Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 154 insertions, 0 deletions

diff --git a/drivers/misc/echo/fir.h b/drivers/misc/echo/fir.h
new file mode 100644
index 000000000..4d0821025
--- /dev/null
+++ b/drivers/misc/echo/fir.h
@@ -0,0 +1,154 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * 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.
+ */
+
+#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;
+}
+
+static inline void fir16_flush(struct fir16_state_t *fir)
+{
+	memset(fir->history, 0, fir->taps * sizeof(int16_t));
+}
+
+static inline void fir16_free(struct fir16_state_t *fir)
+{
+	kfree(fir->history);
+}
+
+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);
+}
+
+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;
+}
+
+static inline void fir32_flush(struct fir32_state_t *fir)
+{
+	memset(fir->history, 0, fir->taps * sizeof(int16_t));
+}
+
+static inline void fir32_free(struct fir32_state_t *fir)
+{
+	kfree(fir->history);
+}
+
+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);
+}
+
+#endif