Pace I/O timing to match the audio interface.
Enable interrupts while copying buffers.

pad(4): Omit unused sc_blksize.

pad(4): Sort includes. Add missing includes to padvar.h.

pad(4): Fix some locking.

- No need for sc_cond_lock.
- Issue cv_broadcast under the correct lock.
- Use callout_halt, not haphazard callout_stop.
- IPL_SOFTCLOCK for a mutex taken from a callout.

branches: 1.13.14;
Style fixes. No functional changes intended.
- Rename some functions for consistency.
- Rearrange some functions for readability.
- Unify to struct pad_softc.

Merge isaki-audio2 branch, the overhaul of audio subsystem.
- Interrupt-oriented system rather than thread-oriented.
- Improve stability, quality and performance.
- Split playback and record cleanly. Improve halfduplex support.
- Many bugs are fixed including deadlocks, resource leaks, abuses, etc.
- Simplify audio filter mechanism. The encoding/channels/frequency
conversions are completely handled in the upper layer. So the hard-
ware driver only converts its hardware encoding (if necessary).
- audio_hw_if changes:
- Obsoletes query_encoding and add query_format instead.
- Obsoletes set_params and add set_format instead.
- Remove drain, setfd, mappage.
- The call sequences are changed.
- ioctl AUDIO_GETFD/SETFD, AUDIO_GETCHAN/SETCHAN are obsoleted.
- ioctl AUDIO_{QUERY,GET,SET}FORMAT are introduced.
- cleanup config attributes: au*conv and mulaw.
- All hardware drivers should follow it (I've done as much as possible).

Some file paths are changed:
- dev/audio.c -> dev/audio/audio.c (rewritten)
- dev/audiovar.h -> dev/audio/audiovar.h
- dev/audio_dai.h -> dev/audio/audio_dai.h
- dev/audio_if.h -> dev/audio/audio_if.h
- dev/audiobell.c -> dev/audio/audiobell.c
- dev/audiobellvar.h -> dev/audio/audiobellvar.h
- dev/mulaw.[ch] -> dev/audio/mulaw.[ch] + dev/audio/alaw.c

branches: 1.11.6; 1.11.10;
Pad is now clones its device, attaching upon open and detaching upon close.
This means that only one pad device is required in /dev.

The code contains a compile time limit of 128 units.

Ok christos@.

sc_audiodev should be defined as a device_t as this is what audio_attach_mi
returns.

pad blocksize 1024 -> 8192. Helps when sleeping in rate limiter.

branches: 1.8.2;
Rework of previous.
Math for BYTESTOSLEEP and TIMENEXTREAD is now correct.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

branches: 1.6.2; 1.6.4;
Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.8; 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

pad(4): Omit unused sc_blksize.

pad(4): Sort includes. Add missing includes to padvar.h.

pad(4): Fix some locking.

- No need for sc_cond_lock.
- Issue cv_broadcast under the correct lock.
- Use callout_halt, not haphazard callout_stop.
- IPL_SOFTCLOCK for a mutex taken from a callout.

Style fixes. No functional changes intended.
- Rename some functions for consistency.
- Rearrange some functions for readability.
- Unify to struct pad_softc.

Merge isaki-audio2 branch, the overhaul of audio subsystem.
- Interrupt-oriented system rather than thread-oriented.
- Improve stability, quality and performance.
- Split playback and record cleanly. Improve halfduplex support.
- Many bugs are fixed including deadlocks, resource leaks, abuses, etc.
- Simplify audio filter mechanism. The encoding/channels/frequency
conversions are completely handled in the upper layer. So the hard-
ware driver only converts its hardware encoding (if necessary).
- audio_hw_if changes:
- Obsoletes query_encoding and add query_format instead.
- Obsoletes set_params and add set_format instead.
- Remove drain, setfd, mappage.
- The call sequences are changed.
- ioctl AUDIO_GETFD/SETFD, AUDIO_GETCHAN/SETCHAN are obsoleted.
- ioctl AUDIO_{QUERY,GET,SET}FORMAT are introduced.
- cleanup config attributes: au*conv and mulaw.
- All hardware drivers should follow it (I've done as much as possible).

Some file paths are changed:
- dev/audio.c -> dev/audio/audio.c (rewritten)
- dev/audiovar.h -> dev/audio/audiovar.h
- dev/audio_dai.h -> dev/audio/audio_dai.h
- dev/audio_if.h -> dev/audio/audio_if.h
- dev/audiobell.c -> dev/audio/audiobell.c
- dev/audiobellvar.h -> dev/audio/audiobellvar.h
- dev/mulaw.[ch] -> dev/audio/mulaw.[ch] + dev/audio/alaw.c

branches: 1.11.6; 1.11.10;
Pad is now clones its device, attaching upon open and detaching upon close.
This means that only one pad device is required in /dev.

The code contains a compile time limit of 128 units.

Ok christos@.

sc_audiodev should be defined as a device_t as this is what audio_attach_mi
returns.

pad blocksize 1024 -> 8192. Helps when sleeping in rate limiter.

branches: 1.8.2;
Rework of previous.
Math for BYTESTOSLEEP and TIMENEXTREAD is now correct.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

branches: 1.6.2; 1.6.4;
Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.8; 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

pad(4): Sort includes. Add missing includes to padvar.h.

pad(4): Fix some locking.

- No need for sc_cond_lock.
- Issue cv_broadcast under the correct lock.
- Use callout_halt, not haphazard callout_stop.
- IPL_SOFTCLOCK for a mutex taken from a callout.

Style fixes. No functional changes intended.
- Rename some functions for consistency.
- Rearrange some functions for readability.
- Unify to struct pad_softc.

Merge isaki-audio2 branch, the overhaul of audio subsystem.
- Interrupt-oriented system rather than thread-oriented.
- Improve stability, quality and performance.
- Split playback and record cleanly. Improve halfduplex support.
- Many bugs are fixed including deadlocks, resource leaks, abuses, etc.
- Simplify audio filter mechanism. The encoding/channels/frequency
conversions are completely handled in the upper layer. So the hard-
ware driver only converts its hardware encoding (if necessary).
- audio_hw_if changes:
- Obsoletes query_encoding and add query_format instead.
- Obsoletes set_params and add set_format instead.
- Remove drain, setfd, mappage.
- The call sequences are changed.
- ioctl AUDIO_GETFD/SETFD, AUDIO_GETCHAN/SETCHAN are obsoleted.
- ioctl AUDIO_{QUERY,GET,SET}FORMAT are introduced.
- cleanup config attributes: au*conv and mulaw.
- All hardware drivers should follow it (I've done as much as possible).

Some file paths are changed:
- dev/audio.c -> dev/audio/audio.c (rewritten)
- dev/audiovar.h -> dev/audio/audiovar.h
- dev/audio_dai.h -> dev/audio/audio_dai.h
- dev/audio_if.h -> dev/audio/audio_if.h
- dev/audiobell.c -> dev/audio/audiobell.c
- dev/audiobellvar.h -> dev/audio/audiobellvar.h
- dev/mulaw.[ch] -> dev/audio/mulaw.[ch] + dev/audio/alaw.c

branches: 1.11.6; 1.11.10;
Pad is now clones its device, attaching upon open and detaching upon close.
This means that only one pad device is required in /dev.

The code contains a compile time limit of 128 units.

Ok christos@.

sc_audiodev should be defined as a device_t as this is what audio_attach_mi
returns.

pad blocksize 1024 -> 8192. Helps when sleeping in rate limiter.

branches: 1.8.2;
Rework of previous.
Math for BYTESTOSLEEP and TIMENEXTREAD is now correct.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

branches: 1.6.2; 1.6.4;
Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.8; 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

Style fixes. No functional changes intended.
- Rename some functions for consistency.
- Rearrange some functions for readability.
- Unify to struct pad_softc.

Merge isaki-audio2 branch, the overhaul of audio subsystem.
- Interrupt-oriented system rather than thread-oriented.
- Improve stability, quality and performance.
- Split playback and record cleanly. Improve halfduplex support.
- Many bugs are fixed including deadlocks, resource leaks, abuses, etc.
- Simplify audio filter mechanism. The encoding/channels/frequency
conversions are completely handled in the upper layer. So the hard-
ware driver only converts its hardware encoding (if necessary).
- audio_hw_if changes:
- Obsoletes query_encoding and add query_format instead.
- Obsoletes set_params and add set_format instead.
- Remove drain, setfd, mappage.
- The call sequences are changed.
- ioctl AUDIO_GETFD/SETFD, AUDIO_GETCHAN/SETCHAN are obsoleted.
- ioctl AUDIO_{QUERY,GET,SET}FORMAT are introduced.
- cleanup config attributes: au*conv and mulaw.
- All hardware drivers should follow it (I've done as much as possible).

Some file paths are changed:
- dev/audio.c -> dev/audio/audio.c (rewritten)
- dev/audiovar.h -> dev/audio/audiovar.h
- dev/audio_dai.h -> dev/audio/audio_dai.h
- dev/audio_if.h -> dev/audio/audio_if.h
- dev/audiobell.c -> dev/audio/audiobell.c
- dev/audiobellvar.h -> dev/audio/audiobellvar.h
- dev/mulaw.[ch] -> dev/audio/mulaw.[ch] + dev/audio/alaw.c

branches: 1.11.6; 1.11.10;
Pad is now clones its device, attaching upon open and detaching upon close.
This means that only one pad device is required in /dev.

The code contains a compile time limit of 128 units.

Ok christos@.

sc_audiodev should be defined as a device_t as this is what audio_attach_mi
returns.

pad blocksize 1024 -> 8192. Helps when sleeping in rate limiter.

branches: 1.8.2;
Rework of previous.
Math for BYTESTOSLEEP and TIMENEXTREAD is now correct.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

branches: 1.6.2; 1.6.4;
Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.8; 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

Merge isaki-audio2 branch, the overhaul of audio subsystem.
- Interrupt-oriented system rather than thread-oriented.
- Improve stability, quality and performance.
- Split playback and record cleanly. Improve halfduplex support.
- Many bugs are fixed including deadlocks, resource leaks, abuses, etc.
- Simplify audio filter mechanism. The encoding/channels/frequency
conversions are completely handled in the upper layer. So the hard-
ware driver only converts its hardware encoding (if necessary).
- audio_hw_if changes:
- Obsoletes query_encoding and add query_format instead.
- Obsoletes set_params and add set_format instead.
- Remove drain, setfd, mappage.
- The call sequences are changed.
- ioctl AUDIO_GETFD/SETFD, AUDIO_GETCHAN/SETCHAN are obsoleted.
- ioctl AUDIO_{QUERY,GET,SET}FORMAT are introduced.
- cleanup config attributes: au*conv and mulaw.
- All hardware drivers should follow it (I've done as much as possible).

Some file paths are changed:
- dev/audio.c -> dev/audio/audio.c (rewritten)
- dev/audiovar.h -> dev/audio/audiovar.h
- dev/audio_dai.h -> dev/audio/audio_dai.h
- dev/audio_if.h -> dev/audio/audio_if.h
- dev/audiobell.c -> dev/audio/audiobell.c
- dev/audiobellvar.h -> dev/audio/audiobellvar.h
- dev/mulaw.[ch] -> dev/audio/mulaw.[ch] + dev/audio/alaw.c

branches: 1.11.10;
Pad is now clones its device, attaching upon open and detaching upon close.
This means that only one pad device is required in /dev.

The code contains a compile time limit of 128 units.

Ok christos@.

sc_audiodev should be defined as a device_t as this is what audio_attach_mi
returns.

pad blocksize 1024 -> 8192. Helps when sleeping in rate limiter.

branches: 1.8.2;
Rework of previous.
Math for BYTESTOSLEEP and TIMENEXTREAD is now correct.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

branches: 1.6.2; 1.6.4;
Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.8; 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

Pad is now clones its device, attaching upon open and detaching upon close.
This means that only one pad device is required in /dev.

The code contains a compile time limit of 128 units.

Ok christos@.

sc_audiodev should be defined as a device_t as this is what audio_attach_mi
returns.

pad blocksize 1024 -> 8192. Helps when sleeping in rate limiter.

branches: 1.8.2;
Rework of previous.
Math for BYTESTOSLEEP and TIMENEXTREAD is now correct.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

branches: 1.6.2; 1.6.4;
Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

sc_audiodev should be defined as a device_t as this is what audio_attach_mi
returns.

pad blocksize 1024 -> 8192. Helps when sleeping in rate limiter.

branches: 1.8.2;
Rework of previous.
Math for BYTESTOSLEEP and TIMENEXTREAD is now correct.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

branches: 1.6.2; 1.6.4;
Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

pad blocksize 1024 -> 8192. Helps when sleeping in rate limiter.

Rework of previous.
Math for BYTESTOSLEEP and TIMENEXTREAD is now correct.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

branches: 1.6.2; 1.6.4;
Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

Rework of previous.
Math for BYTESTOSLEEP and TIMENEXTREAD is now correct.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

branches: 1.6.2; 1.6.4;
Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

Update pad due to changes in audio. sc_bytes_count and BYTESTOSLEEP are
no longer required.

Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.

Allow reads from pad(4) less or greater than PAD_BLKSIZE.

Ensure that audio data is ready before reading.
Addresses PR 39204.

OK jmcneil@.

branches: 1.5.2;
Add common audio converters for software volume control. Only supports
slinear16_le and slinear16_be for now.

Convert pad(4) to use the new converters.

branches: 1.4.24;
Merge jmcneill-audiomp3 branch, which is derived from ad-audiomp2. From
the original ad-audiomp branch notes:

Add MP locking to the audio drivers.

Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.

The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.

Welcome to 5.99.57.

branches: 1.3.6; 1.3.28; 1.3.30;
fix device is not split warning

branches: 1.2.4;
Use 2-clause license.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.18; 1.1.24; 1.1.26; 1.1.28; 1.1.30;
Implement volume controls for pseudo audio device.