Re: [rfc] exposing MMR's of on-chip peripherals for debuggingpurposes

From: Daniel Barkalow
Date: Mon Jan 28 2008 - 19:09:01 EST


On Mon, 28 Jan 2008, Mike Frysinger wrote:

> On Jan 28, 2008 8:04 AM, richard kennedy <richard@xxxxxxxxxxxxxxx> wrote:
> > Mike Frysinger wrote:
> > > On Jan 28, 2008 5:40 AM, Bryan Wu <bryan.wu@xxxxxxxxxx> wrote:
> > >> On Mon, 2008-01-28 at 05:16 -0500, Mike Frysinger wrote:
> > >>> the trouble is that this file currently weighs in at ~1.8 megs. this
> > >>> is because it contains all the information for all Blackfin processors
> > >>> we support (which currently, is about ~23 variants). it's only going
> > >>> to get bigger as we support more. Bryan cringes at the thought of
> > >>> submitting it to LKML :). so i'm fishing around for alternatives ...
> > >>> the code was originally developed against 2.6.21, so UIO was not a
> > >>> possibility. i'm still not sure if it is ... i'd have to research it
> > >>> a bit more and play with things.
> > >> The main reason I am not willing to submit this to mainline is the file
> > >> size. It's almost the biggest file in the kernel source. And it will be
> > >> bigger and bigger when more and more new Blackfin processors supported
> > >> by Linux kernel.
> > >
> > > a quick check of current git shows it is significantly larger than any other ;)
> > >
> > >> My suggestion is:
> > >> Or more deeper thought:
> > >> - we don't need all the MMR setup at the same time for debugging. for example, maybe for some developer, he/she only needs one driver MMR for debugging such as watchdog/usb/spi/i2c ....
> > >
> > > splitting things up doesnt really address the original issue: there's
> > > a lot of info here to be kept in the kernel
> > >
> > >> - How about split the debug MMR table to each drivers or processors?
> > >> - watchdog driver implements a debug FS interface for debugging watchdog MMR and other drivers implement their own things.
> > >
> > > this had been mentioned before as a possibility but shot down. you do
> > > not want to tie the creation of these debug files to anything as the
> > > prevents independent development of any other drivers/application that
> > > use the same peripheral.
> >
> > there is a lot of duplication in your file, but you could slim it down a
> > bit if thats the only objection.
>
> i imagine there's a ton of duplication ... the file is auto-generated
> from XML files, so i could take a look at the autogeneration producing
> unified code.

Could you submit the XML files and the autogeneration code? The C file
isn't really source. Not only is it big, it'll probably change around a
whole lot when you make small changes to your process, be hard to review,
etc.

-Daniel
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