summaryrefslogtreecommitdiffstats
path: root/sound/firewire/digi00x/amdtp-dot.c
diff options
context:
space:
mode:
Diffstat (limited to 'sound/firewire/digi00x/amdtp-dot.c')
-rw-r--r--sound/firewire/digi00x/amdtp-dot.c418
1 files changed, 418 insertions, 0 deletions
diff --git a/sound/firewire/digi00x/amdtp-dot.c b/sound/firewire/digi00x/amdtp-dot.c
new file mode 100644
index 000000000..59b86c8d8
--- /dev/null
+++ b/sound/firewire/digi00x/amdtp-dot.c
@@ -0,0 +1,418 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * amdtp-dot.c - a part of driver for Digidesign Digi 002/003 family
+ *
+ * Copyright (c) 2014-2015 Takashi Sakamoto
+ * Copyright (C) 2012 Robin Gareus <robin@gareus.org>
+ * Copyright (C) 2012 Damien Zammit <damien@zamaudio.com>
+ */
+
+#include <sound/pcm.h>
+#include "digi00x.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
+
+/* 3 = MAX(DOT_MIDI_IN_PORTS, DOT_MIDI_OUT_PORTS) + 1. */
+#define MAX_MIDI_PORTS 3
+
+/*
+ * The double-oh-three algorithm was discovered by Robin Gareus and Damien
+ * Zammit in 2012, with reverse-engineering for Digi 003 Rack.
+ */
+struct dot_state {
+ u8 carry;
+ u8 idx;
+ unsigned int off;
+};
+
+struct amdtp_dot {
+ unsigned int pcm_channels;
+ struct dot_state state;
+
+ struct snd_rawmidi_substream *midi[MAX_MIDI_PORTS];
+ int midi_fifo_used[MAX_MIDI_PORTS];
+ int midi_fifo_limit;
+};
+
+/*
+ * double-oh-three look up table
+ *
+ * @param idx index byte (audio-sample data) 0x00..0xff
+ * @param off channel offset shift
+ * @return salt to XOR with given data
+ */
+#define BYTE_PER_SAMPLE (4)
+#define MAGIC_DOT_BYTE (2)
+#define MAGIC_BYTE_OFF(x) (((x) * BYTE_PER_SAMPLE) + MAGIC_DOT_BYTE)
+static u8 dot_scrt(const u8 idx, const unsigned int off)
+{
+ /*
+ * the length of the added pattern only depends on the lower nibble
+ * of the last non-zero data
+ */
+ static const u8 len[16] = {0, 1, 3, 5, 7, 9, 11, 13, 14,
+ 12, 10, 8, 6, 4, 2, 0};
+
+ /*
+ * the lower nibble of the salt. Interleaved sequence.
+ * this is walked backwards according to len[]
+ */
+ static const u8 nib[15] = {0x8, 0x7, 0x9, 0x6, 0xa, 0x5, 0xb, 0x4,
+ 0xc, 0x3, 0xd, 0x2, 0xe, 0x1, 0xf};
+
+ /* circular list for the salt's hi nibble. */
+ static const u8 hir[15] = {0x0, 0x6, 0xf, 0x8, 0x7, 0x5, 0x3, 0x4,
+ 0xc, 0xd, 0xe, 0x1, 0x2, 0xb, 0xa};
+
+ /*
+ * start offset for upper nibble mapping.
+ * note: 9 is /special/. In the case where the high nibble == 0x9,
+ * hir[] is not used and - coincidentally - the salt's hi nibble is
+ * 0x09 regardless of the offset.
+ */
+ static const u8 hio[16] = {0, 11, 12, 6, 7, 5, 1, 4,
+ 3, 0x00, 14, 13, 8, 9, 10, 2};
+
+ const u8 ln = idx & 0xf;
+ const u8 hn = (idx >> 4) & 0xf;
+ const u8 hr = (hn == 0x9) ? 0x9 : hir[(hio[hn] + off) % 15];
+
+ if (len[ln] < off)
+ return 0x00;
+
+ return ((nib[14 + off - len[ln]]) | (hr << 4));
+}
+
+static void dot_encode_step(struct dot_state *state, __be32 *const buffer)
+{
+ u8 * const data = (u8 *) buffer;
+
+ if (data[MAGIC_DOT_BYTE] != 0x00) {
+ state->off = 0;
+ state->idx = data[MAGIC_DOT_BYTE] ^ state->carry;
+ }
+ data[MAGIC_DOT_BYTE] ^= state->carry;
+ state->carry = dot_scrt(state->idx, ++(state->off));
+}
+
+int amdtp_dot_set_parameters(struct amdtp_stream *s, unsigned int rate,
+ unsigned int pcm_channels)
+{
+ struct amdtp_dot *p = s->protocol;
+ int err;
+
+ if (amdtp_stream_running(s))
+ return -EBUSY;
+
+ /*
+ * A first data channel is for MIDI messages, the rest is Multi Bit
+ * Linear Audio data channel.
+ */
+ err = amdtp_stream_set_parameters(s, rate, pcm_channels + 1);
+ if (err < 0)
+ return err;
+
+ s->ctx_data.rx.fdf = AMDTP_FDF_AM824 | s->sfc;
+
+ p->pcm_channels = 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;
+}
+
+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_dot *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;
+
+ buffer++;
+ for (i = 0; i < frames; ++i) {
+ for (c = 0; c < channels; ++c) {
+ buffer[c] = cpu_to_be32((*src >> 8) | 0x40000000);
+ dot_encode_step(&p->state, &buffer[c]);
+ 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_dot *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;
+
+ buffer++;
+ for (i = 0; i < frames; ++i) {
+ for (c = 0; c < channels; ++c) {
+ *dst = be32_to_cpu(buffer[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 data_blocks)
+{
+ struct amdtp_dot *p = s->protocol;
+ unsigned int channels, i, c;
+
+ channels = p->pcm_channels;
+
+ buffer++;
+ for (i = 0; i < data_blocks; ++i) {
+ for (c = 0; c < channels; ++c)
+ buffer[c] = cpu_to_be32(0x40000000);
+ buffer += s->data_block_quadlets;
+ }
+}
+
+static bool midi_ratelimit_per_packet(struct amdtp_stream *s, unsigned int port)
+{
+ struct amdtp_dot *p = s->protocol;
+ int used;
+
+ used = p->midi_fifo_used[port];
+ if (used == 0)
+ 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 inline void midi_use_bytes(struct amdtp_stream *s,
+ unsigned int port, unsigned int count)
+{
+ struct amdtp_dot *p = s->protocol;
+
+ p->midi_fifo_used[port] += amdtp_rate_table[s->sfc] * count;
+}
+
+static void write_midi_messages(struct amdtp_stream *s, __be32 *buffer,
+ unsigned int data_blocks, unsigned int data_block_counter)
+{
+ struct amdtp_dot *p = s->protocol;
+ unsigned int f, port;
+ int len;
+ u8 *b;
+
+ for (f = 0; f < data_blocks; f++) {
+ port = (data_block_counter + f) % 8;
+ b = (u8 *)&buffer[0];
+
+ len = 0;
+ if (port < MAX_MIDI_PORTS &&
+ midi_ratelimit_per_packet(s, port) &&
+ p->midi[port] != NULL)
+ len = snd_rawmidi_transmit(p->midi[port], b + 1, 2);
+
+ if (len > 0) {
+ /*
+ * Upper 4 bits of LSB represent port number.
+ * - 0000b: physical MIDI port 1.
+ * - 0010b: physical MIDI port 2.
+ * - 1110b: console MIDI port.
+ */
+ if (port == 2)
+ b[3] = 0xe0;
+ else if (port == 1)
+ b[3] = 0x20;
+ else
+ b[3] = 0x00;
+ b[3] |= len;
+ midi_use_bytes(s, port, len);
+ } else {
+ b[1] = 0;
+ b[2] = 0;
+ b[3] = 0;
+ }
+ b[0] = 0x80;
+
+ buffer += s->data_block_quadlets;
+ }
+}
+
+static void read_midi_messages(struct amdtp_stream *s, __be32 *buffer,
+ unsigned int data_blocks)
+{
+ struct amdtp_dot *p = s->protocol;
+ unsigned int f, port, len;
+ u8 *b;
+
+ for (f = 0; f < data_blocks; f++) {
+ b = (u8 *)&buffer[0];
+
+ len = b[3] & 0x0f;
+ if (len > 0) {
+ /*
+ * Upper 4 bits of LSB represent port number.
+ * - 0000b: physical MIDI port 1. Use port 0.
+ * - 1110b: console MIDI port. Use port 2.
+ */
+ if (b[3] >> 4 > 0)
+ port = 2;
+ else
+ port = 0;
+
+ if (port < MAX_MIDI_PORTS && p->midi[port])
+ snd_rawmidi_receive(p->midi[port], b + 1, len);
+ }
+
+ buffer += s->data_block_quadlets;
+ }
+}
+
+int amdtp_dot_add_pcm_hw_constraints(struct amdtp_stream *s,
+ struct snd_pcm_runtime *runtime)
+{
+ int err;
+
+ /* This protocol delivers 24 bit data in 32bit data channel. */
+ err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
+ if (err < 0)
+ return err;
+
+ return amdtp_stream_add_pcm_hw_constraints(s, runtime);
+}
+
+void amdtp_dot_midi_trigger(struct amdtp_stream *s, unsigned int port,
+ struct snd_rawmidi_substream *midi)
+{
+ struct amdtp_dot *p = s->protocol;
+
+ if (port < MAX_MIDI_PORTS)
+ WRITE_ONCE(p->midi[port], midi);
+}
+
+static unsigned int process_ir_ctx_payloads(struct amdtp_stream *s,
+ const struct pkt_desc *descs,
+ unsigned int packets,
+ struct snd_pcm_substream *pcm)
+{
+ 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;
+ }
+
+ read_midi_messages(s, buf, data_blocks);
+ }
+
+ return pcm_frames;
+}
+
+static unsigned int process_it_ctx_payloads(struct amdtp_stream *s,
+ const struct pkt_desc *descs,
+ unsigned int packets,
+ struct snd_pcm_substream *pcm)
+{
+ 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;
+ } else {
+ write_pcm_silence(s, buf, data_blocks);
+ }
+
+ write_midi_messages(s, buf, data_blocks,
+ desc->data_block_counter);
+ }
+
+ return pcm_frames;
+}
+
+int amdtp_dot_init(struct amdtp_stream *s, struct fw_unit *unit,
+ enum amdtp_stream_direction dir)
+{
+ amdtp_stream_process_ctx_payloads_t process_ctx_payloads;
+ unsigned int flags = CIP_NONBLOCKING | CIP_UNAWARE_SYT;
+
+ // Use different mode between incoming/outgoing.
+ 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_dot));
+}
+
+void amdtp_dot_reset(struct amdtp_stream *s)
+{
+ struct amdtp_dot *p = s->protocol;
+
+ p->state.carry = 0x00;
+ p->state.idx = 0x00;
+ p->state.off = 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-07 23:17:39 +0000