m28w640fst flash: quarduple words write method

[Dmitry]

Hi, All
Kernel: linux-sh4-2.6.11.12_stm20-33
flash:  m28w640fst
This flash is CFI compatible, but it doesn't support buffer write method 
(CFI command - 0xe8). Flash support single (CFI command - 0x10 or 0x40), 
double (CFI command - 0x30) and quadruple (CFI command - 0x56) words 
write method.
MTD supports only single word write method for this flash.
I have implemented double words write method. It works fine.
But I have problem with quadruple word write method implementation.

Part of function:
static int __xipram do_write_quadrupleword(
	struct map_info *map,
	struct flchip *chip,
	unsigned long adr,
	const u_char *buf,
	int len)
{
<...skip...>
         XIP_INVAL_CACHED_RANGE(map, adr, map_bankwidth(map));
         ENABLE_VPP(map);
         xip_disable(map, chip, adr);
         map_write(map, CMD(0x56), adr);

         datum = map_word_ff(map);

         datum = map_word_load(map, buf);
         map_write(map, datum, adr);

         datum = map_word_load(map, buf+2);
         map_write(map, datum, adr+2);

         datum = map_word_load(map, buf+4);
         map_write(map, datum, adr+4);

         datum = map_word_load(map, buf+6);
         map_write(map, datum, adr+6);

         map_write(map,CMD(0x70),adr);
         status = map_read(map, adr);
         printk("--> %s: status %X\n", __FUNCTION__, status);
<...skip...>

Several fist status is 0x80 ('OK'), then function gets status 0x92 
('Program Error' and 'Program/Erase on protected Block, Abort').

Does anybody implement this write method or know what wrong?
Thank you.