[U-Boot] [PATCH] ARM: tegra: only enable SCU on Tegra20

Tom Warren TWarren at nvidia.com
Tue Jun 4 22:33:21 CEST 2013

Sorry, my BW is being used up by internal projects. I'll pull it down, apply/build/test in u-boot-tegra/next, and then I can send a PR to Albert if you think it needs to move higher up right away.


> -----Original Message-----
> From: Stephen Warren [mailto:swarren at wwwdotorg.org]
> Sent: Tuesday, June 04, 2013 12:34 PM
> To: Tom Warren
> Cc: u-boot at lists.denx.de; Simon Glass; Stephen Warren
> Subject: Re: [U-Boot] [PATCH] ARM: tegra: only enable SCU on Tegra20
> On 05/23/2013 04:26 PM, Stephen Warren wrote:
> > From: Tom Warren <twarren at nvidia.com>
> >
> > The non-SPL build of U-Boot on Tegra only runs on a single CPU, and
> > hence there is no need to enable the SCU when running U-Boot. If an
> > SMP OS is booted, and it needs the SCU enabled, it will enable the SCU
> > itself. U-Boot doing so is redundant.
> >
> > The one exception is Tegra20, where an enabled SCU is required for
> > some aspects of PCIe to work correctly.
> >
> > Some Tegra SoCs contain CPUs without a software-controlled SCU. In
> > this case, attempting to turn it on actively causes problems. This is
> > the case for Tegra114. For example, when running Linux, the first (or
> > at least some very early) user-space process will trigger the
> > following kernel
> > message:
> >
> > Unhandled fault: imprecise external abort (0x406) at 0x00000000
> >
> > This is typically accompanied by that process receving a fatal signal,
> > and exiting. Since this process is usually pid 1, this causes total
> > system boot failure.
> Tom, is this patch OK? It's a rather critical bug-fix for Tegra114, so I'd like to
> make sure it gets into the upcoming release. Thanks.
This email message is for the sole use of the intended recipient(s) and may contain
confidential information.  Any unauthorized review, use, disclosure or distribution
is prohibited.  If you are not the intended recipient, please contact the sender by
reply email and destroy all copies of the original message.

More information about the U-Boot mailing list