drm/msm/dp: unplug interrupt missed after irq_hpd handler

There is HPD unplug interrupts missed at scenario of an irq_hpd
followed by unplug interrupts with around 10 ms in between.
Since both AUX_SW_RESET and DP_SW_RESET clear pending HPD interrupts,
irq_hpd handler should not issues either aux or sw reset to avoid
following unplug interrupt be cleared accidentally. This patch
also postpone handling of irq_hpd until connected state if it
happened at connection pending state.

Changes in V2:
-- add postpone handling of irq_hpd until connected state
-- check DP_TRAINING_1 instead of DP_TRAINING_NONE

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

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

@@ -336,7 +336,6 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
 	ssize_t ret;
 	int const aux_cmd_native_max = 16;
 	int const aux_cmd_i2c_max = 128;
-	int const retry_count = 5;
 	struct dp_aux_private *aux = container_of(dp_aux,
 		struct dp_aux_private, dp_aux);
 
@@ -378,12 +377,6 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
 	ret = dp_aux_cmd_fifo_tx(aux, msg);
 
 	if (ret < 0) {
-		if (aux->native) {
-			aux->retry_cnt++;
-			if (!(aux->retry_cnt % retry_count))
-				dp_catalog_aux_update_cfg(aux->catalog);
-			dp_catalog_aux_reset(aux->catalog);
-		}
 		usleep_range(400, 500); /* at least 400us to next try */
 		goto unlock_exit;
 	}

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

@@ -190,6 +190,18 @@ int dp_catalog_aux_clear_hw_interrupts(struct dp_catalog *dp_catalog)
 	return 0;
 }
 
+/**
+ * dp_catalog_aux_reset() - reset AUX controller
+ *
+ * @aux: DP catalog structure
+ *
+ * return: void
+ *
+ * This function reset AUX controller
+ *
+ * NOTE: reset AUX controller will also clear any pending HPD related interrupts
+ * 
+ */
 void dp_catalog_aux_reset(struct dp_catalog *dp_catalog)
 {
 	u32 aux_ctrl;
@@ -483,6 +495,18 @@ int dp_catalog_ctrl_set_pattern(struct dp_catalog *dp_catalog,
 	return 0;
 }
 
+/**
+ * dp_catalog_ctrl_reset() - reset DP controller
+ *
+ * @dp_catalog: DP catalog structure
+ *
+ * return: void
+ *
+ * This function reset the DP controller
+ *
+ * NOTE: reset DP controller will also clear any pending HPD related interrupts
+ * 
+ */
 void dp_catalog_ctrl_reset(struct dp_catalog *dp_catalog)
 {
 	u32 sw_reset;

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

@@ -1296,6 +1296,7 @@ static int dp_ctrl_setup_main_link(struct dp_ctrl_private *ctrl,
 	 * transitioned to PUSH_IDLE. In order to start transmitting
 	 * a link training pattern, we have to first do soft reset.
 	 */
+	if (*training_step == DP_TRAINING_1)
 		dp_catalog_ctrl_reset(ctrl->catalog);
 
 	ret = dp_ctrl_link_train(ctrl, cr, training_step);
@@ -1491,15 +1492,18 @@ static int dp_ctrl_deinitialize_mainlink(struct dp_ctrl_private *ctrl)
 	return 0;
 }
 
+static void dp_ctrl_link_idle_reset(struct dp_ctrl_private *ctrl)
+{
+	dp_ctrl_push_idle(&ctrl->dp_ctrl);
+	dp_catalog_ctrl_reset(ctrl->catalog);
+}
+
 static int dp_ctrl_link_maintenance(struct dp_ctrl_private *ctrl)
 {
 	int ret = 0;
 	struct dp_cr_status cr;
 	int training_step = DP_TRAINING_NONE;
 
-	dp_ctrl_push_idle(&ctrl->dp_ctrl);
-	dp_catalog_ctrl_reset(ctrl->catalog);
-
 	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
 
 	ret = dp_ctrl_setup_main_link(ctrl, &cr, &training_step);
@@ -1626,6 +1630,7 @@ void dp_ctrl_handle_sink_request(struct dp_ctrl *dp_ctrl)
 
 	if (sink_request & DP_TEST_LINK_TRAINING) {
 		dp_link_send_test_response(ctrl->link);
+		dp_ctrl_link_idle_reset(ctrl);
 		if (dp_ctrl_link_maintenance(ctrl)) {
 			DRM_ERROR("LM failed: TEST_LINK_TRAINING\n");
 			return;
@@ -1679,7 +1684,7 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 			break;
 		}
 
-		training_step = DP_TRAINING_NONE;
+		training_step = DP_TRAINING_1;
 		rc = dp_ctrl_setup_main_link(ctrl, &cr, &training_step);
 		if (rc == 0) {
 			/* training completed successfully */

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

@@ -700,6 +700,13 @@ static int dp_irq_hpd_handle(struct dp_display_private *dp, u32 data)
 		return 0;
 	}
 
+	if (state == ST_CONNECT_PENDING) {
+		/* wait until ST_CONNECTED */
+		dp_add_event(dp, EV_IRQ_HPD_INT, 0, 1); /* delay = 1 */
+		mutex_unlock(&dp->event_mutex);
+		return 0;
+	}
+
 	ret = dp_display_usbpd_attention_cb(&dp->pdev->dev);
 	if (ret == -ECONNRESET) { /* cable unplugged */
 		dp->core_initialized = false;