ALSA: xen-front: Implement ALSA virtual sound driver
Implement essential initialization of the sound driver:
- introduce required data structures
- handle driver registration
- handle sound card registration
- register sound driver on backend connection
- remove sound driver on backend disconnect
Initialize virtual sound card with streams according to the
Xen store configuration.
Implement ALSA driver operations including:
- manage frontend/backend shared buffers
- manage Xen bus event channel states
Implement requests from front to back for ALSA
PCM operations.
- report ALSA period elapsed event: handle XENSND_EVT_CUR_POS
notifications from the backend when stream position advances
during playback/capture. The event carries a value of how
many octets were played/captured at the time of the event.
- implement explicit stream parameter negotiation between
backend and frontend: handle XENSND_OP_HW_PARAM_QUERY request
to read/update configuration space for the parameter given:
request passes desired parameter interval and the response to
this request returns min/max interval for the parameter to be used.
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/xen/xen_snd_front_evtchnl.c b/sound/xen/xen_snd_front_evtchnl.c
index 1faafff..d70a62e 100644
--- a/sound/xen/xen_snd_front_evtchnl.c
+++ b/sound/xen/xen_snd_front_evtchnl.c
@@ -14,6 +14,7 @@
#include <xen/xenbus.h>
#include "xen_snd_front.h"
+#include "xen_snd_front_alsa.h"
#include "xen_snd_front_cfg.h"
#include "xen_snd_front_evtchnl.h"
@@ -118,7 +119,8 @@ static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id)
switch (event->type) {
case XENSND_EVT_CUR_POS:
- /* Do nothing at the moment. */
+ xen_snd_front_alsa_handle_cur_pos(channel,
+ event->op.cur_pos.position);
break;
}
}