Add documentation for the new MARIAN Seraph M2 sound card. It covers current development status, available controls of the card and information about the integrated loopback.
Signed-off-by: Ivan Orlov ivan.orlov0322@gmail.com --- Documentation/sound/cards/index.rst | 1 + Documentation/sound/cards/marian-m2.rst | 104 ++++++++++++++++++++++++ 2 files changed, 105 insertions(+) create mode 100644 Documentation/sound/cards/marian-m2.rst
diff --git a/Documentation/sound/cards/index.rst b/Documentation/sound/cards/index.rst index e68bbb13c384..e873592d8d00 100644 --- a/Documentation/sound/cards/index.rst +++ b/Documentation/sound/cards/index.rst @@ -19,3 +19,4 @@ Card-Specific Information serial-u16550 img-spdif-in pcmtest + marian-m2 diff --git a/Documentation/sound/cards/marian-m2.rst b/Documentation/sound/cards/marian-m2.rst new file mode 100644 index 000000000000..a968feea79c0 --- /dev/null +++ b/Documentation/sound/cards/marian-m2.rst @@ -0,0 +1,104 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================= +MARIAN Seraph M2 Driver +======================= + +Sep 18, 2023 + +Ivan Orlov ivan.orlov0322@gmail.com + +STATE OF DEVELOPMENT +==================== + +This driver is based on initial driver written by Florian Faber in 2012, which seemed to work fine. +However, the initial code contained multiple issues, which had to be solved before sending the +driver upstream. + +The vendor lost the full documentation, so what we have here was recovered from drafts and found +after experiments with the card. + +What seems to be working fine: +- Playback and capture for all supported rates +- Integrated loopback (with some exceptions, see below) + +MEMORY MODEL +============ + +The hardware requires one huge contiguous DMA space to be allocated. After allocation, the bus address of +this buffer should be written to the hardware register. + +We can split this space into two parts: the first one contains samples for capture, another one contains +play samples: + +CAPTURE_CH_0, CAPTURE_CH_1, ..., CAPTURE_CH_127 | PLAY_CH_0, PLAY_CH_1, ..., PLAY_CH_127 + +The card supports the non-interleaved access mode only, so samples for each channel lay together: + +C0, C0, ..., C0, C1, C1, ..., C1, ..., C127 | C0, C0, ..., C0, C1, C1, ..., C1, ..., C127 + +The count of samples per each channel buffer needs to be set explicitly, so the address of the first +byte of the playback data depends on this value. The playback buffer starts where the capture buffer ends. +It makes the arbitrary period count/buffer size feature impossible to implement, and the driver supports only +2 periods per buffer. + +Controls +======== + +Input 1 Sync + 0 - No signal, 1 - valid MADI signal found, 2 - Synced with MADI signal +Input 2 Sync + 0 - No signal, 1 - valid MADI signal found, 2 - Synced with MADI signal + +Input 1 Channel Mode + 0 - 56 channels, 1 - 64 channels +Input 2 Channel Mode + 0 - 56 channels, 1 - 64 channels + +Input 1 Frame Mode + 0 - 48 kHz, 1 - 96 kHz +Input 2 Frame Mode + 0 - 48 kHz, 1 - 96 kHz + +Input 1 Frequency + Measured frequency on Input 1 +Input 2 Frequency + Measured frequency on Input 2 + +Output 1 Channel Mode + 0 - 56 channels, 1 - 64 channels +Output 2 Channel Mode + 0 - 56 channels, 1 - 64 channels + +Output 1 Frame Mode + 0 - 48 kHz, 1 - 96 kHz +Output 2 Frame Mode + 0 - 48 kHz, 1 - 96 kHz + +Clock Source + Internal/Sync Bus, Input Port 1, Input Port 2 + +Speed mode + VCO clock range (slow/fast) + +DCO Frequency (Hz) + +DCO Frequency (ms) + +DCO Detune + Range: -200...200 + +Loopback + Enable/Disable integrated loopback + + +Loopback +======== + +The card contains integrated loopback. When it is enabled, it sets the hardware’s DAW-in memory pointer +to the hardware’s DAW-out memory. So, what you play is what you record. + +You can enable the integrated loopback using the corresponding control. + +The loopback seems to work well on lower rates (like 28000). However, when the rate goes higher, I observe +multiple mistakes in recorded byte ordering.