1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Watchdog for the 7101 PMU version found in the ALi M1535 chipsets |
4 | */ |
5 | |
6 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
7 | |
8 | #include <linux/module.h> |
9 | #include <linux/moduleparam.h> |
10 | #include <linux/types.h> |
11 | #include <linux/miscdevice.h> |
12 | #include <linux/watchdog.h> |
13 | #include <linux/ioport.h> |
14 | #include <linux/notifier.h> |
15 | #include <linux/reboot.h> |
16 | #include <linux/init.h> |
17 | #include <linux/fs.h> |
18 | #include <linux/pci.h> |
19 | #include <linux/uaccess.h> |
20 | #include <linux/io.h> |
21 | |
22 | #define WATCHDOG_NAME "ALi_M1535" |
23 | #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ |
24 | |
25 | /* internal variables */ |
26 | static unsigned long ali_is_open; |
27 | static char ali_expect_release; |
28 | static struct pci_dev *ali_pci; |
29 | static u32 ali_timeout_bits; /* stores the computed timeout */ |
30 | static DEFINE_SPINLOCK(ali_lock); /* Guards the hardware */ |
31 | |
32 | /* module parameters */ |
33 | static int timeout = WATCHDOG_TIMEOUT; |
34 | module_param(timeout, int, 0); |
35 | MODULE_PARM_DESC(timeout, |
36 | "Watchdog timeout in seconds. (0 < timeout < 18000, default=" |
37 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")" ); |
38 | |
39 | static bool nowayout = WATCHDOG_NOWAYOUT; |
40 | module_param(nowayout, bool, 0); |
41 | MODULE_PARM_DESC(nowayout, |
42 | "Watchdog cannot be stopped once started (default=" |
43 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
44 | |
45 | /* |
46 | * ali_start - start watchdog countdown |
47 | * |
48 | * Starts the timer running providing the timer has a counter |
49 | * configuration set. |
50 | */ |
51 | |
52 | static void ali_start(void) |
53 | { |
54 | u32 val; |
55 | |
56 | spin_lock(lock: &ali_lock); |
57 | |
58 | pci_read_config_dword(dev: ali_pci, where: 0xCC, val: &val); |
59 | val &= ~0x3F; /* Mask count */ |
60 | val |= (1 << 25) | ali_timeout_bits; |
61 | pci_write_config_dword(dev: ali_pci, where: 0xCC, val); |
62 | |
63 | spin_unlock(lock: &ali_lock); |
64 | } |
65 | |
66 | /* |
67 | * ali_stop - stop the timer countdown |
68 | * |
69 | * Stop the ALi watchdog countdown |
70 | */ |
71 | |
72 | static void ali_stop(void) |
73 | { |
74 | u32 val; |
75 | |
76 | spin_lock(lock: &ali_lock); |
77 | |
78 | pci_read_config_dword(dev: ali_pci, where: 0xCC, val: &val); |
79 | val &= ~0x3F; /* Mask count to zero (disabled) */ |
80 | val &= ~(1 << 25); /* and for safety mask the reset enable */ |
81 | pci_write_config_dword(dev: ali_pci, where: 0xCC, val); |
82 | |
83 | spin_unlock(lock: &ali_lock); |
84 | } |
85 | |
86 | /* |
87 | * ali_keepalive - send a keepalive to the watchdog |
88 | * |
89 | * Send a keepalive to the timer (actually we restart the timer). |
90 | */ |
91 | |
92 | static void ali_keepalive(void) |
93 | { |
94 | ali_start(); |
95 | } |
96 | |
97 | /* |
98 | * ali_settimer - compute the timer reload value |
99 | * @t: time in seconds |
100 | * |
101 | * Computes the timeout values needed |
102 | */ |
103 | |
104 | static int ali_settimer(int t) |
105 | { |
106 | if (t < 0) |
107 | return -EINVAL; |
108 | else if (t < 60) |
109 | ali_timeout_bits = t|(1 << 6); |
110 | else if (t < 3600) |
111 | ali_timeout_bits = (t / 60)|(1 << 7); |
112 | else if (t < 18000) |
113 | ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7); |
114 | else |
115 | return -EINVAL; |
116 | |
117 | timeout = t; |
118 | return 0; |
119 | } |
120 | |
121 | /* |
122 | * /dev/watchdog handling |
123 | */ |
124 | |
125 | /* |
126 | * ali_write - writes to ALi watchdog |
127 | * @file: file from VFS |
128 | * @data: user address of data |
129 | * @len: length of data |
130 | * @ppos: pointer to the file offset |
131 | * |
132 | * Handle a write to the ALi watchdog. Writing to the file pings |
133 | * the watchdog and resets it. Writing the magic 'V' sequence allows |
134 | * the next close to turn off the watchdog. |
135 | */ |
136 | |
137 | static ssize_t ali_write(struct file *file, const char __user *data, |
138 | size_t len, loff_t *ppos) |
139 | { |
140 | /* See if we got the magic character 'V' and reload the timer */ |
141 | if (len) { |
142 | if (!nowayout) { |
143 | size_t i; |
144 | |
145 | /* note: just in case someone wrote the |
146 | magic character five months ago... */ |
147 | ali_expect_release = 0; |
148 | |
149 | /* scan to see whether or not we got |
150 | the magic character */ |
151 | for (i = 0; i != len; i++) { |
152 | char c; |
153 | if (get_user(c, data + i)) |
154 | return -EFAULT; |
155 | if (c == 'V') |
156 | ali_expect_release = 42; |
157 | } |
158 | } |
159 | |
160 | /* someone wrote to us, we should reload the timer */ |
161 | ali_start(); |
162 | } |
163 | return len; |
164 | } |
165 | |
166 | /* |
167 | * ali_ioctl - handle watchdog ioctls |
168 | * @file: VFS file pointer |
169 | * @cmd: ioctl number |
170 | * @arg: arguments to the ioctl |
171 | * |
172 | * Handle the watchdog ioctls supported by the ALi driver. Really |
173 | * we want an extension to enable irq ack monitoring and the like |
174 | */ |
175 | |
176 | static long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
177 | { |
178 | void __user *argp = (void __user *)arg; |
179 | int __user *p = argp; |
180 | static const struct watchdog_info ident = { |
181 | .options = WDIOF_KEEPALIVEPING | |
182 | WDIOF_SETTIMEOUT | |
183 | WDIOF_MAGICCLOSE, |
184 | .firmware_version = 0, |
185 | .identity = "ALi M1535 WatchDog Timer" , |
186 | }; |
187 | |
188 | switch (cmd) { |
189 | case WDIOC_GETSUPPORT: |
190 | return copy_to_user(to: argp, from: &ident, n: sizeof(ident)) ? -EFAULT : 0; |
191 | |
192 | case WDIOC_GETSTATUS: |
193 | case WDIOC_GETBOOTSTATUS: |
194 | return put_user(0, p); |
195 | case WDIOC_SETOPTIONS: |
196 | { |
197 | int new_options, retval = -EINVAL; |
198 | |
199 | if (get_user(new_options, p)) |
200 | return -EFAULT; |
201 | if (new_options & WDIOS_DISABLECARD) { |
202 | ali_stop(); |
203 | retval = 0; |
204 | } |
205 | if (new_options & WDIOS_ENABLECARD) { |
206 | ali_start(); |
207 | retval = 0; |
208 | } |
209 | return retval; |
210 | } |
211 | case WDIOC_KEEPALIVE: |
212 | ali_keepalive(); |
213 | return 0; |
214 | case WDIOC_SETTIMEOUT: |
215 | { |
216 | int new_timeout; |
217 | if (get_user(new_timeout, p)) |
218 | return -EFAULT; |
219 | if (ali_settimer(t: new_timeout)) |
220 | return -EINVAL; |
221 | ali_keepalive(); |
222 | } |
223 | fallthrough; |
224 | case WDIOC_GETTIMEOUT: |
225 | return put_user(timeout, p); |
226 | default: |
227 | return -ENOTTY; |
228 | } |
229 | } |
230 | |
231 | /* |
232 | * ali_open - handle open of ali watchdog |
233 | * @inode: inode from VFS |
234 | * @file: file from VFS |
235 | * |
236 | * Open the ALi watchdog device. Ensure only one person opens it |
237 | * at a time. Also start the watchdog running. |
238 | */ |
239 | |
240 | static int ali_open(struct inode *inode, struct file *file) |
241 | { |
242 | /* /dev/watchdog can only be opened once */ |
243 | if (test_and_set_bit(nr: 0, addr: &ali_is_open)) |
244 | return -EBUSY; |
245 | |
246 | /* Activate */ |
247 | ali_start(); |
248 | return stream_open(inode, filp: file); |
249 | } |
250 | |
251 | /* |
252 | * ali_release - close an ALi watchdog |
253 | * @inode: inode from VFS |
254 | * @file: file from VFS |
255 | * |
256 | * Close the ALi watchdog device. Actual shutdown of the timer |
257 | * only occurs if the magic sequence has been set. |
258 | */ |
259 | |
260 | static int ali_release(struct inode *inode, struct file *file) |
261 | { |
262 | /* |
263 | * Shut off the timer. |
264 | */ |
265 | if (ali_expect_release == 42) |
266 | ali_stop(); |
267 | else { |
268 | pr_crit("Unexpected close, not stopping watchdog!\n" ); |
269 | ali_keepalive(); |
270 | } |
271 | clear_bit(nr: 0, addr: &ali_is_open); |
272 | ali_expect_release = 0; |
273 | return 0; |
274 | } |
275 | |
276 | /* |
277 | * ali_notify_sys - System down notifier |
278 | * |
279 | * Notifier for system down |
280 | */ |
281 | |
282 | |
283 | static int ali_notify_sys(struct notifier_block *this, |
284 | unsigned long code, void *unused) |
285 | { |
286 | if (code == SYS_DOWN || code == SYS_HALT) |
287 | ali_stop(); /* Turn the WDT off */ |
288 | return NOTIFY_DONE; |
289 | } |
290 | |
291 | /* |
292 | * Data for PCI driver interface |
293 | * |
294 | * This data only exists for exporting the supported |
295 | * PCI ids via MODULE_DEVICE_TABLE. We do not actually |
296 | * register a pci_driver, because someone else might one day |
297 | * want to register another driver on the same PCI id. |
298 | */ |
299 | |
300 | static const struct pci_device_id ali_pci_tbl[] __used = { |
301 | { PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,}, |
302 | { PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,}, |
303 | { 0, }, |
304 | }; |
305 | MODULE_DEVICE_TABLE(pci, ali_pci_tbl); |
306 | |
307 | /* |
308 | * ali_find_watchdog - find a 1535 and 7101 |
309 | * |
310 | * Scans the PCI hardware for a 1535 series bridge and matching 7101 |
311 | * watchdog device. This may be overtight but it is better to be safe |
312 | */ |
313 | |
314 | static int __init ali_find_watchdog(void) |
315 | { |
316 | struct pci_dev *pdev; |
317 | u32 wdog; |
318 | |
319 | /* Check for a 1533/1535 series bridge */ |
320 | pdev = pci_get_device(PCI_VENDOR_ID_AL, device: 0x1535, NULL); |
321 | if (pdev == NULL) |
322 | pdev = pci_get_device(PCI_VENDOR_ID_AL, device: 0x1533, NULL); |
323 | if (pdev == NULL) |
324 | return -ENODEV; |
325 | pci_dev_put(dev: pdev); |
326 | |
327 | /* Check for the a 7101 PMU */ |
328 | pdev = pci_get_device(PCI_VENDOR_ID_AL, device: 0x7101, NULL); |
329 | if (pdev == NULL) |
330 | return -ENODEV; |
331 | |
332 | if (pci_enable_device(dev: pdev)) { |
333 | pci_dev_put(dev: pdev); |
334 | return -EIO; |
335 | } |
336 | |
337 | ali_pci = pdev; |
338 | |
339 | /* |
340 | * Initialize the timer bits |
341 | */ |
342 | pci_read_config_dword(dev: pdev, where: 0xCC, val: &wdog); |
343 | |
344 | /* Timer bits */ |
345 | wdog &= ~0x3F; |
346 | /* Issued events */ |
347 | wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24)); |
348 | /* No monitor bits */ |
349 | wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9)); |
350 | |
351 | pci_write_config_dword(dev: pdev, where: 0xCC, val: wdog); |
352 | |
353 | return 0; |
354 | } |
355 | |
356 | /* |
357 | * Kernel Interfaces |
358 | */ |
359 | |
360 | static const struct file_operations ali_fops = { |
361 | .owner = THIS_MODULE, |
362 | .llseek = no_llseek, |
363 | .write = ali_write, |
364 | .unlocked_ioctl = ali_ioctl, |
365 | .compat_ioctl = compat_ptr_ioctl, |
366 | .open = ali_open, |
367 | .release = ali_release, |
368 | }; |
369 | |
370 | static struct miscdevice ali_miscdev = { |
371 | .minor = WATCHDOG_MINOR, |
372 | .name = "watchdog" , |
373 | .fops = &ali_fops, |
374 | }; |
375 | |
376 | static struct notifier_block ali_notifier = { |
377 | .notifier_call = ali_notify_sys, |
378 | }; |
379 | |
380 | /* |
381 | * watchdog_init - module initialiser |
382 | * |
383 | * Scan for a suitable watchdog and if so initialize it. Return an error |
384 | * if we cannot, the error causes the module to unload |
385 | */ |
386 | |
387 | static int __init watchdog_init(void) |
388 | { |
389 | int ret; |
390 | |
391 | /* Check whether or not the hardware watchdog is there */ |
392 | if (ali_find_watchdog() != 0) |
393 | return -ENODEV; |
394 | |
395 | /* Check that the timeout value is within it's range; |
396 | if not reset to the default */ |
397 | if (timeout < 1 || timeout >= 18000) { |
398 | timeout = WATCHDOG_TIMEOUT; |
399 | pr_info("timeout value must be 0 < timeout < 18000, using %d\n" , |
400 | timeout); |
401 | } |
402 | |
403 | /* Calculate the watchdog's timeout */ |
404 | ali_settimer(t: timeout); |
405 | |
406 | ret = register_reboot_notifier(&ali_notifier); |
407 | if (ret != 0) { |
408 | pr_err("cannot register reboot notifier (err=%d)\n" , ret); |
409 | goto out; |
410 | } |
411 | |
412 | ret = misc_register(misc: &ali_miscdev); |
413 | if (ret != 0) { |
414 | pr_err("cannot register miscdev on minor=%d (err=%d)\n" , |
415 | WATCHDOG_MINOR, ret); |
416 | goto unreg_reboot; |
417 | } |
418 | |
419 | pr_info("initialized. timeout=%d sec (nowayout=%d)\n" , |
420 | timeout, nowayout); |
421 | |
422 | out: |
423 | return ret; |
424 | unreg_reboot: |
425 | unregister_reboot_notifier(&ali_notifier); |
426 | goto out; |
427 | } |
428 | |
429 | /* |
430 | * watchdog_exit - module de-initialiser |
431 | * |
432 | * Called while unloading a successfully installed watchdog module. |
433 | */ |
434 | |
435 | static void __exit watchdog_exit(void) |
436 | { |
437 | /* Stop the timer before we leave */ |
438 | ali_stop(); |
439 | |
440 | /* Deregister */ |
441 | misc_deregister(misc: &ali_miscdev); |
442 | unregister_reboot_notifier(&ali_notifier); |
443 | pci_dev_put(dev: ali_pci); |
444 | } |
445 | |
446 | module_init(watchdog_init); |
447 | module_exit(watchdog_exit); |
448 | |
449 | MODULE_AUTHOR("Alan Cox" ); |
450 | MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver" ); |
451 | MODULE_LICENSE("GPL" ); |
452 | |