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 | ||
df075fee TS |
41 | unsigned int frame_multiplier; |
42 | }; | |
43 | ||
51c29fd2 TS |
44 | /** |
45 | * amdtp_am824_set_parameters - set stream parameters | |
46 | * @s: the AMDTP stream to configure | |
47 | * @rate: the sample rate | |
48 | * @pcm_channels: the number of PCM samples in each data block, to be encoded | |
49 | * as AM824 multi-bit linear audio | |
50 | * @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels) | |
51 | * @double_pcm_frames: one data block transfers two PCM frames | |
52 | * | |
53 | * The parameters must be set before the stream is started, and must not be | |
54 | * changed while the stream is running. | |
55 | */ | |
56 | int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate, | |
57 | unsigned int pcm_channels, | |
58 | unsigned int midi_ports, | |
59 | bool double_pcm_frames) | |
60 | { | |
df075fee TS |
61 | struct amdtp_am824 *p = s->protocol; |
62 | unsigned int midi_channels; | |
63 | unsigned int i; | |
51c29fd2 TS |
64 | int err; |
65 | ||
df075fee TS |
66 | if (amdtp_stream_running(s)) |
67 | return -EINVAL; | |
68 | ||
69 | if (pcm_channels > AM824_MAX_CHANNELS_FOR_PCM) | |
70 | return -EINVAL; | |
71 | ||
72 | midi_channels = DIV_ROUND_UP(midi_ports, 8); | |
73 | if (midi_channels > AM824_MAX_CHANNELS_FOR_MIDI) | |
74 | return -EINVAL; | |
75 | ||
76 | if (WARN_ON(amdtp_stream_running(s)) || | |
77 | WARN_ON(pcm_channels > AM824_MAX_CHANNELS_FOR_PCM) || | |
78 | WARN_ON(midi_channels > AM824_MAX_CHANNELS_FOR_MIDI)) | |
79 | return -EINVAL; | |
80 | ||
81 | err = amdtp_stream_set_parameters(s, rate, | |
82 | pcm_channels + midi_channels); | |
51c29fd2 TS |
83 | if (err < 0) |
84 | return err; | |
85 | ||
86 | s->fdf = AMDTP_FDF_AM824 | s->sfc; | |
87 | ||
df075fee TS |
88 | p->pcm_channels = pcm_channels; |
89 | p->midi_ports = midi_ports; | |
90 | ||
51c29fd2 TS |
91 | /* |
92 | * In IEC 61883-6, one data block represents one event. In ALSA, one | |
93 | * event equals to one PCM frame. But Dice has a quirk at higher | |
94 | * sampling rate to transfer two PCM frames in one data block. | |
95 | */ | |
96 | if (double_pcm_frames) | |
df075fee | 97 | p->frame_multiplier = 2; |
51c29fd2 | 98 | else |
df075fee TS |
99 | p->frame_multiplier = 1; |
100 | ||
101 | /* init the position map for PCM and MIDI channels */ | |
102 | for (i = 0; i < pcm_channels; i++) | |
103 | p->pcm_positions[i] = i; | |
104 | p->midi_position = p->pcm_channels; | |
105 | ||
106 | /* | |
107 | * We do not know the actual MIDI FIFO size of most devices. Just | |
108 | * assume two bytes, i.e., one byte can be received over the bus while | |
109 | * the previous one is transmitted over MIDI. | |
110 | * (The value here is adjusted for midi_ratelimit_per_packet().) | |
111 | */ | |
112 | p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1; | |
51c29fd2 TS |
113 | |
114 | return 0; | |
115 | } | |
116 | EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters); | |
117 | ||
f65be911 TS |
118 | /** |
119 | * amdtp_am824_set_pcm_position - set an index of data channel for a channel | |
120 | * of PCM frame | |
121 | * @s: the AMDTP stream | |
122 | * @index: the index of data channel in an data block | |
123 | * @position: the channel of PCM frame | |
124 | */ | |
125 | void amdtp_am824_set_pcm_position(struct amdtp_stream *s, unsigned int index, | |
126 | unsigned int position) | |
127 | { | |
df075fee TS |
128 | struct amdtp_am824 *p = s->protocol; |
129 | ||
130 | if (index < p->pcm_channels) | |
131 | p->pcm_positions[index] = position; | |
f65be911 TS |
132 | } |
133 | EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_position); | |
134 | ||
135 | /** | |
136 | * amdtp_am824_set_midi_position - set a index of data channel for MIDI | |
137 | * conformant data channel | |
138 | * @s: the AMDTP stream | |
139 | * @position: the index of data channel in an data block | |
140 | */ | |
141 | void amdtp_am824_set_midi_position(struct amdtp_stream *s, | |
142 | unsigned int position) | |
143 | { | |
df075fee TS |
144 | struct amdtp_am824 *p = s->protocol; |
145 | ||
146 | p->midi_position = position; | |
f65be911 TS |
147 | } |
148 | EXPORT_SYMBOL_GPL(amdtp_am824_set_midi_position); | |
149 | ||
df075fee TS |
150 | static void write_pcm_s32(struct amdtp_stream *s, |
151 | struct snd_pcm_substream *pcm, | |
152 | __be32 *buffer, unsigned int frames) | |
153 | { | |
154 | struct amdtp_am824 *p = s->protocol; | |
155 | struct snd_pcm_runtime *runtime = pcm->runtime; | |
156 | unsigned int channels, remaining_frames, i, c; | |
157 | const u32 *src; | |
158 | ||
159 | channels = p->pcm_channels; | |
160 | src = (void *)runtime->dma_area + | |
161 | frames_to_bytes(runtime, s->pcm_buffer_pointer); | |
162 | remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer; | |
163 | ||
164 | for (i = 0; i < frames; ++i) { | |
165 | for (c = 0; c < channels; ++c) { | |
166 | buffer[p->pcm_positions[c]] = | |
167 | cpu_to_be32((*src >> 8) | 0x40000000); | |
168 | src++; | |
169 | } | |
170 | buffer += s->data_block_quadlets; | |
171 | if (--remaining_frames == 0) | |
172 | src = (void *)runtime->dma_area; | |
173 | } | |
174 | } | |
175 | ||
df075fee TS |
176 | static void read_pcm_s32(struct amdtp_stream *s, |
177 | struct snd_pcm_substream *pcm, | |
178 | __be32 *buffer, unsigned int frames) | |
179 | { | |
180 | struct amdtp_am824 *p = s->protocol; | |
181 | struct snd_pcm_runtime *runtime = pcm->runtime; | |
182 | unsigned int channels, remaining_frames, i, c; | |
183 | u32 *dst; | |
184 | ||
185 | channels = p->pcm_channels; | |
186 | dst = (void *)runtime->dma_area + | |
187 | frames_to_bytes(runtime, s->pcm_buffer_pointer); | |
188 | remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer; | |
189 | ||
190 | for (i = 0; i < frames; ++i) { | |
191 | for (c = 0; c < channels; ++c) { | |
192 | *dst = be32_to_cpu(buffer[p->pcm_positions[c]]) << 8; | |
193 | dst++; | |
194 | } | |
195 | buffer += s->data_block_quadlets; | |
196 | if (--remaining_frames == 0) | |
197 | dst = (void *)runtime->dma_area; | |
198 | } | |
199 | } | |
200 | ||
201 | static void write_pcm_silence(struct amdtp_stream *s, | |
202 | __be32 *buffer, unsigned int frames) | |
203 | { | |
204 | struct amdtp_am824 *p = s->protocol; | |
205 | unsigned int i, c, channels = p->pcm_channels; | |
206 | ||
207 | for (i = 0; i < frames; ++i) { | |
208 | for (c = 0; c < channels; ++c) | |
209 | buffer[p->pcm_positions[c]] = cpu_to_be32(0x40000000); | |
210 | buffer += s->data_block_quadlets; | |
211 | } | |
212 | } | |
213 | ||
bc8500da TS |
214 | /** |
215 | * amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream | |
216 | * @s: the AMDTP stream for AM824 data block, must be initialized. | |
217 | * @runtime: the PCM substream runtime | |
218 | * | |
219 | */ | |
220 | int amdtp_am824_add_pcm_hw_constraints(struct amdtp_stream *s, | |
221 | struct snd_pcm_runtime *runtime) | |
222 | { | |
223 | int err; | |
224 | ||
225 | err = amdtp_stream_add_pcm_hw_constraints(s, runtime); | |
226 | if (err < 0) | |
227 | return err; | |
228 | ||
229 | /* AM824 in IEC 61883-6 can deliver 24bit data. */ | |
230 | return snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24); | |
231 | } | |
232 | EXPORT_SYMBOL_GPL(amdtp_am824_add_pcm_hw_constraints); | |
233 | ||
03e2a67e TS |
234 | /** |
235 | * amdtp_am824_midi_trigger - start/stop playback/capture with a MIDI device | |
236 | * @s: the AMDTP stream | |
237 | * @port: index of MIDI port | |
238 | * @midi: the MIDI device to be started, or %NULL to stop the current device | |
239 | * | |
240 | * Call this function on a running isochronous stream to enable the actual | |
241 | * transmission of MIDI data. This function should be called from the MIDI | |
242 | * device's .trigger callback. | |
243 | */ | |
244 | void amdtp_am824_midi_trigger(struct amdtp_stream *s, unsigned int port, | |
245 | struct snd_rawmidi_substream *midi) | |
246 | { | |
df075fee TS |
247 | struct amdtp_am824 *p = s->protocol; |
248 | ||
249 | if (port < p->midi_ports) | |
250 | ACCESS_ONCE(p->midi[port]) = midi; | |
03e2a67e TS |
251 | } |
252 | EXPORT_SYMBOL_GPL(amdtp_am824_midi_trigger); | |
253 | ||
df075fee TS |
254 | /* |
255 | * To avoid sending MIDI bytes at too high a rate, assume that the receiving | |
256 | * device has a FIFO, and track how much it is filled. This values increases | |
257 | * by one whenever we send one byte in a packet, but the FIFO empties at | |
258 | * a constant rate independent of our packet rate. One packet has syt_interval | |
259 | * samples, so the number of bytes that empty out of the FIFO, per packet(!), | |
260 | * is MIDI_BYTES_PER_SECOND * syt_interval / sample_rate. To avoid storing | |
261 | * fractional values, the values in midi_fifo_used[] are measured in bytes | |
262 | * multiplied by the sample rate. | |
263 | */ | |
264 | static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port) | |
265 | { | |
266 | struct amdtp_am824 *p = s->protocol; | |
267 | int used; | |
268 | ||
269 | used = p->midi_fifo_used[port]; | |
270 | if (used == 0) /* common shortcut */ | |
271 | return true; | |
272 | ||
273 | used -= MIDI_BYTES_PER_SECOND * s->syt_interval; | |
274 | used = max(used, 0); | |
275 | p->midi_fifo_used[port] = used; | |
276 | ||
277 | return used < p->midi_fifo_limit; | |
278 | } | |
279 | ||
280 | static void midi_rate_use_one_byte(struct amdtp_stream *s, unsigned int port) | |
281 | { | |
282 | struct amdtp_am824 *p = s->protocol; | |
283 | ||
284 | p->midi_fifo_used[port] += amdtp_rate_table[s->sfc]; | |
285 | } | |
286 | ||
287 | static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer, | |
288 | unsigned int frames) | |
289 | { | |
290 | struct amdtp_am824 *p = s->protocol; | |
291 | unsigned int f, port; | |
292 | u8 *b; | |
293 | ||
294 | for (f = 0; f < frames; f++) { | |
295 | b = (u8 *)&buffer[p->midi_position]; | |
296 | ||
297 | port = (s->data_block_counter + f) % 8; | |
298 | if (f < MAX_MIDI_RX_BLOCKS && | |
299 | midi_ratelimit_per_packet(s, port) && | |
300 | p->midi[port] != NULL && | |
301 | snd_rawmidi_transmit(p->midi[port], &b[1], 1) == 1) { | |
302 | midi_rate_use_one_byte(s, port); | |
303 | b[0] = 0x81; | |
304 | } else { | |
305 | b[0] = 0x80; | |
306 | b[1] = 0; | |
307 | } | |
308 | b[2] = 0; | |
309 | b[3] = 0; | |
310 | ||
311 | buffer += s->data_block_quadlets; | |
312 | } | |
313 | } | |
314 | ||
315 | static void read_midi_messages(struct amdtp_stream *s, | |
316 | __be32 *buffer, unsigned int frames) | |
317 | { | |
318 | struct amdtp_am824 *p = s->protocol; | |
319 | unsigned int f, port; | |
320 | int len; | |
321 | u8 *b; | |
322 | ||
323 | for (f = 0; f < frames; f++) { | |
324 | port = (s->data_block_counter + f) % 8; | |
325 | b = (u8 *)&buffer[p->midi_position]; | |
326 | ||
327 | len = b[0] - 0x80; | |
328 | if ((1 <= len) && (len <= 3) && (p->midi[port])) | |
329 | snd_rawmidi_receive(p->midi[port], b + 1, len); | |
330 | ||
331 | buffer += s->data_block_quadlets; | |
332 | } | |
333 | } | |
334 | ||
02e6ef9f | 335 | static unsigned int process_rx_data_blocks(struct amdtp_stream *s, __be32 *buffer, |
336 | unsigned int data_blocks, unsigned int *syt) | |
df075fee TS |
337 | { |
338 | struct amdtp_am824 *p = s->protocol; | |
339 | struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm); | |
340 | unsigned int pcm_frames; | |
341 | ||
342 | if (pcm) { | |
a02cb8f8 | 343 | write_pcm_s32(s, pcm, buffer, data_blocks); |
df075fee TS |
344 | pcm_frames = data_blocks * p->frame_multiplier; |
345 | } else { | |
346 | write_pcm_silence(s, buffer, data_blocks); | |
347 | pcm_frames = 0; | |
348 | } | |
349 | ||
350 | if (p->midi_ports) | |
351 | write_midi_messages(s, buffer, data_blocks); | |
352 | ||
353 | return pcm_frames; | |
354 | } | |
355 | ||
02e6ef9f | 356 | static unsigned int process_tx_data_blocks(struct amdtp_stream *s, __be32 *buffer, |
357 | unsigned int data_blocks, unsigned int *syt) | |
df075fee TS |
358 | { |
359 | struct amdtp_am824 *p = s->protocol; | |
360 | struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm); | |
361 | unsigned int pcm_frames; | |
362 | ||
363 | if (pcm) { | |
a02cb8f8 | 364 | read_pcm_s32(s, pcm, buffer, data_blocks); |
df075fee TS |
365 | pcm_frames = data_blocks * p->frame_multiplier; |
366 | } else { | |
367 | pcm_frames = 0; | |
368 | } | |
369 | ||
370 | if (p->midi_ports) | |
371 | read_midi_messages(s, buffer, data_blocks); | |
372 | ||
373 | return pcm_frames; | |
374 | } | |
375 | ||
5955815e TS |
376 | /** |
377 | * amdtp_am824_init - initialize an AMDTP stream structure to handle AM824 | |
378 | * data block | |
379 | * @s: the AMDTP stream to initialize | |
380 | * @unit: the target of the stream | |
381 | * @dir: the direction of stream | |
382 | * @flags: the packet transmission method to use | |
383 | */ | |
384 | int amdtp_am824_init(struct amdtp_stream *s, struct fw_unit *unit, | |
385 | enum amdtp_stream_direction dir, enum cip_flags flags) | |
386 | { | |
df075fee TS |
387 | amdtp_stream_process_data_blocks_t process_data_blocks; |
388 | ||
389 | if (dir == AMDTP_IN_STREAM) | |
390 | process_data_blocks = process_tx_data_blocks; | |
391 | else | |
392 | process_data_blocks = process_rx_data_blocks; | |
393 | ||
394 | return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM, | |
395 | process_data_blocks, | |
396 | sizeof(struct amdtp_am824)); | |
5955815e TS |
397 | } |
398 | EXPORT_SYMBOL_GPL(amdtp_am824_init); |