[U-Boot] Question regarding cpu_get_count(..)

Christian Gmeiner christian.gmeiner at gmail.com
Mon Apr 9 07:52:19 UTC 2018


Hi Bin

2018-04-06 10:30 GMT+02:00 Christian Gmeiner <christian.gmeiner at gmail.com>:
> Hi Bin
>
> 2018-04-06 9:47 GMT+02:00 Bin Meng <bmeng.cn at gmail.com>:
>> Hi Christian,
>>
>> On Fri, Apr 6, 2018 at 2:55 PM, Christian Gmeiner
>> <christian.gmeiner at gmail.com> wrote:
>>> Hi
>>>
>>> I tried my luck on the u-boot irc channel but nobody cared so I am
>>> asking this here again.
>>> Does cpu_get_count(..) return the number of physical CPUs or the
>>> number of logical CPUs?
>>>
>>> I am currently preparing a patch set which adds
>>> arch/x86/cpu/queensbay/cpu.c and there I need
>>> to specify a struct cpu_ops with a function called get_count(). But
>>> what must I return (physical vs. logical CPU count)?
>>>
>>
>> It's logical CPUs, say you have one physical CPU, each with
>> dual-threads, so get_count() returns 2.
>>
>
> Good to know. I am looking into an issue where vxworks 7 intel gen is not able
> to detect the correct amount of physical and logical CPUs (on a blob UEFI-Bios).
> I compared the new platform with an older queensbay based one the there are some
> discrepancies. As vx7 makes use of a handful of BIOS tables I thought I start at
> the root (get_count()) and move up. So as a result of this that means that the
> MP table has one "Processor Entry" per logical CPU - or? I tired to get that
> information for the spec but failed.
>
>> But Intel CrownBay already supports SMP in U-Boot. What patch are you
>> working on?
>
> I am out of office today and do not have access to my wip git rep :(
> But I needed
> to set some speed frequency registers.. but can tell you more on Monday.
>

Okay.. yeah I need to configure speed: https://hastebin.com/toqihobali.cpp

So the end result is to get all BIOS tables standard conform and vx7 should
be happy - I hope.

-- 
greets
--
Christian Gmeiner, MSc

https://christian-gmeiner.info


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