1 // SPDX-License-Identifier: GPL-2.0-only
3  * AM824 format in Audio and Music Data Transmission Protocol (IEC 61883-6)
6  * Copyright (c) 2015 Takashi Sakamoto <o-takashi@sakamocchi.jp>
11 #include "amdtp-am824.h"
15 /* "Clock-based rate control mode" is just supported. */
42  * amdtp_am824_set_parameters - set stream parameters
46  *                as AM824 multi-bit linear audio
47  * @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels)
58 	struct amdtp_am824 *p = s->protocol;  in amdtp_am824_set_parameters()
64 		return -EINVAL;  in amdtp_am824_set_parameters()
67 		return -EINVAL;  in amdtp_am824_set_parameters()
71 		return -EINVAL;  in amdtp_am824_set_parameters()
76 		return -EINVAL;  in amdtp_am824_set_parameters()
79 	 * In IEC 61883-6, one data block represents one event. In ALSA, one  in amdtp_am824_set_parameters()
93 	if (s->direction == AMDTP_OUT_STREAM)  in amdtp_am824_set_parameters()
94 		s->ctx_data.rx.fdf = AMDTP_FDF_AM824 | s->sfc;  in amdtp_am824_set_parameters()
96 	p->pcm_channels = pcm_channels;  in amdtp_am824_set_parameters()
97 	p->midi_ports = midi_ports;  in amdtp_am824_set_parameters()
101 		p->pcm_positions[i] = i;  in amdtp_am824_set_parameters()
102 	p->midi_position = p->pcm_channels;  in amdtp_am824_set_parameters()
105 	 * We do not know the actual MIDI FIFO size of most devices.  Just  in amdtp_am824_set_parameters()
110 	p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;  in amdtp_am824_set_parameters()
117  * amdtp_am824_set_pcm_position - set an index of data channel for a channel
120  * @index: the index of data channel in an data block
121  * @position: the channel of PCM frame
126 	struct amdtp_am824 *p = s->protocol;  in amdtp_am824_set_pcm_position()
128 	if (index < p->pcm_channels)  in amdtp_am824_set_pcm_position()
129 		p->pcm_positions[index] = position;  in amdtp_am824_set_pcm_position()
134  * amdtp_am824_set_midi_position - set a index of data channel for MIDI
135  *				   conformant data channel
137  * @position: the index of data channel in an data block
142 	struct amdtp_am824 *p = s->protocol;  in amdtp_am824_set_midi_position()
144 	p->midi_position = position;  in amdtp_am824_set_midi_position()
152 	struct amdtp_am824 *p = s->protocol;  in write_pcm_s32()
153 	unsigned int channels = p->pcm_channels;  in write_pcm_s32()
154 	struct snd_pcm_runtime *runtime = pcm->runtime;  in write_pcm_s32()
160 	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;  in write_pcm_s32()
161 	pcm_buffer_pointer %= runtime->buffer_size;  in write_pcm_s32()
163 	src = (void *)runtime->dma_area +  in write_pcm_s32()
165 	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;  in write_pcm_s32()
169 			buffer[p->pcm_positions[c]] =  in write_pcm_s32()
173 		buffer += s->data_block_quadlets;  in write_pcm_s32()
174 		if (--remaining_frames == 0)  in write_pcm_s32()
175 			src = (void *)runtime->dma_area;  in write_pcm_s32()
183 	struct amdtp_am824 *p = s->protocol;  in read_pcm_s32()
184 	unsigned int channels = p->pcm_channels;  in read_pcm_s32()
185 	struct snd_pcm_runtime *runtime = pcm->runtime;  in read_pcm_s32()
191 	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;  in read_pcm_s32()
192 	pcm_buffer_pointer %= runtime->buffer_size;  in read_pcm_s32()
194 	dst  = (void *)runtime->dma_area +  in read_pcm_s32()
196 	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;  in read_pcm_s32()
200 			*dst = be32_to_cpu(buffer[p->pcm_positions[c]]) << 8;  in read_pcm_s32()
203 		buffer += s->data_block_quadlets;  in read_pcm_s32()
204 		if (--remaining_frames == 0)  in read_pcm_s32()
205 			dst = (void *)runtime->dma_area;  in read_pcm_s32()
212 	struct amdtp_am824 *p = s->protocol;  in write_pcm_silence()
213 	unsigned int i, c, channels = p->pcm_channels;  in write_pcm_silence()
217 			buffer[p->pcm_positions[c]] = cpu_to_be32(0x40000000);  in write_pcm_silence()
218 		buffer += s->data_block_quadlets;  in write_pcm_silence()
223  * amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream
237 	/* AM824 in IEC 61883-6 can deliver 24bit data. */  in amdtp_am824_add_pcm_hw_constraints()
243  * amdtp_am824_midi_trigger - start/stop playback/capture with a MIDI device
255 	struct amdtp_am824 *p = s->protocol;  in amdtp_am824_midi_trigger()
257 	if (port < p->midi_ports)  in amdtp_am824_midi_trigger()
258 		WRITE_ONCE(p->midi[port], midi);  in amdtp_am824_midi_trigger()
264  * device has a FIFO, and track how much it is filled.  This values increases
265  * by one whenever we send one byte in a packet, but the FIFO empties at
267  * samples, so the number of bytes that empty out of the FIFO, per packet(!),
274 	struct amdtp_am824 *p = s->protocol;  in midi_ratelimit_per_packet()
277 	used = p->midi_fifo_used[port];  in midi_ratelimit_per_packet()
281 	used -= MIDI_BYTES_PER_SECOND * s->syt_interval;  in midi_ratelimit_per_packet()
283 	p->midi_fifo_used[port] = used;  in midi_ratelimit_per_packet()
285 	return used < p->midi_fifo_limit;  in midi_ratelimit_per_packet()
290 	struct amdtp_am824 *p = s->protocol;  in midi_rate_use_one_byte()
292 	p->midi_fifo_used[port] += amdtp_rate_table[s->sfc];  in midi_rate_use_one_byte()
298 	struct amdtp_am824 *p = s->protocol;  in write_midi_messages()
303 		b = (u8 *)&buffer[p->midi_position];  in write_midi_messages()
308 		    p->midi[port] != NULL &&  in write_midi_messages()
309 		    snd_rawmidi_transmit(p->midi[port], &b[1], 1) == 1) {  in write_midi_messages()
319 		buffer += s->data_block_quadlets;  in write_midi_messages()
326 	struct amdtp_am824 *p = s->protocol;  in read_midi_messages()
327 	int len;  in read_midi_messages()  local
334 		if (!(s->flags & CIP_UNALIGHED_DBC))  in read_midi_messages()
337 		b = (u8 *)&buffer[p->midi_position];  in read_midi_messages()
339 		len = b[0] - 0x80;  in read_midi_messages()
340 		if ((1 <= len) &&  (len <= 3) && (p->midi[port]))  in read_midi_messages()
341 			snd_rawmidi_receive(p->midi[port], b + 1, len);  in read_midi_messages()
343 		buffer += s->data_block_quadlets;  in read_midi_messages()
350 	struct amdtp_am824 *p = s->protocol;  in process_it_ctx_payloads()
355 		__be32 *buf = desc->ctx_payload;  in process_it_ctx_payloads()
356 		unsigned int data_blocks = desc->data_blocks;  in process_it_ctx_payloads()
360 			pcm_frames += data_blocks * s->pcm_frame_multiplier;  in process_it_ctx_payloads()
365 		if (p->midi_ports) {  in process_it_ctx_payloads()
367 					    desc->data_block_counter);  in process_it_ctx_payloads()
377 	struct amdtp_am824 *p = s->protocol;  in process_ir_ctx_payloads()
382 		__be32 *buf = desc->ctx_payload;  in process_ir_ctx_payloads()
383 		unsigned int data_blocks = desc->data_blocks;  in process_ir_ctx_payloads()
387 			pcm_frames += data_blocks * s->pcm_frame_multiplier;  in process_ir_ctx_payloads()
390 		if (p->midi_ports) {  in process_ir_ctx_payloads()
392 					   desc->data_block_counter);  in process_ir_ctx_payloads()
400  * amdtp_am824_init - initialize an AMDTP stream structure to handle AM824
405  * @flags: the details of the streaming protocol consist of cip_flags enumeration-constants.