oxfw: Split stream functionality to a new file and add a header file

To make it easy to work in followed commit.

And this commit remove 'fw_unit_get()/fw_unit_put()' because these
are called by helper functions in 'snd-firewire-lib'.
oxfw: Split PCM functionality to a new file

To make it easy to work in followed commit.
oxfw: Split control functionality to a new file

To make it easy to work in followed commit.
oxfw: Change the way to name card

'struct snd_card' has 4 members for name. They're 'driver', 'shortname',
'longname' and 'mixername'. The 'driver' is used to detect card
Configuration file but the others are not used for important
functionality. So it's OK to name them with the information from config
ROM.

This commit adds 'name_card()' function and change the way to name card.
The 'driver' is still given by 'struct device_info'. The 'shortname' and
'mixername' is given by 'model' and the 'longname' is given by 'vendor'
and 'model'.
oxfw: Change the way to make PCM rules/constraints

For PCM rules/constrains, drivers need to know stream formation at each
supported sampling rates in advance. This commit adds
'struct snd_oxfw_stream_formation' to save formation information.

According to datasheet of OXFW970/971, they support 32.0kHz to 196.0kHz.
So this commit adds 'rx_stream_formations' member to 'struct snd_oxfw'. It's
an array with 7 elements. Each element corresponds to each sampling rate.

With these data structure, this commit changes the way to make PCM
rules/constraints.

I don't know whether Griffin/LaCie devices supports SINGLE/LIST subfunction
'AV/C Stream Format Information' command. So this commit adds codes to
generate formations for them.
oxfw: Add proc interface for debugging purpose

The previous commit adds stream formation. This commit adds proc interface
to get information about:
 - stream formation
 - current sampling rate
oxfw: Change the way to start stream

In past commit, driver can keep formations for each sampling rate. So its
stream functionality can set its formation when given sampling rate.

But PCM functionality still set it. This commit move some codes to set
stream formation from PCM functionality to stream functionality.
oxfw: Add some AV/C commands to get stream formation and supported sample rate

OXFW970/971 may supports AV/C Stream Format Information Specification 1.1
Working Draft (Apr 2005, 1394TA). So this driver uses 'EXTENDED STREAM FORMAT
INFORMATION' command.

This command has two subfunctions, 'SINGLE' and 'LIST'. Drivers can use
'SINGLE' subfunction to know current formation of AMDTP stream, Drivers can
use 'LIST' subfunction to know an available formation of AMDTP stream in a
certain sampling rate. Followed commit adds parser for returned information.

This commit adds 'inquiry' version of 'PLUG SIGNAL FORMAT' command. When
device doesn't support 'LIST' subfunction of 'AV/C Stream Format Information
command, this driver uses 'inquiry' command to get supported sampling rates.
oxfw: Add support for Behringer/Mackie devices

FFADO project have already identified that some devices produced by
Behringer/Mackie are based on OXFW970/971.

Behringer/Mackie devices support capture/playback of PCM-samples and some
of them supports capture/playback of MIDI-messages. Followed commits will
add these functionalities.

They support 'AV/C Stream Format Information' command. But some of them
don't implement 'LIST' subfunction. So this commit uses an assumption
that 'if they don't implement it, they don't change formation of stream
for each sampling rate'.

With this assumption, this driver generate formations for the devices by:
 1.getting current formation by SINGLE subfunction
 2.getting supported sampling rates
 3.applying current formation for all of supported sampling rates
oxfw: Add support AMDTP in-stream and PCM capture

Previous commit adds support for some devices which can capture PCM samples.
These devices transmit AMDTP stream in non-blocking mode. The stream from
these devices has a quirk for 'presentation timestamp'.

The sequence of 'presentation timestamp' is invalid even if header of packet
shows 'CIP header with SYT field'. So this driver can't reuse the timestamp
for out stream.

In this reason, this driver handles both streams separately.
oxfw: Add support for capture/playback MIDI messages

I assume that 'if the device has MIDI comformant data channels in its
stream formation, the device has one MIDI port'. With this assumption,
this driver create MIDI devices.

When no streams have already started, MIDI functionality starts stream
with current sampling rate.

When MIDI functionality has already starts some streams and PCM
functionality is going to start streams at different sampling rate,
this driver stops streams once and changes sampling rate, then restarts
streams.
oxfw: Add hwdep interface

This interface is designed for mixer/control application. To use hwdep
interface, the application can get information about firewire node, can
lock/unlock kernel streaming and can get notification at starting/stopping
kernel streaming.