From: Ian Campbell <Ian.Campbell@citrix.com>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Tim Deegan <tim@xen.org>,
Oleksandr Dmytryshyn <oleksandr.dmytryshyn@globallogic.com>,
Stefano.Stabellini@citrix.com, Jan Beulich <JBeulich@suse.com>,
xen-devel@lists.xen.org
Subject: Re: [RFC PATCH 11/13] cpufreq: add xen-cpufreq driver
Date: Fri, 10 Oct 2014 10:59:18 +0100 [thread overview]
Message-ID: <1412935158.27111.6.camel@citrix.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1410101052310.17038@kaball.uk.xensource.com>
On Fri, 2014-10-10 at 10:54 +0100, Stefano Stabellini wrote:
> On Fri, 10 Oct 2014, Jan Beulich wrote:
> > >> ACPI has obtained I2C resource handling a while ago,
> > >>
> Why is I2C needed for ACPI? I thought that all the freq changing ops
> would be hidden behind AML methods.
>From what Jan says it sounds to me like AML can now invoke i2c
operations...
> Honestly not knowing how much code is required to have I2C support in
> Xen, it is difficult for me to guess what would be the best approach.
> The GlobalLogic guys seem to think too much.
A simple i2c driver (without all the generic framework/bus
infrastructure which Linux has) is pretty simple.
I think the biggest complexity would come from i2c busses with both
cpufreq and other devices on them and managing the potentially shared
accesses.
Presumably ACPI systems must avoid having buses which are accessed both
via AML and by the OS directly. I expect DT has no such restriction.
Ian.
next prev parent reply other threads:[~2014-10-10 9:59 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-07 14:19 [RFC PATCH 00/13] xen_cpufreq implementation in Xen hypervisor Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 01/13] cpufreq: move cpufreq.h file to the xen/include/cpufreq location Oleksandr Dmytryshyn
2014-10-07 14:22 ` Andrew Cooper
2014-10-07 14:27 ` Oleksandr Dmytryshyn
2014-10-07 14:35 ` Jan Beulich
2014-10-09 6:04 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 02/13] pm: move processor_perf.h " Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 03/13] pmstat: move pmstat.c file to the xen/drivers/pm location Oleksandr Dmytryshyn
2014-10-07 14:38 ` Jan Beulich
2014-10-09 6:05 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 04/13] cpufreq: use turbo settings only for x86 architecture Oleksandr Dmytryshyn
2014-10-07 14:39 ` Jan Beulich
2014-10-09 6:05 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 05/13] pmstat: make pmstat functions more generalizable Oleksandr Dmytryshyn
2014-10-07 14:40 ` Jan Beulich
2014-10-09 6:06 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 06/13] cpufreq: make cpufreq driver " Oleksandr Dmytryshyn
2014-10-07 14:42 ` Jan Beulich
2014-10-09 6:06 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 07/13] xen/arm: enable cpu hotplug Oleksandr Dmytryshyn
2014-10-07 15:15 ` Julien Grall
2014-10-09 6:07 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 08/13] xen/dts: make the dt_find_property function to be global Oleksandr Dmytryshyn
2014-10-07 15:09 ` Julien Grall
2014-10-09 6:09 ` Oleksandr Dmytryshyn
2014-10-09 11:15 ` Julien Grall
2014-10-09 11:40 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 09/13] arch/arm: create device tree nodes for Dom0 cpufreq cpu driver Oleksandr Dmytryshyn
2014-10-07 15:26 ` Julien Grall
2014-10-09 6:10 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 10/13] xen: arm: implement platform hypercall Oleksandr Dmytryshyn
2014-10-07 15:39 ` Julien Grall
2014-10-09 6:11 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 11/13] cpufreq: add xen-cpufreq driver Oleksandr Dmytryshyn
2014-10-07 14:44 ` Jan Beulich
2014-10-08 13:51 ` Stefano Stabellini
2014-10-10 9:00 ` Jan Beulich
2014-10-10 9:04 ` Stefano Stabellini
2014-10-10 9:39 ` Jan Beulich
2014-10-10 9:39 ` Stefano Stabellini
2014-10-10 9:46 ` Jan Beulich
2014-10-10 9:54 ` Stefano Stabellini
2014-10-10 9:59 ` Ian Campbell [this message]
2014-10-10 12:51 ` Jan Beulich
2014-10-10 14:42 ` Stefano Stabellini
2014-10-13 8:56 ` Oleksandr Dmytryshyn
2014-10-13 9:39 ` Jan Beulich
2014-10-13 11:59 ` Oleksandr Dmytryshyn
2014-10-13 12:28 ` Jan Beulich
2014-10-13 13:38 ` Andrii Tseglytskyi
2014-10-13 14:11 ` Jan Beulich
2014-10-13 14:29 ` Andrii Tseglytskyi
2014-10-14 12:20 ` Jan Beulich
2014-10-14 12:39 ` Andrii Tseglytskyi
2014-10-14 12:51 ` Stefano Stabellini
2014-10-14 12:58 ` Andrii Tseglytskyi
2014-10-14 13:00 ` Andrii Tseglytskyi
2014-10-14 13:05 ` Ian Campbell
2014-10-14 13:07 ` Andrii Tseglytskyi
2014-10-15 10:55 ` Stefano Stabellini
2014-10-15 11:17 ` Andrii Tseglytskyi
2014-10-15 12:34 ` Ian Campbell
2014-10-15 16:26 ` Jan Beulich
2014-10-10 15:19 ` Ian Campbell
2014-10-10 10:40 ` Jan Beulich
2014-10-09 6:13 ` Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 12/13] xen: arm: implement XEN_SYSCTL_cpufreq_op Oleksandr Dmytryshyn
2014-10-07 14:19 ` [RFC PATCH 13/13] xen/arm: enable cpufreq functionality for ARM Oleksandr Dmytryshyn
2014-10-07 14:34 ` [RFC PATCH 00/13] xen_cpufreq implementation in Xen hypervisor Jan Beulich
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