--- 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 #include #include +#include #include #include #include @@ -30,17 +31,40 @@ #include +/* 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) {