This is a patch that alters the jffs2 code to work on flash devices that is not directly memory mapped without the need to copy the whole flash to RAM.

It is not ready for inclusion and I do not think I will push it as it was quite a bit slower than I expected. It also needs a little more cleanup.

A callback function is added to struct part_info that works like memcpy and is the thing actually reading the flash. The offset member is gone and the jffs2 code always uses 0 as the start address for the filesystem. It is up to the callback function to remap that into something useful.

This code however uses less memory than copying the flash to ram but it is slower. jffs2_scan_empty() could use some speedup but even in situations when that one is not taking mush time this is slower by a factor of 2-3. It's only faster if you happens to have ridiculously slow flash.

I'm going on vacation and is not going to work more on this so if someone wants this added to u-boot you have to fix a proper patch yourself.