6455配置回环模式（LOOPBACK）我就改了SRIO_PER_SET_CNTL = 0x0600026F;

怎么没法设置loopback，下面是我的一些设置

SRIO_GBL_EN  = 0x00000001 ;
 SRIO_BLK0_EN = 0x00000001 ; //MMR_EN
 SRIO_BLK5_EN = 0x00000001 ; //PORT0_EN
 SRIO_BLK1_EN = 0x00000001 ; //LSU_EN
 SRIO_BLK2_EN = 0x00000001 ; //MAU_EN
 SRIO_BLK3_EN = 0x00000001 ; //TXU_EN
 SRIO_BLK4_EN = 0x00000001 ; //RXU_EN
 SRIO_BLK6_EN = 0x00000001 ; //PORT1_EN
 SRIO_BLK7_EN = 0x00000001 ; //PORT2_EN
 SRIO_BLK8_EN = 0x00000001 ; //PORT3_EN

 SRIO_PER_SET_CNTL = 0x0600026F;// 0x0400026F ;

 SRIO_SERDES_CFG0_CNTL = 0x0000000B;//mpy=00101b pll 10x;pllen=1;
 SRIO_SERDES_CFGRX0_CNTL = 0x00081101 ; // enable rx, rate=00 full rate; EQ=0001 adaptive; align=01 Comma alignment enabled;
 SRIO_SERDES_CFGTX0_CNTL = 0x00010801 ; // enable tx, rate=00 full rate; swing=100:750mv;

 SRIO_DEVICEID_REG1 = 0 ; // id-16b=0000, id-08b=00
 SRIO_DEVICEID_REG2 = 0 ; // id-16b=0000, id-08b=00