From mboxrd@z Thu Jan 1 00:00:00 1970 From: geert+renesas@glider.be (Geert Uytterhoeven) Date: Tue, 4 Jul 2017 19:02:11 +0200 Subject: [PATCH 0/2] ARM: renesas: Enable SMP on R-Car E2 Message-ID: <1499187733-1430-1-git-send-email-geert+renesas@glider.be> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Magnus, Mar[ck], Sergei, Simon, This patch series enables SMP on R-Car E2 (r8a7794). - The first patch initializes CNTVOFF for secondary CPU cores, like is already done for the boot CPU core. Without this, the ARM arch timer doesn't work on secondary CPU cores. - The second patch adds the required infrastructure (APMU device node and corresponding enable-method) to DT. This must not be applied on a branch that doesn't have the first patch! According to the original comments, the CNTVOFF initialization is needed on Cortex-A7 only, hence affects R-Car E2, which has a dual Cortex-A7 cluster. Apparently it's not needed on other R-Car Gen2 members that have (only) Cortex-A15 clusters. Perhaps it's also needed on R-Car H2, which has a big.LITTLE quad Cortex-A15 + quad Cortex-A7 configuration, when running Linux on the Cortex-A7 cores? How can I test that? Thanks for your comments! Geert Uytterhoeven (1): ARM: shmobile: Add CA7 arch_timer initialization for secondary CPUs Sergei Shtylyov (1): ARM: dts: r8a7794: Add SMP support arch/arm/boot/dts/r8a7794.dtsi | 7 +++++++ arch/arm/mach-shmobile/Makefile | 1 + arch/arm/mach-shmobile/common.h | 1 + arch/arm/mach-shmobile/headsmp-apmu.S | 38 +++++++++++++++++++++++++++++++++++ arch/arm/mach-shmobile/platsmp-apmu.c | 2 +- 5 files changed, 48 insertions(+), 1 deletion(-) create mode 100644 arch/arm/mach-shmobile/headsmp-apmu.S -- 2.7.4 Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds