[GIT PULL] Broadcom Cygnus SoC defconfig changes

Scott Branden sbranden at broadcom.com
Sat Nov 8 21:45:18 PST 2014

Hi Olof,

Thanks for the comments.  Please see my questions inline before we 
determine what needs to be done for the defconfig patchset.

On 14-11-08 04:13 PM, Olof Johansson wrote:
> On Thu, Oct 30, 2014 at 12:50:09PM -0700, Florian Fainelli wrote:
>> The following changes since commit f114040e3ea6e07372334ade75d1ee0775c355e1:
>>    Linux 3.18-rc1 (2014-10-19 18:08:38 -0700)
>> are available in the git repository at:
>>    http://github.com/brcm/linux.git tags/arm-soc/for-3.18/cygnus-defconfig-v9
>> for you to fetch changes up to aa0204801143ee2d47e9e8dd5f39cdddd5613b4b:
>>    ARM: multi_v7_defconfig: Enable Broadcom Cygnus (2014-10-30 11:01:35 -0700)
> Hi Florian,
> Apologies for the delay in dealing with this pull request.
>> ----------------------------------------------------------------
>> This patchset contains initial support for Broadcom's Cygnus SoC based on our
>> iProc architecture. Initial support is minimal and includes just the mach
>> platform code, clock driver, and a basic device tree configuration. Peripheral
>> drivers will be submitted soon, as will device tree configurations for other
>> Cygnus board variants.
>> These are the defconfig parts of the changes
>> ----------------------------------------------------------------
>> Jonathan Richardson (1):
>>        ARM: cygnus defconfig : Initial defconfig for Broadcom Cygnus SoC
>> Ray Jui (1):
>>        ARM: multi_v7_defconfig: Enable Broadcom Cygnus
>> Scott Branden (1):
>>        ARM: bcm_defconfig/multi_v7_defconfig: remove one level of menu from Kconfig
>>   arch/arm/configs/bcm_cygnus_defconfig | 237 ++++++++++++++++++++++++++++++++++
>>   arch/arm/configs/bcm_defconfig        |   3 +-
>>   arch/arm/configs/multi_v7_defconfig   |  21 ++-
> Please send multi_v7_defconfig updates as a patch instead of including in
> a merge request. We ask for this because it's a file that many maintainers
> touch and it's easy that we get lots of conflicts otherwise.
OK, easy to do.  Are there other files that we need to be aware of that 
have these different requirements to merge as well?

> As far as the bcm_cygnus_defconfig: Since new platforms are multiplatform
> enabled by default, we normally only prefer to have one defconfig per vendor.
> We've made exceptions in cases where the families are very different, but in
> general one defconfig per vendor should be sufficient.
> I.e. please enable the cygnus options in bcm_defconfig instead of adding a new
> one.

Hi Olof, we can do this.  But this makes bcm_defconfig unusable for us 
in a product and is not a simple configuration to start from for our 
customers.  bcm_defconfig is a different SoC family based around the 
Kona architecture. bcm_defconfig won't be what we build and test on 
Cygnus at all.  There is a script in scripts/kconfig/mergeconfig.pl that 
allows you to merge config files together if you wish to have a kernel 
support multiple SoCs.  I see the same problem with multi_v7_defconfig 
but even worse.  It isn't a configuration we will ever use.  Its only 
purpose seems to be to enable our drivers in the that build just in case 
somebody else happens to break something in the build.

As it stands, multi_v7_defconfig boots noticably slower than 
bcm_cygnus_defconfig.  And, the kernel is larger than we want.  And, the 
kconfigs are more complicated than we need for our boards.  I also 
notice some of the other SoCs families enabled automatically turn on a 
lot of features we don't want on.

Perhaps most of the multi_v7_defconfig merge issue you are facing could 
be solved if you used the mergconfig.pl script to merge multiple 
defconfigs together?

What we wish to do is have a config file that only supports the Cygnus 
family of SoCs.  This allows others to easily see what applies to Cygnus 
without being confused by other configurations.  And, if somebody wishes 
to use scripts/kconfig/mergeconfig.pl to merge different SoC support 
together they are free to do so.

So, we can do as you ask to get this upstreamed.  But it really serves 
little purpose for us other than verifying things build.

Where do we upstream the defconfig that we actually use?  Or is this 
just not done and everyone keeps everything locally and has to continue 
to maintain it there?

> -Olof

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