Kernel-2.6.32-573.12.1.el6_hdsp

Software Interface ALSA-DSP MADI Driver

(translated from German, so no good English ;-),
2004 - winfried ritsch

Full functionality has been added to the driver. Since some of
the Controls and startup-options are ALSA-Standard and only the
special Controls are described and discussed below.

hardware functionality:

Audio transmission:

 number of channels --  depends on transmission mode

    The number of channels chosen is from 1..Nmax. The reason to
    use for a lower number of channels is only resource allocation,
    since unused DMA channels are disabled and less memory is
    allocated. So also the throughput of the PCI system can be
    scaled. (Only important for low performance boards).

   Single Speed -- 1..64 channels 

     (Note: Choosing the 56channel mode for transmission or as
     receiver, only 56 are transmitted/received over the MADI, but
     all 64 channels are available for the mixer, so channel count
     for the driver)

   Double Speed -- 1..32 channels

     Note: Choosing the 56-channel mode for
     transmission/receive-mode , only 28 are transmitted/received
     over the MADI, but all 32 channels are available for the mixer,
     so channel count for the driver


   Quad Speed -- 1..16 channels 

     Note: Choosing the 56-channel mode for
     transmission/receive-mode , only 14 are transmitted/received
     over the MADI, but all 16 channels are available for the mixer,
     so channel count for the driver

 Format -- signed 32 Bit Little Endian (SNDRV_PCM_FMTBIT_S32_LE)

 Sample Rates --

   Single Speed -- 32000, 44100, 48000

   Double Speed -- 64000, 88200, 96000 (untested)

   Quad Speed -- 128000, 176400, 192000 (untested)

 access-mode -- MMAP (memory mapped), Not interleaved
 (PCM_NON-INTERLEAVED)

 buffer-sizes -- 64,128,256,512,1024,2048,8192 Samples

 fragments -- 2

 Hardware-pointer -- 2 Modi


     The Card supports the readout of the actual Buffer-pointer,
     where DMA reads/writes. Since of the bulk mode of PCI it is only
     64 Byte accurate. SO it is not really usable for the
     ALSA-mid-level functions (here the buffer-ID gives a better
     result), but if MMAP is used by the application. Therefore it
     can be configured at load-time with the parameter
     precise-pointer.


     (Hint: Experimenting I found that the pointer is maximum 64 to
     large never to small. So if you subtract 64 you always have a
     safe pointer for writing, which is used on this mode inside
     ALSA. In theory now you can get now a latency as low as 16
     Samples, which is a quarter of the interrupt possibilities.)

   Precise Pointer -- off
                interrupt used for pointer-calculation

   Precise Pointer -- on
                hardware pointer used.

Controller:

  Since DSP-MADI-Mixer has 8152 Fader, it does not make sense to
  use the standard mixer-controls, since this would break most of
  (especially graphic) ALSA-Mixer GUIs. So Mixer control has be
  provided by a 2-dimensional controller using the
  hwdep-interface. 

 Also all 128+256 Peak and RMS-Meter can be accessed via the
 hwdep-interface. Since it could be a performance problem always
 copying and converting Peak and RMS-Levels even if you just need
 one, I decided to export the hardware structure, so that of
 needed some driver-guru can implement a memory-mapping of mixer
 or peak-meters over ioctl, or also to do only copying and no
 conversion. A test-application shows the usage of the controller.

Latency Controls --- not implemented !!!


   Note: Within the windows-driver the latency is accessible of a
   control-panel, but buffer-sizes are controlled with ALSA from
   hwparams-calls and should not be changed in run-state, I did not
   implement it here.


System Clock -- suspended !!!!

    Name -- "System Clock Mode"

    Access -- Read Write

    Values -- "Master" "Slave"


      !!!! This is a hardware-function but is in conflict with the
      Clock-source controller, which is a kind of ALSA-standard. I
      makes sense to set the card to a special mode (master at some
      frequency or slave), since even not using an Audio-application
      a studio should have working synchronisations setup. So use
      Clock-source-controller instead !!!!

Clock Source  

   Name -- "Sample Clock Source"

   Access -- Read Write

   Values -- "AutoSync", "Internal 32.0 kHz", "Internal 44.1 kHz",
   "Internal 48.0 kHz", "Internal 64.0 kHz", "Internal 88.2 kHz",
   "Internal 96.0 kHz"

     Choose between Master at a specific Frequency and so also the
     Speed-mode or Slave (Autosync). Also see  "Preferred Sync Ref"


   !!!! This is no pure hardware function but was implemented by
   ALSA by some ALSA-drivers before, so I use it also. !!!


Preferred Sync Ref

   Name -- "Preferred Sync Reference"

   Access -- Read Write

   Values -- "Word" "MADI"


     Within the Auto-sync-Mode the preferred Sync Source can be
     chosen. If it is not available another is used if possible.

     Note: Since MADI has a much higher bit-rate than word-clock, the
     card should synchronise better in MADI Mode. But since the
     RME-PLL is very good, there are almost no problems with
     word-clock too. I never found a difference.


TX 64 channel --- 

   Name -- "TX 64 channels mode"

   Access -- Read Write

   Values -- 0 1

     Using 64-channel-modus (1) or 56-channel-modus for
     MADI-transmission (0).


     Note: This control is for output only. Input-mode is detected
     automatically from hardware sending MADI.


Clear TMS ---

   Name -- "Clear Track Marker"

   Access -- Read Write

   Values -- 0 1


     Don't use to lower 5 Audio-bits on AES as additional Bits.
    

Safe Mode oder Auto Input --- 

   Name -- "Safe Mode"

   Access -- Read Write

   Values -- 0 1

   (default on)

     If on (1), then if either the optical or coaxial connection
     has a failure, there is a takeover to the working one, with no
     sample failure. Its only useful if you use the second as a
     backup connection.

Input --- 

   Name -- "Input Select"

   Access -- Read Write

   Values -- optical coaxial


     Choosing the Input, optical or coaxial. If Safe-mode is active,
     this is the preferred Input.

————– Mixer ———————-

Mixer

   Name -- "Mixer"

   Access -- Read Write

   Values - <channel-number 0-127> <Value 0-65535>


     Here as a first value the channel-index is taken to get/set the
     corresponding mixer channel, where 0-63 are the input to output
     fader and 64-127 the playback to outputs fader. Value 0
     is channel muted 0 and 32768 an amplification of  1.

Chn 1-64

   fast mixer for the ALSA-mixer utils. The diagonal of the
   mixer-matrix is implemented from playback to output.
   

Line Out

   Name  -- "Line Out"

   Access -- Read Write

   Values -- 0 1

     Switching on and off the analog out, which has nothing to do
     with mixing or routing. the analog outs reflects channel 63,64.

— information (only read access):

Sample Rate

   Name -- "System Sample Rate"

   Access -- Read-only

     getting the sample rate.


External Rate measured

   Name -- "External Rate"

   Access -- Read only


     Should be "Autosync Rate", but Name used is
     ALSA-Scheme. External Sample frequency liked used on Autosync is
     reported.


MADI Sync Status

   Name -- "MADI Sync Lock Status"

   Access -- Read

   Values -- 0,1,2

   MADI-Input is 0=Unlocked, 1=Locked, or 2=Synced.


Word Clock Sync Status

   Name -- "Word Clock Lock Status"

   Access -- Read

   Values -- 0,1,2

   Word Clock Input is 0=Unlocked, 1=Locked, or 2=Synced.

AutoSync

   Name -- "AutoSync Reference"

   Access -- Read

   Values -- "WordClock", "MADI", "None"

     Sync-Reference is either "WordClock", "MADI" or none.

RX 64ch — noch nicht implementiert

   MADI-Receiver is in 64 channel mode oder 56 channel mode.

AB_inp — not tested

     Used input for Auto-Input.

actual Buffer Position — not implemented

   !!! this is a ALSA internal function, so no control is used !!!

Calling Parameter:

index int array (min = 1, max = 8),
“Index value for RME HDSPM interface.” card-index within ALSA

 note: ALSA-standard

id string array (min = 1, max = 8),
“ID string for RME HDSPM interface.”

 note: ALSA-standard

enable int array (min = 1, max = 8),
“Enable/disable specific HDSPM sound-cards.”

 note: ALSA-standard

precise_ptr int array (min = 1, max = 8),
“Enable precise pointer, or disable.”

 note: Use only when the application supports this (which is a special case).

line_outs_monitor int array (min = 1, max = 8),
“Send playback streams to analog outs by default.”

  note: each playback channel is mixed to the same numbered output
  channel (routed). This is against the ALSA-convention, where all
  channels have to be muted on after loading the driver, but was
  used before on other cards, so i historically use it again)

enable_monitor int array (min = 1, max = 8),
“Enable Analog Out on Channel 63/64 by default.”

  note: here the analog output is enabled (but not routed).