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8304cf77c9
Although the value of FDF is used just for outgoing stream, the assignment
to union member is done for both directions of stream. At present this
causes no issue because the value of same position is reassigned later for
opposite stream. However, it's better to add if statement.
Fixes: d3d10a4a1b
("ALSA: firewire-lib: use union for directional parameters")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200508043635.349339-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
429 lines
12 KiB
C
429 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* AM824 format in Audio and Music Data Transmission Protocol (IEC 61883-6)
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*
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* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
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* Copyright (c) 2015 Takashi Sakamoto <o-takashi@sakamocchi.jp>
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*/
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#include <linux/slab.h>
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#include "amdtp-am824.h"
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#define CIP_FMT_AM 0x10
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/* "Clock-based rate control mode" is just supported. */
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#define AMDTP_FDF_AM824 0x00
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/*
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* Nominally 3125 bytes/second, but the MIDI port's clock might be
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* 1% too slow, and the bus clock 100 ppm too fast.
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*/
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#define MIDI_BYTES_PER_SECOND 3093
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/*
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* Several devices look only at the first eight data blocks.
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* In any case, this is more than enough for the MIDI data rate.
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*/
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#define MAX_MIDI_RX_BLOCKS 8
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struct amdtp_am824 {
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struct snd_rawmidi_substream *midi[AM824_MAX_CHANNELS_FOR_MIDI * 8];
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int midi_fifo_limit;
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int midi_fifo_used[AM824_MAX_CHANNELS_FOR_MIDI * 8];
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unsigned int pcm_channels;
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unsigned int midi_ports;
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u8 pcm_positions[AM824_MAX_CHANNELS_FOR_PCM];
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u8 midi_position;
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unsigned int frame_multiplier;
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};
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/**
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* amdtp_am824_set_parameters - set stream parameters
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* @s: the AMDTP stream to configure
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* @rate: the sample rate
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* @pcm_channels: the number of PCM samples in each data block, to be encoded
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* as AM824 multi-bit linear audio
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* @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels)
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* @double_pcm_frames: one data block transfers two PCM frames
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*
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* The parameters must be set before the stream is started, and must not be
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* changed while the stream is running.
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*/
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int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate,
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unsigned int pcm_channels,
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unsigned int midi_ports,
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bool double_pcm_frames)
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{
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struct amdtp_am824 *p = s->protocol;
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unsigned int midi_channels;
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unsigned int i;
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int err;
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if (amdtp_stream_running(s))
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return -EINVAL;
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if (pcm_channels > AM824_MAX_CHANNELS_FOR_PCM)
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return -EINVAL;
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midi_channels = DIV_ROUND_UP(midi_ports, 8);
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if (midi_channels > AM824_MAX_CHANNELS_FOR_MIDI)
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return -EINVAL;
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if (WARN_ON(amdtp_stream_running(s)) ||
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WARN_ON(pcm_channels > AM824_MAX_CHANNELS_FOR_PCM) ||
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WARN_ON(midi_channels > AM824_MAX_CHANNELS_FOR_MIDI))
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return -EINVAL;
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err = amdtp_stream_set_parameters(s, rate,
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pcm_channels + midi_channels);
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if (err < 0)
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return err;
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if (s->direction == AMDTP_OUT_STREAM)
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s->ctx_data.rx.fdf = AMDTP_FDF_AM824 | s->sfc;
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p->pcm_channels = pcm_channels;
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p->midi_ports = midi_ports;
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/*
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* In IEC 61883-6, one data block represents one event. In ALSA, one
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* event equals to one PCM frame. But Dice has a quirk at higher
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* sampling rate to transfer two PCM frames in one data block.
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*/
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if (double_pcm_frames)
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p->frame_multiplier = 2;
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else
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p->frame_multiplier = 1;
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/* init the position map for PCM and MIDI channels */
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for (i = 0; i < pcm_channels; i++)
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p->pcm_positions[i] = i;
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p->midi_position = p->pcm_channels;
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/*
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* We do not know the actual MIDI FIFO size of most devices. Just
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* assume two bytes, i.e., one byte can be received over the bus while
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* the previous one is transmitted over MIDI.
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* (The value here is adjusted for midi_ratelimit_per_packet().)
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*/
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p->midi_fifo_limit = rate - MIDI_BYTES_PER_SECOND * s->syt_interval + 1;
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return 0;
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}
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EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters);
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/**
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* amdtp_am824_set_pcm_position - set an index of data channel for a channel
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* of PCM frame
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* @s: the AMDTP stream
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* @index: the index of data channel in an data block
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* @position: the channel of PCM frame
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*/
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void amdtp_am824_set_pcm_position(struct amdtp_stream *s, unsigned int index,
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unsigned int position)
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{
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struct amdtp_am824 *p = s->protocol;
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if (index < p->pcm_channels)
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p->pcm_positions[index] = position;
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}
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EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_position);
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/**
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* amdtp_am824_set_midi_position - set a index of data channel for MIDI
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* conformant data channel
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* @s: the AMDTP stream
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* @position: the index of data channel in an data block
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*/
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void amdtp_am824_set_midi_position(struct amdtp_stream *s,
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unsigned int position)
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{
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struct amdtp_am824 *p = s->protocol;
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p->midi_position = position;
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}
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EXPORT_SYMBOL_GPL(amdtp_am824_set_midi_position);
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static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
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__be32 *buffer, unsigned int frames,
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unsigned int pcm_frames)
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{
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struct amdtp_am824 *p = s->protocol;
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unsigned int channels = p->pcm_channels;
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struct snd_pcm_runtime *runtime = pcm->runtime;
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unsigned int pcm_buffer_pointer;
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int remaining_frames;
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const u32 *src;
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int i, c;
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pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
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pcm_buffer_pointer %= runtime->buffer_size;
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src = (void *)runtime->dma_area +
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frames_to_bytes(runtime, pcm_buffer_pointer);
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remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
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for (i = 0; i < frames; ++i) {
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for (c = 0; c < channels; ++c) {
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buffer[p->pcm_positions[c]] =
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cpu_to_be32((*src >> 8) | 0x40000000);
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src++;
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}
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buffer += s->data_block_quadlets;
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if (--remaining_frames == 0)
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src = (void *)runtime->dma_area;
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}
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}
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static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
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__be32 *buffer, unsigned int frames,
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unsigned int pcm_frames)
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{
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struct amdtp_am824 *p = s->protocol;
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unsigned int channels = p->pcm_channels;
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struct snd_pcm_runtime *runtime = pcm->runtime;
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unsigned int pcm_buffer_pointer;
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int remaining_frames;
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u32 *dst;
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int i, c;
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pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
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pcm_buffer_pointer %= runtime->buffer_size;
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dst = (void *)runtime->dma_area +
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frames_to_bytes(runtime, pcm_buffer_pointer);
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remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
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for (i = 0; i < frames; ++i) {
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for (c = 0; c < channels; ++c) {
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*dst = be32_to_cpu(buffer[p->pcm_positions[c]]) << 8;
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dst++;
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}
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buffer += s->data_block_quadlets;
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if (--remaining_frames == 0)
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dst = (void *)runtime->dma_area;
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}
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}
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static void write_pcm_silence(struct amdtp_stream *s,
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__be32 *buffer, unsigned int frames)
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{
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struct amdtp_am824 *p = s->protocol;
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unsigned int i, c, channels = p->pcm_channels;
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for (i = 0; i < frames; ++i) {
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for (c = 0; c < channels; ++c)
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buffer[p->pcm_positions[c]] = cpu_to_be32(0x40000000);
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buffer += s->data_block_quadlets;
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}
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}
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/**
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* amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream
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* @s: the AMDTP stream for AM824 data block, must be initialized.
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* @runtime: the PCM substream runtime
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*
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*/
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int amdtp_am824_add_pcm_hw_constraints(struct amdtp_stream *s,
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struct snd_pcm_runtime *runtime)
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{
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int err;
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err = amdtp_stream_add_pcm_hw_constraints(s, runtime);
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if (err < 0)
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return err;
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/* AM824 in IEC 61883-6 can deliver 24bit data. */
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return snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
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}
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EXPORT_SYMBOL_GPL(amdtp_am824_add_pcm_hw_constraints);
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/**
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* amdtp_am824_midi_trigger - start/stop playback/capture with a MIDI device
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* @s: the AMDTP stream
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* @port: index of MIDI port
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* @midi: the MIDI device to be started, or %NULL to stop the current device
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*
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* Call this function on a running isochronous stream to enable the actual
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* transmission of MIDI data. This function should be called from the MIDI
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* device's .trigger callback.
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*/
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void amdtp_am824_midi_trigger(struct amdtp_stream *s, unsigned int port,
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struct snd_rawmidi_substream *midi)
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{
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struct amdtp_am824 *p = s->protocol;
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if (port < p->midi_ports)
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WRITE_ONCE(p->midi[port], midi);
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}
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EXPORT_SYMBOL_GPL(amdtp_am824_midi_trigger);
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/*
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* To avoid sending MIDI bytes at too high a rate, assume that the receiving
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* device has a FIFO, and track how much it is filled. This values increases
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* by one whenever we send one byte in a packet, but the FIFO empties at
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* a constant rate independent of our packet rate. One packet has syt_interval
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* samples, so the number of bytes that empty out of the FIFO, per packet(!),
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* is MIDI_BYTES_PER_SECOND * syt_interval / sample_rate. To avoid storing
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* fractional values, the values in midi_fifo_used[] are measured in bytes
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* multiplied by the sample rate.
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*/
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static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
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{
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struct amdtp_am824 *p = s->protocol;
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int used;
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used = p->midi_fifo_used[port];
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if (used == 0) /* common shortcut */
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return true;
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used -= MIDI_BYTES_PER_SECOND * s->syt_interval;
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used = max(used, 0);
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p->midi_fifo_used[port] = used;
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return used < p->midi_fifo_limit;
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}
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static void midi_rate_use_one_byte(struct amdtp_stream *s, unsigned int port)
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{
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struct amdtp_am824 *p = s->protocol;
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p->midi_fifo_used[port] += amdtp_rate_table[s->sfc];
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}
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static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer,
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unsigned int frames, unsigned int data_block_counter)
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{
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struct amdtp_am824 *p = s->protocol;
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unsigned int f, port;
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u8 *b;
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for (f = 0; f < frames; f++) {
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b = (u8 *)&buffer[p->midi_position];
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port = (data_block_counter + f) % 8;
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if (f < MAX_MIDI_RX_BLOCKS &&
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midi_ratelimit_per_packet(s, port) &&
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p->midi[port] != NULL &&
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snd_rawmidi_transmit(p->midi[port], &b[1], 1) == 1) {
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midi_rate_use_one_byte(s, port);
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b[0] = 0x81;
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} else {
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b[0] = 0x80;
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b[1] = 0;
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}
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b[2] = 0;
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b[3] = 0;
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buffer += s->data_block_quadlets;
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}
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}
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static void read_midi_messages(struct amdtp_stream *s, __be32 *buffer,
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unsigned int frames, unsigned int data_block_counter)
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{
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struct amdtp_am824 *p = s->protocol;
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int len;
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u8 *b;
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int f;
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for (f = 0; f < frames; f++) {
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unsigned int port = f;
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if (!(s->flags & CIP_UNALIGHED_DBC))
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port += data_block_counter;
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port %= 8;
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b = (u8 *)&buffer[p->midi_position];
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len = b[0] - 0x80;
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if ((1 <= len) && (len <= 3) && (p->midi[port]))
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snd_rawmidi_receive(p->midi[port], b + 1, len);
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buffer += s->data_block_quadlets;
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}
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}
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static unsigned int process_it_ctx_payloads(struct amdtp_stream *s,
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const struct pkt_desc *descs,
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unsigned int packets,
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struct snd_pcm_substream *pcm)
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{
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struct amdtp_am824 *p = s->protocol;
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unsigned int pcm_frames = 0;
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int i;
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for (i = 0; i < packets; ++i) {
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const struct pkt_desc *desc = descs + i;
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__be32 *buf = desc->ctx_payload;
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unsigned int data_blocks = desc->data_blocks;
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if (pcm) {
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write_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
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pcm_frames += data_blocks * p->frame_multiplier;
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} else {
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write_pcm_silence(s, buf, data_blocks);
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}
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if (p->midi_ports) {
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write_midi_messages(s, buf, data_blocks,
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desc->data_block_counter);
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}
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}
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return pcm_frames;
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}
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static unsigned int process_ir_ctx_payloads(struct amdtp_stream *s,
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const struct pkt_desc *descs,
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unsigned int packets,
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struct snd_pcm_substream *pcm)
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{
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struct amdtp_am824 *p = s->protocol;
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unsigned int pcm_frames = 0;
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int i;
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for (i = 0; i < packets; ++i) {
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const struct pkt_desc *desc = descs + i;
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__be32 *buf = desc->ctx_payload;
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unsigned int data_blocks = desc->data_blocks;
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if (pcm) {
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read_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
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pcm_frames += data_blocks * p->frame_multiplier;
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}
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if (p->midi_ports) {
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read_midi_messages(s, buf, data_blocks,
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desc->data_block_counter);
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}
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}
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return pcm_frames;
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}
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/**
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* amdtp_am824_init - initialize an AMDTP stream structure to handle AM824
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* data block
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* @s: the AMDTP stream to initialize
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* @unit: the target of the stream
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* @dir: the direction of stream
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* @flags: the packet transmission method to use
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*/
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int amdtp_am824_init(struct amdtp_stream *s, struct fw_unit *unit,
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enum amdtp_stream_direction dir, enum cip_flags flags)
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{
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amdtp_stream_process_ctx_payloads_t process_ctx_payloads;
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if (dir == AMDTP_IN_STREAM)
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process_ctx_payloads = process_ir_ctx_payloads;
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else
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process_ctx_payloads = process_it_ctx_payloads;
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return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
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process_ctx_payloads, sizeof(struct amdtp_am824));
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}
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EXPORT_SYMBOL_GPL(amdtp_am824_init);
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