[MTD] [NAND] add s3c2440-specific read_buf/write_buf

Add read_buf/write_buf for s3c2440, which can read/write 32 bits at a
time rather than just 8. In my testing on an s3c2440a running at 400 MHz
with a 100 MHz HCLK, read performance improves by 36% (from 5.19 MB/s
to 7.07 MB/s).
Signed-off-by: Matt Reimer <mreimer@vpop.net>
Acked-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/nand/s3c2410.c

@@ -488,12 +488,24 @@ static void s3c2410_nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
 	readsb(this->IO_ADDR_R, buf, len);
 }
 
+static void s3c2440_nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
+{
+	struct s3c2410_nand_info *info = s3c2410_nand_mtd_toinfo(mtd);
+	readsl(info->regs + S3C2440_NFDATA, buf, len / 4);
+}
+
 static void s3c2410_nand_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
 {
 	struct nand_chip *this = mtd->priv;
 	writesb(this->IO_ADDR_W, buf, len);
 }
 
+static void s3c2440_nand_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
+{
+	struct s3c2410_nand_info *info = s3c2410_nand_mtd_toinfo(mtd);
+	writesl(info->regs + S3C2440_NFDATA, buf, len / 4);
+}
+
 /* device management functions */
 
 static int s3c2410_nand_remove(struct platform_device *pdev)
@@ -604,6 +616,8 @@ static void s3c2410_nand_init_chip(struct s3c2410_nand_info *info,
 		info->sel_bit	= S3C2440_NFCONT_nFCE;
 		chip->cmd_ctrl  = s3c2440_nand_hwcontrol;
 		chip->dev_ready = s3c2440_nand_devready;
+		chip->read_buf  = s3c2440_nand_read_buf;
+		chip->write_buf	= s3c2440_nand_write_buf;
 		break;
 
 	case TYPE_S3C2412: