ioremap_cached in drivers/mtd/maps ?
Hi there,
it looks like only lubbock-flash.c is using ioremap_cached().
Can I use ioremap_cached() with normal NOR flashes? Is it only for DMA transfer from/to flash? Does it improve something when using JFFS2? What do I have to consider? .inval_cache function?
Thanks a million!
Signature · 2 lines
Steven Scholz imc Measurement & Control
Quoted 6 lines · Steven Scholz
Hi there,
it looks like only
lubbock-flash.cis usingioremap_cached().Can I use
ioremap_cached()with normal NOR flashes? Is it only for DMA transfer from/to flash?
you could use it for such, but it also allows an cached area for flash read, which makes it faster to execute code from.
Quoted 2 lines
Does it improve something when using JFFS2? What do I have to consider? .inval_cache function?
It allows the mapping driver to have a seperate read-only cached area, the .inval_cache function is needed to flush this area when writes happen to the un-cached area.
Signature · 3 lines
Ben ([email protected], http://www.fluff.org/) 'a smiley only costs 4 bytes'
Quoted 3 lines · Steven Scholz
Hi there,
it looks like only
lubbock-flash.cis usingioremap_cached().
sa1100-flash could be using it as well.
Quoted 1 line
Can I use
ioremap_cached()with normal NOR flashes?
Yes.
Quoted 5 lines
Is it only for DMA transfer from/to flash?
From flash only.
Does it improve something when using JFFS2?
Much improved read throughput.
Quoted 1 line
What do I have to consider? .inval_cache function?
Yep.
Nicolas