关于mini2440 mmu

hawkliu83

关于mini2440 mmu [复制链接]

前几天拿到一个mini2440，板子很精致。400M的主频，在跑uCos2的时候，发现速度很慢，可是却不知道为什么。怀疑是cache没有利用起来，可是我对于MMU也不是很明白，有没有点建议？

void MMU_Init(void)
{
    int i,j;
    //========================== IMPORTANT NOTE =========================
    //The current stack and code area can't be re-mapped in this routine.
    //If you want memory map mapped freely, your own sophiscated MMU
    //initialization code is needed.
    //===================================================================

    MMU_DisableDCache();
    MMU_DisableICache();

    //If write-back is used,the DCache should be cleared.
    for(i=0;i<64;i++)
            for(j=0;j<8;j++)
                MMU_CleanInvalidateDCacheIndex((i<<26)|(j<<5));
    MMU_InvalidateICache();
   
    #if 0
    //To complete MMU_Init() fast, Icache may be turned on here.
    MMU_EnableICache();
    #endif
   
    MMU_DisableMMU();
    MMU_InvalidateTLB();

    //MMU_SetMTT(int vaddrStart,int vaddrEnd,int paddrStart,int attr)
    //MMU_SetMTT(0x00000000,0x07f00000,0x00000000,RW_CNB);  //bank0
    MMU_SetMTT(0x00000000,0x03f00000,(int)__ENTRY,RW_CB);  //bank0
    MMU_SetMTT(0x04000000,0x07f00000,0,RW_NCNB);                          //bank0
    MMU_SetMTT(0x08000000,0x0ff00000,0x08000000,RW_CNB);  //bank1
    MMU_SetMTT(0x10000000,0x17f00000,0x10000000,RW_NCNB); //bank2
    MMU_SetMTT(0x18000000,0x1ff00000,0x18000000,RW_NCNB); //bank3
    //MMU_SetMTT(0x20000000,0x27f00000,0x20000000,RW_CB); //bank4
    MMU_SetMTT(0x20000000,0x27f00000,0x20000000,RW_CNB); //bank4 for STRATA Flash
    MMU_SetMTT(0x28000000,0x2ff00000,0x28000000,RW_NCNB); //bank5
    //30f00000->30100000, 31000000->30200000
    MMU_SetMTT(0x30000000,0x30100000,0x30000000,RW_NCNB);          //bank6-1
    MMU_SetMTT(0x30200000,0x33e00000,0x30200000,RW_NCNB); //bank6-2
    //
    MMU_SetMTT(0x33f00000,0x33f00000,0x33f00000,RW_NCNB);   //bank6-3
    MMU_SetMTT(0x38000000,0x3ff00000,0x38000000,RW_NCNB); //bank7
   
    MMU_SetMTT(0x40000000,0x47f00000,0x40000000,RW_NCNB); //SFR
    MMU_SetMTT(0x48000000,0x5af00000,0x48000000,RW_NCNB); //SFR
    MMU_SetMTT(0x5b000000,0x5b000000,0x5b000000,RW_NCNB); //SFR
    MMU_SetMTT(0x5b100000,0xfff00000,0x5b100000,RW_FAULT);//not used

   
    MMU_SetTTBase(_MMUTT_STARTADDRESS);
    MMU_SetDomain(0x55555550|DOMAIN1_ATTR|DOMAIN0_ATTR);
            //DOMAIN1: no_access, DOMAIN0,2~15=client(AP is checked)
    MMU_SetProcessId(0x0);
    MMU_EnableAlignFault();
           
    MMU_EnableMMU();
    MMU_EnableICache();
    MMU_EnableDCache(); //DCache should be turned on after MMU is turned on.
}   


// attr=RW_CB,RW_CNB,RW_NCNB,RW_FAULT
void ChangeRomCacheStatus(int attr)
{
    int i,j;
    MMU_DisableDCache();
    MMU_DisableICache();
    //If write-back is used,the DCache should be cleared.
    for(i=0;i<64;i++)
            for(j=0;j<8;j++)
                MMU_CleanInvalidateDCacheIndex((i<<26)|(j<<5));
    MMU_InvalidateICache();
    MMU_DisableMMU();
    MMU_InvalidateTLB();
    MMU_SetMTT(0x00000000,0x07f00000,0x00000000,attr);        //bank0
    MMU_SetMTT(0x08000000,0x0ff00000,0x08000000,attr);        //bank1
    MMU_EnableMMU();
    MMU_EnableICache();
    MMU_EnableDCache();
}   
   

void MMU_SetMTT(int vaddrStart,int vaddrEnd,int paddrStart,int attr)
{
    volatile U32 *pTT;
    volatile int i,nSec;
    pTT=(U32 *)_MMUTT_STARTADDRESS+(vaddrStart>>20);
    nSec=(vaddrEnd>>20)-(vaddrStart>>20);
    for(i=0;i<=nSec;i++)*pTT++=attr |(((paddrStart>>20)+i)<<20);
}

hilltree

我敢断定和这个绝对没有关系。
——————————————————————
MMU使用不当会导致系统崩溃，而不是慢！

apple2

怎么个速度很慢？ 你用的估计是友善之臂的mini2440,那个uCOS2显示的是RTC（实时时钟）内容。每秒变一次。看上去
当然“很慢”。

suizhihen

不懂mmu~~~

chokee

好像400MHz很多芯片都没有跑到它标称的值上

要不LZ你看看你的时钟

20041143kk

要看时钟是怎样配置的.......

icu

通常,uCOS-II并不需要配置MMU