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STM32 USB support
- From: Chris Holgate <chris at zynaptic dot com>
- To: Simon Kallweit <simon dot kallweit at intefo dot ch>, ecos-devel at sourceware dot org
- Date: Tue, 19 May 2009 12:47:00 +0100
- Subject: STM32 USB support
- References: <4A11CAAA.firstname.lastname@example.org> <4A11D861.email@example.com> <4A11E5DF.firstname.lastname@example.org>
Simon Kallweit wrote:
> Chris Holgate schrieb:
>> It's stable in my application using my own Linux kernel driver (several
>> million bulk and interrupt transactions and counting!).
> That sound's pretty stable to me :)
OK - I've now done a bit of tidying up which I hope won't have broken
it! The latest version of the package is here:
There are a couple of minor TODO's which I need to revisit before a
proper release, but nothing significant.
>> However, I've not had much luck getting it working with the standard
>> eCos test framework - although I now suspect thats a Linux usbfs issue
>> rather than my driver. I also need to sort out some proper
> Well, I could do some testing too and see where I get.
That would be very helpful, although I think that the standard host-side
tests have only ever been run on a pretty old version of Linux. I'd
have more confidence in testing against some standard drivers like a
virtual serial port or a 'memory stick' device.
>> There is a significant difference from the other USB drivers which I
>> should probably flag up (and document). The endpoint configuration is
>> generated dynamically from the USB descriptors. This gives a lot of
>> flexibility and potentially allows support for multiple configurations
>> (untested!). However, the downside is that I had to leave out devtab
>> support since the devtab entries need to be set statically.
> Don't you think it's possible to have both options? I haven't looked at
> the USB subsystem or any drivers, but I think a public driver should
> behave as the subsystem intends. Maybe the subsystem could be extended
> for more dynamic usage though.
The official docs say "To support this the device driver can provide a
devtab entry for each endpoint". I took that to mean that devtab
support was optional - and the dynamic endpoint configuration is a much
more useful feature IMHO.
Previously supported hardware has had fixed endpoint configurations
which makes the static devtab entries easy to implement. However, with
dynamic endpoint configuration, the low-level driver doesn't know
a-priori what endpoints to generate devtab entries for - and nor should it!
Copied to the list, since I'm sure there are other people who would like