From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Tue, 06 Oct 2015 10:37:16 +0200 Subject: [PATCH 0/2] ARM: EXYNOS: Allow to use architected timer In-Reply-To: References: Message-ID: <6613638.q5qyQZxXy7@wuerfel> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tuesday 06 October 2015 11:23:58 Pavel Fedin wrote: > Exynos platform officially uses "multi-core timer" AKA MCT. However, it > also has a possibility to access the same timer using CP15 (AKA > architected timer) registers. > > In order to be able to use KVM, we need CP15 timer support. In its turn, > MCT needs to be turned on before any accesses will work. This patchset > allows to specify "CP15 compatibility mode" for the MCT by inserting > armv7-timer node as a child for MCT device. In this case MCT driver will > only enable the timer, leaving the rest for architected timer driver. IIRC the use of the CP15 timer is not reliable on this platform. I don't have a link ready, but this has come up a few times. Kukjin Kim probably knows the details. Regarding KVM usage, would it be possible to emulate the architected timer from qemu instead? Arnd