Re: ST flashes

[Rick Adams <rgadams@cox.net>]

On Thursday 03 February 2005 02:56 am, linux-mtd-request@lists.infradead.org 
wrote:

>Im using 2.4.19-rmk7-pxa1 ... i know its really old and all 
>that ... but i have no options right now...
>but anyway..
<Here's my problem.
>I have two pxa 255 boards , one with ST flash and one with AMD.
>I configured them to use the lubbock flash driver , and made one 
>partition for jffs2.

>But on the ST , the moment you power down the board ! , the next time , 
>it only mounts , but doesnt
>let me perform any fops. I keep getting I/O errors..for only write 
>operations... read works , coz i could ls in the partition.
>It also doesnt let me format the partition.


Hi Ashwin

What's the part number of the Intel flash, is it a J or K version? The part 
number will look like 28FnnnJ3 where nnn is the size or 28FnnnKvv where nnn 
is size an vv is voltage. These are the part numbers for the TSOP package, 
for the BGA package the first part will be different but will have the J or K 
designation. The J or K designation is the only thing that matters for this 
discussion the rest of the number isn't important. Intel is obsoleting the J 
part and replacing it with the K part. The version of the kernel and the 
Lubbock board were built with J parts (before the K was around). The K is 
"almost" identical to the J. One important difference is the the K part has 
all it's sectors locked at power up and the J has all it's sectors unlocked. 
If you have a driver written for the J and a board with a K part then this 
could lead to the exact problem you talked about.

If this is your situation there are two possible fixes. One is to get a driver 
that understands how to talk to a K, or modify the boot or initialization 
code to unlock all the sector of the K at power up, and then it will function 
exactly like a J. The other main feature the K has is the ability to burst 
read. This will improve some flash operations if the processor supports DMA 
from flash and you modify the boot or initialization code to enable this 
mode. I know the ARM9 core supports it, I don't know offhand if the xScale 
does. Anyhow the point is that the J driver lack of burst mode support only 
has a performance implication and no functional one. The easiest thing is to 
just unlock all flash sectors of the K at power up and use the J driver.

If this isn't your situation (you don't have K parts) then never mind.
-- 
Rick Adams
rick@theptrgroup.com