* Woodruff, Richard <[EMAIL PROTECTED]> [080903 12:58]: > > > From: [EMAIL PROTECTED] [mailto:linux-omap- > > [EMAIL PROTECTED] On Behalf Of Russell King - ARM Linux > > Sent: Wednesday, September 03, 2008 2:34 PM > <snip> > > The question is why do we need it? If the correct physical address > > is passed, then things should work out just fine anyway, especially > > if drivers start to use ioremap rather than relying on all these fixed > > translations. > > Fixed translations do have some benefits. You can ensure that you are using > section or super section descriptors to cover large areas. This does result > in better TLB usage. Along with freeing up TLB entries you also generally > avoid TLB misses on IO calls which touch a variety of internal spaces as part > of the IRQ sequence. > > With in a family of chips like 2420/22/23 or 3410/20/30/40 the internal space > is mapped the same.
I guess there's no advantage of using ioremap if the area is already mapped. For drivers that are shared across multiple archs or buses it makes sense. > Frankly I've never been convinced that a multi OMAP1/2/3 image makes much > sense apart forcing better code structure and being kind of cool. Each chip > has very different performance targets and is really better built with an > optimized tool chain (ARMv5, ARMv6, ARMv7). Doing multi-boots with in the > same architecture family seems really good but across seems less so. It definitely makes sense from distro and maintenance point of view. If we did not work towards multi-omap we would already have the same code duplicated many times over. Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
