Release 4.17 drivers/misc/echo/fir.h
/*
* SpanDSP - a series of DSP components for telephony
*
* fir.h - General telephony FIR routines
*
* Written by Steve Underwood <steveu@coppice.org>
*
* Copyright (C) 2002 Steve Underwood
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#if !defined(_FIR_H_)
#define _FIR_H_
/*
Ideas for improvement:
1/ Rewrite filter for dual MAC inner loop. The issue here is handling
history sample offsets that are 16 bit aligned - the dual MAC needs
32 bit aligmnent. There are some good examples in libbfdsp.
2/ Use the hardware circular buffer facility tohalve memory usage.
3/ Consider using internal memory.
Using less memory might also improve speed as cache misses will be
reduced. A drop in MIPs and memory approaching 50% should be
possible.
The foreground and background filters currenlty use a total of
about 10 MIPs/ch as measured with speedtest.c on a 256 TAP echo
can.
*/
/*
* 16 bit integer FIR descriptor. This defines the working state for a single
* instance of an FIR filter using 16 bit integer coefficients.
*/
struct fir16_state_t {
int taps;
int curr_pos;
const int16_t *coeffs;
int16_t *history;
};
/*
* 32 bit integer FIR descriptor. This defines the working state for a single
* instance of an FIR filter using 32 bit integer coefficients, and filtering
* 16 bit integer data.
*/
struct fir32_state_t {
int taps;
int curr_pos;
const int32_t *coeffs;
int16_t *history;
};
/*
* Floating point FIR descriptor. This defines the working state for a single
* instance of an FIR filter using floating point coefficients and data.
*/
struct fir_float_state_t {
int taps;
int curr_pos;
const float *coeffs;
float *history;
};
static inline const int16_t *fir16_create(struct fir16_state_t *fir,
const int16_t *coeffs, int taps)
{
fir->taps = taps;
fir->curr_pos = taps - 1;
fir->coeffs = coeffs;
fir->history = kcalloc(taps, sizeof(int16_t), GFP_KERNEL);
return fir->history;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rowe | 58 | 92.06% | 1 | 25.00% |
| Pekka J Enberg | 3 | 4.76% | 1 | 25.00% |
| Alexander Beregalov | 1 | 1.59% | 1 | 25.00% |
| J.R. Mauro | 1 | 1.59% | 1 | 25.00% |
| Total | 63 | 100.00% | 4 | 100.00% |
static inline void fir16_flush(struct fir16_state_t *fir)
{
memset(fir->history, 0, fir->taps * sizeof(int16_t));
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rowe | 28 | 93.33% | 1 | 33.33% |
| Alexander Beregalov | 1 | 3.33% | 1 | 33.33% |
| J.R. Mauro | 1 | 3.33% | 1 | 33.33% |
| Total | 30 | 100.00% | 3 | 100.00% |
static inline void fir16_free(struct fir16_state_t *fir)
{
kfree(fir->history);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rowe | 16 | 84.21% | 1 | 25.00% |
| J.R. Mauro | 1 | 5.26% | 1 | 25.00% |
| Alexander Beregalov | 1 | 5.26% | 1 | 25.00% |
| Pekka J Enberg | 1 | 5.26% | 1 | 25.00% |
| Total | 19 | 100.00% | 4 | 100.00% |
static inline int16_t fir16(struct fir16_state_t *fir, int16_t sample)
{
int32_t y;
int i;
int offset1;
int offset2;
fir->history[fir->curr_pos] = sample;
offset2 = fir->curr_pos;
offset1 = fir->taps - offset2;
y = 0;
for (i = fir->taps - 1; i >= offset1; i--)
y += fir->coeffs[i] * fir->history[i - offset1];
for (; i >= 0; i--)
y += fir->coeffs[i] * fir->history[i + offset2];
if (fir->curr_pos <= 0)
fir->curr_pos = fir->taps;
fir->curr_pos--;
return (int16_t) (y >> 15);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rowe | 148 | 98.67% | 1 | 33.33% |
| Alexander Beregalov | 1 | 0.67% | 1 | 33.33% |
| J.R. Mauro | 1 | 0.67% | 1 | 33.33% |
| Total | 150 | 100.00% | 3 | 100.00% |
static inline const int16_t *fir32_create(struct fir32_state_t *fir,
const int32_t *coeffs, int taps)
{
fir->taps = taps;
fir->curr_pos = taps - 1;
fir->coeffs = coeffs;
fir->history = kcalloc(taps, sizeof(int16_t), GFP_KERNEL);
return fir->history;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rowe | 58 | 92.06% | 1 | 25.00% |
| Pekka J Enberg | 3 | 4.76% | 1 | 25.00% |
| Alexander Beregalov | 1 | 1.59% | 1 | 25.00% |
| J.R. Mauro | 1 | 1.59% | 1 | 25.00% |
| Total | 63 | 100.00% | 4 | 100.00% |
static inline void fir32_flush(struct fir32_state_t *fir)
{
memset(fir->history, 0, fir->taps * sizeof(int16_t));
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rowe | 28 | 93.33% | 1 | 33.33% |
| J.R. Mauro | 1 | 3.33% | 1 | 33.33% |
| Alexander Beregalov | 1 | 3.33% | 1 | 33.33% |
| Total | 30 | 100.00% | 3 | 100.00% |
static inline void fir32_free(struct fir32_state_t *fir)
{
kfree(fir->history);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rowe | 16 | 84.21% | 1 | 25.00% |
| Pekka J Enberg | 1 | 5.26% | 1 | 25.00% |
| Alexander Beregalov | 1 | 5.26% | 1 | 25.00% |
| J.R. Mauro | 1 | 5.26% | 1 | 25.00% |
| Total | 19 | 100.00% | 4 | 100.00% |
static inline int16_t fir32(struct fir32_state_t *fir, int16_t sample)
{
int i;
int32_t y;
int offset1;
int offset2;
fir->history[fir->curr_pos] = sample;
offset2 = fir->curr_pos;
offset1 = fir->taps - offset2;
y = 0;
for (i = fir->taps - 1; i >= offset1; i--)
y += fir->coeffs[i] * fir->history[i - offset1];
for (; i >= 0; i--)
y += fir->coeffs[i] * fir->history[i + offset2];
if (fir->curr_pos <= 0)
fir->curr_pos = fir->taps;
fir->curr_pos--;
return (int16_t) (y >> 15);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rowe | 148 | 98.67% | 1 | 33.33% |
| Alexander Beregalov | 1 | 0.67% | 1 | 33.33% |
| J.R. Mauro | 1 | 0.67% | 1 | 33.33% |
| Total | 150 | 100.00% | 3 | 100.00% |
#endif
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rowe | 566 | 94.18% | 1 | 16.67% |
| J.R. Mauro | 14 | 2.33% | 1 | 16.67% |
| Alexander Beregalov | 9 | 1.50% | 1 | 16.67% |
| Pekka J Enberg | 8 | 1.33% | 1 | 16.67% |
| Greg Kroah-Hartman | 3 | 0.50% | 1 | 16.67% |
| Aaron Wu | 1 | 0.17% | 1 | 16.67% |
| Total | 601 | 100.00% | 6 | 100.00% |
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.