Re: [PATCH 1/1] mtd/intel-spi: Support cmdline-based partition

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Mika,

Mika Westerberg <mika.westerberg@linux.intel.com> wrote on Mon, 30 Mar
2020 09:08:59 +0300:

> No objections from my side :)
> 
> On Fri, Mar 27, 2020 at 04:53:28PM -0700, ron minnich wrote:
> > OK, I've done a quick prototype of using () as one way to specify the
> > ID. The mtparts can look like this (tested)
> > 
> > mtdparts=(0000:00:1f.5)25165824(BIOS),-(squashfs)

Would it be hard to support an extra ':' after the MTD device name?
This way would would allow anything inside the optional '(' ')' but
would keep the trailing ':'.

toTay:
	mtdparts=name:part1,part2

So:
	mtdparts=(0000:00:1f.5):25165824(BIOS),-(squashfs)

?

> > 
> > The text in () can be pretty arbitrary; only ) is disallowed.
> > It's about 10 more lines of code in cmdlinepart.c and that's it.
> > Further, the existing syntax is still supported:
> > mtdparts=id:parts
> > 
> > what do you think?
> > 
> > thanks
> > 
> > ron
> > 
> > On Fri, Mar 27, 2020 at 10:39 AM ron minnich <rminnich@gmail.com> wrote:  
> > >
> > > yeah, :: is not so bad, but you've got a lot of corner cases as you check for ::
> > > mtdparts=0:
> > > for one example.
> > >
> > > Covering all the ways things can go wrong gets messy. You can pretty
> > > much guarantee all those corner cases will get exercised ...
> > >
> > > And people are going to mess this up and end up with hard to debug errors:
> > > mtdparts=0000::0:1f.3:parts
> > >
> > > That could be a hard error to spot.
> > >
> > > I still wonder if we should not just define some character as
> > > available in addition to :. I realize | was pretty awful, but ... is
> > > there some other character we might use? I kind of like the simplicity
> > > of the current scheme; there really would be no issue had it been
> > > almost anything but a : :-)
> > >
> > > But if the sense is that :: is the way to go, I can give it a shot.
> > >
> > > ron
> > >
> > > On Fri, Mar 27, 2020 at 10:16 AM Mika Westerberg
> > > <mika.westerberg@linux.intel.com> wrote:  
> > > >
> > > > On Fri, Mar 27, 2020 at 10:05:52AM -0700, ron minnich wrote:  
> > > > > I did try the \ thing but found it a bit tricky to work with, with
> > > > > lots of potential for simple errors.
> > > > >
> > > > > It would require cmdlines like this
> > > > > mtdparts=0000\:00\:0.1f:etcetc
> > > > >
> > > > > A lot of these mtdparts definitions are produced by scripts and
> > > > > Makefiles and there are many, many places where \\ have a way of
> > > > > vanishing.  
> > > >
> > > > Right. One option would be to use the printf() style escaping and make
> > > > :: to be literal : in the same way %% is literal %.  

Thanks,
Miquèl

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