sound/firewire/digi00x/amdtp-dot.c

   1 /*
   2  * amdtp-dot.c - a part of driver for Digidesign Digi 002/003 family
   3  *
   4  * Copyright (c) 2014-2015 Takashi Sakamoto
   5  * Copyright (C) 2012 Robin Gareus <robin@gareus.org>
   6  * Copyright (C) 2012 Damien Zammit <damien@zamaudio.com>
   7  *
   8  * Licensed under the terms of the GNU General Public License, version 2.
   9  */
  10
  11 #include <sound/pcm.h>
  12 #include "digi00x.h"
  13
  14 #define CIP_FMT_AM              0x10
  15
  16 /* 'Clock-based rate control mode' is just supported. */
  17 #define AMDTP_FDF_AM824         0x00
  18
  19 /*
  20  * The double-oh-three algorithm was discovered by Robin Gareus and Damien
  21  * Zammit in 2012, with reverse-engineering for Digi 003 Rack.
  22  */
  23 struct dot_state {
  24         __u8 carry;
  25         __u8 idx;
  26         unsigned int off;
  27 };
  28
  29 struct amdtp_dot {
  30         unsigned int pcm_channels;
  31         struct dot_state state;
  32
  33         unsigned int midi_ports;
  34
  35         void (*transfer_samples)(struct amdtp_stream *s,
  36                                  struct snd_pcm_substream *pcm,
  37                                  __be32 *buffer, unsigned int frames);
  38 };
  39
  40 /*
  41  * double-oh-three look up table
  42  *
  43  * @param idx index byte (audio-sample data) 0x00..0xff
  44  * @param off channel offset shift
  45  * @return salt to XOR with given data
  46  */
  47 #define BYTE_PER_SAMPLE (4)
  48 #define MAGIC_DOT_BYTE (2)
  49 #define MAGIC_BYTE_OFF(x) (((x) * BYTE_PER_SAMPLE) + MAGIC_DOT_BYTE)
  50 static const __u8 dot_scrt(const __u8 idx, const unsigned int off)
  51 {
  52         /*
  53          * the length of the added pattern only depends on the lower nibble
  54          * of the last non-zero data
  55          */
  56         static const __u8 len[16] = {0, 1, 3, 5, 7, 9, 11, 13, 14,
  57                                      12, 10, 8, 6, 4, 2, 0};
  58
  59         /*
  60          * the lower nibble of the salt. Interleaved sequence.
  61          * this is walked backwards according to len[]
  62          */
  63         static const __u8 nib[15] = {0x8, 0x7, 0x9, 0x6, 0xa, 0x5, 0xb, 0x4,
  64                                      0xc, 0x3, 0xd, 0x2, 0xe, 0x1, 0xf};
  65
  66         /* circular list for the salt's hi nibble. */
  67         static const __u8 hir[15] = {0x0, 0x6, 0xf, 0x8, 0x7, 0x5, 0x3, 0x4,
  68                                      0xc, 0xd, 0xe, 0x1, 0x2, 0xb, 0xa};
  69
  70         /*
  71          * start offset for upper nibble mapping.
  72          * note: 9 is /special/. In the case where the high nibble == 0x9,
  73          * hir[] is not used and - coincidentally - the salt's hi nibble is
  74          * 0x09 regardless of the offset.
  75          */
  76         static const __u8 hio[16] = {0, 11, 12, 6, 7, 5, 1, 4,
  77                                      3, 0x00, 14, 13, 8, 9, 10, 2};
  78
  79         const __u8 ln = idx & 0xf;
  80         const __u8 hn = (idx >> 4) & 0xf;
  81         const __u8 hr = (hn == 0x9) ? 0x9 : hir[(hio[hn] + off) % 15];
  82
  83         if (len[ln] < off)
  84                 return 0x00;
  85
  86         return ((nib[14 + off - len[ln]]) | (hr << 4));
  87 }
  88
  89 static void dot_encode_step(struct dot_state *state, __be32 *const buffer)
  90 {
  91         __u8 * const data = (__u8 *) buffer;
  92
  93         if (data[MAGIC_DOT_BYTE] != 0x00) {
  94                 state->off = 0;
  95                 state->idx = data[MAGIC_DOT_BYTE] ^ state->carry;
  96         }
  97         data[MAGIC_DOT_BYTE] ^= state->carry;
  98         state->carry = dot_scrt(state->idx, ++(state->off));
  99 }
 100
 101 int amdtp_dot_set_parameters(struct amdtp_stream *s, unsigned int rate,
 102                              unsigned int pcm_channels, unsigned int midi_ports)
 103 {
 104         struct amdtp_dot *p = s->protocol;
 105         int err;
 106
 107         if (amdtp_stream_running(s))
 108                 return -EBUSY;
 109
 110         /*
 111          * A first data channel is for MIDI conformant data channel, the rest is
 112          * Multi Bit Linear Audio data channel.
 113          */
 114         err = amdtp_stream_set_parameters(s, rate, pcm_channels + 1);
 115         if (err < 0)
 116                 return err;
 117
 118         s->fdf = AMDTP_FDF_AM824 | s->sfc;
 119
 120         p->pcm_channels = pcm_channels;
 121         p->midi_ports = midi_ports;
 122
 123         return 0;
 124 }
 125
 126 static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
 127                           __be32 *buffer, unsigned int frames)
 128 {
 129         struct amdtp_dot *p = s->protocol;
 130         struct snd_pcm_runtime *runtime = pcm->runtime;
 131         unsigned int channels, remaining_frames, i, c;
 132         const u32 *src;
 133
 134         channels = p->pcm_channels;
 135         src = (void *)runtime->dma_area +
 136                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
 137         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 138
 139         buffer++;
 140         for (i = 0; i < frames; ++i) {
 141                 for (c = 0; c < channels; ++c) {
 142                         buffer[c] = cpu_to_be32((*src >> 8) | 0x40000000);
 143                         dot_encode_step(&p->state, &buffer[c]);
 144                         src++;
 145                 }
 146                 buffer += s->data_block_quadlets;
 147                 if (--remaining_frames == 0)
 148                         src = (void *)runtime->dma_area;
 149         }
 150 }
 151
 152 static void write_pcm_s16(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
 153                           __be32 *buffer, unsigned int frames)
 154 {
 155         struct amdtp_dot *p = s->protocol;
 156         struct snd_pcm_runtime *runtime = pcm->runtime;
 157         unsigned int channels, remaining_frames, i, c;
 158         const u16 *src;
 159
 160         channels = p->pcm_channels;
 161         src = (void *)runtime->dma_area +
 162                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
 163         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 164
 165         buffer++;
 166         for (i = 0; i < frames; ++i) {
 167                 for (c = 0; c < channels; ++c) {
 168                         buffer[c] = cpu_to_be32((*src << 8) | 0x40000000);
 169                         dot_encode_step(&p->state, &buffer[c]);
 170                         src++;
 171                 }
 172                 buffer += s->data_block_quadlets;
 173                 if (--remaining_frames == 0)
 174                         src = (void *)runtime->dma_area;
 175         }
 176 }
 177
 178 static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
 179                          __be32 *buffer, unsigned int frames)
 180 {
 181         struct amdtp_dot *p = s->protocol;
 182         struct snd_pcm_runtime *runtime = pcm->runtime;
 183         unsigned int channels, remaining_frames, i, c;
 184         u32 *dst;
 185
 186         channels = p->pcm_channels;
 187         dst  = (void *)runtime->dma_area +
 188                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
 189         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 190
 191         buffer++;
 192         for (i = 0; i < frames; ++i) {
 193                 for (c = 0; c < channels; ++c) {
 194                         *dst = be32_to_cpu(buffer[c]) << 8;
 195                         dst++;
 196                 }
 197                 buffer += s->data_block_quadlets;
 198                 if (--remaining_frames == 0)
 199                         dst = (void *)runtime->dma_area;
 200         }
 201 }
 202
 203 static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer,
 204                               unsigned int data_blocks)
 205 {
 206         struct amdtp_dot *p = s->protocol;
 207         unsigned int channels, i, c;
 208
 209         channels = p->pcm_channels;
 210
 211         buffer++;
 212         for (i = 0; i < data_blocks; ++i) {
 213                 for (c = 0; c < channels; ++c)
 214                         buffer[c] = cpu_to_be32(0x40000000);
 215                 buffer += s->data_block_quadlets;
 216         }
 217 }
 218
 219 int amdtp_dot_add_pcm_hw_constraints(struct amdtp_stream *s,
 220                                      struct snd_pcm_runtime *runtime)
 221 {
 222         int err;
 223
 224         /* This protocol delivers 24 bit data in 32bit data channel. */
 225         err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
 226         if (err < 0)
 227                 return err;
 228
 229         return amdtp_stream_add_pcm_hw_constraints(s, runtime);
 230 }
 231
 232 void amdtp_dot_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format)
 233 {
 234         struct amdtp_dot *p = s->protocol;
 235
 236         if (WARN_ON(amdtp_stream_pcm_running(s)))
 237                 return;
 238
 239         switch (format) {
 240         default:
 241                 WARN_ON(1);
 242                 /* fall through */
 243         case SNDRV_PCM_FORMAT_S16:
 244                 if (s->direction == AMDTP_OUT_STREAM) {
 245                         p->transfer_samples = write_pcm_s16;
 246                         break;
 247                 }
 248                 WARN_ON(1);
 249                 /* fall through */
 250         case SNDRV_PCM_FORMAT_S32:
 251                 if (s->direction == AMDTP_OUT_STREAM)
 252                         p->transfer_samples = write_pcm_s32;
 253                 else
 254                         p->transfer_samples = read_pcm_s32;
 255                 break;
 256         }
 257 }
 258
 259 static unsigned int process_tx_data_blocks(struct amdtp_stream *s,
 260                                            __be32 *buffer,
 261                                            unsigned int data_blocks,
 262                                            unsigned int *syt)
 263 {
 264         struct amdtp_dot *p = (struct amdtp_dot *)s->protocol;
 265         struct snd_pcm_substream *pcm;
 266         unsigned int pcm_frames;
 267
 268         pcm = ACCESS_ONCE(s->pcm);
 269         if (pcm) {
 270                 p->transfer_samples(s, pcm, buffer, data_blocks);
 271                 pcm_frames = data_blocks;
 272         } else {
 273                 pcm_frames = 0;
 274         }
 275
 276         /* A place holder for MIDI processing. */
 277
 278         return pcm_frames;
 279 }
 280
 281 static unsigned int process_rx_data_blocks(struct amdtp_stream *s,
 282                                            __be32 *buffer,
 283                                            unsigned int data_blocks,
 284                                            unsigned int *syt)
 285 {
 286         struct amdtp_dot *p = (struct amdtp_dot *)s->protocol;
 287         struct snd_pcm_substream *pcm;
 288         unsigned int pcm_frames;
 289
 290         pcm = ACCESS_ONCE(s->pcm);
 291         if (pcm) {
 292                 p->transfer_samples(s, pcm, buffer, data_blocks);
 293                 pcm_frames = data_blocks;
 294         } else {
 295                 write_pcm_silence(s, buffer, data_blocks);
 296                 pcm_frames = 0;
 297         }
 298
 299         /* A place holder for MIDI processing. */
 300
 301         return pcm_frames;
 302 }
 303
 304 int amdtp_dot_init(struct amdtp_stream *s, struct fw_unit *unit,
 305                  enum amdtp_stream_direction dir)
 306 {
 307         amdtp_stream_process_data_blocks_t process_data_blocks;
 308         enum cip_flags flags;
 309
 310         /* Use different mode between incoming/outgoing. */
 311         if (dir == AMDTP_IN_STREAM) {
 312                 flags = CIP_NONBLOCKING | CIP_SKIP_INIT_DBC_CHECK;
 313                 process_data_blocks = process_tx_data_blocks;
 314         } else {
 315                 flags = CIP_BLOCKING;
 316                 process_data_blocks = process_rx_data_blocks;
 317         }
 318
 319         return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM,
 320                                  process_data_blocks, sizeof(struct amdtp_dot));
 321 }
 322
 323 void amdtp_dot_reset(struct amdtp_stream *s)
 324 {
 325         struct amdtp_dot *p = s->protocol;
 326
 327         p->state.carry = 0x00;
 328         p->state.idx = 0x00;
 329         p->state.off = 0;
 330 }