MT7621_SPI_OPCODE
val = mt7621_spi_read(rs, MT7621_SPI_OPCODE + (len & ~3));
mt7621_spi_write(rs, MT7621_SPI_OPCODE + len - 4, val);
mt7621_spi_write(rs, MT7621_SPI_OPCODE + (len & ~3), val);