Re: [PATCH v8 2/4] fpga manager: add sysfs interface document

atull
2015-01-13T17:27:50Z

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On Tue, 13 Jan 2015, Pavel Machek wrote:

> On Tue 2015-01-13 09:40:18, Pantelis Antoniou wrote:
> > Hi Pavel,
> >
> > > On Jan 13, 2015, at 09:28 , Pavel Machek <pavel@denx.de> wrote:
> > >
> > > Hi!
> > >
> > >>>>>>>>>> +What: /sys/class/fpga_manager/<fpga>/firmware
> > >>>>>>>>>> +Date: October 2014
> > >>>>>>>>>> +KernelVersion: 3.18
> > >>>>>>>>>> +Contact: Alan Tull <atull@opensource.altera.com>
> > >>>>>>>>>> +Description: Name of the FPGA image file to load using firmware
> > >>>>>>>>>> class.
> > >>>>>>>>>
> > >>>>>>>>> This one is ugly: it unneccessarily passes firmware name through the
> > >>>>>>>>> kernel. Just make interface and code simpler by always passing
> > >>>>>>>>> "socfpga-fpga-image" or something like that.
> > > ...
> > >
> > >>> What is cumbersome about symlink? Why is "fake" symlink in sysfs better?
> > >>>
> > >>>> Previous uses of the firmware layer has been to use it to load once after
> > >>>> bootup; this is different since some use cases will want to switch out
> > >>>> the FPGA image. If someone wants there to be only one FPGA image on
> > >>>> the FGPA forever, they will probably not be using this framework; their
> > >>>> FPGA will probably be loaded before Linux boots up.
> > >>>
> > >>> Why? I have just one image on the fpga, and would prefer to load it
> > >>> from Linux.
> > >>
> > >> Pavel: These patches target staging and sysfs interface doesn't need to be stable
> > >> at this time. I would prefer to add these patches to staging for 3.20
> > >> and feel free to send the patch which fix this.
> > >
> > > Interesting way to address patch review. "We'll merge it, and you can
> > > fix it up later".
> > >
> > >> With your code will be exactly clear how you want to use it and we can
> > >> talk about it.
> > >
> > > I'm pretty sure Alan knows what I want at this point, he just does not
> > > want to do it.
> > >
> > > For the record, I want to drop "firmware" file, use fixed firmware
> > > name, and deal with multiple firmwares in userspace (using symlink or
> > > udev magic).
> >
> > That’s completely bogus. Using a fixed firmware file does not respond to
> > real world usage, and there are no words to describe the hacks using
> > symlinks and udev in an embedded product.
>
> > > I believe this is simplest solution, should be adequate, and is
> > > certainly less ugly than implementing fake symlink in
> > > /sys/.../firmware. And I have yet to hear what is wrong with that
> > > suggestion.
> >
> > Everything.
>
> Can you be more specific? Current solution already has a fake symlink,
> implemented badly.
>
> Just remove it, and use real symlink (and then you can optionally
> think of something better...)
>

Hi Pavel,

I still don't get what you are saying. It's not a symlink. I'm not
changing it.

Alan

>
> Pavel
> --
> (english) http://www.livejournal.com/~pavelmachek
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>