[U-Boot-Users] Flash configuration

[Alex Zeffertt]

On Thu, 13 Oct 2005 16:27:20 +0100

> Hello u all!
> 
> 	I'm configuring u-boot (for the first time) so that i can have
> 	2 flash eprom chips, in two different banks, for a mpc8272
> 	based board. They are organized the following way:
> 	
> 		BOOT Flash -> starts at 0xFFF00000 and has 512KB of size.
> 		(read-only) Linux Flash -> starts at 0x50000000 and has 64MB
> 		of size. (CFI compatible)
> 
> 	Since CFG_FLASH_BASE is used throughout the u-boot code as a
> 	reference, which one should it be? The boot flash address or
> 	the linux flash address? I'm really confused here... All is
> 	setup so that the processor starts to boot from 0xFFF00000 and
> 	the reset vector set to 0xFFF00100. Should I use the cfi_flash
> 	driver, provided by u-boot? Or should I write a flash.c in my
> 	board directory (this is done already)? Do I have to change
> 	anything when I use the driver?
> 
> 


CFG_FLASH_BASE is the address to which u-boot remaps the flash on CS0.

I assume that by "Linux Flash" you mean a Linux root file system on a
seperate chip.  If so then I think you need to map it (to a different
CS) in u-boot/board/<yourboard>/flash.c.  Then you can use the
"bootcmd" variable to boot the kernel uImage from whereever in this
chip it is.

The bootargs variable will tell the kernel where to find its root file
system.  You will have to write a mapping driver
drivers/mtd/<yourboard>.c so that the kernel knows how to interpret
this.

Alex


> 
> Thanks in advance!
> Filipe
> 
> 
> 
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