[PATCH v6 5/6] drm/fence: add fence timeline to drm_crtc

[Gustavo Padovan <gustavo@padovan.org>]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Create one timeline context for each CRTC to be able to handle out-fences
and signal them. It adds a few members to struct drm_crtc: fence_context,
where we store the context we get from fence_context_alloc(), the
fence seqno and the fence lock, that we pass in fence_init() to be
used by the fence.

v2: Comment by Daniel Stone:
	- add BUG_ON() to fence_to_crtc() macro

v3: Comment by Ville Syrjälä
	- Use more meaningful name as crtc timeline name

v4: Comments by Brian Starkey
	- Use even more meaninful name for the crtc timeline
	- add doc for timeline_name
    Comment by Daniel Vetter
	- use in-line style for comments

    - rebase after fence -> dma_fence rename

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
---
 drivers/gpu/drm/drm_crtc.c | 31 +++++++++++++++++++++++++++++++
 include/drm/drm_crtc.h     | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 7878bfd..e2a06c8 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -165,6 +165,32 @@ static void drm_crtc_crc_fini(struct drm_crtc *crtc)
 #endif
 }
 
+static const char *drm_crtc_fence_get_driver_name(struct dma_fence *fence)
+{
+	struct drm_crtc *crtc = fence_to_crtc(fence);
+
+	return crtc->dev->driver->name;
+}
+
+static const char *drm_crtc_fence_get_timeline_name(struct dma_fence *fence)
+{
+	struct drm_crtc *crtc = fence_to_crtc(fence);
+
+	return crtc->timeline_name;
+}
+
+static bool drm_crtc_fence_enable_signaling(struct dma_fence *fence)
+{
+	return true;
+}
+
+const struct dma_fence_ops drm_crtc_fence_ops = {
+	.get_driver_name = drm_crtc_fence_get_driver_name,
+	.get_timeline_name = drm_crtc_fence_get_timeline_name,
+	.enable_signaling = drm_crtc_fence_enable_signaling,
+	.wait = dma_fence_default_wait,
+};
+
 /**
  * drm_crtc_init_with_planes - Initialise a new CRTC object with
  *    specified primary and cursor planes.
@@ -222,6 +248,11 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 		return -ENOMEM;
 	}
 
+	crtc->fence_context = dma_fence_context_alloc(1);
+	spin_lock_init(&crtc->fence_lock);
+	snprintf(crtc->timeline_name, sizeof(crtc->timeline_name),
+		 "CRTC:%d-%s", crtc->base.id, crtc->name);
+
 	crtc->base.properties = &crtc->properties;
 
 	list_add_tail(&crtc->head, &config->crtc_list);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 719b6a8..278dbdd 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -32,6 +32,8 @@
 #include <linux/fb.h>
 #include <linux/hdmi.h>
 #include <linux/media-bus-format.h>
+#include <linux/srcu.h>
+#include <linux/dma-fence.h>
 #include <uapi/drm/drm_mode.h>
 #include <uapi/drm/drm_fourcc.h>
 #include <drm/drm_modeset_lock.h>
@@ -726,8 +728,45 @@ struct drm_crtc {
 	 */
 	struct drm_crtc_crc crc;
 #endif
+
+	/**
+	 * @fence_context:
+	 *
+	 * timeline context used for fence operations.
+	 */
+	unsigned int fence_context;
+
+	/**
+	 * @fence_lock:
+	 *
+	 * spinlock to protect the fences in the fence_context.
+	 */
+
+	spinlock_t fence_lock;
+	/**
+	 * @fence_seqno:
+	 *
+	 * Seqno variable used as monotonic counter for the fences
+	 * created on the CRTC's timeline.
+	 */
+	unsigned long fence_seqno;
+
+	/**
+	 * @timeline_name:
+	 *
+	 * The name of the CRTC's fence timeline.
+	 */
+	char timeline_name[32];
 };
 
+extern const struct dma_fence_ops drm_crtc_fence_ops;
+
+static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
+{
+	BUG_ON(fence->ops != &drm_crtc_fence_ops);
+	return container_of(fence->lock, struct drm_crtc, fence_lock);
+}
+
 /**
  * struct drm_mode_set - new values for a CRTC config change
  * @fb: framebuffer to use for new config
-- 
2.5.5