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From: Sudeep Holla <sudeep.holla@arm.com>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	"Raju P . L . S . S . S . N" <rplsssn@codeaurora.org>,
	Amit Kucheria <amit.kucheria@linaro.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Stephen Boyd <sboyd@kernel.org>,
	Niklas Cassel <niklas.cassel@linaro.org>,
	Tony Lindgren <tony@atomide.com>,
	Kevin Hilman <khilman@kernel.org>,
	Lina Iyer <ilina@codeaurora.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Souvik Chakravarty <souvik.chakravarty@arm.com>,
	linux-pm@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-kernel@vger.kernel.org, Lina Iyer <lina.iyer@linaro.org>
Subject: Re: [PATCH 07/18] drivers: firmware: psci: Prepare to use OS initiated suspend mode
Date: Tue, 16 Jul 2019 15:53:36 +0100
Message-ID: <20190716145336.GC7250@e107155-lin> (raw)
In-Reply-To: <20190513192300.653-8-ulf.hansson@linaro.org>

On Mon, May 13, 2019 at 09:22:49PM +0200, Ulf Hansson wrote:
> The per CPU variable psci_power_state, contains an array of fixed values,
> which reflects the corresponding arm,psci-suspend-param parsed from DT, for
> each of the available CPU idle states.
>
> This isn't sufficient when using the hierarchical CPU topology in DT in
> combination with having PSCI OS initiated (OSI) mode enabled. More
> precisely, in OSI mode, Linux is responsible of telling the PSCI FW what
> idle state the cluster (a group of CPUs) should enter, while in PSCI
> Platform Coordinated (PC) mode, each CPU independently votes for an idle
> state of the cluster.
>
> For this reason, let's introduce an additional per CPU variable called
> domain_state and implement two helper functions to read/write its values.
> Following patches, which implements PM domain support for PSCI, will use
> the domain_state variable and set it to corresponding bits that represents
> the selected idle state for the cluster.
>
> Finally, in psci_cpu_suspend_enter() and psci_suspend_finisher(), let's
> take into account the values in the domain_state, as to get the complete
> suspend parameter.
>
> Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>
> Changes:
> 	- Clarify changelog.
> 	- Drop changes in psci_cpu_on() as it belongs in the patch for hotplug.
> 	- Move some code inside "#ifdef CONFIG_CPU_IDLE".
>
> ---
>  drivers/firmware/psci/psci.c | 24 ++++++++++++++++++++----
>  1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index b11560f7c4b9..4aec513136e4 100644
> --- a/drivers/firmware/psci/psci.c
> +++ b/drivers/firmware/psci/psci.c
> @@ -285,6 +285,17 @@ static int __init psci_features(u32 psci_func_id)
>
>  #ifdef CONFIG_CPU_IDLE
>  static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
> +static DEFINE_PER_CPU(u32, domain_state);
> +
> +static inline u32 psci_get_domain_state(void)
> +{
> +	return __this_cpu_read(domain_state);
> +}
> +
> +static inline void psci_set_domain_state(u32 state)
> +{
> +	__this_cpu_write(domain_state, state);
> +}
>
>  static int psci_dt_parse_state_node(struct device_node *np, u32 *state)
>  {
> @@ -420,15 +431,17 @@ int psci_cpu_init_idle(struct cpuidle_driver *drv, unsigned int cpu)
>  static int psci_suspend_finisher(unsigned long index)
>  {
>  	u32 *state = __this_cpu_read(psci_power_state);
> +	u32 composite_state = state[index - 1] | psci_get_domain_state();
>

The more I read this code and PSCI spec, I think it's not simple OR here
unless the specification states that. ACPI LPI explicitly stated that as
it was generic and PSCI doesn't. It can be made workable for original
format, but I think it's not that simple for extended format unless the
suspend parameters are carefully designed to achieve that, so we can't
just convert existing platforms the way it's shown on HiKey in this series.

--
Regards,
Sudeep

  parent reply index

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-13 19:22 [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI Ulf Hansson
2019-05-13 19:22 ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 01/18] dt: psci: Update DT bindings to support hierarchical PSCI states Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-07-19 11:29   ` Lorenzo Pieralisi
2019-05-13 19:22 ` [PATCH 02/18] of: base: Add of_get_cpu_state_node() to get idle states for a CPU node Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 03/18] cpuidle: dt: Support hierarchical CPU idle states Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 04/18] ARM/ARM64: cpuidle: Let back-end init ops take the driver as input Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:00   ` Sudeep Holla
2019-06-10 10:20     ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 05/18] drivers: firmware: psci: Simplify state node parsing Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:01   ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 06/18] drivers: firmware: psci: Support hierarchical CPU idle states Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:03   ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 07/18] drivers: firmware: psci: Prepare to use OS initiated suspend mode Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:17   ` Sudeep Holla
2019-06-10 10:21     ` Ulf Hansson
2019-06-10 10:42       ` Sudeep Holla
2019-07-16 14:53   ` Sudeep Holla [this message]
2019-05-13 19:22 ` [PATCH 08/18] drivers: firmware: psci: Prepare to support PM domains Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:21   ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 09/18] drivers: firmware: psci: Add support for PM domains using genpd Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:27   ` Sudeep Holla
2019-06-10 10:21     ` Ulf Hansson
2019-06-10 10:59       ` Sudeep Holla
2019-07-16 15:05   ` Sudeep Holla
2019-07-18 11:04     ` Ulf Hansson
2019-07-18 13:19       ` Sudeep Holla
2019-07-18 17:57         ` Lina Iyer
2019-07-19  9:45           ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 10/18] drivers: firmware: psci: Add hierarchical domain idle states converter Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-07-09 15:31   ` Lorenzo Pieralisi
2019-07-16  8:45     ` Ulf Hansson
2019-07-16 14:51       ` Lorenzo Pieralisi
2019-07-18 11:43         ` Ulf Hansson
2019-07-18 13:36           ` Lorenzo Pieralisi
2019-05-13 19:22 ` [PATCH 11/18] drivers: firmware: psci: Introduce psci_dt_topology_init() Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 12/18] drivers: firmware: psci: Add a helper to attach a CPU to its PM domain Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 13/18] drivers: firmware: psci: Attach the CPU's device " Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 14/18] drivers: firmware: psci: Manage runtime PM in the idle path for CPUs Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-07-16 15:53   ` Lorenzo Pieralisi
2019-07-18 10:35     ` Ulf Hansson
2019-07-18 13:30       ` Lorenzo Pieralisi
2019-07-18 16:54         ` Ulf Hansson
2019-07-18 17:41           ` Lina Iyer
2019-07-18 21:49             ` Ulf Hansson
2019-07-19 10:02               ` Lorenzo Pieralisi
2019-05-13 19:22 ` [PATCH 15/18] drivers: firmware: psci: Support CPU hotplug for the hierarchical model Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:31   ` Sudeep Holla
2019-06-10 10:21     ` Ulf Hansson
2019-06-10 11:02       ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 16/18] arm64: kernel: Respect the hierarchical CPU topology in DT for PSCI Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 17/18] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916 Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-07-16 14:47   ` Sudeep Holla
2019-07-16 20:36     ` Lina Iyer
2019-07-17 17:18       ` Sudeep Holla
2019-05-13 19:23 ` [PATCH 18/18] arm64: dts: hikey: Convert to the hierarchical CPU topology layout Ulf Hansson
2019-05-13 19:23   ` Ulf Hansson
2019-07-16 14:47   ` Sudeep Holla
2019-07-18 10:48     ` Ulf Hansson
2019-07-18 13:11       ` Sudeep Holla
2019-05-14  8:08 ` [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI Rafael J. Wysocki
2019-05-14  8:08   ` Rafael J. Wysocki
2019-05-14  8:58   ` Ulf Hansson
2019-05-14  8:58     ` Ulf Hansson
2019-06-07 15:42     ` Sudeep Holla
2019-06-07 19:34       ` Bjorn Andersson
2019-06-10 10:32         ` Sudeep Holla
2019-06-10 15:54           ` Ulf Hansson
2019-06-10 17:16             ` Lorenzo Pieralisi
2019-06-10 18:57               ` Ulf Hansson
2019-06-18 11:56                 ` Ulf Hansson
2019-06-07 11:19 ` Ulf Hansson

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