/*
 * Author       Andreas Eversberg (jolly@eversberg.eu)
 * Based on source code structure by
 *              Karsten Keil (keil@isdn4linux.de)
 *
 *              This file is (c) under GNU PUBLIC LICENSE
 *
 * Thanks to    Karsten Keil (great drivers)
 *              Cologne Chip (great chips)
 *
 * This module does:
 *              Real-time tone generation
 *              DTMF detection
 *              Real-time cross-connection and conferrence
 *              Compensate jitter due to system load and hardware fault.
 *              All features are done in kernel space and will be realized
 *              using hardware, if available and supported by chip set.
 *              Blowfish encryption/decryption
 */

/* STRUCTURE:
 *
 * The dsp module provides layer 2 for b-channels (64kbit). It provides
 * transparent audio forwarding with special digital signal processing:
 *
 * - (1) generation of tones
 * - (2) detection of dtmf tones
 * - (3) crossconnecting and conferences (clocking)
 * - (4) echo generation for delay test
 * - (5) volume control
 * - (6) disable receive data
 * - (7) pipeline
 * - (8) encryption/decryption
 *
 * Look:
 *             TX            RX
 *         ------upper layer------
 *             |             ^
 *             |             |(6)
 *             v             |
 *       +-----+-------------+-----+
 *       |(3)(4)                   |
 *       |           CMX           |
 *       |                         |
 *       |           +-------------+
 *       |           |       ^
 *       |           |       |
 *       |+---------+|  +----+----+
 *       ||(1)      ||  |(2)      |
 *       ||         ||  |         |
 *       ||  Tones  ||  |  DTMF   |
 *       ||         ||  |         |
 *       ||         ||  |         |
 *       |+----+----+|  +----+----+
 *       +-----+-----+       ^
 *             |             |
 *             v             |
 *        +----+----+   +----+----+
 *        |(5)      |   |(5)      |
 *        |         |   |         |
 *        |TX Volume|   |RX Volume|
 *        |         |   |         |
 *        |         |   |         |
 *        +----+----+   +----+----+
 *             |             ^
 *             |             |
 *             v             |
 *        +----+-------------+----+
 *        |(7)                    |
 *        |                       |
 *        |  Pipeline Processing  |
 *        |                       |
 *        |                       |
 *        +----+-------------+----+
 *             |             ^
 *             |             |
 *             v             |
 *        +----+----+   +----+----+
 *        |(8)      |   |(8)      |
 *        |         |   |         |
 *        | Encrypt |   | Decrypt |
 *        |         |   |         |
 *        |         |   |         |
 *        +----+----+   +----+----+
 *             |             ^
 *             |             |
 *             v             |
 *         ------card  layer------
 *             TX            RX
 *
 * Above you can see the logical data flow. If software is used to do the
 * process, it is actually the real data flow. If hardware is used, data
 * may not flow, but hardware commands to the card, to provide the data flow
 * as shown.
 *
 * NOTE: The channel must be activated in order to make dsp work, even if
 * no data flow to the upper layer is intended. Activation can be done
 * after and before controlling the setting using PH_CONTROL requests.
 *
 * DTMF: Will be detected by hardware if possible. It is done before CMX
 * processing.
 *
 * Tones: Will be generated via software if endless looped audio fifos are
 * not supported by hardware. Tones will override all data from CMX.
 * It is not required to join a conference to use tones at any time.
 *
 * CMX: Is transparent when not used. When it is used, it will do
 * crossconnections and conferences via software if not possible through
 * hardware. If hardware capability is available, hardware is used.
 *
 * Echo: Is generated by CMX and is used to check performance of hard and
 * software CMX.
 *
 * The CMX has special functions for conferences with one, two and more
 * members. It will allow different types of data flow. Receive and transmit
 * data to/form upper layer may be switched on/off individually without losing
 * features of CMX, Tones and DTMF.
 *
 * Echo Cancellation: Sometimes we like to cancel echo from the interface.
 * Note that a VoIP call may not have echo caused by the IP phone. The echo
 * is generated by the telephone line connected to it. Because the delay
 * is high, it becomes an echo. RESULT: Echo Cachelation is required if
 * both echo AND delay is applied to an interface.
 * Remember that software CMX always generates a more or less delay.
 *
 * If all used features can be realized in hardware, and if transmit and/or
 * receive data ist disabled, the card may not send/receive any data at all.
 * Not receiving is useful if only announcements are played. Not sending is
 * useful if an answering machine records audio. Not sending and receiving is
 * useful during most states of the call. If supported by hardware, tones
 * will be played without cpu load. Small PBXs and NT-Mode applications will
 * not need expensive hardware when processing calls.
 *
 *
 * LOCKING:
 *
 * When data is received from upper or lower layer (card), the complete dsp
 * module is locked by a global lock.  This lock MUST lock irq, because it
 * must lock timer events by DSP poll timer.
 * When data is ready to be transmitted down, the data is queued and sent
 * outside lock and timer event.
 * PH_CONTROL must not change any settings, join or split conference members
 * during process of data.
 *
 * HDLC:
 *
 * It works quite the same as transparent, except that HDLC data is forwarded
 * to all other conference members if no hardware bridging is possible.
 * Send data will be writte to sendq. Sendq will be sent if confirm is received.
 * Conference cannot join, if one member is not hdlc.
 *
 */

#include <linux/delay.h>
#include <linux/gfp.h>
#include <linux/mISDNif.h>
#include <linux/mISDNdsp.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include "core.h"
#include "dsp.h"

static const char *mISDN_dsp_revision = "2.0";

static int debug;
static int options;
static int poll;
static int dtmfthreshold = 100;

MODULE_AUTHOR("Andreas Eversberg");
module_param(debug, uint, S_IRUGO | S_IWUSR);
module_param(options, uint, S_IRUGO | S_IWUSR);
module_param(poll, uint, S_IRUGO | S_IWUSR);
module_param(dtmfthreshold, uint, S_IRUGO | S_IWUSR);
MODULE_DESCRIPTION("mISDN driver for Digital Audio Processing of transparent data");
MODULE_LICENSE("GPL");

/*int spinnest = 0;*/

DEFINE_SPINLOCK(dsp_lock); /* global dsp lock */
LIST_HEAD(dsp_ilist);
LIST_HEAD(conf_ilist);
int dsp_debug;
int dsp_options;
int dsp_poll, dsp_tics;

/* check if rx may be turned off or must be turned on */
static void
dsp_rx_off_member(struct dsp *dsp)
{
        struct mISDN_ctrl_req   cq;
        int rx_off = 1;

        memset(&cq, 0, sizeof(cq));

        if (!dsp->features_rx_off)
                return;

        /* not disabled */
        if (!dsp->rx_disabled)
                rx_off = 0;
        /* software dtmf */
        else if (dsp->dtmf.software)
                rx_off = 0;
        /* echo in software */
        else if (dsp->echo.software)
                rx_off = 0;
        /* bridge in software */
        else if (dsp->conf && dsp->conf->software)
                rx_off = 0;
        /* data is not required by user space and not required
         * for echo dtmf detection, soft-echo, soft-bridging */

        if (rx_off == dsp->rx_is_off)
                return;

        if (!dsp->ch.peer) {
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: no peer, no rx_off\n",
                               __func__);
                return;
        }
        cq.op = MISDN_CTRL_RX_OFF;
        cq.p1 = rx_off;
        if (dsp->ch.peer->ctrl(dsp->ch.peer, CONTROL_CHANNEL, &cq)) {
                printk(KERN_DEBUG "%s: 2nd CONTROL_CHANNEL failed\n",
                       __func__);
                return;
        }
        dsp->rx_is_off = rx_off;
        if (dsp_debug & DEBUG_DSP_CORE)
                printk(KERN_DEBUG "%s: %s set rx_off = %d\n",
                       __func__, dsp->name, rx_off);
}
static void
dsp_rx_off(struct dsp *dsp)
{
        struct dsp_conf_member  *member;

        if (dsp_options & DSP_OPT_NOHARDWARE)
                return;

        /* no conf */
        if (!dsp->conf) {
                dsp_rx_off_member(dsp);
                return;
        }
        /* check all members in conf */
        list_for_each_entry(member, &dsp->conf->mlist, list) {
                dsp_rx_off_member(member->dsp);
        }
}

/* enable "fill empty" feature */
static void
dsp_fill_empty(struct dsp *dsp)
{
        struct mISDN_ctrl_req   cq;

        memset(&cq, 0, sizeof(cq));

        if (!dsp->ch.peer) {
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: no peer, no fill_empty\n",
                               __func__);
                return;
        }
        cq.op = MISDN_CTRL_FILL_EMPTY;
        cq.p1 = 1;
        cq.p2 = dsp_silence;
        if (dsp->ch.peer->ctrl(dsp->ch.peer, CONTROL_CHANNEL, &cq)) {
                printk(KERN_DEBUG "%s: CONTROL_CHANNEL failed\n",
                       __func__);
                return;
        }
        if (dsp_debug & DEBUG_DSP_CORE)
                printk(KERN_DEBUG "%s: %s set fill_empty = 1\n",
                       __func__, dsp->name);
}

static int
dsp_control_req(struct dsp *dsp, struct mISDNhead *hh, struct sk_buff *skb)
{
        struct sk_buff  *nskb;
        int ret = 0;
        int cont;
        u8 *data;
        int len;

        if (skb->len < sizeof(int)) {
                printk(KERN_ERR "%s: PH_CONTROL message too short\n", __func__);
                return -EINVAL;
        }
        cont = *((int *)skb->data);
        len = skb->len - sizeof(int);
        data = skb->data + sizeof(int);

        switch (cont) {
        case DTMF_TONE_START: /* turn on DTMF */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: start dtmf\n", __func__);
                if (len == sizeof(int)) {
                        if (dsp_debug & DEBUG_DSP_CORE)
                                printk(KERN_NOTICE "changing DTMF Threshold "
                                       "to %d\n", *((int *)data));
                        dsp->dtmf.treshold = (*(int *)data) * 10000;
                }
                dsp->dtmf.enable = 1;
                /* init goertzel */
                dsp_dtmf_goertzel_init(dsp);

                /* check dtmf hardware */
                dsp_dtmf_hardware(dsp);
                dsp_rx_off(dsp);
                break;
        case DTMF_TONE_STOP: /* turn off DTMF */
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: stop dtmf\n", __func__);
                dsp->dtmf.enable = 0;
                dsp->dtmf.hardware = 0;
                dsp->dtmf.software = 0;
                break;
        case DSP_CONF_JOIN: /* join / update conference */
                if (len < sizeof(int)) {
                        ret = -EINVAL;
                        break;
                }
                if (*((u32 *)data) == 0)
                        goto conf_split;
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: join conference %d\n",
                               __func__, *((u32 *)data));
                ret = dsp_cmx_conf(dsp, *((u32 *)data));
                /* dsp_cmx_hardware will also be called here */
                dsp_rx_off(dsp);
                if (dsp_debug & DEBUG_DSP_CMX)
                        dsp_cmx_debug(dsp);
                break;
        case DSP_CONF_SPLIT: /* remove from conference */
        conf_split:
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: release conference\n", __func__);
                ret = dsp_cmx_conf(dsp, 0);
                /* dsp_cmx_hardware will also be called here */
                if (dsp_debug & DEBUG_DSP_CMX)
                        dsp_cmx_debug(dsp);
                dsp_rx_off(dsp);
                break;
        case DSP_TONE_PATT_ON: /* play tone */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (len < sizeof(int)) {
                        ret = -EINVAL;
                        break;
                }
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: turn tone 0x%x on\n",
                               __func__, *((int *)skb->data));
                ret = dsp_tone(dsp, *((int *)data));
                if (!ret) {
                        dsp_cmx_hardware(dsp->conf, dsp);
                        dsp_rx_off(dsp);
                }
                if (!dsp->tone.tone)
                        goto tone_off;
                break;
        case DSP_TONE_PATT_OFF: /* stop tone */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: turn tone off\n", __func__);
                dsp_tone(dsp, 0);
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_rx_off(dsp);
                /* reset tx buffers (user space data) */
        tone_off:
                dsp->rx_W = 0;
                dsp->rx_R = 0;
                break;
        case DSP_VOL_CHANGE_TX: /* change volume */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (len < sizeof(int)) {
                        ret = -EINVAL;
                        break;
                }
                dsp->tx_volume = *((int *)data);
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: change tx vol to %d\n",
                               __func__, dsp->tx_volume);
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_dtmf_hardware(dsp);
                dsp_rx_off(dsp);
                break;
        case DSP_VOL_CHANGE_RX: /* change volume */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (len < sizeof(int)) {
                        ret = -EINVAL;
                        break;
                }
                dsp->rx_volume = *((int *)data);
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: change rx vol to %d\n",
                               __func__, dsp->tx_volume);
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_dtmf_hardware(dsp);
                dsp_rx_off(dsp);
                break;
        case DSP_ECHO_ON: /* enable echo */
                dsp->echo.software = 1; /* soft echo */
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: enable cmx-echo\n", __func__);
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_rx_off(dsp);
                if (dsp_debug & DEBUG_DSP_CMX)
                        dsp_cmx_debug(dsp);
                break;
        case DSP_ECHO_OFF: /* disable echo */
                dsp->echo.software = 0;
                dsp->echo.hardware = 0;
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: disable cmx-echo\n", __func__);
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_rx_off(dsp);
                if (dsp_debug & DEBUG_DSP_CMX)
                        dsp_cmx_debug(dsp);
                break;
        case DSP_RECEIVE_ON: /* enable receive to user space */
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: enable receive to user "
                               "space\n", __func__);
                dsp->rx_disabled = 0;
                dsp_rx_off(dsp);
                break;
        case DSP_RECEIVE_OFF: /* disable receive to user space */
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: disable receive to "
                               "user space\n", __func__);
                dsp->rx_disabled = 1;
                dsp_rx_off(dsp);
                break;
        case DSP_MIX_ON: /* enable mixing of tx data */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: enable mixing of "
                               "tx-data with conf members\n", __func__);
                dsp->tx_mix = 1;
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_rx_off(dsp);
                if (dsp_debug & DEBUG_DSP_CMX)
                        dsp_cmx_debug(dsp);
                break;
        case DSP_MIX_OFF: /* disable mixing of tx data */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: disable mixing of "
                               "tx-data with conf members\n", __func__);
                dsp->tx_mix = 0;
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_rx_off(dsp);
                if (dsp_debug & DEBUG_DSP_CMX)
                        dsp_cmx_debug(dsp);
                break;
        case DSP_TXDATA_ON: /* enable txdata */
                dsp->tx_data = 1;
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: enable tx-data\n", __func__);
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_rx_off(dsp);
                if (dsp_debug & DEBUG_DSP_CMX)
                        dsp_cmx_debug(dsp);
                break;
        case DSP_TXDATA_OFF: /* disable txdata */
                dsp->tx_data = 0;
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: disable tx-data\n", __func__);
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_rx_off(dsp);
                if (dsp_debug & DEBUG_DSP_CMX)
                        dsp_cmx_debug(dsp);
                break;
        case DSP_DELAY: /* use delay algorithm instead of dynamic
                           jitter algorithm */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (len < sizeof(int)) {
                        ret = -EINVAL;
                        break;
                }
                dsp->cmx_delay = (*((int *)data)) << 3;
                /* milliseconds to samples */
                if (dsp->cmx_delay >= (CMX_BUFF_HALF >> 1))
                        /* clip to half of maximum usable buffer
                           (half of half buffer) */
                        dsp->cmx_delay = (CMX_BUFF_HALF >> 1) - 1;
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: use delay algorithm to "
                               "compensate jitter (%d samples)\n",
                               __func__, dsp->cmx_delay);
                break;
        case DSP_JITTER: /* use dynamic jitter algorithm instead of
                            delay algorithm */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                dsp->cmx_delay = 0;
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: use jitter algorithm to "
                               "compensate jitter\n", __func__);
                break;
        case DSP_TX_DEJITTER: /* use dynamic jitter algorithm for tx-buffer */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                dsp->tx_dejitter = 1;
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: use dejitter on TX "
                               "buffer\n", __func__);
                break;
        case DSP_TX_DEJ_OFF: /* use tx-buffer without dejittering*/
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                dsp->tx_dejitter = 0;
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: use TX buffer without "
                               "dejittering\n", __func__);
                break;
        case DSP_PIPELINE_CFG:
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (len > 0 && ((char *)data)[len - 1]) {
                        printk(KERN_DEBUG "%s: pipeline config string "
                               "is not NULL terminated!\n", __func__);
                        ret = -EINVAL;
                } else {
                        dsp->pipeline.inuse = 1;
                        dsp_cmx_hardware(dsp->conf, dsp);
                        ret = dsp_pipeline_build(&dsp->pipeline,
                                                 len > 0 ? data : NULL);
                        dsp_cmx_hardware(dsp->conf, dsp);
                        dsp_rx_off(dsp);
                }
                break;
        case DSP_BF_ENABLE_KEY: /* turn blowfish on */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (len < 4 || len > 56) {
                        ret = -EINVAL;
                        break;
                }
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: turn blowfish on (key "
                               "not shown)\n", __func__);
                ret = dsp_bf_init(dsp, (u8 *)data, len);
                /* set new cont */
                if (!ret)
                        cont = DSP_BF_ACCEPT;
                else
                        cont = DSP_BF_REJECT;
                /* send indication if it worked to set it */
                nskb = _alloc_mISDN_skb(PH_CONTROL_IND, MISDN_ID_ANY,
                                        sizeof(int), &cont, GFP_ATOMIC);
                if (nskb) {
                        if (dsp->up) {
                                if (dsp->up->send(dsp->up, nskb))
                                        dev_kfree_skb(nskb);
                        } else
                                dev_kfree_skb(nskb);
                }
                if (!ret) {
                        dsp_cmx_hardware(dsp->conf, dsp);
                        dsp_dtmf_hardware(dsp);
                        dsp_rx_off(dsp);
                }
                break;
        case DSP_BF_DISABLE: /* turn blowfish off */
                if (dsp->hdlc) {
                        ret = -EINVAL;
                        break;
                }
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: turn blowfish off\n", __func__);
                dsp_bf_cleanup(dsp);
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_dtmf_hardware(dsp);
                dsp_rx_off(dsp);
                break;
        default:
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: ctrl req %x unhandled\n",
                               __func__, cont);
                ret = -EINVAL;
        }
        return ret;
}

static void
get_features(struct mISDNchannel *ch)
{
        struct dsp              *dsp = container_of(ch, struct dsp, ch);
        struct mISDN_ctrl_req   cq;

        if (!ch->peer) {
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: no peer, no features\n",
                               __func__);
                return;
        }
        memset(&cq, 0, sizeof(cq));
        cq.op = MISDN_CTRL_GETOP;
        if (ch->peer->ctrl(ch->peer, CONTROL_CHANNEL, &cq) < 0) {
                printk(KERN_DEBUG "%s: CONTROL_CHANNEL failed\n",
                       __func__);
                return;
        }
        if (cq.op & MISDN_CTRL_RX_OFF)
                dsp->features_rx_off = 1;
        if (cq.op & MISDN_CTRL_FILL_EMPTY)
                dsp->features_fill_empty = 1;
        if (dsp_options & DSP_OPT_NOHARDWARE)
                return;
        if ((cq.op & MISDN_CTRL_HW_FEATURES_OP)) {
                cq.op = MISDN_CTRL_HW_FEATURES;
                *((u_long *)&cq.p1) = (u_long)&dsp->features;
                if (ch->peer->ctrl(ch->peer, CONTROL_CHANNEL, &cq)) {
                        printk(KERN_DEBUG "%s: 2nd CONTROL_CHANNEL failed\n",
                               __func__);
                }
        } else
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: features not supported for %s\n",
                               __func__, dsp->name);
}

static int
dsp_function(struct mISDNchannel *ch,  struct sk_buff *skb)
{
        struct dsp              *dsp = container_of(ch, struct dsp, ch);
        struct mISDNhead        *hh;
        int                     ret = 0;
        u8                      *digits = NULL;
        u_long                  flags;

        hh = mISDN_HEAD_P(skb);
        switch (hh->prim) {
                /* FROM DOWN */
        case (PH_DATA_CNF):
                dsp->data_pending = 0;
                /* trigger next hdlc frame, if any */
                if (dsp->hdlc) {
                        spin_lock_irqsave(&dsp_lock, flags);
                        if (dsp->b_active)
                                schedule_work(&dsp->workq);
                        spin_unlock_irqrestore(&dsp_lock, flags);
                }
                break;
        case (PH_DATA_IND):
        case (DL_DATA_IND):
                if (skb->len < 1) {
                        ret = -EINVAL;
                        break;
                }
                if (dsp->rx_is_off) {
                        if (dsp_debug & DEBUG_DSP_CORE)
                                printk(KERN_DEBUG "%s: rx-data during rx_off"
                                       " for %s\n",
                                       __func__, dsp->name);
                }
                if (dsp->hdlc) {
                        /* hdlc */
                        spin_lock_irqsave(&dsp_lock, flags);
                        dsp_cmx_hdlc(dsp, skb);
                        spin_unlock_irqrestore(&dsp_lock, flags);
                        if (dsp->rx_disabled) {
                                /* if receive is not allowed */
                                break;
                        }
                        hh->prim = DL_DATA_IND;
                        if (dsp->up)
                                return dsp->up->send(dsp->up, skb);
                        break;
                }

                spin_lock_irqsave(&dsp_lock, flags);

                /* decrypt if enabled */
                if (dsp->bf_enable)
                        dsp_bf_decrypt(dsp, skb->data, skb->len);
                /* pipeline */
                if (dsp->pipeline.inuse)
                        dsp_pipeline_process_rx(&dsp->pipeline, skb->data,
                                                skb->len, hh->id);
                /* change volume if requested */
                if (dsp->rx_volume)
                        dsp_change_volume(skb, dsp->rx_volume);
                /* check if dtmf soft decoding is turned on */
                if (dsp->dtmf.software) {
                        digits = dsp_dtmf_goertzel_decode(dsp, skb->data,
                                                          skb->len, (dsp_options & DSP_OPT_ULAW) ? 1 : 0);
                }
                /* we need to process receive data if software */
                if (dsp->conf && dsp->conf->software) {
                        /* process data from card at cmx */
                        dsp_cmx_receive(dsp, skb);
                }

                spin_unlock_irqrestore(&dsp_lock, flags);

                /* send dtmf result, if any */
                if (digits) {
                        while (*digits) {
                                int k;
                                struct sk_buff *nskb;
                                if (dsp_debug & DEBUG_DSP_DTMF)
                                        printk(KERN_DEBUG "%s: digit"
                                               "(%c) to layer %s\n",
                                               __func__, *digits, dsp->name);
                                k = *digits | DTMF_TONE_VAL;
                                nskb = _alloc_mISDN_skb(PH_CONTROL_IND,
                                                        MISDN_ID_ANY, sizeof(int), &k,
                                                        GFP_ATOMIC);
                                if (nskb) {
                                        if (dsp->up) {
                                                if (dsp->up->send(
                                                            dsp->up, nskb))
                                                        dev_kfree_skb(nskb);
                                        } else
                                                dev_kfree_skb(nskb);
                                }
                                digits++;
                        }
                }
                if (dsp->rx_disabled) {
                        /* if receive is not allowed */
                        break;
                }
                hh->prim = DL_DATA_IND;
                if (dsp->up)
                        return dsp->up->send(dsp->up, skb);
                break;
        case (PH_CONTROL_IND):
                if (dsp_debug & DEBUG_DSP_DTMFCOEFF)
                        printk(KERN_DEBUG "%s: PH_CONTROL INDICATION "
                               "received: %x (len %d) %s\n", __func__,
                               hh->id, skb->len, dsp->name);
                switch (hh->id) {
                case (DTMF_HFC_COEF): /* getting coefficients */
                        if (!dsp->dtmf.hardware) {
                                if (dsp_debug & DEBUG_DSP_DTMFCOEFF)
                                        printk(KERN_DEBUG "%s: ignoring DTMF "
                                               "coefficients from HFC\n",
                                               __func__);
                                break;
                        }
                        digits = dsp_dtmf_goertzel_decode(dsp, skb->data,
                                                          skb->len, 2);
                        while (*digits) {
                                int k;
                                struct sk_buff *nskb;
                                if (dsp_debug & DEBUG_DSP_DTMF)
                                        printk(KERN_DEBUG "%s: digit"
                                               "(%c) to layer %s\n",
                                               __func__, *digits, dsp->name);
                                k = *digits | DTMF_TONE_VAL;
                                nskb = _alloc_mISDN_skb(PH_CONTROL_IND,
                                                        MISDN_ID_ANY, sizeof(int), &k,
                                                        GFP_ATOMIC);
                                if (nskb) {
                                        if (dsp->up) {
                                                if (dsp->up->send(
                                                            dsp->up, nskb))
                                                        dev_kfree_skb(nskb);
                                        } else
                                                dev_kfree_skb(nskb);
                                }
                                digits++;
                        }
                        break;
                case (HFC_VOL_CHANGE_TX): /* change volume */
                        if (skb->len != sizeof(int)) {
                                ret = -EINVAL;
                                break;
                        }
                        spin_lock_irqsave(&dsp_lock, flags);
                        dsp->tx_volume = *((int *)skb->data);
                        if (dsp_debug & DEBUG_DSP_CORE)
                                printk(KERN_DEBUG "%s: change tx volume to "
                                       "%d\n", __func__, dsp->tx_volume);
                        dsp_cmx_hardware(dsp->conf, dsp);
                        dsp_dtmf_hardware(dsp);
                        dsp_rx_off(dsp);
                        spin_unlock_irqrestore(&dsp_lock, flags);
                        break;
                default:
                        if (dsp_debug & DEBUG_DSP_CORE)
                                printk(KERN_DEBUG "%s: ctrl ind %x unhandled "
                                       "%s\n", __func__, hh->id, dsp->name);
                        ret = -EINVAL;
                }
                break;
        case (PH_ACTIVATE_IND):
        case (PH_ACTIVATE_CNF):
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: b_channel is now active %s\n",
                               __func__, dsp->name);
                /* bchannel now active */
                spin_lock_irqsave(&dsp_lock, flags);
                dsp->b_active = 1;
                dsp->data_pending = 0;
                dsp->rx_init = 1;
                /* rx_W and rx_R will be adjusted on first frame */
                dsp->rx_W = 0;
                dsp->rx_R = 0;
                memset(dsp->rx_buff, 0, sizeof(dsp->rx_buff));
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_dtmf_hardware(dsp);
                dsp_rx_off(dsp);
                spin_unlock_irqrestore(&dsp_lock, flags);
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: done with activation, sending "
                               "confirm to user space. %s\n", __func__,
                               dsp->name);
                /* send activation to upper layer */
                hh->prim = DL_ESTABLISH_CNF;
                if (dsp->up)
                        return dsp->up->send(dsp->up, skb);
                break;
        case (PH_DEACTIVATE_IND):
        case (PH_DEACTIVATE_CNF):
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: b_channel is now inactive %s\n",
                               __func__, dsp->name);
                /* bchannel now inactive */
                spin_lock_irqsave(&dsp_lock, flags);
                dsp->b_active = 0;
                dsp->data_pending = 0;
                dsp_cmx_hardware(dsp->conf, dsp);
                dsp_rx_off(dsp);
                spin_unlock_irqrestore(&dsp_lock, flags);
                hh->prim = DL_RELEASE_CNF;
                if (dsp->up)
                        return dsp->up->send(dsp->up, skb);
                break;
                /* FROM UP */
        case (DL_DATA_REQ):
        case (PH_DATA_REQ):
                if (skb->len < 1) {
                        ret = -EINVAL;
                        break;
                }
                if (dsp->hdlc) {
                        /* hdlc */
                        if (!dsp->b_active) {
                                ret = -EIO;
                                break;
                        }
                        hh->prim = PH_DATA_REQ;
                        spin_lock_irqsave(&dsp_lock, flags);
                        skb_queue_tail(&dsp->sendq, skb);
                        schedule_work(&dsp->workq);
                        spin_unlock_irqrestore(&dsp_lock, flags);
                        return 0;
                }
                /* send data to tx-buffer (if no tone is played) */
                if (!dsp->tone.tone) {
                        spin_lock_irqsave(&dsp_lock, flags);
                        dsp_cmx_transmit(dsp, skb);
                        spin_unlock_irqrestore(&dsp_lock, flags);
                }
                break;
        case (PH_CONTROL_REQ):
                spin_lock_irqsave(&dsp_lock, flags);
                ret = dsp_control_req(dsp, hh, skb);
                spin_unlock_irqrestore(&dsp_lock, flags);
                break;
        case (DL_ESTABLISH_REQ):
        case (PH_ACTIVATE_REQ):
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: activating b_channel %s\n",
                               __func__, dsp->name);
                if (dsp->dtmf.hardware || dsp->dtmf.software)
                        dsp_dtmf_goertzel_init(dsp);
                get_features(ch);
                /* enable fill_empty feature */
                if (dsp->features_fill_empty)
                        dsp_fill_empty(dsp);
                /* send ph_activate */
                hh->prim = PH_ACTIVATE_REQ;
                if (ch->peer)
                        return ch->recv(ch->peer, skb);
                break;
        case (DL_RELEASE_REQ):
        case (PH_DEACTIVATE_REQ):
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: releasing b_channel %s\n",
                               __func__, dsp->name);
                spin_lock_irqsave(&dsp_lock, flags);
                dsp->tone.tone = 0;
                dsp->tone.hardware = 0;
                dsp->tone.software = 0;
                if (timer_pending(&dsp->tone.tl))
                        timer_delete(&dsp->tone.tl);
                if (dsp->conf)
                        dsp_cmx_conf(dsp, 0); /* dsp_cmx_hardware will also be
                                                 called here */
                skb_queue_purge(&dsp->sendq);
                spin_unlock_irqrestore(&dsp_lock, flags);
                hh->prim = PH_DEACTIVATE_REQ;
                if (ch->peer)
                        return ch->recv(ch->peer, skb);
                break;
        default:
                if (dsp_debug & DEBUG_DSP_CORE)
                        printk(KERN_DEBUG "%s: msg %x unhandled %s\n",
                               __func__, hh->prim, dsp->name);
                ret = -EINVAL;
        }
        if (!ret)
                dev_kfree_skb(skb);
        return ret;
}

static int
dsp_ctrl(struct mISDNchannel *ch, u_int cmd, void *arg)
{
        struct dsp              *dsp = container_of(ch, struct dsp, ch);
        u_long          flags;

        if (debug & DEBUG_DSP_CTRL)
                printk(KERN_DEBUG "%s:(%x)\n", __func__, cmd);

        switch (cmd) {
        case OPEN_CHANNEL:
                break;
        case CLOSE_CHANNEL:
                if (dsp->ch.peer)
                        dsp->ch.peer->ctrl(dsp->ch.peer, CLOSE_CHANNEL, NULL);

                /* wait until workqueue has finished,
                 * must lock here, or we may hit send-process currently
                 * queueing. */
                spin_lock_irqsave(&dsp_lock, flags);
                dsp->b_active = 0;
                spin_unlock_irqrestore(&dsp_lock, flags);
                /* MUST not be locked, because it waits until queue is done. */
                cancel_work_sync(&dsp->workq);
                spin_lock_irqsave(&dsp_lock, flags);
                if (timer_pending(&dsp->tone.tl))
                        timer_delete(&dsp->tone.tl);
                skb_queue_purge(&dsp->sendq);
                if (dsp_debug & DEBUG_DSP_CTRL)
                        printk(KERN_DEBUG "%s: releasing member %s\n",
                               __func__, dsp->name);
                dsp->b_active = 0;
                dsp_cmx_conf(dsp, 0); /* dsp_cmx_hardware will also be called
                                         here */
                dsp_pipeline_destroy(&dsp->pipeline);

                if (dsp_debug & DEBUG_DSP_CTRL)
                        printk(KERN_DEBUG "%s: remove & destroy object %s\n",
                               __func__, dsp->name);
                list_del(&dsp->list);
                spin_unlock_irqrestore(&dsp_lock, flags);

                if (dsp_debug & DEBUG_DSP_CTRL)
                        printk(KERN_DEBUG "%s: dsp instance released\n",
                               __func__);
                vfree(dsp);
                module_put(THIS_MODULE);
                break;
        }
        return 0;
}

static void
dsp_send_bh(struct work_struct *work)
{
        struct dsp *dsp = container_of(work, struct dsp, workq);
        struct sk_buff *skb;
        struct mISDNhead        *hh;

        if (dsp->hdlc && dsp->data_pending)
                return; /* wait until data has been acknowledged */

        /* send queued data */
        while ((skb = skb_dequeue(&dsp->sendq))) {
                /* in locked date, we must have still data in queue */
                if (dsp->data_pending) {
                        if (dsp_debug & DEBUG_DSP_CORE)
                                printk(KERN_DEBUG "%s: fifo full %s, this is "
                                       "no bug!\n", __func__, dsp->name);
                        /* flush transparent data, if not acked */
                        dev_kfree_skb(skb);
                        continue;
                }
                hh = mISDN_HEAD_P(skb);
                if (hh->prim == DL_DATA_REQ) {
                        /* send packet up */
                        if (dsp->up) {
                                if (dsp->up->send(dsp->up, skb))
                                        dev_kfree_skb(skb);
                        } else
                                dev_kfree_skb(skb);
                } else {
                        /* send packet down */
                        if (dsp->ch.peer) {
                                dsp->data_pending = 1;
                                if (dsp->ch.recv(dsp->ch.peer, skb)) {
                                        dev_kfree_skb(skb);
                                        dsp->data_pending = 0;
                                }
                        } else
                                dev_kfree_skb(skb);
                }
        }
}

static int
dspcreate(struct channel_req *crq)
{
        struct dsp              *ndsp;
        u_long          flags;

        if (crq->protocol != ISDN_P_B_L2DSP
            && crq->protocol != ISDN_P_B_L2DSPHDLC)
                return -EPROTONOSUPPORT;
        ndsp = vzalloc(sizeof(struct dsp));
        if (!ndsp) {
                printk(KERN_ERR "%s: vmalloc struct dsp failed\n", __func__);
                return -ENOMEM;
        }
        if (dsp_debug & DEBUG_DSP_CTRL)
                printk(KERN_DEBUG "%s: creating new dsp instance\n", __func__);

        /* default enabled */
        INIT_WORK(&ndsp->workq, (void *)dsp_send_bh);
        skb_queue_head_init(&ndsp->sendq);
        ndsp->ch.send = dsp_function;
        ndsp->ch.ctrl = dsp_ctrl;
        ndsp->up = crq->ch;
        crq->ch = &ndsp->ch;
        if (crq->protocol == ISDN_P_B_L2DSP) {
                crq->protocol = ISDN_P_B_RAW;
                ndsp->hdlc = 0;
        } else {
                crq->protocol = ISDN_P_B_HDLC;
                ndsp->hdlc = 1;
        }
        if (!try_module_get(THIS_MODULE))
                printk(KERN_WARNING "%s:cannot get module\n",
                       __func__);

        sprintf(ndsp->name, "DSP_C%x(0x%p)",
                ndsp->up->st->dev->id + 1, ndsp);
        /* set frame size to start */
        ndsp->features.hfc_id = -1; /* current PCM id */
        ndsp->features.pcm_id = -1; /* current PCM id */
        ndsp->pcm_slot_rx = -1; /* current CPM slot */
        ndsp->pcm_slot_tx = -1;
        ndsp->pcm_bank_rx = -1;
        ndsp->pcm_bank_tx = -1;
        ndsp->hfc_conf = -1; /* current conference number */
        /* set tone timer */
        timer_setup(&ndsp->tone.tl, dsp_tone_timeout, 0);

        if (dtmfthreshold < 20 || dtmfthreshold > 500)
                dtmfthreshold = 200;
        ndsp->dtmf.treshold = dtmfthreshold * 10000;

        /* init pipeline append to list */
        spin_lock_irqsave(&dsp_lock, flags);
        dsp_pipeline_init(&ndsp->pipeline);
        list_add_tail(&ndsp->list, &dsp_ilist);
        spin_unlock_irqrestore(&dsp_lock, flags);

        return 0;
}


static struct Bprotocol DSP = {
        .Bprotocols = (1 << (ISDN_P_B_L2DSP & ISDN_P_B_MASK))
        | (1 << (ISDN_P_B_L2DSPHDLC & ISDN_P_B_MASK)),
        .name = "dsp",
        .create = dspcreate
};

static int __init dsp_init(void)
{
        int err;
        int tics;

        printk(KERN_INFO "DSP module %s\n", mISDN_dsp_revision);

        dsp_options = options;
        dsp_debug = debug;

        /* set packet size */
        dsp_poll = poll;
        if (dsp_poll) {
                if (dsp_poll > MAX_POLL) {
                        printk(KERN_ERR "%s: Wrong poll value (%d), use %d "
                               "maximum.\n", __func__, poll, MAX_POLL);
                        err = -EINVAL;
                        return err;
                }
                if (dsp_poll < 8) {
                        printk(KERN_ERR "%s: Wrong poll value (%d), use 8 "
                               "minimum.\n", __func__, dsp_poll);
                        err = -EINVAL;
                        return err;
                }
                dsp_tics = poll * HZ / 8000;
                if (dsp_tics * 8000 != poll * HZ) {
                        printk(KERN_INFO "mISDN_dsp: Cannot clock every %d "
                               "samples (0,125 ms). It is not a multiple of "
                               "%d HZ.\n", poll, HZ);
                        err = -EINVAL;
                        return err;
                }
        } else {
                poll = 8;
                while (poll <= MAX_POLL) {
                        tics = (poll * HZ) / 8000;
                        if (tics * 8000 == poll * HZ) {
                                dsp_tics = tics;
                                dsp_poll = poll;
                                if (poll >= 64)
                                        break;
                        }
                        poll++;
                }
        }
        if (dsp_poll == 0) {
                printk(KERN_INFO "mISDN_dsp: There is no multiple of kernel "
                       "clock that equals exactly the duration of 8-256 "
                       "samples. (Choose kernel clock speed like 100, 250, "
                       "300, 1000)\n");
                err = -EINVAL;
                return err;
        }
        printk(KERN_INFO "mISDN_dsp: DSP clocks every %d samples. This equals "
               "%d jiffies.\n", dsp_poll, dsp_tics);

        /* init conversion tables */
        dsp_audio_generate_law_tables();
        dsp_silence = (dsp_options & DSP_OPT_ULAW) ? 0xff : 0x2a;
        dsp_audio_law_to_s32 = (dsp_options & DSP_OPT_ULAW) ?
                dsp_audio_ulaw_to_s32 : dsp_audio_alaw_to_s32;
        dsp_audio_generate_s2law_table();
        dsp_audio_generate_seven();
        dsp_audio_generate_mix_table();
        if (dsp_options & DSP_OPT_ULAW)
                dsp_audio_generate_ulaw_samples();
        dsp_audio_generate_volume_changes();

        err = dsp_pipeline_module_init();
        if (err) {
                printk(KERN_ERR "mISDN_dsp: Can't initialize pipeline, "
                       "error(%d)\n", err);
                return err;
        }

        err = mISDN_register_Bprotocol(&DSP);
        if (err) {
                printk(KERN_ERR "Can't register %s error(%d)\n", DSP.name, err);
                return err;
        }

        /* set sample timer */
        timer_setup(&dsp_spl_tl, dsp_cmx_send, 0);
        dsp_spl_tl.expires = jiffies + dsp_tics;
        dsp_spl_jiffies = dsp_spl_tl.expires;
        add_timer(&dsp_spl_tl);

        return 0;
}


static void __exit dsp_cleanup(void)
{
        mISDN_unregister_Bprotocol(&DSP);

        timer_delete_sync(&dsp_spl_tl);

        if (!list_empty(&dsp_ilist)) {
                printk(KERN_ERR "mISDN_dsp: Audio DSP object inst list not "
                       "empty.\n");
        }
        if (!list_empty(&conf_ilist)) {
                printk(KERN_ERR "mISDN_dsp: Conference list not empty. Not "
                       "all memory freed.\n");
        }

        dsp_pipeline_module_exit();
}

module_init(dsp_init);
module_exit(dsp_cleanup);