From 89f640bc0405ed1e9c5c5a6cb6c19c8012d11e3f Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 29 Jul 2011 16:35:23 +0100 Subject: [PATCH] hw/nand: Writing to NAND can only clear bits Writing to a NAND device cannot set bits, it can only clear them; implement this rather than simply copying the data. Signed-off-by: Peter Maydell Signed-off-by: Andrzej Zaborowski --- hw/nand.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/hw/nand.c b/hw/nand.c index 1eefe28c56..35804c7e87 100644 --- a/hw/nand.c +++ b/hw/nand.c @@ -75,6 +75,15 @@ struct NANDFlashState { uint32_t ioaddr_vmstate; }; +static void mem_and(uint8_t *dest, const uint8_t *src, size_t n) +{ + /* Like memcpy() but we logical-AND the data into the destination */ + int i; + for (i = 0; i < n; i++) { + dest[i] &= src[i]; + } +} + # define NAND_NO_AUTOINCR 0x00000001 # define NAND_BUSWIDTH_16 0x00000002 # define NAND_NO_PADDING 0x00000004 @@ -595,7 +604,7 @@ static void glue(nand_blk_write_, PAGE_SIZE)(NANDFlashState *s) return; if (!s->bdrv) { - memcpy(s->storage + PAGE_START(s->addr) + (s->addr & PAGE_MASK) + + mem_and(s->storage + PAGE_START(s->addr) + (s->addr & PAGE_MASK) + s->offset, s->io, s->iolen); } else if (s->mem_oob) { sector = SECTOR(s->addr); @@ -606,10 +615,10 @@ static void glue(nand_blk_write_, PAGE_SIZE)(NANDFlashState *s) return; } - memcpy(iobuf + (soff | off), s->io, MIN(s->iolen, PAGE_SIZE - off)); + mem_and(iobuf + (soff | off), s->io, MIN(s->iolen, PAGE_SIZE - off)); if (off + s->iolen > PAGE_SIZE) { page = PAGE(s->addr); - memcpy(s->storage + (page << OOB_SHIFT), s->io + PAGE_SIZE - off, + mem_and(s->storage + (page << OOB_SHIFT), s->io + PAGE_SIZE - off, MIN(OOB_SIZE, off + s->iolen - PAGE_SIZE)); } @@ -624,7 +633,7 @@ static void glue(nand_blk_write_, PAGE_SIZE)(NANDFlashState *s) return; } - memcpy(iobuf + soff, s->io, s->iolen); + mem_and(iobuf + soff, s->io, s->iolen); if (bdrv_write(s->bdrv, sector, iobuf, PAGE_SECTORS + 2) == -1) printf("%s: write error in sector %" PRIu64 "\n", __func__, sector);