On Mon, Oct 29, 2007 at 09:40:23AM -0600, Grant Likely wrote: > On 10/29/07, Marian Balakowicz <[EMAIL PROTECTED]> wrote: > > David Gibson wrote: > > > On Thu, Oct 25, 2007 at 05:46:19PM +0200, Marian Balakowicz wrote: > > >> Grant Likely wrote: > > >>> On 10/25/07, Martin Krause <[EMAIL PROTECTED]> wrote: > > > [snip] > > >>>> On a board with 16 MiB FLASH for example the "big-fs" _and_ the "misc" > > >>>> partition could not be used. "big-fs", because the memory is too small > > >>>> (which is OK) and "misc", because it overlaps 1 MiB over the physikal > > >>>> flash border. So only the first 9 MiB of the flash could be used in > > >>>> Linux. > > >>>> The remaining 7 MiB couldn't be accessed. > > >>> Perhaps it would be better to drop the flash layout from the in-kernel > > >>> dts files entirely since flash layout can be a fluid thing. > > >> Well, but that would not be really user friendly, I'd rather stick > > >> with some default config. > > > > > > Strictly speaking the device-tree is not the right place for flash > > > partitioning information. We put it there because it's preferable to > > > having hardcoded per-board flash layouts in the code itself. > > > > > > It only really works well, though, when there are strong conventions > > > (shared with the firmware) about how to partition the flash. > > > > > > Where it's really up to the user to determine how they want to lay out > > > their flash, putting things in the device tree isn't a really good > > > idea. > > > > In principle, you are right, we should not be putting a user dependent > > configuration into .dts files. But on the other hand, bindings have > > been defined for flash-like devices and their partition layouts and > > physmap_of device driver is expecting to get this information from the > > blob. So, it is the place for it. But if we are not to put partition > > layouts into the default kernel .dts files then we should > > provide/maintain some examples an that may be a even bigger mess. > > > > > Incidentally, it's not required that *all* the flash address space be > > > in partitions, so it is possible only give partitions for those flash > > > chunks which the firmware needs to know about. > > > > That might be nicer solution but different variants of TQM5200 boards > > do not share the same subset of partitions (default u-boot partitions > > at least), so it will not help much. > > It's probably more appropriate to have the flash partition layout in > the u-boot environment and have u-boot populate the partition > information in the device tree.
That sounds like a reasonable idea. But if the flash partition layout is *not* fixed - but selectable by the board installer, then it should certainly not be hardcoded into a fixed dts. -- 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_! http://www.ozlabs.org/~dgibson _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev