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From: Sudeep Holla <sudeep.holla@arm.com>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	linux-pm@vger.kernel.org, Stephen Boyd <sboyd@kernel.org>,
	linux-arm-msm@vger.kernel.org,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Lina Iyer <ilina@codeaurora.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Kevin Hilman <khilman@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Lina Iyer <lina.iyer@linaro.org>,
	Sudeep Holla <sudeep.holla@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 02/13] dt: psci: Update DT bindings to support hierarchical PSCI states
Date: Thu, 24 Oct 2019 16:26:16 +0100	[thread overview]
Message-ID: <20191024152504.GA11467@bogus> (raw)
In-Reply-To: <20191010113937.15962-3-ulf.hansson@linaro.org>

On Thu, Oct 10, 2019 at 01:39:26PM +0200, Ulf Hansson wrote:
> Update PSCI DT bindings to allow to represent idle states for CPUs and the
> CPU topology, by using a hierarchical layout. Primarily this is done by
> re-using the existing power domain description [1] and the domain idle
> state description [2].
>
> Let's also take the opportunity to update the examples to clarify the
> difference between the currently supported flattened layout vs the new
> hierarchical layout.
>

This looks fine to me. FWIW:

Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>

But before this gets merged, I would like to add another but "the golden"
example Qcom *always* referred during ACPI LPI discussions. Ofcourse, it
can be addition patch and if I get time, I can write this but no promise
ATM.

Hierarchical Representation:
System
1. SYSTEM_RET
2. SYSTEM_PG

	Cluster#0
	1. CLUSTER_RET
	2. CLUSTER_PG

		Core#0
		1. CORE_CG
		2. CORE_RET
		3. CORE_PG

		Core#1
		1. CORE_CG
		2. CORE_RET
		3. CORE_PG
	Cluster#1 (ditto)

Flattened Representation:

Core#0
	1 CORE_CG
	2 CORE_RET
	3 CORE_RET + CLUSTER_RET
	4 CORE_RET + CLUSTER_RET + SYSTEM_RET
	5 CORE_PG
	6 CORE_PG  + CLUSTER_RET
	7 CORE_PG  + CLUSTER_RET + SYSTEM_RET
	8 CORE_PG  + CLUSTER_PG
	9 CORE_PG  + CLUSTER_PG  + SYSTEM_RET
       10 CORE_PG  + CLUSTER_PG  + SYSTEM_PG

Though we may not implement everything needed to support this, but
we must ensure we don't have to end up in a situation breaking backward
compatibility trying to support the same.

--
Regards,
Sudeep

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  reply	other threads:[~2019-10-24 15:26 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-10 11:39 [PATCH 00/13] cpuidle: psci: Support hierarchical CPU arrangement Ulf Hansson
2019-10-10 11:39 ` [PATCH 01/13] cpuidle: psci: Fix potential access to unmapped memory Ulf Hansson
2019-10-18  9:38   ` Lorenzo Pieralisi
2019-10-18  9:51     ` Ulf Hansson
2019-10-18 10:03       ` Lorenzo Pieralisi
2019-10-18 10:29         ` Ulf Hansson
2019-10-18 16:47           ` Lorenzo Pieralisi
2019-10-24 15:18   ` [PATCH] cpuidle: psci: Align psci_power_state count with idle state count Sudeep Holla
2019-10-24 16:10     ` Ulf Hansson
2019-10-27  2:20       ` Sudeep Holla
2019-10-10 11:39 ` [PATCH 02/13] dt: psci: Update DT bindings to support hierarchical PSCI states Ulf Hansson
2019-10-24 15:26   ` Sudeep Holla [this message]
2019-10-24 16:23     ` Ulf Hansson
2019-10-10 11:39 ` [PATCH 03/13] firmware: psci: Export functions to manage the OSI mode Ulf Hansson
2019-10-24 15:27   ` Sudeep Holla
2019-10-10 11:39 ` [PATCH 04/13] of: base: Add of_get_cpu_state_node() to get idle states for a CPU node Ulf Hansson
2019-10-24 15:28   ` Sudeep Holla
2019-10-10 11:39 ` [PATCH 05/13] cpuidle: dt: Support hierarchical CPU idle states Ulf Hansson
2019-10-24 15:30   ` Sudeep Holla
2019-10-10 11:39 ` [PATCH 06/13] cpuidle: psci: Simplify OF parsing of CPU idle state nodes Ulf Hansson
2019-10-24 15:36   ` Sudeep Holla
2019-10-24 16:33     ` Ulf Hansson
2019-10-27  2:24       ` Sudeep Holla
2019-10-10 11:39 ` [PATCH 07/13] cpuidle: psci: Support hierarchical CPU idle states Ulf Hansson
2019-10-24 15:39   ` Sudeep Holla
2019-10-10 11:39 ` [PATCH 08/13] cpuidle: psci: Prepare to use OS initiated suspend mode via PM domains Ulf Hansson
2019-10-24 15:42   ` Sudeep Holla
2019-10-24 17:01     ` Ulf Hansson
2019-10-10 11:39 ` [PATCH 09/13] cpuidle: psci: Add support for PM domains by using genpd Ulf Hansson
2019-10-24 15:46   ` Sudeep Holla
2019-10-10 11:39 ` [PATCH 10/13] cpuidle: psci: Add a helper to attach a CPU to its PM domain Ulf Hansson
2019-10-24 16:31   ` Sudeep Holla
2019-10-24 16:47     ` Ulf Hansson
2019-10-27  2:30       ` Sudeep Holla
2019-10-28  7:35         ` Ulf Hansson
2019-10-28  7:49           ` Sudeep Holla
2019-10-28  9:45             ` Ulf Hansson
2019-10-29  5:34               ` Sudeep Holla
2019-10-29  9:44                 ` Niklas Cassel
2019-10-30  0:50                   ` Sudeep Holla
2019-10-10 11:39 ` [PATCH 11/13] cpuidle: psci: Attach CPU devices to their PM domains Ulf Hansson
2019-10-24 16:35   ` Sudeep Holla
2019-10-24 16:55     ` Ulf Hansson
2019-10-27  2:32       ` Sudeep Holla
2019-10-10 11:39 ` [PATCH 12/13] cpuidle: psci: Manage runtime PM in the idle path Ulf Hansson
2019-10-24 16:32   ` Sudeep Holla
2019-10-24 17:00     ` Ulf Hansson
2019-10-25  8:28       ` Lorenzo Pieralisi
2019-10-25 14:13         ` Ulf Hansson
2019-10-27  2:34       ` Sudeep Holla
2019-10-28 22:40         ` Ulf Hansson
2019-10-10 11:39 ` [PATCH 13/13] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916 Ulf Hansson
2019-10-24 16:41   ` Sudeep Holla
2019-10-24 17:03     ` Ulf Hansson
2019-10-18  8:10 ` [PATCH 00/13] cpuidle: psci: Support hierarchical CPU arrangement Ulf Hansson

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