summaryrefslogtreecommitdiffstats
path: root/sound/firewire/digi00x/amdtp-dot.c
blob: b02a5e8cad448c40368b9396dc1c0890c91a3a42 (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
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
/*
 * amdtp-dot.c - a part of driver for Digidesign Digi 002/003 family
 *
 * Copyright (c) 2014-2015 Takashi Sakamoto
 * Copyright (C) 2012 Robin Gareus <robin@gareus.org>
 * Copyright (C) 2012 Damien Zammit <damien@zamaudio.com>
 *
 * Licensed under the terms of the GNU General Public License, version 2.
 */

#include <sound/pcm.h>
#include "digi00x.h"

#define CIP_FMT_AM		0x10

/* 'Clock-based rate control mode' is just supported. */
#define AMDTP_FDF_AM824		0x00

/*
 * Nominally 3125 bytes/second, but the MIDI port's clock might be
 * 1% too slow, and the bus clock 100 ppm too fast.
 */
#define MIDI_BYTES_PER_SECOND	3093

/*
 * Several devices look only at the first eight data blocks.
 * In any case, this is more than enough for the MIDI data rate.
 */
#define MAX_MIDI_RX_BLOCKS	8

/*
 * The double-oh-three algorithm was discovered by Robin Gareus and Damien
 * Zammit in 2012, with reverse-engineering for Digi 003 Rack.
 */
struct dot_state {
	u8 carry;
	u8 idx;
	unsigned int off;
};

struct amdtp_dot {
	unsigned int pcm_channels;
	struct dot_state state;

	unsigned int midi_ports;
	/* 2 = MAX(DOT_MIDI_IN_PORTS, DOT_MIDI_OUT_PORTS) */
	struct snd_rawmidi_substream *midi[2];
	int midi_fifo_used[2];
	int midi_fifo_limit;

	void (*transfer_samples)(struct amdtp_stream *s,
				 struct snd_pcm_substream *pcm,
				 __be32 *buffer, unsigned int frames);
};

/*
 * double-oh-three look up table
 *
 * @param idx index byte (audio-sample data) 0x00..0xff
 * @param off channel offset shift
 * @return salt to XOR with given data
 */
#define BYTE_PER_SAMPLE (4)
#define MAGIC_DOT_BYTE (2)
#define MAGIC_BYTE_OFF(x) (((x) * BYTE_PER_SAMPLE) + MAGIC_DOT_BYTE)
static const u8 dot_scrt(const u8 idx, const unsigned int off)
{
	/*
	 * the length of the added pattern only depends on the lower nibble
	 * of the last non-zero data
	 */
	static const u8 len[16] = {0, 1, 3, 5, 7, 9, 11, 13, 14,
				   12, 10, 8, 6, 4, 2, 0};

	/*
	 * the lower nibble of the salt. Interleaved sequence.
	 * this is walked backwards according to len[]
	 */
	static const u8 nib[15] = {0x8, 0x7, 0x9, 0x6, 0xa, 0x5, 0xb, 0x4,
				   0xc, 0x3, 0xd, 0x2, 0xe, 0x1, 0xf};

	/* circular list for the salt's hi nibble. */
	static const u8 hir[15] = {0x0, 0x6, 0xf, 0x8, 0x7, 0x5, 0x3, 0x4,
				   0xc, 0xd, 0xe, 0x1, 0x2, 0xb, 0xa};

	/*
	 * start offset for upper nibble mapping.
	 * note: 9 is /special/. In the case where the high nibble == 0x9,
	 * hir[] is not used and - coincidentally - the salt's hi nibble is
	 * 0x09 regardless of the offset.
	 */
	static const u8 hio[16] = {0, 11, 12, 6, 7, 5, 1, 4,
				   3, 0x00, 14, 13, 8, 9, 10, 2};

	const u8 ln = idx & 0xf;
	const u8 hn = (idx >> 4) & 0xf;
	const u8 hr = (hn == 0x9) ? 0x9 : hir[(hio[hn] + off) % 15];

	if (len[ln] < off)
		return 0x00;

	return ((nib[14 + off - len[ln]]) | (hr << 4));
}

static void dot_encode_step(struct dot_state *state, __be32 *const buffer)
{
	u8 * const data = (u8 *) buffer;

	if (data[MAGIC_DOT_BYTE] != 0x00) {
		state->off = 0;
		state->idx = data[MAGIC_DOT_BYTE] ^ state->carry;
	}
	data[MAGIC_DOT_BYTE] ^= state->carry;
	state->carry = dot_scrt(state->idx, ++(state->off));
}

int amdtp_dot_set_parameters(struct amdtp_stream *s, unsigned int rate,
			     unsigned int pcm_channels)
{
	struct amdtp_dot *p = s->protocol;
	int err;

	if (amdtp_stream_running(s))
		return -EBUSY;

	/*
	 * A first data channel is for MIDI conformant data channel, the rest is
	 * Multi Bit Linear Audio data channel.
	 */
	err = amdtp_stream_set_parameters(s, rate, pcm_channels + 1);
	if (err < 0)
		return err;

	s->fdf = AMDTP_FDF_AM824 | s->sfc;

	p->pcm_channels = pcm_channels;

	if (s->direction == AMDTP_IN_STREAM)
		p->midi_ports = DOT_MIDI_IN_PORTS;
	else
		p->midi_ports = DOT_MIDI_OUT_PORTS;

	/*
	 * We do not know the actual MIDI FIFO size of most devices.  Just
	 * assume two bytes, i.e., one byte can be received over the bus while
	 * the previous one is transmitted over MIDI.
	 * (The value here is adjusted for midi_ratelimit_per_packet().)
	 */
	p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;

	return 0;
}

static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
			  __be32 *buffer, unsigned int frames)
{
	struct amdtp_dot *p = s->protocol;
	struct snd_pcm_runtime *runtime = pcm->runtime;
	unsigned int channels, remaining_frames, i, c;
	const u32 *src;

	channels = p->pcm_channels;
	src = (void *)runtime->dma_area +
			frames_to_bytes(runtime, s->pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;

	buffer++;
	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			buffer[c] = cpu_to_be32((*src >> 8) | 0x40000000);
			dot_encode_step(&p->state, &buffer[c]);
			src++;
		}
		buffer += s->data_block_quadlets;
		if (--remaining_frames == 0)
			src = (void *)runtime->dma_area;
	}
}

static void write_pcm_s16(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
			  __be32 *buffer, unsigned int frames)
{
	struct amdtp_dot *p = s->protocol;
	struct snd_pcm_runtime *runtime = pcm->runtime;
	unsigned int channels, remaining_frames, i, c;
	const u16 *src;

	channels = p->pcm_channels;
	src = (void *)runtime->dma_area +
			frames_to_bytes(runtime, s->pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;

	buffer++;
	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			buffer[c] = cpu_to_be32((*src << 8) | 0x40000000);
			dot_encode_step(&p->state, &buffer[c]);
			src++;
		}
		buffer += s->data_block_quadlets;
		if (--remaining_frames == 0)
			src = (void *)runtime->dma_area;
	}
}

static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
			 __be32 *buffer, unsigned int frames)
{
	struct amdtp_dot *p = s->protocol;
	struct snd_pcm_runtime *runtime = pcm->runtime;
	unsigned int channels, remaining_frames, i, c;
	u32 *dst;

	channels = p->pcm_channels;
	dst  = (void *)runtime->dma_area +
			frames_to_bytes(runtime, s->pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;

	buffer++;
	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			*dst = be32_to_cpu(buffer[c]) << 8;
			dst++;
		}
		buffer += s->data_block_quadlets;
		if (--remaining_frames == 0)
			dst = (void *)runtime->dma_area;
	}
}

static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer,
			      unsigned int data_blocks)
{
	struct amdtp_dot *p = s->protocol;
	unsigned int channels, i, c;

	channels = p->pcm_channels;

	buffer++;
	for (i = 0; i < data_blocks; ++i) {
		for (c = 0; c < channels; ++c)
			buffer[c] = cpu_to_be32(0x40000000);
		buffer += s->data_block_quadlets;
	}
}

static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
{
	struct amdtp_dot *p = s->protocol;
	int used;

	used = p->midi_fifo_used[port];
	if (used == 0)
		return true;

	used -= MIDI_BYTES_PER_SECOND * s->syt_interval;
	used = max(used, 0);
	p->midi_fifo_used[port] = used;

	return used < p->midi_fifo_limit;
}

static inline void midi_use_bytes(struct amdtp_stream *s,
				  unsigned int port, unsigned int count)
{
	struct amdtp_dot *p = s->protocol;

	p->midi_fifo_used[port] += amdtp_rate_table[s->sfc] * count;
}

static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer,
				unsigned int data_blocks)
{
	struct amdtp_dot *p = s->protocol;
	unsigned int f, port;
	int len;
	u8 *b;

	for (f = 0; f < data_blocks; f++) {
		port = (s->data_block_counter + f) % 8;
		b = (u8 *)&buffer[0];

		len = 0;
		if (port < p->midi_ports &&
		    midi_ratelimit_per_packet(s, port) &&
		    p->midi[port] != NULL)
			len = snd_rawmidi_transmit(p->midi[port], b + 1, 2);

		if (len > 0) {
			b[3] = (0x10 << port) | len;
			midi_use_bytes(s, port, len);
		} else {
			b[1] = 0;
			b[2] = 0;
			b[3] = 0;
		}
		b[0] = 0x80;

		buffer += s->data_block_quadlets;
	}
}

static void read_midi_messages(struct amdtp_stream *s, __be32 *buffer,
			       unsigned int data_blocks)
{
	struct amdtp_dot *p = s->protocol;
	unsigned int f, port, len;
	u8 *b;

	for (f = 0; f < data_blocks; f++) {
		b = (u8 *)&buffer[0];
		port = b[3] >> 4;
		len = b[3] & 0x0f;

		if (port < p->midi_ports && p->midi[port] && len > 0)
			snd_rawmidi_receive(p->midi[port], b + 1, len);

		buffer += s->data_block_quadlets;
	}
}

int amdtp_dot_add_pcm_hw_constraints(struct amdtp_stream *s,
				     struct snd_pcm_runtime *runtime)
{
	int err;

	/* This protocol delivers 24 bit data in 32bit data channel. */
	err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
	if (err < 0)
		return err;

	return amdtp_stream_add_pcm_hw_constraints(s, runtime);
}

void amdtp_dot_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format)
{
	struct amdtp_dot *p = s->protocol;

	if (WARN_ON(amdtp_stream_pcm_running(s)))
		return;

	switch (format) {
	default:
		WARN_ON(1);
		/* fall through */
	case SNDRV_PCM_FORMAT_S16:
		if (s->direction == AMDTP_OUT_STREAM) {
			p->transfer_samples = write_pcm_s16;
			break;
		}
		WARN_ON(1);
		/* fall through */
	case SNDRV_PCM_FORMAT_S32:
		if (s->direction == AMDTP_OUT_STREAM)
			p->transfer_samples = write_pcm_s32;
		else
			p->transfer_samples = read_pcm_s32;
		break;
	}
}

void amdtp_dot_midi_trigger(struct amdtp_stream *s, unsigned int port,
			  struct snd_rawmidi_substream *midi)
{
	struct amdtp_dot *p = s->protocol;

	if (port < p->midi_ports)
		ACCESS_ONCE(p->midi[port]) = midi;
}

static unsigned int process_tx_data_blocks(struct amdtp_stream *s,
					   __be32 *buffer,
					   unsigned int data_blocks,
					   unsigned int *syt)
{
	struct amdtp_dot *p = (struct amdtp_dot *)s->protocol;
	struct snd_pcm_substream *pcm;
	unsigned int pcm_frames;

	pcm = ACCESS_ONCE(s->pcm);
	if (pcm) {
		p->transfer_samples(s, pcm, buffer, data_blocks);
		pcm_frames = data_blocks;
	} else {
		pcm_frames = 0;
	}

	read_midi_messages(s, buffer, data_blocks);

	return pcm_frames;
}

static unsigned int process_rx_data_blocks(struct amdtp_stream *s,
					   __be32 *buffer,
					   unsigned int data_blocks,
					   unsigned int *syt)
{
	struct amdtp_dot *p = (struct amdtp_dot *)s->protocol;
	struct snd_pcm_substream *pcm;
	unsigned int pcm_frames;

	pcm = ACCESS_ONCE(s->pcm);
	if (pcm) {
		p->transfer_samples(s, pcm, buffer, data_blocks);
		pcm_frames = data_blocks;
	} else {
		write_pcm_silence(s, buffer, data_blocks);
		pcm_frames = 0;
	}

	write_midi_messages(s, buffer, data_blocks);

	return pcm_frames;
}

int amdtp_dot_init(struct amdtp_stream *s, struct fw_unit *unit,
		 enum amdtp_stream_direction dir)
{
	amdtp_stream_process_data_blocks_t process_data_blocks;
	enum cip_flags flags;

	/* Use different mode between incoming/outgoing. */
	if (dir == AMDTP_IN_STREAM) {
		flags = CIP_NONBLOCKING | CIP_SKIP_INIT_DBC_CHECK;
		process_data_blocks = process_tx_data_blocks;
	} else {
		flags = CIP_BLOCKING;
		process_data_blocks = process_rx_data_blocks;
	}

	return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
				 process_data_blocks, sizeof(struct amdtp_dot));
}

void amdtp_dot_reset(struct amdtp_stream *s)
{
	struct amdtp_dot *p = s->protocol;

	p->state.carry = 0x00;
	p->state.idx = 0x00;
	p->state.off = 0;
}