drm/amd/display: fix dcn10_hubbub_wm_read_state

The ALLOW_SR registers might not always be available.
Signed-off-by: Ken Chalmers <ken.chalmers@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hubbub.c

@@ -42,36 +42,46 @@ void hubbub1_wm_read_state(struct hubbub *hubbub,
 {
 	struct dcn_hubbub_wm_set *s;
 
+	memset(wm, 0, sizeof(struct dcn_hubbub_wm));
+
 	s = &wm->sets[0];
 	s->wm_set = 0;
 	s->data_urgent = REG_READ(DCHUBBUB_ARB_DATA_URGENCY_WATERMARK_A);
 	s->pte_meta_urgent = REG_READ(DCHUBBUB_ARB_PTE_META_URGENCY_WATERMARK_A);
+	if (REG(DCHUBBUB_ARB_ALLOW_SR_ENTER_WATERMARK_A)) {
 		s->sr_enter = REG_READ(DCHUBBUB_ARB_ALLOW_SR_ENTER_WATERMARK_A);
 		s->sr_exit = REG_READ(DCHUBBUB_ARB_ALLOW_SR_EXIT_WATERMARK_A);
+	}
 	s->dram_clk_chanage = REG_READ(DCHUBBUB_ARB_ALLOW_DRAM_CLK_CHANGE_WATERMARK_A);
 
 	s = &wm->sets[1];
 	s->wm_set = 1;
 	s->data_urgent = REG_READ(DCHUBBUB_ARB_DATA_URGENCY_WATERMARK_B);
 	s->pte_meta_urgent = REG_READ(DCHUBBUB_ARB_PTE_META_URGENCY_WATERMARK_B);
+	if (REG(DCHUBBUB_ARB_ALLOW_SR_ENTER_WATERMARK_B)) {
 		s->sr_enter = REG_READ(DCHUBBUB_ARB_ALLOW_SR_ENTER_WATERMARK_B);
 		s->sr_exit = REG_READ(DCHUBBUB_ARB_ALLOW_SR_EXIT_WATERMARK_B);
+	}
 	s->dram_clk_chanage = REG_READ(DCHUBBUB_ARB_ALLOW_DRAM_CLK_CHANGE_WATERMARK_B);
 
 	s = &wm->sets[2];
 	s->wm_set = 2;
 	s->data_urgent = REG_READ(DCHUBBUB_ARB_DATA_URGENCY_WATERMARK_C);
 	s->pte_meta_urgent = REG_READ(DCHUBBUB_ARB_PTE_META_URGENCY_WATERMARK_C);
+	if (REG(DCHUBBUB_ARB_ALLOW_SR_ENTER_WATERMARK_C)) {
 		s->sr_enter = REG_READ(DCHUBBUB_ARB_ALLOW_SR_ENTER_WATERMARK_C);
 		s->sr_exit = REG_READ(DCHUBBUB_ARB_ALLOW_SR_EXIT_WATERMARK_C);
+	}
 	s->dram_clk_chanage = REG_READ(DCHUBBUB_ARB_ALLOW_DRAM_CLK_CHANGE_WATERMARK_C);
 
 	s = &wm->sets[3];
 	s->wm_set = 3;
 	s->data_urgent = REG_READ(DCHUBBUB_ARB_DATA_URGENCY_WATERMARK_D);
 	s->pte_meta_urgent = REG_READ(DCHUBBUB_ARB_PTE_META_URGENCY_WATERMARK_D);
+	if (REG(DCHUBBUB_ARB_ALLOW_SR_ENTER_WATERMARK_D)) {
 		s->sr_enter = REG_READ(DCHUBBUB_ARB_ALLOW_SR_ENTER_WATERMARK_D);
 		s->sr_exit = REG_READ(DCHUBBUB_ARB_ALLOW_SR_EXIT_WATERMARK_D);
+	}
 	s->dram_clk_chanage = REG_READ(DCHUBBUB_ARB_ALLOW_DRAM_CLK_CHANGE_WATERMARK_D);
 }