Stefan Roese wrote:
Hi Rogan,
On Thursday 12 August 2010 14:07:03 Rogan Dawes wrote:
I found the following configuration snippet for OpenOCD for the DNS323 at http://wiki.dns323.info/hardware:jtag:
# driver addr size chip_width bus_width options flash bank cfi 0xff800000 0x800000 1 2 0
It seems that the key here is that the bus_width is set to 2, even though the chip_width is only 1.
Seems not to be so uncommon: 8bit device on a 16bit external bus.
It is mostly likely a 8/16 bit wide device in 8 bit mode on an 8 bit external bus. Then all CFI data appears twice.
Reason: the chip presents CFI data correctly (from the flash point of view) in 16 bit mode (flash A0 connected to CPU A1). If connected in 8 bit mode (flash A0 connected to CPU A1, flash A-1 connected to CPU A0) it still presents the data at the same adresses but the CFI driver gets misled because its told to try for 8 bit wide flash.
Since that was an issue long ago, I made the board/emk/common/flash.c (CFI) driver. Anyone is welcome to add that special handling for 16 bit flash connected in 8 bit mode to the general CFI driver :)
Best Regards, Reinhard