可从下面的地址下载对应的 spec：

http://www.datasheetcatalog.com/info_redirect/datasheets2/13/132042_1.pdf.shtml

Ｍ20PXX (512 Kbit to 32 Mbit, Low Voltage, Serial Flash Memory With 40 MHz or 50 MHz SPI Bus Interface)

对应Linux的代码在：

driver/mtd/devices/m25p80.c