drm/msm/dp: validate audio ops in cable disconnect path

There is possiblity for accessing invalid audio ops when
hpd unplug is processed in between dp_display_enable
and dp_display_post_enable functions. This change adds
the validation for audio ops before accessing them and
clears audio_supported variable after processing
dp_audio_off functionality to initialize the variable to
correct state.

CRs-Fixed: 2243808
Change-Id: I103329ec5a922e5a16ce45388b3c09165b97b757
Signed-off-by: Govinda Rajulu Chenna <gchenna@codeaurora.org>

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

@@ -669,6 +669,9 @@ static int dp_audio_notify(struct dp_audio_private *audio, u32 state)
 	int rc = 0;
 	struct msm_ext_disp_init_data *ext = &audio->ext_audio_data;
 
+	if (!ext->intf_ops.audio_notify)
+		goto end;
+
 	rc = ext->intf_ops.audio_notify(audio->ext_pdev,
 			&ext->codec, state);
 	if (rc) {
@@ -710,12 +713,14 @@ static int dp_audio_on(struct dp_audio *dp_audio)
 
 	audio->session_on = true;
 
-	rc = ext->intf_ops.audio_config(audio->ext_pdev,
-			&ext->codec,
-			EXT_DISPLAY_CABLE_CONNECT);
-	if (rc) {
-		pr_err("failed to config audio, err=%d\n", rc);
-		goto end;
+	if (ext->intf_ops.audio_config) {
+		rc = ext->intf_ops.audio_config(audio->ext_pdev,
+				&ext->codec,
+				EXT_DISPLAY_CABLE_CONNECT);
+		if (rc) {
+			pr_err("failed to config audio, err=%d\n", rc);
+			goto end;
+		}
 	}
 
 	rc = dp_audio_notify(audio, EXT_DISPLAY_CABLE_CONNECT);
@@ -752,11 +757,13 @@ static int dp_audio_off(struct dp_audio *dp_audio)
 
 	pr_debug("success\n");
 end:
-	rc = ext->intf_ops.audio_config(audio->ext_pdev,
-			&ext->codec,
-			EXT_DISPLAY_CABLE_DISCONNECT);
-	if (rc)
-		pr_err("failed to config audio, err=%d\n", rc);
+	if (ext->intf_ops.audio_config) {
+		rc = ext->intf_ops.audio_config(audio->ext_pdev,
+				&ext->codec,
+				EXT_DISPLAY_CABLE_DISCONNECT);
+		if (rc)
+			pr_err("failed to config audio, err=%d\n", rc);
+	}
 
 	audio->session_on = false;
 	audio->engine_on  = false;

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

@@ -632,8 +632,11 @@ static int dp_display_process_hpd_low(struct dp_display_private *dp)
 	int rc = 0, idx;
 	struct dp_panel *dp_panel;
 
+	mutex_lock(&dp->session_lock);
+
 	if (!dp->dp_display.is_connected) {
 		pr_debug("HPD already off\n");
+		mutex_unlock(&dp->session_lock);
 		return 0;
 	}
 
@@ -646,10 +649,14 @@ static int dp_display_process_hpd_low(struct dp_display_private *dp)
 
 		dp_panel = dp->active_panels[idx];
 
-		if (dp_panel->audio_supported)
+		if (dp_panel->audio_supported) {
 			dp_panel->audio->off(dp_panel->audio);
+			dp_panel->audio_supported = false;
+		}
 	}
 
+	mutex_unlock(&dp->session_lock);
+
 	dp_display_process_mst_hpd_low(dp);
 
 	rc = dp_display_send_hpd_notification(dp, false);