From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: dts: Update arch timer node with clock frequency
Date: Fri, 20 Sep 2013 09:17:16 +0100 [thread overview]
Message-ID: <523C048C.10303@arm.com> (raw)
In-Reply-To: <CAKuRcOLfRwJohWMhc=QMew87SXtBmkPUJwW7UzNry_gFuC-81Q@mail.gmail.com>
On 20/09/13 05:57, Yuvaraj Kumar wrote:
> Resending it as it bounced from kernel mailing group
>
> On Wed, Sep 18, 2013 at 3:53 PM, Mark Rutland <mark.rutland@arm.com> wrote:
>> [adding lakml]
>>
>> On Wed, Sep 18, 2013 at 11:11:53AM +0100, Yuvaraj Kumar C D wrote:
>>> Without the "clock-frequency" property in arch timer node, could able
>>> to see the below crash dump.
>>
>> Why does this cause the below crash specifically? What is CNTFRQ reading
>> as?
> Return value of arch_timer_get_cntfrq() is 0
>>
>> Your firmware or bootloader should set CNTFRQ -- setting the
>> clock-frequency is a work-around for buggy firmware/bootloaders that
>> should be avoided as far as possible.
> Why kernel should depend on bootloader/firmware to set CNTFRQ? Any
> specific reasons?
Because the kernel can't set it if running non-secure. Only secure mode
can do this (see the ARM ARM for details).
> Should'nt be indepenedent each other(kernel and bootloader/firmware)?
In my book, the firmware is responsible for setting up the platform in a
sane state. Leaving CNTFRQ in its UNKNOWN reset state is a bug, and your
firmware should program it on each CPU. Same goes for CNTVOFF, which
should be set to a common value (preferably zero).
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2013-09-20 8:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1379499113-20342-1-git-send-email-yuvaraj.cd@samsung.com>
2013-09-18 10:23 ` [PATCH] ARM: dts: Update arch timer node with clock frequency Mark Rutland
2013-09-20 4:57 ` Yuvaraj Kumar
2013-09-20 8:17 ` Marc Zyngier [this message]
2013-09-20 14:55 ` Christopher Covington
2013-09-20 15:04 ` Marc Zyngier
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