Re: OF compatible MTD platform RAM driver ?

David Gibson
2008-03-27T10:03:15Z

On Thu, Mar 27, 2008 at 10:13:32AM +0100, Laurent Pinchart wrote:
> On Wednesday 26 March 2008 13:53, Sergei Shtylyov wrote:
> > Laurent Pinchart wrote:
[snip]
> > Heh, we've gone thru "physmap" before -- it was labelled Linux-specific
> > name (well, I'd agree with that).
>
> physmap stands for physically mapped. That doesn't sound
> Linux-specific to me, the fact that the MTD driver has the same name
> is a pure coincidence. linmap-rom and linmap-rom sound even more
> Linux-specific :-)

It may not be Linux specific per se, but it's a bad name, because the
fact that the device is physically direct mapped isn't a useful
distinguishing feature of the device. Main memory is also direct
physically mapped, after all, but that's not what you want to cover
with this description. In general how a device is wired is described
by where it sits in the tree, not by its properties.

It only seems like a usefully distinguishing name because it's the
Linux "physmap_of" driver that uses it. So in this sense it is a
Linux specific name after all. In fact, physmap_of is itself very
badly named - right now it only handles direct mapped mtds, but that's
not inherent; it could be trivially extended to also instantiate a
non-direct-mapped device (as long as the underlying mtd layer
supported it, of course). It bears no relation at all to the
"physmap" driver, except historical accident.

> Could we agree on a name ? I'd like to submit a new patch.

For ROMs I think just plain "rom" should be sufficient. For RAMs we
need something to indicate that it's memory but intended for secondary
storage, not as main memory. Unfortunately, I'm finding myself unable
to think of something.

--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!