Re: [PATCH] ARM: dts: Remove mau_pd node for Exynos5420

[Tushar Behera <tushar.behera@linaro.org>]

On 04/23/2014 03:43 PM, Kukjin Kim wrote:
> Tushar Behera wrote:
>>
>> On 22 April 2014 13:08, Alim Akhtar <alim.akhtar@gmail.com> wrote:
>>> Hi Tushar
>>>
>>> On Tue, Apr 22, 2014 at 11:09 AM, Tushar Behera
>>> <tushar.behera@linaro.org> wrote:
>>>> MAU powerdomain provides clocks for Audio sub-system block. This block
>>>> comprises of the I2S audio controller, audio DMA blocks and Audio
>>>> sub-system clock registers.
>>>>
>>>> Right now, there is no way to hook up power-domains with clock
>> providers.
>>>> During late boot when this power-domain gets disabled, we get following
>>>> external abort.
> 
> + Jonghwan Choi
> 
> Well, this is not a perfect solution to support MAU power domain, it's true it is a problem right now though.
> 
> In other words, this is just temporal fix for the problem.
> 
> How about accessing clock stuff for audio sub-system with handling MAU power domain via generic IO power domain?
> 

+ Tomasz Figa

Existing power domain driver exynos4_pm_init_power_domain is registered
with an arch_initcall whereas the clk-exynos-audss driver is registered
with core_initcall. Hence even if add mau_pd node to clk-exynos-audss
node, the binding with power-domain doesn't happen.

Alternately, if Tomasz's patches are applied [1], power-domain binding
is successful. But because of the init order, clk-exynos-audss defers
probe resulting in a kernel crash. Forcing clk-exynos-audss to register
through arch_initcall() fixes this issue, but I am not sure if that is okay.

[1] http://www.spinics.net/lists/kernel/msg1728566.html

>>> ?? which abort?? Can you please mention it here?
>>>>
>>
>> Thanks Alim for spotting this ... I somehow missed adding this.
>>
>> <<<<
>> Unhandled fault: imprecise external abort (0x1406) at 0x00000000
>> Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000007
>>>>>>
>>
>> Kukjin,
>>
>> Let me know if I need to resend the patch.
> 
> - Kukjin
> 


-- 
Tushar Behera