Linux-PM Archive on lore.kernel.org
 help / color / Atom feed
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 <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>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Linux PM <linux-pm@vger.kernel.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Lina Iyer <lina.iyer@linaro.org>
Subject: Re: [PATCH 09/18] drivers: firmware: psci: Add support for PM domains using genpd
Date: Mon, 10 Jun 2019 11:59:03 +0100
Message-ID: <20190610105903.GC26602@e107155-lin> (raw)
In-Reply-To: <CAPDyKFq3FFZEAEKrPfvBPUpAGKaTo05zS0-5sfgBjGFhRZ0b=w@mail.gmail.com>

On Mon, Jun 10, 2019 at 12:21:41PM +0200, Ulf Hansson wrote:
> On Fri, 7 Jun 2019 at 17:27, Sudeep Holla <sudeep.holla@arm.com> wrote:
> >
> > On Mon, May 13, 2019 at 09:22:51PM +0200, Ulf Hansson wrote:
> > > When the hierarchical CPU topology layout is used in DT, we need to setup
> > > the corresponding PM domain data structures, as to allow a CPU and a group
> > > of CPUs to be power managed accordingly. Let's enable this by deploying
> > > support through the genpd interface.
> > >
> > > Additionally, when the OS initiated mode is supported by the PSCI FW, let's
> > > also parse the domain idle states DT bindings as to make genpd responsible
> > > for the state selection, when the states are compatible with
> > > "domain-idle-state". Otherwise, when only Platform Coordinated mode is
> > > supported, we rely solely on the state selection to be managed through the
> > > regular cpuidle framework.
> > >
> > > If the initialization of the PM domain data structures succeeds and the OS
> > > initiated mode is supported, we try to switch to it. In case it fails,
> > > let's fall back into a degraded mode, rather than bailing out and returning
> > > an error code.
> > >
> > > Due to that the OS initiated mode may become enabled, we need to adjust to
> > > maintain backwards compatibility for a kernel started through a kexec call.
> > > Do this by explicitly switch to Platform Coordinated mode during boot.
> > >
> > > Finally, the actual initialization of the PM domain data structures, is
> > > done via calling the new shared function, psci_dt_init_pm_domains().
> > > However, this is implemented by subsequent changes.
> > >
> > > 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:
> > >       - Simplify code setting domain_state at power off.
> > >       - Use the genpd ->free_state() callback to manage freeing of states.
> > >       - Fixup a bogus while loop.
> > >
> > > ---
> > >  drivers/firmware/psci/Makefile         |   2 +-
> > >  drivers/firmware/psci/psci.c           |   7 +-
> > >  drivers/firmware/psci/psci.h           |   5 +
> > >  drivers/firmware/psci/psci_pm_domain.c | 268 +++++++++++++++++++++++++
> > >  4 files changed, 280 insertions(+), 2 deletions(-)
> > >  create mode 100644 drivers/firmware/psci/psci_pm_domain.c
> > >

[...]

> > > +
> > > +static int psci_pd_parse_states(struct device_node *np,
> > > +                     struct genpd_power_state **states, int *state_count)
> > > +{
> > > +     int ret;
> > > +
> > > +     /* Parse the domain idle states. */
> > > +     ret = of_genpd_parse_idle_states(np, states, state_count);
> > > +     if (ret)
> > > +             return ret;
> > > +
> >
> >
> > Lots of things here in this file are not psci specific. They can be
> > moved as generic CPU PM domain support.
>
> What exactly do you mean by CPU PM domain support?
>
> The current split is based upon how the generic PM domain (genpd)
> supports CPU devices (see GENPD_FLAG_CPU_DOMAIN), which is already
> available.
>
> I agree that finding the right balance between what can be made
> generic and driver specific is not always obvious. Often it's better
> to start with having more things in the driver code, then move things
> into a common framework, later on, when that turns out to make sense.
>

Indeed, I agree. But when reviewing this time I thought it should be
possible to push generic stuff into existing dt_idle_driver. I must
admit that I haven't thought much in details, just thought of expressing
the idea and see. But yes it's difficult to find the balance but at the
same time we need reasons to have these in psci :)


> >
> > > +     /* Fill out the PSCI specifics for each found state. */
> > > +     ret = psci_pd_parse_state_nodes(*states, *state_count);
> > > +     if (ret)
> > > +             kfree(*states);
> > > +
> >
> > Things like above are PSCI.
> >
> > I am trying to see if we can do something to achieve partitions like we
> > have today: psci.c just has PSCI specific stuff and dt_idle_states.c
> > deals with generic idle stuff.
> 
> I am open to any suggestions. Although, I am not sure I understand
> your comment and nor the reason to why you want me to change.
> 
> So, what is the problem with having the code that you refer to, inside
> drivers/firmware/psci/psci_pm_domain.c? Can't we just start with that
> and see how it plays?
> 

I need to think how to partition this well. I don't have suggestions
right away, but I need to get convinced what we have here is best we
can do or come up with a better solution. I didn't like it as is at
this time.

--
Regards,
Sudeep

  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
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 [this message]
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

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190610105903.GC26602@e107155-lin \
    --to=sudeep.holla@arm.com \
    --cc=Lorenzo.Pieralisi@arm.com \
    --cc=amit.kucheria@linaro.org \
    --cc=bjorn.andersson@linaro.org \
    --cc=daniel.lezcano@linaro.org \
    --cc=geert+renesas@glider.be \
    --cc=ilina@codeaurora.org \
    --cc=khilman@kernel.org \
    --cc=lina.iyer@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=niklas.cassel@linaro.org \
    --cc=rjw@rjwysocki.net \
    --cc=rplsssn@codeaurora.org \
    --cc=sboyd@kernel.org \
    --cc=souvik.chakravarty@arm.com \
    --cc=tony@atomide.com \
    --cc=ulf.hansson@linaro.org \
    --cc=vincent.guittot@linaro.org \
    --cc=viresh.kumar@linaro.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-PM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-pm/0 linux-pm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-pm linux-pm/ https://lore.kernel.org/linux-pm \
		linux-pm@vger.kernel.org linux-pm@archiver.kernel.org
	public-inbox-index linux-pm


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-pm


AGPL code for this site: git clone https://public-inbox.org/ public-inbox