Add virtio gpu driver.

This patch adds a kms driver for the virtio gpu.  The xorg modesetting
driver can handle the device just fine, the framebuffer for fbcon is
there too.

Qemu patches for the host side are under review currently.

The pci version of the device comes in two variants: with and without
vga compatibility.  The former has a extra memory bar for the vga
framebuffer, the later is a pure virtio device.  The only concern for
this driver is that in the virtio-vga case we have to kick out the
firmware framebuffer.

Initial revision has only 2d support, 3d (virgl) support requires
some more work on the qemu side and will be added later.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 173 insertions, 0 deletions

diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
new file mode 100644
index 000000000000..132405f15389
--- /dev/null
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -0,0 +1,173 @@
+/*
+ * Copyright (C) 2015 Red Hat, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <drm/drmP.h>
+#include "virtgpu_drv.h"
+
+static int virtio_gpu_fbdev = 1;
+
+MODULE_PARM_DESC(fbdev, "Disable/Enable framebuffer device & console");
+module_param_named(fbdev, virtio_gpu_fbdev, int, 0400);
+
+static void virtio_gpu_config_changed_work_func(struct work_struct *work)
+{
+	struct virtio_gpu_device *vgdev =
+		container_of(work, struct virtio_gpu_device,
+			     config_changed_work);
+	u32 events_read, events_clear = 0;
+
+	/* read the config space */
+	virtio_cread(vgdev->vdev, struct virtio_gpu_config,
+		     events_read, &events_read);
+	if (events_read & VIRTIO_GPU_EVENT_DISPLAY) {
+		virtio_gpu_cmd_get_display_info(vgdev);
+		drm_helper_hpd_irq_event(vgdev->ddev);
+		events_clear |= VIRTIO_GPU_EVENT_DISPLAY;
+	}
+	virtio_cwrite(vgdev->vdev, struct virtio_gpu_config,
+		      events_clear, &events_clear);
+}
+
+static void virtio_gpu_init_vq(struct virtio_gpu_queue *vgvq,
+			       void (*work_func)(struct work_struct *work))
+{
+	spin_lock_init(&vgvq->qlock);
+	init_waitqueue_head(&vgvq->ack_queue);
+	INIT_WORK(&vgvq->dequeue_work, work_func);
+}
+
+int virtio_gpu_driver_load(struct drm_device *dev, unsigned long flags)
+{
+	static vq_callback_t *callbacks[] = {
+		virtio_gpu_ctrl_ack, virtio_gpu_cursor_ack
+	};
+	static const char *names[] = { "control", "cursor" };
+
+	struct virtio_gpu_device *vgdev;
+	/* this will expand later */
+	struct virtqueue *vqs[2];
+	u32 num_scanouts;
+	int ret;
+
+	if (!virtio_has_feature(dev->virtdev, VIRTIO_F_VERSION_1))
+		return -ENODEV;
+
+	vgdev = kzalloc(sizeof(struct virtio_gpu_device), GFP_KERNEL);
+	if (!vgdev)
+		return -ENOMEM;
+
+	vgdev->ddev = dev;
+	dev->dev_private = vgdev;
+	vgdev->vdev = dev->virtdev;
+	vgdev->dev = dev->dev;
+
+	spin_lock_init(&vgdev->display_info_lock);
+	spin_lock_init(&vgdev->ctx_id_idr_lock);
+	idr_init(&vgdev->ctx_id_idr);
+	spin_lock_init(&vgdev->resource_idr_lock);
+	idr_init(&vgdev->resource_idr);
+	init_waitqueue_head(&vgdev->resp_wq);
+	virtio_gpu_init_vq(&vgdev->ctrlq, virtio_gpu_dequeue_ctrl_func);
+	virtio_gpu_init_vq(&vgdev->cursorq, virtio_gpu_dequeue_cursor_func);
+
+	spin_lock_init(&vgdev->fence_drv.lock);
+	INIT_LIST_HEAD(&vgdev->fence_drv.fences);
+	INIT_WORK(&vgdev->config_changed_work,
+		  virtio_gpu_config_changed_work_func);
+
+	ret = vgdev->vdev->config->find_vqs(vgdev->vdev, 2, vqs,
+					    callbacks, names);
+	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");
+		goto err_vbufs;
+	}
+
+	ret = virtio_gpu_ttm_init(vgdev);
+	if (ret) {
+		DRM_ERROR("failed to init ttm %d\n", ret);
+		goto err_ttm;
+	}
+
+	/* get display info */
+	virtio_cread(vgdev->vdev, struct virtio_gpu_config,
+		     num_scanouts, &num_scanouts);
+	vgdev->num_scanouts = min_t(uint32_t, num_scanouts,
+				    VIRTIO_GPU_MAX_SCANOUTS);
+	if (!vgdev->num_scanouts) {
+		DRM_ERROR("num_scanouts is zero\n");
+		ret = -EINVAL;
+		goto err_scanouts;
+	}
+
+	ret = virtio_gpu_modeset_init(vgdev);
+	if (ret)
+		goto err_modeset;
+
+	virtio_device_ready(vgdev->vdev);
+	vgdev->vqs_ready = true;
+
+	if (virtio_gpu_fbdev)
+		virtio_gpu_fbdev_init(vgdev);
+	virtio_gpu_cmd_get_display_info(vgdev);
+
+	return 0;
+
+err_modeset:
+err_scanouts:
+	virtio_gpu_ttm_fini(vgdev);
+err_ttm:
+	virtio_gpu_free_vbufs(vgdev);
+err_vbufs:
+	vgdev->vdev->config->del_vqs(vgdev->vdev);
+err_vqs:
+	kfree(vgdev);
+	return ret;
+}
+
+int virtio_gpu_driver_unload(struct drm_device *dev)
+{
+	struct virtio_gpu_device *vgdev = dev->dev_private;
+
+	vgdev->vqs_ready = false;
+	flush_work(&vgdev->ctrlq.dequeue_work);
+	flush_work(&vgdev->cursorq.dequeue_work);
+	flush_work(&vgdev->config_changed_work);
+	vgdev->vdev->config->del_vqs(vgdev->vdev);
+
+	virtio_gpu_modeset_fini(vgdev);
+	virtio_gpu_ttm_fini(vgdev);
+	virtio_gpu_free_vbufs(vgdev);
+	kfree(vgdev);
+	return 0;
+}