[PATCH 2/2] drm/xe: Do not use CT lock in TLB code

[Stuart Summers]

From: Nirmoy Das <nirmoy.das at intel.com>

Stop abusing CT lock for GT TLB invalidation fence seqno, add a
dedicated lock.

Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
---
 drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c | 17 ++++++++++-------
 drivers/gpu/drm/xe/xe_gt_types.h            | 13 ++++++++++---
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
index 031c4d43f36b..c2bb53362d74 100644
--- a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
+++ b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
@@ -3,6 +3,8 @@
  * Copyright © 2023 Intel Corporation
  */
 
+#include <drm/drm_managed.h>
+
 #include "xe_gt_tlb_invalidation.h"
 
 #include "abi/guc_actions_abi.h"
@@ -123,7 +125,8 @@ int xe_gt_tlb_invalidation_init_early(struct xe_gt *gt)
 	INIT_DELAYED_WORK(&gt->tlb_invalidation.fence_tdr,
 			  xe_gt_tlb_fence_timeout);
 
-	return 0;
+	return drmm_mutex_init(&gt_to_xe(gt)->drm,
+			       &gt->tlb_invalidation.seqno_lock);
 }
 
 /**
@@ -142,7 +145,7 @@ void xe_gt_tlb_invalidation_reset(struct xe_gt *gt)
 	 * appear.
 	 */
 
-	mutex_lock(&gt->uc.guc.ct.lock);
+	mutex_lock(&gt->tlb_invalidation.seqno_lock);
 	spin_lock_irq(&gt->tlb_invalidation.pending_lock);
 	cancel_delayed_work(&gt->tlb_invalidation.fence_tdr);
 	/*
@@ -162,7 +165,7 @@ void xe_gt_tlb_invalidation_reset(struct xe_gt *gt)
 				 &gt->tlb_invalidation.pending_fences, link)
 		invalidation_fence_signal(gt_to_xe(gt), fence);
 	spin_unlock_irq(&gt->tlb_invalidation.pending_lock);
-	mutex_unlock(&gt->uc.guc.ct.lock);
+	mutex_unlock(&gt->tlb_invalidation.seqno_lock);
 }
 
 static bool tlb_invalidation_seqno_past(struct xe_gt *gt, int seqno)
@@ -195,13 +198,13 @@ static int send_tlb_invalidation(struct xe_guc *guc,
 	 * need to be updated.
 	 */
 
-	mutex_lock(&guc->ct.lock);
+	mutex_lock(&gt->tlb_invalidation.seqno_lock);
 	seqno = gt->tlb_invalidation.seqno;
 	fence->seqno = seqno;
 	trace_xe_gt_tlb_invalidation_fence_send(xe, fence);
 	action[1] = seqno;
-	ret = xe_guc_ct_send_locked(&guc->ct, action, len,
-				    G2H_LEN_DW_TLB_INVALIDATE, 1);
+	ret = xe_guc_ct_send(&guc->ct, action, len,
+			     G2H_LEN_DW_TLB_INVALIDATE, 1);
 	if (!ret) {
 		spin_lock_irq(&gt->tlb_invalidation.pending_lock);
 		/*
@@ -232,7 +235,7 @@ static int send_tlb_invalidation(struct xe_guc *guc,
 		if (!gt->tlb_invalidation.seqno)
 			gt->tlb_invalidation.seqno = 1;
 	}
-	mutex_unlock(&guc->ct.lock);
+	mutex_unlock(&gt->tlb_invalidation.seqno_lock);
 	xe_gt_stats_incr(gt, XE_GT_STATS_ID_TLB_INVAL, 1);
 
 	return ret;
diff --git a/drivers/gpu/drm/xe/xe_gt_types.h b/drivers/gpu/drm/xe/xe_gt_types.h
index be81687cbe2b..4736a608a881 100644
--- a/drivers/gpu/drm/xe/xe_gt_types.h
+++ b/drivers/gpu/drm/xe/xe_gt_types.h
@@ -187,17 +187,24 @@ struct xe_gt {
 
 	/** @tlb_invalidation: TLB invalidation state */
 	struct {
-		/** @tlb_invalidation.seqno: TLB invalidation seqno, protected by CT lock */
+		/** @tlb_invalidation.seqno_lock: TLB invalidation seqno lock */
+		struct mutex seqno_lock;
+		/**
+		 * @tlb_invalidation.seqno: TLB invalidation seqno, protected
+		 * by @tlb_invalidation.seqno_lock
+		 */
 #define TLB_INVALIDATION_SEQNO_MAX	0x100000
 		int seqno;
 		/**
 		 * @tlb_invalidation.seqno_recv: last received TLB invalidation seqno,
-		 * protected by CT lock
+		 * protected by @tlb_invalidation.seqno_lock (send) and
+		 * @tlb_invalidation.pending_lock (send, recv)
 		 */
 		int seqno_recv;
 		/**
 		 * @tlb_invalidation.pending_fences: list of pending fences waiting TLB
-		 * invaliations, protected by CT lock
+		 * invaliations, protected by @tlb_invalidation.seqno_lock
+		 * (send) and @tlb_invalidation.pending_lock (send, recv)
 		 */
 		struct list_head pending_fences;
 		/**
-- 
2.34.1