diff options
Diffstat (limited to 'kernel/sound/firewire/amdtp-am824.c')
| -rw-r--r-- | kernel/sound/firewire/amdtp-am824.c | 465 |
1 files changed, 465 insertions, 0 deletions
diff --git a/kernel/sound/firewire/amdtp-am824.c b/kernel/sound/firewire/amdtp-am824.c new file mode 100644 index 000000000..bebddc60f --- /dev/null +++ b/kernel/sound/firewire/amdtp-am824.c @@ -0,0 +1,465 @@ +/* + * 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> + * + * Licensed under the terms of the GNU General Public License, version 2. + */ + +#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; + + void (*transfer_samples)(struct amdtp_stream *s, + struct snd_pcm_substream *pcm, + __be32 *buffer, unsigned int frames); + + 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->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) +{ + struct amdtp_am824 *p = s->protocol; + struct snd_pcm_runtime *runtime = pcm->runtime; + unsigned int channels, remaining_frames, i, c; + const u32 *src; + + channels = p->pcm_channels; + src = (void *)runtime->dma_area + + frames_to_bytes(runtime, s->pcm_buffer_pointer); + remaining_frames = runtime->buffer_size - s->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 write_pcm_s16(struct amdtp_stream *s, + struct snd_pcm_substream *pcm, + __be32 *buffer, unsigned int frames) +{ + struct amdtp_am824 *p = s->protocol; + struct snd_pcm_runtime *runtime = pcm->runtime; + unsigned int channels, remaining_frames, i, c; + const u16 *src; + + channels = p->pcm_channels; + src = (void *)runtime->dma_area + + frames_to_bytes(runtime, s->pcm_buffer_pointer); + remaining_frames = runtime->buffer_size - s->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) | 0x42000000); + 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) +{ + struct amdtp_am824 *p = s->protocol; + struct snd_pcm_runtime *runtime = pcm->runtime; + unsigned int channels, remaining_frames, i, c; + u32 *dst; + + channels = p->pcm_channels; + dst = (void *)runtime->dma_area + + frames_to_bytes(runtime, s->pcm_buffer_pointer); + remaining_frames = runtime->buffer_size - s->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_set_pcm_format - set the PCM format + * @s: the AMDTP stream to configure + * @format: the format of the ALSA PCM device + * + * The sample format must be set after the other parameters (rate/PCM channels/ + * MIDI) and before the stream is started, and must not be changed while the + * stream is running. + */ +void amdtp_am824_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format) +{ + struct amdtp_am824 *p = s->protocol; + + if (WARN_ON(amdtp_stream_pcm_running(s))) + return; + + switch (format) { + default: + WARN_ON(1); + /* fall through */ + case SNDRV_PCM_FORMAT_S16: + if (s->direction == AMDTP_OUT_STREAM) { + p->transfer_samples = write_pcm_s16; + break; + } + WARN_ON(1); + /* fall through */ + case SNDRV_PCM_FORMAT_S32: + if (s->direction == AMDTP_OUT_STREAM) + p->transfer_samples = write_pcm_s32; + else + p->transfer_samples = read_pcm_s32; + break; + } +} +EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_format); + +/** + * 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) + ACCESS_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) +{ + 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 = (s->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) +{ + struct amdtp_am824 *p = s->protocol; + unsigned int f, port; + int len; + u8 *b; + + for (f = 0; f < frames; f++) { + port = (s->data_block_counter + f) % 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_rx_data_blocks(struct amdtp_stream *s, __be32 *buffer, + unsigned int data_blocks, unsigned int *syt) +{ + struct amdtp_am824 *p = s->protocol; + struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm); + unsigned int pcm_frames; + + if (pcm) { + p->transfer_samples(s, pcm, buffer, data_blocks); + pcm_frames = data_blocks * p->frame_multiplier; + } else { + write_pcm_silence(s, buffer, data_blocks); + pcm_frames = 0; + } + + if (p->midi_ports) + write_midi_messages(s, buffer, data_blocks); + + return pcm_frames; +} + +static unsigned int process_tx_data_blocks(struct amdtp_stream *s, __be32 *buffer, + unsigned int data_blocks, unsigned int *syt) +{ + struct amdtp_am824 *p = s->protocol; + struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm); + unsigned int pcm_frames; + + if (pcm) { + p->transfer_samples(s, pcm, buffer, data_blocks); + pcm_frames = data_blocks * p->frame_multiplier; + } else { + pcm_frames = 0; + } + + if (p->midi_ports) + read_midi_messages(s, buffer, data_blocks); + + 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_data_blocks_t process_data_blocks; + + if (dir == AMDTP_IN_STREAM) + process_data_blocks = process_tx_data_blocks; + else + process_data_blocks = process_rx_data_blocks; + + return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM, + process_data_blocks, + sizeof(struct amdtp_am824)); +} +EXPORT_SYMBOL_GPL(amdtp_am824_init); |