summaryrefslogtreecommitdiffstats
path: root/drivers/media/pci/cx88/cx88-dsp.c
blob: a9907265ff668a59636ef25e32b3fbe151c4ae77 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
/*
 *
 *  Stereo and SAP detection for cx88
 *
 *  Copyright (c) 2009 Marton Balint <cus@fazekas.hu>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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.
 */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/jiffies.h>
#include <asm/div64.h>

#include "cx88.h"
#include "cx88-reg.h"

#define INT_PI			((s32)(3.141592653589 * 32768.0))

#define compat_remainder(a, b) \
	 ((float)(((s32)((a)*100))%((s32)((b)*100)))/100.0)

#define baseband_freq(carrier, srate, tone) ((s32)( \
	 (compat_remainder(carrier + tone, srate)) / srate * 2 * INT_PI))

/* We calculate the baseband frequencies of the carrier and the pilot tones
 * based on the the sampling rate of the audio rds fifo. */

#define FREQ_A2_CARRIER         baseband_freq(54687.5, 2689.36, 0.0)
#define FREQ_A2_DUAL            baseband_freq(54687.5, 2689.36, 274.1)
#define FREQ_A2_STEREO          baseband_freq(54687.5, 2689.36, 117.5)

/* The frequencies below are from the reference driver. They probably need
 * further adjustments, because they are not tested at all. You may even need
 * to play a bit with the registers of the chip to select the proper signal
 * for the input of the audio rds fifo, and measure it's sampling rate to
 * calculate the proper baseband frequencies... */

#define FREQ_A2M_CARRIER	((s32)(2.114516 * 32768.0))
#define FREQ_A2M_DUAL		((s32)(2.754916 * 32768.0))
#define FREQ_A2M_STEREO		((s32)(2.462326 * 32768.0))

#define FREQ_EIAJ_CARRIER	((s32)(1.963495 * 32768.0)) /* 5pi/8  */
#define FREQ_EIAJ_DUAL		((s32)(2.562118 * 32768.0))
#define FREQ_EIAJ_STEREO	((s32)(2.601053 * 32768.0))

#define FREQ_BTSC_DUAL		((s32)(1.963495 * 32768.0)) /* 5pi/8  */
#define FREQ_BTSC_DUAL_REF	((s32)(1.374446 * 32768.0)) /* 7pi/16 */

#define FREQ_BTSC_SAP		((s32)(2.471532 * 32768.0))
#define FREQ_BTSC_SAP_REF	((s32)(1.730072 * 32768.0))

/* The spectrum of the signal should be empty between these frequencies. */
#define FREQ_NOISE_START	((s32)(0.100000 * 32768.0))
#define FREQ_NOISE_END		((s32)(1.200000 * 32768.0))

static unsigned int dsp_debug;
module_param(dsp_debug, int, 0644);
MODULE_PARM_DESC(dsp_debug, "enable audio dsp debug messages");

#define dprintk(level, fmt, arg...)	if (dsp_debug >= level) \
	printk(KERN_DEBUG "%s/0: " fmt, core->name , ## arg)

static s32 int_cos(u32 x)
{
	u32 t2, t4, t6, t8;
	s32 ret;
	u16 period = x / INT_PI;
	if (period % 2)
		return -int_cos(x - INT_PI);
	x = x % INT_PI;
	if (x > INT_PI/2)
		return -int_cos(INT_PI/2 - (x % (INT_PI/2)));
	/* Now x is between 0 and INT_PI/2.
	 * To calculate cos(x) we use it's Taylor polinom. */
	t2 = x*x/32768/2;
	t4 = t2*x/32768*x/32768/3/4;
	t6 = t4*x/32768*x/32768/5/6;
	t8 = t6*x/32768*x/32768/7/8;
	ret = 32768-t2+t4-t6+t8;
	return ret;
}

static u32 int_goertzel(s16 x[], u32 N, u32 freq)
{
	/* We use the Goertzel algorithm to determine the power of the
	 * given frequency in the signal */
	s32 s_prev = 0;
	s32 s_prev2 = 0;
	s32 coeff = 2*int_cos(freq);
	u32 i;

	u64 tmp;
	u32 divisor;

	for (i = 0; i < N; i++) {
		s32 s = x[i] + ((s64)coeff*s_prev/32768) - s_prev2;
		s_prev2 = s_prev;
		s_prev = s;
	}

	tmp = (s64)s_prev2 * s_prev2 + (s64)s_prev * s_prev -
		      (s64)coeff * s_prev2 * s_prev / 32768;

	/* XXX: N must be low enough so that N*N fits in s32.
	 * Else we need two divisions. */
	divisor = N * N;
	do_div(tmp, divisor);

	return (u32) tmp;
}

static u32 freq_magnitude(s16 x[], u32 N, u32 freq)
{
	u32 sum = int_goertzel(x, N, freq);
	return (u32)int_sqrt(sum);
}

static u32 noise_magnitude(s16 x[], u32 N, u32 freq_start, u32 freq_end)
{
	int i;
	u32 sum = 0;
	u32 freq_step;
	int samples = 5;

	if (N > 192) {
		/* The last 192 samples are enough for noise detection */
		x += (N-192);
		N = 192;
	}

	freq_step = (freq_end - freq_start) / (samples - 1);

	for (i = 0; i < samples; i++) {
		sum += int_goertzel(x, N, freq_start);
		freq_start += freq_step;
	}

	return (u32)int_sqrt(sum / samples);
}

static s32 detect_a2_a2m_eiaj(struct cx88_core *core, s16 x[], u32 N)
{
	s32 carrier, stereo, dual, noise;
	s32 carrier_freq, stereo_freq, dual_freq;
	s32 ret;

	switch (core->tvaudio) {
	case WW_BG:
	case WW_DK:
		carrier_freq = FREQ_A2_CARRIER;
		stereo_freq = FREQ_A2_STEREO;
		dual_freq = FREQ_A2_DUAL;
		break;
	case WW_M:
		carrier_freq = FREQ_A2M_CARRIER;
		stereo_freq = FREQ_A2M_STEREO;
		dual_freq = FREQ_A2M_DUAL;
		break;
	case WW_EIAJ:
		carrier_freq = FREQ_EIAJ_CARRIER;
		stereo_freq = FREQ_EIAJ_STEREO;
		dual_freq = FREQ_EIAJ_DUAL;
		break;
	default:
		printk(KERN_WARNING "%s/0: unsupported audio mode %d for %s\n",
		       core->name, core->tvaudio, __func__);
		return UNSET;
	}

	carrier = freq_magnitude(x, N, carrier_freq);
	stereo  = freq_magnitude(x, N, stereo_freq);
	dual    = freq_magnitude(x, N, dual_freq);
	noise   = noise_magnitude(x, N, FREQ_NOISE_START, FREQ_NOISE_END);

	dprintk(1, "detect a2/a2m/eiaj: carrier=%d, stereo=%d, dual=%d, "
		   "noise=%d\n", carrier, stereo, dual, noise);

	if (stereo > dual)
		ret = V4L2_TUNER_SUB_STEREO;
	else
		ret = V4L2_TUNER_SUB_LANG1 | V4L2_TUNER_SUB_LANG2;

	if (core->tvaudio == WW_EIAJ) {
		/* EIAJ checks may need adjustments */
		if ((carrier > max(stereo, dual)*2) &&
		    (carrier < max(stereo, dual)*6) &&
		    (carrier > 20 && carrier < 200) &&
		    (max(stereo, dual) > min(stereo, dual))) {
			/* For EIAJ the carrier is always present,
			   so we probably don't need noise detection */
			return ret;
		}
	} else {
		if ((carrier > max(stereo, dual)*2) &&
		    (carrier < max(stereo, dual)*8) &&
		    (carrier > 20 && carrier < 200) &&
		    (noise < 10) &&
		    (max(stereo, dual) > min(stereo, dual)*2)) {
			return ret;
		}
	}
	return V4L2_TUNER_SUB_MONO;
}

static s32 detect_btsc(struct cx88_core *core, s16 x[], u32 N)
{
	s32 sap_ref = freq_magnitude(x, N, FREQ_BTSC_SAP_REF);
	s32 sap = freq_magnitude(x, N, FREQ_BTSC_SAP);
	s32 dual_ref = freq_magnitude(x, N, FREQ_BTSC_DUAL_REF);
	s32 dual = freq_magnitude(x, N, FREQ_BTSC_DUAL);
	dprintk(1, "detect btsc: dual_ref=%d, dual=%d, sap_ref=%d, sap=%d"
		   "\n", dual_ref, dual, sap_ref, sap);
	/* FIXME: Currently not supported */
	return UNSET;
}

static s16 *read_rds_samples(struct cx88_core *core, u32 *N)
{
	const struct sram_channel *srch = &cx88_sram_channels[SRAM_CH27];
	s16 *samples;

	unsigned int i;
	unsigned int bpl = srch->fifo_size/AUD_RDS_LINES;
	unsigned int spl = bpl/4;
	unsigned int sample_count = spl*(AUD_RDS_LINES-1);

	u32 current_address = cx_read(srch->ptr1_reg);
	u32 offset = (current_address - srch->fifo_start + bpl);

	dprintk(1, "read RDS samples: current_address=%08x (offset=%08x), "
		"sample_count=%d, aud_intstat=%08x\n", current_address,
		current_address - srch->fifo_start, sample_count,
		cx_read(MO_AUD_INTSTAT));

	samples = kmalloc(sizeof(s16)*sample_count, GFP_KERNEL);
	if (!samples)
		return NULL;

	*N = sample_count;

	for (i = 0; i < sample_count; i++)  {
		offset = offset % (AUD_RDS_LINES*bpl);
		samples[i] = cx_read(srch->fifo_start + offset);
		offset += 4;
	}

	if (dsp_debug >= 2) {
		dprintk(2, "RDS samples dump: ");
		for (i = 0; i < sample_count; i++)
			printk("%hd ", samples[i]);
		printk(".\n");
	}

	return samples;
}

s32 cx88_dsp_detect_stereo_sap(struct cx88_core *core)
{
	s16 *samples;
	u32 N = 0;
	s32 ret = UNSET;

	/* If audio RDS fifo is disabled, we can't read the samples */
	if (!(cx_read(MO_AUD_DMACNTRL) & 0x04))
		return ret;
	if (!(cx_read(AUD_CTL) & EN_FMRADIO_EN_RDS))
		return ret;

	/* Wait at least 500 ms after an audio standard change */
	if (time_before(jiffies, core->last_change + msecs_to_jiffies(500)))
		return ret;

	samples = read_rds_samples(core, &N);

	if (!samples)
		return ret;

	switch (core->tvaudio) {
	case WW_BG:
	case WW_DK:
	case WW_EIAJ:
	case WW_M:
		ret = detect_a2_a2m_eiaj(core, samples, N);
		break;
	case WW_BTSC:
		ret = detect_btsc(core, samples, N);
		break;
	case WW_NONE:
	case WW_I:
	case WW_L:
	case WW_I2SPT:
	case WW_FM:
	case WW_I2SADC:
		break;
	}

	kfree(samples);

	if (UNSET != ret)
		dprintk(1, "stereo/sap detection result:%s%s%s\n",
			   (ret & V4L2_TUNER_SUB_MONO) ? " mono" : "",
			   (ret & V4L2_TUNER_SUB_STEREO) ? " stereo" : "",
			   (ret & V4L2_TUNER_SUB_LANG2) ? " dual" : "");

	return ret;
}
EXPORT_SYMBOL(cx88_dsp_detect_stereo_sap);