[U-Boot] [PATCH v6 00/15] Add PSCI support for Jetson TK1/Tegra124 + CNTFRQ fix

[Stephen Warren]

On 04/17/2015 12:47 AM, Jan Kiszka wrote:
> On 2015-04-14 16:30, Ian Campbell wrote:
>> On Tue, 2015-04-14 at 16:12 +0200, Jan Kiszka wrote:
>>> On 2015-04-14 16:06, Stephen Warren wrote:
>>>> On 04/14/2015 07:46 AM, Tom Rini wrote:
>>>>> On Mon, Apr 13, 2015 at 06:48:05AM +0200, Jan Kiszka wrote:
>>>>>
>>>>>> Changes in v6:
>>>>>>    - rebased over master
>>>>>>    - included Thierry's SMMU enabling patch
>>>>>>    - moved activation patch at the end so that it can be held back
>>>>>>
>>>>>> This version can also be found at
>>>>>> https://github.com/siemens/u-boot/tree/jetson-tk1-v6.
>>>>>
>>>>> So what level of coordination do we need on applying this series so that
>>>>> kernels (both old and new) can continue to function?  And perhaps README
>>>>> updates or similar?  Thanks!
>>>>
>>>> Hopefully this series doesn't change anything by default, and simply
>>>> allows people to turn on support for booting kernels in non-secure mode
>>>> if they want to? If so, there shouldn't be any co-ordination required.
>>>> If it changes the default behaviour, co-ordination is probably required,
>>>> and that'd be a bad thing.
>>>
>>> Sorry, forgot to mention: I can't flip the default behaviour to leave
>>> virtualization support off only for the TK1. That's a generic default.
>>
>> Would enabling it in the compile but adding "bootm_boot_mode=sec" to the
>> default environment (so it isn't used by default) be considered
>> sufficiently backwards compatible?
>
> This turned out to not work as expected: booting in secure mode seems
> to prevent that Linux can bring up CPUs 1-3. Not sure if this is to be
> expected or a bug, but I will now take a different route:

That was the whole point of the environment variable suggestion; the 
environment variable would default to off so nobody got new behaviour, 
but anyone who wanted to boot in secure mode could simply set the 
environment variable and get it. That way, nobody who doesn't want the 
feature needs to co-ordinate U-Boot and kernel updates. Why doesn't that 
work?

> diff --git a/arch/arm/cpu/armv7/Kconfig b/arch/arm/cpu/armv7/Kconfig
> index 61e7c82..e5d4dcc 100644
> --- a/arch/arm/cpu/armv7/Kconfig
> +++ b/arch/arm/cpu/armv7/Kconfig
> @@ -27,7 +27,7 @@ config ARMV7_BOOT_SEC_DEFAULT
>   config ARMV7_VIRT
>   	boolean "Enable support for hardware virtualization" if EXPERT
>   	depends on CPU_V7_HAS_VIRT && ARMV7_NONSEC
> -	default y
> +	default y if !TEGRA
>   	---help---
>   	Say Y here to boot in hypervisor (HYP) mode when booting non-secure.
>
>
> A patch to be inserted before the last one (and to be reverted once
> Linux is fixed) will follow.
>
> Jan
>