[U-Boot] [PATCH 1/1] NAND Re: mtdparts fails with NAND >= 4GB - Second try

[Aaron Williams]

On Friday, February 11, 2011 11:01:40 pm Albert ARIBAUD wrote:
> Le 12/02/2011 07:42, Aaron Williams a écrit :
> > I've placed the results of the scan below.
> > 
> > The problem is that in 8-bit mode the code that scans the CFI does not
> > follow the specification.
> > 
> > In the specification to read the CFI data you write 0x98 to address 0xAA,
> > not address 0x55 as you do in 16-bit mode. flash_offset_cfi is set to
> > 0x55 which in this case is wrong and won't work. When it tries 16-bit
> > mode then it writes to address 0xAA which causes it to work.
> 
> Let us see the specs, then. The specs I have (admittedly not necessarily
> the latest: I use JESD 68.01, september 1999) state the following:
> 
> "Nonvolatile memory devices are assumed to power up in a read-only
> state. Independent of that assumption, the Query structure contents must
> be able to be read at the specific address locations following a single
> system write cycle where: 1) a 98h Query command code is written to 55h
> address location within the device’s address space (in maximum device
> buswidth), and 2) the device is in any valid read state, such as “Read
> Array” or “Read ID Data”.
> 
> I read "55h address location within the device’s address space (in
> maximum device buswidth" as implying that 0x55 is the only address to
> use but is in device bus terms, and that may mean different CPU
> addresses for different devices types: for x8 devices, one should access
> the byte address 0x55 because the device bus is in bytes, whereas for
> x8/x16 and x16 devices, one should access byte address 0xAA because it
> translates to x16 device bus address 0x55 -- regardless of actual x8 or
> x16 mode.
> 
> Are we in sync here?
> 
> Now it's been a long time since I last looked at my ED Mini V2 Flash,
> but I should be able to dig it up and do a test within one or two hours.
> 
> > -Aaron
> 
> > Here's the results of  the scan:
> Yes, that's what U-boot *CFI code* does, but I'd like to see what very
> basic writes and reads give without any detection logic involved.
> 
> Amicalement,

I'm looking at the Spansion S29GL-N datasheet from 2008. Look at table 10.3 on 
page 53.

http://www.spansion.com/Support/Datasheets/S29GL-N_01_12_e.pdf


-Aaron