I like the idea of a new virtual filesystem.
The proc code is quite simple and straightforward, whereas i quickly
fell into a snakepit of interrelated structs when I tried to grok
sysfs. And the text representation requirement is a problem because OFW
device tree properties have specific serialization rules that include
binary data in many cases.
The API for /proc is just fine. I wonder if we could essentially clone
it (or even reuse most of the functions verbatim), but mount it on /ofw .
Jonathan Corbet wrote:
Mitch Bradley <[EMAIL PROTECTED]> wrote:
/proc/device-tree is working. It requires a kernel patch and a
(fairly low risk) firmware change. Andres suggests that we try it out
as-it, without first converting it to sysfs, and publicize it on LKML
to get feedback. When Corbet reappears, we will ask him for help with
the sysfs conversion if that turns out to be necessary. Andres will
help Mitch package the patches.
I've reappeared - sort of. Current weather forecasts suggest that some
skiing time before school restarts may be mandatory.
If I understand this patch, it's a means for exporting the firmware's
view of the hardware to user space. I can pretty well guarantee that
any implementation based on /proc is not going to get into the mainline
kernel. I, personally, would not even post it.
Sysfs is more possible. Some thoughts on that:
- Sysfs already implements a representation of the device tree. It's
worth pondering whether that representation can be extended to
contain the desired information.
- There are some firm rules about sysfs files; among other things, each
must contain exactly one value in a textual representation. So some
of the /proc/device-tree files would have to be reworked to meet
those expectations.
An alternative which may be worth considering is simply creating a new
virtual filesystem. We could create olpcfs, put anything we want into
it, and there should be few complaints. It could be mounted on /olpc or
wherever. And it would all be pretty easy to do.
Just a thought.
jon
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