Wear-leveling peculiarities

[Ezequiel Garcia]

On 05/26/2015 08:14 AM, Johannes Bauer wrote:
> Am 26.05.2015 12:08, schrieb Richard Weinberger:
> 
>> What flash is this?
>> I should not start dying that early.
> 
> To be honest, I have no idea. The problem is that the CPU is stacked on
> top of the NAND via package-on-package technlogoly. The whole component
> is supplied by a third party (and I've just scanned their documentation,
> which does not give any hints about the origin of the NAND). So I have
> no markings on the package (POP) and no documentation. The only thing I
> do have is dmesg:
> 
> omap2-nand driver initializing
> ONFI flash detected
> NAND device: Manufacturer ID: 0x20, Chip ID: 0xaa (ST Micro NAND 256MiB
> 1,8V 8-bit)
> 

According to this:

http://www.linux-mtd.infradead.org/nand-data/nanddata.html

0x20 0xaa is the ID of Numonyx/ST NAND02GXXX. Searching for the specs it
seems the device is SLC, so it's kind of unexpected that the default WL
value was wrong.

> Maybe there's a way to talk to the NAND directly and get some more
> identification, but I don't know how. Any hints? I'd happily provide clues.
> 

The ONFI specs talk about that (a quick "onfi spec pdf" search will do).
The ONFI specifies a paramter page which contains all the information
about the device (5.7.1. Parameter Page Data Structure Definition).

Keep us updated if you find why the flashes are dying :)
-- 
Ezequiel Garcia, VanguardiaSur
www.vanguardiasur.com.ar