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From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: Abhijeet Dharmapurikar <adharmap@codeaurora.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC PATCH 1/3] genirq: add support for per-cpu dev_id interrupts
Date: Mon, 19 Sep 2011 16:05:26 +0100	[thread overview]
Message-ID: <20110919150526.GV16381@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <4E775912.3060502@arm.com>

On Mon, Sep 19, 2011 at 04:00:34PM +0100, Marc Zyngier wrote:
> Replying to myself after a quick investigation... Looks like the Qualcomm
> implementation does exactly what is mentioned above:
> 
> arch/arm/mach-msm/platsmp.c:
> void __cpuinit platform_secondary_init(unsigned int cpu)
> {
> 	/* Configure edge-triggered PPIs */
> 	writel(GIC_PPI_EDGE_MASK, MSM_QGIC_DIST_BASE + GIC_DIST_CONFIG + 4);
> 	[...]
> 
> The way I understand it, this "MSM_QGIC_DIST_BASE + GIC_DIST_CONFIG + 4"
> is a banked register (otherwise we would not do it in platform_secondary_init(),
> right?) So doing a set_type() from __setup_irq() would be just wrong. It really
> needs to be done on a per-CPU basis.

All the registers to do with the first 32 interrupts in the distributer
are banked - the enable, configuration, and priority registers are all
only accessible to the specific CPU which owns the PPIs and SGIs.

  reply	other threads:[~2011-09-19 15:05 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-15 16:52 [RFC PATCH 0/3] genirq: handling GIC per-cpu interrupts Marc Zyngier
2011-09-15 16:52 ` [RFC PATCH 1/3] genirq: add support for per-cpu dev_id interrupts Marc Zyngier
2011-09-15 21:36   ` Michał Mirosław
2011-09-16  8:20     ` Marc Zyngier
2011-09-16  9:37       ` Thomas Gleixner
2011-09-15 22:49   ` Thomas Gleixner
2011-09-15 23:29     ` Russell King - ARM Linux
2011-09-15 23:41       ` Thomas Gleixner
2011-09-16  9:37     ` Marc Zyngier
2011-09-16  9:41       ` Thomas Gleixner
2011-09-18 23:20   ` Abhijeet Dharmapurikar
2011-09-19  9:28     ` Marc Zyngier
2011-09-19 15:00       ` Marc Zyngier
2011-09-19 15:05         ` Russell King - ARM Linux [this message]
2011-09-19 15:24           ` Marc Zyngier
2011-09-26  1:31       ` Abhijeet Dharmapurikar
2011-09-26  1:58         ` Abhijeet Dharmapurikar
2011-09-15 16:52 ` [RFC PATCH 2/3] ARM: gic: consolidate PPI handling Marc Zyngier
2011-09-15 16:52 ` [RFC PATCH 3/3] ARM: gic, local timers: use the request_percpu_irq() interface Marc Zyngier

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