From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
Rob Herring <robh@kernel.org>,
rjw@rjwysocki.net, lukasz.luba@arm.com, heiko@sntech.de,
arnd@linaro.org, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org,
Geert Uytterhoeven <geert+renesas@glider.be>,
"moderated list:ARM/Rockchip SoC support"
<linux-arm-kernel@lists.infradead.org>,
"open list:ARM/Rockchip SoC support"
<linux-rockchip@lists.infradead.org>
Subject: Re: [PATCH v5 5/6] rockchip/soc/drivers: Add DTPM description for rk3399
Date: Tue, 4 Jan 2022 10:29:09 +0100 [thread overview]
Message-ID: <CAMuHMdXzs9WMksQAJXdYaQndsqK3CnQZTGYw=TSFVrDEdX8PCA@mail.gmail.com> (raw)
In-Reply-To: <CAPDyKFqWUJTKte3dM=7xG6EtKR8i9neCCNYFs7Jf1J34TezUEQ@mail.gmail.com>
On Fri, Dec 31, 2021 at 2:58 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
> On Sat, 18 Dec 2021 at 14:00, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
> > The DTPM framework does support now the hierarchy description.
> >
> > The platform specific code can call the hierarchy creation function
> > with an array of struct dtpm_node pointing to their parent.
> >
> > This patch provides a description of the big and Little CPUs and the
> > GPU and tie them together under a virtual package name. Only rk3399 is
> > described now.
> >
> > The description could be extended in the future with the memory
> > controller with devfreq if it has the energy information.
> >
> > The hierarchy uses the GPU devfreq with the panfrost driver, and this
> > one could be loaded as a module. If the hierarchy is created before
> > the panfrost driver is loaded, it will fail. For this reason the
> > Kconfig option depends on the panfrost Kconfig's option. If this one
> > is compiled as a module, automatically the dtpm hierarchy code will be
> > a module also. Module loading ordering will fix this chicken-egg
> > problem.
> >
> > Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> > --- /dev/null
> > +++ b/drivers/soc/rockchip/dtpm.c
> > @@ -0,0 +1,56 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Copyright 2021 Linaro Limited
> > + *
> > + * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
> > + *
> > + * DTPM hierarchy description
> > + */
> > +#include <linux/dtpm.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +
> > +static struct dtpm_node __initdata rk3399_hierarchy[] = {
> > + [0]{ .name = "rk3399" },
> > + [1]{ .name = "package",
> > + .parent = &rk3399_hierarchy[0] },
> > + [2]{ .name = "/cpus/cpu@0",
> > + .type = DTPM_NODE_DT,
> > + .parent = &rk3399_hierarchy[1] },
> > + [3]{ .name = "/cpus/cpu@1",
> > + .type = DTPM_NODE_DT,
> > + .parent = &rk3399_hierarchy[1] },
> > + [4]{ .name = "/cpus/cpu@2",
> > + .type = DTPM_NODE_DT,
> > + .parent = &rk3399_hierarchy[1] },
> > + [5]{ .name = "/cpus/cpu@3",
> > + .type = DTPM_NODE_DT,
> > + .parent = &rk3399_hierarchy[1] },
> > + [6]{ .name = "/cpus/cpu@100",
> > + .type = DTPM_NODE_DT,
> > + .parent = &rk3399_hierarchy[1] },
> > + [7]{ .name = "/cpus/cpu@101",
> > + .type = DTPM_NODE_DT,
> > + .parent = &rk3399_hierarchy[1] },
> > + [8]{ .name = "rockchip,rk3399-mali",
> > + .type = DTPM_NODE_DT,
> > + .parent = &rk3399_hierarchy[1] },
> > + [9]{ },
> > +};
>
> I will not object to this, as in the end this seems like what we need
> to do, unless we can describe things through generic DT bindings for
> DTPM. Right?
>
> Although, if the above is correct, I need to stress that I am kind of
> worried that this doesn't really scale. We would need to copy lots of
> information from the DTS files into platform specific c-files, to be
> able to describe the DTPM hierarchy.
The description in rk3399_hierarchy[] looks fairly similar to a
power-domains hierarchy, like we have in e.g. the various
drivers/soc/renesas/r8*-sysc.c files. One big difference is that the
latter do not hardcode the node paths in the driver, but use power
domain indices, referenced from DT in power-domains properties.
Perhaps a similar approach can be used for DTPM?
Does DTPM differ a lot from PM Domains? If not, perhaps no new
properties are needed, and power-domains/#power-domain-cells can be
used as is?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2022-01-04 9:29 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-18 13:00 [PATCH v5 0/6] powercap/drivers/dtpm: Create the dtpm hierarchy Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 1/6] powercap/drivers/dtpm: Move dtpm table from init to data section Daniel Lezcano
2021-12-31 13:33 ` Ulf Hansson
2022-01-04 8:57 ` Daniel Lezcano
2022-01-07 13:15 ` Daniel Lezcano
2022-01-07 14:49 ` Ulf Hansson
2022-01-10 13:33 ` Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 2/6] powercap/drivers/dtpm: Add hierarchy creation Daniel Lezcano
2021-12-31 13:45 ` Ulf Hansson
2022-01-05 16:00 ` Daniel Lezcano
2022-01-07 15:54 ` Ulf Hansson
2022-01-10 15:55 ` Daniel Lezcano
2022-01-11 8:28 ` Ulf Hansson
2022-01-11 17:52 ` Daniel Lezcano
2022-01-12 12:00 ` Ulf Hansson
2022-01-14 19:15 ` Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 3/6] powercap/drivers/dtpm: Add CPU DT initialization support Daniel Lezcano
2021-12-31 13:46 ` Ulf Hansson
2021-12-18 13:00 ` [PATCH v5 4/6] powercap/drivers/dtpm: Add dtpm devfreq with energy model support Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 5/6] rockchip/soc/drivers: Add DTPM description for rk3399 Daniel Lezcano
2021-12-31 13:57 ` Ulf Hansson
2022-01-04 9:29 ` Geert Uytterhoeven [this message]
2022-01-05 9:21 ` Daniel Lezcano
2022-01-05 11:25 ` Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 6/6] qcom/soc/drivers: Add DTPM description for sdm845 Daniel Lezcano
2021-12-18 19:47 ` Steev Klimaszewski
2021-12-18 20:11 ` Daniel Lezcano
2021-12-19 18:44 ` Steev Klimaszewski
2021-12-19 20:27 ` Daniel Lezcano
2022-01-07 19:27 ` Bjorn Andersson
2022-01-07 22:07 ` Daniel Lezcano
2022-01-07 23:51 ` Bjorn Andersson
2021-12-23 13:20 ` [PATCH v5 0/6] powercap/drivers/dtpm: Create the dtpm hierarchy Daniel Lezcano
2021-12-23 13:32 ` Ulf Hansson
2021-12-23 13:42 ` Daniel Lezcano
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