[RFC][TRUSTY] X-Gene platform support

[Dann Frazier]

On Fri, Mar 14, 2014 at 1:12 PM, Dann Frazier
<dann.frazier at canonical.com> wrote:
> 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.

Whups, I was apparently testing with the wrong .dtb. I've verified
that it *is* safe to keep
xgene_qmtm and xgene_enet as modules, so I recommend:

CONFIG_AHCI_XGENE=m
CONFIG_NET_XGENE=m
CONFIG_PCI_XGENE=y
CONFIG_PHY_XGENE=y
CONFIG_RTC_DRV_XGENE=y
CONFIG_XGENE_QMTM=m

Also, it is safe to disable CONFIG_POWER_RESET_XGENE and keep the
driver in place.

Sorry for the confusion.