My system is based on MPc8544.
I am loading a small standalone program (2KB) from the JFFS2 partition (NOR flash)
My program crashes while it does not crash if loaded from a tftp server.
After investifgation using Codewarrior I noticed that there is a difference between the memory and Dcache content. Some number of words (8 = cache line)) are all zero in Dcache. Hence when jumping the program crashes as I guess the instruction cache is picking the instructions from the Dcache.
When the program is loaded from a tftp server both the cache (in copyback mode) and DDR are set with the same data and therefore the program works. When loaded from a JFFS2 partition, the data are loaded to inode buffer (flash to memory with cache inhibited) in memory and then (mem)copied to the destination address (memory to memory). (Hope I got this right). This is why the cache/memory is not in sync.
The problem does not exist when the cache is write-through.
Also the Freescale documentation on cache cohenrency specifies that software should make sure that the cache/memory are synchronized before jumping to a new location.
Hence, I think the cache should be flushed in or after do_jffs2_fsload. A call to flush_dcache(); fixes the problem.
Let me know if you think I am right regarding this issue.
cheers, Renaud