From mboxrd@z Thu Jan 1 00:00:00 1970 From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni) Date: Tue, 15 May 2012 17:46:02 +0200 Subject: [PATCH 6/8] arm: mach-armada: add support for Armada XP board with device tree In-Reply-To: <201205151532.21143.arnd@arndb.de> References: <1337072084-21967-1-git-send-email-thomas.petazzoni@free-electrons.com> <20120515165813.66b4434e@skate> <4FB2714F.5080703@codethink.co.uk> <201205151532.21143.arnd@arndb.de> Message-ID: <20120515174602.26d02f70@skate> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Le Tue, 15 May 2012 15:32:20 +0000, Arnd Bergmann a ?crit : > > > Agreed. When looking at the code, I wasn't sure why PCI mappings > > > were needed so early. Surely, the minimal mappings to get an UART > > > are quite useful to have very early, but why PCI? > > > > I think it was because that PCI was initialised early and requires a > > large mapping space. It is very likely to be legacy kernel stuff > > that people have kept copying through. > > No, as Rob pointed out, we might not need them early, but we > definitely want a fixed address for the PIO window, which ioremap > does not provide. A fixed address for the PIO window of the PCI registers? Or a fixed address for the PIO window used to access UART registers? I would understand why a fixed address is needed for the latter, but not really for the former. Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com