[U-Boot-Users] " Configuring Flash on PPC405ep board"

Stefan Roese sr at denx.de
Fri Sep 23 12:42:48 CEST 2005

Hi Nagi,

On Friday 23 September 2005 12:09, nreddy at netenrich.com wrote:
> I need to know how to configure 8MB Flash on PPC405ep board.
> I already have 4MB flash on PPC405ep board working fine .
> I am using u-boot as my bootloader.

That's good. If not, your mail would be pretty wrong here in this list! ;-)

> Can anybody tell me what are the registers to be configured at Processor
> side(i am new to this register settings) or memory controller side.

If you are lucky, you "only" have to change the EBC (external bus controller) 
setup for the corresponding CS (chip select). Please see e.g. below some 
lines from the bubinga (AMCC 405EP eval board) config file 

/* Memory Bank 0 (Flash/SRAM) initialization                                    
#define CFG_EBC_PB0AP           0x04006000
#define CFG_EBC_PB0CR           0xFFF18000  /* BAS=0xFFF,BS=1MB,BU=R/W,BW=8bit  

To change the size of this CS0 setup, you need to change the BAS field and the 
BS field. E.g. to something like this:

#define CFG_EBC_PB0CR           0xFF8E8000  /* BAS=0xFF8,BS=8MB,BU=R/W,BW=8bit  

But I would suggest that you take a look at the 405EP user's manual to check 
yourself. It's not that complicated.

Now you (hopefully) have the CS setup correctly, but you also have to 
configure/change your flash driver to support this new flash. Do you use the 
common CFI driver? Or a board specific version?

> Please tell me the steps that i need to follow to write my own dirver(i
> may take existing driver as reference).

Best regards,

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