[linux-2.6-block.git] / sound / firewire / amdtp-am824.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * AM824 format in Audio and Music Data Transmission Protocol (IEC 61883-6)
 *
 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
 * Copyright (c) 2015 Takashi Sakamoto <o-takashi@sakamocchi.jp>
 */

#include <linux/slab.h>

#include "amdtp-am824.h"

#define CIP_FMT_AM		0x10

/* "Clock-based rate control mode" is just supported. */
#define AMDTP_FDF_AM824		0x00

/*
 * Nominally 3125 bytes/second, but the MIDI port's clock might be
 * 1% too slow, and the bus clock 100 ppm too fast.
 */
#define MIDI_BYTES_PER_SECOND	3093

/*
 * Several devices look only at the first eight data blocks.
 * In any case, this is more than enough for the MIDI data rate.
 */
#define MAX_MIDI_RX_BLOCKS	8

struct amdtp_am824 {
	struct snd_rawmidi_substream *midi[AM824_MAX_CHANNELS_FOR_MIDI * 8];
	int midi_fifo_limit;
	int midi_fifo_used[AM824_MAX_CHANNELS_FOR_MIDI * 8];
	unsigned int pcm_channels;
	unsigned int midi_ports;

	u8 pcm_positions[AM824_MAX_CHANNELS_FOR_PCM];
	u8 midi_position;

	unsigned int frame_multiplier;
};

/**
 * amdtp_am824_set_parameters - set stream parameters
 * @s: the AMDTP stream to configure
 * @rate: the sample rate
 * @pcm_channels: the number of PCM samples in each data block, to be encoded
 *                as AM824 multi-bit linear audio
 * @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels)
 * @double_pcm_frames: one data block transfers two PCM frames
 *
 * The parameters must be set before the stream is started, and must not be
 * changed while the stream is running.
 */
int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate,
			       unsigned int pcm_channels,
			       unsigned int midi_ports,
			       bool double_pcm_frames)
{
	struct amdtp_am824 *p = s->protocol;
	unsigned int midi_channels;
	unsigned int i;
	int err;

	if (amdtp_stream_running(s))
		return -EINVAL;

	if (pcm_channels > AM824_MAX_CHANNELS_FOR_PCM)
		return -EINVAL;

	midi_channels = DIV_ROUND_UP(midi_ports, 8);
	if (midi_channels > AM824_MAX_CHANNELS_FOR_MIDI)
		return -EINVAL;

	if (WARN_ON(amdtp_stream_running(s)) ||
	    WARN_ON(pcm_channels > AM824_MAX_CHANNELS_FOR_PCM) ||
	    WARN_ON(midi_channels > AM824_MAX_CHANNELS_FOR_MIDI))
		return -EINVAL;

	err = amdtp_stream_set_parameters(s, rate,
					  pcm_channels + midi_channels);
	if (err < 0)
		return err;

	s->ctx_data.rx.fdf = AMDTP_FDF_AM824 | s->sfc;

	p->pcm_channels = pcm_channels;
	p->midi_ports = midi_ports;

	/*
	 * In IEC 61883-6, one data block represents one event. In ALSA, one
	 * event equals to one PCM frame. But Dice has a quirk at higher
	 * sampling rate to transfer two PCM frames in one data block.
	 */
	if (double_pcm_frames)
		p->frame_multiplier = 2;
	else
		p->frame_multiplier = 1;

	/* init the position map for PCM and MIDI channels */
	for (i = 0; i < pcm_channels; i++)
		p->pcm_positions[i] = i;
	p->midi_position = p->pcm_channels;

	/*
	 * We do not know the actual MIDI FIFO size of most devices.  Just
	 * assume two bytes, i.e., one byte can be received over the bus while
	 * the previous one is transmitted over MIDI.
	 * (The value here is adjusted for midi_ratelimit_per_packet().)
	 */
	p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;

	return 0;
}
EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters);

/**
 * amdtp_am824_set_pcm_position - set an index of data channel for a channel
 *				  of PCM frame
 * @s: the AMDTP stream
 * @index: the index of data channel in an data block
 * @position: the channel of PCM frame
 */
void amdtp_am824_set_pcm_position(struct amdtp_stream *s, unsigned int index,
				 unsigned int position)
{
	struct amdtp_am824 *p = s->protocol;

	if (index < p->pcm_channels)
		p->pcm_positions[index] = position;
}
EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_position);

/**
 * amdtp_am824_set_midi_position - set a index of data channel for MIDI
 *				   conformant data channel
 * @s: the AMDTP stream
 * @position: the index of data channel in an data block
 */
void amdtp_am824_set_midi_position(struct amdtp_stream *s,
				   unsigned int position)
{
	struct amdtp_am824 *p = s->protocol;

	p->midi_position = position;
}
EXPORT_SYMBOL_GPL(amdtp_am824_set_midi_position);

static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
			  __be32 *buffer, unsigned int frames,
			  unsigned int pcm_frames)
{
	struct amdtp_am824 *p = s->protocol;
	unsigned int channels = p->pcm_channels;
	struct snd_pcm_runtime *runtime = pcm->runtime;
	unsigned int pcm_buffer_pointer;
	int remaining_frames;
	const u32 *src;
	int i, c;

	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
	pcm_buffer_pointer %= runtime->buffer_size;

	src = (void *)runtime->dma_area +
				frames_to_bytes(runtime, pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			buffer[p->pcm_positions[c]] =
					cpu_to_be32((*src >> 8) | 0x40000000);
			src++;
		}
		buffer += s->data_block_quadlets;
		if (--remaining_frames == 0)
			src = (void *)runtime->dma_area;
	}
}

static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
			 __be32 *buffer, unsigned int frames,
			 unsigned int pcm_frames)
{
	struct amdtp_am824 *p = s->protocol;
	unsigned int channels = p->pcm_channels;
	struct snd_pcm_runtime *runtime = pcm->runtime;
	unsigned int pcm_buffer_pointer;
	int remaining_frames;
	u32 *dst;
	int i, c;

	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
	pcm_buffer_pointer %= runtime->buffer_size;

	dst  = (void *)runtime->dma_area +
				frames_to_bytes(runtime, pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			*dst = be32_to_cpu(buffer[p->pcm_positions[c]]) << 8;
			dst++;
		}
		buffer += s->data_block_quadlets;
		if (--remaining_frames == 0)
			dst = (void *)runtime->dma_area;
	}
}

static void write_pcm_silence(struct amdtp_stream *s,
			      __be32 *buffer, unsigned int frames)
{
	struct amdtp_am824 *p = s->protocol;
	unsigned int i, c, channels = p->pcm_channels;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c)
			buffer[p->pcm_positions[c]] = cpu_to_be32(0x40000000);
		buffer += s->data_block_quadlets;
	}
}

/**
 * amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream
 * @s:		the AMDTP stream for AM824 data block, must be initialized.
 * @runtime:	the PCM substream runtime
 *
 */
int amdtp_am824_add_pcm_hw_constraints(struct amdtp_stream *s,
				       struct snd_pcm_runtime *runtime)
{
	int err;

	err = amdtp_stream_add_pcm_hw_constraints(s, runtime);
	if (err < 0)
		return err;

	/* AM824 in IEC 61883-6 can deliver 24bit data. */
	return snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
}
EXPORT_SYMBOL_GPL(amdtp_am824_add_pcm_hw_constraints);

/**
 * amdtp_am824_midi_trigger - start/stop playback/capture with a MIDI device
 * @s: the AMDTP stream
 * @port: index of MIDI port
 * @midi: the MIDI device to be started, or %NULL to stop the current device
 *
 * Call this function on a running isochronous stream to enable the actual
 * transmission of MIDI data.  This function should be called from the MIDI
 * device's .trigger callback.
 */
void amdtp_am824_midi_trigger(struct amdtp_stream *s, unsigned int port,
			      struct snd_rawmidi_substream *midi)
{
	struct amdtp_am824 *p = s->protocol;

	if (port < p->midi_ports)
		WRITE_ONCE(p->midi[port], midi);
}
EXPORT_SYMBOL_GPL(amdtp_am824_midi_trigger);

/*
 * To avoid sending MIDI bytes at too high a rate, assume that the receiving
 * device has a FIFO, and track how much it is filled.  This values increases
 * by one whenever we send one byte in a packet, but the FIFO empties at
 * a constant rate independent of our packet rate.  One packet has syt_interval
 * samples, so the number of bytes that empty out of the FIFO, per packet(!),
 * is MIDI_BYTES_PER_SECOND * syt_interval / sample_rate.  To avoid storing
 * fractional values, the values in midi_fifo_used[] are measured in bytes
 * multiplied by the sample rate.
 */
static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
{
	struct amdtp_am824 *p = s->protocol;
	int used;

	used = p->midi_fifo_used[port];
	if (used == 0) /* common shortcut */
		return true;

	used -= MIDI_BYTES_PER_SECOND * s->syt_interval;
	used = max(used, 0);
	p->midi_fifo_used[port] = used;

	return used < p->midi_fifo_limit;
}

static void midi_rate_use_one_byte(struct amdtp_stream *s, unsigned int port)
{
	struct amdtp_am824 *p = s->protocol;

	p->midi_fifo_used[port] += amdtp_rate_table[s->sfc];
}

static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer,
			unsigned int frames, unsigned int data_block_counter)
{
	struct amdtp_am824 *p = s->protocol;
	unsigned int f, port;
	u8 *b;

	for (f = 0; f < frames; f++) {
		b = (u8 *)&buffer[p->midi_position];

		port = (data_block_counter + f) % 8;
		if (f < MAX_MIDI_RX_BLOCKS &&
		    midi_ratelimit_per_packet(s, port) &&
		    p->midi[port] != NULL &&
		    snd_rawmidi_transmit(p->midi[port], &b[1], 1) == 1) {
			midi_rate_use_one_byte(s, port);
			b[0] = 0x81;
		} else {
			b[0] = 0x80;
			b[1] = 0;
		}
		b[2] = 0;
		b[3] = 0;

		buffer += s->data_block_quadlets;
	}
}

static void read_midi_messages(struct amdtp_stream *s, __be32 *buffer,
			unsigned int frames, unsigned int data_block_counter)
{
	struct amdtp_am824 *p = s->protocol;
	int len;
	u8 *b;
	int f;

	for (f = 0; f < frames; f++) {
		unsigned int port = f;

		if (!(s->flags & CIP_UNALIGHED_DBC))
			port += data_block_counter;
		port %= 8;
		b = (u8 *)&buffer[p->midi_position];

		len = b[0] - 0x80;
		if ((1 <= len) &&  (len <= 3) && (p->midi[port]))
			snd_rawmidi_receive(p->midi[port], b + 1, len);

		buffer += s->data_block_quadlets;
	}
}

static unsigned int process_it_ctx_payloads(struct amdtp_stream *s,
					    const struct pkt_desc *descs,
					    unsigned int packets,
					    struct snd_pcm_substream *pcm)
{
	struct amdtp_am824 *p = s->protocol;
	unsigned int pcm_frames = 0;
	int i;

	for (i = 0; i < packets; ++i) {
		const struct pkt_desc *desc = descs + i;
		__be32 *buf = desc->ctx_payload;
		unsigned int data_blocks = desc->data_blocks;

		if (pcm) {
			write_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
			pcm_frames += data_blocks * p->frame_multiplier;
		} else {
			write_pcm_silence(s, buf, data_blocks);
		}

		if (p->midi_ports) {
			write_midi_messages(s, buf, data_blocks,
					    desc->data_block_counter);
		}
	}

	return pcm_frames;
}

static unsigned int process_ir_ctx_payloads(struct amdtp_stream *s,
					    const struct pkt_desc *descs,
					    unsigned int packets,
					    struct snd_pcm_substream *pcm)
{
	struct amdtp_am824 *p = s->protocol;
	unsigned int pcm_frames = 0;
	int i;

	for (i = 0; i < packets; ++i) {
		const struct pkt_desc *desc = descs + i;
		__be32 *buf = desc->ctx_payload;
		unsigned int data_blocks = desc->data_blocks;

		if (pcm) {
			read_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
			pcm_frames += data_blocks * p->frame_multiplier;
		}

		if (p->midi_ports) {
			read_midi_messages(s, buf, data_blocks,
					   desc->data_block_counter);
		}
	}

	return pcm_frames;
}

/**
 * amdtp_am824_init - initialize an AMDTP stream structure to handle AM824
 *		      data block
 * @s: the AMDTP stream to initialize
 * @unit: the target of the stream
 * @dir: the direction of stream
 * @flags: the packet transmission method to use
 */
int amdtp_am824_init(struct amdtp_stream *s, struct fw_unit *unit,
		     enum amdtp_stream_direction dir, enum cip_flags flags)
{
	amdtp_stream_process_ctx_payloads_t process_ctx_payloads;

	if (dir == AMDTP_IN_STREAM)
		process_ctx_payloads = process_ir_ctx_payloads;
	else
		process_ctx_payloads = process_it_ctx_payloads;

	return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
			process_ctx_payloads, sizeof(struct amdtp_am824));
}
EXPORT_SYMBOL_GPL(amdtp_am824_init);
Commit	Line	Data
da607e19	1	// SPDX-License-Identifier: GPL-2.0-only
5955815e TS	2	/*
	3	* AM824 format in Audio and Music Data Transmission Protocol (IEC 61883-6)
	4	*
df075fee	5	* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
5955815e	6	* Copyright (c) 2015 Takashi Sakamoto <o-takashi@sakamocchi.jp>
5955815e TS	7	*/
5955815e TS	8
df075fee TS	9	#include <linux/slab.h>
df075fee TS	10
5955815e TS	11	#include "amdtp-am824.h"
	12
	13	#define CIP_FMT_AM 0x10
	14
51c29fd2 TS	15	/* "Clock-based rate control mode" is just supported. */
	16	#define AMDTP_FDF_AM824 0x00
	17
df075fee TS	18	/*
	19	* Nominally 3125 bytes/second, but the MIDI port's clock might be
	20	* 1% too slow, and the bus clock 100 ppm too fast.
	21	*/
	22	#define MIDI_BYTES_PER_SECOND 3093
	23
	24	/*
	25	* Several devices look only at the first eight data blocks.
	26	* In any case, this is more than enough for the MIDI data rate.
	27	*/
	28	#define MAX_MIDI_RX_BLOCKS 8
	29
	30	struct amdtp_am824 {
	31	struct snd_rawmidi_substream midi[AM824_MAX_CHANNELS_FOR_MIDI 8];
	32	int midi_fifo_limit;
	33	int midi_fifo_used[AM824_MAX_CHANNELS_FOR_MIDI * 8];
	34	unsigned int pcm_channels;
	35	unsigned int midi_ports;
	36
	37	u8 pcm_positions[AM824_MAX_CHANNELS_FOR_PCM];
	38	u8 midi_position;
	39
df075fee TS	40	unsigned int frame_multiplier;
	41	};
	42
51c29fd2 TS	43	/**
	44	* amdtp_am824_set_parameters - set stream parameters
	45	* @s: the AMDTP stream to configure
	46	* @rate: the sample rate
	47	* @pcm_channels: the number of PCM samples in each data block, to be encoded
	48	* as AM824 multi-bit linear audio
	49	* @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels)
	50	* @double_pcm_frames: one data block transfers two PCM frames
	51	*
	52	* The parameters must be set before the stream is started, and must not be
	53	* changed while the stream is running.
	54	*/
	55	int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate,
	56	unsigned int pcm_channels,
	57	unsigned int midi_ports,
	58	bool double_pcm_frames)
	59	{
df075fee TS	60	struct amdtp_am824 *p = s->protocol;
	61	unsigned int midi_channels;
	62	unsigned int i;
51c29fd2 TS	63	int err;
51c29fd2 TS	64
df075fee TS	65	if (amdtp_stream_running(s))
	66	return -EINVAL;
	67
	68	if (pcm_channels > AM824_MAX_CHANNELS_FOR_PCM)
	69	return -EINVAL;
	70
	71	midi_channels = DIV_ROUND_UP(midi_ports, 8);
	72	if (midi_channels > AM824_MAX_CHANNELS_FOR_MIDI)
	73	return -EINVAL;
	74
	75	if (WARN_ON(amdtp_stream_running(s)) \|\|
	76	WARN_ON(pcm_channels > AM824_MAX_CHANNELS_FOR_PCM) \|\|
	77	WARN_ON(midi_channels > AM824_MAX_CHANNELS_FOR_MIDI))
	78	return -EINVAL;
	79
	80	err = amdtp_stream_set_parameters(s, rate,
	81	pcm_channels + midi_channels);
51c29fd2 TS	82	if (err < 0)
	83	return err;
	84
d3d10a4a	85	s->ctx_data.rx.fdf = AMDTP_FDF_AM824 \| s->sfc;
51c29fd2	86
df075fee TS	87	p->pcm_channels = pcm_channels;
	88	p->midi_ports = midi_ports;
	89
51c29fd2 TS	90	/*
	91	* In IEC 61883-6, one data block represents one event. In ALSA, one
	92	* event equals to one PCM frame. But Dice has a quirk at higher
	93	* sampling rate to transfer two PCM frames in one data block.
	94	*/
	95	if (double_pcm_frames)
df075fee	96	p->frame_multiplier = 2;
51c29fd2	97	else
df075fee TS	98	p->frame_multiplier = 1;
	99
	100	/* init the position map for PCM and MIDI channels */
	101	for (i = 0; i < pcm_channels; i++)
	102	p->pcm_positions[i] = i;
	103	p->midi_position = p->pcm_channels;
	104
	105	/*
	106	* We do not know the actual MIDI FIFO size of most devices. Just
	107	* assume two bytes, i.e., one byte can be received over the bus while
	108	* the previous one is transmitted over MIDI.
	109	* (The value here is adjusted for midi_ratelimit_per_packet().)
	110	*/
	111	p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;
51c29fd2 TS	112
	113	return 0;
	114	}
	115	EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters);
	116
f65be911 TS	117	/**
	118	* amdtp_am824_set_pcm_position - set an index of data channel for a channel
	119	* of PCM frame
	120	* @s: the AMDTP stream
	121	* @index: the index of data channel in an data block
	122	* @position: the channel of PCM frame
	123	*/
	124	void amdtp_am824_set_pcm_position(struct amdtp_stream *s, unsigned int index,
	125	unsigned int position)
	126	{
df075fee TS	127	struct amdtp_am824 *p = s->protocol;
	128
	129	if (index < p->pcm_channels)
	130	p->pcm_positions[index] = position;
f65be911 TS	131	}
	132	EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_position);
	133
	134	/**
	135	* amdtp_am824_set_midi_position - set a index of data channel for MIDI
	136	* conformant data channel
	137	* @s: the AMDTP stream
	138	* @position: the index of data channel in an data block
	139	*/
	140	void amdtp_am824_set_midi_position(struct amdtp_stream *s,
	141	unsigned int position)
	142	{
df075fee TS	143	struct amdtp_am824 *p = s->protocol;
	144
	145	p->midi_position = position;
f65be911 TS	146	}
	147	EXPORT_SYMBOL_GPL(amdtp_am824_set_midi_position);
	148
9fc90644 TS	149	static void write_pcm_s32(struct amdtp_stream s, struct snd_pcm_substream pcm,
	150	__be32 *buffer, unsigned int frames,
	151	unsigned int pcm_frames)
df075fee TS	152	{
df075fee TS	153	struct amdtp_am824 *p = s->protocol;
9fc90644	154	unsigned int channels = p->pcm_channels;
df075fee	155	struct snd_pcm_runtime *runtime = pcm->runtime;
9fc90644 TS	156	unsigned int pcm_buffer_pointer;
9fc90644 TS	157	int remaining_frames;
df075fee	158	const u32 *src;
9fc90644 TS	159	int i, c;
	160
	161	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
	162	pcm_buffer_pointer %= runtime->buffer_size;
df075fee	163
df075fee	164	src = (void *)runtime->dma_area +
9fc90644 TS	165	frames_to_bytes(runtime, pcm_buffer_pointer);
9fc90644 TS	166	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
df075fee TS	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
9fc90644 TS	180	static void read_pcm_s32(struct amdtp_stream s, struct snd_pcm_substream pcm,
	181	__be32 *buffer, unsigned int frames,
	182	unsigned int pcm_frames)
df075fee TS	183	{
df075fee TS	184	struct amdtp_am824 *p = s->protocol;
9fc90644	185	unsigned int channels = p->pcm_channels;
df075fee	186	struct snd_pcm_runtime *runtime = pcm->runtime;
9fc90644 TS	187	unsigned int pcm_buffer_pointer;
9fc90644 TS	188	int remaining_frames;
df075fee	189	u32 *dst;
9fc90644 TS	190	int i, c;
	191
	192	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
	193	pcm_buffer_pointer %= runtime->buffer_size;
df075fee	194
df075fee	195	dst = (void *)runtime->dma_area +
9fc90644 TS	196	frames_to_bytes(runtime, pcm_buffer_pointer);
9fc90644 TS	197	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
df075fee TS	198
	199	for (i = 0; i < frames; ++i) {
	200	for (c = 0; c < channels; ++c) {
	201	*dst = be32_to_cpu(buffer[p->pcm_positions[c]]) << 8;
	202	dst++;
	203	}
	204	buffer += s->data_block_quadlets;
	205	if (--remaining_frames == 0)
	206	dst = (void *)runtime->dma_area;
	207	}
	208	}
	209
	210	static void write_pcm_silence(struct amdtp_stream *s,
	211	__be32 *buffer, unsigned int frames)
	212	{
	213	struct amdtp_am824 *p = s->protocol;
	214	unsigned int i, c, channels = p->pcm_channels;
	215
	216	for (i = 0; i < frames; ++i) {
	217	for (c = 0; c < channels; ++c)
	218	buffer[p->pcm_positions[c]] = cpu_to_be32(0x40000000);
	219	buffer += s->data_block_quadlets;
	220	}
	221	}
	222
bc8500da TS	223	/**
	224	* amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream
	225	* @s: the AMDTP stream for AM824 data block, must be initialized.
	226	* @runtime: the PCM substream runtime
	227	*
	228	*/
	229	int amdtp_am824_add_pcm_hw_constraints(struct amdtp_stream *s,
	230	struct snd_pcm_runtime *runtime)
	231	{
	232	int err;
	233
	234	err = amdtp_stream_add_pcm_hw_constraints(s, runtime);
	235	if (err < 0)
	236	return err;
	237
	238	/* AM824 in IEC 61883-6 can deliver 24bit data. */
	239	return snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
	240	}
	241	EXPORT_SYMBOL_GPL(amdtp_am824_add_pcm_hw_constraints);
	242
03e2a67e TS	243	/**
	244	* amdtp_am824_midi_trigger - start/stop playback/capture with a MIDI device
	245	* @s: the AMDTP stream
	246	* @port: index of MIDI port
	247	* @midi: the MIDI device to be started, or %NULL to stop the current device
	248	*
	249	* Call this function on a running isochronous stream to enable the actual
	250	* transmission of MIDI data. This function should be called from the MIDI
	251	* device's .trigger callback.
	252	*/
	253	void amdtp_am824_midi_trigger(struct amdtp_stream *s, unsigned int port,
	254	struct snd_rawmidi_substream *midi)
	255	{
df075fee TS	256	struct amdtp_am824 *p = s->protocol;
	257
	258	if (port < p->midi_ports)
6aa7de05	259	WRITE_ONCE(p->midi[port], midi);
03e2a67e TS	260	}
	261	EXPORT_SYMBOL_GPL(amdtp_am824_midi_trigger);
	262
df075fee TS	263	/*
	264	* To avoid sending MIDI bytes at too high a rate, assume that the receiving
	265	* device has a FIFO, and track how much it is filled. This values increases
	266	* by one whenever we send one byte in a packet, but the FIFO empties at
	267	* a constant rate independent of our packet rate. One packet has syt_interval
	268	* samples, so the number of bytes that empty out of the FIFO, per packet(!),
	269	* is MIDI_BYTES_PER_SECOND * syt_interval / sample_rate. To avoid storing
	270	* fractional values, the values in midi_fifo_used[] are measured in bytes
	271	* multiplied by the sample rate.
	272	*/
	273	static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
	274	{
	275	struct amdtp_am824 *p = s->protocol;
	276	int used;
	277
	278	used = p->midi_fifo_used[port];
	279	if (used == 0) /* common shortcut */
	280	return true;
	281
	282	used -= MIDI_BYTES_PER_SECOND * s->syt_interval;
	283	used = max(used, 0);
	284	p->midi_fifo_used[port] = used;
	285
	286	return used < p->midi_fifo_limit;
	287	}
	288
	289	static void midi_rate_use_one_byte(struct amdtp_stream *s, unsigned int port)
	290	{
	291	struct amdtp_am824 *p = s->protocol;
	292
	293	p->midi_fifo_used[port] += amdtp_rate_table[s->sfc];
	294	}
	295
	296	static void write_midi_messages(struct amdtp_stream s, __be32 buffer,
ab754812	297	unsigned int frames, unsigned int data_block_counter)
df075fee TS	298	{
	299	struct amdtp_am824 *p = s->protocol;
	300	unsigned int f, port;
	301	u8 *b;
	302
	303	for (f = 0; f < frames; f++) {
	304	b = (u8 *)&buffer[p->midi_position];
	305
ab754812	306	port = (data_block_counter + f) % 8;
df075fee TS	307	if (f < MAX_MIDI_RX_BLOCKS &&
	308	midi_ratelimit_per_packet(s, port) &&
	309	p->midi[port] != NULL &&
	310	snd_rawmidi_transmit(p->midi[port], &b[1], 1) == 1) {
	311	midi_rate_use_one_byte(s, port);
	312	b[0] = 0x81;
	313	} else {
	314	b[0] = 0x80;
	315	b[1] = 0;
	316	}
	317	b[2] = 0;
	318	b[3] = 0;
	319
	320	buffer += s->data_block_quadlets;
	321	}
	322	}
	323
ab754812 TS	324	static void read_midi_messages(struct amdtp_stream s, __be32 buffer,
ab754812 TS	325	unsigned int frames, unsigned int data_block_counter)
df075fee TS	326	{
df075fee TS	327	struct amdtp_am824 *p = s->protocol;
df075fee TS	328	int len;
df075fee TS	329	u8 *b;
588f2e2c	330	int f;
df075fee TS	331
df075fee TS	332	for (f = 0; f < frames; f++) {
588f2e2c TS	333	unsigned int port = f;
	334
	335	if (!(s->flags & CIP_UNALIGHED_DBC))
ab754812	336	port += data_block_counter;
588f2e2c	337	port %= 8;
df075fee TS	338	b = (u8 *)&buffer[p->midi_position];
	339
	340	len = b[0] - 0x80;
	341	if ((1 <= len) && (len <= 3) && (p->midi[port]))
	342	snd_rawmidi_receive(p->midi[port], b + 1, len);
	343
	344	buffer += s->data_block_quadlets;
	345	}
	346	}
	347
9a738ad1 TS	348	static unsigned int process_it_ctx_payloads(struct amdtp_stream *s,
	349	const struct pkt_desc *descs,
	350	unsigned int packets,
	351	struct snd_pcm_substream *pcm)
df075fee TS	352	{
df075fee TS	353	struct amdtp_am824 *p = s->protocol;
9fc90644	354	unsigned int pcm_frames = 0;
9a738ad1	355	int i;
df075fee	356
9a738ad1 TS	357	for (i = 0; i < packets; ++i) {
	358	const struct pkt_desc *desc = descs + i;
	359	__be32 *buf = desc->ctx_payload;
	360	unsigned int data_blocks = desc->data_blocks;
df075fee	361
9a738ad1 TS	362	if (pcm) {
	363	write_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
	364	pcm_frames += data_blocks * p->frame_multiplier;
	365	} else {
	366	write_pcm_silence(s, buf, data_blocks);
	367	}
	368
	369	if (p->midi_ports) {
	370	write_midi_messages(s, buf, data_blocks,
	371	desc->data_block_counter);
	372	}
d2c104a3	373	}
df075fee TS	374
	375	return pcm_frames;
	376	}
	377
9a738ad1 TS	378	static unsigned int process_ir_ctx_payloads(struct amdtp_stream *s,
	379	const struct pkt_desc *descs,
	380	unsigned int packets,
	381	struct snd_pcm_substream *pcm)
df075fee TS	382	{
df075fee TS	383	struct amdtp_am824 *p = s->protocol;
9fc90644	384	unsigned int pcm_frames = 0;
9a738ad1	385	int i;
df075fee	386
9a738ad1 TS	387	for (i = 0; i < packets; ++i) {
	388	const struct pkt_desc *desc = descs + i;
	389	__be32 *buf = desc->ctx_payload;
	390	unsigned int data_blocks = desc->data_blocks;
	391
	392	if (pcm) {
	393	read_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
	394	pcm_frames += data_blocks * p->frame_multiplier;
	395	}
df075fee	396
9a738ad1 TS	397	if (p->midi_ports) {
	398	read_midi_messages(s, buf, data_blocks,
	399	desc->data_block_counter);
	400	}
d2c104a3	401	}
df075fee TS	402
	403	return pcm_frames;
	404	}
	405
5955815e TS	406	/**
	407	* amdtp_am824_init - initialize an AMDTP stream structure to handle AM824
	408	* data block
	409	* @s: the AMDTP stream to initialize
	410	* @unit: the target of the stream
	411	* @dir: the direction of stream
	412	* @flags: the packet transmission method to use
	413	*/
	414	int amdtp_am824_init(struct amdtp_stream s, struct fw_unit unit,
	415	enum amdtp_stream_direction dir, enum cip_flags flags)
	416	{
9a738ad1	417	amdtp_stream_process_ctx_payloads_t process_ctx_payloads;
df075fee TS	418
df075fee TS	419	if (dir == AMDTP_IN_STREAM)
9a738ad1	420	process_ctx_payloads = process_ir_ctx_payloads;
df075fee	421	else
9a738ad1	422	process_ctx_payloads = process_it_ctx_payloads;
df075fee TS	423
df075fee TS	424	return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
9a738ad1	425	process_ctx_payloads, sizeof(struct amdtp_am824));
5955815e TS	426	}
5955815e TS	427	EXPORT_SYMBOL_GPL(amdtp_am824_init);