[U-Boot] One basic U-boot question

Scott Wood scottwood at freescale.com
Wed Dec 12 22:36:37 CET 2012


On 12/12/2012 02:11:46 AM, Martin Peevski wrote:
>     Hello, I have the following question. It is about the adresses  
> where the U-boot and  Linux Kernel are copyed in the SDRAM from NAND.
> 
>     In my board config file I have:
>     #define CONFIG_SYS_LOAD_ADDR        0x22000000    /* load address  
> */
>     Is that the load address of the U-boot?

No, it's the default address to load the kernel (or other image).  Note  
that this is where the uImage goes, not where the kernel gets  
uncompressed to (which is specified in the uImage header).

U-Boot is loaded near the top of SDRAM (or the portion of SDRAM that  
U-Boot has mapped).

BTW, you should use a subject line that is more specific to your  
question, such as "What is CONFIG_SYS_LOAD_ADDR?" or "Where does the  
kernel get loaded with <command name>?".  "One basic U-Boot question"  
doesn't give any clues to people skimming the list to see if it's the  
sort of question they might have the answer to.

>     Also where is defined the load address of the Kernel because may  
> be I need to leave more free space about the Kernel and RootFS?

CONFIG_SYS_LOAD_ADDR is the default, but you can and should override it  
in the arguments to the command doing the loading.

-Scott


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