[U-Boot] Non standard CFI detection tweaks

[Rogan Dawes <rogan@dawes.za.net>]

On 2010/07/19 11:34 AM, Stefan Roese wrote:
> Hi Rogan,

Hi Stefan,

Thanks for responding.

> On Tuesday 13 July 2010 22:00:37 Rogan Dawes wrote:
>> I'm trying to add support for my D-Link DNS323 (Orion5x-based) to
>> U-Boot, building on the efforts of Albert Aribaud.
>>
>> One place where I am struggling is with the detection of the flash chip.
>>
>> The flash part is a 8 MB Spansion S29GL064M90TFIR4, and the data sheet
>> can be found at:
>>
>> http://www.spansion.com/Support/Datasheets/s29gl-m_00_b8_e.pdf
>>
>> It says:
>>> This device enters the CFI Query mode when the system writes the CFI
>>> Query command, 98h, to address 55h, any time the device is ready to
>>> read array data.
>>
>> Testing this from the command line, however, shows that this is in fact
>> NOT true. In fact, the write needs to occur at aah, not 55h.
>
> This is most likely because of the 8bit width (byte address) vs. 16bit width
> (word address) modes.
>
> How is your FLASH chip connected to your CPU? In 16bit wide mode (which is
> more common)?

I have no idea. Do you have any suggestions how I can find out?

If I do a normal md over the rest of the flash, I do see expected 
strings from the U-Boot "partition", and the kernel and ramdisk 
partitions. i.e. not duplicated or anything like that. Not sure if that 
answers your question at all?

[snip]

>> Do you have any suggestions on the best way to modify cfi_flash.c to
>> detect this chip?
>
> Not right now, sorry.
>
> Cheers,
> Stefan

Any hints on how to get more information to assist in debugging this? 
The CPU is an Orion5x (ARM) part, if that makes any difference.

Rogan