From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755912AbeCHPAc (ORCPT ); Thu, 8 Mar 2018 10:00:32 -0500 Received: from mirror2.csie.ntu.edu.tw ([140.112.30.76]:47236 "EHLO wens.csie.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752072AbeCHPA2 (ORCPT ); Thu, 8 Mar 2018 10:00:28 -0500 From: Chen-Yu Tsai To: Maxime Ripard , Rob Herring , Mark Rutland Cc: Chen-Yu Tsai , Mylene Josserand , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Subject: [PATCH 2/4] ARM: sunxi: mc-smp: Use DT enable-method for sun9i A80 SMP Date: Thu, 8 Mar 2018 23:00:10 +0800 Message-Id: <20180308150012.19045-3-wens@csie.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180308150012.19045-1-wens@csie.org> References: <20180308150012.19045-1-wens@csie.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Instead of having an early init function check the machine compatible and installing multi-cluster SMP support for the A80 if it matches, use a new cpu enable-method string. This makes the platform support future proof in case anyone manages to add PSCI support. The original init code for the SMP support is changed into the .prepare_cpus callback in the smp_operations structure. Instead of panicing when resources are missing like on some platforms, our code merely guards against engaging SMP or CPU hotplug and returns an error. Signed-off-by: Chen-Yu Tsai --- Documentation/devicetree/bindings/arm/cpus.txt | 1 + arch/arm/mach-sunxi/mc_smp.c | 21 ++++++++++++++++++++- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt index f4a777039f03..76655d0d67c2 100644 --- a/Documentation/devicetree/bindings/arm/cpus.txt +++ b/Documentation/devicetree/bindings/arm/cpus.txt @@ -198,6 +198,7 @@ described below. "actions,s500-smp" "allwinner,sun6i-a31" "allwinner,sun8i-a23" + "allwinner,sun9i-a80-smp" "amlogic,meson8-smp" "amlogic,meson8b-smp" "arm,realview-smp" diff --git a/arch/arm/mach-sunxi/mc_smp.c b/arch/arm/mach-sunxi/mc_smp.c index 9db6c4ed5861..86e90b038555 100644 --- a/arch/arm/mach-sunxi/mc_smp.c +++ b/arch/arm/mach-sunxi/mc_smp.c @@ -690,7 +690,26 @@ static int __init sunxi_mc_smp_init(void) struct resource res; int ret; - if (!of_machine_is_compatible("allwinner,sun9i-a80")) + /* + * Don't bother checking the "cpus" node, as an enable-method + * property in that node is undocumented. + */ + node = of_cpu_device_node_get(0); + if (!node) + return -ENODEV; + + /* + * We can't actually use the enable-method magic in the kernel. + * Our loopback / trampoline code uses the CPU suspend framework, + * which requires the identity mapping be available. It would not + * yet be available if we used the .init_cpus or .prepare_cpus + * callbacks in smp_operations, which we would use if we were to + * use CPU_METHOD_OF_DECLARE + */ + ret = of_property_match_string(node, "enable-method", + "allwinner,sun9i-a80-smp"); + of_node_put(node); + if (ret) return -ENODEV; if (!sunxi_mc_smp_cpu_table_init()) -- 2.16.2