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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> | |
1ec2772e | 32 | #include <asm/diag.h> |
f7a94db4 PH |
33 | #include <linux/io.h> |
34 | #include <linux/uaccess.h> | |
35 | ||
36 | #define MAX_CMDLEN 240 | |
37 | #define DEFAULT_CMD "SYSTEM RESTART" | |
38 | ||
39 | #define MIN_INTERVAL 15 /* Minimal time supported by diag88 */ | |
40 | #define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */ | |
41 | ||
42 | #define WDT_DEFAULT_TIMEOUT 30 | |
43 | ||
44 | /* Function codes - init, change, cancel */ | |
45 | #define WDT_FUNC_INIT 0 | |
46 | #define WDT_FUNC_CHANGE 1 | |
47 | #define WDT_FUNC_CANCEL 2 | |
48 | #define WDT_FUNC_CONCEAL 0x80000000 | |
49 | ||
646f919e PH |
50 | /* Action codes for LPAR watchdog */ |
51 | #define LPARWDT_RESTART 0 | |
52 | ||
f7a94db4 PH |
53 | static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD; |
54 | static bool conceal_on; | |
55 | static bool nowayout_info = WATCHDOG_NOWAYOUT; | |
56 | ||
57 | MODULE_LICENSE("GPL"); | |
58 | MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>"); | |
59 | MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>"); | |
60 | ||
61 | MODULE_DESCRIPTION("System z diag288 Watchdog Timer"); | |
62 | ||
63 | module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644); | |
64 | MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)"); | |
65 | ||
66 | module_param_named(conceal, conceal_on, bool, 0644); | |
67 | MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)"); | |
68 | ||
69 | module_param_named(nowayout, nowayout_info, bool, 0444); | |
70 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)"); | |
71 | ||
72 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
73 | MODULE_ALIAS("vmwatchdog"); | |
74 | ||
75 | static int __diag288(unsigned int func, unsigned int timeout, | |
76 | unsigned long action, unsigned int len) | |
77 | { | |
78 | register unsigned long __func asm("2") = func; | |
79 | register unsigned long __timeout asm("3") = timeout; | |
80 | register unsigned long __action asm("4") = action; | |
81 | register unsigned long __len asm("5") = len; | |
82 | int err; | |
83 | ||
84 | err = -EINVAL; | |
85 | asm volatile( | |
86 | " diag %1, %3, 0x288\n" | |
87 | "0: la %0, 0\n" | |
88 | "1:\n" | |
89 | EX_TABLE(0b, 1b) | |
90 | : "+d" (err) : "d"(__func), "d"(__timeout), | |
91 | "d"(__action), "d"(__len) : "1", "cc"); | |
92 | return err; | |
93 | } | |
94 | ||
95 | static int __diag288_vm(unsigned int func, unsigned int timeout, | |
96 | char *cmd, size_t len) | |
97 | { | |
1ec2772e | 98 | diag_stat_inc(DIAG_STAT_X288); |
f7a94db4 PH |
99 | return __diag288(func, timeout, virt_to_phys(cmd), len); |
100 | } | |
101 | ||
646f919e PH |
102 | static int __diag288_lpar(unsigned int func, unsigned int timeout, |
103 | unsigned long action) | |
104 | { | |
1ec2772e | 105 | diag_stat_inc(DIAG_STAT_X288); |
646f919e PH |
106 | return __diag288(func, timeout, action, 0); |
107 | } | |
108 | ||
e7d162fa GR |
109 | static unsigned long wdt_status; |
110 | ||
111 | #define DIAG_WDOG_BUSY 0 | |
112 | ||
f7a94db4 PH |
113 | static int wdt_start(struct watchdog_device *dev) |
114 | { | |
115 | char *ebc_cmd; | |
116 | size_t len; | |
117 | int ret; | |
118 | unsigned int func; | |
119 | ||
e7d162fa GR |
120 | if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) |
121 | return -EBUSY; | |
122 | ||
f7a94db4 PH |
123 | ret = -ENODEV; |
124 | ||
125 | if (MACHINE_IS_VM) { | |
126 | ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); | |
e7d162fa GR |
127 | if (!ebc_cmd) { |
128 | clear_bit(DIAG_WDOG_BUSY, &wdt_status); | |
f7a94db4 | 129 | return -ENOMEM; |
e7d162fa | 130 | } |
f7a94db4 PH |
131 | len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); |
132 | ASCEBC(ebc_cmd, MAX_CMDLEN); | |
133 | EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); | |
134 | ||
135 | func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) | |
136 | : WDT_FUNC_INIT; | |
137 | ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); | |
138 | WARN_ON(ret != 0); | |
139 | kfree(ebc_cmd); | |
b2527d20 | 140 | } else { |
646f919e PH |
141 | ret = __diag288_lpar(WDT_FUNC_INIT, |
142 | dev->timeout, LPARWDT_RESTART); | |
143 | } | |
144 | ||
f7a94db4 PH |
145 | if (ret) { |
146 | pr_err("The watchdog cannot be activated\n"); | |
e7d162fa | 147 | clear_bit(DIAG_WDOG_BUSY, &wdt_status); |
f7a94db4 PH |
148 | return ret; |
149 | } | |
f7a94db4 PH |
150 | return 0; |
151 | } | |
152 | ||
153 | static int wdt_stop(struct watchdog_device *dev) | |
154 | { | |
155 | int ret; | |
156 | ||
1ec2772e | 157 | diag_stat_inc(DIAG_STAT_X288); |
f7a94db4 | 158 | ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0); |
e7d162fa GR |
159 | |
160 | clear_bit(DIAG_WDOG_BUSY, &wdt_status); | |
161 | ||
f7a94db4 PH |
162 | return ret; |
163 | } | |
164 | ||
165 | static int wdt_ping(struct watchdog_device *dev) | |
166 | { | |
167 | char *ebc_cmd; | |
168 | size_t len; | |
169 | int ret; | |
170 | unsigned int func; | |
171 | ||
172 | ret = -ENODEV; | |
173 | ||
174 | if (MACHINE_IS_VM) { | |
175 | ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); | |
176 | if (!ebc_cmd) | |
177 | return -ENOMEM; | |
178 | len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); | |
179 | ASCEBC(ebc_cmd, MAX_CMDLEN); | |
180 | EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); | |
181 | ||
182 | /* | |
183 | * It seems to be ok to z/VM to use the init function to | |
646f919e PH |
184 | * retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must |
185 | * be used when the watchdog is running. | |
f7a94db4 PH |
186 | */ |
187 | func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) | |
188 | : WDT_FUNC_INIT; | |
189 | ||
190 | ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); | |
191 | WARN_ON(ret != 0); | |
192 | kfree(ebc_cmd); | |
b2527d20 | 193 | } else { |
646f919e | 194 | ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0); |
b2527d20 | 195 | } |
646f919e | 196 | |
f7a94db4 PH |
197 | if (ret) |
198 | pr_err("The watchdog timer cannot be started or reset\n"); | |
199 | return ret; | |
200 | } | |
201 | ||
202 | static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to) | |
203 | { | |
204 | dev->timeout = new_to; | |
205 | return wdt_ping(dev); | |
206 | } | |
207 | ||
b893e344 | 208 | static const struct watchdog_ops wdt_ops = { |
f7a94db4 PH |
209 | .owner = THIS_MODULE, |
210 | .start = wdt_start, | |
211 | .stop = wdt_stop, | |
212 | .ping = wdt_ping, | |
213 | .set_timeout = wdt_set_timeout, | |
214 | }; | |
215 | ||
216 | static struct watchdog_info wdt_info = { | |
9ec6cb80 | 217 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
f7a94db4 PH |
218 | .firmware_version = 0, |
219 | .identity = "z Watchdog", | |
220 | }; | |
221 | ||
222 | static struct watchdog_device wdt_dev = { | |
223 | .parent = NULL, | |
224 | .info = &wdt_info, | |
225 | .ops = &wdt_ops, | |
226 | .bootstatus = 0, | |
227 | .timeout = WDT_DEFAULT_TIMEOUT, | |
228 | .min_timeout = MIN_INTERVAL, | |
229 | .max_timeout = MAX_INTERVAL, | |
230 | }; | |
231 | ||
232 | /* | |
233 | * It makes no sense to go into suspend while the watchdog is running. | |
234 | * Depending on the memory size, the watchdog might trigger, while we | |
235 | * are still saving the memory. | |
f7a94db4 PH |
236 | */ |
237 | static int wdt_suspend(void) | |
238 | { | |
e7d162fa | 239 | if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) { |
f7a94db4 PH |
240 | pr_err("Linux cannot be suspended while the watchdog is in use\n"); |
241 | return notifier_from_errno(-EBUSY); | |
242 | } | |
243 | return NOTIFY_DONE; | |
244 | } | |
245 | ||
246 | static int wdt_resume(void) | |
247 | { | |
e7d162fa | 248 | clear_bit(DIAG_WDOG_BUSY, &wdt_status); |
f7a94db4 PH |
249 | return NOTIFY_DONE; |
250 | } | |
251 | ||
252 | static int wdt_power_event(struct notifier_block *this, unsigned long event, | |
253 | void *ptr) | |
254 | { | |
255 | switch (event) { | |
256 | case PM_POST_HIBERNATION: | |
257 | case PM_POST_SUSPEND: | |
258 | return wdt_resume(); | |
259 | case PM_HIBERNATION_PREPARE: | |
260 | case PM_SUSPEND_PREPARE: | |
261 | return wdt_suspend(); | |
262 | default: | |
263 | return NOTIFY_DONE; | |
264 | } | |
265 | } | |
266 | ||
267 | static struct notifier_block wdt_power_notifier = { | |
268 | .notifier_call = wdt_power_event, | |
269 | }; | |
270 | ||
271 | static int __init diag288_init(void) | |
272 | { | |
273 | int ret; | |
274 | char ebc_begin[] = { | |
275 | 194, 197, 199, 201, 213 | |
276 | }; | |
277 | ||
278 | watchdog_set_nowayout(&wdt_dev, nowayout_info); | |
279 | ||
280 | if (MACHINE_IS_VM) { | |
f7a94db4 PH |
281 | if (__diag288_vm(WDT_FUNC_INIT, 15, |
282 | ebc_begin, sizeof(ebc_begin)) != 0) { | |
283 | pr_err("The watchdog cannot be initialized\n"); | |
284 | return -EINVAL; | |
285 | } | |
b2527d20 | 286 | } else { |
646f919e PH |
287 | if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) { |
288 | pr_err("The watchdog cannot be initialized\n"); | |
289 | return -EINVAL; | |
290 | } | |
f7a94db4 PH |
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); |