[PATCH v2 2/2] drm/amdgpu: Don't flush HDP on A+A

[Eric Huang]

With XGMI connection flushing HDP on PCIe is unnecessary,
it is also to optimize memory allocation latency.

Signed-off-by: Eric Huang <jinhuieric.huang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_hdp.h | 1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c  | 3 ++-
 drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c   | 1 +
 drivers/gpu/drm/amd/amdgpu/hdp_v4_0.c   | 3 +++
 4 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hdp.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_hdp.h
index 7ec99d591584..1ca23f2f51d2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hdp.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hdp.h
@@ -44,6 +44,7 @@ struct amdgpu_hdp {
 	struct ras_common_if			*ras_if;
 	const struct amdgpu_hdp_funcs		*funcs;
 	const struct amdgpu_hdp_ras_funcs	*ras_funcs;
+	bool	no_flush;
 };
 
 int amdgpu_hdp_ras_late_init(struct amdgpu_device *adev);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
index aaa2574ce9bc..f31eae2931f3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
@@ -226,7 +226,8 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
 	if (!(adev->flags & AMD_IS_APU))
 #endif
 	{
-		if (ring->funcs->emit_hdp_flush)
+		if (ring->funcs->emit_hdp_flush &&
+			!adev->hdp.no_flush)
 			amdgpu_ring_emit_hdp_flush(ring);
 		else
 			amdgpu_asic_flush_hdp(adev, ring);
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
index 2749621d5f63..6e1eab615914 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -1223,6 +1223,7 @@ static int gmc_v9_0_early_init(void *handle)
 		adev->gmc.xgmi.supported = true;
 		adev->gmc.xgmi.connected_to_cpu =
 			adev->smuio.funcs->is_host_gpu_xgmi_supported(adev);
+		adev->hdp.no_flush = adev->gmc.xgmi.connected_to_cpu;
 	}
 
 	gmc_v9_0_set_gmc_funcs(adev);
diff --git a/drivers/gpu/drm/amd/amdgpu/hdp_v4_0.c b/drivers/gpu/drm/amd/amdgpu/hdp_v4_0.c
index 74b90cc2bf48..e1b2face8656 100644
--- a/drivers/gpu/drm/amd/amdgpu/hdp_v4_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/hdp_v4_0.c
@@ -40,6 +40,9 @@
 static void hdp_v4_0_flush_hdp(struct amdgpu_device *adev,
 				struct amdgpu_ring *ring)
 {
+	if (adev->hdp.no_flush)
+		return;
+
 	if (!ring || !ring->funcs->emit_wreg)
 		WREG32_NO_KIQ((adev->rmmio_remap.reg_offset + KFD_MMIO_REMAP_HDP_MEM_FLUSH_CNTL) >> 2, 0);
 	else
-- 
2.25.1