From 061d6b14b3b59f140371baa0f98963f761a7080f Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Thu, 2 Feb 2012 13:54:25 +0200 Subject: [PATCH] Revert "mtd: atmel_nand: optimize read/write buffer functions" MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 500823195d0c9eec2a4637484f30cc93ec633d4a upstream. 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 Bénard. Nicolas Ferre 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 Acked-by: Nicolas Ferre Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- drivers/mtd/nand/atmel_nand.c | 45 +++++++++++++++++++++++++++++++---- 1 file changed, 41 insertions(+), 4 deletions(-) diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c index 23e5d77c39fc..ee6e26e78a1a 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); } /* -- 2.39.2