Patrick Rudolph has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/31019 )
Change subject: spi/winbond.c: change protection_granularity_shift for W25Q256* from 16 to 19 ......................................................................
Patch Set 1:
For SEC=0:
https://www.winbond.com/resource-files/w25q256jv%20spi%20revb%2009202016.pdf Page 20 The smallest "Protected density" is 64KB which is 1 << 16.
https://www.winbond.com/resource-files/w25q128fv_revhh1_100913_website1.pdf Page 22 The smallest "Protected density" is 256KB which is 1 << 18.