linux-kernel - Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document

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]

Date:	Fri, 18 Mar 2016 14:47:28 +0200
From:	Grygorii Strashko <grygorii.strashko@...com>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Jon Hunter <jonathanh@...dia.com>
CC:	Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>,
	Marc Zyngier <marc.zyngier@....com>,
	Benoît Cousson <bcousson@...libre.com>,
	Tony Lindgren <tony@...mide.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Stephen Warren <swarren@...dotorg.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Kevin Hilman <khilman@...nel.org>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Linus Walleij <linus.walleij@...aro.org>,
	<linux-tegra@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from
 binding document

On 03/18/2016 02:05 PM, Geert Uytterhoeven wrote:
> Hi Jon,
> 
> On Fri, Mar 18, 2016 at 11:56 AM, Jon Hunter <jonathanh@...dia.com> wrote:
>> On 18/03/16 10:52, Geert Uytterhoeven wrote:
>>> On Fri, Mar 18, 2016 at 11:13 AM, Jon Hunter <jonathanh@...dia.com> wrote:
>>>> On 18/03/16 09:13, Geert Uytterhoeven wrote:
>>>>> On Thu, Mar 17, 2016 at 3:19 PM, Jon Hunter <jonathanh@...dia.com> wrote:
>>>>>> Commit afbbd2338176 ("irqchip/gic: Document optional Clock and Power
>>>>>> Domain properties") documented optional clock and power-dmoain properties
>>>>>> for the ARM GIC. Currently, there are no users of these and for the
>>>>>> Tegra210 Audio GIC (based upon the GIC-400) there are two clocks, a
>>>>>> functional clock and interface clock, that need to be enabled.
>>>>>
>>>>> The reason that there are no users for this is twofold:
>>>>>    1. The GIC driver doesn't have Runtime PM support yet,
>>>>>    2. There was no clean way to prevent the GIC's clock from being disabled.
>>>>> Due to this, adding the clocks to the DTSes would mean that they will be
>>>>> disabled during boot up as unused clocks, leading to a system lock-up.
>>>>>
>>>>> I had hoped your series would fix part 1. I gave it a try on r8a7791/koelsch,
>>>>> but unfortunately it seems the platform driver only supports non-root
>>>>> controllers, while the r8a7791 GIC is the primary one...
>>>>
>>>> Can you try making the following change ...
>>>
>>> Thanks! I gave it a try, but no difference.
>>
>> I assume you added the appropriate compatible flag? Any more details you
> 
> Doh... bad assumption... Silly me.
> 
>> can share about why it is not working? Is it not registered early enough?
> 
> With
> 
> +       { .compatible = "arm,gic-400", },
> 
> the kernel no longer crashes due to accessing the GIC registers while the
> GIC module clock is disabled.
> 
> However, the system doesn't boot completely, and time outs on SPI transfers
> make me believe interrupts are not working.
> Both with and without "the following change".
> 

Is my assumption correct that you are trying to enable RPM for primary GIC controller?


If yes it may help to take a look on clocksource drivers which use early_platform_device/driver
sh_cmt.c sh_mtu2.c sh_tmu.c

The primary interrupt controller is initialized very early init_IRQ->irqchip_init->of_irq_init()
(IRQCHIP_DECLARE) and, at least as i can see from st_xxx code, the same case is valid for 
clocksource devices and it was solved using early_platform_device/drive staff.


-- 
regards,
-grygorii