1 // SPDX-License-Identifier: GPL-2.0
3 * SVC Greybus "watchdog" driver.
5 * Copyright 2016 Google Inc.
8 #include <linux/delay.h>
9 #include <linux/suspend.h>
10 #include <linux/workqueue.h>
11 #include <linux/greybus.h>
13 #define SVC_WATCHDOG_PERIOD (2 * HZ)
15 struct gb_svc_watchdog {
16 struct delayed_work work;
19 struct notifier_block pm_notifier;
22 static struct delayed_work reset_work;
24 static int svc_watchdog_pm_notifier(struct notifier_block *notifier,
25 unsigned long pm_event, void *unused)
27 struct gb_svc_watchdog *watchdog =
28 container_of(notifier, struct gb_svc_watchdog, pm_notifier);
31 case PM_SUSPEND_PREPARE:
32 gb_svc_watchdog_disable(watchdog->svc);
35 gb_svc_watchdog_enable(watchdog->svc);
44 static void greybus_reset(struct work_struct *work)
46 static char const start_path[] = "/system/bin/start";
47 static char *envp[] = {
49 "PATH=/sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin",
52 static char *argv[] = {
58 pr_err("svc_watchdog: calling \"%s %s\" to reset greybus network!\n",
60 call_usermodehelper(start_path, argv, envp, UMH_WAIT_EXEC);
63 static void do_work(struct work_struct *work)
65 struct gb_svc_watchdog *watchdog;
69 watchdog = container_of(work, struct gb_svc_watchdog, work.work);
72 dev_dbg(&svc->dev, "%s: ping.\n", __func__);
73 retval = gb_svc_ping(svc);
76 * Something went really wrong, let's warn userspace and then
77 * pull the plug and reset the whole greybus network.
78 * We need to do this outside of this workqueue as we will be
79 * tearing down the svc device itself. So queue up
80 * yet-another-callback to do that.
83 "SVC ping has returned %d, something is wrong!!!\n",
86 if (svc->action == GB_SVC_WATCHDOG_BITE_PANIC_KERNEL) {
87 panic("SVC is not responding\n");
88 } else if (svc->action == GB_SVC_WATCHDOG_BITE_RESET_UNIPRO) {
89 dev_err(&svc->dev, "Resetting the greybus network, watch out!!!\n");
91 INIT_DELAYED_WORK(&reset_work, greybus_reset);
92 schedule_delayed_work(&reset_work, HZ / 2);
95 * Disable ourselves, we don't want to trip again unless
96 * userspace wants us to.
98 watchdog->enabled = false;
102 /* resubmit our work to happen again, if we are still "alive" */
103 if (watchdog->enabled)
104 schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
107 int gb_svc_watchdog_create(struct gb_svc *svc)
109 struct gb_svc_watchdog *watchdog;
115 watchdog = kmalloc(sizeof(*watchdog), GFP_KERNEL);
119 watchdog->enabled = false;
121 INIT_DELAYED_WORK(&watchdog->work, do_work);
122 svc->watchdog = watchdog;
124 watchdog->pm_notifier.notifier_call = svc_watchdog_pm_notifier;
125 retval = register_pm_notifier(&watchdog->pm_notifier);
127 dev_err(&svc->dev, "error registering pm notifier(%d)\n",
129 goto svc_watchdog_create_err;
132 retval = gb_svc_watchdog_enable(svc);
134 dev_err(&svc->dev, "error enabling watchdog (%d)\n", retval);
135 unregister_pm_notifier(&watchdog->pm_notifier);
136 goto svc_watchdog_create_err;
140 svc_watchdog_create_err:
141 svc->watchdog = NULL;
147 void gb_svc_watchdog_destroy(struct gb_svc *svc)
149 struct gb_svc_watchdog *watchdog = svc->watchdog;
154 unregister_pm_notifier(&watchdog->pm_notifier);
155 gb_svc_watchdog_disable(svc);
156 svc->watchdog = NULL;
160 bool gb_svc_watchdog_enabled(struct gb_svc *svc)
162 if (!svc || !svc->watchdog)
164 return svc->watchdog->enabled;
167 int gb_svc_watchdog_enable(struct gb_svc *svc)
169 struct gb_svc_watchdog *watchdog;
174 watchdog = svc->watchdog;
175 if (watchdog->enabled)
178 watchdog->enabled = true;
179 schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
183 int gb_svc_watchdog_disable(struct gb_svc *svc)
185 struct gb_svc_watchdog *watchdog;
190 watchdog = svc->watchdog;
191 if (!watchdog->enabled)
194 watchdog->enabled = false;
195 cancel_delayed_work_sync(&watchdog->work);