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From: Michal Simek <monstr@monstr.eu>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, Marc Zyngier <marc.zyngier@arm.com>,
	Grant Likely <grant.likely@secretlab.ca>,
	Will Deacon <will.deacon@arm.com>,
	Rob Herring <rob.herring@calxeda.com>,
	Nicolas Pitre <nicolas.pitre@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	Ohad Ben-Cohen <ohad@wizery.com>,
	Peter Crosthwaite <peter.crosthwaite@petalogix.com>
Subject: Re: [RFC PATCH 1/8] ARM: gic: Support forcing cpumask for possible cpus in the system
Date: Mon, 18 Jun 2012 13:41:52 +0200	[thread overview]
Message-ID: <4FDF1400.6090402@monstr.eu> (raw)
In-Reply-To: <20120618113339.GC12029@n2100.arm.linux.org.uk>

On 06/18/2012 01:33 PM, Russell King - ARM Linux wrote:
> On Mon, Jun 18, 2012 at 01:30:04PM +0200, Michal Simek wrote:
>> gic_set_affinity doesn't support force option. Force option
>> should work with all possible cpus in the system not only with
>> online cpus.
>
> Neither does x86.  Why do you want this?  Offline CPUs are unable to
> receive the interrupt in any case (and must not receive interrupts in
> the bringup path until they are online.)

The whole reason for all these changes in AMP on dual core Cortex A9 where
on one cpu runs Linux and on the second RTOS/standlone.

It means that the second cpu is from Linux point of view offline all the time.
But GIC has to be (and can be) setup to forward IRQ directly to the second cpu.
GIC should be controlled by Linux.

Thanks,
Michal




-- 
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian

WARNING: multiple messages have this Message-ID (diff)
From: monstr@monstr.eu (Michal Simek)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 1/8] ARM: gic: Support forcing cpumask for possible cpus in the system
Date: Mon, 18 Jun 2012 13:41:52 +0200	[thread overview]
Message-ID: <4FDF1400.6090402@monstr.eu> (raw)
In-Reply-To: <20120618113339.GC12029@n2100.arm.linux.org.uk>

On 06/18/2012 01:33 PM, Russell King - ARM Linux wrote:
> On Mon, Jun 18, 2012 at 01:30:04PM +0200, Michal Simek wrote:
>> gic_set_affinity doesn't support force option. Force option
>> should work with all possible cpus in the system not only with
>> online cpus.
>
> Neither does x86.  Why do you want this?  Offline CPUs are unable to
> receive the interrupt in any case (and must not receive interrupts in
> the bringup path until they are online.)

The whole reason for all these changes in AMP on dual core Cortex A9 where
on one cpu runs Linux and on the second RTOS/standlone.

It means that the second cpu is from Linux point of view offline all the time.
But GIC has to be (and can be) setup to forward IRQ directly to the second cpu.
GIC should be controlled by Linux.

Thanks,
Michal




-- 
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian

  reply	other threads:[~2012-06-18 11:41 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-18 11:30 ARM SMP/GIC/LDS patches for Xilinx Zynq remoteproc Michal Simek
2012-06-18 11:30 ` Michal Simek
2012-06-18 11:30 ` [RFC PATCH 1/8] ARM: gic: Support forcing cpumask for possible cpus in the system Michal Simek
2012-06-18 11:30   ` Michal Simek
2012-06-18 11:33   ` Russell King - ARM Linux
2012-06-18 11:33     ` Russell King - ARM Linux
2012-06-18 11:41     ` Michal Simek [this message]
2012-06-18 11:41       ` Michal Simek
2012-06-20  6:48       ` Michal Simek
2012-06-18 11:30 ` [RFC PATCH 2/8] ARM: gic: Export gic_raise_softirq function for kernel modules Michal Simek
2012-06-18 11:30   ` Michal Simek
2012-06-18 11:30 ` [RFC PATCH 3/8] ARM: gic: Introduce new gic_set_cpu Michal Simek
2012-06-18 11:30   ` Michal Simek
2012-06-18 11:30 ` [RFC PATCH 4/8] ARM: smp: Move cpu initialization directly to ipi_cpu_stop Michal Simek
2012-06-18 11:30   ` Michal Simek
2012-06-18 11:34   ` Russell King - ARM Linux
2012-06-18 11:34     ` Russell King - ARM Linux
2012-06-18 11:53     ` Michal Simek
2012-06-18 11:53       ` Michal Simek
2012-06-18 11:30 ` [RFC PATCH 5/8] AMP: smp: Extend number of IPIs Michal Simek
2012-06-18 11:30   ` Michal Simek
2012-06-18 11:35   ` Russell King - ARM Linux
2012-06-18 11:35     ` Russell King - ARM Linux
2012-06-18 11:54     ` Michal Simek
2012-06-18 11:54       ` Michal Simek
2012-06-18 11:30 ` [RFC PATCH 6/8] ARM: smp: Use generic API for ipi Michal Simek
2012-06-18 11:30   ` Michal Simek
2012-06-18 11:36   ` Russell King - ARM Linux
2012-06-18 11:36     ` Russell King - ARM Linux
2012-06-18 11:54     ` Michal Simek
2012-06-18 11:54       ` Michal Simek
2012-06-18 11:30 ` [RFC PATCH 7/8] ARM: vmlinux.lds: Setup physical load address not virtual Michal Simek
2012-06-18 11:30   ` Michal Simek
2012-06-18 14:06   ` Nicolas Pitre
2012-06-18 14:06     ` Nicolas Pitre
2012-06-18 18:15     ` Michal Simek
2012-06-18 19:02       ` Nicolas Pitre
2012-06-18 19:02         ` Nicolas Pitre
2012-06-18 19:23         ` Michal Simek
2012-06-18 19:23           ` Michal Simek
2012-06-18 21:10           ` Nicolas Pitre
2012-06-18 21:10             ` Nicolas Pitre
2012-06-19  4:16             ` Michal Simek
2012-06-18 11:30 ` [RFC PATCH 8/8] ARM: vmlinux.lds: Setup correct entry point to physical address Michal Simek
2012-06-18 11:30   ` Michal Simek
2012-06-18 11:37   ` Russell King - ARM Linux
2012-06-18 11:37     ` Russell King - ARM Linux
2012-06-18 11:45     ` Michal Simek
2012-06-18 11:45       ` Michal Simek

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