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--- linux-2.6.14/drivers/mtd/maps/ixp4xx.c 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14/drivers/mtd/maps/ixp4xx.c 2005-10-29 23:11:24.990820968 -0700
@@ -22,6 +22,7 @@
#include <linux/string.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
+#include <linux/mtd/cfi_endian.h>
#include <linux/mtd/partitions.h>
#include <linux/ioport.h>
#include <linux/device.h>
@@ -30,17 +31,40 @@
#include <linux/reboot.h>
+/* On a little-endian IXP4XX system (tested on NSLU2) an LDRH or STRH
+ * will flip the second address bit - i.e. 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 with pdp-endiannes (on an LE system), however this is not a problem
+ * as the access code consistently only accesses half words - so the
+ * endianness is not determinable on stuff which is written and read
+ * consistently in the little endian world.
+ *
+ * For flash data from the big-endian world, however, the results are
+ * weird - the pdp-endianness results in the data apparently being
+ * 2-byte swapped (as in dd conv=swab). To work round this the 16
+ * bit values are written and read using cpu_to_cfi16 and cfi16_to_cpu,
+ * by default these are no-ops, but if the MTD driver is configed with
+ * CONFIG_MTD_CFI_BE_BYTE_SWAP the macros will byte swap the data,
+ * resulting in a consistently BE view of the flash on both BE (no
+ * op) and LE systems. This config setting also causes the command
+ * data from the CFI implementation to get swapped - as is required
+ * so that this code will *unswap* it and give the correct command
+ * data to the flash.
+ */
#ifndef __ARMEB__
#define BYTE0(h) ((h) & 0xFF)
#define BYTE1(h) (((h) >> 8) & 0xFF)
+#define FLASHWORD(a) (*(__u16*)((u32)(a) ^ 2))
#else
#define BYTE0(h) (((h) >> 8) & 0xFF)
#define BYTE1(h) ((h) & 0xFF)
+#define FLASHWORD(a) (*(__u16*)(a))
#endif
-#define FLASHWORD(a) (*(__u16*)(a))
-#define FLASHVAL(a) FLASHWORD(a)
-#define FLASHSET(a,v) do { FLASHWORD(a) = (v); } while (0)
+#define FLASHVAL(a) cfi16_to_cpu(FLASHWORD(a))
+#define FLASHSET(a,v) (FLASHWORD(a) = cpu_to_cfi16(v))
static map_word ixp4xx_read16(struct map_info *map, unsigned long ofs)
{
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