Commit | Line | Data |
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f7a94db4 | 1 | /* |
646f919e | 2 | * Watchdog driver for z/VM and LPAR using the diag 288 interface. |
f7a94db4 PH |
3 | * |
4 | * Under z/VM, expiration of the watchdog will send a "system restart" command | |
5 | * to CP. | |
6 | * | |
646f919e PH |
7 | * The command can be altered using the module parameter "cmd". This is |
8 | * not recommended because it's only supported on z/VM but not whith LPAR. | |
9 | * | |
10 | * On LPAR, the watchdog will always trigger a system restart. the module | |
11 | * paramter cmd is meaningless here. | |
12 | * | |
f7a94db4 PH |
13 | * |
14 | * Copyright IBM Corp. 2004, 2013 | |
15 | * Author(s): Arnd Bergmann (arndb@de.ibm.com) | |
16 | * Philipp Hachtmann (phacht@de.ibm.com) | |
17 | * | |
18 | */ | |
19 | ||
20 | #define KMSG_COMPONENT "diag288_wdt" | |
21 | #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt | |
22 | ||
23 | #include <linux/init.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/moduleparam.h> | |
27 | #include <linux/slab.h> | |
28 | #include <linux/miscdevice.h> | |
29 | #include <linux/watchdog.h> | |
30 | #include <linux/suspend.h> | |
31 | #include <asm/ebcdic.h> | |
32 | #include <linux/io.h> | |
33 | #include <linux/uaccess.h> | |
34 | ||
35 | #define MAX_CMDLEN 240 | |
36 | #define DEFAULT_CMD "SYSTEM RESTART" | |
37 | ||
38 | #define MIN_INTERVAL 15 /* Minimal time supported by diag88 */ | |
39 | #define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */ | |
40 | ||
41 | #define WDT_DEFAULT_TIMEOUT 30 | |
42 | ||
43 | /* Function codes - init, change, cancel */ | |
44 | #define WDT_FUNC_INIT 0 | |
45 | #define WDT_FUNC_CHANGE 1 | |
46 | #define WDT_FUNC_CANCEL 2 | |
47 | #define WDT_FUNC_CONCEAL 0x80000000 | |
48 | ||
646f919e PH |
49 | /* Action codes for LPAR watchdog */ |
50 | #define LPARWDT_RESTART 0 | |
51 | ||
f7a94db4 PH |
52 | static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD; |
53 | static bool conceal_on; | |
54 | static bool nowayout_info = WATCHDOG_NOWAYOUT; | |
55 | ||
56 | MODULE_LICENSE("GPL"); | |
57 | MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>"); | |
58 | MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>"); | |
59 | ||
60 | MODULE_DESCRIPTION("System z diag288 Watchdog Timer"); | |
61 | ||
62 | module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644); | |
63 | MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)"); | |
64 | ||
65 | module_param_named(conceal, conceal_on, bool, 0644); | |
66 | MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)"); | |
67 | ||
68 | module_param_named(nowayout, nowayout_info, bool, 0444); | |
69 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)"); | |
70 | ||
71 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
72 | MODULE_ALIAS("vmwatchdog"); | |
73 | ||
74 | static int __diag288(unsigned int func, unsigned int timeout, | |
75 | unsigned long action, unsigned int len) | |
76 | { | |
77 | register unsigned long __func asm("2") = func; | |
78 | register unsigned long __timeout asm("3") = timeout; | |
79 | register unsigned long __action asm("4") = action; | |
80 | register unsigned long __len asm("5") = len; | |
81 | int err; | |
82 | ||
83 | err = -EINVAL; | |
84 | asm volatile( | |
85 | " diag %1, %3, 0x288\n" | |
86 | "0: la %0, 0\n" | |
87 | "1:\n" | |
88 | EX_TABLE(0b, 1b) | |
89 | : "+d" (err) : "d"(__func), "d"(__timeout), | |
90 | "d"(__action), "d"(__len) : "1", "cc"); | |
91 | return err; | |
92 | } | |
93 | ||
94 | static int __diag288_vm(unsigned int func, unsigned int timeout, | |
95 | char *cmd, size_t len) | |
96 | { | |
97 | return __diag288(func, timeout, virt_to_phys(cmd), len); | |
98 | } | |
99 | ||
646f919e PH |
100 | static int __diag288_lpar(unsigned int func, unsigned int timeout, |
101 | unsigned long action) | |
102 | { | |
103 | return __diag288(func, timeout, action, 0); | |
104 | } | |
105 | ||
f7a94db4 PH |
106 | static int wdt_start(struct watchdog_device *dev) |
107 | { | |
108 | char *ebc_cmd; | |
109 | size_t len; | |
110 | int ret; | |
111 | unsigned int func; | |
112 | ||
113 | ret = -ENODEV; | |
114 | ||
115 | if (MACHINE_IS_VM) { | |
116 | ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); | |
117 | if (!ebc_cmd) | |
118 | return -ENOMEM; | |
119 | len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); | |
120 | ASCEBC(ebc_cmd, MAX_CMDLEN); | |
121 | EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); | |
122 | ||
123 | func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) | |
124 | : WDT_FUNC_INIT; | |
125 | ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); | |
126 | WARN_ON(ret != 0); | |
127 | kfree(ebc_cmd); | |
128 | } | |
129 | ||
646f919e PH |
130 | if (MACHINE_IS_LPAR) { |
131 | ret = __diag288_lpar(WDT_FUNC_INIT, | |
132 | dev->timeout, LPARWDT_RESTART); | |
133 | } | |
134 | ||
f7a94db4 PH |
135 | if (ret) { |
136 | pr_err("The watchdog cannot be activated\n"); | |
137 | return ret; | |
138 | } | |
139 | pr_info("The watchdog was activated\n"); | |
140 | return 0; | |
141 | } | |
142 | ||
143 | static int wdt_stop(struct watchdog_device *dev) | |
144 | { | |
145 | int ret; | |
146 | ||
147 | ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0); | |
148 | pr_info("The watchdog was deactivated\n"); | |
149 | return ret; | |
150 | } | |
151 | ||
152 | static int wdt_ping(struct watchdog_device *dev) | |
153 | { | |
154 | char *ebc_cmd; | |
155 | size_t len; | |
156 | int ret; | |
157 | unsigned int func; | |
158 | ||
159 | ret = -ENODEV; | |
160 | ||
161 | if (MACHINE_IS_VM) { | |
162 | ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); | |
163 | if (!ebc_cmd) | |
164 | return -ENOMEM; | |
165 | len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); | |
166 | ASCEBC(ebc_cmd, MAX_CMDLEN); | |
167 | EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); | |
168 | ||
169 | /* | |
170 | * It seems to be ok to z/VM to use the init function to | |
646f919e PH |
171 | * retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must |
172 | * be used when the watchdog is running. | |
f7a94db4 PH |
173 | */ |
174 | func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) | |
175 | : WDT_FUNC_INIT; | |
176 | ||
177 | ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); | |
178 | WARN_ON(ret != 0); | |
179 | kfree(ebc_cmd); | |
180 | } | |
181 | ||
646f919e PH |
182 | if (MACHINE_IS_LPAR) |
183 | ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0); | |
184 | ||
f7a94db4 PH |
185 | if (ret) |
186 | pr_err("The watchdog timer cannot be started or reset\n"); | |
187 | return ret; | |
188 | } | |
189 | ||
190 | static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to) | |
191 | { | |
192 | dev->timeout = new_to; | |
193 | return wdt_ping(dev); | |
194 | } | |
195 | ||
196 | static struct watchdog_ops wdt_ops = { | |
197 | .owner = THIS_MODULE, | |
198 | .start = wdt_start, | |
199 | .stop = wdt_stop, | |
200 | .ping = wdt_ping, | |
201 | .set_timeout = wdt_set_timeout, | |
202 | }; | |
203 | ||
204 | static struct watchdog_info wdt_info = { | |
205 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, | |
206 | .firmware_version = 0, | |
207 | .identity = "z Watchdog", | |
208 | }; | |
209 | ||
210 | static struct watchdog_device wdt_dev = { | |
211 | .parent = NULL, | |
212 | .info = &wdt_info, | |
213 | .ops = &wdt_ops, | |
214 | .bootstatus = 0, | |
215 | .timeout = WDT_DEFAULT_TIMEOUT, | |
216 | .min_timeout = MIN_INTERVAL, | |
217 | .max_timeout = MAX_INTERVAL, | |
218 | }; | |
219 | ||
220 | /* | |
221 | * It makes no sense to go into suspend while the watchdog is running. | |
222 | * Depending on the memory size, the watchdog might trigger, while we | |
223 | * are still saving the memory. | |
224 | * We reuse the open flag to ensure that suspend and watchdog open are | |
225 | * exclusive operations | |
226 | */ | |
227 | static int wdt_suspend(void) | |
228 | { | |
229 | if (test_and_set_bit(WDOG_DEV_OPEN, &wdt_dev.status)) { | |
230 | pr_err("Linux cannot be suspended while the watchdog is in use\n"); | |
231 | return notifier_from_errno(-EBUSY); | |
232 | } | |
233 | if (test_bit(WDOG_ACTIVE, &wdt_dev.status)) { | |
234 | clear_bit(WDOG_DEV_OPEN, &wdt_dev.status); | |
235 | pr_err("Linux cannot be suspended while the watchdog is in use\n"); | |
236 | return notifier_from_errno(-EBUSY); | |
237 | } | |
238 | return NOTIFY_DONE; | |
239 | } | |
240 | ||
241 | static int wdt_resume(void) | |
242 | { | |
243 | clear_bit(WDOG_DEV_OPEN, &wdt_dev.status); | |
244 | return NOTIFY_DONE; | |
245 | } | |
246 | ||
247 | static int wdt_power_event(struct notifier_block *this, unsigned long event, | |
248 | void *ptr) | |
249 | { | |
250 | switch (event) { | |
251 | case PM_POST_HIBERNATION: | |
252 | case PM_POST_SUSPEND: | |
253 | return wdt_resume(); | |
254 | case PM_HIBERNATION_PREPARE: | |
255 | case PM_SUSPEND_PREPARE: | |
256 | return wdt_suspend(); | |
257 | default: | |
258 | return NOTIFY_DONE; | |
259 | } | |
260 | } | |
261 | ||
262 | static struct notifier_block wdt_power_notifier = { | |
263 | .notifier_call = wdt_power_event, | |
264 | }; | |
265 | ||
266 | static int __init diag288_init(void) | |
267 | { | |
268 | int ret; | |
269 | char ebc_begin[] = { | |
270 | 194, 197, 199, 201, 213 | |
271 | }; | |
272 | ||
273 | watchdog_set_nowayout(&wdt_dev, nowayout_info); | |
274 | ||
275 | if (MACHINE_IS_VM) { | |
276 | pr_info("The watchdog device driver detected a z/VM environment\n"); | |
277 | if (__diag288_vm(WDT_FUNC_INIT, 15, | |
278 | ebc_begin, sizeof(ebc_begin)) != 0) { | |
279 | pr_err("The watchdog cannot be initialized\n"); | |
280 | return -EINVAL; | |
281 | } | |
646f919e PH |
282 | } else if (MACHINE_IS_LPAR) { |
283 | pr_info("The watchdog device driver detected an LPAR environment\n"); | |
284 | if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) { | |
285 | pr_err("The watchdog cannot be initialized\n"); | |
286 | return -EINVAL; | |
287 | } | |
f7a94db4 PH |
288 | } else { |
289 | pr_err("Linux runs in an environment that does not support the diag288 watchdog\n"); | |
290 | return -ENODEV; | |
291 | } | |
292 | ||
646f919e | 293 | if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) { |
f7a94db4 PH |
294 | pr_err("The watchdog cannot be deactivated\n"); |
295 | return -EINVAL; | |
296 | } | |
297 | ||
298 | ret = register_pm_notifier(&wdt_power_notifier); | |
299 | if (ret) | |
300 | return ret; | |
301 | ||
302 | ret = watchdog_register_device(&wdt_dev); | |
303 | if (ret) | |
304 | unregister_pm_notifier(&wdt_power_notifier); | |
305 | ||
306 | return ret; | |
307 | } | |
308 | ||
309 | static void __exit diag288_exit(void) | |
310 | { | |
311 | watchdog_unregister_device(&wdt_dev); | |
312 | unregister_pm_notifier(&wdt_power_notifier); | |
313 | } | |
314 | ||
315 | module_init(diag288_init); | |
316 | module_exit(diag288_exit); |