[RFC v1 5/9] drm/xe/hw_engine_group: Add helper to wait for dma fence jobs

[Francois Dugast]

This is a required feature for long running jobs not to be submitted
while dma fence jobs are running on the hw engine group.

Signed-off-by: Francois Dugast <francois.dugast at intel.com>
---
 drivers/gpu/drm/xe/xe_hw_engine.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_hw_engine.c b/drivers/gpu/drm/xe/xe_hw_engine.c
index 850f7b15b154..dc75dfe6187a 100644
--- a/drivers/gpu/drm/xe/xe_hw_engine.c
+++ b/drivers/gpu/drm/xe/xe_hw_engine.c
@@ -1251,3 +1251,30 @@ static int xe_hw_engine_group_suspend_lr_jobs(struct xe_hw_engine_group *group)
 
 	return 0;
 }
+
+/**
+ * xe_hw_engine_group_wait_for_dma_fence_jobs() - Wait for dma fence jobs to complete
+ * @group: The hw engine group
+ *
+ * Return: 0 on success,
+ *	   -ETIME if waiting for one job failed
+ */
+static int xe_hw_engine_group_wait_for_dma_fence_jobs(struct xe_hw_engine_group *group)
+{
+	long timeout;
+	struct xe_exec_queue *q;
+
+	lockdep_assert_held(&group->mode_sem);
+
+	list_for_each_entry(q, &group->exec_queue_list, hw_engine_group_link) {
+		if (xe_vm_in_lr_mode(q->vm))
+			continue;
+
+		timeout = dma_fence_wait(q->last_fence, false);
+
+		if (timeout < 0)
+			return -ETIME;
+	}
+
+	return 0;
+}
-- 
2.43.0