NBOOT Analysis - NBOOT.c (2)

/*
---------------------------------------------------------------
File name: NBOOT.c
Description: Perform Nand Bootloader operation
---------------------------------------------------------------
*/
#include "S3C244x.h"
#include "UART.h"
#include "Global.h"
#include "TOC.h"
#include "Nand.h"
#include "MMU.h"


#define TOC_BLOCK (2) //TOC occupies 2 blocks

#define SECTOR_SIZE 512 //Page size: 512 bytes
#define SECTOR_PER_BLOCK 256 //How many pages does each block contain

/**********************************************************
*File name: ReadNandImageToRam
*Input: unEntry entry point
*Output: WINCE image jump address
         0 is invalid
*Function description: Load WINCE image from NAND FLASH to SDRAM
***********************************************************/
UINT32 ReadNandImageToRam(UINT32 unEntry)
{
   UINT32 unSectorsNeeded;
   UINT32 unSector,unLength;
   UINT32 unRam,i;

   
   PTOC pTOC=(PTOC)0x33F00000;//If TOC type definition is used, no need to assign address by yourself
                                //If PTOC type definition is used, the address given by compiler to pTOC variable is unknown
                                //Therefore, it is necessary to force to assign its address
   NandReadSector(TOC_BLOCK*SECTOR_PER_BLOCK,(UINT8 *)pTOC);//Read the content of the 512th sector and assign it to TOC
   
   if(!TOCIsValid(pTOC))
   {
      DEBUGMSG("\r\nTOC is not valid\r\n");
      return 0;
   }
   DEBUGMSG("\r\nTOC is valid\r\n");
   //Parameter dwEntry defines the entry mode, whether to directly enter the WinCE kernel or start Eboot
   if(!(pTOC->id[unEntry].dwImageType &IMAGE_TYPE_RAMIMAGE))
   {
      return 0;
   }
   
   DEBUGMSG("\r\nImage is RamImage\r\n");
   
   unSectorsNeeded= pTOC->id[unEntry].dwTtlSectors; //Total number of sectors occupied by the image
   unRam=VIRTUAL_TO_PHYSICAL(pTOC->id[unEntry].dwLoadAddress);//Virtual address converted to physical address
   
   DEBUGMSGEx("\r\nSectors Total=",pTOC->id[unEntry].dwTtlSectors ,10);
   DEBUGMSGEx("\r\nVirtual Load Address =",pTOC->id[unEntry].dwLoadAddress,16);
   DEBUGMSGEx("\r\nPhysical Load Address =",unRam,16);
   
   i=0;
   
   while(unSectorsNeeded && i    {
       unSector = pTOC->id[unEntry].sgList[i].dwSector;
       unLength = pTOC->id[unEntry].sgList[i].dwLength;  
       
       while(unLength)
       {
         if(unSector % SECTOR_PER_BLOCK == 0)//256页检查一次坏块
         {
           if(!NandCheckBadBlock(unSector/SECTOR_PER_BLOCK))
           {
              unSector+=SECTOR_PER_BLOCK;//Bad block exists
             
              continue;//Do not perform the following operation
           }
           
           DEBUGMSG(".");
         }
         
         if(!NandReadSector(unSector,(UINT8 *)unRam))
         {
            DEBUGMSG("\r\nCan't Load WINCE Image\r\n");
            while(1);
         }
         
         unSector++;
         unLength--;
         
         unRam+=SECTOR_SIZE;
       }  
       
       unSectorsNeeded-=pTOC->id[unEntry].sgList[i].dwLength;    
       i++;

   }
 
   return (pTOC->id[unEntry].dwJumpAddress?VIRTUAL_TO_PHYSICAL(pTOC->id[unEntry].dwJumpAddress) ://获取加载镜像完成后的跳转地址
                                           VIRTUAL_TO_PHYSICAL(pTOC->id[unEntry].dwLoadAddress));
}

void PORTInit(void)
{

   rGPACON = 0x7fffff;
   rGPDCON = 0xaaaaaaaa;      
   rGPDUP  = 0xffff;     // The pull up function is disabled GPD[15:0]
   rGPECON = 0xaaaaaaaa;      
   rGPEUP  = 0xffff;    

   rGPFUP  = 0xff;    

   rGPGCON = 0xFD000000;
   rGPGUP  = 0xffff;  

   rGPHCON = 0x02faaa;

   rGPHUP  = 0x7ff;  
   
   rEXTINT0 = 0x22222222;    // EINT[7:0]
   rEXTINT1 = 0x22222222;    // EINT[15:8]
   rEXTINT2 = 0x22222222;    // EINT[23:16]
   
}
#define BSP_ARGS_ADDR               0x30020800
#define BSP_ARGS_SIZE               0x800

/*
ARGS内存空间的注解
在WINCE的EBOOT中
ARGS  80028000 00000800 RESERVED
自0x80028000处，大小为0x00000800的空间被命名为ARGS，这个空间类型为
RESERVED，用于保存Bootloader和操作系统之间的共享数据

总之在0x30020800地址处必须要对其进行初始化为0，否则WINCE不能够正常激活
以下选自2440的BSP上的代码。

在BSP中，boot loader和OAL之间有一些数据可以共享
这段数据被存放在(BSP_ARGS *) IMAGE_SHARE_ARGS_UA_START这块内存里。
#define IMAGE_SHARE_ARGS_UA_START      0xA0020000
#define IMAGE_SHARE_ARGS_CA_START      0x80020800
#define IMAGE_SHARE_ARGS_SIZE          0x00000800
可以看出来，IMAGE_SHARE_ARGS_UA_START指向的是虚拟内存中的Uncached段，而IMAGE_SHARE_ARGS_CA_START指向虚拟内存中的Cached段。
我的g_oalAddressTable中这样定义：
DCD    0x80000000, 0x30000000, 64      ; 32 MB DRAM BANK 6
因此，它们分别是指向物理地址0x30020000和0x30020800。

然后看config.bib中，可以看到有这段定义：
; Common RAM areas
   AUD_DMA            80002000  00000800  RESERVED
   SDIO_DMA           80010000  00010000  RESERVED
   ARGS               80020800  00000800  RESERVED
   DBGSER_DMA         80022000  00002000  RESERVED
   SER_DMA            80024000  00002000  RESERVED
   IR_DMA             80026000  00002000  RESERVED
   SLEEP              80028000  00002000  RESERVED
   EDBG               80030000  00020000  RESERVED
   DISPLAY 80100000 00100000 RESERVED  

The physical address 0x30020800 corresponding to ARGS is reserved for IMAGE_SHARE_ARGS_CA_START. _BSPArgs  Memory\r\n" ); BufClr( (
char*)  BSP_ARGS_ADDR,  BSP_ARGS_SIZE); //The address and length of pBSPArgs need to be determined according to the BSP package DEBUGMSG("\r\nLoading BSPArgs Memory\r\n"  ); //The IO port must be initialized, otherwise the serial port cannot work properly  UARTInit(S3C2440PCLK,115200);  NandInit();  DEBUGMSGEx("\r\n\r\nPhysical BSPArgs Address = ",BSP_ARGS_ADDR,16);  DEBUGMSGEx("\r\nBSPArgs Size = ",BSP_ARGS_SIZE,16);  DEBUGMSG("\r\nClearing BSPArgs Memory\r\n");  BufClr((char*)BSP_ARGS_ADDR, BSP_ARGS_SIZE); //The address and length of pBSPArgs need to be determined according to the BSP package  DEBUGMSG("\r\nLoading WINCE\r\n");  RunWINCE=(void(*)(void))ReadNandImageToRam(1);  DEBUGMSGEx("\r\nPhysical Jump Address =",(UINT32)RunWINCE,16);  DEBUGMSGEx("\r\n Virtual Jump Address =",PHYSICAL_TO_VIRTUAL((UINT32)RunWINCE),16);  if(Run WINCE)  {     DEBUGMSG("\r\nLoad WINCE Successfully\r\n");     RunWINCE();  }  while(1);  return 0; }