patch-2.0.36 linux/drivers/isdn/isdn_audio.c

• Lines: 129
• Date: Sun Nov 15 10:32:59 1998
• Orig file: v2.0.35/linux/drivers/isdn/isdn_audio.c
• Orig date: Mon Aug 4 17:34:00 1997

diff -u --recursive --new-file v2.0.35/linux/drivers/isdn/isdn_audio.c linux/drivers/isdn/isdn_audio.c
@@ -1,9 +1,10 @@
-/* $Id: isdn_audio.c,v 1.8 1997/03/02 14:29:16 fritz Exp $
+/* $Id: isdn_audio.c,v 1.8.2.2 1998/11/05 22:11:35 fritz Exp $
 
  * Linux ISDN subsystem, audio conversion and compression (linklevel).
  *
- * Copyright 1994,95,96 by Fritz Elfert (fritz@wuemaus.franken.de)
+ * Copyright 1994-1998 by Fritz Elfert (fritz@isdn4linux.de)
  * DTMF code (c) 1996 by Christian Mock (cm@kukuruz.ping.at)
+ * Silence detection (c) 1998 by Armin Schindler (mac@gismo.telekom.de)
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,6 +21,12 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  *
  * $Log: isdn_audio.c,v $
+ * Revision 1.8.2.2  1998/11/05 22:11:35  fritz
+ * Changed mail-address.
+ *
+ * Revision 1.8.2.1  1998/08/22 16:43:04  armin
+ * Added silence detection in audio receive mode (AT+VSD).
+ *
  * Revision 1.8  1997/03/02 14:29:16  fritz
  * More ttyI related cleanup.
  *
@@ -53,7 +60,7 @@
 #include "isdn_audio.h"
 #include "isdn_common.h"
 
-char *isdn_audio_revision = "$Revision: 1.8 $";
+char *isdn_audio_revision = "$Revision: 1.8.2.2 $";
 
 /*
  * Misc. lookup-tables.
@@ -652,4 +659,93 @@
 		}
 		len -= c;
 	}
+}
+
+silence_state *
+isdn_audio_silence_init(silence_state * s)
+{
+        if (!s)
+                s = (silence_state *) kmalloc(sizeof(silence_state), GFP_ATOMIC);
+        if (s) {
+                s->idx = 0;
+                s->state = 0;
+        }
+        return s;
+}
+
+void
+isdn_audio_calc_silence(modem_info * info, unsigned char *buf, int len, int fmt)
+{
+        silence_state *s = info->silence_state;
+        int i;
+        signed char c;
+
+        if ((!s) || (!info->emu.vpar[1])) return;
+
+        for (i = 0; i < len; i++) {
+                if (fmt)
+                    c = isdn_audio_alaw_to_ulaw[*buf++];
+                        else
+                    c = *buf++;
+
+                if (c > 0) c -= 128;
+                c = abs(c);
+
+                if (c > (info->emu.vpar[1] * 4)) {
+                        s->idx = 0;
+                        s->state = 1;
+                } else {
+                        if (s->idx < 210000) s->idx++;
+                }
+        }
+}
+
+void
+isdn_audio_eval_silence(modem_info * info)
+{
+        silence_state *s = info->silence_state;
+        struct sk_buff *skb;
+        unsigned long flags;
+        int di;
+        int ch;
+        char what;
+        char *p;
+
+	if (!s) return;
+        what = ' ';
+        if (s->idx > (info->emu.vpar[2] * 800)) {
+                s->idx = 0;
+                if (!s->state) {        /* silence from beginning of rec */
+                        what = 's';
+                } else {
+                        what = 'q';
+                }
+        }
+                if ((what == 's') || (what == 'q')) {
+                        printk(KERN_DEBUG "ttyI%d: %s\n", info->line,
+                                (what=='s') ? "silence":"quiet");
+                        skb = dev_alloc_skb(2);
+                        p = (char *) skb_put(skb, 2);
+                        p[0] = 0x10;
+                        p[1] = what;
+                        if (skb_headroom(skb) < sizeof(isdn_audio_skb)) {
+                                printk(KERN_WARNING
+                                       "isdn_audio: insufficient skb_headroom, dropping\n");
+				kfree_skb(skb, FREE_READ);
+                                return;
+                        }
+                        ISDN_AUDIO_SKB_DLECOUNT(skb) = 0;
+                        ISDN_AUDIO_SKB_LOCK(skb) = 0;
+                        save_flags(flags);
+                        cli();
+                        di = info->isdn_driver;
+                        ch = info->isdn_channel;
+                        __skb_queue_tail(&dev->drv[di]->rpqueue[ch], skb);
+                        dev->drv[di]->rcvcount[ch] += 2;
+                        restore_flags(flags);
+                        /* Schedule dequeuing */
+                        if ((dev->modempoll) && (info->rcvsched))
+                                isdn_timer_ctrl(ISDN_TIMER_MODEMREAD, 1);
+                        wake_up_interruptible(&dev->drv[di]->rcv_waitq[ch]);
+                }
 }