On Wednesday 03 September 2008, Woodruff, Richard wrote: > > > ... [ big/inexpensive fixed mappings can be virtuous ... ] > > > > ... which is exactly why some linux/arch/... code makes sure ioremap() > > can return fixed mappings instead of always requiring dynamic ones. > > That does sound like a nice consistent way to do it. Which implementation > of this would you recommend looking at? Do any ARMs you know of do it today? I was just calling attention to the possibility. ISTR seeing that AVR32 does that, and I think some MIPS hardware has the same kind of logic. Not just those, either. The ARM stuff seems to have changed since last I looked! In arch/arm/include/asm/io.h there's an __arch_ioremap() hook; it could be used instead of __arm_ioremap() ... and it seems <mach/io.h> would define __arch_ioremap(). So at a first glance, OMAPs _could_ define that arch function to look at the physical address to see if it's covered by a fixed mapping, then reuse it ... else use __arm_ioremap(). According to Mr. Grep, there are at least 10 ARMs that work like that in mainline. Maybe Russell can recommend one of them as a preferred model. - Dave -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
