LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Marc Zyngier <marc.zyngier@arm.com>
To: valmiki <valmikibow@gmail.com>, linux-kernel@vger.kernel.org
Cc: tglx@linutronix.de, jason@lakedaemon.net,
	Catalin Marinas <catalin.marinas@arm.com>
Subject: Re: Affinity for GIC irq line
Date: Wed, 25 Apr 2018 08:07:31 +0100	[thread overview]
Message-ID: <2d9f0678-ec5c-2b09-7ddd-407dd37c55a1@arm.com> (raw)
In-Reply-To: <2880aee6-704c-a5aa-e193-75bba1bce43d@gmail.com>

On 25/04/18 04:23, valmiki wrote:
> Hi all,
> 
> When an IRQ line is set affinity using irq_set_affinity, which calls 
> irq_do_set_affinity, this API copies affinity mask to affinity variable 
> in irq_common_data of this irq descriptor.

It does a wee bit more. Crucially, it contains the line:

        ret = chip->irq_set_affinity(data, mask, force);

> But as per ARM GICv2 document in order to drive a interrupt to a 
> specific CPU we need to program GICD_ITARGETSRn register.
> 
> But irq_set_affinity isn't writing to this register.Please correct me if 
> I'm wrong i did not find code for this register being updated in 
> irq_set_affinity flow.
> So how affinity is being set for an IRQ line ?

I would have though that a function name such as "gic_set_affinity" was
clear enough?

> If affinity was set successfully on what CPU does asm_do_IRQ run ?

It runs on the CPU that the interrupt targets, I'd say.

	M.
-- 
Jazz is not dead. It just smells funny...

  reply	other threads:[~2018-04-25  7:07 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-25  3:23 valmiki
2018-04-25  7:07 ` Marc Zyngier [this message]
2018-04-26  3:49   ` valmiki

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=2d9f0678-ec5c-2b09-7ddd-407dd37c55a1@arm.com \
    --to=marc.zyngier@arm.com \
    --cc=catalin.marinas@arm.com \
    --cc=jason@lakedaemon.net \
    --cc=linux-kernel@vger.kernel.org \
    --cc=tglx@linutronix.de \
    --cc=valmikibow@gmail.com \
    --subject='Re: Affinity for GIC irq line' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).