fft_common.h

// SPDX-License-Identifier: BSD-3-Clause
//
// Copyright(c) 2025 Intel Corporation. All rights reserved.
//
// Author: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

#ifndef __SOF_FFT_COMMON_H__
#define __SOF_FFT_COMMON_H__

#if CONFIG_MATH_FFT_COLD_TWIDDLE_FACTORS
#define SOF_MATH_FFT_COLD_RODATA __cold_rodata
#else
#define SOF_MATH_FFT_COLD_RODATA
#endif

/**
 * fft_plan_common_new() - Common FFT prepare function
 * @param mod: Pointer to module
 * @param inb: Buffer to use for complex input data
 * @param outb: Buffer to use for complex output data
 * @param size: Size of FFT as number of bins
 * @param bits: World length of FFT. Currently only 32 is supported.
 * @return Pointer to FFT plan
 */
struct fft_plan *fft_plan_common_new(struct processing_module *mod, void *inb,
				     void *outb, uint32_t size, int bits);

/**
 * fft_plan_init_bit_reverse - Configures a bit reversal lookup vector
 * @param bit_reverse_idx: Pointer to array to store bit reverse lookup
 * @param size: Size of FFT
 * @param len: Power of two value equals FFT size
 */
void fft_plan_init_bit_reverse(uint16_t *bit_reverse_idx, int size, int len);

/**
 * fft_plan_allocate_twiddle - Allocates memory for twiddle factors
 * @param mod: pointer to module
 * @param size: size of FFT
 * @param bits: word length of FFT, 32 or 16
 * @return Pointer to allocated memory
 */
void *fft_plan_allocate_twiddle(struct processing_module *mod, int size, int bits);

/**
 * fft_plan_init_twiddle - sets up a decimated and re-arranged twiddle factors tabled
 * @param twiddle: pointer to destination twiddle factors
 * @param size: size of FFT
 * @param bits: word length of FFT, 32 or 16
 */
void fft_plan_init_twiddle(void *twiddle, int size, int bits);

#endif /* __SOF_FFT_COMMON_H__ */