drm/amd/display: fix hotplug during display off

[why]
HPD is not suppressed when we lower
clocks on renoir. B/c of this we do link
training when the 48mhz refclk is off, which
will cause ASIC hang.

[how]
Exit optimized power state for detection purpose.
Signed-off-by: Joseph Gravenor <joseph.gravenor@amd.com>
Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c

@@ -52,6 +52,44 @@
 #define REG(reg_name) \
 	(CLK_BASE.instance[0].segment[mm ## reg_name ## _BASE_IDX] + mm ## reg_name)
 
+
+/* TODO: evaluate how to lower or disable all dcn clocks in screen off case */
+int rn_get_active_display_cnt_wa(
+		struct dc *dc,
+		struct dc_state *context)
+{
+	int i, display_count;
+	bool hdmi_present = false;
+
+	display_count = 0;
+	for (i = 0; i < context->stream_count; i++) {
+		const struct dc_stream_state *stream = context->streams[i];
+
+		if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
+			hdmi_present = true;
+	}
+
+	for (i = 0; i < dc->link_count; i++) {
+		const struct dc_link *link = dc->links[i];
+
+		/*
+		 * Only notify active stream or virtual stream.
+		 * Need to notify virtual stream to work around
+		 * headless case. HPD does not fire when system is in
+		 * S0i2.
+		 */
+		/* abusing the fact that the dig and phy are coupled to see if the phy is enabled */
+		if (link->link_enc->funcs->is_dig_enabled(link->link_enc))
+			display_count++;
+	}
+
+	/* WA for hang on HDMI after display off back back on*/
+	if (display_count == 0 && hdmi_present)
+		display_count = 1;
+
+	return display_count;
+}
+
 void rn_update_clocks(struct clk_mgr *clk_mgr_base,
 			struct dc_state *context,
 			bool safe_to_lower)
@@ -62,17 +100,36 @@ void rn_update_clocks(struct clk_mgr *clk_mgr_base,
 	int display_count;
 	bool update_dppclk = false;
 	bool update_dispclk = false;
-	bool enter_display_off = false;
 	bool dpp_clock_lowered = false;
-	struct dmcu *dmcu = clk_mgr_base->ctx->dc->res_pool->dmcu;
 
-	display_count = clk_mgr_helper_get_active_display_cnt(dc, context);
+	struct dmcu *dmcu = clk_mgr_base->ctx->dc->res_pool->dmcu;
 
-	if (display_count == 0)
-		enter_display_off = true;
+	if (dc->work_arounds.skip_clock_update)
+		return;
 
-	if (enter_display_off == safe_to_lower) {
-		rn_vbios_smu_set_display_count(clk_mgr, display_count);
+	/*
+	 * if it is safe to lower, but we are already in the lower state, we don't have to do anything
+	 * also if safe to lower is false, we just go in the higher state
+	 */
+	if (safe_to_lower) {
+		/* check that we're not already in lower */
+		if (clk_mgr_base->clks.pwr_state != DCN_PWR_STATE_OPTIMIZED) {
+
+			display_count = rn_get_active_display_cnt_wa(dc, context);
+			/* if we can go lower, go lower */
+			if (display_count == 0) {
+				rn_vbios_smu_set_dcn_low_power_state(clk_mgr, DCN_PWR_STATE_OPTIMIZED);
+				/* update power state */
+				clk_mgr_base->clks.pwr_state = DCN_PWR_STATE_OPTIMIZED;
+			}
+		}
+	} else {
+		/* check that we're not already in the normal state */
+		if (clk_mgr_base->clks.pwr_state != DCN_PWR_STATE_NORMAL) {
+			rn_vbios_smu_set_dcn_low_power_state(clk_mgr, DCN_PWR_STATE_NORMAL);
+			/* update power state */
+			clk_mgr_base->clks.pwr_state = DCN_PWR_STATE_NORMAL;
+		}
 	}
 
 	if (should_set_clock(safe_to_lower, new_clocks->phyclk_khz, clk_mgr_base->clks.phyclk_khz)) {
@@ -329,10 +386,19 @@ void rn_enable_pme_wa(struct clk_mgr *clk_mgr_base)
 	rn_vbios_smu_enable_pme_wa(clk_mgr);
 }
 
+void rn_init_clocks(struct clk_mgr *clk_mgr)
+{
+	memset(&(clk_mgr->clks), 0, sizeof(struct dc_clocks));
+	// Assumption is that boot state always supports pstate
+	clk_mgr->clks.p_state_change_support = true;
+	clk_mgr->clks.prev_p_state_change_support = true;
+	clk_mgr->clks.pwr_state = DCN_PWR_STATE_NORMAL;
+}
+
 static struct clk_mgr_funcs dcn21_funcs = {
 	.get_dp_ref_clk_frequency = dce12_get_dp_ref_freq_khz,
 	.update_clocks = rn_update_clocks,
-	.init_clocks = dcn2_init_clocks,
+	.init_clocks = rn_init_clocks,
 	.enable_pme_wa = rn_enable_pme_wa,
 	/* .dump_clk_registers = rn_dump_clk_registers */
 };

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.h

@@ -30,7 +30,6 @@ struct rn_clk_registers {
 	uint32_t CLK1_CLK0_CURRENT_CNT; /* DPREFCLK */
 };
 
-
 void rn_clk_mgr_construct(struct dc_context *ctx,
 		struct clk_mgr_internal *clk_mgr,
 		struct pp_smu_funcs *pp_smu,

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr_vbios_smu.c

@@ -175,12 +175,19 @@ int rn_vbios_smu_set_dppclk(struct clk_mgr_internal *clk_mgr, int requested_dpp_
 	return actual_dppclk_set_mhz * 1000;
 }
 
-void rn_vbios_smu_set_display_count(struct clk_mgr_internal *clk_mgr, int display_count)
+void rn_vbios_smu_set_dcn_low_power_state(struct clk_mgr_internal *clk_mgr, enum dcn_pwr_state state)
 {
+	int disp_count;
+
+	if (state == DCN_PWR_STATE_OPTIMIZED)
+		disp_count = 0;
+	else
+		disp_count = 1;
+
 	rn_vbios_smu_send_msg_with_param(
-			clk_mgr,
-			VBIOSSMC_MSG_SetDisplayCount,
-			display_count);
+		clk_mgr,
+		VBIOSSMC_MSG_SetDisplayCount,
+		disp_count);
 }
 
 void rn_vbios_smu_enable_48mhz_tmdp_refclk_pwrdwn(struct clk_mgr_internal *clk_mgr)

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr_vbios_smu.h

@@ -33,7 +33,7 @@ int rn_vbios_smu_set_hard_min_dcfclk(struct clk_mgr_internal *clk_mgr, int reque
 int rn_vbios_smu_set_min_deep_sleep_dcfclk(struct clk_mgr_internal *clk_mgr, int requested_min_ds_dcfclk_khz);
 void rn_vbios_smu_set_phyclk(struct clk_mgr_internal *clk_mgr, int requested_phyclk_khz);
 int rn_vbios_smu_set_dppclk(struct clk_mgr_internal *clk_mgr, int requested_dpp_khz);
-void rn_vbios_smu_set_display_count(struct clk_mgr_internal *clk_mgr, int display_count);
+void rn_vbios_smu_set_dcn_low_power_state(struct clk_mgr_internal *clk_mgr, int display_count);
 void rn_vbios_smu_enable_48mhz_tmdp_refclk_pwrdwn(struct clk_mgr_internal *clk_mgr);
 void rn_vbios_smu_enable_pme_wa(struct clk_mgr_internal *clk_mgr);
 

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -743,7 +743,7 @@ static bool wait_for_alt_mode(struct dc_link *link)
  * This does not create remote sinks but will trigger DM
  * to start MST detection if a branch is detected.
  */
-bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
+bool dc_link_detect_helper(struct dc_link *link, enum dc_detect_reason reason)
 {
 	struct dc_sink_init_data sink_init_data = { 0 };
 	struct display_sink_capability sink_caps = { 0 };
@@ -759,6 +759,7 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 	bool same_dpcd = true;
 	enum dc_connection_type new_connection_type = dc_connection_none;
 	bool perform_dp_seamless_boot = false;
+
 	DC_LOGGER_INIT(link->ctx->logger);
 
 	if (dc_is_virtual_signal(link->connector_signal))
@@ -1065,6 +1066,24 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 		dc_sink_release(prev_sink);
 
 	return true;
+
+}
+
+bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
+{
+	const struct dc *dc = link->dc;
+	bool ret;
+	/* get out of low power state */
+
+	if (dc->hwss.exit_optimized_pwr_state)
+		dc->hwss.exit_optimized_pwr_state(dc, dc->current_state);
+
+	ret = dc_link_detect_helper(link, reason);
+
+	if (dc->hwss.optimize_pwr_state)
+		dc->hwss.optimize_pwr_state(dc, dc->current_state);
+
+	return ret;
 }
 
 bool dc_link_get_hpd_state(struct dc_link *dc_link)

drivers/gpu/drm/amd/display/dc/dc.h

@@ -246,6 +246,11 @@ enum wm_report_mode {
 	WM_REPORT_OVERRIDE = 1,
 };
 
+enum dcn_pwr_state {
+	DCN_PWR_STATE_OPTIMIZED = 0,
+	DCN_PWR_STATE_NORMAL = 1
+};
+
 /*
  * For any clocks that may differ per pipe
  * only the max is stored in this structure
@@ -260,7 +265,7 @@ struct dc_clocks {
 	int phyclk_khz;
 	int dramclk_khz;
 	bool p_state_change_support;
-
+	enum dcn_pwr_state pwr_state;
 	/*
 	 * Elements below are not compared for the purposes of
 	 * optimization required

drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h

@@ -232,6 +232,13 @@ struct hw_sequencer_funcs {
 			struct dc *dc,
 			struct dc_state *context);
 
+	void (*exit_optimized_pwr_state)(
+			const struct dc *dc,
+			struct dc_state *context);
+	void (*optimize_pwr_state)(
+			const struct dc *dc,
+			struct dc_state *context);
+
 #if defined(CONFIG_DRM_AMD_DC_DCN2_0)
 	bool (*update_bandwidth)(
 			struct dc *dc,