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Commit 3c773547 authored by John Bowler's avatar John Bowler Committed by Thomas Gleixner
Browse files

[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: default avatarJohn Bowler <jbowler@acm.org>
Signed-off-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarDavid Vrabel <dvrabel@arcom.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 987d2401

drivers/mtd/maps/ixp4xx.c

+66 −12
Original line number Diff line number Diff line 
/*

 * $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;

	}



	while (len >= 2) {

		u16 data = flash_read16(src);

		*dest++ = BYTE0(data);

		*dest++ = BYTE1(data);

		src += 2;

		len -= 2;

        }



	if (len & 1)

		dest[len - 1] = BYTE0(le16_to_cpu(readw(src + 2*i)));

	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 {