[coreboot] How to find out "page size" of a flash chip?

[FENG Yu Ning]

In flashchip.c, there is (just an example),

/* Vendor	Chip			...	Page size (B)	...	*/
    ...
    {"SST",		"SST25VF040B",	...	256,		...	},

How to find out the number 256? I have read through the datasheet of
that chip, which mentioned 4K sector, 32K and 64K blocks, but no
"page". There is neither an operation which needs an address with
value 0 in the least significant 8 bits.

Or, the number does not come out of a datasheet?

Thanks,
yu ning