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

Ian Campbell ijc at hellion.org.uk
Fri Apr 17 16:04:36 CEST 2015


On Fri, 2015-04-17 at 07:57 -0600, Stephen Warren wrote:
> On 04/17/2015 12:47 AM, Jan Kiszka wrote:
> > On 2015-04-14 16:30, Ian Campbell wrote:
> >> 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?

Right, if this doesn't work then it is certainly a bug somewhere on the
u-boot side.

I fixed one such issue a while back ("ARM: bootm: do not add PSCI to fdt
when booting in secure mode.") but that's ancient history, but I know
that at that time it was working for me (I'm reasonably sure that was on
Tegra with my earlier PSCI patches)

Ian.





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