From b4b3472394b147a74f86f6c6468d0a81a551c6eb Mon Sep 17 00:00:00 2001
From: Charlene Liu <Charlene.Liu@amd.com>
Date: Fri, 5 Aug 2022 12:59:47 -0400
Subject: drm/amd/display: avoid doing vm_init multiple time
Git-commit: 5544a7b5a07480192eb5fd3536462faed2c21528
Patch-mainline: v6.0-rc2
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849

[why]
this is to ensure that driver will not reprogram hvm_prefetch_req again if
it is done.

Reviewed-by: Martin Leung <Martin.Leung@amd.com>
Acked-by: Brian Chang <Brian.Chang@amd.com>
Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hubbub.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hubbub.c b/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hubbub.c
index c5e200d09038..5752271f22df 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hubbub.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hubbub.c
@@ -67,9 +67,15 @@ static uint32_t convert_and_clamp(
 void dcn21_dchvm_init(struct hubbub *hubbub)
 {
 	struct dcn20_hubbub *hubbub1 = TO_DCN20_HUBBUB(hubbub);
-	uint32_t riommu_active;
+	uint32_t riommu_active, prefetch_done;
 	int i;
 
+	REG_GET(DCHVM_RIOMMU_STAT0, HOSTVM_PREFETCH_DONE, &prefetch_done);
+
+	if (prefetch_done) {
+		hubbub->riommu_active = true;
+		return;
+	}
 	//Init DCHVM block
 	REG_UPDATE(DCHVM_CTRL0, HOSTVM_INIT_REQ, 1);
 
-- 
2.38.1