path: root/Alsa-Plugin/_Alsa-Hal-plugin/AlsaHalPlugCtl.c

/*
 * Copyright (C) 2016 "IoT.bzh"
 * Author 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.
 *
 * Testing:
 *  1) Copy generated plugin [libasound_module_pcm_afbhal.so] in alsa-lib/ dir visible from LD_LIBRARY_PATH (eg: /usr/lib64/alsa-lib)
 *  2) Create a ~/.asounrc file base on following template
 *      ctl.agl_hal {
 *      type  afbhal
 *      devid "hw:4"
 *      cblib "afbhal_cb_sample.so"
 *      ctls {
 *          # ctlLabel {numid integer name "Alsa Ctl Name"}
 *          MasterSwitch { numid 4 name "My_First_Control" }
 *          MasterVol    { numid 5 name "My_Second_Control" }
 *          CB_sample    { ctlcb @AfbHalSampleCB name "My_Sample_Callback"}
 *      }
 *      pcm.agl_hal {
 *          type copy     # Copy PCM
 *          slave "hw:4"  # Slave name
 *      }
 *
 *  }
 *  3) Test with
 *     - amixer -Dagl_hal controls # should list all your controls
 *     - amixer -Dagl_hal cget numid=1
 *     - amixer -Dagl_hal cset numid=1 '10,20'
 */


#include <stdio.h>
#include <sys/ioctl.h>
#include "AlsaHalPlug.h"
#include <dlfcn.h>

static snd_ctl_ext_key_t AfbHalElemFind(snd_ctl_ext_t *ext, const snd_ctl_elem_id_t *id) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;
    snd_ctl_ext_key_t key = NULL;

    int numid = snd_ctl_elem_id_get_numid(id);
    if (numid > 0) {
        if (numid > plughandle->ctlsCount) goto OnErrorExit;
        key = (snd_ctl_ext_key_t) numid - 1;
        goto SucessExit;
    }

    const char *ctlName = snd_ctl_elem_id_get_name(id);
    if (ctlName == NULL) goto OnErrorExit;

    for (int idx = 0; idx < plughandle->ctlsCount; idx++) {
        if (!strcmp(ctlName, plughandle->ctls[idx].ctlName)) {
            key = idx;
            goto SucessExit;
        }
    }

SucessExit:
    return key;

OnErrorExit:
    return -1;
}

static int AfbHalGetAttrib(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int *type, unsigned int *acc, unsigned int *count) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;
    snd_ctl_elem_info_t *elemInfo = plughandle->infos[key];
    snd_ctl_cb_t callback = plughandle->cbs[key];


    // search for equivalent NUMID in effective sound card
    if (elemInfo) {
        *type = snd_ctl_elem_info_get_type(elemInfo);
        *count = snd_ctl_elem_info_get_count(elemInfo);
        *acc = SND_CTL_EXT_ACCESS_READWRITE; // Future ToBeDone
        return 0;
    }

    if (callback) {
        snd_ctl_get_attrib_t item;

        int err = callback(plughandle, CTLCB_GET_ATTRIBUTE, key, &item);
        if (!err) {
            *type = item.type;
            *acc = item.acc;
            *count = item.count;
        }
        return err;
    }

    return -1;
}

static int AfbHalGetIntInfo(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *imin, long *imax, long *istep) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;
    snd_ctl_elem_info_t *elemInfo = plughandle->infos[key];
    snd_ctl_cb_t callback = plughandle->cbs[key];

    if (elemInfo) {

        // Should be normalised to make everything 0-100%
        *imin = (long) snd_ctl_elem_info_get_min(elemInfo);
        *imax = (long) snd_ctl_elem_info_get_min(elemInfo);
        *istep = (long) snd_ctl_elem_info_get_min(elemInfo);
        return 0;
    }

    if (callback) {
        snd_ctl_get_int_info_t item;

        int err = callback(plughandle, CTLCB_GET_INTEGER_INFO, key, &item);
        if (!err) {
            *imin = item.imin;
            *imax = item.imax;
            *istep = item.istep;
        }
        return err;
    }

    return -1;
}

static int AfbHalGetEnumInfo(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int *items) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;
    snd_ctl_elem_info_t *elemInfo = plughandle->infos[key];
    snd_ctl_cb_t callback = plughandle->cbs[key];

    if (elemInfo) *items = snd_ctl_elem_info_get_items(elemInfo);
    if (callback) callback(plughandle, CTLCB_GET_ENUMERATED_INFO, key, items);

    return 0;
}

static int AfbHalGetEnumName(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int item, char *name, size_t name_max_len) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;
    snd_ctl_elem_info_t *elemInfo = plughandle->infos[key];

    //name= snd_ctl_elem_info_get_item_name(elemInfo);
    return 0;
}

static int AfbHalReadInt(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *value) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;
    snd_ctl_elem_info_t *elemInfo = plughandle->infos[key];

    return 0;
}

static int AfbHalReadEnumerate(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int *items) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;

    return 0;
}

static int AfbHalWriteInt(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *value) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;

    return 0;
}

static int AfbHalWriteEnum(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int *items) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;

    return 0;
}

static int AfbHalEventRead(snd_ctl_ext_t *ext, snd_ctl_elem_id_t *id, unsigned int *event_mask) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;

    return -EAGAIN;
}

static int AfbHalElemList(snd_ctl_ext_t *ext, unsigned int offset, snd_ctl_elem_id_t *id) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;

    snd_ctl_elem_id_set_interface(id, SND_CTL_ELEM_IFACE_MIXER);
    snd_ctl_elem_id_set_name(id, plughandle->ctls[offset].ctlName);

    return 0;
}

static int AfbHalElemCount(snd_ctl_ext_t *ext) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;
    int count = plughandle->ctlsCount;
    return count;
}

static void AfbHalClose(snd_ctl_ext_t *ext) {
    snd_ctl_hal_t *plughandle = (snd_ctl_hal_t*) ext->private_data;
    int err;

    for (int idx = 0; idx < plughandle->ctlsCount; idx++) {
        if (plughandle->ctls[idx].ctlName) free((void*) plughandle->ctls[idx].ctlName);
    }

    err = snd_ctl_close(plughandle->ctlDev);
    if (err) SNDERR("Fail Close sndctl: devid=%s err=%s", plughandle->devid, snd_strerror(err));

    if (plughandle->devid) free(plughandle->devid);
    free(plughandle);
}

static snd_ctl_ext_callback_t afbHalCBs = {
    .close = AfbHalClose,
    .elem_count = AfbHalElemCount,
    .elem_list = AfbHalElemList,
    .find_elem = AfbHalElemFind,
    .get_attribute = AfbHalGetAttrib,
    .get_integer_info = AfbHalGetIntInfo,
    .get_enumerated_info = AfbHalGetEnumInfo,
    .get_enumerated_name = AfbHalGetEnumName,
    .read_integer = AfbHalReadInt,
    .read_enumerated = AfbHalReadEnumerate,
    .write_integer = AfbHalWriteInt,
    .write_enumerated = AfbHalWriteEnum,
    .read_event = AfbHalEventRead,
};

SND_CTL_PLUGIN_DEFINE_FUNC(afbhal) {

    snd_config_iterator_t it, next;
    snd_ctl_hal_t *plughandle;
    int err;
    snd_ctl_cb_t AfbHalInitCB;
    const char *libname;

    plughandle = calloc(1, sizeof (snd_ctl_hal_t));

    snd_config_for_each(it, next, conf) {
        snd_config_t *node = snd_config_iterator_entry(it);
        const char *id;

        // ignore comment en empty lines
        if (snd_config_get_id(node, &id) < 0) continue;
        if (strcmp(id, "comment") == 0 || strcmp(id, "type") == 0 || strcmp(id, "hint") == 0) continue;

        // devid should point onto a valid sound card
        if (strcmp(id, "devid") == 0) {
            const char *devid;
            if (snd_config_get_string(node, &devid) < 0) {
                SNDERR("Invalid string type for %s", id);
                return -EINVAL;
            }
            plughandle->devid = strdup(devid);

            // open control interface for devid
            err = snd_ctl_open(&plughandle->ctlDev, plughandle->devid, 0);
            if (err < 0) {
                SNDERR("Fail to open control device for devid=%s", plughandle->devid);
                return -EINVAL;
            }
            continue;
        }

        if (strcmp(id, "cblib") == 0) {
            if (snd_config_get_string(node, &libname) < 0) {
                SNDERR("Invalid libname string for %s", id);
                return -EINVAL;
            }

            plughandle->dlHandle = dlopen(libname, RTLD_NOW);
            if (!plughandle->dlHandle) {
                SNDERR("Fail to open callback sharelib=%s error=%s", libname, dlerror());
                return -EINVAL;
            }

            AfbHalInitCB = dlsym(plughandle->dlHandle, "AfbHalInitCB");
            if (!AfbHalInitCB) {
                SNDERR("Fail find 'AfbHalInitCB' symbol into callbacks sharelib=%s", libname);
                return -EINVAL;
            }

            err = (*AfbHalInitCB)(plughandle, CTLCB_INIT, 0, 0);
            if (err) {
                SNDERR("Fail AfbHalInitCB err=%d", err);
                return -EINVAL;
            }

            continue;
        }

        if (strcmp(id, "ctl") == 0) {
            const char *ctlConf;
            snd_config_type_t ctype;
            snd_config_iterator_t currentCtl, follow;
            snd_config_t *itemConf;

            ctype = snd_config_get_type(node);
            if (ctype != SND_CONFIG_TYPE_COMPOUND) {
                snd_config_get_string(node, &ctlConf);
                SNDERR("Invalid compound type for %s", node);
                return -EINVAL;
            }

            // loop on each ctl within ctls

            snd_config_for_each(currentCtl, follow, node) {
                snd_config_t *ctlconfig = snd_config_iterator_entry(currentCtl);
                snd_ctl_elem_info_t *elemInfo;
                const char *ctlLabel, *ctlName;

                // ignore empty line
                if (snd_config_get_id(ctlconfig, &ctlLabel) < 0) continue;

                // each clt should be a valid config compound
                ctype = snd_config_get_type(ctlconfig);
                if (ctype != SND_CONFIG_TYPE_COMPOUND) {
                    snd_config_get_string(node, &ctlConf);
                    SNDERR("Invalid ctl config for %s", ctlLabel);
                    return -EINVAL;
                }

                err = snd_config_search(ctlconfig, "ctl", &itemConf);
                if (!err) {
                    if (snd_config_get_integer(itemConf, (long*) &plughandle->ctls[plughandle->ctlsCount].ctlNumid) < 0) {
                        SNDERR("Not Integer: ctl:%s numid should be a valid integer", ctlLabel);
                        return -EINVAL;
                    }

                    // Make sure than numid is valid on slave snd card
                    snd_ctl_elem_info_malloc(&elemInfo);
                    snd_ctl_elem_info_set_numid(elemInfo, (int) plughandle->ctls[plughandle->ctlsCount].ctlNumid);
                    plughandle->infos[plughandle->ctlsCount] = elemInfo;

                    err = snd_ctl_elem_info(plughandle->ctlDev, elemInfo);
                    if (err) {
                        SNDERR("Not Found: 'numid=%d' for 'devid=%s'", plughandle->ctls[plughandle->ctlsCount].ctlNumid, plughandle->devid);
                        return -EINVAL;
                    }
                }

                err = snd_config_search(ctlconfig, "ctlcb", &itemConf);
                if (!err) {
                    const char *funcname;
                    void *funcaddr;

                    if (snd_config_get_string(itemConf, &funcname) < 0) {
                        SNDERR("Not string: ctl:%s cbname should be a valid string", ctlLabel);
                        return -EINVAL;
                    }

                    if (funcname[0] != '@') {
                        SNDERR("Not string: ctl:%s cbname=%s should be prefixed with '@' ", ctlLabel, funcname);
                        return -EINVAL;
                    }

                    if (!plughandle->dlHandle) {
                        SNDERR("No CB: ctl:%s cblib:/my/libcallback missing from asoundrc", ctlLabel);
                        return -EINVAL;
                    }

                    funcaddr = dlsym(plughandle->dlHandle, &funcname[1]);
                    if (!funcaddr) {
                        SNDERR("NotFound CB: ctl:%s cbname='%s' no symbol into %s", ctlLabel, &funcname[1], libname);
                        return -EINVAL;
                    }
                    plughandle->cbs[plughandle->ctlsCount] = funcaddr;
                }

                err = snd_config_search(ctlconfig, "name", &itemConf);
                if (err) {
                    SNDERR("Not Found: 'name' mandatory in ctl config");
                    return -EINVAL;
                }

                if (snd_config_get_string(itemConf, &ctlName) < 0) {
                    SNDERR("Not String: ctl:%s 'name' should be a valie string", ctlLabel);
                    return -EINVAL;
                }
                plughandle->ctls[plughandle->ctlsCount].ctlName = strdup(ctlName);

                // move to next ctl if any
                plughandle->ctlsCount++;
            } // end for each ctl
            continue;
        }
        SNDERR("Unknown field %s", id);
        return -EINVAL;
    }



    // Create ALSA control plugin structure
    plughandle->ext.version = SND_CTL_EXT_VERSION;
    plughandle->ext.card_idx = 0; /* FIXME */
    strcpy(plughandle->ext.id, "AFB-HAL-CTL");
    strcpy(plughandle->ext.driver, "AFB-HAL");
    strcpy(plughandle->ext.name, "AFB-HAL Control Plugin");
    strcpy(plughandle->ext.mixername, "AFB-HAL Mixer Plugin");
    strcpy(plughandle->ext.longname, "Automotive-Linux Sound Abstraction Control Plugin");
    plughandle->ext.poll_fd = -1;
    plughandle->ext.callback = &afbHalCBs;
    plughandle->ext.private_data = (void*) plughandle;



    err = snd_ctl_ext_create(&plughandle->ext, name, mode);
    if (err < 0) {
        SNDERR("Fail Register sndctl for devid=%s", plughandle->devid);
        goto OnErrorExit;
    }

    // Plugin register controls update handlep before exiting
    *handlep = plughandle->ext.handle;
    return 0;

OnErrorExit:
    free(plughandle);
    return -1;
}

SND_CTL_PLUGIN_SYMBOL(afbhal);