Hi Brian, On Thu, Dec 10, 2015 at 9:54 PM, Brian Norris <computersforpeace@xxxxxxxxx> wrote: > On Sat, Dec 05, 2015 at 11:15:54AM +0100, Geert Uytterhoeven wrote: >> On Sat, Dec 5, 2015 at 6:19 AM, Brian Norris >> <computersforpeace@xxxxxxxxx> wrote: >> > There have been several discussions [1] about adding a device tree binding for >> > associating flash devices with the partition parser(s) that are used on the >> > flash. There are a few reasons: >> > >> > (1) drivers shouldn't have to be encoding platform knowledge by listing what >> > parsers might be used on a given system (this is the currently all that's >> > supported) >> > (2) we can't just scan for all supported parsers (like the block system does), since >> > there is a wide diversity of "formats" (no standardization), and it is not >> > always safe or efficient to attempt to do so, particularly since many of >> > them allow their data structures to be placed anywhere on the flash, and >> > so require scanning the entire flash device to find them. >> >> I read the second reason, but would it be useful to (partially) merge >> block/partitions/ and drivers/mtd/partitions/, so I can use e.g. msdos >> partitions >> on an mtd device?? > > I kinda agree with Michal: is there a good use case? I don't have an immediate use case. Just looking at it from a high-level viewpoint. > Really, MTD partitioning is not a highly-scalable design. Particularly, > it's not typically that well-suited to large (read: unreliable) NAND > flash, where fixing partitions at the raw flash level mostly serves to > restrict UBI's ability to wear-level across the device. For that sort of > case, it's best if people are using UBI volumes on a (mostly?) > unpartitioned MTD, instead of using MTD partitions as the main > separation mechanism. Also, most partition designs (either MTD or block) > aren't very robust against bitflips, read disturb, etc. > > IOW, I wouldn't expect MBR or GPT to work well on large raw NAND flash, > and so I don't plan to do that sort of work myself. If you can provide > some better argument for it, and some nice maintainable code to go with > it, then of course it could be considered :) There's also NOR FLASH (e.g. SPI-NOR), which is what most boards I'm working on have. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html