Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 197 insertions, 0 deletions

diff --git a/drivers/greybus/svc_watchdog.c b/drivers/greybus/svc_watchdog.c
new file mode 100644
index 0000000000..b6b1682c19
--- /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;
+}