1 // SPDX-License-Identifier: GPL-2.0-or-later
9 #include "cx88-reg.h"
27  * based on the the sampling rate of the audio rds fifo.
38  * for the input of the audio rds fifo, and measure it's sampling rate to
62 MODULE_PARM_DESC(dsp_debug, "enable audio dsp debug messages");
77 		return -int_cos(x - INT_PI);  in int_cos()
80 		return -int_cos(INT_PI / 2 - (x % (INT_PI / 2)));  in int_cos()
89 	ret = 32768 - t2 + t4 - t6 + t8;  in int_cos()
108 		s32 s = x[i] + ((s64)coeff * s_prev / 32768) - s_prev2;  in int_goertzel()
114 	tmp = (s64)s_prev2 * s_prev2 + (s64)s_prev * s_prev -  in int_goertzel()
143 		x += (N - 192);  in noise_magnitude()
147 	freq_step = (freq_end - freq_start) / (samples - 1);  in noise_magnitude()
157 static s32 detect_a2_a2m_eiaj(struct cx88_core *core, s16 x[], u32 N)  in detect_a2_a2m_eiaj()  argument
163 	switch (core->tvaudio) {  in detect_a2_a2m_eiaj()
181 		pr_warn("unsupported audio mode %d for %s\n",  in detect_a2_a2m_eiaj()
182 			core->tvaudio, __func__);  in detect_a2_a2m_eiaj()
200 	if (core->tvaudio == WW_EIAJ) {  in detect_a2_a2m_eiaj()
224 static s32 detect_btsc(struct cx88_core *core, s16 x[], u32 N)  in detect_btsc()  argument
237 static s16 *read_rds_samples(struct cx88_core *core, u32 *N)  in read_rds_samples()  argument
243 	unsigned int bpl = srch->fifo_size / AUD_RDS_LINES;  in read_rds_samples()
245 	unsigned int sample_count = spl * (AUD_RDS_LINES - 1);  in read_rds_samples()
247 	u32 current_address = cx_read(srch->ptr1_reg);  in read_rds_samples()
248 	u32 offset = (current_address - srch->fifo_start + bpl);  in read_rds_samples()
253 		current_address - srch->fifo_start, sample_count,  in read_rds_samples()
263 		samples[i] = cx_read(srch->fifo_start + offset);  in read_rds_samples()
272 s32 cx88_dsp_detect_stereo_sap(struct cx88_core *core)  in cx88_dsp_detect_stereo_sap()  argument
278 	/* If audio RDS fifo is disabled, we can't read the samples */  in cx88_dsp_detect_stereo_sap()
284 	/* Wait at least 500 ms after an audio standard change */  in cx88_dsp_detect_stereo_sap()
285 	if (time_before(jiffies, core->last_change + msecs_to_jiffies(500)))  in cx88_dsp_detect_stereo_sap()
288 	samples = read_rds_samples(core, &N);  in cx88_dsp_detect_stereo_sap()
293 	switch (core->tvaudio) {  in cx88_dsp_detect_stereo_sap()
298 		ret = detect_a2_a2m_eiaj(core, samples, N);  in cx88_dsp_detect_stereo_sap()
301 		ret = detect_btsc(core, samples, N);  in cx88_dsp_detect_stereo_sap()