diff options
author | Artem Bityutskiy <artem.bityutskiy@linux.intel.com> | 2012-02-02 13:54:25 +0200 |
---|---|---|
committer | David Woodhouse <David.Woodhouse@intel.com> | 2012-02-04 08:04:57 +0000 |
commit | 500823195d0c9eec2a4637484f30cc93ec633d4a (patch) | |
tree | 9fa140cfce10567d10f5e7e708f71193ff9ec228 /drivers | |
parent | 1a30871fe635d3e92972e6b93e39ff65bb57e52d (diff) |
Revert "mtd: atmel_nand: optimize read/write buffer functions"
This reverts commit fb5427508abbd635e877fabdf55795488119c2d6.
The reason is that it breaks 16 bits NAND flash as it was reported by
Nikolaus Voss and confirmed by Eric BĂ©nard.
Nicolas Ferre <nicolas.ferre@atmel.com> alco confirmed:
"After double checking with designers, I must admit that I misunderstood
the way of optimizing accesses to SMC. 16 bit nand is not so common
those days..."
Reported-by: Nikolaus Voss <n.voss@weinmann.de>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org [3.1+]
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/mtd/nand/atmel_nand.c | 45 |
1 files changed, 41 insertions, 4 deletions
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c index 4dd056e2e16..35b4fb55dbd 100644 --- a/drivers/mtd/nand/atmel_nand.c +++ b/drivers/mtd/nand/atmel_nand.c @@ -161,6 +161,37 @@ static int atmel_nand_device_ready(struct mtd_info *mtd) !!host->board->rdy_pin_active_low; } +/* + * Minimal-overhead PIO for data access. + */ +static void atmel_read_buf8(struct mtd_info *mtd, u8 *buf, int len) +{ + struct nand_chip *nand_chip = mtd->priv; + + __raw_readsb(nand_chip->IO_ADDR_R, buf, len); +} + +static void atmel_read_buf16(struct mtd_info *mtd, u8 *buf, int len) +{ + struct nand_chip *nand_chip = mtd->priv; + + __raw_readsw(nand_chip->IO_ADDR_R, buf, len / 2); +} + +static void atmel_write_buf8(struct mtd_info *mtd, const u8 *buf, int len) +{ + struct nand_chip *nand_chip = mtd->priv; + + __raw_writesb(nand_chip->IO_ADDR_W, buf, len); +} + +static void atmel_write_buf16(struct mtd_info *mtd, const u8 *buf, int len) +{ + struct nand_chip *nand_chip = mtd->priv; + + __raw_writesw(nand_chip->IO_ADDR_W, buf, len / 2); +} + static void dma_complete_func(void *completion) { complete(completion); @@ -235,27 +266,33 @@ err_buf: static void atmel_read_buf(struct mtd_info *mtd, u8 *buf, int len) { struct nand_chip *chip = mtd->priv; + struct atmel_nand_host *host = chip->priv; if (use_dma && len > mtd->oobsize) /* only use DMA for bigger than oob size: better performances */ if (atmel_nand_dma_op(mtd, buf, len, 1) == 0) return; - /* if no DMA operation possible, use PIO */ - memcpy_fromio(buf, chip->IO_ADDR_R, len); + if (host->board->bus_width_16) + atmel_read_buf16(mtd, buf, len); + else + atmel_read_buf8(mtd, buf, len); } static void atmel_write_buf(struct mtd_info *mtd, const u8 *buf, int len) { struct nand_chip *chip = mtd->priv; + struct atmel_nand_host *host = chip->priv; if (use_dma && len > mtd->oobsize) /* only use DMA for bigger than oob size: better performances */ if (atmel_nand_dma_op(mtd, (void *)buf, len, 0) == 0) return; - /* if no DMA operation possible, use PIO */ - memcpy_toio(chip->IO_ADDR_W, buf, len); + if (host->board->bus_width_16) + atmel_write_buf16(mtd, buf, len); + else + atmel_write_buf8(mtd, buf, len); } /* |