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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 <asm/diag.h>
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
40#define MAX_INTERVAL 3600
41
42#define WDT_DEFAULT_TIMEOUT 30
43
44
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
50
51#define LPARWDT_RESTART 0
52
53static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD;
54static bool conceal_on;
55static bool nowayout_info = WATCHDOG_NOWAYOUT;
56
57MODULE_LICENSE("GPL");
58MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
59MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>");
60
61MODULE_DESCRIPTION("System z diag288 Watchdog Timer");
62
63module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644);
64MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)");
65
66module_param_named(conceal, conceal_on, bool, 0644);
67MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)");
68
69module_param_named(nowayout, nowayout_info, bool, 0444);
70MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)");
71
72MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
73MODULE_ALIAS("vmwatchdog");
74
75static 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
95static int __diag288_vm(unsigned int func, unsigned int timeout,
96 char *cmd, size_t len)
97{
98 diag_stat_inc(DIAG_STAT_X288);
99 return __diag288(func, timeout, virt_to_phys(cmd), len);
100}
101
102static int __diag288_lpar(unsigned int func, unsigned int timeout,
103 unsigned long action)
104{
105 diag_stat_inc(DIAG_STAT_X288);
106 return __diag288(func, timeout, action, 0);
107}
108
109static int wdt_start(struct watchdog_device *dev)
110{
111 char *ebc_cmd;
112 size_t len;
113 int ret;
114 unsigned int func;
115
116 ret = -ENODEV;
117
118 if (MACHINE_IS_VM) {
119 ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
120 if (!ebc_cmd)
121 return -ENOMEM;
122 len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
123 ASCEBC(ebc_cmd, MAX_CMDLEN);
124 EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
125
126 func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
127 : WDT_FUNC_INIT;
128 ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
129 WARN_ON(ret != 0);
130 kfree(ebc_cmd);
131 } else {
132 ret = __diag288_lpar(WDT_FUNC_INIT,
133 dev->timeout, LPARWDT_RESTART);
134 }
135
136 if (ret) {
137 pr_err("The watchdog cannot be activated\n");
138 return ret;
139 }
140 return 0;
141}
142
143static int wdt_stop(struct watchdog_device *dev)
144{
145 int ret;
146
147 diag_stat_inc(DIAG_STAT_X288);
148 ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
149 return ret;
150}
151
152static 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
171
172
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 } else {
181 ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);
182 }
183
184 if (ret)
185 pr_err("The watchdog timer cannot be started or reset\n");
186 return ret;
187}
188
189static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
190{
191 dev->timeout = new_to;
192 return wdt_ping(dev);
193}
194
195static struct watchdog_ops wdt_ops = {
196 .owner = THIS_MODULE,
197 .start = wdt_start,
198 .stop = wdt_stop,
199 .ping = wdt_ping,
200 .set_timeout = wdt_set_timeout,
201};
202
203static struct watchdog_info wdt_info = {
204 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
205 .firmware_version = 0,
206 .identity = "z Watchdog",
207};
208
209static struct watchdog_device wdt_dev = {
210 .parent = NULL,
211 .info = &wdt_info,
212 .ops = &wdt_ops,
213 .bootstatus = 0,
214 .timeout = WDT_DEFAULT_TIMEOUT,
215 .min_timeout = MIN_INTERVAL,
216 .max_timeout = MAX_INTERVAL,
217};
218
219
220
221
222
223
224
225
226static int wdt_suspend(void)
227{
228 if (test_and_set_bit(WDOG_DEV_OPEN, &wdt_dev.status)) {
229 pr_err("Linux cannot be suspended while the watchdog is in use\n");
230 return notifier_from_errno(-EBUSY);
231 }
232 if (test_bit(WDOG_ACTIVE, &wdt_dev.status)) {
233 clear_bit(WDOG_DEV_OPEN, &wdt_dev.status);
234 pr_err("Linux cannot be suspended while the watchdog is in use\n");
235 return notifier_from_errno(-EBUSY);
236 }
237 return NOTIFY_DONE;
238}
239
240static int wdt_resume(void)
241{
242 clear_bit(WDOG_DEV_OPEN, &wdt_dev.status);
243 return NOTIFY_DONE;
244}
245
246static int wdt_power_event(struct notifier_block *this, unsigned long event,
247 void *ptr)
248{
249 switch (event) {
250 case PM_POST_HIBERNATION:
251 case PM_POST_SUSPEND:
252 return wdt_resume();
253 case PM_HIBERNATION_PREPARE:
254 case PM_SUSPEND_PREPARE:
255 return wdt_suspend();
256 default:
257 return NOTIFY_DONE;
258 }
259}
260
261static struct notifier_block wdt_power_notifier = {
262 .notifier_call = wdt_power_event,
263};
264
265static int __init diag288_init(void)
266{
267 int ret;
268 char ebc_begin[] = {
269 194, 197, 199, 201, 213
270 };
271
272 watchdog_set_nowayout(&wdt_dev, nowayout_info);
273
274 if (MACHINE_IS_VM) {
275 if (__diag288_vm(WDT_FUNC_INIT, 15,
276 ebc_begin, sizeof(ebc_begin)) != 0) {
277 pr_err("The watchdog cannot be initialized\n");
278 return -EINVAL;
279 }
280 } else {
281 if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {
282 pr_err("The watchdog cannot be initialized\n");
283 return -EINVAL;
284 }
285 }
286
287 if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) {
288 pr_err("The watchdog cannot be deactivated\n");
289 return -EINVAL;
290 }
291
292 ret = register_pm_notifier(&wdt_power_notifier);
293 if (ret)
294 return ret;
295
296 ret = watchdog_register_device(&wdt_dev);
297 if (ret)
298 unregister_pm_notifier(&wdt_power_notifier);
299
300 return ret;
301}
302
303static void __exit diag288_exit(void)
304{
305 watchdog_unregister_device(&wdt_dev);
306 unregister_pm_notifier(&wdt_power_notifier);
307}
308
309module_init(diag288_init);
310module_exit(diag288_exit);
311
