1 // SPDX-License-Identifier: GPL-2.0-only
3  * amdtp-dot.c - a part of driver for Digidesign Digi 002/003 family
5  * Copyright (c) 2014-2015 Takashi Sakamoto
15 /* 'Clock-based rate control mode' is just supported. */
34  * The double-oh-three algorithm was discovered by Robin Gareus and Damien
35  * Zammit in 2012, with reverse-engineering for Digi 003 Rack.
53  * double-oh-three look up table
55  * @param idx index byte (audio-sample data) 0x00..0xff
56  * @param off channel offset shift
66 	 * of the last non-zero data  in dot_scrt()
85 	 * hir[] is not used and - coincidentally - the salt's hi nibble is  in dot_scrt()
98 	return ((nib[14 + off - len[ln]]) | (hr << 4));  in dot_scrt()
106 		state->off = 0;  in dot_encode_step()
107 		state->idx = data[MAGIC_DOT_BYTE] ^ state->carry;  in dot_encode_step()
109 	data[MAGIC_DOT_BYTE] ^= state->carry;  in dot_encode_step()
110 	state->carry = dot_scrt(state->idx, ++(state->off));  in dot_encode_step()
116 	struct amdtp_dot *p = s->protocol;  in amdtp_dot_set_parameters()
120 		return -EBUSY;  in amdtp_dot_set_parameters()
123 	 * A first data channel is for MIDI messages, the rest is Multi Bit  in amdtp_dot_set_parameters()
124 	 * Linear Audio data channel.  in amdtp_dot_set_parameters()
130 	s->ctx_data.rx.fdf = AMDTP_FDF_AM824 | s->sfc;  in amdtp_dot_set_parameters()
132 	p->pcm_channels = pcm_channels;  in amdtp_dot_set_parameters()
140 	p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;  in amdtp_dot_set_parameters()
149 	struct amdtp_dot *p = s->protocol;  in write_pcm_s32()
150 	unsigned int channels = p->pcm_channels;  in write_pcm_s32()
151 	struct snd_pcm_runtime *runtime = pcm->runtime;  in write_pcm_s32()
157 	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;  in write_pcm_s32()
158 	pcm_buffer_pointer %= runtime->buffer_size;  in write_pcm_s32()
160 	src = (void *)runtime->dma_area +  in write_pcm_s32()
162 	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;  in write_pcm_s32()
168 			dot_encode_step(&p->state, &buffer[c]);  in write_pcm_s32()
171 		buffer += s->data_block_quadlets;  in write_pcm_s32()
172 		if (--remaining_frames == 0)  in write_pcm_s32()
173 			src = (void *)runtime->dma_area;  in write_pcm_s32()
181 	struct amdtp_dot *p = s->protocol;  in read_pcm_s32()
182 	unsigned int channels = p->pcm_channels;  in read_pcm_s32()
183 	struct snd_pcm_runtime *runtime = pcm->runtime;  in read_pcm_s32()
189 	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;  in read_pcm_s32()
190 	pcm_buffer_pointer %= runtime->buffer_size;  in read_pcm_s32()
192 	dst  = (void *)runtime->dma_area +  in read_pcm_s32()
194 	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;  in read_pcm_s32()
202 		buffer += s->data_block_quadlets;  in read_pcm_s32()
203 		if (--remaining_frames == 0)  in read_pcm_s32()
204 			dst = (void *)runtime->dma_area;  in read_pcm_s32()
211 	struct amdtp_dot *p = s->protocol;  in write_pcm_silence()
214 	channels = p->pcm_channels;  in write_pcm_silence()
220 		buffer += s->data_block_quadlets;  in write_pcm_silence()
226 	struct amdtp_dot *p = s->protocol;  in midi_ratelimit_per_packet()
229 	used = p->midi_fifo_used[port];  in midi_ratelimit_per_packet()
233 	used -= MIDI_BYTES_PER_SECOND * s->syt_interval;  in midi_ratelimit_per_packet()
235 	p->midi_fifo_used[port] = used;  in midi_ratelimit_per_packet()
237 	return used < p->midi_fifo_limit;  in midi_ratelimit_per_packet()
243 	struct amdtp_dot *p = s->protocol;  in midi_use_bytes()
245 	p->midi_fifo_used[port] += amdtp_rate_table[s->sfc] * count;  in midi_use_bytes()
251 	struct amdtp_dot *p = s->protocol;  in write_midi_messages()
263 		    p->midi[port] != NULL)  in write_midi_messages()
264 			len = snd_rawmidi_transmit(p->midi[port], b + 1, 2);  in write_midi_messages()
269 			 * - 0000b: physical MIDI port 1.  in write_midi_messages()
270 			 * - 0010b: physical MIDI port 2.  in write_midi_messages()
271 			 * - 1110b: console MIDI port.  in write_midi_messages()
288 		buffer += s->data_block_quadlets;  in write_midi_messages()
295 	struct amdtp_dot *p = s->protocol;  in read_midi_messages()
306 			 * - 0000b: physical MIDI port 1. Use port 0.  in read_midi_messages()
307 			 * - 1110b: console MIDI port. Use port 2.  in read_midi_messages()
314 			if (port < MAX_MIDI_PORTS && p->midi[port])  in read_midi_messages()
315 				snd_rawmidi_receive(p->midi[port], b + 1, len);  in read_midi_messages()
318 		buffer += s->data_block_quadlets;  in read_midi_messages()
327 	/* This protocol delivers 24 bit data in 32bit data channel. */  in amdtp_dot_add_pcm_hw_constraints()
338 	struct amdtp_dot *p = s->protocol;  in amdtp_dot_midi_trigger()
341 		WRITE_ONCE(p->midi[port], midi);  in amdtp_dot_midi_trigger()
351 		__be32 *buf = desc->ctx_payload;  in process_ir_ctx_payloads()
352 		unsigned int data_blocks = desc->data_blocks;  in process_ir_ctx_payloads()
372 		__be32 *buf = desc->ctx_payload;  in process_it_ctx_payloads()
373 		unsigned int data_blocks = desc->data_blocks;  in process_it_ctx_payloads()
383 				    desc->data_block_counter);  in process_it_ctx_payloads()
407 	struct amdtp_dot *p = s->protocol;  in amdtp_dot_reset()
409 	p->state.carry = 0x00;  in amdtp_dot_reset()
410 	p->state.idx = 0x00;  in amdtp_dot_reset()
411 	p->state.off = 0;  in amdtp_dot_reset()