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