[U-Boot] [PATCH 1/3] ARM: rmobile: Switch CPU to non-secure HYP mode for r8a7790 based boards

[Oleksandr]

On 09.02.19 18:35, Marek Vasut wrote:

Hi

> On 2/7/19 6:19 PM, Oleksandr wrote:
>
> [...]
>
>>>>>> +        /* Update registers with correct frequency */
>>>>>> +        writel(freq, TIMER_BASE + TIMER_CNTFID0);
>>>>>> +        asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
>>>>>> +
>>>>>> +        /* Make sure arch timer is started by setting bit 0 of
>>>>>> CNTCR */
>>>>>> +        writel(1, TIMER_BASE + TIMER_CNTCR);
>>>>> Shouldn't this be in the timer driver instead ?
>>>> Which timer driver? Probably, I missed something, but I didn't find any
>>>> arch timer driver being used for Gen2.
>>>>
>>>> I see that TMU timer (arch/sh/lib/time.c) is used as a system timer, but
>>>> it is yet another IP.
>>>>
>>>> Would it be correct, if I move arch timer updating code to
>>>> arch/arm/mach-rmobile directory?
>>>>
>>>> Actually, at the same location the corresponding code lives in Linux:
>>>>
>>>> https://elixir.bootlin.com/linux/v5.0-rc5/source/arch/arm/mach-shmobile/setup-rcar-gen2.c#L61
>>>>
>>> Presumably if this is something else than TMU, it needs proper driver
>>> that goes into drivers/ .
>> Did I get your point correctly that new driver (specially for Gen2 arch
>> timer) should be introduced in U-Boot and
>>
>> the only one thing it is intended to do is to configure that timer for
>> the future use by Linux/Hypervisor?
>>
>> If yes, the only question I have is how that new driver is going to be
>> populated? There is no corresponding node for arch timer in the device
>> tree.
>>
>> https://elixir.bootlin.com/linux/v5.0-rc5/source/arch/arm/boot/dts/r8a7790.dtsi
>>
>>
>> So, do I need specially for this case add arch timer node with reg and
>> compatible properties?
>>
>> Sorry if I ask obvious questions, not familiar enough with U-Boot.
> You would need a DT entry and a bit of code to start the timer in case
> the PSCI is enabled, yes. This would then fit into the DM/DT paradigm.

I understand your point, thank you.

Will create a simple driver for arch timer in V2.


>
>>>>>> +    }
>>>>>> +}
>>>>>> +
>>>>>> +/*
>>>>>> + * In order not to break compilation if someone decides to build
>>>>>> with PSCI
>>>>>> + * support disabled, keep these dummy functions.
>>>>>> + */
>>>>> That's currently the only use-case.
>>>> Shall I drop this comment and dummy functions below?
>>> Since there is no PSCI support, yes.
>> Understand.
>>
>>> [...]
>>>
>>> I'd like to have a cover letter go with V2, which describes what you're
>>> trying to achieve here.
>> Yes, sure. Cover letter is present for the current V1 as well.
>>
>> I thought that I had CC-ed all.
>>
>> This is a link to it:
>>
>> http://u-boot.10912.n7.nabble.com/PATCH-0-3-PSCI-support-for-r8a7790-SoC-Lager-Stout-boards-td357352.html
> Thanks
>