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6678 4GB DDR3空间访问问题



TI的专家你好,目前使用的6678自己投的板子,硬件DDR3由前期的2GB升级到了目前的4GB,使用MPAX配置地址映射有两个疑问想请教下:

1:   后2GB的DDR3地址该如何映射

   逻辑地址                                物理地址                             
0000_0000 – 7FFF_FFFF -》 0:0000_0000 – 0:7FFF_FFFF                                             C6678  MPAX上电默认值的配置
8000_0000 – FFFF_FFFF -》 8:0000_0000 – 8:7FFF_FFFF ----前2GB DDR3  空间        C6678  MPAX上电默认值的配置
????_???? –   ????????   》 8:8000_0000 – 8:FFFF_FFFF ----后2GB DDR3  空间        该如何配置  XMPAXH      XMPAXL

逻辑地址0000_0000-FFFF_FFFF被用完了,请问具体到MPAX配置 ,代码中XMPAXH的BADDR和XMPAXL的RADDR该怎么填写?

 示例代码:

XMC_regs->XMPAX[1].XMPAXH =
  ((0x80000000)&(CSL_XMC_XMPAXH_BADDR_MASK))|
  ((30)<<(CSL_XMC_XMPAXH_SEGSZ_SHIFT));  /*2^(30+1)=2GB*/
 XMC_regs->XMPAX[1].XMPAXL =
  ((0x80000000)&(CSL_XMC_XMPAXL_RADDR_MASK))|
  ((1)<<(CSL_XMC_XMPAXL_SR_SHIFT))|
  ((1)<<(CSL_XMC_XMPAXL_SW_SHIFT))|
  ((0)<<(CSL_XMC_XMPAXL_SX_SHIFT))|
  ((1)<<(CSL_XMC_XMPAXL_UR_SHIFT))|
  ((1)<<(CSL_XMC_XMPAXL_UW_SHIFT))|
  ((0)<<(CSL_XMC_XMPAXL_UX_SHIFT));

2:映射后如何访问

在对后2GB配置了MPAX后,要是想访问后2GB的DDR3的第一个字节是直接填写具体的物理地址8:8000_0000去访问么?

请TI专家抽空解答下,多谢多谢