",
251 .fops = &imx2_wdt_fops,
252};
253
254static int __init imx2_wdt_probe(struct platform_device *pdev)
255{
256 int ret;
257 struct resource *res;
258
259 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
260 imx2_wdt.base = devm_ioremap_resource(&pdev->dev, res);
261 if (IS_ERR(imx2_wdt.base))
262 return PTR_ERR(imx2_wdt.base);
263
264 imx2_wdt.clk = devm_clk_get(&pdev->dev, NULL);
265 if (IS_ERR(imx2_wdt.clk)) {
266 dev_err(&pdev->dev, "can't get Watchdog clock\n");
267 return PTR_ERR(imx2_wdt.clk);
268 }
269
270 imx2_wdt.timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
271 if (imx2_wdt.timeout != timeout)
272 dev_warn(&pdev->dev, "Initial timeout out of range! "
273 "Clamped from %u to %u\n", timeout, imx2_wdt.timeout);
274
275 setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0);
276
277 imx2_wdt_miscdev.parent = &pdev->dev;
278 ret = misc_register(&imx2_wdt_miscdev);
279 if (ret)
280 goto fail;
281
282 dev_info(&pdev->dev,
283 "IMX2+ Watchdog Timer enabled. timeout=%ds (nowayout=%d)\n",
284 imx2_wdt.timeout, nowayout);
285 return 0;
286
287fail:
288 imx2_wdt_miscdev.parent = NULL;
289 return ret;
290}
291
292static int __exit imx2_wdt_remove(struct platform_device *pdev)
293{
294 misc_deregister(&imx2_wdt_miscdev);
295
296 if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
297 del_timer_sync(&imx2_wdt.timer);
298
299 dev_crit(imx2_wdt_miscdev.parent,
300 "Device removed: Expect reboot!\n");
301 }
302
303 imx2_wdt_miscdev.parent = NULL;
304 return 0;
305}
306
307static void imx2_wdt_shutdown(struct platform_device *pdev)
308{
309 if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
310
311
312 del_timer_sync(&imx2_wdt.timer);
313 imx2_wdt_set_timeout(IMX2_WDT_MAX_TIME);
314 imx2_wdt_ping();
315
316 dev_crit(imx2_wdt_miscdev.parent,
317 "Device shutdown: Expect reboot!\n");
318 }
319}
320
321static const struct of_device_id imx2_wdt_dt_ids[] = {
322 { .compatible = "fsl,imx21-wdt", },
323 { }
324};
325
326static struct platform_driver imx2_wdt_driver = {
327 .remove = __exit_p(imx2_wdt_remove),
328 .shutdown = imx2_wdt_shutdown,
329 .driver = {
330 .name = DRIVER_NAME,
331 .owner = THIS_MODULE,
332 .of_match_table = imx2_wdt_dt_ids,
333 },
334};
335
336module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe);
337
338MODULE_AUTHOR("Wolfram Sang");
339MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
340MODULE_LICENSE("GPL v2");
341MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
342MODULE_ALIAS("platform:" DRIVER_NAME);
343
