Userspace write to UBI partitions

[Shmulik Ladkani]

On Tue, 7 Feb 2012 17:36:25 +0100 (CET) Ricard Wanderlof <ricard.wanderlof at axis.com> wrote:
> 
> On Tue, 7 Feb 2012, Shmulik Ladkani wrote:
> 
> > On Tue, 7 Feb 2012 16:20:58 +0100 (CET) Ricard Wanderlof <ricard.wanderlof at axis.com> wrote:
> >>
> >> Is it possible to do a userspace write to a UBI volume as if it were plain
> >> flash memory, i.e. should I be able to do "cat somefile > /dev/ubi0_0" ? I
> >> get a 'Write Error: Operation not permitted' when I do this (Linux 2.6.35)
> >> but I'm pretty sure that I've used UBI volumes that way in the past, may
> >> have been with older kernels then.
> >
> > Is your volume dynamic or static?
> 
> I tried both, but given the nature of the data we want to keep in the 
> volume it should really be dynamic.
> 
> > If dynamic, have you tried setting the UBI_VOL_PROP_DIRECT_WRITE
> > property by issuing a UBI_IOCSETVOLPROP volume ioctl?
> > (formerly named UBI_PROP_DIRECT_WRITE and UBI_IOCSETPROP)
> 
> Thanks for the pointer, I've never noticed this ioctl before.
> 
> I'll try this out. In the meantime, there doesn't seem to be an ioctl for 
> erasing blocks?
> 

Well, another option would be using Gluebi - (CONFIG_MTD_UBI_GLUEBI).
It exposes a "regular" mtd for every existing volume.

You'd be able to work using standard mtd interfaces on it (mtdchar
ioctls, e.g. MEMERASE, or even the mtdblock abstraction).

Regards,
Shmulik