On Thu, May 24, 2018 at 08:14:40PM -0700, Andrey Smirnov wrote: > On Wed, May 23, 2018 at 1:43 AM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > > On Tue, May 22, 2018 at 10:10:12PM -0700, Andrey Smirnov wrote: > >> The call to create_flat_mapping() in mmu.c will change both memory > >> type and shareability of all RAM in use by barebox while MMU is on > >> when done in conjunction with CONFIG_MMU_EARLY. > > > > I notice that with MMU_EARLY enabled we call create_flat_mapping() > > twice, once in the early MMU code and once when setting up the MMU for > > real. In between we remap the the SDRAM cached which then is reverted > > during the second call to create_flat_mapping(). > > > > This seems unnecessary. Does the following help you? > > Yeah, this, disabling MMU before or having a tlb_invalidate() after > all seem to help. Your patch works fine, but it has a slight weirdness > in my case because early MMU code would mark OCRAM as cached and > regular MMU code wouldn't undo it without the call to > create_flat_mapping(), so I'd end up with slightly different memory > configuration depending on if EARLY_MMU is enabled or not. Other than > that it should work fine. > > The main reason I chose to go "disable MMU" route is because that > follows what ARMv8 MMU code does, but I am perfectly happy with either > solution. Disabling the MMU probably has a performance impact (I would have to remeasure, maybe this is not true at all), that's why I would prefer keeping it enabled. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
