diff options
Diffstat (limited to 'drivers/mtd')
| -rw-r--r-- | drivers/mtd/maps/ixp4xx.c | 78 |
1 files changed, 66 insertions, 12 deletions
diff --git a/drivers/mtd/maps/ixp4xx.c b/drivers/mtd/maps/ixp4xx.c index a59f8027903..986c5862839 100644 --- a/drivers/mtd/maps/ixp4xx.c +++ b/drivers/mtd/maps/ixp4xx.c @@ -1,5 +1,5 @@ /* - * $Id: ixp4xx.c,v 1.12 2005/11/07 11:14:27 gleixner Exp $ + * $Id: ixp4xx.c,v 1.13 2005/11/16 16:23:21 dvrabel Exp $ * * drivers/mtd/maps/ixp4xx.c * @@ -34,10 +34,55 @@ #include <linux/reboot.h> +/* + * Read/write a 16 bit word from flash address 'addr'. + * + * When the cpu is in little-endian mode it swizzles the address lines + * ('address coherency') so we need to undo the swizzling to ensure commands + * and the like end up on the correct flash address. + * + * To further complicate matters, due to the way the expansion bus controller + * handles 32 bit reads, the byte stream ABCD is stored on the flash as: + * D15 D0 + * +---+---+ + * | A | B | 0 + * +---+---+ + * | C | D | 2 + * +---+---+ + * This means that on LE systems each 16 bit word must be swapped. Note that + * this requires CONFIG_MTD_CFI_BE_BYTE_SWAP to be enabled to 'unswap' the CFI + * data and other flash commands which are always in D7-D0. + */ #ifndef __ARMEB__ +#ifndef CONFIG_MTD_CFI_BE_BYTE_SWAP +# error CONFIG_MTD_CFI_BE_BYTE_SWAP required +#endif + +static inline u16 flash_read16(void __iomem *addr) +{ + return be16_to_cpu(__raw_readw((void __iomem *)((unsigned long)addr ^ 0x2))); +} + +static inline void flash_write16(u16 d, void __iomem *addr) +{ + __raw_writew(cpu_to_be16(d), (void __iomem *)((unsigned long)addr ^ 0x2)); +} + #define BYTE0(h) ((h) & 0xFF) #define BYTE1(h) (((h) >> 8) & 0xFF) + #else + +static inline u16 flash_read16(const void __iomem *addr) +{ + return __raw_readw(addr); +} + +static inline void flash_write16(u16 d, void __iomem *addr) +{ + __raw_writew(d, addr); +} + #define BYTE0(h) (((h) >> 8) & 0xFF) #define BYTE1(h) ((h) & 0xFF) #endif @@ -45,7 +90,7 @@ static map_word ixp4xx_read16(struct map_info *map, unsigned long ofs) { map_word val; - val.x[0] = le16_to_cpu(readw(map->virt + ofs)); + val.x[0] = flash_read16(map->virt + ofs); return val; } @@ -57,19 +102,28 @@ static map_word ixp4xx_read16(struct map_info *map, unsigned long ofs) static void ixp4xx_copy_from(struct map_info *map, void *to, unsigned long from, ssize_t len) { - int i; u8 *dest = (u8 *) to; void __iomem *src = map->virt + from; - u16 data; - for (i = 0; i < (len / 2); i++) { - data = le16_to_cpu(readw(src + 2*i)); - dest[i * 2] = BYTE0(data); - dest[i * 2 + 1] = BYTE1(data); + if (len <= 0) + return; + + if (from & 1) { + *dest++ = BYTE1(flash_read16(src)); + src++; + --len; } - if (len & 1) - dest[len - 1] = BYTE0(le16_to_cpu(readw(src + 2*i))); + while (len >= 2) { + u16 data = flash_read16(src); + *dest++ = BYTE0(data); + *dest++ = BYTE1(data); + src += 2; + len -= 2; + } + + if (len > 0) + *dest++ = BYTE0(flash_read16(src)); } /* @@ -79,7 +133,7 @@ static void ixp4xx_copy_from(struct map_info *map, void *to, static void ixp4xx_probe_write16(struct map_info *map, map_word d, unsigned long adr) { if (!(adr & 1)) - writew(cpu_to_le16(d.x[0]), map->virt + adr); + flash_write16(d.x[0], map->virt + adr); } /* @@ -87,7 +141,7 @@ static void ixp4xx_probe_write16(struct map_info *map, map_word d, unsigned long */ static void ixp4xx_write16(struct map_info *map, map_word d, unsigned long adr) { - writew(cpu_to_le16(d.x[0]), map->virt + adr); + flash_write16(d.x[0], map->virt + adr); } struct ixp4xx_flash_info { |