Re: Serial flash memory support

[Hinko Kocevar <hinko.kocevar@cetrtapot.si>]

Damian Slee wrote:
> Jffs2 does support atmel serial dataflash, as far as the driver for spi,
> that is more hardware dependent.   They recently changed the conditional 
> compiles to be CONFIG_JFFS2_FS_WRITEBUFFER for nand and dataflash.
> 
> BTW JFFS2 takes ages to do the startup scan of the flash with the 528 or
> 1056 block size of the dataflash.

Our serial flash uses 256 byte pages and is forming sectors with them, 
depending on the whole flash size. But I guess that is no case for accessing it 
quicker.

>  I was evalutating the latest cvs JFFS2 last week upon eCos.  I think it
> was about 7 seconds for 64kbytes, with the SPI clocked at 15MHz.

That is too slow for our application.
My conclusion would be that JFFS2 is too much for 'slow' SPI serial flash. I 
guess will just use raw access to the data stored there and achieve maximum 
speed. Can mtd raw access driver/module be used for this purpose or is that 
driver meant for a another stuff?

regards,
hinko k
-- 
..because under Linux "if something is possible in principle,
then it is already implemented or somebody is working on it".

					--LKI