[RFC][TRUSTY] X-Gene platform support

[Dann Frazier]

On Thu, Mar 13, 2014 at 8:22 AM, Tim Gardner <tim.gardner at canonical.com> wrote:
> On 03/11/2014 12:15 PM, Dann Frazier wrote:
>>
>> Hi,
>>   I've assembled a git tree with support for the X-Gene platform:
>>
>> git://kernel.ubuntu.com/dannf/trusty-xgene.git for-ubuntu-20140310
>>
>> The PCI changes in the above are fairly significant and still under
>> upstream review. I've therefore provided a separate branch with these
>> changes backed out and replaced with an earlier version of the host
>> controller driver, with fewer dependencies:
>>
>> git://kernel.ubuntu.com/dannf/trusty-xgene.git for-ubuntu-20140310-oldpci
>>
>
> Ugh! Even with the PCI reverts there are some questionable patches wrt to
> maintenance and stability.

Though, other than SATA and PCI, I think the drivers are pretty well
self-contained,
so hopefully are low risk for other platforms. And we're certainly
down for tracking
upstream progress and updating them over time.

> I could _probably_ accept the ahci_platform patches since they are already
> in linux-next and will likely make it into 3.15 (though I'll remind you that
> I _really_ like to just cherry-pick the final patch from Linus' repo). Are
> the "Library-ise" patches necessary ?
>
> My knee jerk reaction is a NAK to all of the KVM patches. They appear to be
> a work in progress and likely won't even make the 3.15 merge window.
>
> Likewise with "arm64: PCI(e) arch support". A work in progress that is
> unlikely to make 3.15.
>
> Instead of removing the X-Gene reboot driver, can't we just disable the
> config ? Its a bit less churn and we won't have to resolve the conflict in
> future kernels.

Seems like that should work, but it didn't in my testing - system hangs on reset
even though:
  # CONFIG_POWER_RESET_XGENE is not set
  CONFIG_POWER_RESET_SYSCON=y
I'll investigate why, but probably not until Monday.

> What is the current state of the X-gene SOC ? I see that we already have DTB
> files for mustang and storm. Do they already boot and have networking ?

With the current Ubuntu kernel, they can boot, but not into userspace
(no disk, no networking).

fyi, I've updated my branch:

git://kernel.ubuntu.com/dannf/trusty-xgene.git for-ubuntu-20140314

This pulls in the KVM changes from linux-next (I assume its no
different than what
you have), and also updates to the latest submitted version of the SATA driver.

There's a few other experiments in it - no longer reverting the
RESET_XGENE driver
(as mentioned above), and making QMTM & NET_XGENE both modules. Neither
seems to be working well. I'll investigate further next week and post
a new tree, and
also include the latest submitted PCI patches.

  -dann

> rtg
> --
> Tim Gardner tim.gardner at canonical.com