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19
20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22#include <linux/bitops.h>
23#include <linux/delay.h>
24#include <linux/errno.h>
25#include <linux/fs.h>
26#include <linux/io.h>
27#include <linux/kernel.h>
28#include <linux/miscdevice.h>
29#include <linux/module.h>
30#include <linux/moduleparam.h>
31#include <linux/platform_device.h>
32#include <linux/types.h>
33#include <linux/watchdog.h>
34#include <linux/clk.h>
35#include <linux/err.h>
36#include <linux/of.h>
37#include <linux/of_platform.h>
38#include <linux/uaccess.h>
39
40#define DRIVER_NAME "ath79-wdt"
41
42#define WDT_TIMEOUT 15
43
44#define WDOG_REG_CTRL 0x00
45#define WDOG_REG_TIMER 0x04
46
47#define WDOG_CTRL_LAST_RESET BIT(31)
48#define WDOG_CTRL_ACTION_MASK 3
49#define WDOG_CTRL_ACTION_NONE 0
50#define WDOG_CTRL_ACTION_GPI 1
51#define WDOG_CTRL_ACTION_NMI 2
52#define WDOG_CTRL_ACTION_FCR 3
53
54static bool nowayout = WATCHDOG_NOWAYOUT;
55module_param(nowayout, bool, 0);
56MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
57 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
58
59static int timeout = WDT_TIMEOUT;
60module_param(timeout, int, 0);
61MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
62 "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");
63
64static unsigned long wdt_flags;
65
66#define WDT_FLAGS_BUSY 0
67#define WDT_FLAGS_EXPECT_CLOSE 1
68
69static struct clk *wdt_clk;
70static unsigned long wdt_freq;
71static int boot_status;
72static int max_timeout;
73static void __iomem *wdt_base;
74
75static inline void ath79_wdt_wr(unsigned reg, u32 val)
76{
77 iowrite32(val, wdt_base + reg);
78}
79
80static inline u32 ath79_wdt_rr(unsigned reg)
81{
82 return ioread32(wdt_base + reg);
83}
84
85static inline void ath79_wdt_keepalive(void)
86{
87 ath79_wdt_wr(WDOG_REG_TIMER, wdt_freq * timeout);
88
89 ath79_wdt_rr(WDOG_REG_TIMER);
90}
91
92static inline void ath79_wdt_enable(void)
93{
94 ath79_wdt_keepalive();
95
96
97
98
99
100
101
102 udelay(2);
103
104 ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_FCR);
105
106 ath79_wdt_rr(WDOG_REG_CTRL);
107}
108
109static inline void ath79_wdt_disable(void)
110{
111 ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_NONE);
112
113 ath79_wdt_rr(WDOG_REG_CTRL);
114}
115
116static int ath79_wdt_set_timeout(int val)
117{
118 if (val < 1 || val > max_timeout)
119 return -EINVAL;
120
121 timeout = val;
122 ath79_wdt_keepalive();
123
124 return 0;
125}
126
127static int ath79_wdt_open(struct inode *inode, struct file *file)
128{
129 if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
130 return -EBUSY;
131
132 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
133 ath79_wdt_enable();
134
135 return nonseekable_open(inode, file);
136}
137
138static int ath79_wdt_release(struct inode *inode, struct file *file)
139{
140 if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
141 ath79_wdt_disable();
142 else {
143 pr_crit("device closed unexpectedly, watchdog timer will not stop!\n");
144 ath79_wdt_keepalive();
145 }
146
147 clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
148 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
149
150 return 0;
151}
152
153static ssize_t ath79_wdt_write(struct file *file, const char *data,
154 size_t len, loff_t *ppos)
155{
156 if (len) {
157 if (!nowayout) {
158 size_t i;
159
160 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
161
162 for (i = 0; i != len; i++) {
163 char c;
164
165 if (get_user(c, data + i))
166 return -EFAULT;
167
168 if (c == 'V')
169 set_bit(WDT_FLAGS_EXPECT_CLOSE,
170 &wdt_flags);
171 }
172 }
173
174 ath79_wdt_keepalive();
175 }
176
177 return len;
178}
179
180static const struct watchdog_info ath79_wdt_info = {
181 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
182 WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
183 .firmware_version = 0,
184 .identity = "ATH79 watchdog",
185};
186
187static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
188 unsigned long arg)
189{
190 void __user *argp = (void __user *)arg;
191 int __user *p = argp;
192 int err;
193 int t;
194
195 switch (cmd) {
196 case WDIOC_GETSUPPORT:
197 err = copy_to_user(argp, &ath79_wdt_info,
198 sizeof(ath79_wdt_info)) ? -EFAULT : 0;
199 break;
200
201 case WDIOC_GETSTATUS:
202 err = put_user(0, p);
203 break;
204
205 case WDIOC_GETBOOTSTATUS:
206 err = put_user(boot_status, p);
207 break;
208
209 case WDIOC_KEEPALIVE:
210 ath79_wdt_keepalive();
211 err = 0;
212 break;
213
214 case WDIOC_SETTIMEOUT:
215 err = get_user(t, p);
216 if (err)
217 break;
218
219 err = ath79_wdt_set_timeout(t);
220 if (err)
221 break;
222
223
224 case WDIOC_GETTIMEOUT:
225 err = put_user(timeout, p);
226 break;
227
228 default:
229 err = -ENOTTY;
230 break;
231 }
232
233 return err;
234}
235
236static const struct file_operations ath79_wdt_fops = {
237 .owner = THIS_MODULE,
238 .llseek = no_llseek,
239 .write = ath79_wdt_write,
240 .unlocked_ioctl = ath79_wdt_ioctl,
241 .open = ath79_wdt_open,
242 .release = ath79_wdt_release,
243};
244
245static struct miscdevice ath79_wdt_miscdev = {
246 .minor = WATCHDOG_MINOR,
247 .name = "watchdog",
248 .fops = &ath79_wdt_fops,
249};
250
251static int ath79_wdt_probe(struct platform_device *pdev)
252{
253 struct resource *res;
254 u32 ctrl;
255 int err;
256
257 if (wdt_base)
258 return -EBUSY;
259
260 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
261 wdt_base = devm_ioremap_resource(&pdev->dev, res);
262 if (IS_ERR(wdt_base))
263 return PTR_ERR(wdt_base);
264
265 wdt_clk = devm_clk_get(&pdev->dev, "wdt");
266 if (IS_ERR(wdt_clk))
267 return PTR_ERR(wdt_clk);
268
269 err = clk_prepare_enable(wdt_clk);
270 if (err)
271 return err;
272
273 wdt_freq = clk_get_rate(wdt_clk);
274 if (!wdt_freq) {
275 err = -EINVAL;
276 goto err_clk_disable;
277 }
278
279 max_timeout = (0xfffffffful / wdt_freq);
280 if (timeout < 1 || timeout > max_timeout) {
281 timeout = max_timeout;
282 dev_info(&pdev->dev,
283 "timeout value must be 0 < timeout < %d, using %d\n",
284 max_timeout, timeout);
285 }
286
287 ctrl = ath79_wdt_rr(WDOG_REG_CTRL);
288 boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
289
290 err = misc_register(&ath79_wdt_miscdev);
291 if (err) {
292 dev_err(&pdev->dev,
293 "unable to register misc device, err=%d\n", err);
294 goto err_clk_disable;
295 }
296
297 return 0;
298
299err_clk_disable:
300 clk_disable_unprepare(wdt_clk);
301 return err;
302}
303
304static int ath79_wdt_remove(struct platform_device *pdev)
305{
306 misc_deregister(&ath79_wdt_miscdev);
307 clk_disable_unprepare(wdt_clk);
308 return 0;
309}
310
311static void ath97_wdt_shutdown(struct platform_device *pdev)
312{
313 ath79_wdt_disable();
314}
315
316#ifdef CONFIG_OF
317static const struct of_device_id ath79_wdt_match[] = {
318 { .compatible = "qca,ar7130-wdt" },
319 {},
320};
321MODULE_DEVICE_TABLE(of, ath79_wdt_match);
322#endif
323
324static struct platform_driver ath79_wdt_driver = {
325 .probe = ath79_wdt_probe,
326 .remove = ath79_wdt_remove,
327 .shutdown = ath97_wdt_shutdown,
328 .driver = {
329 .name = DRIVER_NAME,
330 .of_match_table = of_match_ptr(ath79_wdt_match),
331 },
332};
333
334module_platform_driver(ath79_wdt_driver);
335
336MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
337MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
338MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
339MODULE_LICENSE("GPL v2");
340MODULE_ALIAS("platform:" DRIVER_NAME);
341
