From: Julien Grall <julien.grall@arm.com>
To: Stefano Stabellini <sstabellini@kernel.org>,
Dirk Behme <dirk.behme@de.bosch.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@codeaurora.org>,
xen-devel@lists.xenproject.org, linux-clk@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] xen/arm: register clocks used by the hypervisor
Date: Tue, 5 Jul 2016 15:02:19 +0100 [thread overview]
Message-ID: <577BBDEB.7000305__38143.4976043694$1467727421$gmane$org@arm.com> (raw)
In-Reply-To: <577BBC1A.8020209@arm.com>
On 05/07/16 14:54, Julien Grall wrote:
>
>
> On 05/07/16 14:53, Stefano Stabellini wrote:
>> On Thu, 30 Jun 2016, Dirk Behme wrote:
>>> +- clocks: one or more clocks to be registered.
>>> + Xen hypervisor drivers might replace native drivers, resulting in
>>> + clocks not registered by these native drivers. To avoid that these
>>> + unregistered clocks are disabled, then, e.g. by clk_disable_unused(),
>>> + register them in the hypervisor node.
>>> + An example for this are the clocks of the serial driver. If the
>>> clocks
>>> + used by the serial hardware interface are not registered by the
>>> serial
>>> + driver the serial output might stop once clk_disable_unused() is
>>> called.
>>
>> What if we use the "status" property of the clocks? Could we set it to
>> "disabled" in Xen? Would that be enough for Linux to leave them alone?
>
> clocks could be shared between multiple devices. So it is not possible
> to disable the clock.
To give an example, below the UART node for juno
(arch/arm64/boot/dts/arm/juno-base.dtsi):
soc_uart0: uart@7ff80000 {
compatible = "arm,pl011", "arm,primecell";
reg = <0x0 0x7ff80000 0x0 0x1000>;
interrupts = <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&soc_uartclk>, <&soc_refclk100mhz>;
clock-names = "uartclk", "apb_pclk";
};
The clock soc_refclk100mhz is shared with the mailbox.
Regards,
--
Julien Grall
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Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-07-05 14:02 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1467282752-14053-1-git-send-email-dirk.behme@de.bosch.com>
2016-06-30 14:21 ` [PATCH v2] xen/arm: register clocks used by the hypervisor Mark Rutland
[not found] ` <20160630142136.GE20363@leverpostej>
2016-06-30 14:56 ` Dirk Behme
[not found] ` <57753328.9060300@gmail.com>
2016-06-30 15:18 ` Mark Rutland
2016-06-30 15:33 ` Julien Grall
2016-07-05 13:53 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.10.1607051449370.2575@sstabellini-ThinkPad-X260>
2016-07-05 13:54 ` Julien Grall
[not found] ` <577BBC1A.8020209@arm.com>
2016-07-05 14:02 ` Julien Grall [this message]
2016-07-05 14:04 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.10.1607051456410.2575@sstabellini-ThinkPad-X260>
2016-07-05 14:08 ` Julien Grall
[not found] ` <577BBF69.8010809@arm.com>
2016-07-05 14:37 ` Stefano Stabellini
2016-07-06 1:34 ` Michael Turquette
[not found] ` <146776885213.35356.11565744417822933094@resonance>
2016-07-06 13:10 ` Julien Grall
[not found] ` <577D035C.7090504@arm.com>
2016-07-06 13:16 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.10.1607061412370.26575@sstabellini-ThinkPad-X260>
2016-07-06 13:26 ` Julien Grall
2016-07-06 13:48 ` Mark Rutland
2016-07-06 20:42 ` Michael Turquette
[not found] ` <146783774807.35356.6362595927321996311@resonance>
2016-07-07 7:32 ` Dirk Behme
[not found] ` <dad950db-4c02-e5a2-0ce9-682a40cd12d7@de.bosch.com>
2016-07-08 2:50 ` Michael Turquette
[not found] ` <146794625655.73491.13497001485518368066@resonance>
2016-07-08 5:51 ` Dirk Behme
[not found] ` <373bf006-1a5e-0b2b-278d-d5ec0d8737fd@de.bosch.com>
2016-07-08 9:21 ` Julien Grall
2016-07-08 6:48 ` Dirk Behme
[not found] ` <20733b68-9529-bdb9-2a7d-576c8193f15c@de.bosch.com>
2016-07-08 9:35 ` Julien Grall
[not found] <1467701423-31138-1-git-send-email-dirk.behme@de.bosch.com>
2016-07-05 10:39 ` Mark Rutland
[not found] ` <20160705103917.GC20478@leverpostej>
2016-07-05 10:45 ` Dirk Behme
[not found] ` <b2431af6-f415-41db-5651-8cb8d3b08822@de.bosch.com>
2016-07-05 11:07 ` Mark Rutland
[not found] ` <20160705110736.GD20478@leverpostej>
2016-07-06 23:38 ` Michael Turquette
2016-07-05 6:50 Dirk Behme
-- strict thread matches above, loose matches on Subject: below --
2016-06-30 10:32 Dirk Behme
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