sound/firewire/tascam/amdtp-tascam.c

   1 /*
   2  * amdtp-tascam.c - a part of driver for TASCAM FireWire series
   3  *
   4  * Copyright (c) 2015 Takashi Sakamoto
   5  *
   6  * Licensed under the terms of the GNU General Public License, version 2.
   7  */
   8
   9 #include <sound/pcm.h>
  10 #include "tascam.h"
  11
  12 #define AMDTP_FMT_TSCM_TX       0x1e
  13 #define AMDTP_FMT_TSCM_RX       0x3e
  14
  15 struct amdtp_tscm {
  16         unsigned int pcm_channels;
  17 };
  18
  19 int amdtp_tscm_set_parameters(struct amdtp_stream *s, unsigned int rate)
  20 {
  21         struct amdtp_tscm *p = s->protocol;
  22         unsigned int data_channels;
  23
  24         if (amdtp_stream_running(s))
  25                 return -EBUSY;
  26
  27         data_channels = p->pcm_channels;
  28
  29         /* Packets in in-stream have extra 2 data channels. */
  30         if (s->direction == AMDTP_IN_STREAM)
  31                 data_channels += 2;
  32
  33         return amdtp_stream_set_parameters(s, rate, data_channels);
  34 }
  35
  36 static void write_pcm_s32(struct amdtp_stream *s,
  37                           struct snd_pcm_substream *pcm,
  38                           __be32 *buffer, unsigned int frames)
  39 {
  40         struct amdtp_tscm *p = s->protocol;
  41         struct snd_pcm_runtime *runtime = pcm->runtime;
  42         unsigned int channels, remaining_frames, i, c;
  43         const u32 *src;
  44
  45         channels = p->pcm_channels;
  46         src = (void *)runtime->dma_area +
  47                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
  48         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
  49
  50         for (i = 0; i < frames; ++i) {
  51                 for (c = 0; c < channels; ++c) {
  52                         buffer[c] = cpu_to_be32(*src);
  53                         src++;
  54                 }
  55                 buffer += s->data_block_quadlets;
  56                 if (--remaining_frames == 0)
  57                         src = (void *)runtime->dma_area;
  58         }
  59 }
  60
  61 static void read_pcm_s32(struct amdtp_stream *s,
  62                          struct snd_pcm_substream *pcm,
  63                          __be32 *buffer, unsigned int frames)
  64 {
  65         struct amdtp_tscm *p = s->protocol;
  66         struct snd_pcm_runtime *runtime = pcm->runtime;
  67         unsigned int channels, remaining_frames, i, c;
  68         u32 *dst;
  69
  70         channels = p->pcm_channels;
  71         dst  = (void *)runtime->dma_area +
  72                         frames_to_bytes(runtime, s->pcm_buffer_pointer);
  73         remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
  74
  75         /* The first data channel is for event counter. */
  76         buffer += 1;
  77
  78         for (i = 0; i < frames; ++i) {
  79                 for (c = 0; c < channels; ++c) {
  80                         *dst = be32_to_cpu(buffer[c]);
  81                         dst++;
  82                 }
  83                 buffer += s->data_block_quadlets;
  84                 if (--remaining_frames == 0)
  85                         dst = (void *)runtime->dma_area;
  86         }
  87 }
  88
  89 static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer,
  90                               unsigned int data_blocks)
  91 {
  92         struct amdtp_tscm *p = s->protocol;
  93         unsigned int channels, i, c;
  94
  95         channels = p->pcm_channels;
  96
  97         for (i = 0; i < data_blocks; ++i) {
  98                 for (c = 0; c < channels; ++c)
  99                         buffer[c] = 0x00000000;
 100                 buffer += s->data_block_quadlets;
 101         }
 102 }
 103
 104 int amdtp_tscm_add_pcm_hw_constraints(struct amdtp_stream *s,
 105                                       struct snd_pcm_runtime *runtime)
 106 {
 107         int err;
 108
 109         /*
 110          * Our implementation allows this protocol to deliver 24 bit sample in
 111          * 32bit data channel.
 112          */
 113         err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
 114         if (err < 0)
 115                 return err;
 116
 117         return amdtp_stream_add_pcm_hw_constraints(s, runtime);
 118 }
 119
 120 static unsigned int process_tx_data_blocks(struct amdtp_stream *s,
 121                                            __be32 *buffer,
 122                                            unsigned int data_blocks,
 123                                            unsigned int *syt)
 124 {
 125         struct snd_pcm_substream *pcm;
 126
 127         pcm = READ_ONCE(s->pcm);
 128         if (data_blocks > 0 && pcm)
 129                 read_pcm_s32(s, pcm, buffer, data_blocks);
 130
 131         /* A place holder for control messages. */
 132
 133         return data_blocks;
 134 }
 135
 136 static unsigned int process_rx_data_blocks(struct amdtp_stream *s,
 137                                            __be32 *buffer,
 138                                            unsigned int data_blocks,
 139                                            unsigned int *syt)
 140 {
 141         struct snd_pcm_substream *pcm;
 142
 143         /* This field is not used. */
 144         *syt = 0x0000;
 145
 146         pcm = READ_ONCE(s->pcm);
 147         if (pcm)
 148                 write_pcm_s32(s, pcm, buffer, data_blocks);
 149         else
 150                 write_pcm_silence(s, buffer, data_blocks);
 151
 152         return data_blocks;
 153 }
 154
 155 int amdtp_tscm_init(struct amdtp_stream *s, struct fw_unit *unit,
 156                     enum amdtp_stream_direction dir, unsigned int pcm_channels)
 157 {
 158         amdtp_stream_process_data_blocks_t process_data_blocks;
 159         struct amdtp_tscm *p;
 160         unsigned int fmt;
 161         int err;
 162
 163         if (dir == AMDTP_IN_STREAM) {
 164                 fmt = AMDTP_FMT_TSCM_TX;
 165                 process_data_blocks = process_tx_data_blocks;
 166         } else {
 167                 fmt = AMDTP_FMT_TSCM_RX;
 168                 process_data_blocks = process_rx_data_blocks;
 169         }
 170
 171         err = amdtp_stream_init(s, unit, dir,
 172                                 CIP_NONBLOCKING | CIP_SKIP_DBC_ZERO_CHECK, fmt,
 173                                 process_data_blocks, sizeof(struct amdtp_tscm));
 174         if (err < 0)
 175                 return 0;
 176
 177         /* Use fixed value for FDF field. */
 178         s->fdf = 0x00;
 179
 180         /* This protocol uses fixed number of data channels for PCM samples. */
 181         p = s->protocol;
 182         p->pcm_channels = pcm_channels;
 183
 184         return 0;
 185 }