[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;
};

/**
 * 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 pcm_frame_multiplier;
	int i, 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;

	/*
	 * 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)
		pcm_frame_multiplier = 2;
	else
		pcm_frame_multiplier = 1;

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

	if (s->direction == AMDTP_OUT_STREAM)
		s->ctx_data.rx.fdf = AMDTP_FDF_AM824 | s->sfc;

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

	/* 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 void process_it_ctx_payloads(struct amdtp_stream *s, const struct pkt_desc *desc,
				    unsigned int count, struct snd_pcm_substream *pcm)
{
	struct amdtp_am824 *p = s->protocol;
	unsigned int pcm_frames = 0;
	int i;

	for (i = 0; i < count; ++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 * s->pcm_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);
		}

		desc = amdtp_stream_next_packet_desc(s, desc);
	}
}

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

	for (i = 0; i < count; ++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 * s->pcm_frame_multiplier;
		}

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

		desc = amdtp_stream_next_packet_desc(s, desc);
	}
}

/**
 * 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 details of the streaming protocol consist of cip_flags enumeration-constants.
 */
int amdtp_am824_init(struct amdtp_stream *s, struct fw_unit *unit,
		     enum amdtp_stream_direction dir, unsigned int 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;
df075fee TS	39	};
df075fee TS	40
51c29fd2 TS	41	/**
	42	* amdtp_am824_set_parameters - set stream parameters
	43	* @s: the AMDTP stream to configure
	44	* @rate: the sample rate
	45	* @pcm_channels: the number of PCM samples in each data block, to be encoded
	46	* as AM824 multi-bit linear audio
	47	* @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels)
	48	* @double_pcm_frames: one data block transfers two PCM frames
	49	*
	50	* The parameters must be set before the stream is started, and must not be
	51	* changed while the stream is running.
	52	*/
	53	int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate,
	54	unsigned int pcm_channels,
	55	unsigned int midi_ports,
	56	bool double_pcm_frames)
	57	{
df075fee TS	58	struct amdtp_am824 *p = s->protocol;
df075fee TS	59	unsigned int midi_channels;
a36183f6 TS	60	unsigned int pcm_frame_multiplier;
a36183f6 TS	61	int i, err;
51c29fd2	62
df075fee TS	63	if (amdtp_stream_running(s))
	64	return -EINVAL;
	65
	66	if (pcm_channels > AM824_MAX_CHANNELS_FOR_PCM)
	67	return -EINVAL;
	68
	69	midi_channels = DIV_ROUND_UP(midi_ports, 8);
	70	if (midi_channels > AM824_MAX_CHANNELS_FOR_MIDI)
	71	return -EINVAL;
	72
	73	if (WARN_ON(amdtp_stream_running(s)) \|\|
	74	WARN_ON(pcm_channels > AM824_MAX_CHANNELS_FOR_PCM) \|\|
	75	WARN_ON(midi_channels > AM824_MAX_CHANNELS_FOR_MIDI))
	76	return -EINVAL;
	77
a36183f6 TS	78	/*
	79	* In IEC 61883-6, one data block represents one event. In ALSA, one
	80	* event equals to one PCM frame. But Dice has a quirk at higher
	81	* sampling rate to transfer two PCM frames in one data block.
	82	*/
	83	if (double_pcm_frames)
	84	pcm_frame_multiplier = 2;
	85	else
	86	pcm_frame_multiplier = 1;
	87
	88	err = amdtp_stream_set_parameters(s, rate, pcm_channels + midi_channels,
	89	pcm_frame_multiplier);
51c29fd2 TS	90	if (err < 0)
	91	return err;
	92
8304cf77 TS	93	if (s->direction == AMDTP_OUT_STREAM)
8304cf77 TS	94	s->ctx_data.rx.fdf = AMDTP_FDF_AM824 \| s->sfc;
51c29fd2	95
df075fee TS	96	p->pcm_channels = pcm_channels;
	97	p->midi_ports = midi_ports;
	98
df075fee TS	99	/* init the position map for PCM and MIDI channels */
	100	for (i = 0; i < pcm_channels; i++)
	101	p->pcm_positions[i] = i;
	102	p->midi_position = p->pcm_channels;
	103
	104	/*
	105	* We do not know the actual MIDI FIFO size of most devices. Just
	106	* assume two bytes, i.e., one byte can be received over the bus while
	107	* the previous one is transmitted over MIDI.
	108	* (The value here is adjusted for midi_ratelimit_per_packet().)
	109	*/
	110	p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;
51c29fd2 TS	111
	112	return 0;
	113	}
	114	EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters);
	115
f65be911 TS	116	/**
	117	* amdtp_am824_set_pcm_position - set an index of data channel for a channel
	118	* of PCM frame
	119	* @s: the AMDTP stream
	120	* @index: the index of data channel in an data block
	121	* @position: the channel of PCM frame
	122	*/
	123	void amdtp_am824_set_pcm_position(struct amdtp_stream *s, unsigned int index,
	124	unsigned int position)
	125	{
df075fee TS	126	struct amdtp_am824 *p = s->protocol;
	127
	128	if (index < p->pcm_channels)
	129	p->pcm_positions[index] = position;
f65be911 TS	130	}
	131	EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_position);
	132
	133	/**
	134	* amdtp_am824_set_midi_position - set a index of data channel for MIDI
	135	* conformant data channel
	136	* @s: the AMDTP stream
	137	* @position: the index of data channel in an data block
	138	*/
	139	void amdtp_am824_set_midi_position(struct amdtp_stream *s,
	140	unsigned int position)
	141	{
df075fee TS	142	struct amdtp_am824 *p = s->protocol;
	143
	144	p->midi_position = position;
f65be911 TS	145	}
	146	EXPORT_SYMBOL_GPL(amdtp_am824_set_midi_position);
	147
9fc90644 TS	148	static void write_pcm_s32(struct amdtp_stream s, struct snd_pcm_substream pcm,
	149	__be32 *buffer, unsigned int frames,
	150	unsigned int pcm_frames)
df075fee TS	151	{
df075fee TS	152	struct amdtp_am824 *p = s->protocol;
9fc90644	153	unsigned int channels = p->pcm_channels;
df075fee	154	struct snd_pcm_runtime *runtime = pcm->runtime;
9fc90644 TS	155	unsigned int pcm_buffer_pointer;
9fc90644 TS	156	int remaining_frames;
df075fee	157	const u32 *src;
9fc90644 TS	158	int i, c;
	159
	160	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
	161	pcm_buffer_pointer %= runtime->buffer_size;
df075fee	162
df075fee	163	src = (void *)runtime->dma_area +
9fc90644 TS	164	frames_to_bytes(runtime, pcm_buffer_pointer);
9fc90644 TS	165	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
df075fee TS	166
	167	for (i = 0; i < frames; ++i) {
	168	for (c = 0; c < channels; ++c) {
	169	buffer[p->pcm_positions[c]] =
	170	cpu_to_be32((*src >> 8) \| 0x40000000);
	171	src++;
	172	}
	173	buffer += s->data_block_quadlets;
	174	if (--remaining_frames == 0)
	175	src = (void *)runtime->dma_area;
	176	}
	177	}
	178
9fc90644 TS	179	static void read_pcm_s32(struct amdtp_stream s, struct snd_pcm_substream pcm,
	180	__be32 *buffer, unsigned int frames,
	181	unsigned int pcm_frames)
df075fee TS	182	{
df075fee TS	183	struct amdtp_am824 *p = s->protocol;
9fc90644	184	unsigned int channels = p->pcm_channels;
df075fee	185	struct snd_pcm_runtime *runtime = pcm->runtime;
9fc90644 TS	186	unsigned int pcm_buffer_pointer;
9fc90644 TS	187	int remaining_frames;
df075fee	188	u32 *dst;
9fc90644 TS	189	int i, c;
	190
	191	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
	192	pcm_buffer_pointer %= runtime->buffer_size;
df075fee	193
df075fee	194	dst = (void *)runtime->dma_area +
9fc90644 TS	195	frames_to_bytes(runtime, pcm_buffer_pointer);
9fc90644 TS	196	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
df075fee TS	197
	198	for (i = 0; i < frames; ++i) {
	199	for (c = 0; c < channels; ++c) {
	200	*dst = be32_to_cpu(buffer[p->pcm_positions[c]]) << 8;
	201	dst++;
	202	}
	203	buffer += s->data_block_quadlets;
	204	if (--remaining_frames == 0)
	205	dst = (void *)runtime->dma_area;
	206	}
	207	}
	208
	209	static void write_pcm_silence(struct amdtp_stream *s,
	210	__be32 *buffer, unsigned int frames)
	211	{
	212	struct amdtp_am824 *p = s->protocol;
	213	unsigned int i, c, channels = p->pcm_channels;
	214
	215	for (i = 0; i < frames; ++i) {
	216	for (c = 0; c < channels; ++c)
	217	buffer[p->pcm_positions[c]] = cpu_to_be32(0x40000000);
	218	buffer += s->data_block_quadlets;
	219	}
	220	}
	221
bc8500da TS	222	/**
	223	* amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream
	224	* @s: the AMDTP stream for AM824 data block, must be initialized.
	225	* @runtime: the PCM substream runtime
	226	*
	227	*/
	228	int amdtp_am824_add_pcm_hw_constraints(struct amdtp_stream *s,
	229	struct snd_pcm_runtime *runtime)
	230	{
	231	int err;
	232
	233	err = amdtp_stream_add_pcm_hw_constraints(s, runtime);
	234	if (err < 0)
	235	return err;
	236
	237	/* AM824 in IEC 61883-6 can deliver 24bit data. */
	238	return snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
	239	}
	240	EXPORT_SYMBOL_GPL(amdtp_am824_add_pcm_hw_constraints);
	241
03e2a67e TS	242	/**
	243	* amdtp_am824_midi_trigger - start/stop playback/capture with a MIDI device
	244	* @s: the AMDTP stream
	245	* @port: index of MIDI port
	246	* @midi: the MIDI device to be started, or %NULL to stop the current device
	247	*
	248	* Call this function on a running isochronous stream to enable the actual
	249	* transmission of MIDI data. This function should be called from the MIDI
	250	* device's .trigger callback.
	251	*/
	252	void amdtp_am824_midi_trigger(struct amdtp_stream *s, unsigned int port,
	253	struct snd_rawmidi_substream *midi)
	254	{
df075fee TS	255	struct amdtp_am824 *p = s->protocol;
	256
	257	if (port < p->midi_ports)
6aa7de05	258	WRITE_ONCE(p->midi[port], midi);
03e2a67e TS	259	}
	260	EXPORT_SYMBOL_GPL(amdtp_am824_midi_trigger);
	261
df075fee TS	262	/*
	263	* To avoid sending MIDI bytes at too high a rate, assume that the receiving
	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
	266	* a constant rate independent of our packet rate. One packet has syt_interval
	267	* samples, so the number of bytes that empty out of the FIFO, per packet(!),
	268	* is MIDI_BYTES_PER_SECOND * syt_interval / sample_rate. To avoid storing
	269	* fractional values, the values in midi_fifo_used[] are measured in bytes
	270	* multiplied by the sample rate.
	271	*/
	272	static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
	273	{
	274	struct amdtp_am824 *p = s->protocol;
	275	int used;
	276
	277	used = p->midi_fifo_used[port];
	278	if (used == 0) /* common shortcut */
	279	return true;
	280
	281	used -= MIDI_BYTES_PER_SECOND * s->syt_interval;
	282	used = max(used, 0);
	283	p->midi_fifo_used[port] = used;
	284
	285	return used < p->midi_fifo_limit;
	286	}
	287
	288	static void midi_rate_use_one_byte(struct amdtp_stream *s, unsigned int port)
	289	{
	290	struct amdtp_am824 *p = s->protocol;
	291
	292	p->midi_fifo_used[port] += amdtp_rate_table[s->sfc];
	293	}
	294
	295	static void write_midi_messages(struct amdtp_stream s, __be32 buffer,
ab754812	296	unsigned int frames, unsigned int data_block_counter)
df075fee TS	297	{
	298	struct amdtp_am824 *p = s->protocol;
	299	unsigned int f, port;
	300	u8 *b;
	301
	302	for (f = 0; f < frames; f++) {
	303	b = (u8 *)&buffer[p->midi_position];
	304
ab754812	305	port = (data_block_counter + f) % 8;
df075fee TS	306	if (f < MAX_MIDI_RX_BLOCKS &&
	307	midi_ratelimit_per_packet(s, port) &&
	308	p->midi[port] != NULL &&
	309	snd_rawmidi_transmit(p->midi[port], &b[1], 1) == 1) {
	310	midi_rate_use_one_byte(s, port);
	311	b[0] = 0x81;
	312	} else {
	313	b[0] = 0x80;
	314	b[1] = 0;
	315	}
	316	b[2] = 0;
	317	b[3] = 0;
	318
	319	buffer += s->data_block_quadlets;
	320	}
	321	}
	322
ab754812 TS	323	static void read_midi_messages(struct amdtp_stream s, __be32 buffer,
ab754812 TS	324	unsigned int frames, unsigned int data_block_counter)
df075fee TS	325	{
df075fee TS	326	struct amdtp_am824 *p = s->protocol;
df075fee TS	327	int len;
df075fee TS	328	u8 *b;
588f2e2c	329	int f;
df075fee TS	330
df075fee TS	331	for (f = 0; f < frames; f++) {
588f2e2c TS	332	unsigned int port = f;
	333
	334	if (!(s->flags & CIP_UNALIGHED_DBC))
ab754812	335	port += data_block_counter;
588f2e2c	336	port %= 8;
df075fee TS	337	b = (u8 *)&buffer[p->midi_position];
	338
	339	len = b[0] - 0x80;
	340	if ((1 <= len) && (len <= 3) && (p->midi[port]))
	341	snd_rawmidi_receive(p->midi[port], b + 1, len);
	342
	343	buffer += s->data_block_quadlets;
	344	}
	345	}
	346
7fc693e4 TS	347	static void process_it_ctx_payloads(struct amdtp_stream s, const struct pkt_desc desc,
7fc693e4 TS	348	unsigned int count, struct snd_pcm_substream *pcm)
df075fee TS	349	{
df075fee TS	350	struct amdtp_am824 *p = s->protocol;
9fc90644	351	unsigned int pcm_frames = 0;
9a738ad1	352	int i;
df075fee	353
0cac60c7	354	for (i = 0; i < count; ++i) {
9a738ad1 TS	355	__be32 *buf = desc->ctx_payload;
9a738ad1 TS	356	unsigned int data_blocks = desc->data_blocks;
df075fee	357
9a738ad1 TS	358	if (pcm) {
9a738ad1 TS	359	write_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
a36183f6	360	pcm_frames += data_blocks * s->pcm_frame_multiplier;
9a738ad1 TS	361	} else {
	362	write_pcm_silence(s, buf, data_blocks);
	363	}
	364
	365	if (p->midi_ports) {
	366	write_midi_messages(s, buf, data_blocks,
	367	desc->data_block_counter);
	368	}
0cac60c7 TS	369
0cac60c7 TS	370	desc = amdtp_stream_next_packet_desc(s, desc);
d2c104a3	371	}
df075fee TS	372	}
df075fee TS	373
7fc693e4 TS	374	static void process_ir_ctx_payloads(struct amdtp_stream s, const struct pkt_desc desc,
7fc693e4 TS	375	unsigned int count, struct snd_pcm_substream *pcm)
df075fee TS	376	{
df075fee TS	377	struct amdtp_am824 *p = s->protocol;
9fc90644	378	unsigned int pcm_frames = 0;
9a738ad1	379	int i;
df075fee	380
0cac60c7	381	for (i = 0; i < count; ++i) {
9a738ad1 TS	382	__be32 *buf = desc->ctx_payload;
	383	unsigned int data_blocks = desc->data_blocks;
	384
	385	if (pcm) {
	386	read_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
a36183f6	387	pcm_frames += data_blocks * s->pcm_frame_multiplier;
9a738ad1	388	}
df075fee	389
9a738ad1 TS	390	if (p->midi_ports) {
	391	read_midi_messages(s, buf, data_blocks,
	392	desc->data_block_counter);
	393	}
0cac60c7 TS	394
0cac60c7 TS	395	desc = amdtp_stream_next_packet_desc(s, desc);
d2c104a3	396	}
df075fee TS	397	}
df075fee TS	398
5955815e TS	399	/**
	400	* amdtp_am824_init - initialize an AMDTP stream structure to handle AM824
	401	* data block
	402	* @s: the AMDTP stream to initialize
	403	* @unit: the target of the stream
	404	* @dir: the direction of stream
ffe66bbe	405	* @flags: the details of the streaming protocol consist of cip_flags enumeration-constants.
5955815e TS	406	*/
5955815e TS	407	int amdtp_am824_init(struct amdtp_stream s, struct fw_unit unit,
ffe66bbe	408	enum amdtp_stream_direction dir, unsigned int flags)
5955815e	409	{
9a738ad1	410	amdtp_stream_process_ctx_payloads_t process_ctx_payloads;
df075fee TS	411
df075fee TS	412	if (dir == AMDTP_IN_STREAM)
9a738ad1	413	process_ctx_payloads = process_ir_ctx_payloads;
df075fee	414	else
9a738ad1	415	process_ctx_payloads = process_it_ctx_payloads;
df075fee TS	416
df075fee TS	417	return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
9a738ad1	418	process_ctx_payloads, sizeof(struct amdtp_am824));
5955815e TS	419	}
5955815e TS	420	EXPORT_SYMBOL_GPL(amdtp_am824_init);