Re: [PATCH] keystone: psci: adds cpu_die implementation

From: Vitaly Andrianov
Date: Thu Jun 25 2015 - 12:51:54 EST




On 06/25/2015 12:13 PM, Mark Rutland wrote:
On Thu, Jun 25, 2015 at 05:01:36PM +0100, Vitaly Andrianov wrote:


On 06/25/2015 10:59 AM, santosh shilimkar wrote:
On 6/25/2015 7:45 AM, Mark Rutland wrote:
Hi,

On Thu, Jun 25, 2015 at 03:02:50PM +0100, Vitaly Andrianov wrote:
This commit add cpu_die implementation using psci api

I don't understand. If you have a PSCI implementation, it should be
sufficient to have a PSCI node (and enable-method) in your DT, and the
generic code will be used. Nothing should be required in your board
code.

You should also use CPU_ON to bring secondaries online rather than
mixing up PSCI and platform-specific mechanisms.

Good point about CPU_ON. We need that as well.

Does it mean that keystone_defconfig must always have CONFIG_HOTPLUG_CPU
and CONFIG_ARM_PSCI enabled?

No.

You need CONFIG_ARM_PSCI for PSCI CPU_ON. Without CONFIG_HOTPLUG_CPU,
you'll get PSCI CPU_ON but not PSCI CPU_OFF.

What is if someone doesn't want to have HOTPLUG_CPU?

Then you don't get PSCI CPU_OFF, but can still have PSCI CPU_ON.

Only the portions of the PSCI code required for turning CPUs off are
dependent on HOTPLUG_CPU.

How he can boot secondary CPU w/o platform-specific mechanizm?

By using PSCI CPU_ON.

Thanks,
Mark
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Thanks Mark,

I need rework and re-test the patch.
One more question. Shall I post the dts related commit, which add PSCI command together with this commit? Or it may be posted later independently?

Thanks,
Vitaly

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