On Mon, May 28, 2012 at 09:27:32PM +0300, Daniel Golle wrote:
> On 28/05/12 20:38, Luka Perkov wrote:
> > I got feedback from Kaloz regarding ubifs - we should boot from
> > squashfs, and create ubifs after that.
> I'm using a single UBI mtd partition and having two volumes:
> One "static" (r/o in UBI terminology) for rom (i.e. what used to be the 
> content
> of squashfs, but including the kernel-uImage) and one "dynamic" (overlay, what
> used to be JFFS2) for the user to change. Apparently UBI is by far not as
> efficient as squashfs... However, it got the advantage that U-Boot can read 
> from
> it and we won't need an extra volume (or even worse: mtd partition) for the
> kernel-uImage, but it can be just a regular file, which is most transparent 
> for
> the user.

Ok. Do you have any patches for this?

> Besides space-efficiency (which is not so much an issue on most platforms 
> using
> NAND anyway), what speaks against a static UBIFS for the factory FS?

I dont know, I use only one UBI volume and it works fine.

> Alternatively, the uImage could be a seperate UBI volume and we could use
> squashfs using gluebi (or make squashfs work on UBI volumes instead of MTD
> partitions).
> 
> In the end of the day, what matters most is just having everything inside UBI
> volumes and having U-Boot as well as U-Boot environment redundant.

How can U-Boot environment be redundant? Is that uboot patch?

> In that way,
> no single NAND bad-block can ever brick the device (but you can still loose
> data, obviously or have your factory/rootfs destroyed). How and what we use
> *inside* UBI (uImage-volume+squashfs-volume+ubifs-overlay-volume vs.
> ubifs-rom-volume-including-uImage+ubifs-overlay-volume) is a matter of taste.

I would go with second one 
(ubifs-rom-volume-including-uImage+ubifs-overlay-volume).

> Both ways have advantages and disadvantages:
> Increased efficiency comes together with increased complexity -- personally 
> I'd
> be more happy to waste a couple of megs of nand (usually we got plenty) for
> having a simple solution using just one type of filesystem and storage 
> subsystem.

I agree.

> >> I recently also updated Das U-Boot to the most recent stable version which 
> >> now
> >> got very well working support for UBIFS, in that way, the bootloader can
> >> (similarly to GRUB on x86) read the kernel-uImage from the filesystem which
> >> makes things much more transparent for the user. 
> > This is true. I'm using this setup on my kirkwood unit. I use upstream
> > uboot.
> Having it built automatically using the OpenWrt toolchain would be nice.
> See
> https://lists.openwrt.org/pipermail/openwrt-devel/2012-May/015291.html
> https://lists.openwrt.org/pipermail/openwrt-devel/2012-May/015292.html
> https://lists.openwrt.org/pipermail/openwrt-devel/2012-May/015293.html

That looks ok to me...

> Is there any reason why this cannot be included/updated?
> 
> >> As I got no reaction on that at all, I seems like the kirkwood target is
> >> abandoned, which is a petty for that very developer-friendly platform 
> >> which is
> >> the first embedded platform for many new-commers in the field.
> >> What's the situation?
> > I'm planning to resend the patches. Also, I would like to rework scripts
> > so we have something like: target/linux/lantiq/base-files/lib/
> Great to see things are moving forward. I got the resources to be working on
> that matter most of the time in the next two days. I'll be happy to 
> cross-review
> and discuss things with you. (I'll be on #openwrt-devel most of the day 
> tomorrow
> and Tuesday as well, I'm in GMT+2, but I don't get up too early :)

You can find me also there (luka12345).

Luka
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