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-rw-r--r--ALSA-afb/Alsa-RegEvt.c309
1 files changed, 309 insertions, 0 deletions
diff --git a/ALSA-afb/Alsa-RegEvt.c b/ALSA-afb/Alsa-RegEvt.c
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+++ b/ALSA-afb/Alsa-RegEvt.c
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+/*
+ * AlsaLibMapping -- provide low level interface with ALSA lib (extracted from alsa-json-gateway code)
+ * Copyright (C) 2015,2016,2017, Fulup Ar Foll fulup@iot.bzh
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+
+*/
+
+#define _GNU_SOURCE // needed for vasprintf
+
+#include "Alsa-ApiHat.h"
+
+// generic sndctrl event handle hook to event callback when pooling
+typedef struct {
+ struct pollfd pfds;
+ sd_event_source *src;
+ snd_ctl_t *ctlDev;
+ int quiet;
+ struct afb_event afbevt;
+} evtHandleT;
+
+typedef struct {
+ int ucount;
+ int cardId;
+ evtHandleT *evtHandle;
+} sndHandleT;
+
+typedef struct {
+ char *apiprefix;
+ char *shortname;
+}cardRegistryT;
+
+cardRegistryT *cardRegistry[MAX_SND_CARD+1];
+
+// This routine is called when ALSA event are fired
+STATIC int sndCtlEventCB (sd_event_source* src, int fd, uint32_t revents, void* userData) {
+ int err;
+ evtHandleT *evtHandle = (evtHandleT*)userData;
+ snd_ctl_event_t *eventId;
+ json_object *ctlEventJ;
+ unsigned int mask;
+ int iface;
+ int device;
+ int subdev;
+ const char*devname;
+ ctlRequestT ctlRequest;
+ snd_ctl_elem_id_t *elemId;
+
+ if ((revents & EPOLLHUP) != 0) {
+ AFB_NOTICE( "SndCtl hanghup [car disconnected]");
+ goto ExitOnSucess;
+ }
+
+ if ((revents & EPOLLIN) != 0) {
+
+ // initialise event structure on stack
+ snd_ctl_event_alloca(&eventId);
+ snd_ctl_elem_id_alloca(&elemId);
+
+ err = snd_ctl_read(evtHandle->ctlDev, eventId);
+ if (err < 0) goto OnErrorExit;
+
+ // we only process sndctrl element
+ if (snd_ctl_event_get_type(eventId) != SND_CTL_EVENT_ELEM) goto ExitOnSucess;
+
+ // we only process value changed events
+ mask = snd_ctl_event_elem_get_mask(eventId);
+ if (!(mask & SND_CTL_EVENT_MASK_VALUE)) goto ExitOnSucess;
+
+ snd_ctl_event_elem_get_id (eventId, elemId);
+
+ err = alsaGetSingleCtl (evtHandle->ctlDev, elemId, &ctlRequest, evtHandle->quiet);
+ if (err) goto OnErrorExit;
+
+ iface = snd_ctl_event_elem_get_interface(eventId);
+ device = snd_ctl_event_elem_get_device(eventId);
+ subdev = snd_ctl_event_elem_get_subdevice(eventId);
+ devname= snd_ctl_event_elem_get_name(eventId);
+
+ // proxy ctlevent as a binder event
+ ctlEventJ = json_object_new_object();
+ json_object_object_add(ctlEventJ, "device" ,json_object_new_int (device));
+ json_object_object_add(ctlEventJ, "subdev" ,json_object_new_int (subdev));
+ if (evtHandle->quiet < 2) {
+ json_object_object_add(ctlEventJ, "iface" ,json_object_new_int (iface));
+ json_object_object_add(ctlEventJ, "devname",json_object_new_string (devname));
+ }
+ if (ctlRequest.jValues) (json_object_object_add(ctlEventJ, "values" ,ctlRequest.jValues));
+ AFB_DEBUG( "sndCtlEventCB=%s", json_object_get_string(ctlEventJ));
+ afb_event_push(evtHandle->afbevt, ctlEventJ);
+ }
+
+ ExitOnSucess:
+ return 0;
+
+ OnErrorExit:
+ WARNING ("sndCtlEventCB: ignored unsupported event type");
+ return (0);
+}
+
+// Subscribe to every Alsa CtlEvent send by a given board
+PUBLIC void alsaEvtSubcribe (afb_req request) {
+ static sndHandleT sndHandles[MAX_SND_CARD];
+ evtHandleT *evtHandle;
+ snd_ctl_t *ctlDev;
+ int err, idx, cardId, idxFree=-1;
+ snd_ctl_card_info_t *cardinfo;
+ queryValuesT queryValues;
+
+
+ err = alsaCheckQuery (request, &queryValues);
+ if (err) goto OnErrorExit;
+
+
+ // open control interface for devid
+ err = snd_ctl_open(&ctlDev, queryValues.devid, SND_CTL_READONLY);
+ if (err < 0) {
+ ctlDev=NULL;
+ afb_req_fail_f (request, "devid-unknown", "SndCard devid=%s Not Found err=%s", queryValues.devid, snd_strerror(err));
+ goto OnErrorExit;
+ }
+
+ snd_ctl_card_info_alloca(&cardinfo);
+ if ((err = snd_ctl_card_info(ctlDev, cardinfo)) < 0) {
+ afb_req_fail_f (request, "devid-invalid", "SndCard devid=%s Not Found err=%s", queryValues.devid, snd_strerror(err));
+ goto OnErrorExit;
+ }
+
+ cardId=snd_ctl_card_info_get_card(cardinfo);
+
+ // search for an existing subscription and mark 1st free slot
+ for (idx= 0; idx < MAX_SND_CARD; idx ++) {
+ if (sndHandles[idx].ucount > 0 && cardId == sndHandles[idx].cardId) {
+ evtHandle= sndHandles[idx].evtHandle;
+ break;
+ } else if (idxFree == -1) idxFree= idx;
+ };
+
+ // if not subscription exist for the event let's create one
+ if (idx == MAX_SND_CARD) {
+
+ // reach MAX_SND_CARD event registration
+ if (idxFree == -1) {
+ afb_req_fail_f (request, "register-toomany", "Cannot register new event Maxcard==%d", idx);
+ goto OnErrorExit;
+ }
+
+ evtHandle = malloc (sizeof(evtHandleT));
+ evtHandle->ctlDev = ctlDev;
+ evtHandle->quiet = queryValues.quiet;
+ sndHandles[idxFree].ucount = 0;
+ sndHandles[idxFree].cardId = cardId;
+ sndHandles[idxFree].evtHandle = evtHandle;
+
+ // subscribe for sndctl events attached to devid
+ err = snd_ctl_subscribe_events(evtHandle->ctlDev, 1);
+ if (err < 0) {
+ afb_req_fail_f (request, "subscribe-fail", "Cannot subscribe events from devid=%s err=%d", queryValues.devid, err);
+ goto OnErrorExit;
+ }
+
+ // get pollfd attach to this sound board
+ snd_ctl_poll_descriptors(evtHandle->ctlDev, &evtHandle->pfds, 1);
+
+ // register sound event to binder main loop
+ err = sd_event_add_io(afb_daemon_get_event_loop(), &evtHandle->src, evtHandle->pfds.fd, EPOLLIN, sndCtlEventCB, evtHandle);
+ if (err < 0) {
+ afb_req_fail_f (request, "register-mainloop", "Cannot hook events to mainloop devid=%s err=%d", queryValues.devid, err);
+ goto OnErrorExit;
+ }
+
+ // create binder event attached to devid name
+ evtHandle->afbevt = afb_daemon_make_event (queryValues.devid);
+ if (!afb_event_is_valid (evtHandle->afbevt)) {
+ afb_req_fail_f (request, "register-event", "Cannot register new binder event name=%s", queryValues.devid);
+ goto OnErrorExit;
+ }
+
+ // everything looks OK let's move forward
+ idx=idxFree;
+ }
+
+ // subscribe to binder event
+ err = afb_req_subscribe(request, evtHandle->afbevt);
+ if (err != 0) {
+ afb_req_fail_f (request, "register-eventname", "Cannot subscribe binder event name=%s [invalid channel]", queryValues.devid);
+ goto OnErrorExit;
+ }
+
+ // increase usage count and return success
+ sndHandles[idx].ucount ++;
+ afb_req_success(request, NULL, NULL);
+ return;
+
+ OnErrorExit:
+ if (ctlDev) snd_ctl_close(ctlDev);
+ return;
+}
+
+// Subscribe to every Alsa CtlEvent send by a given board
+PUBLIC void alsaGetCardId (afb_req request) {
+ char devid [10];
+ const char *devname, *shortname, *longname;
+ int card, err, index, idx;
+ json_object *respJson;
+ snd_ctl_t *ctlDev;
+ snd_ctl_card_info_t *cardinfo;
+
+ const char *sndname = afb_req_value(request, "sndname");
+ if (sndname == NULL) {
+ afb_req_fail_f (request, "argument-missing", "sndname=SndCardName missing");
+ goto OnErrorExit;
+ }
+
+ // loop on potential card number
+ snd_ctl_card_info_alloca(&cardinfo);
+ for (card =0; card < MAX_SND_CARD; card++) {
+
+ // build card devid and probe it
+ snprintf (devid, sizeof(devid), "hw:%i", card);
+
+ // open control interface for devid
+ err = snd_ctl_open(&ctlDev, devid, SND_CTL_READONLY);
+ if (err < 0) continue;
+
+ // extract sound card information
+ snd_ctl_card_info(ctlDev, cardinfo);
+ index = snd_ctl_card_info_get_card(cardinfo);
+ devname = snd_ctl_card_info_get_id(cardinfo);
+ shortname= snd_ctl_card_info_get_name(cardinfo);
+ longname = snd_ctl_card_info_get_longname(cardinfo);
+
+ // check if short|long name match
+ if (!strcmp (sndname, devname)) break;
+ if (!strcmp (sndname, shortname)) break;
+ if (!strcmp (sndname, longname)) break;
+ }
+
+ if (card == MAX_SND_CARD) {
+ afb_req_fail_f (request, "ctlDev-notfound", "Fail to find card with name=%s", sndname);
+ goto OnErrorExit;
+ }
+
+ // proxy ctlevent as a binder event
+ respJson = json_object_new_object();
+ json_object_object_add(respJson, "index" ,json_object_new_int (index));
+ json_object_object_add(respJson, "devid" ,json_object_new_string (devid));
+ json_object_object_add(respJson, "shortname" ,json_object_new_string (shortname));
+ json_object_object_add(respJson, "longname" ,json_object_new_string (longname));
+
+ // search for a HAL binder card mapping name to api prefix
+ for (idx=0; idx < MAX_SND_CARD; idx++) {
+ if (!strcmp (cardRegistry[idx]->shortname, shortname)) break;
+ }
+ // if a match if found, then we have an HAL for this board let's return its value
+ if (idx < MAX_SND_CARD) json_object_object_add(respJson, "halapi",json_object_new_string (cardRegistry[idx]->apiprefix));
+
+ afb_req_success(request, respJson, NULL);
+ return;
+
+ OnErrorExit:
+ return;
+}
+
+// Register loaded HAL with board Name and API prefix
+PUBLIC void alsaRegisterHal (afb_req request) {
+ static int index=0;
+ const char *shortname, *apiPrefix;
+
+ apiPrefix = afb_req_value(request, "prefix");
+ if (apiPrefix == NULL) {
+ afb_req_fail_f (request, "argument-missing", "prefix=BindingApiPrefix missing");
+ goto OnErrorExit;
+ }
+
+ shortname = afb_req_value(request, "sndname");
+ if (shortname == NULL) {
+ afb_req_fail_f (request, "argument-missing", "sndname=SndCardName missing");
+ goto OnErrorExit;
+ }
+
+ if (index == MAX_SND_CARD) {
+ afb_req_fail_f (request, "alsahal-toomany", "Fail to register sndname=[%s]", shortname);
+ goto OnErrorExit;
+ }
+
+ cardRegistry[index]= malloc (sizeof(cardRegistry));
+ cardRegistry[index]->apiprefix=strdup(apiPrefix);
+ cardRegistry[index]->shortname=strdup(shortname);
+ index++;cardRegistry[index]=NULL;
+
+ // If OK return sound card Alsa ID+Info
+ alsaGetCardId(request);
+ return;
+
+ OnErrorExit:
+ return;
+}
+