drm/amd/display: Fix Null point error if smu ip was disabled

from AI, SMU Ip is not indispensable to driver and can be
disabled by user via module parameter ip_block_mask.
so the pp_handle may be NULL.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_pp_smu.c

@@ -101,7 +101,7 @@ bool dm_pp_apply_display_requirements(
 			adev->pm.pm_display_cfg.displays[i].controller_id = dc_cfg->pipe_idx + 1;
 		}
 
-		if (adev->powerplay.pp_funcs->display_configuration_change)
+		if (adev->powerplay.pp_funcs && adev->powerplay.pp_funcs->display_configuration_change)
 			adev->powerplay.pp_funcs->display_configuration_change(
 				adev->powerplay.pp_handle,
 				&adev->pm.pm_display_cfg);
@@ -304,7 +304,7 @@ bool dm_pp_get_clock_levels_by_type(
 	struct amd_pp_simple_clock_info validation_clks = { 0 };
 	uint32_t i;
 
-	if (adev->powerplay.pp_funcs->get_clock_by_type) {
+	if (adev->powerplay.pp_funcs && adev->powerplay.pp_funcs->get_clock_by_type) {
 		if (adev->powerplay.pp_funcs->get_clock_by_type(pp_handle,
 			dc_to_pp_clock_type(clk_type), &pp_clks)) {
 		/* Error in pplib. Provide default values. */
@@ -315,7 +315,7 @@ bool dm_pp_get_clock_levels_by_type(
 
 	pp_to_dc_clock_levels(&pp_clks, dc_clks, clk_type);
 
-	if (adev->powerplay.pp_funcs->get_display_mode_validation_clocks) {
+	if (adev->powerplay.pp_funcs && adev->powerplay.pp_funcs->get_display_mode_validation_clocks) {
 		if (adev->powerplay.pp_funcs->get_display_mode_validation_clocks(
 						pp_handle, &validation_clks)) {
 			/* Error in pplib. Provide default values. */
@@ -398,6 +398,9 @@ bool dm_pp_get_clock_levels_by_type_with_voltage(
 	struct pp_clock_levels_with_voltage pp_clk_info = {0};
 	const struct amd_pm_funcs *pp_funcs = adev->powerplay.pp_funcs;
 
+	if (!pp_funcs || !pp_funcs->get_clock_by_type_with_voltage)
+		return false;
+
 	if (pp_funcs->get_clock_by_type_with_voltage(pp_handle,
 						     dc_to_pp_clock_type(clk_type),
 						     &pp_clk_info))
@@ -438,7 +441,7 @@ bool dm_pp_apply_clock_for_voltage_request(
 	if (!pp_clock_request.clock_type)
 		return false;
 
-	if (adev->powerplay.pp_funcs->display_clock_voltage_request)
+	if (adev->powerplay.pp_funcs && adev->powerplay.pp_funcs->display_clock_voltage_request)
 		ret = adev->powerplay.pp_funcs->display_clock_voltage_request(
 			adev->powerplay.pp_handle,
 			&pp_clock_request);
@@ -455,7 +458,7 @@ bool dm_pp_get_static_clocks(
 	struct amd_pp_clock_info pp_clk_info = {0};
 	int ret = 0;
 
-	if (adev->powerplay.pp_funcs->get_current_clocks)
+	if (adev->powerplay.pp_funcs && adev->powerplay.pp_funcs->get_current_clocks)
 		ret = adev->powerplay.pp_funcs->get_current_clocks(
 			adev->powerplay.pp_handle,
 			&pp_clk_info);
@@ -505,6 +508,9 @@ void pp_rv_set_wm_ranges(struct pp_smu *pp,
 	wm_with_clock_ranges.num_wm_dmif_sets = ranges->num_reader_wm_sets;
 	wm_with_clock_ranges.num_wm_mcif_sets = ranges->num_writer_wm_sets;
 
+	if (!pp_funcs || !pp_funcs->set_watermarks_for_clocks_ranges)
+		return;
+
 	for (i = 0; i < wm_with_clock_ranges.num_wm_dmif_sets; i++) {
 		if (ranges->reader_wm_sets[i].wm_inst > 3)
 			wm_dce_clocks[i].wm_set_id = WM_SET_A;