[U-Boot] about TLB mapping(Powerpc T1024RDB)

[shoulianyu]

Hi,
I'm new to Uboot. Can someone help me.
I went through the tbl_table (in tlb.c) and got puzzled by the following entries:
...
SET_TLB_ENTRY(1, CONFIG_SYS_FLASH_BASE, CONFIG_SYS_FLASH_BASE_PHYS,
               MAS3_SX|MAS3_SR, MAS2_W|MAS2_G,
               0, 2, BOOKE_PAGESZ_256M, 1),
...
 SET_TLB_ENTRY(1, CONFIG_SYS_BMAN_MEM_BASE, CONFIG_SYS_BMAN_MEM_PHYS,
               MAS3_SX|MAS3_SW|MAS3_SR, 0,
               0, 5, BOOKE_PAGESZ_16M, 1),


The first entry  maps 256M space starting at 0xe800_0000, which is  [0xe800_0000, 0xf800_0000) .
The second 16M at  0xf400_0000,which is [0xf400_0000, 0xf500_0000)
the thing I can't understand is how  TLB entries can overlap each other.
Isn't it considered a programming error as pointed out in the E5500Core Ref?


I know I must have got something wrong, but I checked the header files and did the calcs again and again,
still, nothing dawned on me. 


I'm using  Freescale T1024RDB board.


please help!!!