On Tue, Aug 27, 2013 at 07:19:18PM -0700, Brian Norris wrote: > Some bright specification writers decided to write this in the ONFI spec > (from ONFI 3.0, Section 3.1): > > "The number of blocks and number of pages per block is not required to > be a power of two. In the case where one of these values is not a > power of two, the corresponding address shall be rounded to an > integral number of bits such that it addresses a range up to the > subsequent power of two value. The host shall not access upper > addresses in a range that is shown as not supported." > > This breaks every assumption MTD makes about NAND block/chip-size > dimensions -- they *must* be a power of two! > > And of course, an enterprising manufacturer has made use of this lovely > freedom. Exhibit A: Micron MT29F32G08CBADAWP > > "- Plane size: 2 planes x 1064 blocks per plane > - Device size: 32Gb: 2128 blockss [sic]" > > This quickly hits a BUG() in nand_base.c, since the extra dimensions > overflow so we think it's a second chip (on my single-chip setup): > > ONFI param page 0 valid > ONFI flash detected > NAND device: Manufacturer ID: 0x2c, Chip ID: 0x44 (Micron MT29F32G08CBADAWP), 4256MiB, page size: 8192, OOB size: 744 > ------------[ cut here ]------------ > kernel BUG at drivers/mtd/nand/nand_base.c:203! > Internal error: Oops - BUG: 0 [#1] SMP ARM > [... trim ...] > [<c02cf3e4>] (nand_select_chip+0x18/0x2c) from [<c02d25c0>] (nand_do_read_ops+0x90/0x424) > [<c02d25c0>] (nand_do_read_ops+0x90/0x424) from [<c02d2dd8>] (nand_read+0x54/0x78) > [<c02d2dd8>] (nand_read+0x54/0x78) from [<c02ad2c8>] (mtd_read+0x84/0xbc) > [<c02ad2c8>] (mtd_read+0x84/0xbc) from [<c02d4b28>] (scan_read.clone.4+0x4c/0x64) > [<c02d4b28>] (scan_read.clone.4+0x4c/0x64) from [<c02d4c88>] (search_bbt+0x148/0x290) > [<c02d4c88>] (search_bbt+0x148/0x290) from [<c02d4ea4>] (nand_scan_bbt+0xd4/0x5c0) > [... trim ...] > ---[ end trace 0c9363860d865ff2 ]--- > > So to fix this, just truncate these dimensions down to the greatest > power-of-2 dimension that is less than or equal to the specified > dimension. > > Signed-off-by: Brian Norris <computersforpeace@xxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> I've not heard any comments about this, but I've been using this patch for a few months on most of my kernels, and I just ran into another (unpatched) kernel/board that trips over this same problem. Unless someone screams... ... applied to l2-mtd.git, with CC -stable. Although it is a bugfix, I think it should wait until next merge window so it can sit in -next for a while. Brian -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html