Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/greybus/svc_watchdog.c b/drivers/greybus/svc_watchdog.c
new file mode 100644
index 0000000..b6b1682
--- /dev/null
+++ b/drivers/greybus/svc_watchdog.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SVC Greybus "watchdog" driver.
+ *
+ * Copyright 2016 Google Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/suspend.h>
+#include <linux/workqueue.h>
+#include <linux/greybus.h>
+
+#define SVC_WATCHDOG_PERIOD (2 * HZ)
+
+struct gb_svc_watchdog {
+ struct delayed_work work;
+ struct gb_svc *svc;
+ bool enabled;
+ struct notifier_block pm_notifier;
+};
+
+static struct delayed_work reset_work;
+
+static int svc_watchdog_pm_notifier(struct notifier_block *notifier,
+ unsigned long pm_event, void *unused)
+{
+ struct gb_svc_watchdog *watchdog =
+ container_of(notifier, struct gb_svc_watchdog, pm_notifier);
+
+ switch (pm_event) {
+ case PM_SUSPEND_PREPARE:
+ gb_svc_watchdog_disable(watchdog->svc);
+ break;
+ case PM_POST_SUSPEND:
+ gb_svc_watchdog_enable(watchdog->svc);
+ break;
+ default:
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static void greybus_reset(struct work_struct *work)
+{
+ static char const start_path[] = "/system/bin/start";
+ static char *envp[] = {
+ "HOME=/",
+ "PATH=/sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin",
+ NULL,
+ };
+ static char *argv[] = {
+ (char *)start_path,
+ "unipro_reset",
+ NULL,
+ };
+
+ pr_err("svc_watchdog: calling \"%s %s\" to reset greybus network!\n",
+ argv[0], argv[1]);
+ call_usermodehelper(start_path, argv, envp, UMH_WAIT_EXEC);
+}
+
+static void do_work(struct work_struct *work)
+{
+ struct gb_svc_watchdog *watchdog;
+ struct gb_svc *svc;
+ int retval;
+
+ watchdog = container_of(work, struct gb_svc_watchdog, work.work);
+ svc = watchdog->svc;
+
+ dev_dbg(&svc->dev, "%s: ping.\n", __func__);
+ retval = gb_svc_ping(svc);
+ if (retval) {
+ /*
+ * Something went really wrong, let's warn userspace and then
+ * pull the plug and reset the whole greybus network.
+ * We need to do this outside of this workqueue as we will be
+ * tearing down the svc device itself. So queue up
+ * yet-another-callback to do that.
+ */
+ dev_err(&svc->dev,
+ "SVC ping has returned %d, something is wrong!!!\n",
+ retval);
+
+ if (svc->action == GB_SVC_WATCHDOG_BITE_PANIC_KERNEL) {
+ panic("SVC is not responding\n");
+ } else if (svc->action == GB_SVC_WATCHDOG_BITE_RESET_UNIPRO) {
+ dev_err(&svc->dev, "Resetting the greybus network, watch out!!!\n");
+
+ INIT_DELAYED_WORK(&reset_work, greybus_reset);
+ schedule_delayed_work(&reset_work, HZ / 2);
+
+ /*
+ * Disable ourselves, we don't want to trip again unless
+ * userspace wants us to.
+ */
+ watchdog->enabled = false;
+ }
+ }
+
+ /* resubmit our work to happen again, if we are still "alive" */
+ if (watchdog->enabled)
+ schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
+}
+
+int gb_svc_watchdog_create(struct gb_svc *svc)
+{
+ struct gb_svc_watchdog *watchdog;
+ int retval;
+
+ if (svc->watchdog)
+ return 0;
+
+ watchdog = kmalloc(sizeof(*watchdog), GFP_KERNEL);
+ if (!watchdog)
+ return -ENOMEM;
+
+ watchdog->enabled = false;
+ watchdog->svc = svc;
+ INIT_DELAYED_WORK(&watchdog->work, do_work);
+ svc->watchdog = watchdog;
+
+ watchdog->pm_notifier.notifier_call = svc_watchdog_pm_notifier;
+ retval = register_pm_notifier(&watchdog->pm_notifier);
+ if (retval) {
+ dev_err(&svc->dev, "error registering pm notifier(%d)\n",
+ retval);
+ goto svc_watchdog_create_err;
+ }
+
+ retval = gb_svc_watchdog_enable(svc);
+ if (retval) {
+ dev_err(&svc->dev, "error enabling watchdog (%d)\n", retval);
+ unregister_pm_notifier(&watchdog->pm_notifier);
+ goto svc_watchdog_create_err;
+ }
+ return retval;
+
+svc_watchdog_create_err:
+ svc->watchdog = NULL;
+ kfree(watchdog);
+
+ return retval;
+}
+
+void gb_svc_watchdog_destroy(struct gb_svc *svc)
+{
+ struct gb_svc_watchdog *watchdog = svc->watchdog;
+
+ if (!watchdog)
+ return;
+
+ unregister_pm_notifier(&watchdog->pm_notifier);
+ gb_svc_watchdog_disable(svc);
+ svc->watchdog = NULL;
+ kfree(watchdog);
+}
+
+bool gb_svc_watchdog_enabled(struct gb_svc *svc)
+{
+ if (!svc || !svc->watchdog)
+ return false;
+ return svc->watchdog->enabled;
+}
+
+int gb_svc_watchdog_enable(struct gb_svc *svc)
+{
+ struct gb_svc_watchdog *watchdog;
+
+ if (!svc->watchdog)
+ return -ENODEV;
+
+ watchdog = svc->watchdog;
+ if (watchdog->enabled)
+ return 0;
+
+ watchdog->enabled = true;
+ schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
+ return 0;
+}
+
+int gb_svc_watchdog_disable(struct gb_svc *svc)
+{
+ struct gb_svc_watchdog *watchdog;
+
+ if (!svc->watchdog)
+ return -ENODEV;
+
+ watchdog = svc->watchdog;
+ if (!watchdog->enabled)
+ return 0;
+
+ watchdog->enabled = false;
+ cancel_delayed_work_sync(&watchdog->work);
+ return 0;
+}