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.
Yes, it's more appropriate but such feature is not currently available in U-boot, so it has to be hand crafted until then. It just seemed more convenient to have some reference example before there is a support for passing partition layout from firmware. But all right, will remove flash layouts from in-kernel .dts files. Cheers, m. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
