[PATCH 7/8] drm/panthor: Add sync_update eventfd handling

[Mihail Atanassov]

Expose the SYNC_UPDATE event to userspace so it can respond to changes
in syncobj state.

Signed-off-by: Mihail Atanassov <mihail.atanas...@arm.com>
---
 drivers/gpu/drm/panthor/panthor_sched.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panthor/panthor_sched.c 
b/drivers/gpu/drm/panthor/panthor_sched.c
index 92172b2c6253..67c27fcc3345 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/drivers/gpu/drm/panthor/panthor_sched.c
@@ -643,6 +643,9 @@ struct panthor_group {
         * panthor_group::groups::waiting list.
         */
        struct list_head wait_node;
+
+       /** @eventfd_sync_update_ctx: eventfd context to signal on 
GPU_SYNC_UPDATE */
+       struct eventfd_ctx *eventfd_sync_update_ctx;
 };
 
 /**
@@ -797,6 +800,10 @@ static void group_release_work(struct work_struct *work)
        panthor_kernel_bo_destroy(group->syncobjs);
 
        panthor_vm_put(group->vm);
+
+       if (group->eventfd_sync_update_ctx)
+               eventfd_ctx_put(group->eventfd_sync_update_ctx);
+
        kfree(group);
 }
 
@@ -1501,6 +1508,9 @@ static void csg_slot_sync_update_locked(struct 
panthor_device *ptdev,
                /* Rerun XGS jobs immediately, as this can potentially unblock 
the group */
                panthor_xgs_queue_pool_recheck(group->pfile);
 
+               if (group->eventfd_sync_update_ctx)
+                       eventfd_signal(group->eventfd_sync_update_ctx);
+
                if (!group->user_submit)
                        group_queue_work(group, sync_upd);
        }
@@ -3204,9 +3214,18 @@ int panthor_group_create(struct panthor_file *pfile,
        INIT_WORK(&group->tiler_oom_work, group_tiler_oom_work);
        INIT_WORK(&group->release_work, group_release_work);
 
-       if (group_args->flags & DRM_PANTHOR_GROUP_CREATE_USER_SUBMIT)
+       if (group_args->flags & DRM_PANTHOR_GROUP_CREATE_USER_SUBMIT) {
                group->user_submit = true;
 
+               if (group_args->eventfd_sync_update >= 0) {
+                       group->eventfd_sync_update_ctx = eventfd_ctx_fdget(
+                               group_args->eventfd_sync_update);
+                       ret = PTR_ERR_OR_ZERO(group->eventfd_sync_update_ctx);
+                       if (ret)
+                               goto err_put_group;
+               }
+       }
+
        group->vm = panthor_vm_pool_get_vm(pfile->vms, group_args->vm_id);
        if (!group->vm) {
                ret = -EINVAL;
-- 
2.45.0