VX启动代码.doc

/* bootInit.c - ROM initialization module */

/* Copyright 1989-2002 Wind River Systems, Inc. */
#include "copyright_wrs.h"

/*
modification history
--------------------
05h,26mar02,sbs correcting data section relocation for ROM compressed images
(SPR 73785)
05g,19mar02,dat Removing previous fix for MIPS, no longer needed (72825)
05f,18jan02,dat Don't use loop unrolling for MIPS
05f,22jan02,scm Xscale specific validation added to update cache (to match
updates...)
05e,19dec01,aeg prevented pc-relative addressing on MC680X0.
05d,10dec01,sbs Corrected conditions around call to copyLongs for ROM
resident images.
05c,27nov01,sbs Added new labels, wrs_kernel_data_start and wrs_kernel_data_end
for sdata and edata respectively. Added second copy for data
section of compressed ROM images. Corrected definition for
binArrayEnd. Corrected definition for RESIDENT_DATA.
05b,27nov01,tpw Manually unroll copyLongs and fillLongs.
05a,25oct01,pad Removed definitions of _binArrayStart and _binArrayEnd, now
unnecessary.
04z,03oct01,dee Merge from ColdFire T2.1.0 release
04y,11jan01,scm Xscale specific validation added to update cache, can not assume uncached area....
04x,10jun99,jpd fix error when BOOTCODE_IN_RAM defined (SPR #27775).
04w,13nov98,cdp make Thumb support for ARM CPUs dependent on ARM_THUMB.
04w,10feb99,db Fix to ensure that default bootline gets copied for
standalone and rom-resident images(SPR #21763).
04v,05oct98,jmp doc: cleanup.
04u,17apr98,cdp backed out 04t and made absEntry volatile for ARM.
04t,16apr98,cdp for ARM, make UNCOMPRESS entry point in RAM.
04s,20mar98,cdp make ROM_COPY_SIZE subject to #ifndef.
04r,11nov97,cdp ARM7TDMI_T: force romStart to call entry point in Thumb state.
(SPR# 9716)
04q,14jul97,tam changed remaining references to bfillLong to fillLong.
04p,12feb97,dat Added USER_RESERVED_MEM, SYS_MEM_TOP, SYS_MEM_BOTTOM, SPR 8030
04o,04feb97,ms fixed compiler warning about protoype for bcopyLongs.
04o,28nov96,cdp added ARM support.
04n,03sep96,hdn added the compression support for pc[34]86 BSP.
04m,19aug96,ms added UNCMP_RTN macro to use inflate instead of uncompress
04l,21jun96,jmb long modhist -- deleted entries prior to 1994. SPR #6528
03k,10jun96,tam added rom resident support for PPC architecture.
03j,14may96,dat fixed compiler warnings for copyLongs, fillLongs. SPR #6536
03i,06mar96,tpr changed absEntry to be volatile for PowerPC.
03h,22aug95,hdn added support for I80X86.
03g,14mar95,caf restored mips resident rom support (SPR #3856).
03f,16feb95,jdi doc format change.
03f,23may95,yao define binArrayStart and binArrayEnd for PowerPC
because tools don't prepend "_".
03e,09dec94,caf undid mod 03a, use sdata for resident roms (SPR #3856).
03d,22jun94,caf undid 16-byte alignment portion of mod 03c, below.
03c,14jun94,cd corrected definitions of etext, edata and end.
+caf for R4000 resident ROMs: data starts on 16-byte boundary.
for R4000 uncompressed ROMs: added volatile to absEntry type.
*/

/*
DESCRIPTION
This module provides a generic boot ROM facility. The target-specific
romInit.s module performs the minimal preliminary board initialization and
then jumps to the C routine romStart(). This routine, still executing out
of ROM, copies the first stage of the startup code to a RAM address and
jumps to it. The next stage clears memory and then uncompresses the
remainder of ROM into the final VxWorks ROM image in RAM.

A modified version of the Public Domain \f3zlib\fP library is used to
uncompress the VxWorks boot ROM executable linked with it. Compressing
object code typically achieves over 55% compression, permitting much
larger systems to be burned into ROM. The only expense is the added few
seconds delay while the first two stages complete.

ROM AND RAM MEMORY LAYOUT
Example memory layout for a 1-megabyte board:
.CS
-------------- 0x00100000 = LOCAL_MEM_SIZE = sysMemTop()
| |
| RAM |
| 0 filled |
| |
|------------| = (romInit+ROM_COPY_SIZE) or binArrayStart
| ROM image |
|----------- | 0x00090000 = RAM_HIGH_ADRS
| STACK_SAVE |
|------------|
| | 0x00080000 = 0.5 Megabytes
| |
| |
| 0 filled |
| |
| | 0x00001000 = RAM_ADRS & RAM_LOW_ADRS
| |
| | exc vectors, bp anchor, exc msg, bootline
| |
| |
-------------- 0x00000000 = LOCAL_MEM_LOCAL_ADRS
.CE
.CS
--------------
| ROM |
| | 0xff8xxxxx = binArrayStart
| |
| | 0xff800008 = ROM_TEXT_ADRS
-------------- 0xff800000 = ROM_BASE_ADRS
.CE

SEE ALSO:
inflate(), romInit(), and deflate

AUTHOR
The original compression software for zlib was written by Jean-loup Gailly
and Mark Adler. See the manual pages of inflate and deflate for
more information on their freely available compression software.
*/

#include "vxWorks.h"
#include "sysLib.h"
#include "config.h"
#include "errno.h"
#include "sioLib.h"

#define UNCMP_RTN inflate

#ifndef USER_RESERVED_MEM
# define USER_RESERVED_MEM 0
#endif

/*
* If memory is to be cleared, it will be cleared from SYS_MEM_BOTTOM
* up to (but not including) SYS_MEM_TOP, except for text and data segments.
* The user reserved area is not cleared.
*/

#define SYS_MEM_TOP \
(LOCAL_MEM_LOCAL_ADRS + LOCAL_MEM_SIZE - USER_RESERVED_MEM)

#define SYS_MEM_BOTTOM \
(LOCAL_MEM_LOCAL_ADRS + RESERVED)

#define BINARRAYEND_ROUNDOFF (ROUND_DOWN(binArrayEnd, sizeof(long)))

IMPORT void romInit ();
IMPORT STATUS UNCMP_RTN ();
IMPORT void usrInit ();
IMPORT void sysInitAlt ();
IMPORT void start ();

IMPORT UCHAR binArrayStart []; /* compressed binary image */
IMPORT UCHAR binArrayEnd []; /* end of compressed binary image */
IMPORT char etext []; /* defined by the loader */
IMPORT char end []; /* defined by the loader */
IMPORT UCHAR wrs_kernel_data_start []; /* defined by the loader */
IMPORT UCHAR wrs_kernel_data_end []; /* defined by the loader */

#if ((CPU_FAMILY == MIPS) || (CPU_FAMILY==PPC) || \
(CPU_FAMILY==COLDFIRE))
#define RESIDENT_DATA RAM_DST_ADRS //定义体系结构特殊信息==压缩映象最终重定位的地址
#else
#define RESIDENT_DATA wrs_kernel_data_start
#endif

#ifndef RAM_DST_ADRS /* default uncompress dest. */
#define RAM_DST_ADRS RAM_HIGH_ADRS //压缩映象最终重定位的地址==拷贝引导映象的入口地址
#endif

/* If the boot code is in RAM and the RAM is already initialized,
* clearing the RAM is not necessary. Macro BOOTCODE_IN_RAM is
* used not to clear the RAM.
*/
#ifdef BOOTCODE_IN_RAM /* not to clear RAM */
#undef ROM_TEXT_ADRS
#undef ROM_BASE_ADRS
#define ROM_TEXT_ADRS ((UINT)romInit)
#define ROM_BASE_ADRS ((UINT)romInit) //引导rom的入口地址
#endif /* BOOTCODE_IN_RAM */

/* #if defined (UNCOMPRESS) || defined (ROM_RESIDENT) */
#ifndef ROM_COPY_SIZE
#define ROM_COPY_SIZE (ROM_SIZE - (ROM_TEXT_ADRS - ROM_BASE_ADRS))
#endif
/* #endif*/ /* UNCOMPRESS */

#define ROM_OFFSET(adr) (((UINT)adr - (UINT)romInit) + ROM_TEXT_ADRS) //rom->ram时涉及到计算偏移地址函数,重定位了adr在rom当中的位置;

/* forward declarations */

LOCAL void copyLongs (FAST UINT *source, FAST UINT *destination, UINT nlongs);//拷贝rom->ram函数
#ifndef BOOTCODE_IN_RAM
LOCAL void fillLongs (FAST UINT *buf, UINT nlongs, FAST UINT val);//往ram填零函数
#endif /* BOOTCODE_IN_RAM */
#if (CPU==XSCALE)
int checkLongs (FAST UINT *source, FAST UINT *destination, UINT nlongs);//比较函数
#endif

/****************
*
* romStart - generic ROM initialization
*
* This is the first C code executed after reset.
*
* This routine is called by the assembly start-up code in romInit().
* It clears memory, copies ROM to RAM, and possibly invokes the uncompressor.
* It then jumps to the entry point of the uncompressed object code.
*
* RETURNS: N/A
*/

void romStart
(
FAST int startType /* 启动类型，它的入口参数是startType，是一个启动类型标志，这在后面清内存时会用到*/
)

{
#if ((CPU_FAMILY==SPARC) || (CPU_FAMILY==MIPS) || (CPU_FAMILY==I80X86) \
(CPU_FAMILY==PPC) || (CPU_FAMILY==ARM))
volatile /* to force absolute adressing */
#endif /* (CPU_FAMILY==SPARC) */
FUNCPTR absEntry; /* to avoid PC Relative Jump Subroutine */
//函数指针变量absEntry，它最后指向ursInit()或compressedEntry()函数

#if (CPU_FAMILY==ARM) && (!defined(ROM_RESIDENT)) && !defined(BOOTCODE_IN_RAM)
VOIDFUNCPTR ramfillLongs = fillLongs; /* force call to RAM */
#define fillLongs(a,b,c) ramfillLongs(a,b,c)
#endif /* (CPU_FAMILY==ARM) */

#if (CPU_FAMILY==MC680X0) && !defined(ROM_RESIDENT) && !defined(BOOTCODE_IN_RAM)
volatile VOIDFUNCPTR romcopyLongs = ©Longs; /* force call to ROM */
#define copyLongs romcopyLongs
#endif /* (CPU_FAMILY==MC680X0) */
/*
* Copy from ROM to RAM, minus the compressed image
* if compressed boot ROM which relies on binArray
* appearing last in DATA segment.
*/

#ifdef ROM_RESIDENT
/* If ROM resident code, then copy only data segment
* from ROM to RAM, initialize memory and jump
* to usrInit.
*/
#if (CPU_FAMILY == SPARC)
copyLongs ((UINT *)(etext + 8), (UINT *) RESIDENT_DATA,
#else
copyLongs ((UINT *)etext, (UINT *) RESIDENT_DATA,
#endif
((UINT) wrs_kernel_data_end - (UINT) RESIDENT_DATA) / sizeof (long));

#else /* ROM_RESIDENT */

#ifdef UNCOMPRESS

#if (CPU_FAMILY == MIPS)
/*
* copy text to uncached locations to avoid problems with
* copy back caches
*/
((FUNCPTR)ROM_OFFSETcopyLongs)) (ROM_TEXT_ADRS, (UINT)K0_TO_K1(romInit),
ROM_COPY_SIZE / sizeof (long));
#else /* CPU_FAMILY == MIPS */
((FUNCPTR)ROM_OFFSET(copyLongs)) (ROM_TEXT_ADRS, (UINT)romInit,
ROM_COPY_SIZE / sizeof (long));
#endif /* CPU_FAMILY == MIPS */

#else /* UNCOMPRESS */

#if (CPU_FAMILY == MIPS)
/*
* copy text to uncached locations to avoid problems with
* copy back caches
* copy the entire data segment because there is no way to ensure that
* binArray is the last thing in the data segment because of GP relative
* addressing
*/
((FUNCPTR)ROM_OFFSET(copyLongs)) (ROM_TEXT_ADRS, (UINT)K0_TO_K1(romInit),
((UINT)wrs_kernel_data_end - (UINT)romInit) / sizeof (long));
#else /* CPU_FAMILY == MIPS */
((FUNCPTR)ROM_OFFSET(copyLongs)) (ROM_TEXT_ADRS, (UINT)romInit, //(FUNCPTR)为int (*)()型的函数指针；ROM_OFFSET为rom->ram时涉及到计算偏移地址函数，重定位了copyLongs在rom当中的位置；
//(copyLongs)为拷贝rom->ram函数；ROM_TEXT_ADRS为拷贝内容rom入口地址；(UINT)romInit为ram目标地址
((UINT)binArrayStart - (UINT)romInit)/ sizeof (long)); //非压缩镜像大小，binArrayStart为压缩部分起始地址；
//rom->ram 代码段部分；
((FUNCPTR)ROM_OFFSET(copyLongs))
((UINT *)((UINT)ROM_TEXT_ADRS + ((UINT)BINARRAYEND_ROUNDOFF - //(UINT)BINARRAYEND_ROUNDOFF为ram中压缩部分之后目标地址；
(UINT)romInit)), (UINT *)BINARRAYEND_ROUNDOFF,
((UINT)wrs_kernel_data_end - (UINT)binArrayEnd) / sizeof (long));

#if (CPU==XSCALE)
/* validate coherence, can not assume uncached area... */
((FUNCPTR)ROM_OFFSET(checkLongs))
(ROM_TEXT_ADRS, (UINT)romInit,
((UINT)binArrayStart - (UINT)romInit) / sizeof (long));

((FUNCPTR)ROM_OFFSET(checkLongs))
((UINT *)((UINT)ROM_TEXT_ADRS + ((UINT)BINARRAYEND_ROUNDOFF -
(UINT)romInit)), (UINT *)BINARRAYEND_ROUNDOFF,
((UINT)wrs_kernel_data_end - (UINT)binArrayEnd) / sizeof (long));
#endif
#endif /* CPU_FAMILY == MIPS /

#endif /* UNCOMPRESS */
#endif /* ROM_RESIDENT */

#if (CPU_FAMILY != MIPS) && (!defined (BOOTCODE_IN_RAM))

/* clear all memory if cold booting */

if (startType & BOOT_CLEAR)
{
#ifdef ROM_RESIDENT
/* Clear memory not loaded with text & data.
*
* We are careful about initializing all memory (except
* STACK_SAVE bytes) due to parity error generation (on
* some hardware) at a later stage. This is usually
* caused by read accesses without initialization.
*/
fillLongs ((UINT *)SYS_MEM_BOTTOM,
((UINT) RESIDENT_DATA - STACK_SAVE - (UINT)SYS_MEM_BOTTOM)
/ sizeof(long), 0);
fillLongs (((UINT *) wrs_kernel_data_end),
((UINT)SYS_MEM_TOP - ((UINT) wrs_kernel_data_end)) / sizeof(long), 0);

#else /* ROM_RESIDENT */
fillLongs ((UINT *)(SYS_MEM_BOTTOM),
((UINT)romInit - STACK_SAVE - (UINT)SYS_MEM_BOTTOM) /
sizeof(long), 0); //实现了从SYS_MEM_BOTTOM到STACK_SAVE之前RAM的清零

#if defined (UNCOMPRESS)
fillLongs ((UINT *)((UINT)romInit + ROM_COPY_SIZE),
((UINT)SYS_MEM_TOP - ((UINT)romInit + ROM_COPY_SIZE))
/ sizeof(long), 0);
#else
fillLongs ((UINT )wrs_kernel_data_end, //实现了从数据段到SYS_MEM_TOP的RAM区清零
((UINT)SYS_MEM_TOP - (UINT)wrs_kernel_data_end) / sizeof (long), 0);
#endif /* UNCOMPRESS */
#endif /* ROM_RESIDENT */

/*
* Ensure the boot line is null. This is necessary for those
* targets whose boot line is excluded from cleaning.
*/

*(BOOT_LINE_ADRS) = EOS;
}

#endif /* (CPU_FAMILY != MIPS) && (!defined (BOOTCODE_IN_RAM)) */

/* jump to VxWorks entry point (after uncompressing) */

#if defined (UNCOMPRESS) || defined (ROM_RESIDENT)
#if (CPU_FAMILY == I960)
absEntry = (FUNCPTR)sysInitAlt; /* reinit proc tbl */
#else
absEntry = (FUNCPTR)usrInit; /* on to bootConfig */
#endif /* CPU_FAMILY == I960 */

#else
{
#if (CPU_FAMILY == MIPS)
volatile FUNCPTR absUncompress = (FUNCPTR) UNCMP_RTN;
if ((absUncompress) ((UCHAR *)ROM_OFFSET(binArrayStart),
(UCHAR *)K0_TO_K1(RAM_DST_ADRS),
(int)((UINT)binArrayEnd - (UINT)binArrayStart)) != OK)
#elif (CPU_FAMILY == I80X86) || (CPU_FAMILY == ARM)
volatile FUNCPTR absUncompress = (FUNCPTR) UNCMP_RTN; // UNCMP_RTN为原形函数为int inflate(Byte * src,Byte * dest,int nBytes)
if ((absUncompress) ((UCHAR *)ROM_OFFSET(binArrayStart), //ROM_OFFSET(binArrayStart为压缩文件起始地址，在rom中需要重定向；
(UCHAR *)RAM_DST_ADRS, binArrayEnd - binArrayStart) != OK) //解压缩过程，RAM_DST_ADRS目标地址；

#else
if (UNCMP_RTN ((UCHAR *)ROM_OFFSET(binArrayStart),
(UCHAR *)RAM_DST_ADRS, binArrayEnd - binArrayStart) != OK)
#endif /* (CPU_FAMILY == MIPS) */
return; /* if we return then ROM's will halt */

absEntry = (FUNCPTR)RAM_DST_ADRS; /* compressedEntry () 程序的入口地址就是RAM_DST_ADRS */
}
#endif /* defined UNCOMPRESS || defined ROM_RESIDENT */

#if ((CPU_