drm/amdgpu: add vega20 sriov capability detection

Add sriov capability detection for vega20, then can check if device is
virtual device.
Signed-off-by: Frank Min <Frank.Min@amd.com>
Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c

@@ -205,8 +205,19 @@ static const struct nbio_hdp_flush_reg nbio_v7_4_hdp_flush_reg = {
 
 static void nbio_v7_4_detect_hw_virt(struct amdgpu_device *adev)
 {
-	if (is_virtual_machine())	/* passthrough mode exclus sriov mod */
-		adev->virt.caps |= AMDGPU_PASSTHROUGH_MODE;
+	uint32_t reg;
+
+	reg = RREG32_SOC15(NBIO, 0, mmRCC_IOV_FUNC_IDENTIFIER);
+	if (reg & 1)
+		adev->virt.caps |= AMDGPU_SRIOV_CAPS_IS_VF;
+
+	if (reg & 0x80000000)
+		adev->virt.caps |= AMDGPU_SRIOV_CAPS_ENABLE_IOV;
+
+	if (!reg) {
+		if (is_virtual_machine())	/* passthrough mode exclus sriov mod */
+			adev->virt.caps |= AMDGPU_PASSTHROUGH_MODE;
+	}
 }
 
 static void nbio_v7_4_init_registers(struct amdgpu_device *adev)