+
+int snd_hdac_ext_bus_link_get(struct hdac_ext_bus *ebus,
+ struct hdac_ext_link *link)
+{
+ int ret = 0;
+
+ mutex_lock(&ebus->lock);
+
+ /*
+ * if we move from 0 to 1, count will be 1 so power up this link
+ * as well, also check the dma status and trigger that
+ */
+ if (++link->ref_count == 1) {
+ if (!ebus->cmd_dma_state) {
+ snd_hdac_bus_init_cmd_io(&ebus->bus);
+ ebus->cmd_dma_state = true;
+ }
+
+ ret = snd_hdac_ext_bus_link_power_up(link);
+ }
+
+ mutex_unlock(&ebus->lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_get);
+
+int snd_hdac_ext_bus_link_put(struct hdac_ext_bus *ebus,
+ struct hdac_ext_link *link)
+{
+ int ret = 0;
+ struct hdac_ext_link *hlink;
+ bool link_up = false;
+
+ mutex_lock(&ebus->lock);
+
+ /*
+ * if we move from 1 to 0, count will be 0
+ * so power down this link as well
+ */
+ if (--link->ref_count == 0) {
+ ret = snd_hdac_ext_bus_link_power_down(link);
+
+ /*
+ * now check if all links are off, if so turn off
+ * cmd dma as well
+ */
+ list_for_each_entry(hlink, &ebus->hlink_list, list) {
+ if (hlink->ref_count) {
+ link_up = true;
+ break;
+ }
+ }
+
+ if (!link_up) {
+ snd_hdac_bus_stop_cmd_io(&ebus->bus);
+ ebus->cmd_dma_state = false;
+ }
+ }
+
+ mutex_unlock(&ebus->lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_put);