drm/exynos: fence: add dma fence support

This patch adds DMA fence based DMABUF synchronization feature.
The original codes of this feature is a below repository,
    https://chromium.googlesource.com/chromiumos/third_party/kernel
     chromeos-3.14

Change-Id: I4bcefb1487d6a85530fcd5ea4dde5fba435bb827
Signed-off-by: Inki Dae <inki.dae@samsung.com>
[squashed with bugfixes and ported to v4.1 Tizen kernel]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

5 files changed, 154 insertions, 0 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c
index 00c62fdd00b9..9046b0df9026 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
@@ -17,6 +17,7 @@
 #include <drm/drm_crtc_helper.h>
 
 #include <linux/component.h>
+#include <linux/fence.h>
 
 #include <drm/exynos_drm.h>
 
@@ -52,6 +53,9 @@ static int exynos_drm_load(struct drm_device *dev, unsigned long flags)
 	dev_set_drvdata(dev->dev, dev);
 	dev->dev_private = (void *)private;
 
+	private->gem_fence_context = fence_context_alloc(1);
+	atomic_set(&private->gem_fence_seqno, 0);
+
 	/*
 	 * create mapping to manage iommu table and set a pointer to iommu
 	 * mapping structure to iommu_mapping of private data.
diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.h b/drivers/gpu/drm/exynos/exynos_drm_drv.h
index e3377204f192..1b94bd02199e 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.h
@@ -16,7 +16,9 @@
 #define _EXYNOS_DRM_DRV_H_
 
 #include <drm/drmP.h>
+#include <drm/drm_sync_helper.h>
 #include <linux/module.h>
+#include <linux/dma-buf.h>
 
 #define MAX_CRTC	3
 #define MAX_PLANE	5
@@ -110,6 +112,17 @@ struct exynos_drm_plane {
 
 	bool enabled:1;
 	bool resume:1;
+	bool update_pending:1;
+
+#ifdef CONFIG_DRM_DMA_SYNC
+	unsigned fence_context;
+	atomic_t fence_seqno;
+	struct fence *fence;
+	struct drm_reservation_cb rcb;
+
+	struct fence *pending_fence;
+	bool pending_needs_vblank;
+#endif
 };
 
 /*
@@ -262,6 +275,9 @@ struct exynos_drm_private {
 	unsigned long da_space_size;
 
 	unsigned int pipe;
+
+	unsigned gem_fence_context;
+	atomic_t gem_fence_seqno;
 };
 
 /*
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.c b/drivers/gpu/drm/exynos/exynos_drm_fb.c
index 142eb4e3f59e..9e6ed44caae9 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fb.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fb.c
@@ -254,6 +254,22 @@ struct exynos_drm_gem_buf *exynos_drm_fb_buffer(struct drm_framebuffer *fb,
 	return buffer;
 }
 
+struct exynos_drm_gem_obj *exynos_drm_fb_gem_obj(struct drm_framebuffer *fb,
+								 int index)
+{
+	struct exynos_drm_fb *exynos_fb = to_exynos_fb(fb);
+	struct exynos_drm_gem_obj *obj;
+
+	if (index >= MAX_FB_BUFFER)
+		return ERR_PTR(-EINVAL);
+
+	obj = exynos_fb->exynos_gem_obj[index];
+	if (!obj)
+		return ERR_PTR(-EFAULT);
+
+	return obj;
+}
+
 static void exynos_drm_output_poll_changed(struct drm_device *dev)
 {
 	struct exynos_drm_private *private = dev->dev_private;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.h b/drivers/gpu/drm/exynos/exynos_drm_fb.h
index 517471b37566..12bb1c40d8a9 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fb.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_fb.h
@@ -32,4 +32,8 @@ void exynos_drm_fb_set_buf_cnt(struct drm_framebuffer *fb,
 /* get a buffer count to drm framebuffer. */
 unsigned int exynos_drm_fb_get_buf_cnt(struct drm_framebuffer *fb);
 
+/* get a gem object corresponding to a given index. */
+struct exynos_drm_gem_obj *exynos_drm_fb_gem_obj(struct drm_framebuffer *fb,
+								 int index);
+
 #endif
diff --git a/drivers/gpu/drm/exynos/exynos_drm_plane.c b/drivers/gpu/drm/exynos/exynos_drm_plane.c
index 3272ed60367e..979108a52dcc 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_plane.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_plane.c
@@ -138,6 +138,91 @@ void exynos_plane_mode_set(struct drm_plane *plane, struct drm_crtc *crtc,
 	plane->crtc = crtc;
 }
 
+#ifdef CONFIG_DRM_DMA_SYNC
+static void exynos_plane_update_cb(struct drm_reservation_cb *rcb, void *params)
+{
+	struct exynos_drm_plane *exynos_plane = params;
+	struct exynos_drm_crtc *exynos_crtc =
+					to_exynos_crtc(exynos_plane->base.crtc);
+
+	if (exynos_crtc->ops->win_commit)
+		exynos_crtc->ops->win_commit(exynos_crtc,
+					     exynos_plane->zpos);
+
+	exynos_plane->update_pending = false;
+
+	if (exynos_plane->pending_fence) {
+		drm_fence_signal_and_put(&exynos_plane->fence);
+		exynos_plane->fence = exynos_plane->pending_fence;
+		exynos_plane->pending_fence = NULL;
+	}
+
+	/* TODO */
+}
+#endif
+
+#ifdef CONFIG_DRM_DMA_SYNC
+static int exynos_plane_fence(struct exynos_drm_plane *plane,
+			      struct exynos_drm_gem_obj *obj)
+{
+	struct drm_crtc *crtc = plane->base.crtc;
+	struct exynos_drm_crtc *exynos_crtc;
+	struct reservation_object *resv;
+	struct fence *fence;
+	int ret;
+
+	exynos_crtc = to_exynos_crtc(crtc);
+	resv = obj->base.dma_buf->resv;
+
+	ww_mutex_lock(&resv->lock, NULL);
+
+	ret = reservation_object_reserve_shared(resv);
+	if (ret < 0) {
+		DRM_ERROR("Reserving space for shared fence failed: %d\n", ret);
+		goto err_mutex;
+	}
+
+	fence = drm_sw_fence_new(plane->fence_context,
+				 atomic_add_return(1, &plane->fence_seqno));
+	if (IS_ERR(fence)) {
+		ret = PTR_ERR(fence);
+		DRM_ERROR("Failed to create fence: %d\n", ret);
+		goto err_mutex;
+	}
+
+	plane->update_pending = true;
+	plane->pending_fence = fence;
+
+	reservation_object_add_shared_fence(resv, plane->pending_fence);
+
+	if (!reservation_object_test_signaled_rcu(resv, false)) {
+		drm_reservation_cb_init(&plane->rcb, exynos_plane_update_cb, plane);
+		ret = drm_reservation_cb_add(&plane->rcb, resv, false);
+		if (ret < 0) {
+			DRM_ERROR("Adding reservation to callback failed: %d\n", ret);
+			goto err_fence;
+		}
+
+		drm_reservation_cb_done(&plane->rcb);
+	} else {
+		exynos_plane_update_cb(&plane->rcb, plane);
+	}
+
+	ww_mutex_unlock(&resv->lock);
+
+	return 0;
+
+err_fence:
+	fence_put(plane->pending_fence);
+	plane->pending_fence = NULL;
+	plane->update_pending = false;
+err_mutex:
+	ww_mutex_unlock(&resv->lock);
+
+	return ret;
+}
+#endif
+
 int
 exynos_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 		     struct drm_framebuffer *fb, int crtc_x, int crtc_y,
@@ -148,8 +233,12 @@ exynos_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 
 	struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
 	struct exynos_drm_plane *exynos_plane = to_exynos_plane(plane);
+	struct exynos_drm_gem_obj *obj;
 	int ret;
 
+	if (exynos_plane->update_pending)
+		return -EBUSY;
+
 	ret = exynos_check_plane(plane, fb);
 	if (ret < 0)
 		return ret;
@@ -158,10 +247,28 @@ exynos_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 			      crtc_w, crtc_h, src_x >> 16, src_y >> 16,
 			      src_w >> 16, src_h >> 16);
 
+	obj = exynos_drm_fb_gem_obj(fb, 0);
+	if (IS_ERR(obj)) {
+		/* there should be no a such case. */
+		WARN_ON(1);
+		return PTR_ERR(obj);
+	}
+
+#ifdef CONFIG_DRM_DMA_SYNC
+	if (!obj->base.dma_buf || !obj->base.dma_buf->resv) {
+		if (exynos_crtc->ops->win_commit)
+			exynos_crtc->ops->win_commit(exynos_crtc,
+						     exynos_plane->zpos);
+		return 0;
+	}
+
+	return exynos_plane_fence(exynos_plane, obj);
+#else
 	if (exynos_crtc->ops->win_commit)
 		exynos_crtc->ops->win_commit(exynos_crtc, exynos_plane->zpos);
 
 	return 0;
+#endif
 }
 
 static int exynos_disable_plane(struct drm_plane *plane)
@@ -169,6 +276,8 @@ static int exynos_disable_plane(struct drm_plane *plane)
 	struct exynos_drm_plane *exynos_plane = to_exynos_plane(plane);
 	struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(plane->crtc);
 
+	exynos_plane->update_pending = false;
+
 	if (exynos_crtc && exynos_crtc->ops->win_disable)
 		exynos_crtc->ops->win_disable(exynos_crtc,
 					      exynos_plane->zpos);
@@ -222,5 +331,10 @@ int exynos_plane_init(struct drm_device *dev,
 
 	exynos_plane_attach_zpos_property(&exynos_plane->base, zpos);
 
+#ifdef CONFIG_DRM_DMA_SYNC
+	exynos_plane->fence_context = fence_context_alloc(1);
+	atomic_set(&exynos_plane->fence_seqno, 0);
+#endif
+
 	return 0;
 }