]> git.karo-electronics.de Git - mv-sheeva.git/blobdiff - drivers/isdn/mISDN/dsp_cmx.c
Add mISDN DSP
[mv-sheeva.git] / drivers / isdn / mISDN / dsp_cmx.c
diff --git a/drivers/isdn/mISDN/dsp_cmx.c b/drivers/isdn/mISDN/dsp_cmx.c
new file mode 100644 (file)
index 0000000..e92b1ba
--- /dev/null
@@ -0,0 +1,1886 @@
+/*
+ * Audio crossconnecting/conferrencing (hardware level).
+ *
+ * Copyright 2002 by Andreas Eversberg (jolly@eversberg.eu)
+ *
+ * This software may be used and distributed according to the terms
+ * of the GNU General Public License, incorporated herein by reference.
+ *
+ */
+
+/*
+ * The process of adding and removing parties to/from a conference:
+ *
+ * There is a chain of struct dsp_conf which has one or more members in a chain
+ * of struct dsp_conf_member.
+ *
+ * After a party is added, the conference is checked for hardware capability.
+ * Also if a party is removed, the conference is checked again.
+ *
+ * There are 3 different solutions: -1 = software, 0 = hardware-crossconnect
+ * 1-n = hardware-conference. The n will give the conference number.
+ *
+ * Depending on the change after removal or insertion of a party, hardware
+ * commands are given.
+ *
+ * The current solution is stored within the struct dsp_conf entry.
+ */
+
+/*
+ * HOW THE CMX WORKS:
+ *
+ * There are 3 types of interaction: One member is alone, in this case only
+ * data flow from upper to lower layer is done.
+ * Two members will also exchange their data so they are crossconnected.
+ * Three or more members will be added in a conference and will hear each
+ * other but will not receive their own speech (echo) if not enabled.
+ *
+ * Features of CMX are:
+ *  - Crossconnecting or even conference, if more than two members are together.
+ *  - Force mixing of transmit data with other crossconnect/conference members.
+ *  - Echo generation to benchmark the delay of audio processing.
+ *  - Use hardware to minimize cpu load, disable FIFO load and minimize delay.
+ *  - Dejittering and clock generation.
+ *
+ * There are 2 buffers:
+ *
+ *
+ * RX-Buffer
+ *                 R             W
+ *                 |             |
+ * ----------------+-------------+-------------------
+ *
+ * The rx-buffer is a ring buffer used to store the received data for each
+ * individual member. This is only the case if data needs to be dejittered
+ * or in case of a conference where different clocks require reclocking.
+ * The transmit-clock (R) will read the buffer.
+ * If the clock overruns the write-pointer, we will have a buffer underrun.
+ * If the write pointer always has a certain distance from the transmit-
+ * clock, we will have a delay. The delay will dynamically be increased and
+ * reduced.
+ *
+ *
+ * TX-Buffer
+ *                  R        W
+ *                  |        |
+ * -----------------+--------+-----------------------
+ *
+ * The tx-buffer is a ring buffer to queue the transmit data from user space
+ * until it will be mixed or sent. There are two pointers, R and W. If the write
+ * pointer W would reach or overrun R, the buffer would overrun. In this case
+ * (some) data is dropped so that it will not overrun.
+ * Additionally a dynamic dejittering can be enabled. this allows data from
+ * user space that have jitter and different clock source.
+ *
+ *
+ * Clock:
+ *
+ * A Clock is not required, if the data source has exactly one clock. In this
+ * case the data source is forwarded to the destination.
+ *
+ * A Clock is required, because the data source
+ *  - has multiple clocks.
+ *  - has no usable clock due to jitter or packet loss (VoIP).
+ * In this case the system's clock is used. The clock resolution depends on
+ * the jiffie resolution.
+ *
+ * If a member joins a conference:
+ *
+ * - If a member joins, its rx_buff is set to silence and change read pointer
+ *   to transmit clock.
+ *
+ * The procedure of received data from card is explained in cmx_receive.
+ * The procedure of received data from user space is explained in cmx_transmit.
+ * The procedure of transmit data to card is cmx_send.
+ *
+ *
+ * Interaction with other features:
+ *
+ * DTMF:
+ * DTMF decoding is done before the data is crossconnected.
+ *
+ * Volume change:
+ * Changing rx-volume is done before the data is crossconnected. The tx-volume
+ * must be changed whenever data is transmitted to the card by the cmx.
+ *
+ * Tones:
+ * If a tone is enabled, it will be processed whenever data is transmitted to
+ * the card. It will replace the tx-data from the user space.
+ * If tones are generated by hardware, this conference member is removed for
+ * this time.
+ *
+ * Disable rx-data:
+ * If cmx is realized in hardware, rx data will be disabled if requested by
+ * the upper layer. If dtmf decoding is done by software and enabled, rx data
+ * will not be diabled but blocked to the upper layer.
+ *
+ * HFC conference engine:
+ * If it is possible to realize all features using hardware, hardware will be
+ * used if not forbidden by control command. Disabling rx-data provides
+ * absolutely traffic free audio processing. (except for the quick 1-frame
+ * upload of a tone loop, only once for a new tone)
+ *
+ */
+
+/* delay.h is required for hw_lock.h */
+
+#include <linux/delay.h>
+#include <linux/mISDNif.h>
+#include <linux/mISDNdsp.h>
+#include "core.h"
+#include "dsp.h"
+/*
+ * debugging of multi party conference,
+ * by using conference even with two members
+ */
+
+/* #define CMX_CONF_DEBUG */
+
+/*#define CMX_DEBUG * massive read/write pointer output */
+/*#define CMX_TX_DEBUG * massive read/write on tx-buffer with content */
+
+static inline int
+count_list_member(struct list_head *head)
+{
+       int                     cnt = 0;
+       struct list_head        *m;
+
+       list_for_each(m, head)
+               cnt++;
+       return cnt;
+}
+
+/*
+ * debug cmx memory structure
+ */
+void
+dsp_cmx_debug(struct dsp *dsp)
+{
+       struct dsp_conf *conf;
+       struct dsp_conf_member  *member;
+       struct dsp              *odsp;
+
+       printk(KERN_DEBUG "-----Current DSP\n");
+       list_for_each_entry(odsp, &dsp_ilist, list) {
+               printk(KERN_DEBUG "* %s echo=%d txmix=%d",
+                   odsp->name, odsp->echo, odsp->tx_mix);
+               if (odsp->conf)
+                       printk(" (Conf %d)", odsp->conf->id);
+               if (dsp == odsp)
+                       printk(" *this*");
+               printk("\n");
+       }
+       printk(KERN_DEBUG "-----Current Conf:\n");
+       list_for_each_entry(conf, &conf_ilist, list) {
+               printk(KERN_DEBUG "* Conf %d (%p)\n", conf->id, conf);
+               list_for_each_entry(member, &conf->mlist, list) {
+                       printk(KERN_DEBUG
+                           "  - member = %s (slot_tx %d, bank_tx %d, "
+                           "slot_rx %d, bank_rx %d hfc_conf %d)%s\n",
+                           member->dsp->name, member->dsp->pcm_slot_tx,
+                           member->dsp->pcm_bank_tx, member->dsp->pcm_slot_rx,
+                           member->dsp->pcm_bank_rx, member->dsp->hfc_conf,
+                           (member->dsp == dsp) ? " *this*" : "");
+               }
+       }
+       printk(KERN_DEBUG "-----end\n");
+}
+
+/*
+ * search conference
+ */
+static struct dsp_conf *
+dsp_cmx_search_conf(u32 id)
+{
+       struct dsp_conf *conf;
+
+       if (!id) {
+               printk(KERN_WARNING "%s: conference ID is 0.\n", __func__);
+               return NULL;
+       }
+
+       /* search conference */
+       list_for_each_entry(conf, &conf_ilist, list)
+               if (conf->id == id)
+                       return conf;
+
+       return NULL;
+}
+
+
+/*
+ * add member to conference
+ */
+static int
+dsp_cmx_add_conf_member(struct dsp *dsp, struct dsp_conf *conf)
+{
+       struct dsp_conf_member *member;
+
+       if (!conf || !dsp) {
+               printk(KERN_WARNING "%s: conf or dsp is 0.\n", __func__);
+               return -EINVAL;
+       }
+       if (dsp->member) {
+               printk(KERN_WARNING "%s: dsp is already member in a conf.\n",
+                       __func__);
+               return -EINVAL;
+       }
+
+       if (dsp->conf) {
+               printk(KERN_WARNING "%s: dsp is already in a conf.\n",
+                       __func__);
+               return -EINVAL;
+       }
+
+       member = kzalloc(sizeof(struct dsp_conf_member), GFP_ATOMIC);
+       if (!member) {
+               printk(KERN_ERR "kmalloc struct dsp_conf_member failed\n");
+               return -ENOMEM;
+       }
+       member->dsp = dsp;
+       /* clear rx buffer */
+       memset(dsp->rx_buff, dsp_silence, sizeof(dsp->rx_buff));
+       dsp->rx_init = 1; /* rx_W and rx_R will be adjusted on first frame */
+       dsp->rx_W = 0;
+       dsp->rx_R = 0;
+
+       list_add_tail(&member->list, &conf->mlist);
+
+       dsp->conf = conf;
+       dsp->member = member;
+
+       return 0;
+}
+
+
+/*
+ * del member from conference
+ */
+int
+dsp_cmx_del_conf_member(struct dsp *dsp)
+{
+       struct dsp_conf_member *member;
+
+       if (!dsp) {
+               printk(KERN_WARNING "%s: dsp is 0.\n",
+                       __func__);
+               return -EINVAL;
+       }
+
+       if (!dsp->conf) {
+               printk(KERN_WARNING "%s: dsp is not in a conf.\n",
+                       __func__);
+               return -EINVAL;
+       }
+
+       if (list_empty(&dsp->conf->mlist)) {
+               printk(KERN_WARNING "%s: dsp has linked an empty conf.\n",
+                       __func__);
+               return -EINVAL;
+       }
+
+       /* find us in conf */
+       list_for_each_entry(member, &dsp->conf->mlist, list) {
+               if (member->dsp == dsp) {
+                       list_del(&member->list);
+                       dsp->conf = NULL;
+                       dsp->member = NULL;
+                       kfree(member);
+                       return 0;
+               }
+       }
+       printk(KERN_WARNING
+           "%s: dsp is not present in its own conf_meber list.\n",
+           __func__);
+
+       return -EINVAL;
+}
+
+
+/*
+ * new conference
+ */
+static struct dsp_conf
+*dsp_cmx_new_conf(u32 id)
+{
+       struct dsp_conf *conf;
+
+       if (!id) {
+               printk(KERN_WARNING "%s: id is 0.\n",
+                   __func__);
+               return NULL;
+       }
+
+       conf = kzalloc(sizeof(struct dsp_conf), GFP_ATOMIC);
+       if (!conf) {
+               printk(KERN_ERR "kmalloc struct dsp_conf failed\n");
+               return NULL;
+       }
+       INIT_LIST_HEAD(&conf->mlist);
+       conf->id = id;
+
+       list_add_tail(&conf->list, &conf_ilist);
+
+       return conf;
+}
+
+
+/*
+ * del conference
+ */
+int
+dsp_cmx_del_conf(struct dsp_conf *conf)
+{
+       if (!conf) {
+               printk(KERN_WARNING "%s: conf is null.\n",
+                   __func__);
+               return -EINVAL;
+       }
+
+       if (!list_empty(&conf->mlist)) {
+               printk(KERN_WARNING "%s: conf not empty.\n",
+                   __func__);
+               return -EINVAL;
+       }
+       list_del(&conf->list);
+       kfree(conf);
+
+       return 0;
+}
+
+
+/*
+ * send HW message to hfc card
+ */
+static void
+dsp_cmx_hw_message(struct dsp *dsp, u32 message, u32 param1, u32 param2,
+    u32 param3, u32 param4)
+{
+       struct mISDN_ctrl_req cq;
+
+       memset(&cq, 0, sizeof(cq));
+       cq.op = message;
+       cq.p1 = param1 | (param2 << 8);
+       cq.p2 = param3 | (param4 << 8);
+       if (dsp->ch.peer)
+               dsp->ch.peer->ctrl(dsp->ch.peer, CONTROL_CHANNEL, &cq);
+}
+
+
+/*
+ * do hardware update and set the software/hardware flag
+ *
+ * either a conference or a dsp instance can be given
+ * if only dsp instance is given, the instance is not associated with a conf
+ * and therefore removed. if a conference is given, the dsp is expected to
+ * be member of that conference.
+ */
+void
+dsp_cmx_hardware(struct dsp_conf *conf, struct dsp *dsp)
+{
+       struct dsp_conf_member  *member, *nextm;
+       struct dsp              *finddsp;
+       int             memb = 0, i, ii, i1, i2;
+       int             freeunits[8];
+       u_char          freeslots[256];
+       int             same_hfc = -1, same_pcm = -1, current_conf = -1,
+           all_conf = 1;
+
+       /* dsp gets updated (no conf) */
+       if (!conf) {
+               if (!dsp)
+                       return;
+               if (dsp_debug & DEBUG_DSP_CMX)
+                       printk(KERN_DEBUG "%s checking dsp %s\n",
+                           __func__, dsp->name);
+one_member:
+               /* remove HFC conference if enabled */
+               if (dsp->hfc_conf >= 0) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s removing %s from HFC conf %d "
+                                   "because dsp is split\n", __func__,
+                                   dsp->name, dsp->hfc_conf);
+                       dsp_cmx_hw_message(dsp, MISDN_CTRL_HFC_CONF_SPLIT,
+                           0, 0, 0, 0);
+                       dsp->hfc_conf = -1;
+               }
+               /* process hw echo */
+               if (dsp->features.pcm_banks < 1)
+                       return;
+               if (!dsp->echo) {
+                       /* NO ECHO: remove PCM slot if assigned */
+                       if (dsp->pcm_slot_tx >= 0 || dsp->pcm_slot_rx >= 0) {
+                               if (dsp_debug & DEBUG_DSP_CMX)
+                                       printk(KERN_DEBUG "%s removing %s from"
+                                           " PCM slot %d (TX) %d (RX) because"
+                                           " dsp is split (no echo)\n",
+                                           __func__, dsp->name,
+                                           dsp->pcm_slot_tx, dsp->pcm_slot_rx);
+                               dsp_cmx_hw_message(dsp, MISDN_CTRL_HFC_PCM_DISC,
+                                   0, 0, 0, 0);
+                               dsp->pcm_slot_tx = -1;
+                               dsp->pcm_bank_tx = -1;
+                               dsp->pcm_slot_rx = -1;
+                               dsp->pcm_bank_rx = -1;
+                       }
+                       return;
+               }
+               /* ECHO: already echo */
+               if (dsp->pcm_slot_tx >= 0 && dsp->pcm_slot_rx < 0 &&
+                   dsp->pcm_bank_tx == 2 && dsp->pcm_bank_rx == 2)
+                       return;
+               /* ECHO: if slot already assigned */
+               if (dsp->pcm_slot_tx >= 0) {
+                       dsp->pcm_slot_rx = dsp->pcm_slot_tx;
+                       dsp->pcm_bank_tx = 2; /* 2 means loop */
+                       dsp->pcm_bank_rx = 2;
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s refresh %s for echo using slot %d\n",
+                                   __func__, dsp->name,
+                                   dsp->pcm_slot_tx);
+                       dsp_cmx_hw_message(dsp, MISDN_CTRL_HFC_PCM_CONN,
+                           dsp->pcm_slot_tx, 2, dsp->pcm_slot_rx, 2);
+                       return;
+               }
+               /* ECHO: find slot */
+               dsp->pcm_slot_tx = -1;
+               dsp->pcm_slot_rx = -1;
+               memset(freeslots, 1, sizeof(freeslots));
+               list_for_each_entry(finddsp, &dsp_ilist, list) {
+                       if (finddsp->features.pcm_id == dsp->features.pcm_id) {
+                               if (finddsp->pcm_slot_rx >= 0 &&
+                                   finddsp->pcm_slot_rx < sizeof(freeslots))
+                                       freeslots[finddsp->pcm_slot_tx] = 0;
+                               if (finddsp->pcm_slot_tx >= 0 &&
+                                   finddsp->pcm_slot_tx < sizeof(freeslots))
+                                       freeslots[finddsp->pcm_slot_rx] = 0;
+                       }
+               }
+               i = 0;
+               ii = dsp->features.pcm_slots;
+               while (i < ii) {
+                       if (freeslots[i])
+                               break;
+                       i++;
+               }
+               if (i == ii) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s no slot available for echo\n",
+                                   __func__);
+                       /* no more slots available */
+                       return;
+               }
+               /* assign free slot */
+               dsp->pcm_slot_tx = i;
+               dsp->pcm_slot_rx = i;
+               dsp->pcm_bank_tx = 2; /* loop */
+               dsp->pcm_bank_rx = 2;
+               if (dsp_debug & DEBUG_DSP_CMX)
+                       printk(KERN_DEBUG
+                           "%s assign echo for %s using slot %d\n",
+                           __func__, dsp->name, dsp->pcm_slot_tx);
+               dsp_cmx_hw_message(dsp, MISDN_CTRL_HFC_PCM_CONN,
+                   dsp->pcm_slot_tx, 2, dsp->pcm_slot_rx, 2);
+               return;
+       }
+
+       /* conf gets updated (all members) */
+       if (dsp_debug & DEBUG_DSP_CMX)
+               printk(KERN_DEBUG "%s checking conference %d\n",
+                   __func__, conf->id);
+
+       if (list_empty(&conf->mlist)) {
+               printk(KERN_ERR "%s: conference whithout members\n",
+                   __func__);
+               return;
+       }
+       member = list_entry(conf->mlist.next, struct dsp_conf_member, list);
+       same_hfc = member->dsp->features.hfc_id;
+       same_pcm = member->dsp->features.pcm_id;
+       /* check all members in our conference */
+       list_for_each_entry(member, &conf->mlist, list) {
+               /* check if member uses mixing */
+               if (member->dsp->tx_mix) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s dsp %s cannot form a conf, because "
+                                   "tx_mix is turned on\n", __func__,
+                                   member->dsp->name);
+conf_software:
+                       list_for_each_entry(member, &conf->mlist, list) {
+                               dsp = member->dsp;
+                               /* remove HFC conference if enabled */
+                               if (dsp->hfc_conf >= 0) {
+                                       if (dsp_debug & DEBUG_DSP_CMX)
+                                               printk(KERN_DEBUG
+                                                   "%s removing %s from HFC "
+                                                   "conf %d because not "
+                                                   "possible with hardware\n",
+                                                   __func__,
+                                                   dsp->name,
+                                                   dsp->hfc_conf);
+                                       dsp_cmx_hw_message(dsp,
+                                           MISDN_CTRL_HFC_CONF_SPLIT,
+                                           0, 0, 0, 0);
+                                       dsp->hfc_conf = -1;
+                               }
+                               /* remove PCM slot if assigned */
+                               if (dsp->pcm_slot_tx >= 0 ||
+                                   dsp->pcm_slot_rx >= 0) {
+                                       if (dsp_debug & DEBUG_DSP_CMX)
+                                               printk(KERN_DEBUG "%s removing "
+                                                   "%s from PCM slot %d (TX)"
+                                                   " slot %d (RX) because not"
+                                                   " possible with hardware\n",
+                                                   __func__,
+                                                   dsp->name,
+                                                   dsp->pcm_slot_tx,
+                                                   dsp->pcm_slot_rx);
+                                       dsp_cmx_hw_message(dsp,
+                                           MISDN_CTRL_HFC_PCM_DISC,
+                                           0, 0, 0, 0);
+                                       dsp->pcm_slot_tx = -1;
+                                       dsp->pcm_bank_tx = -1;
+                                       dsp->pcm_slot_rx = -1;
+                                       dsp->pcm_bank_rx = -1;
+                               }
+                       }
+                       conf->hardware = 0;
+                       conf->software = 1;
+                       return;
+               }
+               /* check if member has echo turned on */
+               if (member->dsp->echo) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s dsp %s cannot form a conf, because "
+                                   "echo is turned on\n", __func__,
+                                   member->dsp->name);
+                       goto conf_software;
+               }
+               /* check if member has tx_mix turned on */
+               if (member->dsp->tx_mix) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s dsp %s cannot form a conf, because "
+                                   "tx_mix is turned on\n",
+                                   __func__, member->dsp->name);
+                       goto conf_software;
+               }
+               /* check if member changes volume at an not suppoted level */
+               if (member->dsp->tx_volume) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s dsp %s cannot form a conf, because "
+                                   "tx_volume is changed\n",
+                                   __func__, member->dsp->name);
+                       goto conf_software;
+               }
+               if (member->dsp->rx_volume) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s dsp %s cannot form a conf, because "
+                                   "rx_volume is changed\n",
+                                   __func__, member->dsp->name);
+                       goto conf_software;
+               }
+               /* check if tx-data turned on */
+               if (member->dsp->tx_data) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s dsp %s cannot form a conf, because "
+                                   "tx_data is turned on\n",
+                                   __func__, member->dsp->name);
+                       goto conf_software;
+               }
+               /* check if pipeline exists */
+               if (member->dsp->pipeline.inuse) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s dsp %s cannot form a conf, because "
+                                   "pipeline exists\n", __func__,
+                                   member->dsp->name);
+                       goto conf_software;
+               }
+               /* check if encryption is enabled */
+               if (member->dsp->bf_enable) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG "%s dsp %s cannot form a "
+                                   "conf, because encryption is enabled\n",
+                                   __func__, member->dsp->name);
+                       goto conf_software;
+               }
+               /* check if member is on a card with PCM support */
+               if (member->dsp->features.pcm_id < 0) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s dsp %s cannot form a conf, because "
+                                   "dsp has no PCM bus\n",
+                                   __func__, member->dsp->name);
+                       goto conf_software;
+               }
+               /* check if relations are on the same PCM bus */
+               if (member->dsp->features.pcm_id != same_pcm) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s dsp %s cannot form a conf, because "
+                                   "dsp is on a different PCM bus than the "
+                                   "first dsp\n",
+                                   __func__, member->dsp->name);
+                       goto conf_software;
+               }
+               /* determine if members are on the same hfc chip */
+               if (same_hfc != member->dsp->features.hfc_id)
+                       same_hfc = -1;
+               /* if there are members already in a conference */
+               if (current_conf < 0 && member->dsp->hfc_conf >= 0)
+                       current_conf = member->dsp->hfc_conf;
+               /* if any member is not in a conference */
+               if (member->dsp->hfc_conf < 0)
+                       all_conf = 0;
+
+               memb++;
+       }
+
+       /* if no member, this is an error */
+       if (memb < 1)
+               return;
+
+       /* one member */
+       if (memb == 1) {
+               if (dsp_debug & DEBUG_DSP_CMX)
+                       printk(KERN_DEBUG
+                           "%s conf %d cannot form a HW conference, "
+                           "because dsp is alone\n", __func__, conf->id);
+               conf->hardware = 0;
+               conf->software = 0;
+               member = list_entry(conf->mlist.next, struct dsp_conf_member,
+                       list);
+               dsp = member->dsp;
+               goto one_member;
+       }
+
+       /*
+        * ok, now we are sure that all members are on the same pcm.
+        * now we will see if we have only two members, so we can do
+        * crossconnections, which don't have any limitations.
+        */
+
+       /* if we have only two members */
+       if (memb == 2) {
+               member = list_entry(conf->mlist.next, struct dsp_conf_member,
+                       list);
+               nextm = list_entry(member->list.next, struct dsp_conf_member,
+                       list);
+               /* remove HFC conference if enabled */
+               if (member->dsp->hfc_conf >= 0) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s removing %s from HFC conf %d because "
+                                   "two parties require only a PCM slot\n",
+                                   __func__, member->dsp->name,
+                                   member->dsp->hfc_conf);
+                       dsp_cmx_hw_message(member->dsp,
+                           MISDN_CTRL_HFC_CONF_SPLIT, 0, 0, 0, 0);
+                       member->dsp->hfc_conf = -1;
+               }
+               if (nextm->dsp->hfc_conf >= 0) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s removing %s from HFC conf %d because "
+                                   "two parties require only a PCM slot\n",
+                                   __func__, nextm->dsp->name,
+                                   nextm->dsp->hfc_conf);
+                       dsp_cmx_hw_message(nextm->dsp,
+                           MISDN_CTRL_HFC_CONF_SPLIT, 0, 0, 0, 0);
+                       nextm->dsp->hfc_conf = -1;
+               }
+               /* if members have two banks (and not on the same chip) */
+               if (member->dsp->features.pcm_banks > 1 &&
+                   nextm->dsp->features.pcm_banks > 1 &&
+                   member->dsp->features.hfc_id !=
+                   nextm->dsp->features.hfc_id) {
+                       /* if both members have same slots with crossed banks */
+                       if (member->dsp->pcm_slot_tx >= 0 &&
+                           member->dsp->pcm_slot_rx >= 0 &&
+                           nextm->dsp->pcm_slot_tx >= 0 &&
+                           nextm->dsp->pcm_slot_rx >= 0 &&
+                           nextm->dsp->pcm_slot_tx ==
+                           member->dsp->pcm_slot_rx &&
+                           nextm->dsp->pcm_slot_rx ==
+                           member->dsp->pcm_slot_tx &&
+                           nextm->dsp->pcm_slot_tx ==
+                           member->dsp->pcm_slot_tx &&
+                           member->dsp->pcm_bank_tx !=
+                           member->dsp->pcm_bank_rx &&
+                           nextm->dsp->pcm_bank_tx !=
+                           nextm->dsp->pcm_bank_rx) {
+                               /* all members have same slot */
+                               if (dsp_debug & DEBUG_DSP_CMX)
+                                       printk(KERN_DEBUG
+                                           "%s dsp %s & %s stay joined on "
+                                           "PCM slot %d bank %d (TX) bank %d "
+                                           "(RX) (on different chips)\n",
+                                           __func__,
+                                           member->dsp->name,
+                                           nextm->dsp->name,
+                                           member->dsp->pcm_slot_tx,
+                                           member->dsp->pcm_bank_tx,
+                                           member->dsp->pcm_bank_rx);
+                               conf->hardware = 0;
+                               conf->software = 1;
+                               return;
+                       }
+                       /* find a new slot */
+                       memset(freeslots, 1, sizeof(freeslots));
+                       list_for_each_entry(dsp, &dsp_ilist, list) {
+                               if (dsp != member->dsp &&
+                                   dsp != nextm->dsp &&
+                                   member->dsp->features.pcm_id ==
+                                   dsp->features.pcm_id) {
+                                       if (dsp->pcm_slot_rx >= 0 &&
+                                           dsp->pcm_slot_rx <
+                                           sizeof(freeslots))
+                                               freeslots[dsp->pcm_slot_tx] = 0;
+                                       if (dsp->pcm_slot_tx >= 0 &&
+                                           dsp->pcm_slot_tx <
+                                           sizeof(freeslots))
+                                               freeslots[dsp->pcm_slot_rx] = 0;
+                               }
+                       }
+                       i = 0;
+                       ii = member->dsp->features.pcm_slots;
+                       while (i < ii) {
+                               if (freeslots[i])
+                                       break;
+                               i++;
+                       }
+                       if (i == ii) {
+                               if (dsp_debug & DEBUG_DSP_CMX)
+                                       printk(KERN_DEBUG
+                                           "%s no slot available for "
+                                           "%s & %s\n", __func__,
+                                           member->dsp->name,
+                                           nextm->dsp->name);
+                               /* no more slots available */
+                               goto conf_software;
+                       }
+                       /* assign free slot */
+                       member->dsp->pcm_slot_tx = i;
+                       member->dsp->pcm_slot_rx = i;
+                       nextm->dsp->pcm_slot_tx = i;
+                       nextm->dsp->pcm_slot_rx = i;
+                       member->dsp->pcm_bank_rx = 0;
+                       member->dsp->pcm_bank_tx = 1;
+                       nextm->dsp->pcm_bank_rx = 1;
+                       nextm->dsp->pcm_bank_tx = 0;
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s adding %s & %s to new PCM slot %d "
+                                   "(TX and RX on different chips) because "
+                                   "both members have not same slots\n",
+                                   __func__,
+                                   member->dsp->name,
+                                   nextm->dsp->name,
+                                   member->dsp->pcm_slot_tx);
+                       dsp_cmx_hw_message(member->dsp, MISDN_CTRL_HFC_PCM_CONN,
+                           member->dsp->pcm_slot_tx, member->dsp->pcm_bank_tx,
+                           member->dsp->pcm_slot_rx, member->dsp->pcm_bank_rx);
+                       dsp_cmx_hw_message(nextm->dsp, MISDN_CTRL_HFC_PCM_CONN,
+                           nextm->dsp->pcm_slot_tx, nextm->dsp->pcm_bank_tx,
+                           nextm->dsp->pcm_slot_rx, nextm->dsp->pcm_bank_rx);
+                       conf->hardware = 1;
+                       conf->software = 0;
+                       return;
+               /* if members have one bank (or on the same chip) */
+               } else {
+                       /* if both members have different crossed slots */
+                       if (member->dsp->pcm_slot_tx >= 0 &&
+                           member->dsp->pcm_slot_rx >= 0 &&
+                           nextm->dsp->pcm_slot_tx >= 0 &&
+                           nextm->dsp->pcm_slot_rx >= 0 &&
+                           nextm->dsp->pcm_slot_tx ==
+                           member->dsp->pcm_slot_rx &&
+                           nextm->dsp->pcm_slot_rx ==
+                           member->dsp->pcm_slot_tx &&
+                           member->dsp->pcm_slot_tx !=
+                           member->dsp->pcm_slot_rx &&
+                           member->dsp->pcm_bank_tx == 0 &&
+                           member->dsp->pcm_bank_rx == 0 &&
+                           nextm->dsp->pcm_bank_tx == 0 &&
+                           nextm->dsp->pcm_bank_rx == 0) {
+                               /* all members have same slot */
+                               if (dsp_debug & DEBUG_DSP_CMX)
+                                       printk(KERN_DEBUG
+                                           "%s dsp %s & %s stay joined on PCM "
+                                           "slot %d (TX) %d (RX) on same chip "
+                                           "or one bank PCM)\n", __func__,
+                                           member->dsp->name,
+                                           nextm->dsp->name,
+                                           member->dsp->pcm_slot_tx,
+                                           member->dsp->pcm_slot_rx);
+                               conf->hardware = 0;
+                               conf->software = 1;
+                               return;
+                       }
+                       /* find two new slot */
+                       memset(freeslots, 1, sizeof(freeslots));
+                       list_for_each_entry(dsp, &dsp_ilist, list) {
+                               if (dsp != member->dsp &&
+                                   dsp != nextm->dsp &&
+                                   member->dsp->features.pcm_id ==
+                                   dsp->features.pcm_id) {
+                                       if (dsp->pcm_slot_rx >= 0 &&
+                                           dsp->pcm_slot_rx <
+                                           sizeof(freeslots))
+                                               freeslots[dsp->pcm_slot_tx] = 0;
+                                       if (dsp->pcm_slot_tx >= 0 &&
+                                           dsp->pcm_slot_tx <
+                                           sizeof(freeslots))
+                                               freeslots[dsp->pcm_slot_rx] = 0;
+                               }
+                       }
+                       i1 = 0;
+                       ii = member->dsp->features.pcm_slots;
+                       while (i1 < ii) {
+                               if (freeslots[i1])
+                                       break;
+                               i1++;
+                       }
+                       if (i1 == ii) {
+                               if (dsp_debug & DEBUG_DSP_CMX)
+                                       printk(KERN_DEBUG
+                                           "%s no slot available "
+                                           "for %s & %s\n", __func__,
+                                           member->dsp->name,
+                                           nextm->dsp->name);
+                               /* no more slots available */
+                               goto conf_software;
+                       }
+                       i2 = i1+1;
+                       while (i2 < ii) {
+                               if (freeslots[i2])
+                                       break;
+                               i2++;
+                       }
+                       if (i2 == ii) {
+                               if (dsp_debug & DEBUG_DSP_CMX)
+                                       printk(KERN_DEBUG
+                                           "%s no slot available "
+                                           "for %s & %s\n",
+                                           __func__,
+                                           member->dsp->name,
+                                           nextm->dsp->name);
+                               /* no more slots available */
+                               goto conf_software;
+                       }
+                       /* assign free slots */
+                       member->dsp->pcm_slot_tx = i1;
+                       member->dsp->pcm_slot_rx = i2;
+                       nextm->dsp->pcm_slot_tx = i2;
+                       nextm->dsp->pcm_slot_rx = i1;
+                       member->dsp->pcm_bank_rx = 0;
+                       member->dsp->pcm_bank_tx = 0;
+                       nextm->dsp->pcm_bank_rx = 0;
+                       nextm->dsp->pcm_bank_tx = 0;
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s adding %s & %s to new PCM slot %d "
+                                   "(TX) %d (RX) on same chip or one bank "
+                                   "PCM, because both members have not "
+                                   "crossed slots\n", __func__,
+                                   member->dsp->name,
+                                   nextm->dsp->name,
+                                   member->dsp->pcm_slot_tx,
+                                   member->dsp->pcm_slot_rx);
+                       dsp_cmx_hw_message(member->dsp, MISDN_CTRL_HFC_PCM_CONN,
+                           member->dsp->pcm_slot_tx, member->dsp->pcm_bank_tx,
+                           member->dsp->pcm_slot_rx, member->dsp->pcm_bank_rx);
+                       dsp_cmx_hw_message(nextm->dsp, MISDN_CTRL_HFC_PCM_CONN,
+                           nextm->dsp->pcm_slot_tx, nextm->dsp->pcm_bank_tx,
+                           nextm->dsp->pcm_slot_rx, nextm->dsp->pcm_bank_rx);
+                       conf->hardware = 1;
+                       conf->software = 0;
+                       return;
+               }
+       }
+
+       /*
+        * if we have more than two, we may check if we have a conference
+        * unit available on the chip. also all members must be on the same
+        */
+
+       /* if not the same HFC chip */
+       if (same_hfc < 0) {
+               if (dsp_debug & DEBUG_DSP_CMX)
+                       printk(KERN_DEBUG
+                           "%s conference %d cannot be formed, because "
+                           "members are on different chips or not "
+                           "on HFC chip\n",
+                           __func__, conf->id);
+               goto conf_software;
+       }
+
+       /* for more than two members.. */
+
+       /* in case of hdlc, we change to software */
+       if (dsp->hdlc)
+               goto conf_software;
+
+       /* if all members already have the same conference */
+       if (all_conf)
+               return;
+
+       /*
+        * if there is an existing conference, but not all members have joined
+        */
+       if (current_conf >= 0) {
+join_members:
+               list_for_each_entry(member, &conf->mlist, list) {
+                       /* join to current conference */
+                       if (member->dsp->hfc_conf == current_conf)
+                               continue;
+                       /* get a free timeslot first */
+                       memset(freeslots, 1, sizeof(freeslots));
+                       list_for_each_entry(dsp, &dsp_ilist, list) {
+                               /*
+                                * not checking current member, because
+                                * slot will be overwritten.
+                                */
+                               if (
+                                   dsp != member->dsp &&
+                               /* dsp must be on the same PCM */
+                                   member->dsp->features.pcm_id ==
+                                   dsp->features.pcm_id) {
+                                       /* dsp must be on a slot */
+                                       if (dsp->pcm_slot_tx >= 0 &&
+                                           dsp->pcm_slot_tx <
+                                           sizeof(freeslots))
+                                               freeslots[dsp->pcm_slot_tx] = 0;
+                                       if (dsp->pcm_slot_rx >= 0 &&
+                                           dsp->pcm_slot_rx <
+                                           sizeof(freeslots))
+                                               freeslots[dsp->pcm_slot_rx] = 0;
+                               }
+                       }
+                       i = 0;
+                       ii = member->dsp->features.pcm_slots;
+                       while (i < ii) {
+                               if (freeslots[i])
+                                       break;
+                               i++;
+                       }
+                       if (i == ii) {
+                               /* no more slots available */
+                               if (dsp_debug & DEBUG_DSP_CMX)
+                                       printk(KERN_DEBUG
+                                           "%s conference %d cannot be formed,"
+                                           " because no slot free\n",
+                                           __func__, conf->id);
+                               goto conf_software;
+                       }
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "%s changing dsp %s to HW conference "
+                                   "%d slot %d\n", __func__,
+                                   member->dsp->name, current_conf, i);
+                       /* assign free slot & set PCM & join conf */
+                       member->dsp->pcm_slot_tx = i;
+                       member->dsp->pcm_slot_rx = i;
+                       member->dsp->pcm_bank_tx = 2; /* loop */
+                       member->dsp->pcm_bank_rx = 2;
+                       member->dsp->hfc_conf = current_conf;
+                       dsp_cmx_hw_message(member->dsp, MISDN_CTRL_HFC_PCM_CONN,
+                           i, 2, i, 2);
+                       dsp_cmx_hw_message(member->dsp,
+                           MISDN_CTRL_HFC_CONF_JOIN, current_conf, 0, 0, 0);
+               }
+               return;
+       }
+
+       /*
+        * no member is in a conference yet, so we find a free one
+        */
+       memset(freeunits, 1, sizeof(freeunits));
+       list_for_each_entry(dsp, &dsp_ilist, list) {
+               /* dsp must be on the same chip */
+               if (dsp->features.hfc_id == same_hfc &&
+                   /* dsp must have joined a HW conference */
+                   dsp->hfc_conf >= 0 &&
+                   /* slot must be within range */
+                   dsp->hfc_conf < 8)
+                       freeunits[dsp->hfc_conf] = 0;
+       }
+       i = 0;
+       ii = 8;
+       while (i < ii) {
+               if (freeunits[i])
+                       break;
+               i++;
+       }
+       if (i == ii) {
+               /* no more conferences available */
+               if (dsp_debug & DEBUG_DSP_CMX)
+                       printk(KERN_DEBUG
+                           "%s conference %d cannot be formed, because "
+                           "no conference number free\n",
+                           __func__, conf->id);
+               goto conf_software;
+       }
+       /* join all members */
+       current_conf = i;
+       goto join_members;
+}
+
+
+/*
+ * conf_id != 0: join or change conference
+ * conf_id == 0: split from conference if not already
+ */
+int
+dsp_cmx_conf(struct dsp *dsp, u32 conf_id)
+{
+       int err;
+       struct dsp_conf *conf;
+       struct dsp_conf_member  *member;
+
+       /* if conference doesn't change */
+       if (dsp->conf_id == conf_id)
+               return 0;
+
+       /* first remove us from current conf */
+       if (dsp->conf_id) {
+               if (dsp_debug & DEBUG_DSP_CMX)
+                       printk(KERN_DEBUG "removing us from conference %d\n",
+                               dsp->conf->id);
+               /* remove us from conf */
+               conf = dsp->conf;
+               err = dsp_cmx_del_conf_member(dsp);
+               if (err)
+                       return err;
+               dsp->conf_id = 0;
+
+               /* update hardware */
+               dsp_cmx_hardware(NULL, dsp);
+
+               /* conf now empty? */
+               if (list_empty(&conf->mlist)) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "conference is empty, so we remove it.\n");
+                       err = dsp_cmx_del_conf(conf);
+                       if (err)
+                               return err;
+               } else {
+                       /* update members left on conf */
+                       dsp_cmx_hardware(conf, NULL);
+               }
+       }
+
+       /* if split */
+       if (!conf_id)
+               return 0;
+
+       /* now add us to conf */
+       if (dsp_debug & DEBUG_DSP_CMX)
+               printk(KERN_DEBUG "searching conference %d\n",
+                       conf_id);
+       conf = dsp_cmx_search_conf(conf_id);
+       if (!conf) {
+               if (dsp_debug & DEBUG_DSP_CMX)
+                       printk(KERN_DEBUG
+                           "conference doesn't exist yet, creating.\n");
+               /* the conference doesn't exist, so we create */
+               conf = dsp_cmx_new_conf(conf_id);
+               if (!conf)
+                       return -EINVAL;
+       } else if (!list_empty(&conf->mlist)) {
+               member = list_entry(conf->mlist.next, struct dsp_conf_member,
+                       list);
+               if (dsp->hdlc && !member->dsp->hdlc) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "cannot join transparent conference.\n");
+                       return -EINVAL;
+               }
+               if (!dsp->hdlc && member->dsp->hdlc) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "cannot join hdlc conference.\n");
+                       return -EINVAL;
+               }
+       }
+       /* add conference member */
+       err = dsp_cmx_add_conf_member(dsp, conf);
+       if (err)
+               return err;
+       dsp->conf_id = conf_id;
+
+       /* if we are alone, we do nothing! */
+       if (list_empty(&conf->mlist)) {
+               if (dsp_debug & DEBUG_DSP_CMX)
+                       printk(KERN_DEBUG
+                           "we are alone in this conference, so exit.\n");
+               /* update hardware */
+               dsp_cmx_hardware(NULL, dsp);
+               return 0;
+       }
+
+       /* update members on conf */
+       dsp_cmx_hardware(conf, NULL);
+
+       return 0;
+}
+
+
+/*
+ * audio data is received from card
+ */
+void
+dsp_cmx_receive(struct dsp *dsp, struct sk_buff *skb)
+{
+       u8 *d, *p;
+       int len = skb->len;
+       struct mISDNhead *hh = mISDN_HEAD_P(skb);
+       int w, i, ii;
+
+       /* check if we have sompen */
+       if (len < 1)
+               return;
+
+       /* half of the buffer should be larger than maximum packet size */
+       if (len >= CMX_BUFF_HALF) {
+               printk(KERN_ERR
+                   "%s line %d: packet from card is too large (%d bytes). "
+                   "please make card send smaller packets OR increase "
+                   "CMX_BUFF_SIZE\n", __FILE__, __LINE__, len);
+               return;
+       }
+
+       /*
+        * initialize pointers if not already -
+        * also add delay if requested by PH_SIGNAL
+        */
+       if (dsp->rx_init) {
+               dsp->rx_init = 0;
+               if (dsp->features.unordered) {
+                       dsp->rx_R = (hh->id & CMX_BUFF_MASK);
+                       dsp->rx_W = (dsp->rx_R + dsp->cmx_delay)
+                               & CMX_BUFF_MASK;
+               } else {
+                       dsp->rx_R = 0;
+                       dsp->rx_W = dsp->cmx_delay;
+               }
+       }
+       /* if frame contains time code, write directly */
+       if (dsp->features.unordered) {
+               dsp->rx_W = (hh->id & CMX_BUFF_MASK);
+               /* printk(KERN_DEBUG "%s %08x\n", dsp->name, hh->id); */
+       }
+       /*
+        * if we underrun (or maybe overrun),
+        * we set our new read pointer, and write silence to buffer
+        */
+       if (((dsp->rx_W-dsp->rx_R) & CMX_BUFF_MASK) >= CMX_BUFF_HALF) {
+               if (dsp_debug & DEBUG_DSP_CMX)
+                       printk(KERN_DEBUG
+                           "cmx_receive(dsp=%lx): UNDERRUN (or overrun the "
+                           "maximum delay), adjusting read pointer! "
+                           "(inst %s)\n", (u_long)dsp, dsp->name);
+               /* flush buffer */
+               if (dsp->features.unordered) {
+                       dsp->rx_R = (hh->id & CMX_BUFF_MASK);
+                       dsp->rx_W = (dsp->rx_R + dsp->cmx_delay)
+                               & CMX_BUFF_MASK;
+               } else {
+                       dsp->rx_R = 0;
+                       dsp->rx_W = dsp->cmx_delay;
+               }
+               memset(dsp->rx_buff, dsp_silence, sizeof(dsp->rx_buff));
+       }
+       /* if we have reached double delay, jump back to middle */
+       if (dsp->cmx_delay)
+               if (((dsp->rx_W - dsp->rx_R) & CMX_BUFF_MASK) >=
+                   (dsp->cmx_delay << 1)) {
+                       if (dsp_debug & DEBUG_DSP_CMX)
+                               printk(KERN_DEBUG
+                                   "cmx_receive(dsp=%lx): OVERRUN (because "
+                                   "twice the delay is reached), adjusting "
+                                   "read pointer! (inst %s)\n",
+                                   (u_long)dsp, dsp->name);
+               /* flush buffer */
+               if (dsp->features.unordered) {
+                       dsp->rx_R = (hh->id & CMX_BUFF_MASK);
+                       dsp->rx_W = (dsp->rx_R + dsp->cmx_delay)
+                               & CMX_BUFF_MASK;
+               } else {
+                       dsp->rx_R = 0;
+                       dsp->rx_W = dsp->cmx_delay;
+               }
+               memset(dsp->rx_buff, dsp_silence, sizeof(dsp->rx_buff));
+       }
+
+       /* show where to write */
+#ifdef CMX_DEBUG
+       printk(KERN_DEBUG
+           "cmx_receive(dsp=%lx): rx_R(dsp)=%05x rx_W(dsp)=%05x len=%d %s\n",
+           (u_long)dsp, dsp->rx_R, dsp->rx_W, len, dsp->name);
+#endif
+
+       /* write data into rx_buffer */
+       p = skb->data;
+       d = dsp->rx_buff;
+       w = dsp->rx_W;
+       i = 0;
+       ii = len;
+       while (i < ii) {
+               d[w++ & CMX_BUFF_MASK] = *p++;
+               i++;
+       }
+
+       /* increase write-pointer */
+       dsp->rx_W = ((dsp->rx_W+len) & CMX_BUFF_MASK);
+}
+
+
+/*
+ * send (mixed) audio data to card and control jitter
+ */
+static void
+dsp_cmx_send_member(struct dsp *dsp, int len, s32 *c, int members)
+{
+       struct dsp_conf *conf = dsp->conf;
+       struct dsp *member, *other;
+       register s32 sample;
+       u8 *d, *p, *q, *o_q;
+       struct sk_buff *nskb, *txskb;
+       int r, rr, t, tt, o_r, o_rr;
+       int preload = 0;
+       struct mISDNhead *hh, *thh;
+
+       /* don't process if: */
+       if (!dsp->b_active) { /* if not active */
+               dsp->last_tx = 0;
+               return;
+       }
+       if (dsp->pcm_slot_tx >= 0 && /* connected to pcm slot */
+           dsp->tx_R == dsp->tx_W && /* AND no tx-data */
+           !(dsp->tone.tone && dsp->tone.software)) { /* AND not soft tones */
+               dsp->last_tx = 0;
+               return;
+       }
+
+#ifdef CMX_DEBUG
+       printk(KERN_DEBUG
+           "SEND members=%d dsp=%s, conf=%p, rx_R=%05x rx_W=%05x\n",
+           members, dsp->name, conf, dsp->rx_R, dsp->rx_W);
+#endif
+
+       /* preload if we have delay set */
+       if (dsp->cmx_delay && !dsp->last_tx) {
+               preload = len;
+               if (preload < 128)
+                       preload = 128;
+       }
+
+       /* PREPARE RESULT */
+       nskb = mI_alloc_skb(len + preload, GFP_ATOMIC);
+       if (!nskb) {
+               printk(KERN_ERR
+                   "FATAL ERROR in mISDN_dsp.o: cannot alloc %d bytes\n",
+                   len + preload);
+               return;
+       }
+       hh = mISDN_HEAD_P(nskb);
+       hh->prim = PH_DATA_REQ;
+       hh->id = 0;
+       dsp->last_tx = 1;
+
+       /* set pointers, indexes and stuff */
+       member = dsp;
+       p = dsp->tx_buff; /* transmit data */
+       q = dsp->rx_buff; /* received data */
+       d = skb_put(nskb, preload + len); /* result */
+       t = dsp->tx_R; /* tx-pointers */
+       tt = dsp->tx_W;
+       r = dsp->rx_R; /* rx-pointers */
+       rr = (r + len) & CMX_BUFF_MASK;
+
+       /* preload with silence, if required */
+       if (preload) {
+               memset(d, dsp_silence, preload);
+               d += preload;
+       }
+
+       /* PROCESS TONES/TX-DATA ONLY */
+       if (dsp->tone.tone && dsp->tone.software) {
+               /* -> copy tone */
+               dsp_tone_copy(dsp, d, len);
+               dsp->tx_R = 0; /* clear tx buffer */
+               dsp->tx_W = 0;
+               goto send_packet;
+       }
+       /* if we have tx-data but do not use mixing */
+       if (!dsp->tx_mix && t != tt) {
+               /* -> send tx-data and continue when not enough */
+#ifdef CMX_TX_DEBUG
+       sprintf(debugbuf, "TX sending (%04x-%04x)%p: ", t, tt, p);
+#endif
+               while (r != rr && t != tt) {
+#ifdef CMX_TX_DEBUG
+                       if (strlen(debugbuf) < 48)
+                           sprintf(debugbuf+strlen(debugbuf), " %02x", p[t]);
+#endif
+                       *d++ = p[t]; /* write tx_buff */
+                       t = (t+1) & CMX_BUFF_MASK;
+                       r = (r+1) & CMX_BUFF_MASK;
+               }
+               if (r == rr) {
+                       dsp->tx_R = t;
+#ifdef CMX_TX_DEBUG
+       printk(KERN_DEBUG "%s\n", debugbuf);
+#endif
+                       goto send_packet;
+               }
+       }
+#ifdef CMX_TX_DEBUG
+       printk(KERN_DEBUG "%s\n", debugbuf);
+#endif
+
+       /* PROCESS DATA (one member / no conf) */
+       if (!conf || members <= 1) {
+               /* -> if echo is NOT enabled */
+               if (!dsp->echo) {
+                       /* -> send tx-data if available or use 0-volume */
+                       while (r != rr && t != tt) {
+                               *d++ = p[t]; /* write tx_buff */
+                               t = (t+1) & CMX_BUFF_MASK;
+                               r = (r+1) & CMX_BUFF_MASK;
+                       }
+                       if (r != rr)
+                               memset(d, dsp_silence, (rr-r)&CMX_BUFF_MASK);
+               /* -> if echo is enabled */
+               } else {
+                       /*
+                        * -> mix tx-data with echo if available,
+                        * or use echo only
+                        */
+                       while (r != rr && t != tt) {
+                               *d++ = dsp_audio_mix_law[(p[t]<<8)|q[r]];
+                               t = (t+1) & CMX_BUFF_MASK;
+                               r = (r+1) & CMX_BUFF_MASK;
+                       }
+                       while (r != rr) {
+                               *d++ = q[r]; /* echo */
+                               r = (r+1) & CMX_BUFF_MASK;
+                       }
+               }
+               dsp->tx_R = t;
+               goto send_packet;
+       }
+       /* PROCESS DATA (two members) */
+#ifdef CMX_CONF_DEBUG
+       if (0) {
+#else
+       if (members == 2) {
+#endif
+               /* "other" becomes other party */
+               other = (list_entry(conf->mlist.next,
+                   struct dsp_conf_member, list))->dsp;
+               if (other == member)
+                       other = (list_entry(conf->mlist.prev,
+                           struct dsp_conf_member, list))->dsp;
+               o_q = other->rx_buff; /* received data */
+               o_rr = (other->rx_R + len) & CMX_BUFF_MASK;
+                       /* end of rx-pointer */
+               o_r = (o_rr - rr + r) & CMX_BUFF_MASK;
+                       /* start rx-pointer at current read position*/
+               /* -> if echo is NOT enabled */
+               if (!dsp->echo) {
+                       /*
+                        * -> copy other member's rx-data,
+                        * if tx-data is available, mix
+                        */
+                       while (o_r != o_rr && t != tt) {
+                               *d++ = dsp_audio_mix_law[(p[t]<<8)|o_q[o_r]];
+                               t = (t+1) & CMX_BUFF_MASK;
+                               o_r = (o_r+1) & CMX_BUFF_MASK;
+                       }
+                       while (o_r != o_rr) {
+                               *d++ = o_q[o_r];
+                               o_r = (o_r+1) & CMX_BUFF_MASK;
+                       }
+               /* -> if echo is enabled */
+               } else {
+                       /*
+                        * -> mix other member's rx-data with echo,
+                        * if tx-data is available, mix
+                        */
+                       while (r != rr && t != tt) {
+                               sample = dsp_audio_law_to_s32[p[t]] +
+                                   dsp_audio_law_to_s32[q[r]] +
+                                   dsp_audio_law_to_s32[o_q[o_r]];
+                               if (sample < -32768)
+                                       sample = -32768;
+                               else if (sample > 32767)
+                                       sample = 32767;
+                               *d++ = dsp_audio_s16_to_law[sample & 0xffff];
+                                   /* tx-data + rx_data + echo */
+                               t = (t+1) & CMX_BUFF_MASK;
+                               r = (r+1) & CMX_BUFF_MASK;
+                               o_r = (o_r+1) & CMX_BUFF_MASK;
+                       }
+                       while (r != rr) {
+                               *d++ = dsp_audio_mix_law[(q[r]<<8)|o_q[o_r]];
+                               r = (r+1) & CMX_BUFF_MASK;
+                               o_r = (o_r+1) & CMX_BUFF_MASK;
+                       }
+               }
+               dsp->tx_R = t;
+               goto send_packet;
+       }
+#ifdef DSP_NEVER_DEFINED
+       }
+#endif
+       /* PROCESS DATA (three or more members) */
+       /* -> if echo is NOT enabled */
+       if (!dsp->echo) {
+               /*
+                * -> substract rx-data from conf-data,
+                * if tx-data is available, mix
+                */
+               while (r != rr && t != tt) {
+                       sample = dsp_audio_law_to_s32[p[t]] + *c++ -
+                           dsp_audio_law_to_s32[q[r]];
+                       if (sample < -32768)
+                               sample = -32768;
+                       else if (sample > 32767)
+                               sample = 32767;
+                       *d++ = dsp_audio_s16_to_law[sample & 0xffff];
+                           /* conf-rx+tx */
+                       r = (r+1) & CMX_BUFF_MASK;
+                       t = (t+1) & CMX_BUFF_MASK;
+               }
+               while (r != rr) {
+                       sample = *c++ - dsp_audio_law_to_s32[q[r]];
+                       if (sample < -32768)
+                               sample = -32768;
+                       else if (sample > 32767)
+                               sample = 32767;
+                       *d++ = dsp_audio_s16_to_law[sample & 0xffff];
+                           /* conf-rx */
+                       r = (r+1) & CMX_BUFF_MASK;
+               }
+       /* -> if echo is enabled */
+       } else {
+               /*
+                * -> encode conf-data, if tx-data
+                * is available, mix
+                */
+               while (r != rr && t != tt) {
+                       sample = dsp_audio_law_to_s32[p[t]] + *c++;
+                       if (sample < -32768)
+                               sample = -32768;
+                       else if (sample > 32767)
+                               sample = 32767;
+                       *d++ = dsp_audio_s16_to_law[sample & 0xffff];
+                           /* conf(echo)+tx */
+                       t = (t+1) & CMX_BUFF_MASK;
+                       r = (r+1) & CMX_BUFF_MASK;
+               }
+               while (r != rr) {
+                       sample = *c++;
+                       if (sample < -32768)
+                               sample = -32768;
+                       else if (sample > 32767)
+                               sample = 32767;
+                       *d++ = dsp_audio_s16_to_law[sample & 0xffff];
+                           /* conf(echo) */
+                       r = (r+1) & CMX_BUFF_MASK;
+               }
+       }
+       dsp->tx_R = t;
+       goto send_packet;
+
+send_packet:
+       /*
+        * send tx-data if enabled - don't filter,
+        * becuase we want what we send, not what we filtered
+        */
+       if (dsp->tx_data) {
+               /* PREPARE RESULT */
+               txskb = mI_alloc_skb(len, GFP_ATOMIC);
+               if (!txskb) {
+                       printk(KERN_ERR
+                           "FATAL ERROR in mISDN_dsp.o: "
+                           "cannot alloc %d bytes\n", len);
+               } else {
+                       thh = mISDN_HEAD_P(txskb);
+                       thh->prim = DL_DATA_REQ;
+                       thh->id = 0;
+                       memcpy(skb_put(txskb, len), nskb->data+preload, len);
+                       /* queue (trigger later) */
+                       skb_queue_tail(&dsp->sendq, txskb);
+               }
+       }
+       /* adjust volume */
+       if (dsp->tx_volume)
+               dsp_change_volume(nskb, dsp->tx_volume);
+       /* pipeline */
+       if (dsp->pipeline.inuse)
+               dsp_pipeline_process_tx(&dsp->pipeline, nskb->data, nskb->len);
+       /* crypt */
+       if (dsp->bf_enable)
+               dsp_bf_encrypt(dsp, nskb->data, nskb->len);
+       /* queue and trigger */
+       skb_queue_tail(&dsp->sendq, nskb);
+       schedule_work(&dsp->workq);
+}
+
+u32    samplecount;
+struct timer_list dsp_spl_tl;
+u32    dsp_spl_jiffies; /* calculate the next time to fire */
+u32    dsp_start_jiffies; /* jiffies at the time, the calculation begins */
+struct timeval dsp_start_tv; /* time at start of calculation */
+
+void
+dsp_cmx_send(void *arg)
+{
+       struct dsp_conf *conf;
+       struct dsp_conf_member *member;
+       struct dsp *dsp;
+       int mustmix, members;
+       s32 mixbuffer[MAX_POLL+100], *c;
+       u8 *p, *q;
+       int r, rr;
+       int jittercheck = 0, delay, i;
+       u_long flags;
+       struct timeval tv;
+       u32 elapsed;
+       s16 length;
+
+       /* lock */
+       spin_lock_irqsave(&dsp_lock, flags);
+
+       if (!dsp_start_tv.tv_sec) {
+               do_gettimeofday(&dsp_start_tv);
+               length = dsp_poll;
+       } else {
+               do_gettimeofday(&tv);
+               elapsed = ((tv.tv_sec - dsp_start_tv.tv_sec) * 8000)
+                   + ((s32)(tv.tv_usec / 125) - (dsp_start_tv.tv_usec / 125));
+               dsp_start_tv.tv_sec = tv.tv_sec;
+               dsp_start_tv.tv_usec = tv.tv_usec;
+               length = elapsed;
+       }
+       if (length > MAX_POLL + 100)
+               length = MAX_POLL + 100;
+/* printk(KERN_DEBUG "len=%d dsp_count=0x%x.%04x dsp_poll_diff=0x%x.%04x\n",
+ length, dsp_count >> 16, dsp_count & 0xffff, dsp_poll_diff >> 16,
+ dsp_poll_diff & 0xffff);
+ */
+
+       /*
+        * check if jitter needs to be checked
+        * (this is about every second = 8192 samples)
+        */
+       samplecount += length;
+       if ((samplecount & 8191) < length)
+               jittercheck = 1;
+
+       /* loop all members that do not require conference mixing */
+       list_for_each_entry(dsp, &dsp_ilist, list) {
+               if (dsp->hdlc)
+                       continue;
+               conf = dsp->conf;
+               mustmix = 0;
+               members = 0;
+               if (conf) {
+                       members = count_list_member(&conf->mlist);
+#ifdef CMX_CONF_DEBUG
+                       if (conf->software && members > 1)
+#else
+                       if (conf->software && members > 2)
+#endif
+                               mustmix = 1;
+               }
+
+               /* transmission required */
+               if (!mustmix) {
+                       dsp_cmx_send_member(dsp, length, mixbuffer, members);
+
+                       /*
+                        * unused mixbuffer is given to prevent a
+                        * potential null-pointer-bug
+                        */
+               }
+       }
+
+       /* loop all members that require conference mixing */
+       list_for_each_entry(conf, &conf_ilist, list) {
+               /* count members and check hardware */
+               members = count_list_member(&conf->mlist);
+#ifdef CMX_CONF_DEBUG
+               if (conf->software && members > 1) {
+#else
+               if (conf->software && members > 2) {
+#endif
+                       /* check for hdlc conf */
+                       member = list_entry(conf->mlist.next,
+                               struct dsp_conf_member, list);
+                       if (member->dsp->hdlc)
+                               continue;
+                       /* mix all data */
+                       memset(mixbuffer, 0, length*sizeof(s32));
+                       list_for_each_entry(member, &conf->mlist, list) {
+                               dsp = member->dsp;
+                               /* get range of data to mix */
+                               c = mixbuffer;
+                               q = dsp->rx_buff;
+                               r = dsp->rx_R;
+                               rr = (r + length) & CMX_BUFF_MASK;
+                               /* add member's data */
+                               while (r != rr) {
+                                       *c++ += dsp_audio_law_to_s32[q[r]];
+                                       r = (r+1) & CMX_BUFF_MASK;
+                               }
+                       }
+
+                       /* process each member */
+                       list_for_each_entry(member, &conf->mlist, list) {
+                               /* transmission */
+                               dsp_cmx_send_member(member->dsp, length,
+                                   mixbuffer, members);
+                       }
+               }
+       }
+
+       /* delete rx-data, increment buffers, change pointers */
+       list_for_each_entry(dsp, &dsp_ilist, list) {
+               if (dsp->hdlc)
+                       continue;
+               p = dsp->rx_buff;
+               q = dsp->tx_buff;
+               r = dsp->rx_R;
+               /* move receive pointer when receiving */
+               if (!dsp->rx_is_off) {
+                       rr = (r + length) & CMX_BUFF_MASK;
+                       /* delete rx-data */
+                       while (r != rr) {
+                               p[r] = dsp_silence;
+                               r = (r+1) & CMX_BUFF_MASK;
+                       }
+                       /* increment rx-buffer pointer */
+                       dsp->rx_R = r; /* write incremented read pointer */
+               }
+
+               /* check current rx_delay */
+               delay = (dsp->rx_W-dsp->rx_R) & CMX_BUFF_MASK;
+               if (delay >= CMX_BUFF_HALF)
+                       delay = 0; /* will be the delay before next write */
+               /* check for lower delay */
+               if (delay < dsp->rx_delay[0])
+                       dsp->rx_delay[0] = delay;
+               /* check current tx_delay */
+               delay = (dsp->tx_W-dsp->tx_R) & CMX_BUFF_MASK;
+               if (delay >= CMX_BUFF_HALF)
+                       delay = 0; /* will be the delay before next write */
+               /* check for lower delay */
+               if (delay < dsp->tx_delay[0])
+                       dsp->tx_delay[0] = delay;
+               if (jittercheck) {
+                       /* find the lowest of all rx_delays */
+                       delay = dsp->rx_delay[0];
+                       i = 1;
+                       while (i < MAX_SECONDS_JITTER_CHECK) {
+                               if (delay > dsp->rx_delay[i])
+                                       delay = dsp->rx_delay[i];
+                               i++;
+                       }
+                       /*
+                        * remove rx_delay only if we have delay AND we
+                        * have not preset cmx_delay
+                        */
+                       if (delay && !dsp->cmx_delay) {
+                               if (dsp_debug & DEBUG_DSP_CMX)
+                                       printk(KERN_DEBUG
+                                           "%s lowest rx_delay of %d bytes for"
+                                           " dsp %s are now removed.\n",
+                                           __func__, delay,
+                                           dsp->name);
+                               r = dsp->rx_R;
+                               rr = (r + delay) & CMX_BUFF_MASK;
+                               /* delete rx-data */
+                               while (r != rr) {
+                                       p[r] = dsp_silence;
+                                       r = (r+1) & CMX_BUFF_MASK;
+                               }
+                               /* increment rx-buffer pointer */
+                               dsp->rx_R = r;
+                                   /* write incremented read pointer */
+                       }
+                       /* find the lowest of all tx_delays */
+                       delay = dsp->tx_delay[0];
+                       i = 1;
+                       while (i < MAX_SECONDS_JITTER_CHECK) {
+                               if (delay > dsp->tx_delay[i])
+                                       delay = dsp->tx_delay[i];
+                               i++;
+                       }
+                       /*
+                        * remove delay only if we have delay AND we
+                        * have enabled tx_dejitter
+                        */
+                       if (delay && dsp->tx_dejitter) {
+                               if (dsp_debug & DEBUG_DSP_CMX)
+                                       printk(KERN_DEBUG
+                                           "%s lowest tx_delay of %d bytes for"
+                                           " dsp %s are now removed.\n",
+                                           __func__, delay,
+                                           dsp->name);
+                               r = dsp->tx_R;
+                               rr = (r + delay) & CMX_BUFF_MASK;
+                               /* delete tx-data */
+                               while (r != rr) {
+                                       q[r] = dsp_silence;
+                                       r = (r+1) & CMX_BUFF_MASK;
+                               }
+                               /* increment rx-buffer pointer */
+                               dsp->tx_R = r;
+                                   /* write incremented read pointer */
+                       }
+                       /* scroll up delays */
+                       i = MAX_SECONDS_JITTER_CHECK - 1;
+                       while (i) {
+                               dsp->rx_delay[i] = dsp->rx_delay[i-1];
+                               dsp->tx_delay[i] = dsp->tx_delay[i-1];
+                               i--;
+                       }
+                       dsp->tx_delay[0] = CMX_BUFF_HALF; /* (infinite) delay */
+                       dsp->rx_delay[0] = CMX_BUFF_HALF; /* (infinite) delay */
+               }
+       }
+
+       /* if next event would be in the past ... */
+       if ((s32)(dsp_spl_jiffies+dsp_tics-jiffies) <= 0)
+               dsp_spl_jiffies = jiffies + 1;
+       else
+               dsp_spl_jiffies += dsp_tics;
+
+       dsp_spl_tl.expires = dsp_spl_jiffies;
+       add_timer(&dsp_spl_tl);
+
+       /* unlock */
+       spin_unlock_irqrestore(&dsp_lock, flags);
+}
+
+/*
+ * audio data is transmitted from upper layer to the dsp
+ */
+void
+dsp_cmx_transmit(struct dsp *dsp, struct sk_buff *skb)
+{
+       u_int w, ww;
+       u8 *d, *p;
+       int space; /* todo: , l = skb->len; */
+#ifdef CMX_TX_DEBUG
+       char debugbuf[256] = "";
+#endif
+
+       /* check if there is enough space, and then copy */
+       w = dsp->tx_W;
+       ww = dsp->tx_R;
+       p = dsp->tx_buff;
+       d = skb->data;
+       space = ww-w;
+       if (space <= 0)
+               space += CMX_BUFF_SIZE;
+       /* write-pointer should not overrun nor reach read pointer */
+       if (space-1 < skb->len)
+               /* write to the space we have left */
+               ww = (ww - 1) & CMX_BUFF_MASK;
+       else
+               /* write until all byte are copied */
+               ww = (w + skb->len) & CMX_BUFF_MASK;
+       dsp->tx_W = ww;
+
+       /* show current buffer */
+#ifdef CMX_DEBUG
+       printk(KERN_DEBUG
+           "cmx_transmit(dsp=%lx) %d bytes to 0x%x-0x%x. %s\n",
+           (u_long)dsp, (ww-w)&CMX_BUFF_MASK, w, ww, dsp->name);
+#endif
+
+       /* copy transmit data to tx-buffer */
+#ifdef CMX_TX_DEBUG
+       sprintf(debugbuf, "TX getting (%04x-%04x)%p: ", w, ww, p);
+#endif
+       while (w != ww) {
+#ifdef CMX_TX_DEBUG
+               if (strlen(debugbuf) < 48)
+                       sprintf(debugbuf+strlen(debugbuf), " %02x", *d);
+#endif
+               p[w] = *d++;
+               w = (w+1) & CMX_BUFF_MASK;
+       }
+#ifdef CMX_TX_DEBUG
+       printk(KERN_DEBUG "%s\n", debugbuf);
+#endif
+
+}
+
+/*
+ * hdlc data is received from card and sent to all members.
+ */
+void
+dsp_cmx_hdlc(struct dsp *dsp, struct sk_buff *skb)
+{
+       struct sk_buff *nskb = NULL;
+       struct dsp_conf_member *member;
+       struct mISDNhead *hh;
+
+       /* not if not active */
+       if (!dsp->b_active)
+               return;
+
+       /* check if we have sompen */
+       if (skb->len < 1)
+               return;
+
+       /* no conf */
+       if (!dsp->conf) {
+               /* in case of hardware (echo) */
+               if (dsp->pcm_slot_tx >= 0)
+                       return;
+               if (dsp->echo)
+                       nskb = skb_clone(skb, GFP_ATOMIC);
+                       if (nskb) {
+                               hh = mISDN_HEAD_P(nskb);
+                               hh->prim = PH_DATA_REQ;
+                               hh->id = 0;
+                               skb_queue_tail(&dsp->sendq, nskb);
+                               schedule_work(&dsp->workq);
+                       }
+               return;
+       }
+       /* in case of hardware conference */
+       if (dsp->conf->hardware)
+               return;
+       list_for_each_entry(member, &dsp->conf->mlist, list) {
+               if (dsp->echo || member->dsp != dsp) {
+                       nskb = skb_clone(skb, GFP_ATOMIC);
+                       if (nskb) {
+                               hh = mISDN_HEAD_P(nskb);
+                               hh->prim = PH_DATA_REQ;
+                               hh->id = 0;
+                               skb_queue_tail(&member->dsp->sendq, nskb);
+                               schedule_work(&member->dsp->workq);
+                       }
+               }
+       }
+}
+
+