On 11/30/2012 9:27 AM, Kent A. Reed wrote:
> On 11/30/2012 8:51 AM, Yishin Li wrote:
>> On Fri, Nov 30, 2012 at 9:25 PM, Kent A. Reed
>> <[email protected]>wrote:
>>
>>>
>>> ... is there a specific BeagleBone BSP floating around? Honestly, I
>>> don't know enough to know if this really matters but the fact that
>>> we're
>>> working with the PRUs as well as the ARM core makes me wonder.
>>>
>>> Regards,
>>> Kent
>>>
>>>
>> Per the "Working with meta-ti", there's beaglebone.conf in the
>> meta-ti BSP. https://wiki.yoctoproject.org/wiki/images/b/b3/Meta-ti.pdf
>>
>> Yishin
>>
>
> Thanks, Yishin.
>
> Not having had the time to read all the Yocto documentation, notably
> the BSP Developer's Guide, I don't know whether a BSP gets down to
> nitty-gritty details of the board and passes compiler flags etc to the
> toolchain accordingly or if it merely makes it easy to wrap all the
> software resources in one blanket. My FINO (First-in, Never-out) stack
> contains many reading assignments like this one :)
>
> Joking aside, I have accumulated some limited-resource ARM boards and
> appliances for which I'd like to create custom BSPs and for which
> there are no member-sponsors in the Yocto Project doing the work for
> me. It's a nonstarter to build anything complicated, certainly not a
> kernel, directly on these boards; the CPU power and RAM size are just
> too limiting even if NFS gives access to adequate storage.
>
> When I had just one device, OpenEmbedded/BitBake worked well enough ...
>
> Regards,
> Kent
>
I reread this message thread earlier today and realized that it would
confuse folks who haven't followed developments in cross-compiling, not
to mention make those who have wonder what I was smoking.
In the interest of reducing confusion, let me say that
---
BitBake is a make-alike build tool with the special focus of
distributions and packages for embedded Linux cross compilation. A
recipe tells BitBake how to build a particular package. It includes all
the package dependencies, sources to fetch the source code from,
configuration, compilation, build, install and remove instructions. It
stores the metadata for the package in standard variables. The BitBake
recipes consist of the source URL (http, https, ftp, cvs, svn, git,
local file system location) of the package, dependencies and compile or
install options. During the build process they are used to track
dependencies, performing native or cross-compile of the package and pack
it up so that it's suitable to be installed on the local or target
device. It's also possible to create complete images, consisting of root
file system and kernel. [description excerpted from the Wikipedia article]
OpenEmbedded is a software framework to create Linux distributions aimed
for, but not restricted to, embedded devices. The build system is based
on BitBake recipes. Recipes in the old OpenEmbedded-Classic were all
found in one place, in the new OpenEmbedded-Core the structure has
changed into meta layers to make it easier to add custom recipes.
[description excerpted from the Wikipedia article].
Aside: I cut my eyeteeth on OpenEmbedded-Classic. It was that "all
found in one place" that caused me heartburn as I tried to deal with
multiple boards and their hardware idiosyncrasies.
The Yocto Project is a Linux Foundation workgroup whose goal is to
produce tools and processes that will enable the creation of Linux
distributions for embedded software that are independent of the
underlying architecture of the embedded software itself. The project has
aligned itself with OpenEmbedded, an existing framework with similar
goals, with the result being The OpenEmbedded-Core Project. The Yocto
Project itself is an open source project whose focus is on improving the
software development process for embedded Linux distributions. The Yocto
Project provides interoperable tools, metadata, and processes that
enable the rapid, repeatable development of Linux-based embedded
systems. [description excerpted from the Wikipedia article]
Aside: I won't bore y'all with details, but if you're dealing with
multiple embedded architectures and haven't looked at the Yocto Project
then I suggest you do. Key phrases from the Wikipedia article include:
"attempting to improve the lives of developers of customised Linux
systems supporting the ARM, MIPS, PowerPC and x86/x86_64 architectures",
"focusing on one set of great tools rather than the several sets of
mediocre ones", "open source build system, based around the OpenEmbedded
architecture", "interoperability among these tools."
---
So, Yocto does not replace OpenEmbedded and BitBake, as one might infer
from my previous message, rather it incorporates them into a more
manageable whole.
The Yocto Project introduced the notion of meta layers in descriptions
of resources and targets. It is this notion that caused the OpenEmbedded
project to create OpenEmbedded-Core. Both rely on BitBake (now
co-maintained by both) and recipes, so when I asked Yishin about a
BeagleBone BSP that was my cryptic way of asking for appropriate recipes
and a BSP that references them appropriately. The PDF file he cited (a
presentation slide set) helps put it in context.
---
I hope I've cleared the air.
I should have known better than rush my reply to Yishin. I was in a
hurry (had to get my wife to yet another consultation), stressed (ibid),
and shooting from the hip without refreshing my memory about work I
haven't touched for some time. Sigh. Growing old isn't for sissies.
Regards,
Kent
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