From: kesavan.abhilash@gmail.com (Abhilash Kesavan)
To: linux-arm-kernel@lists.infradead.org
Subject: Problems booting exynos5420 with >1 CPU
Date: Fri, 6 Jun 2014 23:42:13 +0530 [thread overview]
Message-ID: <CAM4voakAMN4jdAZDPz55tnc3woZDieZ5aL3TVU2kYsNHT+AMqg@mail.gmail.com> (raw)
In-Reply-To: <CAD=FV=Vo1JR6n496Q3FqXjRBkbTBRg89_fJQNsqeRx8WQW_a9w@mail.gmail.com>
Hi Doug,
On Fri, Jun 6, 2014 at 11:32 PM, Doug Anderson <dianders@google.com> wrote:
> Abhilash,
>
> On Fri, Jun 6, 2014 at 10:36 AM, Abhilash Kesavan
> <kesavan.abhilash@gmail.com> wrote:
>> Hi Doug,
>>
>> The first change in the kernel (clearing an iRAM location) is needed
>> because of an unnecessary change that we are carrying in the Chrome
>> U-boot. There is no reason for us to have the workaround in the
>> mainline kernel. Rather, we should remove the check from our u-boot.
>> However AFAIR a clean-up patch that I had posted internally was not
>> accepted as we had frozen the SPL at the time.
>
> Ah, is that this one, or a different one?
>
> https://chromium-review.googlesource.com/#/c/66049/
Yes, this along with a kernel side change.
>
>
> If we land that patch now it won't help since nobody is going to be
> updating their read-only firmware. We'll need to put code somewhere
> that fixes it.
We just carry the workaround fix locally until we migrate to mainline
u-boot for 5420 where the unnecessay check will not be present.
>
>
>> The second change is to enable snoops for boot cluster. Internally, we
>> were disabling the snoops for both the clusters at power off and
>> enabling it in power_up_setup and power_up. However, I dropped the
>> approach due to problems pointed out by Nicolas here
>> http://www.spinics.net/lists/arm-kernel/msg324091.html related to
>> cpuidle. Hence, we turn it on at the u-boot.
>
> I think I followed all that. What you're saying is that our kernel
> dynamically enables and disables snoops as needed, but Nicolas pointed
> out that it was unsafe (though apparently we're not seeing problems in
> our usage).
We did not see any problems as CPUIdle was one of the problematic
scenarios which we have not got enabled.
>
> ...so now the kernel doesn't touch the snoops and assumes that U-Boot
> turned them on.
The kernel does turn on the snoops for the incoming cluster.
>
>
> Ugh.
Regards,
Abhilash
>
> -Doug
next prev parent reply other threads:[~2014-06-06 18:12 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-06 1:08 Problems booting exynos5420 with >1 CPU Doug Anderson
2014-06-06 4:38 ` Tushar Behera
2014-06-06 17:17 ` Doug Anderson
2014-06-06 17:36 ` Abhilash Kesavan
2014-06-06 18:02 ` Doug Anderson
2014-06-06 18:12 ` Abhilash Kesavan [this message]
2014-06-06 18:20 ` Doug Anderson
2014-06-06 18:31 ` Abhilash Kesavan
2014-06-06 18:56 ` Doug Anderson
2014-06-06 19:09 ` Abhilash Kesavan
2014-06-06 19:12 ` Abhilash Kesavan
2014-06-06 20:49 ` Doug Anderson
2014-06-06 21:01 ` Russell King - ARM Linux
2014-06-06 21:12 ` Doug Anderson
2014-06-06 21:44 ` Doug Anderson
2014-06-06 20:37 ` Olof Johansson
2014-06-06 20:46 ` Abhilash Kesavan
2014-06-06 21:01 ` Olof Johansson
2014-06-06 21:06 ` Abhilash Kesavan
2014-06-06 21:34 ` Nicolas Pitre
2014-06-06 21:49 ` Olof Johansson
2014-06-06 21:59 ` Doug Anderson
2014-06-06 22:38 ` Nicolas Pitre
2014-06-06 23:03 ` Doug Anderson
2014-06-06 22:17 ` Nicolas Pitre
2014-06-06 21:48 ` Nicolas Pitre
2014-06-07 3:25 ` Abhilash Kesavan
2014-06-07 16:10 ` Nicolas Pitre
2014-06-07 17:56 ` Lorenzo Pieralisi
2014-06-07 20:06 ` Nicolas Pitre
2014-06-07 22:36 ` Lorenzo Pieralisi
2014-06-07 23:53 ` Olof Johansson
2014-06-08 0:19 ` Russell King - ARM Linux
2014-06-08 2:52 ` Olof Johansson
2014-06-08 18:26 ` Nicolas Pitre
2014-06-08 18:29 ` Russell King - ARM Linux
2014-06-08 18:55 ` Nicolas Pitre
2014-06-08 19:02 ` Russell King - ARM Linux
2014-06-08 12:45 ` Lorenzo Pieralisi
2014-06-08 14:34 ` Russell King - ARM Linux
2014-06-08 17:53 ` Nicolas Pitre
2014-06-09 20:47 ` Kevin Hilman
2014-06-09 22:26 ` Lorenzo Pieralisi
2014-06-10 4:25 ` Nicolas Pitre
2014-06-10 9:19 ` Lorenzo Pieralisi
2014-06-10 14:14 ` Catalin Marinas
2014-06-10 16:49 ` Nicolas Pitre
2014-06-10 17:42 ` Catalin Marinas
2014-06-10 19:15 ` Nicolas Pitre
2014-06-09 20:27 ` Kevin Hilman
2014-06-09 20:35 ` Doug Anderson
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