On 10/18/2012 08:54 AM, Russell King - ARM Linux wrote: > On Thu, Oct 18, 2012 at 08:47:56AM -0500, Rob Herring wrote: >> Here is what I mentioned previously. This removes the static mapping from >> the platforms. This is untested and probably breaks on different DEBUG_LL >> options. For now, platforms call debug_ll_io_init, but once all platforms >> are converted, this can be called from devicemaps_init. > > There's a problem with this approach. What if the platform specifically > sets the debug addresses to be within one of it's existing mappings (which > is definitely what you'd want to do with 8250-based UARTs attached to a > PCI bus.) > > This isn't going to work in that case unless we split the debug mapping > from the PCI IO space mapping. It is opt-in, so we may never get to the last step. We're still better off than now. Is there a platform that is doing this? If so, I didn't move any DEBUG_LL users to the fixed i/o space so they would still be using their old i/o space address. Having 2 mappings would work, right? You use the debug mapping initially and when PCI bus and the real console driver are up, you switch to the fixed i/o space. This isn't just a PCI issue. You could also have a mapping that covers a block of SOC peripherals including the uart and you don't want a separate mapping. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
