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path: root/packages/linux/nslu2-kernel/2.6.14/10-ixp4xx-copy-from.patch
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--- linux-2.6.14-rc3/drivers/mtd/maps/ixp4xx.c	2005-10-05 20:35:42.916786530 -0700
+++ linux-2.6.14-rc3/drivers/mtd/maps/ixp4xx.c	2005-10-05 22:42:25.811206514 -0700
@@ -30,18 +30,29 @@
 
 #include <linux/reboot.h>
 
+/* On a little-endian IXP4XX system (tested on NSLU2) contrary to the
+ * Intel documentation LDRH/STRH appears to XOR the address with 10b.
+ * This causes the cfi commands (sent to the command address, 0xAA for
+ * 16 bit flash) to fail.  This is fixed here by XOR'ing the address
+ * before use with 10b.  The cost of this is that the flash layout ends
+ * up consistently big-endian, however this is not a problem as the
+ * access code consistently only accesses half words - so the endianness
+ * is not determinable.
+ */
 #ifndef __ARMEB__
 #define	BYTE0(h)	((h) & 0xFF)
 #define	BYTE1(h)	(((h) >> 8) & 0xFF)
+#define	FLASHW(a)	(*(__u16*)((u32)(a) ^ 2))
 #else
 #define	BYTE0(h)	(((h) >> 8) & 0xFF)
 #define	BYTE1(h)	((h) & 0xFF)
+#define	FLASHW(a)	(*(__u16*)(a))
 #endif
 
 static map_word ixp4xx_read16(struct map_info *map, unsigned long ofs)
 {
 	map_word val;
-	val.x[0] = *(__u16 *) (map->map_priv_1 + ofs);
+	val.x[0] = FLASHW(map->map_priv_1 + ofs);
 	return val;
 }
 
@@ -53,19 +64,23 @@
 static void ixp4xx_copy_from(struct map_info *map, void *to,
 			     unsigned long from, ssize_t len)
 {
-	int i;
-	u8 *dest = (u8 *) to;
-	u16 *src = (u16 *) (map->map_priv_1 + from);
-	u16 data;
+	if (len <= 0)
+		return;
 
-	for (i = 0; i < (len / 2); i++) {
-		data = src[i];
-		dest[i * 2] = BYTE0(data);
-		dest[i * 2 + 1] = BYTE1(data);
+	u8 *dest = (u8 *) to;
+	u8 *src  = (u8 *) (map->map_priv_1 + from);
+	if (from & 1)
+		*dest++ = BYTE1(FLASHW(src-1)), ++src, --len;
+
+	while (len >= 2) {
+		u16 data = FLASHW(src); src += 2;
+		*dest++ = BYTE0(data);
+		*dest++ = BYTE1(data);
+		len -= 2;
 	}
 
-	if (len & 1)
-		dest[len - 1] = BYTE0(src[i]);
+	if (len > 0)
+		*dest++ = BYTE0(FLASHW(src));
 }
 
 /* 
@@ -75,7 +90,7 @@
 static void ixp4xx_probe_write16(struct map_info *map, map_word d, unsigned long adr)
 {
 	if (!(adr & 1))
-	       *(__u16 *) (map->map_priv_1 + adr) = d.x[0];
+	       FLASHW(map->map_priv_1 + adr) = d.x[0];
 }
 
 /* 
@@ -83,7 +98,7 @@
  */
 static void ixp4xx_write16(struct map_info *map, map_word d, unsigned long adr)
 {
-       *(__u16 *) (map->map_priv_1 + adr) = d.x[0];
+       FLASHW(map->map_priv_1 + adr) = d.x[0];
 }
 
 struct ixp4xx_flash_info {