[PATCH v1] drm/xe/uapi: Bring back reset uevent

[Raag Jadav]

From: Lucas De Marchi <lucas.demarchi at intel.com>

Bring back uevent for gt reset failure with better uapi naming.
With this in place we can receive failure event using udev.

$ udevadm monitor --property --kernel
monitor will print the received events for:
KERNEL - the kernel uevent

KERNEL[871.188570] change   /devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:01.0/0000:03:00.0 (pci)
ACTION=change
DEVPATH=/devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:01.0/0000:03:00.0
SUBSYSTEM=pci
DEVICE_STATUS=NEEDS_RESET
REASON=GT_RESET_FAILED
TILE_ID=0
GT_ID=0
DRIVER=xe
PCI_CLASS=30000
PCI_ID=8086:56B1
PCI_SUBSYS_ID=8086:1210
PCI_SLOT_NAME=0000:03:00.0
MODALIAS=pci:v00008086d000056B1sv00008086sd00001210bc03sc00i00
SEQNUM=6104

Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
Signed-off-by: Raag Jadav <raag.jadav at intel.com>
---
 drivers/gpu/drm/xe/xe_gt.c | 27 +++++++++++++++++++++++++--
 include/uapi/drm/xe_drm.h  | 17 +++++++++++++++++
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
index b04e47186f5b..5ceef0059861 100644
--- a/drivers/gpu/drm/xe/xe_gt.c
+++ b/drivers/gpu/drm/xe/xe_gt.c
@@ -740,6 +740,30 @@ static int do_gt_restart(struct xe_gt *gt)
 	return 0;
 }
 
+static void xe_uevent_gt_reset_failure(struct pci_dev *pdev, u8 tile_id, u8 gt_id)
+{
+	char *reset_event[5];
+
+	reset_event[0] = DRM_XE_RESET_REQUIRED_UEVENT;
+	reset_event[1] = DRM_XE_RESET_REQUIRED_UEVENT_REASON_GT;
+	reset_event[2] = kasprintf(GFP_KERNEL, "TILE_ID=%d", tile_id);
+	reset_event[3] = kasprintf(GFP_KERNEL, "GT_ID=%d", gt_id);
+	reset_event[4] = NULL;
+	kobject_uevent_env(&pdev->dev.kobj, KOBJ_CHANGE, reset_event);
+
+	kfree(reset_event[2]);
+	kfree(reset_event[3]);
+}
+
+static void gt_reset_failed(struct xe_gt *gt, int err)
+{
+	xe_gt_err(gt, "reset failed (%pe)\n", ERR_PTR(err));
+
+	/* Notify userspace about gt reset failure */
+	xe_uevent_gt_reset_failure(to_pci_dev(gt_to_xe(gt)->drm.dev),
+				   gt_to_tile(gt)->id, gt->info.id);
+}
+
 static int gt_reset(struct xe_gt *gt)
 {
 	int err;
@@ -795,8 +819,7 @@ static int gt_reset(struct xe_gt *gt)
 	XE_WARN_ON(xe_uc_start(&gt->uc));
 	xe_pm_runtime_put(gt_to_xe(gt));
 err_fail:
-	xe_gt_err(gt, "reset failed (%pe)\n", ERR_PTR(err));
-
+	gt_reset_failed(gt, err);
 	xe_device_declare_wedged(gt_to_xe(gt));
 
 	return err;
diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
index 19619d4952a8..9ea3be97535e 100644
--- a/include/uapi/drm/xe_drm.h
+++ b/include/uapi/drm/xe_drm.h
@@ -20,6 +20,7 @@ extern "C" {
  *   2. Extension definition and helper structs
  *   3. IOCTL's Query structs in the order of the Query's entries.
  *   4. The rest of IOCTL structs in the order of IOCTL declaration.
+ *   5. uEvents
  */
 
 /**
@@ -1686,6 +1687,22 @@ struct drm_xe_oa_stream_info {
 	__u64 reserved[3];
 };
 
+/**
+ * DOC: uevent generated by xe on it's pci node.
+ *
+ * DRM_XE_RESET_REQUIRED_UEVENT - Event is generated when device needs reset.
+ * The REASON is provided along with the event for which reset is required.
+ * On the basis of REASONS, additional information might be supplied.
+ */
+#define DRM_XE_RESET_REQUIRED_UEVENT "DEVICE_STATUS=NEEDS_RESET"
+
+/**
+ * DRM_XE_RESET_REQUIRED_UEVENT_REASON_GT - Reason provided to DRM_XE_RESET_REQUIRED_UEVENT
+ * incase of gt reset failure. The additional information supplied is tile id and
+ * gt id of the gt unit for which reset has failed.
+ */
+#define DRM_XE_RESET_REQUIRED_UEVENT_REASON_GT "REASON=GT_RESET_FAILED"
+
 #if defined(__cplusplus)
 }
 #endif
-- 
2.34.1