1 files changed, 399 insertions, 0 deletions
diff --git a/alsa-binding/Alsa-AddCtl.c b/alsa-binding/Alsa-AddCtl.c
new file mode 100644
index 0000000..3f969c1
--- /dev/null
+++ b/alsa-binding/Alsa-AddCtl.c
@@ -0,0 +1,399 @@
+/*
+ * 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)
+
+#ifndef SNDRV_CTL_TLVD_DECLARE_DB_MINMAX
+// taken from alsa-lib-1.1.3:include/sound/tlv.h
+
+#define SNDRV_CTL_TLVD_LENGTH(...) \
+    ((unsigned int)sizeof((const unsigned int[]) { __VA_ARGS__ }))
+
+#define SNDRV_CTL_TLVD_ITEM(type, ...) \
+    (type), SNDRV_CTL_TLVD_LENGTH(__VA_ARGS__), __VA_ARGS__
+
+#define SNDRV_CTL_TLVT_DB_MINMAX 4
+
+#define SNDRV_CTL_TLVD_DB_MINMAX_ITEM(min_dB, max_dB) \
+    SNDRV_CTL_TLVD_ITEM(SNDRV_CTL_TLVT_DB_MINMAX, (min_dB), (max_dB))
+
+#define SNDRV_CTL_TLVD_DECLARE_DB_MINMAX(name, min_dB, max_dB) \
+    unsigned int name[] = { \
+        SNDRV_CTL_TLVD_DB_MINMAX_ITEM(min_dB, max_dB) \
+    }
+
+#define SNDRV_CTL_TLVD_DB_SCALE_MASK    0xffff
+#define SNDRV_CTL_TLVD_DB_SCALE_MUTE    0x10000
+
+#endif
+static const unsigned int *allocate_bool_fake_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 const unsigned int *allocate_int_dbscale_tlv(int min, int step, int mute) {
+    // SNDRV_CTL_TLVD_DECLARE_DB_SCALE(range, min, step, mute);
+    size_t tlvSize = sizeof (4 * sizeof (unsigned int));
+    unsigned int *tlv = malloc(tlvSize);
+    tlv[0] = SNDRV_CTL_TLVT_DB_LINEAR;
+    tlv[1] = (int) tlvSize;
+    tlv[2] = min * 100;
+    tlv[3] = ((step * 100) & SNDRV_CTL_TLVD_DB_SCALE_MASK) | ((mute * 100) ? SNDRV_CTL_TLVD_DB_SCALE_MUTE : 0);
+    return tlv;
+}
+
+static const unsigned int *allocate_int_linear_tlv(int max, int min) {
+    // SNDRV_CTL_TLVD_DECLARE_DB_LINEAR (range, min, max);
+    size_t tlvSize = sizeof (4 * sizeof (unsigned int));
+    unsigned int *tlv = malloc(tlvSize);
+    tlv[0] = SNDRV_CTL_TLVT_DB_LINEAR;
+    tlv[1] = (int) tlvSize;
+    tlv[2] = -min * 100;
+    tlv[3] = max * 100;
+    return tlv;
+}
+
+STATIC json_object * addOneSndCtl(afb_req request, snd_ctl_t *ctlDev, json_object *ctlJ, queryModeE queryMode) {
+    int err, done, ctlNumid, ctlValue=0, shouldCreate;
+    json_object *tmpJ;
+    const char *ctlName;
+    ctlRequestT ctlRequest;
+    int ctlMax=100, ctlMin=0, ctlStep, ctlCount, ctlSubDev=0, ctlSndDev=0;
+    snd_ctl_elem_type_t ctlType=SND_CTL_ELEM_TYPE_NONE;
+    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, "ctl", &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;
+    }
+
+
+    // We are facing a software ctl
+    if (ctlNumid == CTL_AUTO) {
+        done = json_object_object_get_ex(ctlJ, "type", &tmpJ);
+        if (done) ctlType = json_object_get_int(tmpJ);
+        else ctlType = SND_CTL_ELEM_TYPE_INTEGER;
+
+        json_object_object_get_ex(ctlJ, "val", &tmpJ);
+        ctlValue = json_object_get_int(tmpJ);
+
+        // default for json_object_get_int is zero
+        json_object_object_get_ex(ctlJ, "min", &tmpJ);
+        ctlMin = json_object_get_int(tmpJ);
+
+        done = json_object_object_get_ex(ctlJ, "max", &tmpJ);
+        if (done) ctlMax = json_object_get_int(tmpJ);
+        else {
+            if (ctlType == SND_CTL_ELEM_TYPE_BOOLEAN) ctlMax = 1;
+            else ctlMax = 100;
+        }
+
+        done = json_object_object_get_ex(ctlJ, "step", &tmpJ);
+        if (!done) ctlStep = 1;
+        else ctlStep = json_object_get_int(tmpJ);
+
+        done = json_object_object_get_ex(ctlJ, "count", &tmpJ);
+        if (!done) ctlCount = 1;
+        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);
+    }
+
+    // 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 > 0)snd_ctl_elem_info_set_numid(elemInfo, ctlNumid);
+    snd_ctl_elem_info_set_interface(elemInfo, SND_CTL_ELEM_IFACE_MIXER);
+
+    // If control exist try to reuse it
+    err = snd_ctl_elem_info(ctlDev, elemInfo);
+    if (err) {
+        shouldCreate = 1;
+    } else {
+        int count, min, max, sndDev, subDev;
+        snd_ctl_elem_type_t type;
+
+        // ctl exit let's get associated elemID
+        snd_ctl_elem_id_alloca(&elemId);
+        snd_ctl_elem_info_get_id(elemInfo, elemId);
+
+        // If this is a hardware ctl only update value
+        if (ctlNumid != CTL_AUTO) {
+            json_object_object_get_ex(ctlJ, "val", &tmpJ);
+            ctlValue = json_object_get_int(tmpJ);
+            goto UpdateDefaultVal;
+        }
+
+        count = snd_ctl_elem_info_get_count(elemInfo);
+        min = (int) snd_ctl_elem_info_get_min(elemInfo);
+        max = (int) snd_ctl_elem_info_get_max(elemInfo);
+        type = snd_ctl_elem_info_get_type(elemInfo);
+        sndDev = (int) snd_ctl_elem_info_get_device(elemInfo);
+        subDev = (int) snd_ctl_elem_info_get_subdevice(elemInfo);
+
+        if (count == ctlCount && min == ctlMin && max == ctlMax && type == ctlType && sndDev == ctlSndDev && subDev == ctlSubDev) {
+            // Adjust value to best fit request
+            shouldCreate = 0;
+        } else {
+            err = snd_ctl_elem_remove(ctlDev, elemId);
+            shouldCreate = 1;
+            if (err < 0) {
+                AFB_ERROR("addOneSndCtl: ctlName=%s numid=%d fail to reset", snd_ctl_elem_info_get_name(elemInfo), snd_ctl_elem_info_get_numid(elemInfo));
+                goto DoNotUpdate;
+            };
+
+            // Control was deleted need to refresh elemInfo
+            snd_ctl_elem_info_alloca(&elemInfo);
+            if (ctlName) snd_ctl_elem_info_set_name(elemInfo, ctlName);
+            snd_ctl_elem_info_set_interface(elemInfo, SND_CTL_ELEM_IFACE_MIXER);
+            snd_ctl_elem_info(ctlDev, elemInfo);
+        }
+    }
+
+    // Add requested ID into elemInfo
+    snd_ctl_elem_info_set_device(elemInfo, ctlSndDev);
+    snd_ctl_elem_info_set_subdevice(elemInfo, ctlSubDev);
+
+    switch (ctlType) {
+        case SND_CTL_ELEM_TYPE_BOOLEAN:
+            if (shouldCreate) {
+                err = snd_ctl_add_boolean_elem_set(ctlDev, elemInfo, 1, ctlCount);
+                if (err) {
+                    AFB_ERROR("AddOntSndCtl Boolean: devid='%s' name='%s' count=%d", snd_ctl_name(ctlDev), ctlName, ctlCount);
+                    afb_req_fail_f(request, "ctl-invalid-bool", "devid='%s' name='%s' count=%d", snd_ctl_name(ctlDev), ctlName, ctlCount);
+                    goto OnErrorExit;
+                }
+            }
+
+            // Create a dummy TLV
+            elemTlv = allocate_bool_fake_tlv();
+
+            break;
+
+        case SND_CTL_ELEM_TYPE_INTEGER:
+            if (shouldCreate) {
+                err = snd_ctl_add_integer_elem_set(ctlDev, elemInfo, 1, ctlCount, ctlMin, ctlMax, ctlStep);
+                if (err) {
+                    AFB_ERROR("AddOntSndCtl Integer: devid='%s' name='%s' count=%d min=%d max=%d step=%d", snd_ctl_name(ctlDev), ctlName, ctlCount, ctlMin, ctlMax, ctlStep);
+                    afb_req_fail_f(request, "ctl-invalid-bool", "devid='%s' name='%s' count=%d min=%d max=%d step=%d", snd_ctl_name(ctlDev), ctlName, ctlCount, ctlMin, ctlMax, ctlStep);
+                    goto OnErrorExit;
+                }
+            }
+
+            // Fulup needed to be tested with some dB expert !!!
+            json_object *dbscaleJ;
+            if (json_object_object_get_ex(ctlJ, "dbscale", &dbscaleJ)) {
+                int min, max;
+
+                if (json_object_get_type(dbscaleJ) != json_type_object) {
+                    afb_req_fail_f(request, "ctl-invalid-dbscale", "devid=%s crl=%s invalid json in integer control", snd_ctl_name(ctlDev), json_object_get_string(ctlJ));
+                    goto OnErrorExit;
+
+                    json_object_object_get_ex(ctlJ, "min", &tmpJ);
+                    min = json_object_get_int(tmpJ);
+                    if (min >= 0) {
+                        afb_req_fail_f(request, "ctl-invalid-dbscale", "devid=%s crl=%s min should be a negative number", snd_ctl_name(ctlDev), json_object_get_string(ctlJ));
+                        goto OnErrorExit;
+                    }
+
+                    // default value 0=mute
+                    json_object_object_get_ex(ctlJ, "max", &tmpJ);
+                    max = json_object_get_int(tmpJ);
+
+                    // default value 1dB
+                    json_object_object_get_ex(ctlJ, "step", &tmpJ);
+                    int step = json_object_get_int(tmpJ);
+                    if (step <= 0) step = 1;
+
+                    elemTlv = allocate_int_dbscale_tlv(min, max, step);
+
+                }
+            } else {
+                // provide a fake linear TLV
+                elemTlv = allocate_int_linear_tlv(ctlMin, ctlMax);
+            }
+            break;
+
+        case SND_CTL_ELEM_TYPE_ENUMERATED:
+
+            if (shouldCreate) {
+                json_object *enumsJ;
+                json_object_object_get_ex(ctlJ, "enums", &enumsJ);
+                if (json_object_get_type(enumsJ) != json_type_array) {
+                    afb_req_fail_f(request, "ctl-missing-enums", "devid=%s crl=%s mandatory enum=xxx missing in enumerated control", snd_ctl_name(ctlDev), json_object_get_string(ctlJ));
+                    goto OnErrorExit;
+                }
+
+                int length = json_object_array_length(enumsJ);
+                const char **enumlabels = malloc(length * sizeof (char*));
+
+                for (int jdx = 0; jdx < length; jdx++) {
+                    tmpJ = json_object_array_get_idx(enumsJ, jdx);
+                    enumlabels[jdx] = json_object_get_string(tmpJ);
+                }
+
+                err = snd_ctl_add_enumerated_elem_set(ctlDev, elemInfo, 1, ctlCount, length, enumlabels);
+                if (err) {
+                    afb_req_fail_f(request, "ctl-invalid-bool", "devid=%s crl=%s invalid enumerated control", snd_ctl_name(ctlDev), json_object_get_string(ctlJ));
+                    goto OnErrorExit;
+                }
+
+                // Fulup should be an empty container
+                elemTlv = allocate_bool_fake_tlv();
+            }
+            break;
+
+            // Long Term Waiting ToDoList
+        case SND_CTL_ELEM_TYPE_INTEGER64:
+        case SND_CTL_ELEM_TYPE_BYTES:
+        default:
+            afb_req_fail_f(request, "ctl-invalid-type", "crl=%s unsupported type type=%d numid=%d", json_object_get_string(ctlJ), ctlType, ctlNumid);
+            goto OnErrorExit;
+    }
+
+UpdateDefaultVal:
+
+    // Set Value to default
+    snd_ctl_elem_value_alloca(&elemValue);
+    for (int idx = 0; idx < snd_ctl_elem_info_get_count(elemInfo); idx++) {
+        snd_ctl_elem_value_set_integer(elemValue, idx, ctlValue);
+    }
+
+    // write default values in newly created control
+    snd_ctl_elem_id_alloca(&elemId);
+    snd_ctl_elem_info(ctlDev, elemInfo);
+    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_WARNING("addOneSndCtl: crl=%s numid=%d fail to write Values error=%s", json_object_get_string(ctlJ), snd_ctl_elem_info_get_numid(elemInfo), snd_strerror(err));
+        goto DoNotUpdate;
+    }
+
+    // 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_WARNING("addOneSndCtl: crl=%s numid=%d fail to write TLV error=%s", json_object_get_string(ctlJ), snd_ctl_elem_info_get_numid(elemInfo), snd_strerror(err));
+            goto DoNotUpdate;
+        }
+    }
+
+DoNotUpdate:
+    // return newly created as a JSON object
+    alsaGetSingleCtl(ctlDev, elemId, &ctlRequest, queryMode);
+    if (ctlRequest.used < 0) {
+        AFB_WARNING("addOneSndCtl: crl=%s numid=%d Fail to get value", json_object_get_string(ctlJ), snd_ctl_elem_info_get_numid(elemInfo));
+    }
+    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
+    queryModeE 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);
+            if (!ctlsValues) goto OnErrorExit;
+            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);
+                else goto OnErrorExit;
+            }
+            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;
+}