linux-kernel - Re: [PATCH] irqchip/gicv3: remove disabling redistributor and group1 non-secure interrupts

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Message-ID: <29104bbe-d5ea-3f48-d75b-f0863b64d28d@arm.com>
Date:	Wed, 17 Aug 2016 13:39:10 +0100
From:	Sudeep Holla <sudeep.holla@....com>
To:	Christopher Covington <cov@...eaurora.org>,
	linux-kernel@...r.kernel.org
Cc:	Sudeep Holla <sudeep.holla@....com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>,
	Marc Zyngier <marc.zyngier@....com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
	Prashanth Prakash <pprakash@...eaurora.org>
Subject: Re: [PATCH] irqchip/gicv3: remove disabling redistributor and group1
 non-secure interrupts

Hi Christopher,

On 16/08/16 20:21, Christopher Covington wrote:
> Thanks Sudeep!
>
> On 08/16/2016 06:19 AM, Sudeep Holla wrote:
>> As per the GICv3 specification, to power down a processor using GICv3
>> and allow automatic power-on if an interrupt must be sent to a processor,
>> software must set Enable to zero for all interrupt groups(by writing
>> to GICC_CTLR or ICC_IGRPEN{0,1}_EL1/3 as appropriate.
>>
>> When commit 3708d52fc6bb ("irqchip: gic-v3: Implement CPU PM notifier")
>> was introduced there were no firmware implementations(in particular PSCI)
>> handling this.
>>
>> Linux kernel may not be aware of the CPU power state details and might
>> fail to identify the power states that require quiescing the CPU
>> interface. Even if it can be aware of those details, it can't determine
>> which CPU power state have been triggered at the platform level and how
>> the power control is implemented.
>>
>> This patch make disabling redistributor and group1 non-secure interrupts
>> in the power down path and re-enabling of redistributor in the power-up
>> path conditional. It will be handled in the kernel if and only if the
>> non-secure accesses are permitted to access and modify control registers.
>> It is left to the platform implementation otherwise.
>>
>> Cc: Marc Zyngier <marc.zyngier@....com>
>> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
>> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
>> ---
>>  drivers/irqchip/irq-gic-v3.c | 11 +++++++++--
>>  1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> Hi Christopher,
>>
>> Can you check if ACPI processor idle works with this patch on QDF2432 ?
>
> This fixes the boot hang, and I see the usage and time files in cpuidle
> sysfs increasing on an idle system.
>
> Tested-by: Christopher Covington <cov@...eaurora.org>
>

Thanks for testing.

I found the when CPU_PM is disabled, build triggers a warning. I will
move gic_dist_security_disabled inside the ifdef CPU_PM and post v2.

-- 
Regards,
Sudeep