[fedora-arm] Re: Dragonboard 410c?

Christopher,

Thank you

I may print this off and bring it to the meeting to highlight the
challenges some of these boards present.

Robert

On 01/20/2017 12:06 PM, Christopher Covington wrote:
> Hi Robert,
>
> On 01/18/2017 09:02 PM, Robert Moskowitz wrote:
>> There is a local (Detroit) IoT meeting showcasing the Dragonboard 410c.
>>
>> What is the status of support on it now?
>>
>> Want to know to what degree I try to go to the meeting...
> It looks like the Dragonboard 410c has an APQ8016 chip, which is basically
> the MSM8916 with no modem, so broadly equivalent to applications processor
> software.
>
> There has been a lot of work to get those and other Qualcomm Technologies
> chips supported in the upstream Linux kernel, but some of it has only
> been finished recently, for example with display support for 8016 landing
> in 4.9:
>
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bd3af15a4e4d528bb0a0eea1daca0b818baa9fd8
>
> A quick look at Fedora kernel configuration options makes me worried that
> the Fedora 25 kernel would not work on the DB410c out of the box.
>
> # CONFIG_MSM_GCC_8916 is not set
> http://pkgs.fedoraproject.org/cgit/rpms/kernel.git/tree/baseconfig/arm/arm64/CONFIG_MSM_GCC_8916
>
> GCC is the Global Clock Controller in this context. I have no idea how
> it works. It sounds important, but perhaps it's only required for
> run-time changes to the clocks, which may or may not be needed for basic
> functionality. Basic functionality may be available by coasting along on
> the clock setup from firmware. If somebody like Stephen or Andy who knows
> this stuff wants to tell me what to change in the configuration I'd be
> happy to prepare the patch, although I only have 8074 and 8064 boards
> and not 8016 myself for testing.
>
> One of the barriers to distribution support of these Q mobile devices has
> been the firmware/bootloader. The devices come with Little Kernel (LK) as
> the primary bootloader. I've heard that it requires special lines in the
> device tree file, but since these aren't useful to Linux, they aren't
> allowed to be kept in the device tree source on kernel.org. So if you want
> to use upstream device tree files, you need to run a tool to insert the
> special bootloader-specific lines before or while creating the device tree
> blob.
>
> https://source.codeaurora.org/quic/la/device/qcom/common/tree/dtbtool/dtbtool.txt?h=l_master
> https://source.codeaurora.org/quic/kernel/skales/tree/dtbTool
>
> Once that's complete, the kernel, device-tree-with-bootloader-extras, and
> initramfs must be packaged into the Android fastboot/bootimg binary image
> format:
>
> https://android.googlesource.com/platform/system/core/+/master/mkbootimg/bootimg.h#66
> https://source.codeaurora.org/quic/kernel/skales/tree/mkbootimg
>
> Fedora doesn't support this format at the moment, and I think some or most
> developers favor putting a familiar bootloader in the bootimg as a
> compatibility shim. As far as I know, that's yet another unfinished project.
>
> If anyone knows better, please correct me if I got any of this wrong, but
> hopefully this is a useful starting point.
>
> Regards,
> Cov
>
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