mac802154: cfg: add suspend and resume callbacks

This patch introduces suspend and resume callbacks to mac802154. When
doing suspend we calling the stop driver callback which should stop the
receiving of frames. A transceiver should go into low-power mode then.
Calling resume will call the start driver callback, which starts receiving
again and allow to transmit frames.

This was tested only with the fakelb driver and a qemu vm by doing the
following commands:

echo "devices" > /sys/power/pm_test
echo "freeze" > /sys/power/state

while doing some high traffic between two fakelb phys.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/mac802154/cfg.c b/net/mac802154/cfg.c
index 44db861..f7ba51e 100644
--- a/net/mac802154/cfg.c
+++ b/net/mac802154/cfg.c
@@ -44,6 +44,49 @@
 	ieee802154_if_remove(sdata);
 }
 
+#ifdef CONFIG_PM
+static int ieee802154_suspend(struct wpan_phy *wpan_phy)
+{
+	struct ieee802154_local *local = wpan_phy_priv(wpan_phy);
+
+	if (!local->open_count)
+		goto suspend;
+
+	ieee802154_stop_queue(&local->hw);
+	synchronize_net();
+
+	/* stop hardware - this must stop RX */
+	ieee802154_stop_device(local);
+
+suspend:
+	local->suspended = true;
+	return 0;
+}
+
+static int ieee802154_resume(struct wpan_phy *wpan_phy)
+{
+	struct ieee802154_local *local = wpan_phy_priv(wpan_phy);
+	int ret;
+
+	/* nothing to do if HW shouldn't run */
+	if (!local->open_count)
+		goto wake_up;
+
+	/* restart hardware */
+	ret = drv_start(local);
+	if (ret)
+		return ret;
+
+wake_up:
+	ieee802154_wake_queue(&local->hw);
+	local->suspended = false;
+	return 0;
+}
+#else
+#define ieee802154_suspend NULL
+#define ieee802154_resume NULL
+#endif
+
 static int
 ieee802154_add_iface(struct wpan_phy *phy, const char *name,
 		     unsigned char name_assign_type,
@@ -232,6 +275,8 @@
 const struct cfg802154_ops mac802154_config_ops = {
 	.add_virtual_intf_deprecated = ieee802154_add_iface_deprecated,
 	.del_virtual_intf_deprecated = ieee802154_del_iface_deprecated,
+	.suspend = ieee802154_suspend,
+	.resume = ieee802154_resume,
 	.add_virtual_intf = ieee802154_add_iface,
 	.del_virtual_intf = ieee802154_del_iface,
 	.set_channel = ieee802154_set_channel,