X-008-UBOOT-支持命令行(Bubblegum-96平台)
1. 前言
经过前面文章的铺垫，u-boot command line的支持已经成了一个顺理成章的事情了。因此，本文没有太多技术细节，仅仅记录支持命令行的实现过程，权当“X Project” “【任务2】启动到u-boot command line”的一个完结。
2. 支持命令行的过程
由“X-007-UBOOT-DDR的初始化(Bubblegum-96平台)”的描述可知，我们已经成功初始化DDR，并将u-boot放到DDR中执行，基于该成果，我们进一步调试命令行功能。
2.1 修改版型的配置头文件，将u-boot的DEBUG功能打开，以便得到更多的打印信息
pengo@ubuntu:~/work/xprj/u-boot$ git diff
diff –git a/include/configs/bubblegum.h b/include/configs/bubblegum.h
index 6ee4227..5f22528 100644
— a/include/configs/bubblegum.h
+++ b/include/configs/bubblegum.h
@@ -10,7 +10,7 @@
#ifndef __BUBBLEGUM_H
#define __BUBBLEGUM_H-#define DEBUGX
+#define DEBUG
2.2 根据“X-007-UBOOT-DDR的初始化(Bubblegum-96平台)”所提示的步骤，运行u-boot，得到如下的错误信息。
initcall: 0000000011003180
U-Boot code: 11000000 -> 11014E30 BSS: -> 11014F38
initcall: 0000000011002fc8
initcall: 000000001100321c
DRAM: initcall: 0000000011002834
dram_init
dram_init OK
initcall: 0000000011003484
Monitor len: 00014F38
Ram size: FFFFFFFF80000000
Ram top: FFFFFFFF80000000
initcall: 0000000011002ff8
initcall: 00000000110031b4
TLB table from ffffffff7fff0000 to ffffffff7fff6000
initcall: 000000001100300c
initcall: 0000000011003130
Reserving 83k for U-Boot at: ffffffff7ffdb000
initcall: 00000000110030fc
Reserving 24k for malloc() at: ffffffff7ffd5000
initcall: 0000000011003354
“Synchronous Abort” handler, esr 0x96000040
ELR: 1100b684
LR: 11003384
x0 : ffffffff7ffd4f68 x1 : 0000000000000000
x2 : 0000000000000098 x3 : 0000000000000000
x4 : 0000000000000000 x5 : 0000000000000098
x6 : 0000000000000000 x7 : 0000000000000004
x8 : 0000000000000031 x9 : 0000000000000000
x10: 000000000000000f x11: 000000000007f468
x12: 000000001100d0d8 x13: 000000000000003c
x14: 0000000000000001 x15: 0000000000000008
x16: 0000000000000008 x17: 0000000000000000
x18: 000000000007f990 x19: 0000000011011c70
x20: 0000000011011ba0 x21: 0000000000000000
x22: 0000000011011286 x23: 000000001101185b
x24: 0000000011011293 x25: 0000000080000000
x26: 0000000000000010 x27: 0000002000000000
x28: 000000000000000c x29: 000000000007f930
Resetting CPU …
resetting …
2.3 分析错误信息
由上面黄色位置的信息可以推测，应该是reserve_malloc后面的那个init call出问题了，查一下代码：
#ifndef CONFIG_SPL_BUILD
reserve_malloc,
reserve_board,
#endif
reserve_malloc后面的函数是reserve_board：
/* (permanently) allocate a Board Info struct */
static int reserve_board(void)
{
if (!gd->bd) {
gd->start_addr_sp -= sizeof(bd_t);
gd->bd = (bd_t *)map_sysmem(gd->start_addr_sp, sizeof(bd_t));
memset(gd->bd, ‘\0’, sizeof(bd_t));
debug(“Reserving %zu Bytes for Board Info at: %08lx\n”,
sizeof(bd_t), gd->start_addr_sp);
}
return 0;
}
start_addr_sp不对？再看一下上面的日志输出：
Ram size: FFFFFFFF80000000
Ram top: FFFFFFFF80000000
RAM size不对？回忆一下编译过程，有个编译错误：
/home/pengo/work/xprj/u-boot/board/actions/bubblegum/board.c:136:33: warning: integer overflow in expression [-Woverflow]
代码136行对ram_size的赋值如下：
gd->ram_size = 2 * 1024 * 1024 * 1024; /* 2GB, TODO */
会溢出？先不纠结，先把这个问题修复再说。
2.4 修改ram_size的赋值，避免溢出
diff –git a/board/actions/bubblegum/board.c b/board/actions/bubblegum/board.c
index 81472a4..ea6fddc 100755
— a/board/actions/bubblegum/board.c
+++ b/board/actions/bubblegum/board.c
@@ -133,7 +133,7 @@ int dram_init(void)/* no need do dram init in here, we have done it in SPL */
- gd->ram_size = 2 * 1024 * 1024 * 1024; /* 2GB, TODO */
- gd->ram_size = CONFIG_SYS_SDRAM_SIZE;
printf(“dram_init OK\n”);
return 0;diff –git a/include/configs/bubblegum.h b/include/configs/bubblegum.h
/*
* u-boot SPL definitions, which is resided in SRAM
@@ -33,6 +33,8 @@
#define CONFIG_SYS_SDRAM_BASE 0x0
#define CONFIG_NR_DRAM_BANKS 1+#define CONFIG_SYS_SDRAM_SIZE 0x3FFFFFFF
+
暂时使用一个安全的值，后面再完善。编译重新运行后，出现如下的输出：
…
Initial value for argc=3
Final value for argc=3
initcall: 00000000110024c4 (relocated to 000000003ffdd4c4)
initcall: 00000000110035d0 (relocated to 000000003ffde5d0)
initcall: 00000000110035c0 (relocated to 000000003ffde5c0)
fdtdec_get_config_string: bootcmd
fdtdec_get_config_int: bootsecureU-Boot command line is disabled. Please enable CONFIG_CMDLINE
No CLI available
resetting …
OK，一切正常了，只不过由于没有定义CONFIG_CMDLINE，无法进入命令行。打开相应的配置即可。
2.5 配置命令行功能
配置u-boot，开启命令行有关的配置项包括：
Command line interface —>
[*] Support U-Boot commands
([xprj]# ) Shell prompt
Info commands —>
[*] bdinfo
[*] coninfo
修改后的配置文件为：
pengo@ubuntu:~/work/xprj/u-boot$ git diff configs/bubblegum_defconfig
diff –git a/configs/bubblegum_defconfig b/configs/bubblegum_defconfig
index 85a488d..bc0c5f7 100644
— a/configs/bubblegum_defconfig
+++ b/configs/bubblegum_defconfig
@@ -198,8 +198,9 @@ CONFIG_BOOTSTAGE_STASH_SIZE=4096Command line interface
-# CONFIG_CMDLINE is not set
-CONFIG_SYS_PROMPT="=> "
+CONFIG_CMDLINE=y
+# CONFIG_HUSH_PARSER is not set
+CONFIG_SYS_PROMPT="[xprj]# "Autoboot options
@@ -213,8 +214,8 @@ CONFIG_SYS_PROMPT="=> "
Info commands
-# CONFIG_CMD_BDI is not set
-# CONFIG_CMD_CONSOLE is not set
+CONFIG_CMD_BDI=y
+CONFIG_CMD_CONSOLE=yCONFIG_CMD_CPU is not set
CONFIG_CMD_LICENSE is not set
再次编译并运行u-boot，OK了，如下：
[xprj]# help
? - alias for ‘help’
bdinfo - print Board Info structure
coninfo - print console devices and information
dm - Driver model low level access
env - environment handling commands
help - print command description/usage
printenv- print environment variables
reset - Perform RESET of the CPU
setenv - set environment variables
version - print monitor, compiler and linker version[xprj]# bdinfo
arch_number = 0x00000000
boot_params = 0x00000000
DRAM bank = 0x00000000
-> start = 0x00000000
-> size = 0x3FFFFFFF
baudrate = 115200 bps
TLB addr = 0x3FFF0000
relocaddr = 0x3FFD8000
reloc off = 0x2EFD8000
irq_sp = 0x3FFD0BD0
sp start = 0x3FFD0BD0
以上改动，可参考如下patch：
https://github.com/wowotechX/u-boot/commit/7cc2bd4716bb095925eb6e2c3e43cef157cf40d4
原创文章，转发请注明出处。蜗窝科技，www.wowotech.net。
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