From f9cbf973313de4d727d2b3237a5b40b791142429 Mon Sep 17 00:00:00 2001 From: Ladislav Michl Date: Sat, 12 Jan 2019 13:58:28 +0100 Subject: mtd: core: Fix erase area alignment for non power of 2 erasesize On Thu, Jan 10, 2019 at 09:32:07AM +0100, Sascha Hauer wrote: > On Wed, Jan 09, 2019 at 12:28:14PM +0100, Ladislav Michl wrote: > > Devices as AT45DB161 DataFlash uses non power of two page size (528) > > while present alignment algorithm relies on erasesize being power > > of 2. > > Fix that by introducing helper functions rounding to any multiply. > > Note that logic is sligthly changed to be consistent as ending > > address is moved forward to include also last byte meant to be > > erased while previous implementation moved it backward. > > > > Signed-off-by: Ladislav Michl > > --- > > drivers/mtd/core.c | 28 ++++++++++++++++++++++------ > > include/linux/kernel.h | 5 +++++ > > 2 files changed, 27 insertions(+), 6 deletions(-) > > Applied, thanks Hi Sascha, I was searching for paper bag, but was unable to find anything thick enouh to cover behind :-/ This version is buggy and I noticed right now when testing on another board. Corrected version follows, which is also 192 bytes shorter for my ARM target. It seems next branch at https://git.pengutronix.de/ is not yet updated, so perhaps my fault won't affect anyone. Signed-off-by: Sascha Hauer --- drivers/mtd/core.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) (limited to 'drivers/mtd') diff --git a/drivers/mtd/core.c b/drivers/mtd/core.c index d3cbe502fa..f44c6cfc69 100644 --- a/drivers/mtd/core.c +++ b/drivers/mtd/core.c @@ -141,15 +141,28 @@ static struct mtd_erase_region_info *mtd_find_erase_region(struct mtd_info *mtd, return NULL; } +static loff_t __mtd_erase_round(loff_t x, uint32_t esize, int up) +{ + uint64_t dividend = x; + uint32_t mod = do_div(dividend, esize); + if (mod == 0) + return x; + if (up) + x += esize; + return x - mod; +} +#define mtd_erase_round_up(x, esize) __mtd_erase_round(x, esize, 1) +#define mtd_erase_round_down(x, esize) __mtd_erase_round(x, esize, 0) + static int mtd_erase_align(struct mtd_info *mtd, loff_t *count, loff_t *offset) { struct mtd_erase_region_info *e; loff_t ofs; if (mtd->numeraseregions == 0) { - ofs = *offset & ~(loff_t)(mtd->erasesize - 1); - *count += (*offset - ofs); - *count = ALIGN(*count, mtd->erasesize); + ofs = mtd_erase_round_down(*offset, mtd->erasesize); + *count += *offset - ofs; + *count = mtd_erase_round_up(*count, mtd->erasesize); *offset = ofs; return 0; } @@ -158,14 +171,14 @@ static int mtd_erase_align(struct mtd_info *mtd, loff_t *count, loff_t *offset) if (!e) return -EINVAL; - ofs = *offset & ~(e->erasesize - 1); - *count += (*offset - ofs); + ofs = mtd_erase_round_down(*offset, e->erasesize); + *count += *offset - ofs; e = mtd_find_erase_region(mtd, *offset + *count); if (!e) return -EINVAL; - *count = ALIGN(*count, e->erasesize); + *count = mtd_erase_round_up(*count, e->erasesize); *offset = ofs; return 0; -- cgit v1.2.3