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: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Artem Bityutskiy <dedekind1@gmail.com>

diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index ee6e26e..23e5d77 100644 (file)
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -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 @@ 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 (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);
 }
 
 /*