dsp_tones.c

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/*
 * Audio support data for ISDN4Linux.
 *
 * Copyright Andreas Eversberg ([email protected])
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 */

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


#define DATA_S sample_silence
#define SIZE_S (&sizeof_silence)
#define DATA_GA sample_german_all
#define SIZE_GA (&sizeof_german_all)
#define DATA_GO sample_german_old
#define SIZE_GO (&sizeof_german_old)
#define DATA_DT sample_american_dialtone
#define SIZE_DT (&sizeof_american_dialtone)
#define DATA_RI sample_american_ringing
#define SIZE_RI (&sizeof_american_ringing)
#define DATA_BU sample_american_busy
#define SIZE_BU (&sizeof_american_busy)
#define DATA_S1 sample_special1
#define SIZE_S1 (&sizeof_special1)
#define DATA_S2 sample_special2
#define SIZE_S2 (&sizeof_special2)
#define DATA_S3 sample_special3
#define SIZE_S3 (&sizeof_special3)

/***************/
/* tones loops */
/***************/

/* all tones are alaw encoded */
/* the last sample+1 is in phase with the first sample. the error is low */

static u8 sample_german_all[] = {
    0x80, 0xab, 0x81, 0x6d, 0xfd, 0xdd, 0x5d, 0x9d,
    0x4d, 0xd1, 0x89, 0x88, 0xd0, 0x4c, 0x9c, 0x5c,
    0xdc, 0xfc, 0x6c,
    0x80, 0xab, 0x81, 0x6d, 0xfd, 0xdd, 0x5d, 0x9d,
    0x4d, 0xd1, 0x89, 0x88, 0xd0, 0x4c, 0x9c, 0x5c,
    0xdc, 0xfc, 0x6c,
    0x80, 0xab, 0x81, 0x6d, 0xfd, 0xdd, 0x5d, 0x9d,
    0x4d, 0xd1, 0x89, 0x88, 0xd0, 0x4c, 0x9c, 0x5c,
    0xdc, 0xfc, 0x6c,
    0x80, 0xab, 0x81, 0x6d, 0xfd, 0xdd, 0x5d, 0x9d,
    0x4d, 0xd1, 0x89, 0x88, 0xd0, 0x4c, 0x9c, 0x5c,
    0xdc, 0xfc, 0x6c,
};
static u32 sizeof_german_all = sizeof(sample_german_all);

static u8 sample_german_old[] = {
    0xec, 0x68, 0xe1, 0x6d, 0x6d, 0x91, 0x51, 0xed,
    0x6d, 0x01, 0x1e, 0x10, 0x0c, 0x90, 0x60, 0x70,
    0x8c,
    0xec, 0x68, 0xe1, 0x6d, 0x6d, 0x91, 0x51, 0xed,
    0x6d, 0x01, 0x1e, 0x10, 0x0c, 0x90, 0x60, 0x70,
    0x8c,
    0xec, 0x68, 0xe1, 0x6d, 0x6d, 0x91, 0x51, 0xed,
    0x6d, 0x01, 0x1e, 0x10, 0x0c, 0x90, 0x60, 0x70,
    0x8c,
    0xec, 0x68, 0xe1, 0x6d, 0x6d, 0x91, 0x51, 0xed,
    0x6d, 0x01, 0x1e, 0x10, 0x0c, 0x90, 0x60, 0x70,
    0x8c,
};
static u32 sizeof_german_old = sizeof(sample_german_old);

static u8 sample_american_dialtone[] = {
    0x2a, 0x18, 0x90, 0x6c, 0x4c, 0xbc, 0x4c, 0x6c,
    0x10, 0x58, 0x32, 0xb9, 0x31, 0x2d, 0x8d, 0x0d,
    0x8d, 0x2d, 0x31, 0x99, 0x0f, 0x28, 0x60, 0xf0,
    0xd0, 0x50, 0xd0, 0x30, 0x60, 0x08, 0x8e, 0x67,
    0x09, 0x19, 0x21, 0xe1, 0xd9, 0xb9, 0x29, 0x67,
    0x83, 0x02, 0xce, 0xbe, 0xee, 0x1a, 0x1b, 0xef,
    0xbf, 0xcf, 0x03, 0x82, 0x66, 0x28, 0xb8, 0xd8,
    0xe0, 0x20, 0x18, 0x08, 0x66, 0x8f, 0x09, 0x61,
    0x31, 0xd1, 0x51, 0xd1, 0xf1, 0x61, 0x29, 0x0e,
    0x98, 0x30, 0x2c, 0x8c, 0x0c, 0x8c, 0x2c, 0x30,
    0xb8, 0x33, 0x59, 0x11, 0x6d, 0x4d, 0xbd, 0x4d,
    0x6d, 0x91, 0x19,
};
static u32 sizeof_american_dialtone = sizeof(sample_american_dialtone);

static u8 sample_american_ringing[] = {
    0x2a, 0xe0, 0xac, 0x0c, 0xbc, 0x4c, 0x8c, 0x90,
    0x48, 0xc7, 0xc1, 0xed, 0xcd, 0x4d, 0xcd, 0xed,
    0xc1, 0xb7, 0x08, 0x30, 0xec, 0xcc, 0xcc, 0x8c,
    0x10, 0x58, 0x1a, 0x99, 0x71, 0xed, 0x8d, 0x8d,
    0x2d, 0x41, 0x89, 0x9e, 0x20, 0x70, 0x2c, 0xec,
    0x2c, 0x70, 0x20, 0x86, 0x77, 0xe1, 0x31, 0x11,
    0xd1, 0xf1, 0x81, 0x09, 0xa3, 0x56, 0x58, 0x00,
    0x40, 0xc0, 0x60, 0x38, 0x46, 0x43, 0x57, 0x39,
    0xd9, 0x59, 0x99, 0xc9, 0x77, 0x2f, 0x2e, 0xc6,
    0xd6, 0x28, 0xd6, 0x36, 0x26, 0x2e, 0x8a, 0xa3,
    0x43, 0x63, 0x4b, 0x4a, 0x62, 0x42, 0xa2, 0x8b,
    0x2f, 0x27, 0x37, 0xd7, 0x29, 0xd7, 0xc7, 0x2f,
    0x2e, 0x76, 0xc8, 0x98, 0x58, 0xd8, 0x38, 0x56,
    0x42, 0x47, 0x39, 0x61, 0xc1, 0x41, 0x01, 0x59,
    0x57, 0xa2, 0x08, 0x80, 0xf0, 0xd0, 0x10, 0x30,
    0xe0, 0x76, 0x87, 0x21, 0x71, 0x2d, 0xed, 0x2d,
    0x71, 0x21, 0x9f, 0x88, 0x40, 0x2c, 0x8c, 0x8c,
    0xec, 0x70, 0x98, 0x1b, 0x59, 0x11, 0x8d, 0xcd,
    0xcd, 0xed, 0x31, 0x09, 0xb6, 0xc0, 0xec, 0xcc,
    0x4c, 0xcc, 0xec, 0xc0, 0xc6, 0x49, 0x91, 0x8d,
    0x4d, 0xbd, 0x0d, 0xad, 0xe1,
};
static u32 sizeof_american_ringing = sizeof(sample_american_ringing);

static u8 sample_american_busy[] = {
    0x2a, 0x00, 0x6c, 0x4c, 0x4c, 0x6c, 0xb0, 0x66,
    0x99, 0x11, 0x6d, 0x8d, 0x2d, 0x41, 0xd7, 0x96,
    0x60, 0xf0, 0x70, 0x40, 0x58, 0xf6, 0x53, 0x57,
    0x09, 0x89, 0xd7, 0x5f, 0xe3, 0x2a, 0xe3, 0x5f,
    0xd7, 0x89, 0x09, 0x57, 0x53, 0xf6, 0x58, 0x40,
    0x70, 0xf0, 0x60, 0x96, 0xd7, 0x41, 0x2d, 0x8d,
    0x6d, 0x11, 0x99, 0x66, 0xb0, 0x6c, 0x4c, 0x4c,
    0x6c, 0x00, 0x2a, 0x01, 0x6d, 0x4d, 0x4d, 0x6d,
    0xb1, 0x67, 0x98, 0x10, 0x6c, 0x8c, 0x2c, 0x40,
    0xd6, 0x97, 0x61, 0xf1, 0x71, 0x41, 0x59, 0xf7,
    0x52, 0x56, 0x08, 0x88, 0xd6, 0x5e, 0xe2, 0x2a,
    0xe2, 0x5e, 0xd6, 0x88, 0x08, 0x56, 0x52, 0xf7,
    0x59, 0x41, 0x71, 0xf1, 0x61, 0x97, 0xd6, 0x40,
    0x2c, 0x8c, 0x6c, 0x10, 0x98, 0x67, 0xb1, 0x6d,
    0x4d, 0x4d, 0x6d, 0x01,
};
static u32 sizeof_american_busy = sizeof(sample_american_busy);

static u8 sample_special1[] = {
    0x2a, 0x2c, 0xbc, 0x6c, 0xd6, 0x71, 0xbd, 0x0d,
    0xd9, 0x80, 0xcc, 0x4c, 0x40, 0x39, 0x0d, 0xbd,
    0x11, 0x86, 0xec, 0xbc, 0xec, 0x0e, 0x51, 0xbd,
    0x8d, 0x89, 0x30, 0x4c, 0xcc, 0xe0, 0xe1, 0xcd,
    0x4d, 0x31, 0x88, 0x8c, 0xbc, 0x50, 0x0f, 0xed,
    0xbd, 0xed, 0x87, 0x10, 0xbc, 0x0c, 0x38, 0x41,
    0x4d, 0xcd, 0x81, 0xd8, 0x0c, 0xbc, 0x70, 0xd7,
    0x6d, 0xbd, 0x2d,
};
static u32 sizeof_special1 = sizeof(sample_special1);

static u8 sample_special2[] = {
    0x2a, 0xcc, 0x8c, 0xd7, 0x4d, 0x2d, 0x18, 0xbc,
    0x10, 0xc1, 0xbd, 0xc1, 0x10, 0xbc, 0x18, 0x2d,
    0x4d, 0xd7, 0x8c, 0xcc, 0x2a, 0xcd, 0x8d, 0xd6,
    0x4c, 0x2c, 0x19, 0xbd, 0x11, 0xc0, 0xbc, 0xc0,
    0x11, 0xbd, 0x19, 0x2c, 0x4c, 0xd6, 0x8d, 0xcd,
    0x2a, 0xcc, 0x8c, 0xd7, 0x4d, 0x2d, 0x18, 0xbc,
    0x10, 0xc1, 0xbd, 0xc1, 0x10, 0xbc, 0x18, 0x2d,
    0x4d, 0xd7, 0x8c, 0xcc, 0x2a, 0xcd, 0x8d, 0xd6,
    0x4c, 0x2c, 0x19, 0xbd, 0x11, 0xc0, 0xbc, 0xc0,
    0x11, 0xbd, 0x19, 0x2c, 0x4c, 0xd6, 0x8d, 0xcd,
};
static u32 sizeof_special2 = sizeof(sample_special2);

static u8 sample_special3[] = {
    0x2a, 0xbc, 0x18, 0xcd, 0x11, 0x2c, 0x8c, 0xc1,
    0x4d, 0xd6, 0xbc, 0xd6, 0x4d, 0xc1, 0x8c, 0x2c,
    0x11, 0xcd, 0x18, 0xbc, 0x2a, 0xbd, 0x19, 0xcc,
    0x10, 0x2d, 0x8d, 0xc0, 0x4c, 0xd7, 0xbd, 0xd7,
    0x4c, 0xc0, 0x8d, 0x2d, 0x10, 0xcc, 0x19, 0xbd,
    0x2a, 0xbc, 0x18, 0xcd, 0x11, 0x2c, 0x8c, 0xc1,
    0x4d, 0xd6, 0xbc, 0xd6, 0x4d, 0xc1, 0x8c, 0x2c,
    0x11, 0xcd, 0x18, 0xbc, 0x2a, 0xbd, 0x19, 0xcc,
    0x10, 0x2d, 0x8d, 0xc0, 0x4c, 0xd7, 0xbd, 0xd7,
    0x4c, 0xc0, 0x8d, 0x2d, 0x10, 0xcc, 0x19, 0xbd,
};
static u32 sizeof_special3 = sizeof(sample_special3);

static u8 sample_silence[] = {
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
    0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a,
};
static u32 sizeof_silence = sizeof(sample_silence);

struct tones_samples {
    u32 *len;
    u8 *data;
};
static struct
tones_samples samples[] = {
    {&sizeof_german_all, sample_german_all},
    {&sizeof_german_old, sample_german_old},
    {&sizeof_american_dialtone, sample_american_dialtone},
    {&sizeof_american_ringing, sample_american_ringing},
    {&sizeof_american_busy, sample_american_busy},
    {&sizeof_special1, sample_special1},
    {&sizeof_special2, sample_special2},
    {&sizeof_special3, sample_special3},
    {NULL, NULL},
};

/***********************************
 * generate ulaw from alaw samples *
 ***********************************/

void
dsp_audio_generate_ulaw_samples(void)
{
    int i, j;

    i = 0;
    while (samples[i].len) {
        j = 0;
        while (j < (*samples[i].len)) {
            samples[i].data[j] =
                dsp_audio_alaw_to_ulaw[samples[i].data[j]];
            j++;
        }
        i++;
    }
}


/****************************
 * tone sequence definition *
 ****************************/

static struct pattern {
    int tone;
    u8 *data[10];
    u32 *siz[10];
    u32 seq[10];
} pattern[] = {
    {TONE_GERMAN_DIALTONE,
     {DATA_GA, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GA, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {1900, 0, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_OLDDIALTONE,
     {DATA_GO, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GO, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {1998, 0, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_AMERICAN_DIALTONE,
     {DATA_DT, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_DT, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {8000, 0, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_DIALPBX,
     {DATA_GA, DATA_S, DATA_GA, DATA_S, DATA_GA, DATA_S, NULL, NULL, NULL,
      NULL},
     {SIZE_GA, SIZE_S, SIZE_GA, SIZE_S, SIZE_GA, SIZE_S, NULL, NULL, NULL,
      NULL},
     {2000, 2000, 2000, 2000, 2000, 12000, 0, 0, 0, 0} },

    {TONE_GERMAN_OLDDIALPBX,
     {DATA_GO, DATA_S, DATA_GO, DATA_S, DATA_GO, DATA_S, NULL, NULL, NULL,
      NULL},
     {SIZE_GO, SIZE_S, SIZE_GO, SIZE_S, SIZE_GO, SIZE_S, NULL, NULL, NULL,
      NULL},
     {2000, 2000, 2000, 2000, 2000, 12000, 0, 0, 0, 0} },

    {TONE_AMERICAN_DIALPBX,
     {DATA_DT, DATA_S, DATA_DT, DATA_S, DATA_DT, DATA_S, NULL, NULL, NULL,
      NULL},
     {SIZE_DT, SIZE_S, SIZE_DT, SIZE_S, SIZE_DT, SIZE_S, NULL, NULL, NULL,
      NULL},
     {2000, 2000, 2000, 2000, 2000, 12000, 0, 0, 0, 0} },

    {TONE_GERMAN_RINGING,
     {DATA_GA, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GA, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {8000, 32000, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_OLDRINGING,
     {DATA_GO, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GO, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {8000, 40000, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_AMERICAN_RINGING,
     {DATA_RI, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_RI, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {8000, 32000, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_RINGPBX,
     {DATA_GA, DATA_S, DATA_GA, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GA, SIZE_S, SIZE_GA, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {4000, 4000, 4000, 28000, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_OLDRINGPBX,
     {DATA_GO, DATA_S, DATA_GO, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GO, SIZE_S, SIZE_GO, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {4000, 4000, 4000, 28000, 0, 0, 0, 0, 0, 0} },

    {TONE_AMERICAN_RINGPBX,
     {DATA_RI, DATA_S, DATA_RI, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_RI, SIZE_S, SIZE_RI, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {4000, 4000, 4000, 28000, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_BUSY,
     {DATA_GA, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GA, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {4000, 4000, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_OLDBUSY,
     {DATA_GO, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GO, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {1000, 5000, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_AMERICAN_BUSY,
     {DATA_BU, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_BU, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {4000, 4000, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_HANGUP,
     {DATA_GA, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GA, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {4000, 4000, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_OLDHANGUP,
     {DATA_GO, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GO, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {1000, 5000, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_AMERICAN_HANGUP,
     {DATA_DT, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_DT, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {8000, 0, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_SPECIAL_INFO,
     {DATA_S1, DATA_S2, DATA_S3, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_S1, SIZE_S2, SIZE_S3, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {2666, 2666, 2666, 8002, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_GASSENBESETZT,
     {DATA_GA, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GA, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {2000, 2000, 0, 0, 0, 0, 0, 0, 0, 0} },

    {TONE_GERMAN_AUFSCHALTTON,
     {DATA_GO, DATA_S, DATA_GO, DATA_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {SIZE_GO, SIZE_S, SIZE_GO, SIZE_S, NULL, NULL, NULL, NULL, NULL, NULL},
     {1000, 5000, 1000, 17000, 0, 0, 0, 0, 0, 0} },

    {0,
     {NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
     {0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
};

/******************
 * copy tone data *
 ******************/

/* an sk_buff is generated from the number of samples needed.
 * the count will be changed and may begin from 0 each pattern period.
 * the clue is to precalculate the pointers and legths to use only one
 * memcpy per function call, or two memcpy if the tone sequence changes.
 *
 * pattern - the type of the pattern
 * count - the sample from the beginning of the pattern (phase)
 * len - the number of bytes
 *
 * return - the sk_buff with the sample
 *
 * if tones has finished (e.g. knocking tone), dsp->tones is turned off
 */
void dsp_tone_copy(struct dsp *dsp, u8 *data, int len)
{
    int index, count, start, num;
    struct pattern *pat;
    struct dsp_tone *tone = &dsp->tone;

    /* if we have no tone, we copy silence */
    if (!tone->tone) {
        memset(data, dsp_silence, len);
        return;
    }

    /* process pattern */
    pat = (struct pattern *)tone->pattern;
    /* points to the current pattern */
    index = tone->index; /* gives current sequence index */
    count = tone->count; /* gives current sample */

    /* copy sample */
    while (len) {
        /* find sample to start with */
        while (42) {
            /* wrap around */
            if (!pat->seq[index]) {
                count = 0;
                index = 0;
            }
            /* check if we are currently playing this tone */
            if (count < pat->seq[index])
                break;
            if (dsp_debug & DEBUG_DSP_TONE)
                printk(KERN_DEBUG "%s: reaching next sequence "
                       "(index=%d)\n", __func__, index);
            count -= pat->seq[index];
            index++;
        }
        /* calculate start and number of samples */
        start = count % (*(pat->siz[index]));
        num = len;
        if (num + count > pat->seq[index])
            num = pat->seq[index] - count;
        if (num + start > (*(pat->siz[index])))
            num = (*(pat->siz[index])) - start;
        /* copy memory */
        memcpy(data, pat->data[index] + start, num);
        /* reduce length */
        data += num;
        count += num;
        len -= num;
    }
    tone->index = index;
    tone->count = count;

    /* return sk_buff */
    return;
}


/*******************************
 * send HW message to hfc card *
 *******************************/

static void
dsp_tone_hw_message(struct dsp *dsp, u8 *sample, int len)
{
    struct sk_buff *nskb;

    /* unlocking is not required, because we don't expect a response */
    nskb = _alloc_mISDN_skb(PH_CONTROL_REQ,
                (len) ? HFC_SPL_LOOP_ON : HFC_SPL_LOOP_OFF, len, sample,
                GFP_ATOMIC);
    if (nskb) {
        if (dsp->ch.peer) {
            if (dsp->ch.recv(dsp->ch.peer, nskb))
                dev_kfree_skb(nskb);
        } else
            dev_kfree_skb(nskb);
    }
}


/*****************
 * timer expires *
 *****************/
void
dsp_tone_timeout(void *arg)
{
    struct dsp *dsp = arg;
    struct dsp_tone *tone = &dsp->tone;
    struct pattern *pat = (struct pattern *)tone->pattern;
    int index = tone->index;

    if (!tone->tone)
        return;

    index++;
    if (!pat->seq[index])
        index = 0;
    tone->index = index;

    /* set next tone */
    if (pat->data[index] == DATA_S)
        dsp_tone_hw_message(dsp, NULL, 0);
    else
        dsp_tone_hw_message(dsp, pat->data[index], *(pat->siz[index]));
    /* set timer */
    init_timer(&tone->tl);
    tone->tl.expires = jiffies + (pat->seq[index] * HZ) / 8000;
    add_timer(&tone->tl);
}


/********************
 * set/release tone *
 ********************/

/*
 * tones are relaized by streaming or by special loop commands if supported
 * by hardware. when hardware is used, the patterns will be controlled by
 * timers.
 */
int
dsp_tone(struct dsp *dsp, int tone)
{
    struct pattern *pat;
    int i;
    struct dsp_tone *tonet = &dsp->tone;

    tonet->software = 0;
    tonet->hardware = 0;

    /* we turn off the tone */
    if (!tone) {
        if (dsp->features.hfc_loops && timer_pending(&tonet->tl))
            del_timer(&tonet->tl);
        if (dsp->features.hfc_loops)
            dsp_tone_hw_message(dsp, NULL, 0);
        tonet->tone = 0;
        return 0;
    }

    pat = NULL;
    i = 0;
    while (pattern[i].tone) {
        if (pattern[i].tone == tone) {
            pat = &pattern[i];
            break;
        }
        i++;
    }
    if (!pat) {
        printk(KERN_WARNING "dsp: given tone 0x%x is invalid\n", tone);
        return -EINVAL;
    }
    if (dsp_debug & DEBUG_DSP_TONE)
        printk(KERN_DEBUG "%s: now starting tone %d (index=%d)\n",
               __func__, tone, 0);
    tonet->tone = tone;
    tonet->pattern = pat;
    tonet->index = 0;
    tonet->count = 0;

    if (dsp->features.hfc_loops) {
        tonet->hardware = 1;
        /* set first tone */
        dsp_tone_hw_message(dsp, pat->data[0], *(pat->siz[0]));
        /* set timer */
        if (timer_pending(&tonet->tl))
            del_timer(&tonet->tl);
        init_timer(&tonet->tl);
        tonet->tl.expires = jiffies + (pat->seq[0] * HZ) / 8000;
        add_timer(&tonet->tl);
    } else {
        tonet->software = 1;
    }

    return 0;
}