2 * SVC Greybus "watchdog" driver.
4 * Copyright 2016 Google Inc.
6 * Released under the GPLv2 only.
9 #include <linux/delay.h>
10 #include <linux/suspend.h>
11 #include <linux/workqueue.h>
14 #define SVC_WATCHDOG_PERIOD (2 * HZ)
16 struct gb_svc_watchdog {
17 struct delayed_work work;
20 struct notifier_block pm_notifier;
23 static struct delayed_work reset_work;
25 static int svc_watchdog_pm_notifier(struct notifier_block *notifier,
26 unsigned long pm_event, void *unused)
28 struct gb_svc_watchdog *watchdog =
29 container_of(notifier, struct gb_svc_watchdog, pm_notifier);
32 case PM_SUSPEND_PREPARE:
33 gb_svc_watchdog_disable(watchdog->svc);
36 gb_svc_watchdog_enable(watchdog->svc);
45 static void greybus_reset(struct work_struct *work)
47 static char const start_path[] = "/system/bin/start";
48 static char *envp[] = {
50 "PATH=/sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin",
53 static char *argv[] = {
59 pr_err("svc_watchdog: calling \"%s %s\" to reset greybus network!\n",
61 call_usermodehelper(start_path, argv, envp, UMH_WAIT_EXEC);
64 static void do_work(struct work_struct *work)
66 struct gb_svc_watchdog *watchdog;
70 watchdog = container_of(work, struct gb_svc_watchdog, work.work);
73 dev_dbg(&svc->dev, "%s: ping.\n", __func__);
74 retval = gb_svc_ping(svc);
77 * Something went really wrong, let's warn userspace and then
78 * pull the plug and reset the whole greybus network.
79 * We need to do this outside of this workqueue as we will be
80 * tearing down the svc device itself. So queue up
81 * yet-another-callback to do that.
84 "SVC ping has returned %d, something is wrong!!!\n",
87 if (svc->action == GB_SVC_WATCHDOG_BITE_PANIC_KERNEL) {
88 panic("SVC is not responding\n");
89 } else if (svc->action == GB_SVC_WATCHDOG_BITE_RESET_UNIPRO) {
90 dev_err(&svc->dev, "Resetting the greybus network, watch out!!!\n");
92 INIT_DELAYED_WORK(&reset_work, greybus_reset);
93 schedule_delayed_work(&reset_work, HZ / 2);
96 * Disable ourselves, we don't want to trip again unless
97 * userspace wants us to.
99 watchdog->enabled = false;
103 /* resubmit our work to happen again, if we are still "alive" */
104 if (watchdog->enabled)
105 schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
108 int gb_svc_watchdog_create(struct gb_svc *svc)
110 struct gb_svc_watchdog *watchdog;
116 watchdog = kmalloc(sizeof(*watchdog), GFP_KERNEL);
120 watchdog->enabled = false;
122 INIT_DELAYED_WORK(&watchdog->work, do_work);
123 svc->watchdog = watchdog;
125 watchdog->pm_notifier.notifier_call = svc_watchdog_pm_notifier;
126 retval = register_pm_notifier(&watchdog->pm_notifier);
128 dev_err(&svc->dev, "error registering pm notifier(%d)\n",
130 goto svc_watchdog_create_err;
133 retval = gb_svc_watchdog_enable(svc);
135 dev_err(&svc->dev, "error enabling watchdog (%d)\n", retval);
136 unregister_pm_notifier(&watchdog->pm_notifier);
137 goto svc_watchdog_create_err;
141 svc_watchdog_create_err:
142 svc->watchdog = NULL;
148 void gb_svc_watchdog_destroy(struct gb_svc *svc)
150 struct gb_svc_watchdog *watchdog = svc->watchdog;
155 unregister_pm_notifier(&watchdog->pm_notifier);
156 gb_svc_watchdog_disable(svc);
157 svc->watchdog = NULL;
161 bool gb_svc_watchdog_enabled(struct gb_svc *svc)
163 if (!svc || !svc->watchdog)
165 return svc->watchdog->enabled;
168 int gb_svc_watchdog_enable(struct gb_svc *svc)
170 struct gb_svc_watchdog *watchdog;
175 watchdog = svc->watchdog;
176 if (watchdog->enabled)
179 watchdog->enabled = true;
180 schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
184 int gb_svc_watchdog_disable(struct gb_svc *svc)
186 struct gb_svc_watchdog *watchdog;
191 watchdog = svc->watchdog;
192 if (!watchdog->enabled)
195 watchdog->enabled = false;
196 cancel_delayed_work_sync(&watchdog->work);