uboot修改移植開發(fā)知識梳理.docx

u-boot修改移植開發(fā)知識梳理 /* u-boot裁剪* */board->只留與扳機相關(guān)的文件夾cpu ->只留與扳機相關(guān)的文件夾include->與架構(gòu)無關(guān)的目錄刪除include/configs ->只留架構(gòu)相關(guān)的一個文件include/asm->刪除與架構(gòu)無關(guān)的目錄./->主目錄lib開頭與架構(gòu)無關(guān)的目錄刪除，注意報libfdt留下/* makefile 關(guān)鍵說明* */make ming2440_config流程:make mini2440_config-> mini2440_config:unconfig$(MKCONFIG) $(:_config=) arm arm920t mini2440 risecomm s3c24x0-> mkconfigmini2440_config:unconfig$(MKCONFIG) $(:_config=) arm arm920t mini2440 risecomm s3c24x0/ $(A:patternA=patternB)。意思就是將 A中 patternA格式的字符用patternB來代替?；貧w$(:_config)，/ 代表輸入的參數(shù)，即：mini2440_config，patternA是_config，patternB是空的。說白了就是將mini2440_config的_config去掉。$(MKCONFIG) $(:_config=) arm arm920t mini2440 tekkamanninja s3c24x0 / 查找MKCONFIG，MKCONFIG就是uboot目錄下的那個mkconfig這個文件，這條語句就是：運行mkconfig文件，并傳遞 6個參數(shù)進去mkconfig文件：作用：建立include目錄下的link目錄(asm)，include目錄下創(chuàng)建confg.mk文件，創(chuàng)建config.h文件。APPEND=no# Default: Create new config file BOARD_NAME="" # Name to print in make output TARGETS="" while $# -gt 0 ; do case "$1" in -) shift ; break ; -a) shift ; APPEND=yes ; -n) shift ; BOARD_NAME="$1%_config" ; shift ; -t) shift ; TARGETS="echo $1 | sed s:_: :g $TARGETS" ; shift ; *) break ; esac done / $#是腳本傳遞的參數(shù)的個數(shù)。-gt是>的意思。 $1：第一個參數(shù)。shift：奸殺第一個參數(shù)，/ 將第二參數(shù)變成第一個這段代碼意思 檢查參數(shù)中，有無-a -n -t這樣的參數(shù)，沒有的話直接break。 / 很明顯，makefile傳遞的6個參數(shù)，沒有-a，-t，-n。直接break。 "$BOARD_NAME" | BOARD_NAME="$1"/ ："$BOARD_NAME"表示一個條件，BOARD_NAME != NULL, |表示如果 條件為假 則運行后面的程序。 同時&&表示如果條件為真，則運行后面的程序/ BOARD_NAME等于傳進來的第一個參數(shù)，即BOARD_NAME=mini2440 $# -lt 4 && exit 1/ 小于4個參數(shù)則退出 $# -gt 6 && exit 1/ 大于6個參數(shù)則退出if "$ARCH" -a "$ARCH" != "$2" ; then/ 判斷ARCH變量值是否為BULL ，-a是and的意思，并且 ARCH！= $2echo "Failed: $ARCH=$ARCH, should be $2 for $BOARD_NAME" 1>&2 exit 1 fi echo "Configuring for $BOARD_NAME board." / 建立 asm連接/ Create link to architecture specific headers/ if "$SRCTREE" != "$OBJTREE" ; then/都為null，相等，所以運行else后面mkdir -p $OBJTREE/includemkdir -p $OBJTREE/include2cd $OBJTREE/include2rm -f asmln -s $SRCTREE/include/asm-$2 asmLNPREFIX="././include2/asm/"cd ./includerm -rf asm-$2rm -f asmmkdir asm-$2ln -s asm-$2 asmelsecd ./includerm -f asmln -s asm-$2 asmfirm -f asm-$2/archif -z "$6" -o "$6" = "NULL" ; then/ -z的意思是判斷字符串是否為"" -o是或的意思, 判斷語句意思是$6="" 或者$6=NULL ln -s $LNPREFIXarch-$3 asm-$2/archelseln -s $LNPREFIXarch-$6 asm-$2/arch/ asm-arm下建立連接文件arch，link到arch-s3c24x0fiif "$2" = "arm" ; thenrm -f asm-$2/procln -s $LNPREFIXproc-armv asm-$2/procfi# 把芯片信息輸出到config.mk文件中# Create include file for Make#echo "ARCH = $2" > config.mkecho "CPU = $3" >> config.mkecho "BOARD = $4" >> config.mk "$5" && "$5" != "NULL" && echo "VENDOR = $5" >> config.mk "$6" && "$6" != "NULL" && echo "SOC = $6" >> config.mk# Assign board directory to BOARDIR variableif -z "$5" -o "$5" = "NULL" ; thenBOARDDIR=$4elseBOARDDIR=$5/$4fi/* u-boot支持go命令的方法* 在cmd_boot.c文件中（沒有就自己創(chuàng)建）增加以下內(nèi)容*/* 1、添加call_linux函數(shù)*/void call_linux(long a0, long a1, long a2)_asm_( " mov r1, #0n" " mov r1, #7 << 5n" /* 8 segments */ "1: orr r3, r1, #63 << 26n" /* 64 entries */ "2: mcr p15, 0, r3, c7, c14, 2n" /* clean & invalidate D index */ " subs r3, r3, #1 << 26n" " bcs 2bn" /* entries 64 to 0 */ " subs r1, r1, #1 << 5n" " bcs 1bn" /* segments 7 to 0 */ " mcr p15, 0, r1, c7, c5, 0n" /* invalidate I cache */ " mcr p15, 0, r1, c7, c10, 4n" /* drain WB */); _asm_("mov r0, #0n""mcr p15, 0, r0, c7, c10, 4n" /* drain WB */"mcr p15, 0, r0, c8, c7, 0n" /* invalidate I & D TLBs */);/ 以上的內(nèi)容可以不要/ r0、r1、r2三個寄存器的參數(shù)是傳遞到內(nèi)核head.S文件中，r0:0，r1:體系結(jié)構(gòu)號，r2地址_asm_("mov r0, %0n"/ 獲取0號，也就是第一個（a0）的數(shù)據(jù)"mov r1, #0x0c1n"/ 查芯片相關(guān)資料，mini2440的為 1999"mov r2, %2n"/ 啟動地址 mini2440=0x30008000"mov ip, #0n""mcr p15, 0, ip, c13, c0, 0n" /* zero PID */"mcr p15, 0, ip, c7, c7, 0n" /* invalidate I,D caches */"mcr p15, 0, ip, c7, c10, 4n" /* drain write buffer */ "mcr p15, 0, ip, c8, c7, 0n" /* invalidate I,D TLBs */"mrc p15, 0, ip, c1, c0, 0n" /* get control register */"bic ip, ip, #0x0001n" /* disable MMU */"mcr p15, 0, ip, c1, c0, 0n" /* write control register */"mov pc, r2n""nopn""nopn": /* no outpus */: "r" (a0), "r" (a1), "r" (a2);/*2、添加setup_linux_param函數(shù)*/static void setup_linux_param(ulong param_base) struct param_struct *params = (struct param_struct *)param_base; char *linux_cmd; / 獲取bootargs參數(shù)linux_cmd = getenv("bootargs");memset(params, 0, sizeof(struct param_struct); params->u1.s.page_size = 0x00001000;/ DDR的頁大小params->u1.s.nr_pages = (0x04000000 >> 12);/ 頁數(shù)/* set linux command line */memcpy(params->commandline, linux_cmd, strlen(linux_cmd) + 1);/* u-boot中MAC地址設(shè)置及往內(nèi)核中傳遞* */1.解決uboot命令行中不能設(shè)置ethaddr的問題，經(jīng)常會提示:Cant overwrite "ethaddr"：common/cmd_nvedit.c中函數(shù)_do_setenv中找到189 #ifndef CONFIG_ENV_OVERWRITE190191 /*192 * Ethernet Address and serial# can be set only once,193 * ver is readonly.194 */195 #ifdef CONFIG_HAS_UID196 /* Allow serial# forced overwrite with 0xdeaf4add flag */197 if ( (strcmp (name, "serial#") = 0) && (flag != 0xdeaf4add) |198 #else199 if ( (strcmp (name, "serial#") = 0) |200 #endif201 (strcmp (name, "ethaddr") = 0)202203 #if defined(CONFIG_OVERWRITE_ETHADDR_ONCE) && defined(CONFIG_ETHADDR)204 && (strcmp (char *)env_get_addr(oldval),MK_STR(CONFIG_ETHADDR) != 0)205 #endif /* CONFIG_OVERWRITE_ETHADDR_ONCE && CONFIG_ETHADDR */206 ) ) 207 printf ("Cant overwrite "%s"n", name);208 return 1;209 210 #endif把201行替換成 (0 即可；2.為了讓uboot命令行中設(shè)置的參數(shù)ethaddr傳遞到內(nèi)核，必須修改uboot和linux內(nèi)核兩個地方：（1）uboot修改 ： lib_arm/armlinux.c在 247 #ifdef CONFIG_CMDLINE_TAG248 setup_commandline_tag (bd, commandline);下面添加如下語句：char *buf1 = malloc(1024);sprintf(buf1, "%s mac=%s", getenv ("bootargs"), getenv ("ethaddr");setup_commandline_tag (bd, buf1);（2）linux內(nèi)核修改：drivers/net/davinci_emac.cstatic int emac_eth_setup(void)1899 前面添加：static char davinci_mac_addr_uboot20 = ""1887 static int _init param_mac_setup(char *str)1888 1889 strncpy (davinci_mac_addr_uboot, str, sizeof(davinci_mac_addr_uboot);1890 1891 _setup("mac=", param_mac_setup);并在函數(shù)emac_eth_setup內(nèi)部語句printk("TI DaVinci EMAC: MAC address is %sn", emac_eth_string);前面添加：strncpy(ema