From: Ulf Hansson <ulf.hansson@linaro.org>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: "Dmitry Osipenko" <digetx@gmail.com>,
"Jonathan Hunter" <jonathanh@nvidia.com>,
"Viresh Kumar" <vireshk@kernel.org>,
"Stephen Boyd" <sboyd@kernel.org>,
"Peter De Schrijver" <pdeschrijver@nvidia.com>,
"Mikko Perttunen" <mperttunen@nvidia.com>,
"Peter Chen" <peter.chen@kernel.org>,
"Mark Brown" <broonie@kernel.org>,
"Lee Jones" <lee.jones@linaro.org>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Nishanth Menon" <nm@ti.com>,
"Vignesh Raghavendra" <vigneshr@ti.com>,
"Richard Weinberger" <richard@nod.at>,
"Miquel Raynal" <miquel.raynal@bootlin.com>,
"Lucas Stach" <dev@lynxeye.de>, "Stefan Agner" <stefan@agner.ch>,
"Adrian Hunter" <adrian.hunter@intel.com>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>,
"Rob Herring" <robh+dt@kernel.org>,
"Michael Turquette" <mturquette@baylibre.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
linux-tegra <linux-tegra@vger.kernel.org>,
"Linux PM" <linux-pm@vger.kernel.org>,
"Linux USB List" <linux-usb@vger.kernel.org>,
linux-staging@lists.linux.dev, linux-spi@vger.kernel.org,
linux-pwm@vger.kernel.org, linux-mtd@lists.infradead.org,
linux-mmc <linux-mmc@vger.kernel.org>,
"Linux Media Mailing List" <linux-media@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
DTML <devicetree@vger.kernel.org>,
linux-clk <linux-clk@vger.kernel.org>
Subject: Re: [PATCH v8 11/34] gpu: host1x: Add runtime PM and OPP support
Date: Wed, 18 Aug 2021 10:35:11 +0200 [thread overview]
Message-ID: <CAPDyKFp+9Bv3EVSnV683ixNXzukJtmG_QrS5C1ZQqLxv9QJ-bQ@mail.gmail.com> (raw)
In-Reply-To: <YRvBkyfFCqthBIBV@orome.fritz.box>
On Tue, 17 Aug 2021 at 16:03, Thierry Reding <thierry.reding@gmail.com> wrote:
>
> On Tue, Aug 17, 2021 at 02:04:38PM +0200, Ulf Hansson wrote:
> > On Tue, 17 Aug 2021 at 03:30, Dmitry Osipenko <digetx@gmail.com> wrote:
> > >
> > > Add runtime PM and OPP support to the Host1x driver. It's required for
> > > enabling system-wide DVFS and supporting dynamic power management using
> > > a generic power domain. For the starter we will keep host1x always-on
> > > because dynamic power management require a major refactoring of the driver
> > > code since lot's of code paths will need the RPM handling and we're going
> > > to remove some of these paths in the future. Host1x doesn't consume much
> > > power so it is good enough, we at least need to resume Host1x in order
> > > to initialize the power state.
> > >
> > > Tested-by: Peter Geis <pgwipeout@gmail.com> # Ouya T30
> > > Tested-by: Paul Fertser <fercerpav@gmail.com> # PAZ00 T20
> > > Tested-by: Nicolas Chauvet <kwizart@gmail.com> # PAZ00 T20 and TK1 T124
> > > Tested-by: Matt Merhar <mattmerhar@protonmail.com> # Ouya T30
> > > Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> > > ---
> >
> > [...]
> >
> > > +
> > > static int host1x_probe(struct platform_device *pdev)
> > > {
> > > struct host1x *host;
> > > @@ -394,6 +423,10 @@ static int host1x_probe(struct platform_device *pdev)
> > > /* set common host1x device data */
> > > platform_set_drvdata(pdev, host);
> > >
> > > + err = devm_tegra_core_dev_init_opp_table_simple(&pdev->dev);
> > > + if (err)
> > > + return err;
> > > +
> > > host->regs = devm_ioremap_resource(&pdev->dev, regs);
> > > if (IS_ERR(host->regs))
> > > return PTR_ERR(host->regs);
> > > @@ -423,12 +456,9 @@ static int host1x_probe(struct platform_device *pdev)
> > > return err;
> > > }
> > >
> > > - host->rst = devm_reset_control_get(&pdev->dev, "host1x");
> > > - if (IS_ERR(host->rst)) {
> > > - err = PTR_ERR(host->rst);
> > > - dev_err(&pdev->dev, "failed to get reset: %d\n", err);
> > > + err = host1x_get_resets(host);
> > > + if (err)
> > > return err;
> > > - }
> > >
> > > err = host1x_iommu_init(host);
> > > if (err < 0) {
> > > @@ -443,22 +473,10 @@ static int host1x_probe(struct platform_device *pdev)
> > > goto iommu_exit;
> > > }
> > >
> > > - err = clk_prepare_enable(host->clk);
> > > - if (err < 0) {
> > > - dev_err(&pdev->dev, "failed to enable clock\n");
> > > - goto free_channels;
> > > - }
> > > -
> > > - err = reset_control_deassert(host->rst);
> > > - if (err < 0) {
> > > - dev_err(&pdev->dev, "failed to deassert reset: %d\n", err);
> > > - goto unprepare_disable;
> > > - }
> > > -
> >
> > Removing the clk_prepare_enable() and reset_control_deassert() from
> > host1x_probe(), might not be a good idea. See more about why, below.
> >
> > > err = host1x_syncpt_init(host);
> > > if (err) {
> > > dev_err(&pdev->dev, "failed to initialize syncpts\n");
> > > - goto reset_assert;
> > > + goto free_channels;
> > > }
> > >
> > > err = host1x_intr_init(host, syncpt_irq);
> > > @@ -467,10 +485,14 @@ static int host1x_probe(struct platform_device *pdev)
> > > goto deinit_syncpt;
> > > }
> > >
> > > - host1x_debug_init(host);
> > > + pm_runtime_enable(&pdev->dev);
> > >
> > > - if (host->info->has_hypervisor)
> > > - host1x_setup_sid_table(host);
> > > + /* the driver's code isn't ready yet for the dynamic RPM */
> > > + err = pm_runtime_resume_and_get(&pdev->dev);
> >
> > If the driver is being built with the CONFIG_PM Kconfig option being
> > unset, pm_runtime_resume_and_get() will return 0 to indicate success -
> > and without calling the ->runtime_resume() callback.
> > In other words, the clock will remain gated and the reset will not be
> > deasserted, likely causing the driver to be malfunctioning.
> >
> > If the driver isn't ever being built with CONFIG_PM unset, feel free
> > to ignore my above comments.
> >
> > Otherwise, if it needs to work both with and without CONFIG_PM being
> > set, you may use the following pattern in host1x_probe() to deploy
> > runtime PM support:
> >
> > "Enable the needed resources to probe the device"
> > pm_runtime_get_noresume()
> > pm_runtime_set_active()
> > pm_runtime_enable()
> >
> > "Before successfully completing probe"
> > pm_runtime_put()
>
> We made a conscious decision a few years ago to have ARCH_TEGRA select
> PM on both 32-bit and 64-bit ARM, specifically to avoid the need to do
> this dance (though there are still a few drivers left that do this, I
> think).
>
> So I think this should be unnecessary. Unless perhaps if the sysfs PM
> controls have any influence on this. As far as I know, as long as the
> PM kconfig option is enabled, the sysfs control only influence the
> runtime behaviour (i.e. setting the sysfs PM control to "on" is going
> to force runtime PM to be resumed) but there's no way to disable
> runtime PM altogether via sysfs that would make the above necessary.
Thanks for clarifying! As I said, feel free to ignore my comments then.
For this and the other patches in the series, I assume you only need
to care about whether the driver is a cross SoC driver and used on
other platforms than Tegra then.
>
> Thierry
Kind regards
Uffe
next prev parent reply other threads:[~2021-08-18 8:35 UTC|newest]
Thread overview: 119+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-17 1:27 [PATCH v8 00/34] NVIDIA Tegra power management patches for 5.16 Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 01/34] opp: Add dev_pm_opp_sync() helper Dmitry Osipenko
2021-08-17 7:55 ` Viresh Kumar
2021-08-17 15:49 ` Dmitry Osipenko
2021-08-18 3:55 ` Viresh Kumar
2021-08-18 4:12 ` Dmitry Osipenko
2021-08-18 4:29 ` Dmitry Osipenko
2021-08-18 4:30 ` Dmitry Osipenko
2021-08-18 4:34 ` Viresh Kumar
2021-08-18 4:31 ` Viresh Kumar
2021-08-18 4:37 ` Dmitry Osipenko
2021-08-18 4:53 ` Viresh Kumar
2021-08-18 5:21 ` Dmitry Osipenko
2021-08-18 5:58 ` Viresh Kumar
2021-08-18 6:00 ` Viresh Kumar
2021-08-18 6:22 ` Dmitry Osipenko
2021-08-18 6:27 ` Viresh Kumar
2021-08-18 8:29 ` Ulf Hansson
2021-08-18 9:14 ` Viresh Kumar
2021-08-18 9:41 ` Ulf Hansson
2021-08-18 9:42 ` Ulf Hansson
2021-08-18 9:50 ` Viresh Kumar
2021-08-18 10:08 ` Ulf Hansson
2021-08-18 15:43 ` Dmitry Osipenko
2021-08-18 15:46 ` Dmitry Osipenko
2021-08-19 13:07 ` Ulf Hansson
2021-08-19 19:35 ` Dmitry Osipenko
2021-08-20 5:07 ` Viresh Kumar
2021-08-20 12:42 ` Ulf Hansson
2021-08-21 17:34 ` Dmitry Osipenko
2021-08-23 10:46 ` Ulf Hansson
2021-08-23 15:54 ` Dmitry Osipenko
2021-08-18 15:55 ` Dmitry Osipenko
2021-08-19 6:16 ` Viresh Kumar
2021-08-19 14:55 ` Ulf Hansson
2021-08-20 5:18 ` Viresh Kumar
2021-08-20 12:57 ` Ulf Hansson
2021-08-23 20:24 ` Dmitry Osipenko
2021-08-24 3:04 ` Viresh Kumar
2021-08-22 18:35 ` Dmitry Osipenko
2021-08-25 15:41 ` Dmitry Osipenko
2021-08-26 2:54 ` Viresh Kumar
2021-08-26 2:55 ` Viresh Kumar
2021-08-17 1:27 ` [PATCH v8 02/34] soc/tegra: pmc: Disable PMC state syncing Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 03/34] soc/tegra: Don't print error message when OPPs not available Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 04/34] soc/tegra: Add devm_tegra_core_dev_init_opp_table_simple() Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 05/34] soc/tegra: Use dev_pm_opp_sync() Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 06/34] dt-bindings: clock: tegra-car: Document new tegra-clocks sub-node Dmitry Osipenko
2021-08-18 1:15 ` Rob Herring
2021-08-18 1:44 ` Dmitry Osipenko
2021-08-18 13:52 ` Thierry Reding
2021-08-18 15:04 ` Dmitry Osipenko
2021-08-18 13:59 ` Thierry Reding
2021-08-18 15:05 ` Dmitry Osipenko
2021-08-18 16:39 ` Thierry Reding
2021-08-18 16:57 ` Dmitry Osipenko
2021-08-18 17:16 ` Dmitry Osipenko
2021-08-19 16:31 ` Thierry Reding
2021-08-19 22:20 ` Dmitry Osipenko
2021-08-20 2:51 ` Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 07/34] clk: tegra: Support runtime PM and power domain Dmitry Osipenko
2021-08-18 14:07 ` Thierry Reding
2021-08-18 15:05 ` Dmitry Osipenko
2021-08-18 16:42 ` Thierry Reding
2021-08-18 17:11 ` Dmitry Osipenko
2021-08-19 16:54 ` Thierry Reding
2021-08-19 22:09 ` Dmitry Osipenko
2021-08-20 11:42 ` Thierry Reding
2021-08-20 13:08 ` Ulf Hansson
2021-08-21 17:45 ` Dmitry Osipenko
2021-08-23 14:33 ` Thierry Reding
2021-08-23 18:54 ` Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 08/34] dt-bindings: host1x: Document OPP and power domain properties Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 09/34] dt-bindings: host1x: Document Memory Client resets of Host1x, GR2D and GR3D Dmitry Osipenko
2021-08-18 1:16 ` Rob Herring
2021-08-18 1:37 ` Dmitry Osipenko
2021-08-18 2:04 ` Dmitry Osipenko
2021-08-18 2:07 ` Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 10/34] gpu: host1x: Add host1x_channel_stop() Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 11/34] gpu: host1x: Add runtime PM and OPP support Dmitry Osipenko
2021-08-17 12:04 ` Ulf Hansson
2021-08-17 14:02 ` Thierry Reding
2021-08-18 8:35 ` Ulf Hansson [this message]
2021-08-18 17:24 ` Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 12/34] drm/tegra: dc: Support OPP and SoC core voltage scaling Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 13/34] drm/tegra: hdmi: Add OPP support Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 14/34] drm/tegra: gr2d: Support power management Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 15/34] drm/tegra: gr3d: " Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 16/34] drm/tegra: vic: Support system suspend Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 17/34] usb: chipidea: tegra: Add runtime PM and OPP support Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 18/34] bus: tegra-gmi: " Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 19/34] pwm: tegra: " Dmitry Osipenko
2021-08-19 13:21 ` Thierry Reding
2021-08-19 14:04 ` Ulf Hansson
2021-08-19 16:17 ` Thierry Reding
2021-08-17 1:27 ` [PATCH v8 20/34] mmc: sdhci-tegra: " Dmitry Osipenko
2021-08-19 17:03 ` Thierry Reding
2021-08-19 22:37 ` Dmitry Osipenko
2021-08-20 11:35 ` Thierry Reding
2021-08-25 9:45 ` Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 21/34] mtd: rawnand: tegra: " Dmitry Osipenko
2021-08-17 8:41 ` Miquel Raynal
2021-08-17 1:27 ` [PATCH v8 22/34] spi: tegra20-slink: Add " Dmitry Osipenko
2021-08-17 12:22 ` Mark Brown
2021-08-17 15:53 ` Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 23/34] media: dt: bindings: tegra-vde: Convert to schema Dmitry Osipenko
2021-08-18 1:17 ` Rob Herring
2021-08-17 1:27 ` [PATCH v8 24/34] media: dt: bindings: tegra-vde: Document OPP and power domain Dmitry Osipenko
2021-08-18 1:17 ` Rob Herring
2021-08-17 1:27 ` [PATCH v8 25/34] media: staging: tegra-vde: Support generic power domain and OPP Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 26/34] soc/tegra: fuse: Add OPP support Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 27/34] soc/tegra: fuse: Reset hardware Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 28/34] soc/tegra: regulators: Prepare for suspend Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 29/34] soc/tegra: pmc: Enable core domain support for Tegra20 and Tegra30 Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 30/34] ARM: tegra: Add OPP tables and power domains to Tegra20 device-trees Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 31/34] ARM: tegra: Add OPP tables and power domains to Tegra30 device-trees Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 32/34] ARM: tegra: Add Memory Client resets to Tegra20 GR2D, GR3D and Host1x Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 33/34] ARM: tegra: Add Memory Client resets to Tegra30 " Dmitry Osipenko
2021-08-17 1:27 ` [PATCH v8 34/34] ARM: tegra20/30: Disable unused host1x hardware Dmitry Osipenko
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