Commit | Line | Data |
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5955815e TS |
1 | /* |
2 | * AM824 format in Audio and Music Data Transmission Protocol (IEC 61883-6) | |
3 | * | |
df075fee | 4 | * Copyright (c) Clemens Ladisch <clemens@ladisch.de> |
5955815e TS |
5 | * Copyright (c) 2015 Takashi Sakamoto <o-takashi@sakamocchi.jp> |
6 | * | |
7 | * Licensed under the terms of the GNU General Public License, version 2. | |
8 | */ | |
9 | ||
df075fee TS |
10 | #include <linux/slab.h> |
11 | ||
5955815e TS |
12 | #include "amdtp-am824.h" |
13 | ||
14 | #define CIP_FMT_AM 0x10 | |
15 | ||
51c29fd2 TS |
16 | /* "Clock-based rate control mode" is just supported. */ |
17 | #define AMDTP_FDF_AM824 0x00 | |
18 | ||
df075fee TS |
19 | /* |
20 | * Nominally 3125 bytes/second, but the MIDI port's clock might be | |
21 | * 1% too slow, and the bus clock 100 ppm too fast. | |
22 | */ | |
23 | #define MIDI_BYTES_PER_SECOND 3093 | |
24 | ||
25 | /* | |
26 | * Several devices look only at the first eight data blocks. | |
27 | * In any case, this is more than enough for the MIDI data rate. | |
28 | */ | |
29 | #define MAX_MIDI_RX_BLOCKS 8 | |
30 | ||
31 | struct amdtp_am824 { | |
32 | struct snd_rawmidi_substream *midi[AM824_MAX_CHANNELS_FOR_MIDI * 8]; | |
33 | int midi_fifo_limit; | |
34 | int midi_fifo_used[AM824_MAX_CHANNELS_FOR_MIDI * 8]; | |
35 | unsigned int pcm_channels; | |
36 | unsigned int midi_ports; | |
37 | ||
38 | u8 pcm_positions[AM824_MAX_CHANNELS_FOR_PCM]; | |
39 | u8 midi_position; | |
40 | ||
41 | void (*transfer_samples)(struct amdtp_stream *s, | |
42 | struct snd_pcm_substream *pcm, | |
43 | __be32 *buffer, unsigned int frames); | |
44 | ||
45 | unsigned int frame_multiplier; | |
46 | }; | |
47 | ||
51c29fd2 TS |
48 | /** |
49 | * amdtp_am824_set_parameters - set stream parameters | |
50 | * @s: the AMDTP stream to configure | |
51 | * @rate: the sample rate | |
52 | * @pcm_channels: the number of PCM samples in each data block, to be encoded | |
53 | * as AM824 multi-bit linear audio | |
54 | * @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels) | |
55 | * @double_pcm_frames: one data block transfers two PCM frames | |
56 | * | |
57 | * The parameters must be set before the stream is started, and must not be | |
58 | * changed while the stream is running. | |
59 | */ | |
60 | int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate, | |
61 | unsigned int pcm_channels, | |
62 | unsigned int midi_ports, | |
63 | bool double_pcm_frames) | |
64 | { | |
df075fee TS |
65 | struct amdtp_am824 *p = s->protocol; |
66 | unsigned int midi_channels; | |
67 | unsigned int i; | |
51c29fd2 TS |
68 | int err; |
69 | ||
df075fee TS |
70 | if (amdtp_stream_running(s)) |
71 | return -EINVAL; | |
72 | ||
73 | if (pcm_channels > AM824_MAX_CHANNELS_FOR_PCM) | |
74 | return -EINVAL; | |
75 | ||
76 | midi_channels = DIV_ROUND_UP(midi_ports, 8); | |
77 | if (midi_channels > AM824_MAX_CHANNELS_FOR_MIDI) | |
78 | return -EINVAL; | |
79 | ||
80 | if (WARN_ON(amdtp_stream_running(s)) || | |
81 | WARN_ON(pcm_channels > AM824_MAX_CHANNELS_FOR_PCM) || | |
82 | WARN_ON(midi_channels > AM824_MAX_CHANNELS_FOR_MIDI)) | |
83 | return -EINVAL; | |
84 | ||
85 | err = amdtp_stream_set_parameters(s, rate, | |
86 | pcm_channels + midi_channels); | |
51c29fd2 TS |
87 | if (err < 0) |
88 | return err; | |
89 | ||
90 | s->fdf = AMDTP_FDF_AM824 | s->sfc; | |
91 | ||
df075fee TS |
92 | p->pcm_channels = pcm_channels; |
93 | p->midi_ports = midi_ports; | |
94 | ||
51c29fd2 TS |
95 | /* |
96 | * In IEC 61883-6, one data block represents one event. In ALSA, one | |
97 | * event equals to one PCM frame. But Dice has a quirk at higher | |
98 | * sampling rate to transfer two PCM frames in one data block. | |
99 | */ | |
100 | if (double_pcm_frames) | |
df075fee | 101 | p->frame_multiplier = 2; |
51c29fd2 | 102 | else |
df075fee TS |
103 | p->frame_multiplier = 1; |
104 | ||
105 | /* init the position map for PCM and MIDI channels */ | |
106 | for (i = 0; i < pcm_channels; i++) | |
107 | p->pcm_positions[i] = i; | |
108 | p->midi_position = p->pcm_channels; | |
109 | ||
110 | /* | |
111 | * We do not know the actual MIDI FIFO size of most devices. Just | |
112 | * assume two bytes, i.e., one byte can be received over the bus while | |
113 | * the previous one is transmitted over MIDI. | |
114 | * (The value here is adjusted for midi_ratelimit_per_packet().) | |
115 | */ | |
116 | p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1; | |
51c29fd2 TS |
117 | |
118 | return 0; | |
119 | } | |
120 | EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters); | |
121 | ||
f65be911 TS |
122 | /** |
123 | * amdtp_am824_set_pcm_position - set an index of data channel for a channel | |
124 | * of PCM frame | |
125 | * @s: the AMDTP stream | |
126 | * @index: the index of data channel in an data block | |
127 | * @position: the channel of PCM frame | |
128 | */ | |
129 | void amdtp_am824_set_pcm_position(struct amdtp_stream *s, unsigned int index, | |
130 | unsigned int position) | |
131 | { | |
df075fee TS |
132 | struct amdtp_am824 *p = s->protocol; |
133 | ||
134 | if (index < p->pcm_channels) | |
135 | p->pcm_positions[index] = position; | |
f65be911 TS |
136 | } |
137 | EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_position); | |
138 | ||
139 | /** | |
140 | * amdtp_am824_set_midi_position - set a index of data channel for MIDI | |
141 | * conformant data channel | |
142 | * @s: the AMDTP stream | |
143 | * @position: the index of data channel in an data block | |
144 | */ | |
145 | void amdtp_am824_set_midi_position(struct amdtp_stream *s, | |
146 | unsigned int position) | |
147 | { | |
df075fee TS |
148 | struct amdtp_am824 *p = s->protocol; |
149 | ||
150 | p->midi_position = position; | |
f65be911 TS |
151 | } |
152 | EXPORT_SYMBOL_GPL(amdtp_am824_set_midi_position); | |
153 | ||
df075fee TS |
154 | static void write_pcm_s32(struct amdtp_stream *s, |
155 | struct snd_pcm_substream *pcm, | |
156 | __be32 *buffer, unsigned int frames) | |
157 | { | |
158 | struct amdtp_am824 *p = s->protocol; | |
159 | struct snd_pcm_runtime *runtime = pcm->runtime; | |
160 | unsigned int channels, remaining_frames, i, c; | |
161 | const u32 *src; | |
162 | ||
163 | channels = p->pcm_channels; | |
164 | src = (void *)runtime->dma_area + | |
165 | frames_to_bytes(runtime, s->pcm_buffer_pointer); | |
166 | remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer; | |
167 | ||
168 | for (i = 0; i < frames; ++i) { | |
169 | for (c = 0; c < channels; ++c) { | |
170 | buffer[p->pcm_positions[c]] = | |
171 | cpu_to_be32((*src >> 8) | 0x40000000); | |
172 | src++; | |
173 | } | |
174 | buffer += s->data_block_quadlets; | |
175 | if (--remaining_frames == 0) | |
176 | src = (void *)runtime->dma_area; | |
177 | } | |
178 | } | |
179 | ||
180 | static void write_pcm_s16(struct amdtp_stream *s, | |
181 | struct snd_pcm_substream *pcm, | |
182 | __be32 *buffer, unsigned int frames) | |
183 | { | |
184 | struct amdtp_am824 *p = s->protocol; | |
185 | struct snd_pcm_runtime *runtime = pcm->runtime; | |
186 | unsigned int channels, remaining_frames, i, c; | |
187 | const u16 *src; | |
188 | ||
189 | channels = p->pcm_channels; | |
190 | src = (void *)runtime->dma_area + | |
191 | frames_to_bytes(runtime, s->pcm_buffer_pointer); | |
192 | remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer; | |
193 | ||
194 | for (i = 0; i < frames; ++i) { | |
195 | for (c = 0; c < channels; ++c) { | |
196 | buffer[p->pcm_positions[c]] = | |
197 | cpu_to_be32((*src << 8) | 0x42000000); | |
198 | src++; | |
199 | } | |
200 | buffer += s->data_block_quadlets; | |
201 | if (--remaining_frames == 0) | |
202 | src = (void *)runtime->dma_area; | |
203 | } | |
204 | } | |
205 | ||
206 | static void read_pcm_s32(struct amdtp_stream *s, | |
207 | struct snd_pcm_substream *pcm, | |
208 | __be32 *buffer, unsigned int frames) | |
209 | { | |
210 | struct amdtp_am824 *p = s->protocol; | |
211 | struct snd_pcm_runtime *runtime = pcm->runtime; | |
212 | unsigned int channels, remaining_frames, i, c; | |
213 | u32 *dst; | |
214 | ||
215 | channels = p->pcm_channels; | |
216 | dst = (void *)runtime->dma_area + | |
217 | frames_to_bytes(runtime, s->pcm_buffer_pointer); | |
218 | remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer; | |
219 | ||
220 | for (i = 0; i < frames; ++i) { | |
221 | for (c = 0; c < channels; ++c) { | |
222 | *dst = be32_to_cpu(buffer[p->pcm_positions[c]]) << 8; | |
223 | dst++; | |
224 | } | |
225 | buffer += s->data_block_quadlets; | |
226 | if (--remaining_frames == 0) | |
227 | dst = (void *)runtime->dma_area; | |
228 | } | |
229 | } | |
230 | ||
231 | static void write_pcm_silence(struct amdtp_stream *s, | |
232 | __be32 *buffer, unsigned int frames) | |
233 | { | |
234 | struct amdtp_am824 *p = s->protocol; | |
235 | unsigned int i, c, channels = p->pcm_channels; | |
236 | ||
237 | for (i = 0; i < frames; ++i) { | |
238 | for (c = 0; c < channels; ++c) | |
239 | buffer[p->pcm_positions[c]] = cpu_to_be32(0x40000000); | |
240 | buffer += s->data_block_quadlets; | |
241 | } | |
242 | } | |
243 | ||
244 | /** | |
245 | * amdtp_am824_set_pcm_format - set the PCM format | |
246 | * @s: the AMDTP stream to configure | |
247 | * @format: the format of the ALSA PCM device | |
248 | * | |
249 | * The sample format must be set after the other parameters (rate/PCM channels/ | |
250 | * MIDI) and before the stream is started, and must not be changed while the | |
251 | * stream is running. | |
252 | */ | |
253 | void amdtp_am824_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format) | |
254 | { | |
255 | struct amdtp_am824 *p = s->protocol; | |
256 | ||
257 | if (WARN_ON(amdtp_stream_pcm_running(s))) | |
258 | return; | |
259 | ||
260 | switch (format) { | |
261 | default: | |
262 | WARN_ON(1); | |
263 | /* fall through */ | |
264 | case SNDRV_PCM_FORMAT_S16: | |
265 | if (s->direction == AMDTP_OUT_STREAM) { | |
266 | p->transfer_samples = write_pcm_s16; | |
267 | break; | |
268 | } | |
269 | WARN_ON(1); | |
270 | /* fall through */ | |
271 | case SNDRV_PCM_FORMAT_S32: | |
272 | if (s->direction == AMDTP_OUT_STREAM) | |
273 | p->transfer_samples = write_pcm_s32; | |
274 | else | |
275 | p->transfer_samples = read_pcm_s32; | |
276 | break; | |
277 | } | |
278 | } | |
279 | EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_format); | |
280 | ||
bc8500da TS |
281 | /** |
282 | * amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream | |
283 | * @s: the AMDTP stream for AM824 data block, must be initialized. | |
284 | * @runtime: the PCM substream runtime | |
285 | * | |
286 | */ | |
287 | int amdtp_am824_add_pcm_hw_constraints(struct amdtp_stream *s, | |
288 | struct snd_pcm_runtime *runtime) | |
289 | { | |
290 | int err; | |
291 | ||
292 | err = amdtp_stream_add_pcm_hw_constraints(s, runtime); | |
293 | if (err < 0) | |
294 | return err; | |
295 | ||
296 | /* AM824 in IEC 61883-6 can deliver 24bit data. */ | |
297 | return snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24); | |
298 | } | |
299 | EXPORT_SYMBOL_GPL(amdtp_am824_add_pcm_hw_constraints); | |
300 | ||
03e2a67e TS |
301 | /** |
302 | * amdtp_am824_midi_trigger - start/stop playback/capture with a MIDI device | |
303 | * @s: the AMDTP stream | |
304 | * @port: index of MIDI port | |
305 | * @midi: the MIDI device to be started, or %NULL to stop the current device | |
306 | * | |
307 | * Call this function on a running isochronous stream to enable the actual | |
308 | * transmission of MIDI data. This function should be called from the MIDI | |
309 | * device's .trigger callback. | |
310 | */ | |
311 | void amdtp_am824_midi_trigger(struct amdtp_stream *s, unsigned int port, | |
312 | struct snd_rawmidi_substream *midi) | |
313 | { | |
df075fee TS |
314 | struct amdtp_am824 *p = s->protocol; |
315 | ||
316 | if (port < p->midi_ports) | |
317 | ACCESS_ONCE(p->midi[port]) = midi; | |
03e2a67e TS |
318 | } |
319 | EXPORT_SYMBOL_GPL(amdtp_am824_midi_trigger); | |
320 | ||
df075fee TS |
321 | /* |
322 | * To avoid sending MIDI bytes at too high a rate, assume that the receiving | |
323 | * device has a FIFO, and track how much it is filled. This values increases | |
324 | * by one whenever we send one byte in a packet, but the FIFO empties at | |
325 | * a constant rate independent of our packet rate. One packet has syt_interval | |
326 | * samples, so the number of bytes that empty out of the FIFO, per packet(!), | |
327 | * is MIDI_BYTES_PER_SECOND * syt_interval / sample_rate. To avoid storing | |
328 | * fractional values, the values in midi_fifo_used[] are measured in bytes | |
329 | * multiplied by the sample rate. | |
330 | */ | |
331 | static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port) | |
332 | { | |
333 | struct amdtp_am824 *p = s->protocol; | |
334 | int used; | |
335 | ||
336 | used = p->midi_fifo_used[port]; | |
337 | if (used == 0) /* common shortcut */ | |
338 | return true; | |
339 | ||
340 | used -= MIDI_BYTES_PER_SECOND * s->syt_interval; | |
341 | used = max(used, 0); | |
342 | p->midi_fifo_used[port] = used; | |
343 | ||
344 | return used < p->midi_fifo_limit; | |
345 | } | |
346 | ||
347 | static void midi_rate_use_one_byte(struct amdtp_stream *s, unsigned int port) | |
348 | { | |
349 | struct amdtp_am824 *p = s->protocol; | |
350 | ||
351 | p->midi_fifo_used[port] += amdtp_rate_table[s->sfc]; | |
352 | } | |
353 | ||
354 | static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer, | |
355 | unsigned int frames) | |
356 | { | |
357 | struct amdtp_am824 *p = s->protocol; | |
358 | unsigned int f, port; | |
359 | u8 *b; | |
360 | ||
361 | for (f = 0; f < frames; f++) { | |
362 | b = (u8 *)&buffer[p->midi_position]; | |
363 | ||
364 | port = (s->data_block_counter + f) % 8; | |
365 | if (f < MAX_MIDI_RX_BLOCKS && | |
366 | midi_ratelimit_per_packet(s, port) && | |
367 | p->midi[port] != NULL && | |
368 | snd_rawmidi_transmit(p->midi[port], &b[1], 1) == 1) { | |
369 | midi_rate_use_one_byte(s, port); | |
370 | b[0] = 0x81; | |
371 | } else { | |
372 | b[0] = 0x80; | |
373 | b[1] = 0; | |
374 | } | |
375 | b[2] = 0; | |
376 | b[3] = 0; | |
377 | ||
378 | buffer += s->data_block_quadlets; | |
379 | } | |
380 | } | |
381 | ||
382 | static void read_midi_messages(struct amdtp_stream *s, | |
383 | __be32 *buffer, unsigned int frames) | |
384 | { | |
385 | struct amdtp_am824 *p = s->protocol; | |
386 | unsigned int f, port; | |
387 | int len; | |
388 | u8 *b; | |
389 | ||
390 | for (f = 0; f < frames; f++) { | |
391 | port = (s->data_block_counter + f) % 8; | |
392 | b = (u8 *)&buffer[p->midi_position]; | |
393 | ||
394 | len = b[0] - 0x80; | |
395 | if ((1 <= len) && (len <= 3) && (p->midi[port])) | |
396 | snd_rawmidi_receive(p->midi[port], b + 1, len); | |
397 | ||
398 | buffer += s->data_block_quadlets; | |
399 | } | |
400 | } | |
401 | ||
02e6ef9f | 402 | static unsigned int process_rx_data_blocks(struct amdtp_stream *s, __be32 *buffer, |
403 | unsigned int data_blocks, unsigned int *syt) | |
df075fee TS |
404 | { |
405 | struct amdtp_am824 *p = s->protocol; | |
406 | struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm); | |
407 | unsigned int pcm_frames; | |
408 | ||
409 | if (pcm) { | |
410 | p->transfer_samples(s, pcm, buffer, data_blocks); | |
411 | pcm_frames = data_blocks * p->frame_multiplier; | |
412 | } else { | |
413 | write_pcm_silence(s, buffer, data_blocks); | |
414 | pcm_frames = 0; | |
415 | } | |
416 | ||
417 | if (p->midi_ports) | |
418 | write_midi_messages(s, buffer, data_blocks); | |
419 | ||
420 | return pcm_frames; | |
421 | } | |
422 | ||
02e6ef9f | 423 | static unsigned int process_tx_data_blocks(struct amdtp_stream *s, __be32 *buffer, |
424 | unsigned int data_blocks, unsigned int *syt) | |
df075fee TS |
425 | { |
426 | struct amdtp_am824 *p = s->protocol; | |
427 | struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm); | |
428 | unsigned int pcm_frames; | |
429 | ||
430 | if (pcm) { | |
431 | p->transfer_samples(s, pcm, buffer, data_blocks); | |
432 | pcm_frames = data_blocks * p->frame_multiplier; | |
433 | } else { | |
434 | pcm_frames = 0; | |
435 | } | |
436 | ||
437 | if (p->midi_ports) | |
438 | read_midi_messages(s, buffer, data_blocks); | |
439 | ||
440 | return pcm_frames; | |
441 | } | |
442 | ||
5955815e TS |
443 | /** |
444 | * amdtp_am824_init - initialize an AMDTP stream structure to handle AM824 | |
445 | * data block | |
446 | * @s: the AMDTP stream to initialize | |
447 | * @unit: the target of the stream | |
448 | * @dir: the direction of stream | |
449 | * @flags: the packet transmission method to use | |
450 | */ | |
451 | int amdtp_am824_init(struct amdtp_stream *s, struct fw_unit *unit, | |
452 | enum amdtp_stream_direction dir, enum cip_flags flags) | |
453 | { | |
df075fee TS |
454 | amdtp_stream_process_data_blocks_t process_data_blocks; |
455 | ||
456 | if (dir == AMDTP_IN_STREAM) | |
457 | process_data_blocks = process_tx_data_blocks; | |
458 | else | |
459 | process_data_blocks = process_rx_data_blocks; | |
460 | ||
461 | return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM, | |
462 | process_data_blocks, | |
463 | sizeof(struct amdtp_am824)); | |
5955815e TS |
464 | } |
465 | EXPORT_SYMBOL_GPL(amdtp_am824_init); |