From: Ulf Hansson <ulf.hansson@linaro.org>
To: Jon Hunter <jonathanh@nvidia.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Kevin Hilman <khilman@kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>
Subject: Re: [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains
Date: Thu, 6 Oct 2016 14:22:12 +0200 [thread overview]
Message-ID: <CAPDyKFoFPNNnoc-7G34A7a4Yo8f=WUyurNP1evabw3MOEubEoA@mail.gmail.com> (raw)
In-Reply-To: <1474367287-10402-1-git-send-email-jonathanh@nvidia.com>
On 20 September 2016 at 12:28, Jon Hunter <jonathanh@nvidia.com> wrote:
> The Tegra124/210 XUSB subsystem (that consists of both host and device
> controllers) is partitioned across 3 PM domains which are:
> - XUSBA: Superspeed logic (for USB 3.0)
> - XUSBB: Device controller
> - XUSBC: Host controller
>
> These power domains are not nested and can be powered-up and down
> independently of one another. In practice different scenarios require
> different combinations of the power domains, for example:
> - Superspeed host: XUSBA and XUSBC
> - Superspeed device: XUSBA and XUSBB
>
> Although it could be possible to logically nest both the XUSBB and XUSBC
> domains under the XUSBA, superspeed may not always be used/required and
> so this would keep it on unnecessarily.
>
> Given that Tegra uses device-tree for describing the hardware, it would
> be ideal that the device-tree 'power-domains' property for generic PM
> domains could be extended to allow more than one PM domain to be
> specified. For example, define the following the Tegra210 xHCI device ...
>
> usb@70090000 {
> compatible = "nvidia,tegra210-xusb";
> ...
> power-domains = <&pd_xusbhost>, <&pd_xusbss>;
> };
>
> This RFC extends the generic PM domain framework to allow a device to
> define more than one PM domain in the device-tree 'power-domains'
> property.
First, I don't really like extending the internal logic of genpd to
deal with multiple PM domains per device. *If* this really is needed,
I think we should try to extend the struct device to cover this, then
make genpd to use it somehow.
Second, another way of seeing this is: Depending on the current
runtime selected configuration you need to re-configure the PM domain
topology - but the device would still remain in the same PM domain.
In other words, you would need to remove/add subdomain(s) depending on
the selected configuration. Would that better reflect the HW?
[...]
Kind regards
Uffe
next prev parent reply other threads:[~2016-10-06 12:22 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-20 10:28 [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains Jon Hunter
2016-09-20 10:28 ` [RFC PATCH 1/3] PM / Domains: Add helper functions for finding and attaching PM domains Jon Hunter
2016-09-20 10:28 ` [RFC PATCH 2/3] PM / Domains: Add support for devices with multiple domains Jon Hunter
2016-09-20 17:54 ` Jon Hunter
2016-09-21 8:53 ` Geert Uytterhoeven
2016-09-21 10:01 ` Jon Hunter
2016-09-21 14:37 ` Jon Hunter
2016-09-21 14:57 ` Geert Uytterhoeven
2016-09-23 12:57 ` Jon Hunter
2016-09-23 14:27 ` Geert Uytterhoeven
2016-09-30 8:05 ` Jon Hunter
2016-10-07 9:14 ` Kevin Hilman
2016-10-10 11:24 ` Jon Hunter
2016-09-20 10:28 ` [RFC PATCH 3/3] dt-bindings: Add support for devices with multiple PM domains Jon Hunter
2016-10-06 6:04 ` [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains Rajendra Nayak
2016-10-06 8:25 ` Jon Hunter
2016-10-06 8:43 ` Rajendra Nayak
2016-10-31 10:44 ` Jon Hunter
2016-11-02 8:56 ` Rajendra Nayak
2016-11-16 13:11 ` Ulf Hansson
2016-11-17 2:31 ` Rajendra Nayak
2016-11-17 15:39 ` Stanimir Varbanov
2016-11-22 13:05 ` Ulf Hansson
2016-11-23 3:48 ` Rajendra Nayak
2016-10-06 12:22 ` Ulf Hansson [this message]
2016-10-10 11:18 ` Jon Hunter
2016-10-10 14:04 ` Ulf Hansson
2016-10-11 9:15 ` Jon Hunter
2016-11-03 14:20 ` Jon Hunter
2016-11-16 10:48 ` Jon Hunter
2016-11-16 12:53 ` Rafael J. Wysocki
2016-11-22 11:12 ` Jon Hunter
2016-11-22 13:31 ` Ulf Hansson
2016-11-22 14:28 ` Jon Hunter
2016-11-22 18:26 ` Kevin Hilman
2016-11-22 18:41 ` Jon Hunter
2016-11-24 2:30 ` Stephen Boyd
2016-11-29 11:33 ` Marek Szyprowski
2016-12-15 11:38 ` Jon Hunter
2016-11-22 21:55 ` Rafael J. Wysocki
2016-11-23 9:29 ` Jon Hunter
2016-11-23 13:15 ` Rafael J. Wysocki
2017-02-28 15:18 ` Jon Hunter
2017-02-28 15:29 ` Geert Uytterhoeven
2017-03-13 9:37 ` Jon Hunter
2017-03-13 11:45 ` Ulf Hansson
2017-03-13 14:09 ` Jon Hunter
2017-03-13 14:19 ` Geert Uytterhoeven
2017-03-13 14:27 ` Jon Hunter
2017-03-13 14:38 ` Geert Uytterhoeven
2017-03-13 14:51 ` Jon Hunter
2017-03-13 14:42 ` Ulf Hansson
2017-03-15 8:57 ` Jon Hunter
2017-03-15 3:47 ` Nayak, Rajendra
2017-03-15 9:03 ` Jon Hunter
2017-03-01 6:19 ` Rajendra Nayak
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