[PATCH v4 23/28] drm/xe/pf: Add wait helper for VF FLR

["Michał Winiarski" <michal.winiarski@intel.com>]

VF FLR requires additional processing done by PF driver.
The processing is done after FLR is already finished from PCIe
perspective.
In order to avoid a scenario where migration state transitions while
PF processing is still in progress, additional synchronization
point is needed.
Add a helper that will be used as part of VF driver struct
pci_error_handlers .reset_done() callback.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
---
 drivers/gpu/drm/xe/xe_sriov_pf_control.c | 24 ++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_sriov_pf_control.h |  1 +
 2 files changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_control.c b/drivers/gpu/drm/xe/xe_sriov_pf_control.c
index eec218c710278..acaf38026c763 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_control.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_control.c
@@ -123,6 +123,30 @@ int xe_sriov_pf_control_reset_vf(struct xe_device *xe, unsigned int vfid)
 	return result;
 }
 
+/**
+ * xe_sriov_pf_control_wait_flr() - Wait for a VF reset (FLR) to complete.
+ * @xe: the &xe_device
+ * @vfid: the VF identifier
+ *
+ * This function is for PF only.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_sriov_pf_control_wait_flr(struct xe_device *xe, unsigned int vfid)
+{
+	struct xe_gt *gt;
+	unsigned int id;
+	int result = 0;
+	int err;
+
+	for_each_gt(gt, xe, id) {
+		err = xe_gt_sriov_pf_control_wait_flr(gt, vfid);
+		result = result ? -EUCLEAN : err;
+	}
+
+	return result;
+}
+
 /**
  * xe_sriov_pf_control_sync_flr() - Synchronize a VF FLR between all GTs.
  * @xe: the &xe_device
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_control.h b/drivers/gpu/drm/xe/xe_sriov_pf_control.h
index 30318c1fba34e..ef9f219b21096 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_control.h
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_control.h
@@ -12,6 +12,7 @@ int xe_sriov_pf_control_pause_vf(struct xe_device *xe, unsigned int vfid);
 int xe_sriov_pf_control_resume_vf(struct xe_device *xe, unsigned int vfid);
 int xe_sriov_pf_control_stop_vf(struct xe_device *xe, unsigned int vfid);
 int xe_sriov_pf_control_reset_vf(struct xe_device *xe, unsigned int vfid);
+int xe_sriov_pf_control_wait_flr(struct xe_device *xe, unsigned int vfid);
 int xe_sriov_pf_control_sync_flr(struct xe_device *xe, unsigned int vfid);
 int xe_sriov_pf_control_trigger_save_vf(struct xe_device *xe, unsigned int vfid);
 int xe_sriov_pf_control_finish_save_vf(struct xe_device *xe, unsigned int vfid);
-- 
2.51.2