ALSA: hda - Add snd_hda_get_conn_list() helper function

Add a new helper function snd_hda_get_conn_list().
Unlike snd_hda_get_connections(), this function doesn't copy the
connection-list but gives the raw pointer for the cached list.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_codec.c

@@ -311,35 +311,35 @@ EXPORT_SYMBOL_HDA(snd_hda_get_sub_nodes);
 static int _hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
 				hda_nid_t *conn_list, int max_conns);
 static bool add_conn_list(struct snd_array *array, hda_nid_t nid);
-static int copy_conn_list(hda_nid_t nid, hda_nid_t *dst, int max_dst,
-			  hda_nid_t *src, int len);
 
 /**
  * snd_hda_get_connections - get connection list
  * @codec: the HDA codec
  * @nid: NID to parse
- * @conn_list: connection list array
- * @max_conns: max. number of connections to store
+ * @listp: the pointer to store NID list
  *
  * Parses the connection list of the given widget and stores the list
  * of NIDs.
  *
  * Returns the number of connections, or a negative error code.
  */
-int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
-			     hda_nid_t *conn_list, int max_conns)
+int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
+			  const hda_nid_t **listp)
 {
 	struct snd_array *array = &codec->conn_lists;
 	int i, len, old_used;
 	hda_nid_t list[HDA_MAX_CONNECTIONS];
+	hda_nid_t *p;
 
 	/* look up the cached results */
 	for (i = 0; i < array->used; ) {
-		hda_nid_t *p = snd_array_elem(array, i);
+		p = snd_array_elem(array, i);
 		len = p[1];
-		if (nid == *p)
-			return copy_conn_list(nid, conn_list, max_conns,
-					      p + 2, len);
+		if (nid == *p) {
+			if (listp)
+				*listp = p + 2;
+			return len;
+		}
 		i += len + 2;
 	}
 
@@ -355,12 +355,46 @@ int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
 		if (!add_conn_list(array, list[i]))
 			goto error_add;
 
-	return copy_conn_list(nid, conn_list, max_conns, list, len);
+	p = snd_array_elem(array, old_used);
+	if (listp)
+		*listp = p + 2;
+	return len;
 
  error_add:
 	array->used = old_used;
 	return -ENOMEM;
 }
+EXPORT_SYMBOL_HDA(snd_hda_get_conn_list);
+
+/**
+ * snd_hda_get_connections - copy connection list
+ * @codec: the HDA codec
+ * @nid: NID to parse
+ * @conn_list: connection list array
+ * @max_conns: max. number of connections to store
+ *
+ * Parses the connection list of the given widget and stores the list
+ * of NIDs.
+ *
+ * Returns the number of connections, or a negative error code.
+ */
+int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
+			     hda_nid_t *conn_list, int max_conns)
+{
+	const hda_nid_t *list;
+	int len = snd_hda_get_conn_list(codec, nid, &list);
+
+	if (len <= 0)
+		return len;
+	if (len > max_conns) {
+		snd_printk(KERN_ERR "hda_codec: "
+			   "Too many connections %d for NID 0x%x\n",
+			   len, nid);
+		return -EINVAL;
+	}
+	memcpy(conn_list, list, len * sizeof(hda_nid_t));
+	return len;
+}
 EXPORT_SYMBOL_HDA(snd_hda_get_connections);
 
 static int _hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
@@ -471,19 +505,6 @@ static bool add_conn_list(struct snd_array *array, hda_nid_t nid)
 	return true;
 }
 
-static int copy_conn_list(hda_nid_t nid, hda_nid_t *dst, int max_dst,
-			  hda_nid_t *src, int len)
-{
-	if (len > max_dst) {
-		snd_printk(KERN_ERR "hda_codec: "
-			   "Too many connections %d for NID 0x%x\n",
-			   len, nid);
-		return -EINVAL;
-	}
-	memcpy(dst, src, len * sizeof(hda_nid_t));
-	return len;
-}
-
 /**
  * snd_hda_queue_unsol_event - add an unsolicited event to queue
  * @bus: the BUS

sound/pci/hda/hda_codec.h

@@ -903,6 +903,8 @@ int snd_hda_get_sub_nodes(struct hda_codec *codec, hda_nid_t nid,
 			  hda_nid_t *start_id);
 int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
 			    hda_nid_t *conn_list, int max_conns);
+int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
+			  const hda_nid_t **listp);
 int snd_hda_query_supported_pcm(struct hda_codec *codec, hda_nid_t nid,
 				u32 *ratesp, u64 *formatsp, unsigned int *bpsp);