1/*
2 * amdtp-tascam.c - a part of driver for TASCAM FireWire series
3 *
4 * Copyright (c) 2015 Takashi Sakamoto
5 *
6 * Licensed under the terms of the GNU General Public License, version 2.
7 */
8
9#include <sound/pcm.h>
10#include "tascam.h"
11
12#define AMDTP_FMT_TSCM_TX	0x1e
13#define AMDTP_FMT_TSCM_RX	0x3e
14
15struct amdtp_tscm {
16	unsigned int pcm_channels;
17
18	void (*transfer_samples)(struct amdtp_stream *s,
19				 struct snd_pcm_substream *pcm,
20				 __be32 *buffer, unsigned int frames);
21};
22
23int amdtp_tscm_set_parameters(struct amdtp_stream *s, unsigned int rate)
24{
25	struct amdtp_tscm *p = s->protocol;
26	unsigned int data_channels;
27
28	if (amdtp_stream_running(s))
29		return -EBUSY;
30
31	data_channels = p->pcm_channels;
32
33	/* Packets in in-stream have extra 2 data channels. */
34	if (s->direction == AMDTP_IN_STREAM)
35		data_channels += 2;
36
37	return amdtp_stream_set_parameters(s, rate, data_channels);
38}
39
40static void write_pcm_s32(struct amdtp_stream *s,
41			  struct snd_pcm_substream *pcm,
42			  __be32 *buffer, unsigned int frames)
43{
44	struct amdtp_tscm *p = s->protocol;
45	struct snd_pcm_runtime *runtime = pcm->runtime;
46	unsigned int channels, remaining_frames, i, c;
47	const u32 *src;
48
49	channels = p->pcm_channels;
50	src = (void *)runtime->dma_area +
51			frames_to_bytes(runtime, s->pcm_buffer_pointer);
52	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
53
54	for (i = 0; i < frames; ++i) {
55		for (c = 0; c < channels; ++c) {
56			buffer[c] = cpu_to_be32(*src);
57			src++;
58		}
59		buffer += s->data_block_quadlets;
60		if (--remaining_frames == 0)
61			src = (void *)runtime->dma_area;
62	}
63}
64
65static void write_pcm_s16(struct amdtp_stream *s,
66			  struct snd_pcm_substream *pcm,
67			  __be32 *buffer, unsigned int frames)
68{
69	struct amdtp_tscm *p = s->protocol;
70	struct snd_pcm_runtime *runtime = pcm->runtime;
71	unsigned int channels, remaining_frames, i, c;
72	const u16 *src;
73
74	channels = p->pcm_channels;
75	src = (void *)runtime->dma_area +
76			frames_to_bytes(runtime, s->pcm_buffer_pointer);
77	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
78
79	for (i = 0; i < frames; ++i) {
80		for (c = 0; c < channels; ++c) {
81			buffer[c] = cpu_to_be32(*src << 16);
82			src++;
83		}
84		buffer += s->data_block_quadlets;
85		if (--remaining_frames == 0)
86			src = (void *)runtime->dma_area;
87	}
88}
89
90static void read_pcm_s32(struct amdtp_stream *s,
91			 struct snd_pcm_substream *pcm,
92			 __be32 *buffer, unsigned int frames)
93{
94	struct amdtp_tscm *p = s->protocol;
95	struct snd_pcm_runtime *runtime = pcm->runtime;
96	unsigned int channels, remaining_frames, i, c;
97	u32 *dst;
98
99	channels = p->pcm_channels;
100	dst  = (void *)runtime->dma_area +
101			frames_to_bytes(runtime, s->pcm_buffer_pointer);
102	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
103
104	/* The first data channel is for event counter. */
105	buffer += 1;
106
107	for (i = 0; i < frames; ++i) {
108		for (c = 0; c < channels; ++c) {
109			*dst = be32_to_cpu(buffer[c]);
110			dst++;
111		}
112		buffer += s->data_block_quadlets;
113		if (--remaining_frames == 0)
114			dst = (void *)runtime->dma_area;
115	}
116}
117
118static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer,
119			      unsigned int data_blocks)
120{
121	struct amdtp_tscm *p = s->protocol;
122	unsigned int channels, i, c;
123
124	channels = p->pcm_channels;
125
126	for (i = 0; i < data_blocks; ++i) {
127		for (c = 0; c < channels; ++c)
128			buffer[c] = 0x00000000;
129		buffer += s->data_block_quadlets;
130	}
131}
132
133int amdtp_tscm_add_pcm_hw_constraints(struct amdtp_stream *s,
134				      struct snd_pcm_runtime *runtime)
135{
136	int err;
137
138	/*
139	 * Our implementation allows this protocol to deliver 24 bit sample in
140	 * 32bit data channel.
141	 */
142	err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
143	if (err < 0)
144		return err;
145
146	return amdtp_stream_add_pcm_hw_constraints(s, runtime);
147}
148
149void amdtp_tscm_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format)
150{
151	struct amdtp_tscm *p = s->protocol;
152
153	if (WARN_ON(amdtp_stream_pcm_running(s)))
154		return;
155
156	switch (format) {
157	default:
158		WARN_ON(1);
159		/* fall through */
160	case SNDRV_PCM_FORMAT_S16:
161		if (s->direction == AMDTP_OUT_STREAM) {
162			p->transfer_samples = write_pcm_s16;
163			break;
164		}
165		WARN_ON(1);
166		/* fall through */
167	case SNDRV_PCM_FORMAT_S32:
168		if (s->direction == AMDTP_OUT_STREAM)
169			p->transfer_samples = write_pcm_s32;
170		else
171			p->transfer_samples = read_pcm_s32;
172		break;
173	}
174}
175
176static unsigned int process_tx_data_blocks(struct amdtp_stream *s,
177					   __be32 *buffer,
178					   unsigned int data_blocks,
179					   unsigned int *syt)
180{
181	struct amdtp_tscm *p = (struct amdtp_tscm *)s->protocol;
182	struct snd_pcm_substream *pcm;
183
184	pcm = ACCESS_ONCE(s->pcm);
185	if (data_blocks > 0 && pcm)
186		p->transfer_samples(s, pcm, buffer, data_blocks);
187
188	/* A place holder for control messages. */
189
190	return data_blocks;
191}
192
193static unsigned int process_rx_data_blocks(struct amdtp_stream *s,
194					   __be32 *buffer,
195					   unsigned int data_blocks,
196					   unsigned int *syt)
197{
198	struct amdtp_tscm *p = (struct amdtp_tscm *)s->protocol;
199	struct snd_pcm_substream *pcm;
200
201	/* This field is not used. */
202	*syt = 0x0000;
203
204	pcm = ACCESS_ONCE(s->pcm);
205	if (pcm)
206		p->transfer_samples(s, pcm, buffer, data_blocks);
207	else
208		write_pcm_silence(s, buffer, data_blocks);
209
210	return data_blocks;
211}
212
213int amdtp_tscm_init(struct amdtp_stream *s, struct fw_unit *unit,
214		    enum amdtp_stream_direction dir, unsigned int pcm_channels)
215{
216	amdtp_stream_process_data_blocks_t process_data_blocks;
217	struct amdtp_tscm *p;
218	unsigned int fmt;
219	int err;
220
221	if (dir == AMDTP_IN_STREAM) {
222		fmt = AMDTP_FMT_TSCM_TX;
223		process_data_blocks = process_tx_data_blocks;
224	} else {
225		fmt = AMDTP_FMT_TSCM_RX;
226		process_data_blocks = process_rx_data_blocks;
227	}
228
229	err = amdtp_stream_init(s, unit, dir,
230				CIP_NONBLOCKING | CIP_SKIP_DBC_ZERO_CHECK, fmt,
231				process_data_blocks, sizeof(struct amdtp_tscm));
232	if (err < 0)
233		return 0;
234
235	/* Use fixed value for FDF field. */
236	s->fdf = 0x00;
237
238	/* This protocol uses fixed number of data channels for PCM samples. */
239	p = s->protocol;
240	p->pcm_channels = pcm_channels;
241
242	return 0;
243}
244