From mboxrd@z Thu Jan  1 00:00:00 1970
From: marc.zyngier@arm.com (Marc Zyngier)
Date: Fri, 11 Apr 2014 10:43:30 +0100
Subject: [PATCH 3/4] arm: add basic support for Mediatek MT6589 boards
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To: linux-arm-kernel@lists.infradead.org
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On 11/04/14 10:11, Matthias Brugger wrote:
> 2014-04-10 11:01 GMT+02:00 Marc Zyngier <marc.zyngier@arm.com>:
>> A couple of things on top of Rob's comments:
>>
>> On Wed, Apr 09 2014 at 10:50:33 pm BST, Rob Herring <robherring2@gmail.com> wrote:
>>> On Wed, Apr 9, 2014 at 2:45 PM, Matthias Brugger <matthias.bgg@gmail.com> wrote:
>>>> This adds a generic devicetree board file and a dtsi for boards
>>>> based on the MT6589 SoCs from Mediatek.
>>>>
>>>> Apart from the generic parts (gic, clocks) the only component
>>>> currently supported are the timers.
>>>>
>>>> Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
>>
>> [...]
>>
>>>> diff --git a/arch/arm/mach-mediatek/Kconfig b/arch/arm/mach-mediatek/Kconfig
>>>> new file mode 100644
>>>> index 0000000..c0139ca
>>>> --- /dev/null
>>>> +++ b/arch/arm/mach-mediatek/Kconfig
>>>> @@ -0,0 +1,14 @@
>>>> +config ARCH_MEDIATEK
>>>> +       bool "Mediatek MT6589 SoC" if ARCH_MULTI_V7
>>>> +       select ARCH_REQUIRE_GPIOLIB
>>>
>>> Then where is your GPIO driver?
>>>
>>>> +       select ARM_GIC
>>>> +       select CACHE_L2X0
>>>> +       select HAVE_ARM_TWD if LOCAL_TIMERS
>>
>> Hell no! ;-) ARM_ARCH_TIMER is the way (please also add the missing
>> node).
> 
> I considered this, but the timer wasn't able to get it's clock frequency:
> "Architected timer frequency not available
> Division by zero in kernel."

This is because your bootloader/firmware is utterly broken, and doesn't
set CNTFRQ (it must be set on all CPUs, from secure mode). As a
*workaround*, you can set the timer frequency in the timer node, but
that's just a hack, and will prevent virtual machines from running on
such hardware.

	M.
-- 
Jazz is not dead. It just smells funny...