[RFC PATCH v2 9/9] drm: mali-dp: Add writeback out-fence support

[Brian Starkey]

If userspace has asked for an out-fence for the writeback, we add a
fence to malidp_mw_job, to be signaled when the writeback job has
completed.

Signed-off-by: Brian Starkey <brian.starkey at arm.com>
---
 drivers/gpu/drm/arm/malidp_hw.c |    5 ++++-
 drivers/gpu/drm/arm/malidp_mw.c |   18 +++++++++++++++++-
 drivers/gpu/drm/arm/malidp_mw.h |    3 +++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/arm/malidp_hw.c b/drivers/gpu/drm/arm/malidp_hw.c
index 1689547..3032226 100644
--- a/drivers/gpu/drm/arm/malidp_hw.c
+++ b/drivers/gpu/drm/arm/malidp_hw.c
@@ -707,8 +707,11 @@ static irqreturn_t malidp_se_irq(int irq, void *arg)
                unsigned long irqflags;
                /*
                 * We can't unreference the framebuffer here, so we queue it
-                * up on our threaded handler.
+                * up on our threaded handler. However, signal the fence
+                * as soon as possible
                 */
+               malidp_mw_job_signal(drm, malidp->current_mw, 0);
+
                spin_lock_irqsave(&malidp->mw_lock, irqflags);
                list_add_tail(&malidp->current_mw->list,
                              &malidp->finished_mw_jobs);
diff --git a/drivers/gpu/drm/arm/malidp_mw.c b/drivers/gpu/drm/arm/malidp_mw.c
index 69e423c..05880b1 100644
--- a/drivers/gpu/drm/arm/malidp_mw.c
+++ b/drivers/gpu/drm/arm/malidp_mw.c
@@ -34,11 +34,24 @@ struct malidp_mw_connector_state {
        u8 n_planes;
 };

+void malidp_mw_job_signal(struct drm_device *drm,
+                         struct malidp_mw_job *job, int status)
+{
+       DRM_DEV_DEBUG_DRIVER(drm->dev, "MW job signal %p\n", job);
+
+       if (!job->fence)
+               return;
+
+       job->fence->status = status;
+       fence_signal(job->fence);
+}
+
 void malidp_mw_job_cleanup(struct drm_device *drm,
                                  struct malidp_mw_job *job)
 {
        DRM_DEV_DEBUG_DRIVER(drm->dev, "MW job cleanup %p\n", job);
        drm_framebuffer_unreference(job->fb);
+       fence_put(job->fence);
        kfree(job);
 }

@@ -107,8 +120,10 @@ static void malidp_mw_connector_destroy_state(struct 
drm_connector *connector,
        struct malidp_mw_connector_state *mw_state = to_mw_state(state);

        __drm_atomic_helper_connector_destroy_state(&mw_state->base);
-       if (mw_state->job)
+       if (mw_state->job) {
+               malidp_mw_job_signal(connector->dev, mw_state->job, -EPIPE);
                malidp_mw_job_cleanup(connector->dev, mw_state->job);
+       }
        kfree(mw_state);
 }

@@ -177,6 +192,7 @@ malidp_mw_encoder_atomic_check(struct drm_encoder *encoder,
        /* We can take ownership of the framebuffer reference in the job. */
        mw_state->job->fb = conn_state->fb;
        conn_state->fb = NULL;
+       mw_state->job->fence = fence_get(conn_state->out_fence);

        return 0;
 }
diff --git a/drivers/gpu/drm/arm/malidp_mw.h b/drivers/gpu/drm/arm/malidp_mw.h
index db7b2b0..5d0bd1d 100644
--- a/drivers/gpu/drm/arm/malidp_mw.h
+++ b/drivers/gpu/drm/arm/malidp_mw.h
@@ -15,11 +15,14 @@
 struct malidp_mw_job {
        struct list_head list;
        struct drm_framebuffer *fb;
+       struct fence *fence;
 };

 int malidp_mw_connector_init(struct drm_device *drm);
 void malidp_mw_atomic_commit(struct drm_device *drm,
                             struct drm_atomic_state *old_state);
+void malidp_mw_job_signal(struct drm_device *drm,
+                         struct malidp_mw_job *job, int status);
 void malidp_mw_job_cleanup(struct drm_device *drm,
                                  struct malidp_mw_job *job);
 #endif
-- 
1.7.9.5