[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>

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c
index d315b513db5c..8a7f960a0df5 100644
--- a/drivers/mtd/nand/s3c2410.c
+++ b/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 */