强制开放MPSoC的PS-PL接口

MPSoC含有PS、PL；在PS和PL之间有大量接口和信号线，比如AXI、时钟、GPIO等。缺省情况下，PS和PL之间有接口和信号线被关闭。加载bit后，软件才会打开PS和PL之间的接口和信号线。比如在文件xfsbl_partition_load.c中，FSBL加载FPGA的bit后会执行下列操作，打开PS和PL之间的接口和信号线：

static u32 XFsbl_PartitionValidation(XFsblPs * FsblInstancePtr,
                                          u32 PartitionNum)
{
	......
	
#ifdef XFSBL_BS
       if (DestinationDevice == XIH_PH_ATTRB_DEST_DEVICE_PL) {
              Status = XFsbl_PLWaitForDone();
              if (Status != XFSBL_SUCCESS) {
                     goto END;
              }

              /**
              * PL is powered-up before its configuration, but will be in isolation.
              * Now since PL configuration is done, just remove the isolation
              */
              psu_ps_pl_isolation_removal_data();

              /* Reset PL, if configured for */
              (void)psu_ps_pl_reset_config_data();

              /**
              * Fsbl hook after bit stream download
              */
              Status = XFsbl_HookAfterBSDownload();
              if (Status != XFSBL_SUCCESS)
              {
                     Status = XFSBL_ERROR_HOOK_AFTER_BITSTREAM_DOWNLOAD;
                     XFsbl_Printf(DEBUG_GENERAL,
                     "XFSBL_ERROR_HOOK_AFTER_BITSTREAM_DOWNLOAD\r\n");
                     goto END;
              }
       }
#endif

	......

}

在调试时，有些工程师希望FSBL不加载FPGA的bit文件，由Vivado加载FPGA的bit文件。但是Vivado加载FPGA的bit文件后，不会打开PS和PL之间的接口和信号线。这种情况下，建议在FSBL里强制开放MPSoC的PS-PL接口。可以在Xfsbl_handoff.c里屏蔽XFsbl_Handoff()中的行“if (FsblInstancePtr->ResetReason == XFSBL_PS_ONLY_RESET)”，也会执行)psu_ps_pl_isolation_removal_data()和psu_ps_pl_reset_config_data()操作，强制开放MPSoC的PS-PL接口。

u32 XFsbl_Handoff (const XFsblPs * FsblInstancePtr, u32 PartitionNum, u32 EarlyHandoff)
{

	......
	
       //if (FsblInstancePtr->ResetReason == XFSBL_PS_ONLY_RESET)
              {
              /**Remove PS-PL isolation to allow u-boot and linux to access PL*/
                     (void)psu_ps_pl_isolation_removal_data();
                     (void)psu_ps_pl_reset_config_data();
              }
			  
	......

}

另外，psu_init.tcl里也有TCL版本的函数psu_ps_pl_isolation_removal_data()和psu_ps_pl_reset_config_data()；在xsct里执行它们，也可以强制开放MPSoC的PS-PL接口。