linux-kernel - Re: [PATCH v3 5/5] clk: export tree topology and clk data via sysfs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20111123165903.GF31337@atomide.com>
Date:	Wed, 23 Nov 2011 08:59:04 -0800
From:	Tony Lindgren <tony@...mide.com>
To:	Greg KH <greg@...ah.com>
Cc:	Mike Turquette <mturquette@...aro.org>,
	linaro-dev@...ts.linaro.org, eric.miao@...aro.org,
	grant.likely@...retlab.ca, jeremy.kerr@...onical.com,
	Mike Turquette <mturquette@...com>, linux@....linux.org.uk,
	sboyd@...cinc.com, magnus.damm@...il.com, dsaxena@...aro.org,
	linux-arm-kernel@...ts.infradead.org, arnd.bergmann@...aro.org,
	patches@...aro.org, tglx@...utronix.de, linux-omap@...r.kernel.org,
	richard.zhao@...aro.org, shawn.guo@...escale.com, paul@...an.com,
	linus.walleij@...ricsson.com, broonie@...nsource.wolfsonmicro.com,
	linux-kernel@...r.kernel.org, amit.kucheria@...aro.org,
	skannan@...cinc.com
Subject: Re: [PATCH v3 5/5] clk: export tree topology and clk data via sysfs

Hi Mike,

* Greg KH <greg@...ah.com> [111122 10:51]:
> On Tue, Nov 22, 2011 at 09:57:41AM -0800, Mike Turquette wrote:
> > > Ah, comments like this warm my heart.
> > >
> > > Come on, no abusing the kobject code please, if have problems with how
> > > the kernel core works, and it doesn't do things you want it to, then why
> > > not change it to work properly for you, or at the least, ASK ME!!!
> > 
> > Ok, I'm asking you now.  There are two ways to solve this problem:
> > 
> > 1) have kobject core create the lists linking the objects but defer
> > allocations and any interactions with sysfs until later in the boot
> > sequence, OR

Please just make it all a loadable module using regular devices. That
makes the development a lot easier and as a side effect also guarantees
we're using standard interfaces.

Sure most platforms using it want it compiled in at least for now,
but in the long run it should be possible to load it when we get to
initramfs. For the early usage of clocks..

> > 2) my code can create a list of clks (the same way that clkdev does)
> > and defer kobject/sysfs stuff until later, which walks the list made
> > during early-boot

..let's plan on getting rid of the early usage of clocks instead so
you don't have the issue of deferring stuff.

> > #1 is most closely aligned with the code I have here, #2 presents
> > challenges that I haven't really though through.  I know that OMAP
> > uses the clk framework VERY early in it's boot sequence, but as long
> > as the per-clk data is properly initialized then it should be OK.
> > 
> > What do you think?

We initialize clocksource/clockevent clocks early, but we can do that
without clock fwk initially, then let a clockevent driver take over
later on. That should solve your issues #1 and #2.

> #3 - use debugfs and don't try to create a sysfs interface for the clock
> structures :)

Sounds like the debugfs is the way to go :)

Tony
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/