/*
* AlsaUseCase -- 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.
*
* References:
* https://kernel.readthedocs.io/en/sphinx-samples/writing-an-alsa-driver.html#control-names
* https://01.org/linuxgraphics/gfx-docs/drm/sound/designs/control-names.html
*/
#define _GNU_SOURCE // needed for vasprintf
#include <alsa/asoundlib.h>
#include <alsa/sound/tlv.h>
#include <systemd/sd-event.h>
#include <sys/ioctl.h>
#include "Alsa-ApiHat.h"
// Performs like a toggle switch for attenuation, because they're bool (ref:user-ctl-element-set.c)
static const unsigned int *allocate_bool_elem_set_tlv (void) {
static const SNDRV_CTL_TLVD_DECLARE_DB_MINMAX(range, -10000, 0);
unsigned int *tlv= malloc(sizeof(range));
if (tlv == NULL) return NULL;
memcpy(tlv, range, sizeof(range));
return tlv;
}
STATIC json_object * addOneSndCtl(afb_req request, snd_ctl_t *ctlDev, json_object *ctlJ, halQueryMode queryMode) {
int err, ctlNumid;
json_object *tmpJ;
const char *ctlName;
ctlRequestT ctlRequest;
int ctlMax, ctlMin, ctlStep, ctlCount, ctlSubDev, ctlSndDev;
snd_ctl_elem_type_t ctlType;
snd_ctl_elem_info_t *elemInfo;
snd_ctl_elem_id_t *elemId;
snd_ctl_elem_value_t *elemValue;
const unsigned int *elemTlv=NULL;
// parse json ctl object
json_object_object_get_ex (ctlJ, "name" , &tmpJ);
ctlName = json_object_get_string(tmpJ);
json_object_object_get_ex (ctlJ, "numid" , &tmpJ);
ctlNumid = json_object_get_int(tmpJ);
if (!ctlNumid && !ctlName) {
afb_req_fail_f (request, "ctl-invalid", "crl=%s name or numid missing", json_object_get_string(ctlJ));
goto OnErrorExit;
}
// Assert that this ctls is not used
snd_ctl_elem_info_alloca(&elemInfo);
if (ctlName) snd_ctl_elem_info_set_name (elemInfo, ctlName);
if (ctlNumid)snd_ctl_elem_info_set_numid(elemInfo, ctlNumid);
snd_ctl_elem_info_set_interface (elemInfo, SND_CTL_ELEM_IFACE_MIXER);
err = snd_ctl_elem_info(ctlDev, elemInfo);
if (!err) {
snd_ctl_elem_id_alloca(&elemId);
snd_ctl_elem_info_get_id(elemInfo, elemId);
if (ctlNumid) goto OnSucessExit; // hardware control nothing todo
else { // user created kcontrol should be removable
err = snd_ctl_elem_remove(ctlDev, elemId);
AFB_NOTICE ("ctlName=%s numid=%d fail to reset", snd_ctl_elem_info_get_name(elemInfo), snd_ctl_elem_info_get_numid(elemInfo));
goto OnErrorExit;
}
}
// default for json_object_get_int is zero
json_object_object_get_ex (ctlJ, "min" , &tmpJ);
ctlMin = json_object_get_int(tmpJ);
json_object_object_get_ex (ctlJ, "max" , &tmpJ);
if (!tmpJ) ctlMax=1;
else ctlMax = json_object_get_int(tmpJ);
json_object_object_get_ex (ctlJ, "step" , &tmpJ);
if (!tmpJ) ctlStep=1;
else ctlStep = json_object_get_int(tmpJ);
json_object_object_get_ex (ctlJ, "count" , &tmpJ);
if (!tmpJ) ctlCount=2;
else ctlCount = json_object_get_int(tmpJ);
json_object_object_get_ex (ctlJ, "snddev" , &tmpJ);
ctlSndDev = json_object_get_int(tmpJ);
json_object_object_get_ex (ctlJ, "subdev" , &tmpJ);
ctlSubDev = json_object_get_int(tmpJ);
json_object_object_get_ex (ctlJ, "type" , &tmpJ);
if (!tmpJ) ctlType=SND_CTL_ELEM_TYPE_BOOLEAN;
else ctlType = json_object_get_int(tmpJ);
// Add requested ID into elemInfo
snd_ctl_elem_info_set_device(elemInfo, ctlSndDev);
snd_ctl_elem_info_set_subdevice(elemInfo, ctlSubDev);
// prepare value set
snd_ctl_elem_value_alloca(&elemValue);
switch (ctlType) {
case SND_CTL_ELEM_TYPE_BOOLEAN:
err = snd_ctl_add_boolean_elem_set(ctlDev, elemInfo, 1, ctlCount);
if (err) {
afb_req_fail_f (request, "ctl-invalid-bool", "devid=%s crl=%s invalid boolean data", snd_ctl_name(ctlDev), json_object_get_string(ctlJ));
goto OnErrorExit;
}
elemTlv = allocate_bool_elem_set_tlv();
// Provide FALSE as default value
for (int idx=0; idx < ctlCount; idx ++) {
snd_ctl_elem_value_set_boolean (elemValue, idx, 1);
}
break;
case SND_CTL_ELEM_TYPE_INTEGER:
err = snd_ctl_add_integer_elem_set (ctlDev, elemInfo, 1, ctlCount, ctlMin, ctlMax, ctlStep);
if (err) {
afb_req_fail_f (request, "ctl-invalid-bool", "devid=%s crl=%s invalid boolean data", snd_ctl_name(ctlDev), json_object_get_string(ctlJ));
goto OnErrorExit;
}
// Provide 0 as default value
for (int idx=0; idx < ctlCount; idx ++) {
snd_ctl_elem_value_set_integer (elemValue, idx, 0);
}
break;
case SND_CTL_ELEM_TYPE_INTEGER64:
err = snd_ctl_add_integer64_elem_set (ctlDev, elemInfo, 1, ctlCount, ctlMin, ctlMax, ctlStep);
if (err) {
afb_req_fail_f (request, "ctl-invalid-bool", "devid=%s crl=%s invalid boolean data", snd_ctl_name(ctlDev), json_object_get_string(ctlJ));
goto OnErrorExit;
}
// Provide 0 as default value
for (int idx=0; idx < ctlCount; idx ++) {
snd_ctl_elem_value_set_integer64 (elemValue, idx, 0);
}
break;
case SND_CTL_ELEM_TYPE_ENUMERATED:
case SND_CTL_ELEM_TYPE_BYTES:
default:
afb_req_fail_f (request, "ctl-invalid-type", "crl=%s invalid/unknown type", json_object_get_string(ctlJ));
goto OnErrorExit;
}
// write default values in newly created control
snd_ctl_elem_id_alloca(&elemId);
snd_ctl_elem_info_get_id(elemInfo, elemId);
snd_ctl_elem_value_set_id(elemValue, elemId);
err = snd_ctl_elem_write (ctlDev, elemValue);
if (err < 0) {
afb_req_fail_f (request, "ctl-write-fail", "crl=%s numid=%d fail to write data error=%s", json_object_get_string(ctlJ), snd_ctl_elem_info_get_numid(elemInfo), snd_strerror(err));
goto OnErrorExit;
}
// write a default null TLV (if usefull should be implemented for every ctl type)
if (elemTlv) {
err=snd_ctl_elem_tlv_write (ctlDev, elemId, elemTlv);
if (err < 0) {
afb_req_fail_f (request, "TLV-write-fail", "crl=%s numid=%d fail to write data error=%s", json_object_get_string(ctlJ), snd_ctl_elem_info_get_numid(elemInfo), snd_strerror(err));
goto OnErrorExit;
}
}
// return newly created as a JSON object
OnSucessExit:
alsaGetSingleCtl (ctlDev, elemId, &ctlRequest, queryMode);
if (ctlRequest.used < 0) goto OnErrorExit;
return ctlRequest.valuesJ;
OnErrorExit:
return NULL;
}
PUBLIC void alsaAddCustomCtls(afb_req request) {
int err;
json_object *ctlsJ, *ctlsValues, *ctlValues;
enum json_type;
snd_ctl_t *ctlDev=NULL;
const char *devid, *mode;
devid = afb_req_value(request, "devid");
if (devid == NULL) {
afb_req_fail_f (request, "devid-missing", "devid MUST be defined for alsaAddCustomCtls");
goto OnErrorExit;
}
// open control interface for devid
err = snd_ctl_open(&ctlDev, devid, 0);
if (err < 0) {
afb_req_fail_f (request, "devid-unknown", "SndCard devid=[%s] Not Found err=%s", devid, snd_strerror(err));
goto OnErrorExit;
}
// get verbosity level
halQueryMode queryMode = QUERY_QUIET;
mode = afb_req_value(request, "mode");
if (mode != NULL) {
sscanf(mode,"%i", (int*)&queryMode);
}
// extract sound controls and parse json
ctlsJ = json_tokener_parse (afb_req_value(request, "ctl"));
if (!ctlsJ) {
afb_req_fail_f (request, "ctls-missing", "ctls MUST be defined as a JSON array for alsaAddCustomCtls");
goto OnErrorExit;
}
switch (json_object_get_type(ctlsJ)) {
case json_type_object:
ctlsValues= addOneSndCtl(request, ctlDev, ctlsJ, queryMode);
break;
case json_type_array:
ctlsValues= json_object_new_array();
for (int idx= 0; idx < json_object_array_length (ctlsJ); idx++) {
json_object *ctlJ = json_object_array_get_idx (ctlsJ, idx);
ctlValues= addOneSndCtl(request, ctlDev, ctlJ, queryMode) ;
if (ctlValues) json_object_array_add (ctlsValues, ctlValues);
}
break;
default:
afb_req_fail_f (request, "ctls-invalid","ctls=%s not valid JSON array", json_object_get_string(ctlsJ));
goto OnErrorExit;
}
// get ctl as a json response
afb_req_success(request, ctlsValues, NULL);
OnErrorExit:
if (ctlDev) snd_ctl_close(ctlDev);
return;
}