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

[Stephen Warren]

On 04/17/2015 08:02 AM, Jan Kiszka wrote:
> On 2015-04-17 15:57, Stephen Warren wrote:
>> 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?
>
> Because it breaks SMP on Linux, namely the boot of secondary cores.
> Don't ask me why, I didn't debug the details. But you can probably
> reproduce by specifying bootm_boot_mode=sec with current U-boot and
> recent upstream kernels.

I suspect the environment variable isn't working, and Linux is still 
being booted in non-secure mode. That would be a bug in U-Boot.