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
_______________________________________________
arm mailing list -- arm@xxxxxxxxxxxxxxxxxxxxxxx
To unsubscribe send an email to arm-leave@xxxxxxxxxxxxxxxxxxxxxxx
