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Commit fb542750 authored by Nicolas Ferre's avatar Nicolas Ferre Committed by Artem Bityutskiy
Browse files

mtd: atmel_nand: optimize read/write buffer functions 



For PIO NAND access functions, we use the features of the SMC:
- no need to take into account the NAND bus width: SMC will deal with this
- use of an IO memcpy on the NAND chip-select space is able to generate
  proper SMC behavior.

Signed-off-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: default avatarArtem Bityutskiy <dedekind1@gmail.com>
parent 57b078a0

drivers/mtd/nand/atmel_nand.c

+4 −41
Original line number Diff line number Diff line
@@ -161,37 +161,6 @@ 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);
@@ -266,33 +235,27 @@ static int atmel_nand_dma_op(struct mtd_info *mtd, void *buf, int len, 
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 (host->board->bus_width_16)

		atmel_read_buf16(mtd, buf, len);

	else

		atmel_read_buf8(mtd, buf, len);

	/* if no DMA operation possible, use PIO */

	memcpy_fromio(buf, chip->IO_ADDR_R, 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 (host->board->bus_width_16)

		atmel_write_buf16(mtd, buf, len);

	else

		atmel_write_buf8(mtd, buf, len);

	/* if no DMA operation possible, use PIO */

	memcpy_toio(chip->IO_ADDR_W, buf, len);

}



/*