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Revert "mtd: atmel_nand: optimize read/write buffer functions"

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This reverts commit fb5427508a.

The reason is that it breaks 16 bits NAND flash as it was reported by
Nikolaus Voss and confirmed by Eric Bénard.

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+]
This commit is contained in:
Artem Bityutskiy 2012-02-02 13:54:25 +02:00 committed by David Woodhouse
parent 1a30871fe6
commit 500823195d
1 changed files with 41 additions and 4 deletions
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45
drivers/mtd/nand/atmel_nand.c
View file

@ -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 @@ 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 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);
}
/*