RE: [lwip-users] LwIP port on Blackfin, some questions and 1.3.0

[Stéphane Lesage]

> Hello, Stéphane
> 
> Analog Devices has normally been using lwIP 1.2.0 as of 
> VisualDSP 5.0; I'm pretty sure about it since in our product 
> we've been using some features that didn't exist in the old 
> (0.6.something) release. If you think you're not linking with 
> the correct lwIP version, please double check the .lib's name 
> and the include paths of your VisualDSP project.

You're right, VDSP 5.0 ships with LwIP (almost) 1.2.0.
Actually 4.5 June update already had it,
that's why I could not find any difference and thought it was an old
version.
(they probably updated it with February update)

> To upgrade the lwIP library used by Analog Devices, you may try the
> following:
>     1. Do a checkout of version 1.2.0
>     2. Copy and paste on to that checkout the lwIP source 
> code from VisualDSP 5's "src" folder.
>     3. Your versionning tool (I use Tortoise in Windows) 
> should then show you that there are some differences. Now do 
> an "update" on your checkout.

They are a lot of A.D. specific modifications in the source code,
and it's not easy to manually integrate them in a new LwIP release.

Your method let the CVS tool do it automatically.
Until recently I didn't know it could
add new release modifications while keeping local modifications.
I will test this with WinCVS.
Thanks for the advice.

LwIP is well written and separates the architecture layer.
I don't like that A.D modified the portable part...
I'm still thinking to do a clean port someday.

> As for your real-time audio project, how does it work? Are 
> you using VDK or the lwIP core with your semaphore code? If 
> you're having problems with dropped audio frames, are you 
> sure you're using DMA the correct way? If you're having lags, 
> are you sure you have the right buffer sizes?

Actually I have no problem on my VoIP project,
because it's frame-based and of course using double-buffering DMA.

My concern is another project using real-time (sample-based) audio
processing,
with 48000 interrupts per second, processing 8 in / 8 out 32 bits channels.
We want to add IP interfaces to this kind of devices for configuration and
control.
I'm afraid VDK and A.D ethernet driver have too much "critical regions" with
interrupts disabled.


-- 
Stéphane Lesage