drm/msm/dp: handle irq_hpd with sink_count = 0 correctly

irq_hpd interrupt should be handled after dongle plugged in and
before dongle unplugged. Hence irq_hpd interrupt is enabled at
the end of the plugin handle and disabled at the beginning of
unplugged handle. Current irq_hpd with sink_count = 0 is wrongly
handled same as the dongle unplugged which tears down the mainlink
and disables the phy. This patch fixes this problem by only tearing
down the mainlink but keeping phy enabled at irq_hpd with
sink_count = 0 handle so that next irq_hpd with sink_count =1 can be
handled by setup mainlink only. This patch also set dongle into D3
(power off) state at end of handling irq_hpd with sink_count = 0.

Changes in v2:
-- add ctrl->phy_Power_count

Changes in v3:
-- del ctrl->phy_Power_count
-- add phy_power_off to dp_ctrl_off_link_stream()

Changes in v4:
-- return immediately if clock disable failed at dp_ctrl_off_link_stream()

Changes in v5:
-- set dongle to D3 (power off) state at dp_ctrl_off_link_stream()

Changes in v6:
-- add Fixes tag

Fixes: ea9f337ce81e ("drm/msm/dp: reset dp controller only at boot up and pm_resume")
Signed-off-by: Kuogee Hsieh <[e-mail]>
Tested-by: Stephen Boyd <[e-mail]>
Reviewed-by: Stephen Boyd <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Clark <[e-mail]>

drivers/gpu/drm/msm/dp/dp_catalog.c

···
 
 	u32 reftimer = dp_read_aux(catalog, REG_DP_DP_HPD_REFTIMER);
 
-	/* enable HPD interrupts */
+	/* enable HPD plug and unplug interrupts */
 	dp_catalog_hpd_config_intr(dp_catalog,
-		DP_DP_HPD_PLUG_INT_MASK | DP_DP_IRQ_HPD_INT_MASK
-		| DP_DP_HPD_UNPLUG_INT_MASK | DP_DP_HPD_REPLUG_INT_MASK, true);
+		DP_DP_HPD_PLUG_INT_MASK | DP_DP_HPD_UNPLUG_INT_MASK, true);
 
 	/* Configure REFTIMER and enable it */
 	reftimer |= DP_DP_HPD_REFTIMER_ENABLE;

drivers/gpu/drm/msm/dp/dp_ctrl.c

···
 	return ret;
 }
 
+int dp_ctrl_off_link_stream(struct dp_ctrl *dp_ctrl)
+{
+	struct dp_ctrl_private *ctrl;
+	struct dp_io *dp_io;
+	struct phy *phy;
+	int ret;
+
+	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
+	dp_io = &ctrl->parser->io;
+	phy = dp_io->phy;
+
+	/* set dongle to D3 (power off) mode */
+	dp_link_psm_config(ctrl->link, &ctrl->panel->link_info, true);
+
+	dp_catalog_ctrl_mainlink_ctrl(ctrl->catalog, false);
+
+	ret = dp_power_clk_enable(ctrl->power, DP_STREAM_PM, false);
+	if (ret) {
+		DRM_ERROR("Failed to disable pixel clocks. ret=%d\n", ret);
+		return ret;
+	}
+
+	ret = dp_power_clk_enable(ctrl->power, DP_CTRL_PM, false);
+	if (ret) {
+		DRM_ERROR("Failed to disable link clocks. ret=%d\n", ret);
+		return ret;
+	}
+
+	phy_power_off(phy);
+
+	/* aux channel down, reinit phy */
+	phy_exit(phy);
+	phy_init(phy);
+
+	DRM_DEBUG_DP("DP off link/stream done\n");
+	return ret;
+}
+
+void dp_ctrl_off_phy(struct dp_ctrl *dp_ctrl)
+{
+	struct dp_ctrl_private *ctrl;
+	struct dp_io *dp_io;
+	struct phy *phy;
+
+	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
+	dp_io = &ctrl->parser->io;
+	phy = dp_io->phy;
+
+	dp_catalog_ctrl_reset(ctrl->catalog);
+
+	phy_exit(phy);
+
+	DRM_DEBUG_DP("DP off phy done\n");
+}
+
 int dp_ctrl_off(struct dp_ctrl *dp_ctrl)
 {
 	struct dp_ctrl_private *ctrl;

drivers/gpu/drm/msm/dp/dp_ctrl.h

···
 void dp_ctrl_host_deinit(struct dp_ctrl *dp_ctrl);
 int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl);
 int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl);
+int dp_ctrl_off_link_stream(struct dp_ctrl *dp_ctrl);
+void dp_ctrl_off_phy(struct dp_ctrl *dp_ctrl);
 int dp_ctrl_off(struct dp_ctrl *dp_ctrl);
 void dp_ctrl_push_idle(struct dp_ctrl *dp_ctrl);
 void dp_ctrl_isr(struct dp_ctrl *dp_ctrl);

drivers/gpu/drm/msm/dp/dp_display.c

···
 	dp->dp_display.max_pclk_khz = DP_MAX_PIXEL_CLK_KHZ;
 	dp->dp_display.max_dp_lanes = dp->parser->max_dp_lanes;
 
+	/*
+	 * set sink to normal operation mode -- D0
+	 * before dpcd read
+	 */
+	dp_link_psm_config(dp->link, &dp->panel->link_info, false);
+
 	dp_link_reset_phy_params_vx_px(dp->link);
 	rc = dp_ctrl_on_link(dp->ctrl);
 	if (rc) {
···
 
 	dp_display_host_init(dp, false);
 
-	/*
-	 * set sink to normal operation mode -- D0
-	 * before dpcd read
-	 */
-	dp_link_psm_config(dp->link, &dp->panel->link_info, false);
 	rc = dp_display_process_hpd_high(dp);
 end:
 	return rc;
···
 		dp_add_event(dp, EV_CONNECT_PENDING_TIMEOUT, 0, tout);
 	}
 
+	/* enable HDP irq_hpd/replug interrupt */
+	dp_catalog_hpd_config_intr(dp->catalog,
+		DP_DP_IRQ_HPD_INT_MASK | DP_DP_HPD_REPLUG_INT_MASK, true);
+
 	mutex_unlock(&dp->event_mutex);
 
 	/* uevent will complete connection part */
···
 	mutex_lock(&dp->event_mutex);
 
 	state = dp->hpd_state;
-	if (state == ST_DISCONNECT_PENDING || state == ST_DISCONNECTED) {
+
+	/* disable irq_hpd/replug interrupts */
+	dp_catalog_hpd_config_intr(dp->catalog,
+		DP_DP_IRQ_HPD_INT_MASK | DP_DP_HPD_REPLUG_INT_MASK, false);
+
+	/* unplugged, no more irq_hpd handle */
+	dp_del_event(dp, EV_IRQ_HPD_INT);
+
+	if (state == ST_DISCONNECTED) {
+		/* triggered by irq_hdp with sink_count = 0 */
+		if (dp->link->sink_count == 0) {
+			dp_ctrl_off_phy(dp->ctrl);
+			hpd->hpd_high = 0;
+			dp->core_initialized = false;
+		}
+		mutex_unlock(&dp->event_mutex);
+		return 0;
+	}
+
+	if (state == ST_DISCONNECT_PENDING) {
 		mutex_unlock(&dp->event_mutex);
 		return 0;
 	}
···
 
 	dp->hpd_state = ST_DISCONNECT_PENDING;
 
-	/* disable HPD plug interrupt until disconnect is done */
-	dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_PLUG_INT_MASK
-				| DP_DP_IRQ_HPD_INT_MASK, false);
+	/* disable HPD plug interrupts */
+	dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_PLUG_INT_MASK, false);
 
 	hpd->hpd_high = 0;
 
···
 	/* signal the disconnect event early to ensure proper teardown */
 	dp_display_handle_plugged_change(g_dp_display, false);
 
-	dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_PLUG_INT_MASK |
-					DP_DP_IRQ_HPD_INT_MASK, true);
+	/* enable HDP plug interrupt to prepare for next plugin */
+	dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_PLUG_INT_MASK, true);
 
 	/* uevent will complete disconnection part */
 	mutex_unlock(&dp->event_mutex);
···
 
 	/* irq_hpd can happen at either connected or disconnected state */
 	state =  dp->hpd_state;
-	if (state == ST_DISPLAY_OFF) {
+	if (state == ST_DISPLAY_OFF || state == ST_SUSPENDED) {
 		mutex_unlock(&dp->event_mutex);
 		return 0;
 	}
···
 
 	dp_display->audio_enabled = false;
 
-	dp_ctrl_off(dp->ctrl);
-
-	dp->core_initialized = false;
+	/* triggered by irq_hpd with sink_count = 0 */
+	if (dp->link->sink_count == 0) {
+		dp_ctrl_off_link_stream(dp->ctrl);
+	} else {
+		dp_ctrl_off(dp->ctrl);
+		dp->core_initialized = false;
+	}
 
 	dp_display->power_on = false;