[U-Boot] [U-Boot, v2, 4/4] arm: am33xx: Add support for mulitiple PLL input frequencies

[Heiko Schocher <hs@denx.de>]

Hello Tom,

Am 09.06.2017 um 13:20 schrieb Tom Rini:
> On Fri, Jun 09, 2017 at 12:22:44PM +0200, Heiko Schocher wrote:
>> Hello Lokesh,
>>
>> Am 09.06.2017 um 11:25 schrieb Lokesh Vutla:
>>>
>>>
>>> On Friday 09 June 2017 09:30 AM, Heiko Schocher wrote:
>>>> Hello Tom,
>>>>
>>>> Am 09.06.2017 um 02:45 schrieb Tom Rini:
>>>>> On Thu, Jun 08, 2017 at 10:17:09AM +0530, Lokesh Vutla wrote:
>>>>>>
>>>>>>
>>>>>> On Thursday 08 June 2017 12:20 AM, Emmanuel Vadot wrote:
>>>>>>> On Fri, 12 May 2017 13:20:50 -0400
>>>>>>> Tom Rini <trini@konsulko.com> wrote:
>>>>>>>
>>>>>>>> On Fri, May 05, 2017 at 12:59:10PM +0530, Lokesh Vutla wrote:
>>>>>>>>
>>>>>>>>> am335x supports various sysclk frequencies which can be determined
>>>>>>>>> using sysboot pins. PLLs should be configures based on this
>>>>>>>>> sysclk frequency. Add PLL configurations for all supported
>>>>>>>>> frequencies.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>>>>>>>>> Reviewed-by: Tom Rini <trini@konsulko.com>
>>>>>>>>
>>>>>>>> Applied to u-boot/master, thanks!
>>>>>>>>
>>>>>>>> --
>>>>>>>> Tom
>>>>>>>
>>>>>>>    Hello,
>>>>>>>
>>>>>>>    This appears to break beaglebone black support, reverting this commit
>>>>>>> make u-boot works again.
>>>>>>
>>>>>> hmm..I see the problem. Here we are hard coding MPU freq to 1GHz even
>>>>>> efuse say it is not supported(I am not sure why this is being done, may
>>>>>> be Tom can give more details). Even in kernel I see that cpufreq is
>>>>>> reading efuse to determine mpu frequency. Now that we have jitter
>>>>>> optimized pll configurations, looks like unsupported freq is causing an
>>>>>> issue. Can you see if the below patch helps?
>>>>>
>>>>> Well, in the kernel, did anyone poke the Beagleboard folks about this,
>>>>> before pushing the change?  There's BBB shipping with chips that did not
>>>>> have their efuses set, hence the way things were structured in U-Boot.
>>>>
>>>> I have runnint tbot tests on a BBB [1] ... and yes, currently test
>>>> is red = bad ... :-(
>>>>
>>>> Not sure, if it is this patch ...
>>>
>>> Yeah, I don't think this is the patch causing the issue. AM335x-evm
>>> boots fine for me. There are similar boot failures reported[1] on NVIDIA
>>> platforms as well. Not sure if we are hitting the same issue. Ill did
>>> more into this and update you guys.
>>>
>>> [1] https://www.mail-archive.com/u-boot at lists.denx.de/msg252698.html
>>
>> Time for using tbot and automated git bisect testcase ;-)
>
> How do you have the BBB configured such that you can recover it from a
> bad U-Boot, automatically?  Thanks!

That;s exactly the reason, why I did not started a "git bisect", as this
is not solved for the BBB in our lab. Wolfgang bought such a Airflash
card, but we did not found time to try it.

bye,
Heiko
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