[MTD] [NAND] S3C2410: Deal with unaligned lengths in S3C2440 buffer read/write

Add code to deal with fractional lengths, as reported by
Werner Almesberger. Re-work of his original patch.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>

drivers/mtd/nand/s3c2410.c

@@ -584,7 +584,16 @@ static void s3c2410_nand_read_buf(struct mtd_info *mtd, u_char *buf, int 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);
+
+	readsl(info->regs + S3C2440_NFDATA, buf, len >> 2);
+
+	/* cleanup if we've got less than a word to do */
+	if (len & 3) {
+		buf += len & ~3;
+
+		for (; len & 3; len--)
+			*buf++ = readb(info->regs + S3C2440_NFDATA);
+	}
 }
 
 static void s3c2410_nand_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
@@ -596,7 +605,16 @@ static void s3c2410_nand_write_buf(struct mtd_info *mtd, const u_char *buf, int
 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);
+
+	writesl(info->regs + S3C2440_NFDATA, buf, len >> 2);
+
+	/* cleanup any fractional write */
+	if (len & 3) {
+		buf += len & ~3;
+
+		for (; len & 3; len--, buf++)
+			writeb(*buf, info->regs + S3C2440_NFDATA);
+	}
 }
 
 /* cpufreq driver support */