[U-Boot] And what about fitImages and ram disks?

Patrick Doyle wpdster at gmail.com
Mon Jun 17 14:59:02 UTC 2019

On Mon, Jun 17, 2019 at 10:22 AM Daniel Schwierzeck
<daniel.schwierzeck at gmail.com> wrote:
> Am Mo., 17. Juni 2019 um 15:40 Uhr schrieb Patrick Doyle <wpdster at gmail.com>:
> > On Mon, Jun 17, 2019 at 7:27 AM Daniel Schwierzeck
> > <daniel.schwierzeck at gmail.com> wrote:
> > > Am Fr., 14. Juni 2019 um 23:05 Uhr schrieb Patrick Doyle <wpdster at gmail.com>:
> I guess you overlooked my first comment? :D
> The double relocation has been fixed after v2019.04 with
> e5151666364e64e6ca6e554e3d53f2a53fbc1800.
Oops, yes I did.  I am sorry for the noise.

> Could you also share how do you deploy your device-tree blob? Do you put
> it in the FIT image and use DTB hand-over to Linux or do you use the
> built-in or appended DTB approach? Patch
> 6943cc9732202b9c65990cff9f74cea6b8173e09
> is only relevant for the DTB hand-over case where the initramfs adress and size
> will be embedded in the DTB. Otherwise the address and size is passed
> via kernel command line. This should work without problems.
I am working with a kernel that was massaged from an OpenWRT release
into a Yocto build environment.  The person who created the Yocto
recipe for the kernel adapted the approach used in OpenWRT where, with
the help of OpenWRT specific patches, the device tree is embedded
within (not appended to) the kernel.  I explored embedding the device
tree in the FIT image and saw that I achieved better compression when
it was embedded in the kernel, so I left his original code alone.  Of
course, adding an initramfs is totally blowing up the kernel size, but
that will be my next problem :-)

> If U-Boot size is not such an issue, you could keep this configuration:
> then you could use FIT with single images and TFTP boot during development
> for shorter cycles times. But for permanent deployment you could still
> switch to
> an approach with built-in initramfs and DTB to reduce the size of the
> kernel image.
> Actually MIPS U-Boot can boot all possible combinations of legacy or FIT images
> with bundled or separate initramfs or DTB images,
Oddly enough, while image size of primary concern to me, u-boot size
is not that much of a concern.  Right now, I am using slightly more
than 50% of the size of the NOR flash for u-boot.  So, I could put in
a smaller NOR flash, if I worked at it, but the cost savings would be
minimal.  The rest of the system lives in NAND flash, which, although
there is a lot more of it, there is a lot more to stuff in it, so I am
trying to keep that as small as possible.  Life is odd sometimes :-)

Thanks for the tips.  I appreciate your help.


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