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

[Robert Nelson]

On Wed, Jun 7, 2017 at 11:47 PM, Lokesh Vutla <lokeshvutla at ti.com> wrote:
>
>
> On Thursday 08 June 2017 12:20 AM, Emmanuel Vadot wrote:
>> On Fri, 12 May 2017 13:20:50 -0400
>> Tom Rini <trini at 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 at ti.com>
>>>> Reviewed-by: Tom Rini <trini at 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?

In the kernel, we are re-enabling the 1GHz option in the BoneBlack's
device tree blob:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/arm/boot/dts/am335x-boneblack.dts?h=v4.12-rc4&id=bc4b1736f246102e84ce6d3f1a32f614ae27d81f

Regards,

-- 
Robert Nelson
https://rcn-ee.com/