Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / isdn / mISDN / dsp_core.c
diff --git a/kernel/drivers/isdn/mISDN/dsp_core.c b/kernel/drivers/isdn/mISDN/dsp_core.c
new file mode 100644 (file)
index 0000000..0222b1a
--- /dev/null
@@ -0,0 +1,1237 @@
+/*
+ * 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
+ *             For changes and modifications please read
+ *             ../../../Documentation/isdn/mISDN.cert
+ *
+ * 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 swithed 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_LICENSE("GPL");
+
+/*int spinnest = 0;*/
+
+spinlock_t dsp_lock; /* global dsp lock */
+struct list_head dsp_ilist;
+struct 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))
+                       del_timer(&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;
+       int             err = 0;
+
+       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))
+                       del_timer(&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 err;
+}
+
+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 */
+       ndsp->tone.tl.function = (void *)dsp_tone_timeout;
+       ndsp->tone.tl.data = (long) ndsp;
+       init_timer(&ndsp->tone.tl);
+
+       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);
+
+       spin_lock_init(&dsp_lock);
+       INIT_LIST_HEAD(&dsp_ilist);
+       INIT_LIST_HEAD(&conf_ilist);
+
+       /* 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 */
+       dsp_spl_tl.function = (void *)dsp_cmx_send;
+       dsp_spl_tl.data = 0;
+       init_timer(&dsp_spl_tl);
+       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);
+
+       del_timer_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);