[RFC PATCH 1/2] drm/virtio: freeze and restore hooks to support suspend and resume

[Dongwon Kim <dongwon.kim@xxxxxxxxx>]

virtqueue needs to be flushed and removed before VM goes into sleep or
hibernation then should be reinitialized again upon wake-up.

Cc: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Cc: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
Signed-off-by: Dongwon Kim <dongwon.kim@xxxxxxxxx>
---
 drivers/gpu/drm/virtio/virtgpu_drv.c | 53 +++++++++++++++++++++++++++-
 drivers/gpu/drm/virtio/virtgpu_drv.h |  1 +
 drivers/gpu/drm/virtio/virtgpu_kms.c | 22 ++++++++----
 3 files changed, 69 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 0035affc3e59..2738589a04e4 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -148,6 +148,53 @@ static unsigned int features[] = {
 	VIRTIO_GPU_F_RESOURCE_BLOB,
 	VIRTIO_GPU_F_CONTEXT_INIT,
 };
+
+#ifdef CONFIG_PM_SLEEP
+static int virtgpu_freeze(struct virtio_device *vdev)
+{
+	struct drm_device *dev = vdev->priv;
+	struct virtio_gpu_device *vgdev = dev->dev_private;
+	int error;
+
+	error = drm_mode_config_helper_suspend(dev);
+	if (error) {
+		DRM_ERROR("suspend error %d\n", error);
+		return error;
+	}
+
+	flush_work(&vgdev->obj_free_work);
+	flush_work(&vgdev->ctrlq.dequeue_work);
+	flush_work(&vgdev->cursorq.dequeue_work);
+	flush_work(&vgdev->config_changed_work);
+	vdev->config->del_vqs(vdev);
+
+	return 0;
+}
+
+static int virtgpu_restore(struct virtio_device *vdev)
+{
+	struct drm_device *dev = vdev->priv;
+	struct virtio_gpu_device *vgdev = dev->dev_private;
+	int error;
+
+	error = virtio_gpu_find_vqs(vgdev);
+	if (error) {
+		DRM_ERROR("failed to find virt queues\n");
+		return error;
+	}
+
+	virtio_device_ready(vdev);
+
+	error = drm_mode_config_helper_resume(dev);
+	if (error) {
+		DRM_ERROR("resume error %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+#endif
+
 static struct virtio_driver virtio_gpu_driver = {
 	.feature_table = features,
 	.feature_table_size = ARRAY_SIZE(features),
@@ -156,7 +203,11 @@ static struct virtio_driver virtio_gpu_driver = {
 	.id_table = id_table,
 	.probe = virtio_gpu_probe,
 	.remove = virtio_gpu_remove,
-	.config_changed = virtio_gpu_config_changed
+	.config_changed = virtio_gpu_config_changed,
+#ifdef CONFIG_PM_SLEEP
+	.freeze = virtgpu_freeze,
+	.restore = virtgpu_restore,
+#endif
 };
 
 module_virtio_driver(virtio_gpu_driver);
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 20a418f64533..646f7674a496 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -292,6 +292,7 @@ void virtio_gpu_deinit(struct drm_device *dev);
 void virtio_gpu_release(struct drm_device *dev);
 int virtio_gpu_driver_open(struct drm_device *dev, struct drm_file *file);
 void virtio_gpu_driver_postclose(struct drm_device *dev, struct drm_file *file);
+int virtio_gpu_find_vqs(struct virtio_gpu_device *vgdev);
 
 /* virtgpu_gem.c */
 int virtio_gpu_gem_object_open(struct drm_gem_object *obj,
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 27b7f14dae89..3a1d164eaf10 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -112,16 +112,28 @@ static void virtio_gpu_get_capsets(struct virtio_gpu_device *vgdev,
 	vgdev->num_capsets = num_capsets;
 }
 
-int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
+int virtio_gpu_find_vqs(struct virtio_gpu_device *vgdev)
 {
 	static vq_callback_t *callbacks[] = {
 		virtio_gpu_ctrl_ack, virtio_gpu_cursor_ack
 	};
 	static const char * const names[] = { "control", "cursor" };
+	struct virtqueue *vqs[2];
+	int ret;
+
+	ret = virtio_find_vqs(vgdev->vdev, 2, vqs, callbacks, names, NULL);
+	if (ret)
+		return ret;
+
+	vgdev->ctrlq.vq = vqs[0];
+	vgdev->cursorq.vq = vqs[1];
+
+	return 0;
+}
 
+int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
+{
 	struct virtio_gpu_device *vgdev;
-	/* this will expand later */
-	struct virtqueue *vqs[2];
 	u32 num_scanouts, num_capsets;
 	int ret = 0;
 
@@ -205,13 +217,11 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
 	DRM_INFO("features: %ccontext_init\n",
 		 vgdev->has_context_init ? '+' : '-');
 
-	ret = virtio_find_vqs(vgdev->vdev, 2, vqs, callbacks, names, NULL);
+	ret = virtio_gpu_find_vqs(vgdev);
 	if (ret) {
 		DRM_ERROR("failed to find virt queues\n");
 		goto err_vqs;
 	}
-	vgdev->ctrlq.vq = vqs[0];
-	vgdev->cursorq.vq = vqs[1];
 	ret = virtio_gpu_alloc_vbufs(vgdev);
 	if (ret) {
 		DRM_ERROR("failed to alloc vbufs\n");
-- 
2.20.1