linux-kernel - Re: [PATCH v4 2/3] irqchip: GIC: Add support for irq_{get,set}_irqchip

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: <CAL85gmD=12u87vDAc601T=ZOgcS-jDo_=LaC5gRAZUHgp_iTbA@mail.gmail.com>
Date:	Thu, 14 May 2015 13:14:57 -0700
From:	Feng Kan <fkan@....com>
To:	Linus Walleij <linus.walleij@...aro.org>
Cc:	Marc Zyngier <marc.zyngier@....com>,
	Abhijeet Dharmapurikar <adharmap@...eaurora.org>,
	Stephen Boyd <sboyd@...eaurora.org>, Phong Vo <pvo@....com>,
	Tin Huynh <tnhuynh@....com>, Y Vo <yvo@....com>,
	Thomas Gleixner <tglx@...utronix.de>, Toan Le <toanle@....com>,
	Bjorn Andersson <bjorn@...o.se>,
	Jason Cooper <jason@...edaemon.net>,
	Arnd Bergmann <arnd@...db.de>,
	linux-arm-msm <linux-arm-msm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	Alexandre Courbot <gnurou@...il.com>
Subject: Re: [PATCH v4 2/3] irqchip: GIC: Add support for irq_{get,set}_irqchip_state

On Thu, May 14, 2015 at 3:32 AM, Linus Walleij <linus.walleij@...aro.org> wrote:
> On Wed, May 13, 2015 at 5:44 PM, Feng Kan <fkan@....com> wrote:
>
>> We are using the gpio driver with gpio_key for power button. The gpio
>> status can only be retrieved from the GIC register when the gpio is
>> acting as a interrupt.
>
> OK I understand so much. SPISR is a status register of the state
> of the IRQ lines of shared peripherals.
>
> But surely the GPIO block has its own status register, so are
> you saying that this register is unreliable?

When the GPIO is used as interrupt, the gpio block does not report the
status anymore. Which leaves us stuck with SPISR.
>
> I can think of a few reasons, like transient IRQs etc but
> what is actually causing this?

I won't say the obvious.
>
> Techically the GIC would normally be higher up the food
> chain, i.e. one IRQ on the GIC is cascaded to sub-IRQs on
> the GPIO chip by virtue of its own struct irq_chip and
> irqdomain. The exception is typically only systems where
> the GPIO block is fused with the IRQ controller so that each
> GPIO line has its own unique IRQ line on the primary,
> top-level interrupt controller.
>
> Which GPIO driver is this? Is it upstream?
Yes, it is upstream. It is the xgene slimpro gpio driver. I am starting to
think that we ought to switch to use some gpio poll driver rather than
using gpio-key.
>
> Yours,
> Linus Walleij
--
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/