[RFC v1 4/9] drm/xe/hw_engine_group: Add helper to suspend LR jobs

[Francois Dugast]

This is a required feature for dma fence jobs to preempt long running
jobs in order to ensure mutual exclusion on a given hw engine group.

Signed-off-by: Francois Dugast <francois.dugast at intel.com>
---
 drivers/gpu/drm/xe/xe_hw_engine.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_hw_engine.c b/drivers/gpu/drm/xe/xe_hw_engine.c
index 4dcc885a55c8..850f7b15b154 100644
--- a/drivers/gpu/drm/xe/xe_hw_engine.c
+++ b/drivers/gpu/drm/xe/xe_hw_engine.c
@@ -1223,3 +1223,31 @@ int xe_hw_engine_group_del_exec_queue(struct xe_hw_engine_group *group, struct x
 
 	return 0;
 }
+
+/**
+ * xe_hw_engine_group_suspend_lr_jobs() - Suspend the long running jobs of this hw engine group
+ * @group: The hw engine group
+ *
+ * Return: 0 on success,
+ *	   -EINVAL if one jobs could not be suspended
+ */
+static int xe_hw_engine_group_suspend_lr_jobs(struct xe_hw_engine_group *group)
+{
+	int err;
+	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;
+
+		err = q->ops->suspend(q);
+		if (err)
+			return err;
+
+		q->ops->suspend_wait(q);
+	}
+
+	return 0;
+}
-- 
2.43.0