linux-kernel - Re: [PATCH v2 05/18] reset: Add reset_controller_of

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Message-ID: <CALszF6AiZ_9Hgz36hyVTSWdtf06QxHnWKjNEjVdU7v7j8m1GiA@mail.gmail.com>
Date:	Thu, 12 Mar 2015 22:08:13 +0100
From:	Maxime Coquelin <mcoquelin.stm32@...il.com>
To:	Rob Herring <robherring2@...il.com>
Cc:	Arnd Bergmann <arnd@...db.de>,
	Maxime Ripard <maxime.ripard@...e-electrons.com>,
	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>,
	Andreas Färber <afaerber@...e.de>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Rob Herring <robh+dt@...nel.org>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	Jonathan Corbet <corbet@....net>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Russell King <linux@....linux.org.uk>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Linus Walleij <linus.walleij@...aro.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
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	Andrew Morton <akpm@...ux-foundation.org>,
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	Joe Perches <joe@...ches.com>, Antti Palosaari <crope@....fi>,
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	Linux-Arch <linux-arch@...r.kernel.org>,
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Subject: Re: [PATCH v2 05/18] reset: Add reset_controller_of_init() function

2015-03-10 22:30 GMT+01:00 Rob Herring <robherring2@...il.com>:
> On Tue, Mar 10, 2015 at 3:19 PM, Arnd Bergmann <arnd@...db.de> wrote:
>> On Tuesday 10 March 2015 16:28:44 Maxime Coquelin wrote:
>>> 2015-03-10 16:00 GMT+01:00 Arnd Bergmann <arnd@...db.de>:
>>> > On Friday 20 February 2015 19:01:04 Maxime Coquelin wrote:
>>> >> Some platforms need to initialize the reset controller before the timers.
>>> >>
>>> >> This patch introduces a reset_controller_of_init() function that can be
>>> >> called before the timers intialization.
>>> >>
>>> >> Signed-off-by: Maxime Coquelin <mcoquelin.stm32@...il.com>
>>> >>
>>> >
>>> > Not sure about this. It seems like the cleanest approach if we get
>>> > a lot of these, but then again it is probably very rare, and I'd
>>> > like to avoid adding such infrastructure if it's just for one
>>> > SoC. Could we add a hack in the machine initialization instead?
>>>
>>> Sun6i also need to initialize the reset controller early. Today, they
>>> hack the machine initialization.
>>> With two SoCs having the same need, what should we do?
>>
>> Good question, I'd like to hear some other opinions on this first.
>
> 2 is still far from the common case.
>
>>> > I think ideally this would be done in the boot loader before we
>>> > even start Linux, but I don't know if that's possible for you.
>>>
>>> From what I understand, the only constraint is to perform it after the
>>> clock is enabled.
>>> So this should be possible to do it in the bootloader, but it means
>>> also adding timers clocks ungating in the bootloader.
>>
>> Ungating the timer clock input seems like a reasonable thing to
>> do for the bootloader, I think a lot of platforms rely on this
>> elsewhere (but enough of them don't, which is why we have the
>> early clk init).
>
> +1
>
> If the bootloader is u-boot, then you need a timer anyway.

Ok, I moved it to the bootloader, and use the reset as optional in the
timer driver.

Thanks,
Maxime
>
> Rob
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