JFFS2 NAND flash support

[David Woodhouse]

gleixner at autronix.de said:
> There's no better to ensure, that erase read and write can coexist at
> the  moment. But you're invited to hack a better solution :)

> I this a new card type ? All chips and card types I know, have maximum
> block  erase times of 20ms.

Disabling bottom halves for 20ms isn't acceptable. The NOR chip drivers get 
this right - or at least attempt to.

--
dwmw2