[U-Boot-Users] u-boot CFI driver question

shafer sh.workmail at gmail.com
Wed Oct 24 21:58:28 CEST 2007


I am attempting to bring up a board with u-boot. I've so far been able to get
u-boot far enough along to get to the main prompt. I am having an issue
reading from and writing to the FLASH memory in my setup. For simplicity
sake my setup consists of an ARM920T processor, EEPROM (AM29040B) and 2
FLASH devices (S29GL256N...). U-boot resides in the EEPROM and I am able to
read/write to the EEPROM.

My non-EEPROM FLASH configuration consists of two devices. Both devices have
23 address pins and 16 data pins. I have routed the 23 address pins of the
ARM to both FLASH devices. However, I have routed the ARM’s lower 16 data
pins to one device and its upper 16 data pins to the second device. On paper
this should give me 8 Meg locations of 32 bits for a total of 32 Megs of
FLASH. 

I have compiled u-boot to include the CFI driver. I am pretty certain that I
have setup the ARM through u-boot to use the proper chip select and
address/data bus. I believe this because when I issue an erase command from
the u-boot prompt I can see the correct chip select toggle and I see the
correct address and data pins wiggling. 

My issue seems to be when I try to read/write to the FLAHS devices. For
example, when I issue the erase command u-boot spits back an error message.
Unfortunately, I am not able to tell you the exact error message at the
moment and I cannot remember the exact phrase. 

Error message aside I suspect that I am have a problem because I have not
informed u-boot of this configuration. So my questions are:

1) Does u-boot inherently support a setup with a 32 bit data bus split
across two devices?
2) If so can someone point me to an example configuration file in u-boot to
get the cfi driver properly configured?
3) If not, has someone patched u-boot to handle this configuration?

Thanks for the help in advance.

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