drm/vc4: Expose dma-buf fences for V3D rendering.

This is needed for proper synchronization with display on another DRM
device (pl111 or tinydrm) with buffers produced by vc4 V3D.  Fixes the
new igt vc4_dmabuf_poll testcase, and rendering of one of the glmark2
desktop tests on pl111+vc4.

This doesn't yet introduce waits on another device's fences before
vc4's rendering/display, because I don't have testcases for them.

v2: Reuse dma_fence_free(), retitle commit message to clarify that
    it's not a full dma-buf fencing implementation yet.

Signed-off-by: Eric Anholt <eric@anholt.net>
Link: http://patchwork.freedesktop.org/patch/msgid/20170412191202.22740-6-eric@anholt.net
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_fence.c b/drivers/gpu/drm/vc4/vc4_fence.c
new file mode 100644
index 000000000000..dbf5a5a5d5f5
--- /dev/null
+++ b/drivers/gpu/drm/vc4/vc4_fence.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright © 2017 Broadcom
+ *
+ * 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 AUTHORS OR COPYRIGHT HOLDERS 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 "vc4_drv.h"
+
+static const char *vc4_fence_get_driver_name(struct dma_fence *fence)
+{
+	return "vc4";
+}
+
+static const char *vc4_fence_get_timeline_name(struct dma_fence *fence)
+{
+	return "vc4-v3d";
+}
+
+static bool vc4_fence_enable_signaling(struct dma_fence *fence)
+{
+	return true;
+}
+
+static bool vc4_fence_signaled(struct dma_fence *fence)
+{
+	struct vc4_fence *f = to_vc4_fence(fence);
+	struct vc4_dev *vc4 = to_vc4_dev(f->dev);
+
+	return vc4->finished_seqno >= f->seqno;
+}
+
+const struct dma_fence_ops vc4_fence_ops = {
+	.get_driver_name = vc4_fence_get_driver_name,
+	.get_timeline_name = vc4_fence_get_timeline_name,
+	.enable_signaling = vc4_fence_enable_signaling,
+	.signaled = vc4_fence_signaled,
+	.wait = dma_fence_default_wait,
+	.release = dma_fence_free,
+};