drm: apple: afk: Allow replies after service 'teardown'

'teardown' on DCP's 'av' endpoint's DCPAVAudioInterface is send during
the close afk_service_call.

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

drivers/gpu/drm/apple/afk.c

@@ -308,6 +308,7 @@ static void afk_recv_handle_init(struct apple_dcp_afkep *ep, u32 channel,
 	ch_idx = ep->num_channels++;
 	spin_lock_init(&ep->services[ch_idx].lock);
 	ep->services[ch_idx].enabled = true;
+	ep->services[ch_idx].torndown = false;
 	ep->services[ch_idx].ops = ops;
 	ep->services[ch_idx].ep = ep;
 	ep->services[ch_idx].channel = channel;
@@ -340,7 +341,12 @@ static void afk_recv_handle_teardown(struct apple_dcp_afkep *ep, u32 channel)
 
 	// TODO: think through what locking is necessary
 	spin_lock_irqsave(&service->lock, flags);
-	service->enabled = false;
+	/*
+	 * teardown must not disable the service since since it may be sent as
+	 * side effect of a COMMAND which for which a reply is expected.
+	 * Seen with DCP's "av" endpoint during the close afk_service_call.
+	 */
+	service->torndown = true;
 	ops = service->ops;
 	spin_unlock_irqrestore(&service->lock, flags);
 
@@ -445,6 +451,12 @@ static void afk_recv_handle_std_service(struct apple_dcp_afkep *ep, u32 channel,
 			 ep->endpoint, channel);
 		return;
 	}
+	if (service->torndown) {
+		dev_warn(ep->dcp->dev,
+			 "AFK[ep:%02x]: std service notify on torn down service "
+			 "(chan:%u)\n", ep->endpoint, channel);
+		return;
+	}
 
 	if (type == EPIC_TYPE_NOTIFY && eshdr->category == EPIC_CAT_NOTIFY) {
 		struct epic_std_service_ap_call *call = payload;

drivers/gpu/drm/apple/afk.h

@@ -46,6 +46,7 @@ struct apple_epic_service {
 
 	u32 channel;
 	bool enabled;
+	bool torndown;
 
 	void *cookie;
 

drivers/gpu/drm/apple/av.c

@@ -74,6 +74,8 @@ static void av_interface_teardown(struct apple_epic_service *service)
 	struct apple_dcp *dcp = service->ep->dcp;
 	struct audiosrv_data *asrv = dcp->audiosrv;
 
+	service->enabled = false;
+
 	mutex_lock(&asrv->plug_lock);
 
 	asrv->plugged = false;

drivers/gpu/drm/apple/epic/dpavservep.c

@@ -36,6 +36,8 @@ static void dcpavserv_init(struct apple_epic_service *service, const char *name,
 static void dcpavserv_teardown(struct apple_epic_service *service)
 {
 	struct apple_dcp *dcp = service->ep->dcp;
+	service->enabled = false;
+
 	if (dcp->dcpavserv.enabled) {
 		dcp->dcpavserv.enabled = false;
 		dcp->dcpavserv.service = NULL;
@@ -51,6 +53,7 @@ static void dcpdpserv_init(struct apple_epic_service *service, const char *name,
 
 static void dcpdpserv_teardown(struct apple_epic_service *service)
 {
+	service->enabled = false;
 }
 
 struct dcpavserv_status_report {