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.
Also, the flash address is still 0xff800000, even though the kernel has it as 0xf4000000. I guess this is because only a certain number of address lines are actually connected through to the flash chip, and so the chip can appear in multiple places?
Yes, this could be the case. The flash is most likely "mirrored".
Does that make any more sense? Is it possible that the CFI code in U-Boot doesn't consider the case when bus_width == 2?
As mentioned above, this seems to be a common use-case (even though I don't have such a board at hand right now). Bus-width = 2 (vs. bus-width = 1) shouldn't really matter here. A CPU byte access to the flash address space should translate in one access cycle (8-bit) to the flash device.
Sorry, no real idea whats going wrong without being able to test/debug on this platform.
Cheers, Stefan
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