ALSA: firewire-lib: add a kernel API to stop a couple of AMDTP streams in AMDTP domain

This commit adds a kernel API to stop a couple of isochronous contexts
for AMDTP streams. The API is not protected with any lock primitive.
Callers should use this with enough lock against concurrent access.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/amdtp-stream.c

@@ -1158,3 +1158,19 @@ void amdtp_domain_destroy(struct amdtp_domain *d)
 	WARN_ON(!list_empty(&d->streams));
 }
 EXPORT_SYMBOL_GPL(amdtp_domain_destroy);
+
+/**
+ * amdtp_domain_stop - stop sending packets for isoc context in the same domain.
+ * @d: the AMDTP domain to which the isoc contexts belong.
+ */
+void amdtp_domain_stop(struct amdtp_domain *d)
+{
+	struct amdtp_stream *s, *next;
+
+	list_for_each_entry_safe(s, next, &d->streams, list) {
+		list_del(&s->list);
+
+		amdtp_stream_stop(s);
+	}
+}
+EXPORT_SYMBOL_GPL(amdtp_domain_stop);

sound/firewire/amdtp-stream.h

@@ -170,6 +170,9 @@ struct amdtp_stream {
 	/* For backends to process data blocks. */
 	void *protocol;
 	amdtp_stream_process_ctx_payloads_t process_ctx_payloads;
+
+	// For domain.
+	struct list_head list;
 };
 
 int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
@@ -274,4 +277,6 @@ struct amdtp_domain {
 int amdtp_domain_init(struct amdtp_domain *d);
 void amdtp_domain_destroy(struct amdtp_domain *d);
 
+void amdtp_domain_stop(struct amdtp_domain *d);
+
 #endif