virtio_mmio: pm: Add notification handlers for restore and freeze

Handle restore and freeze notifications from the PM core. Expose
these to individual virtio drivers that can quiesce and resume vq
operations.

Signed-off-by: Yurii Danilovskyi <glyd@opensynergy.com>
Signed-off-by: Mikhail Golubev <Mikhail.Golubev@opensynergy.com>

drivers/virtio/virtio_mmio.c

@@ -762,6 +762,24 @@ static void vm_unregister_cmdline_devices(void)
 
 #endif
 
+static int __maybe_unused virtio_mmio_freeze(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
+
+	return virtio_device_freeze(&vm_dev->vdev);
+}
+
+static int __maybe_unused virtio_mmio_restore(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
+
+	return virtio_device_restore(&vm_dev->vdev);
+}
+
+static SIMPLE_DEV_PM_OPS(virtio_mmio_pm_ops, virtio_mmio_freeze, virtio_mmio_restore);
+
 /* Platform driver */
 
 static const struct of_device_id virtio_mmio_match[] = {
@@ -785,6 +803,7 @@ static struct platform_driver virtio_mmio_driver = {
 		.name	= "virtio-mmio",
 		.of_match_table	= virtio_mmio_match,
 		.acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match),
+		.pm = &virtio_mmio_pm_ops,
 	},
 };