[PATCH 2/3] drm/amdgpu: Add empty HDP flush function to VCN v4.0.3

[Jane Jian]

From: Lijo Lazar <lijo.lazar at amd.com>

VCN 4.0.3 does not HDP flush with RRMT enabled. Instead, mmsch
will do the HDP flush.

This change is necessary for VCN v4.0.3, no need for backward compatibility

Signed-off-by: Lijo Lazar <lijo.lazar at amd.com>
Signed-off-by: Jane Jian <Jane.Jian at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c b/drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c
index f53054e39ebb..101b120f6fbd 100644
--- a/drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c
+++ b/drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c
@@ -1375,6 +1375,13 @@ static uint64_t vcn_v4_0_3_unified_ring_get_wptr(struct amdgpu_ring *ring)
 				    regUVD_RB_WPTR);
 }
 
+static void vcn_v4_0_3_ring_emit_hdp_flush(struct amdgpu_ring *ring)
+{
+	/* VCN engine access for HDP flush doesn't work when RRMT is enabled.
+	 * This is a workaround to avoid any HDP flush through VCN ring.
+	 */
+}
+
 /**
  * vcn_v4_0_3_unified_ring_set_wptr - set enc write pointer
  *
@@ -1415,6 +1422,7 @@ static const struct amdgpu_ring_funcs vcn_v4_0_3_unified_ring_vm_funcs = {
 	.emit_ib = vcn_v2_0_enc_ring_emit_ib,
 	.emit_fence = vcn_v2_0_enc_ring_emit_fence,
 	.emit_vm_flush = vcn_v2_0_enc_ring_emit_vm_flush,
+	.emit_hdp_flush = vcn_v4_0_3_ring_emit_hdp_flush,
 	.test_ring = amdgpu_vcn_enc_ring_test_ring,
 	.test_ib = amdgpu_vcn_unified_ring_test_ib,
 	.insert_nop = amdgpu_ring_insert_nop,
-- 
2.34.1