從u-boot傳bootargs給kernel

1. rebuild u-boot with CONFIG_CMDLINE_TAG defined in include/configs/XXX.h
2. in u-boot:

setenv bootargs xxx=xxx;

Refer to uImage + u-boot的啟動方式 任一方法，用go的不行

setenv flashaddr 10040000;setenv kfile uImage; setenv ramaddr 1500000;tftp $(ramaddr) $(kfile); bootm $(ramaddr);

結果

Star Dorado2 # setenv bootargs xxx=xxx;
Star Dorado2 # setenv flashaddr 10040000;setenv kfile uImage; setenv
ramaddr 1500000;tftp $(ramaddr) $(kfile); bootm $(ramaddr);
config VSC7385
MAC0 PHY Link Status : UP!
INIT VSC8601
VSC8601 Type B Chip
TFTP from server 172.20.5.185; our IP address is 172.20.150.151
Filename 'uImage'.
Load address: 0x1500000
Loading: #################################################################
#################################################################
#################################################################
#################################################################
###################################################
done
Bytes transferred = 1590076 (18433c hex)
## Booting image at 01500000 ...
Image Name: Linux-2.6.16-star
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 1590012 Bytes = 1.5 MB
Load Address: 01500000
Entry Point: 01500040
Verifying Checksum ... OK
XIP Kernel Image ... OK

Starting kernel ...

Uncompressing
Linux................................................................................................ done, booting the kernel.
Linux version 2.6.16-star (root@test-laptop) (gcc version 3.4.6) #7 Tue Jun
3 14:41:53 CST 2008
CPU: FA526id(wb) [66015261] revision 1 (ARMv4)
Machine: STAR STR9100
Memory policy: ECC disabled, Data cache writeback
CPU0: D VIVT write-back cache
CPU0: I cache: 16384 bytes, associativity 2, 16 byte lines, 512 sets
CPU0: D cache: 16384 bytes, associativity 2, 16 byte lines, 512 sets
CPU clock at 250MHz
AHB clock at 125MHz
APB clock at 62MHz
Enable I-ScratchPad Address Start : c002c000
Built 1 zonelists
Kernel command line: xxx=xxx
(..............................................)

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转载：非常不错的u-boot ppt
http://blog.chinaunix.net/u/22617/showart_466018.html

bootm命令浅析
http://blog.chinaunix.net/u1/47239/showart_377972.html
http://blog.csdn.net/menuconfig/archive/2008/04/09/2270429.aspx
http://www.sudu.cn/info/html/edu/linux/20070102/291441.html

使用initrd文件系统 U-boot引导Linux方法
http://linux.chinaitlab.com/administer/753535.html

bootm 0x100000 0x240000
（其中：0x100000是linux内核在flash中的地址，0x240000是initrd在flash中的地
址）

setenv bootargs console=ttyS0,115200n8 root=/dev/ram rw mem=32M
当u-boot使用上面的设置时，能够正常引导linux加载initrd ！

http://www.hhcn.com/cgi-bin/topic.cgi?forum=3&topic=735
14.3.5. Linux Kernel Ignores my bootargs

Question:
Why doesn't the kernel use the command-line options I set in the "bootargs"
environment variable in U-Boot when I boot my target system?

Answer:
This problem is typical for ARM systems only. The following discussion is
ARM-centric:

First, check to ensure that you have configured your U-Boot build so that
CONFIG_CMDLINE_TAG is enabled. (Other tags like CONFIG_SETUP_MEMORY_TAGS or
CONFIG_INITRD_TAG may be needed, too.) This ensures that u-boot will boot
the kernel with a command-line tag that incorporates the kernel options you
set in the "bootargs" environment variable.

If you have the CONFIG_CMDLINE_TAG option configured, the problem is almost
certainly with your kernel build. You have to instruct the kernel to pick up
the boot tags at a certain address. This is done in the machine descriptor
macros, which are found in the processor start-up C code for your
architecture. For the Intel DBPXA250 "Lubbock" development board, the
machine descriptor macros are located at the bottom of the file
arch/arm/mach-pxa/lubbock.c, and they look like this:

MACHINE_START(LUBBOCK, "Intel DBPXA250 Development Platform")
MAINTAINER("MontaVista Software Inc.")
BOOT_MEM(0xa0000000, 0x40000000, io_p2v(0x40000000))
FIXUP(fixup_lubbock)
MAPIO(lubbock_map_io)
INITIRQ(lubbock_init_irq)
MACHINE_END

The machine descriptor macros for your machine will be located in a similar
file in your kernel source tree. Having located your machine descriptor
macros, the next step is to find out where U-Boot puts the kernel boot tags
in memory for your architecture. On the Lubbock, this address turns out to
be the start of physical RAM plus 0x100, or 0xa0000100. Add the
"BOOT_PARAMS" macro with this address to your machine descriptor macros; the
result should look something like this:

MACHINE_START(LUBBOCK, "Intel DBPXA250 Development Platform")
MAINTAINER("MontaVista Software Inc.")
BOOT_PARAMS(0xa0000100)
BOOT_MEM(0xa0000000, 0x40000000, io_p2v(0x40000000))
FIXUP(fixup_lubbock)
MAPIO(lubbock_map_io)
INITIRQ(lubbock_init_irq)
MACHINE_END

If there is already a BOOT_PARAMS macro in your machine descriptor macros,
modify it so that it has the correct address. Then, rebuild your kernel and
re-install it on your target. Now the kernel should be able to pick up the
kernel options you have set in the "bootargs" environment variable.

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uboot启动zImage(go)和uImage(bootm)分析
http://linux.chinaunix.net/techdoc/install/2009/03/15/1101440.shtml

可见go和bootm差异就是 go只是改写pc值，而bootm传递r0，r1，r2还有bootargs

Linux启动bootargs参数分析（转）
http://hi.baidu.com/sdvch/blog/item/26e20586ef9a8aa66d811978.html

Add customized ATAG in U-Boot and Linux
http://blog.xuite.net/bunny/blog/20594102