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[MTD] maps/ixp4xx: half-word boundary and little-endian fixups 

ixp4xx updates:
  - Handle reads that don't start on a half-word boundary.
  - Make it work when CPU is in little-endian mode.

Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: David Vrabel <dvrabel@arcom.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
John Bowler 2005-11-16 16:23:25 +00:00 committed by Thomas Gleixner
parent 987d24018d
commit 3c77354794
1 changed files with 66 additions and 12 deletions
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78
drivers/mtd/maps/ixp4xx.c
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@ -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 {