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Tasklist

FS#11108 - USB Audio support

Attached to Project: Rockbox
Opened by amaury pouly (pamaury) - Monday, 15 March 2010, 13:45 GMT+1
Task Type Patches
Category Drivers
Status New
Assigned To amaury pouly (pamaury)
Player Type All players
Severity Low
Priority Normal
Reported Version Daily build (which?)
Due in Version Undecided
Due Date Undecided
Percent Complete 0%
Private No

Details

This flyspray task will hold the development of a potential usb audio driver for rockbox.
It will also serve for the development of the isochronous transfer support support in usb code.
This task depends upon

Comment by amaury pouly (pamaury) - Monday, 15 March 2010, 13:51 GMT+1
This first patch contains my current branch. The code is not clean, not working, well I don't like it :) But if some people are interested, the infrastructure is here but isochronous transfers need more work before this can really work. For this reason, my future work will be to have a clean way to make iso transfers work. The problem is timing: iso transfers happen every 125µs but because of the way completion handlers work, we need a way to queue several transfers. I have ideas about how to do that (that more a kind of static scheduling rather than dynamic queueing).

The first patch contains:
- the usb audio driver
- the usb test driver which is a test driver for iso transfers
The others attachments are the the user land of the usb test interface (linux+libusb).
The test driver is here if you want to do some experiment with iso transfers.
   temp.diff (69.9 KiB) 
 b/firmware/SOURCES                     |    6 
 b/firmware/export/config.h             |    9 
 b/firmware/export/usb.h                |    6 
 b/firmware/export/usb_ch9.h            |    6 
 b/firmware/usb.c                       |   13 
 b/firmware/usbstack/usb_audio.c        |  940 +++++++++++++++++++++++++++++++++
 b/firmware/usbstack/usb_audio.h        |   38 +
 b/firmware/usbstack/usb_audio_def.h    |  233 ++++++++
 b/firmware/usbstack/usb_class_driver.h |   24 
 b/firmware/usbstack/usb_core.c         |  145 ++++-
 b/firmware/usbstack/usb_test.c         |  430 +++++++++++++++
 b/firmware/usbstack/usb_test.h         |   41 +
 b/firmware/usbstack/usb_test_def.h     |   74 ++
 13 files changed, 1946 insertions(+), 19 deletions(-)

   usb_test.c (15.1 KiB)
   usb_test_def.h (2.1 KiB)
Comment by amaury pouly (pamaury) - Thursday, 01 April 2010, 10:34 GMT+1
The code has evolved a lot. It can be found here:
http://github.com/pamaury/rockbox
In the usb-api branch along with a major usb api rewrite (still much work to do to use the new api though)
Comment by T Wolf (towolf) - Friday, 02 September 2011, 19:28 GMT+1
This sounds really cool. Any chance it would eventually work with Sansa Clips?

I suppose that would mean I could use my OpenWrt router with USB as a music player?
Comment by amaury pouly (pamaury) - Tuesday, 06 September 2011, 13:14 GMT+1
Hello,
I'm not currently working on it and the current code has no support for the sansa clips driver. We don't even have a reliable usb driver for clipv2/+...
Yes I guess so, the device would appear as a soundcard. But of course one needs to write the drivers and I don't have time for it now.
Comment by T Wolf (towolf) - Sunday, 11 September 2011, 02:26 GMT+1
I can understand if things are too flaky or time to implement too limited.

Just wanted to give feedback that a feature like this would be super-sweet. Just imagine.

Would ALSA need a driver too besides the appropriate USB handshaking?
Comment by amaury pouly (pamaury) - Sunday, 11 September 2011, 14:51 GMT+1
It only requires the usbaudio driver which is included in all major distros. I tested it with alsa + pulseaudio on top of it and it worked perfectly.

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