From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e31.co.us.ibm.com (e31.co.us.ibm.com [32.97.110.149]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e31.co.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 6A74FDE072 for ; Sat, 5 Apr 2008 02:50:19 +1100 (EST) Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e31.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id m34FoHGa017329 for ; Fri, 4 Apr 2008 11:50:17 -0400 Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m34FoGtQ099696 for ; Fri, 4 Apr 2008 09:50:16 -0600 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m34FoGXN004269 for ; Fri, 4 Apr 2008 09:50:16 -0600 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Subject: [PATCH] [v3] Add idle wait support for 44x platforms Message-Id: Date: Fri, 04 Apr 2008 10:50:11 -0500 From: Jerone Young To: linuxppc-dev@ozlabs.org Cc: kvm-ppc-devel@lists.sourceforge.net List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 2 files changed, 87 insertions(+), 1 deletion(-) arch/powerpc/platforms/44x/Makefile | 2 arch/powerpc/platforms/44x/idle.c | 86 +++++++++++++++++++++++++++++++++++ This patch adds the ability for the CPU to go into wait state while in cpu_idle loop. This helps virtulization solutions know when the guest Linux kernel is in an idle state. There are two ways to do it. 1) Command line idle=spin <-- CPU will spin (this is the default) idle=wait <-- set CPU into wait state when idle 2) The device tree will be checked for the "/hypervisor" node If this node is seen it will use "wait" for idle, so that the hypervisor can know when guest Linux kernel it is in an idle state. This patch, unlike the last, isolates the code to 44x platforms. Signed-off-by: Jerone Young diff --git a/arch/powerpc/platforms/44x/Makefile b/arch/powerpc/platforms/44x/Makefile --- a/arch/powerpc/platforms/44x/Makefile +++ b/arch/powerpc/platforms/44x/Makefile @@ -1,4 +1,4 @@ obj-$(CONFIG_44x) := misc_44x.o -obj-$(CONFIG_44x) := misc_44x.o +obj-$(CONFIG_44x) := misc_44x.o idle.o obj-$(CONFIG_EBONY) += ebony.o obj-$(CONFIG_TAISHAN) += taishan.o obj-$(CONFIG_BAMBOO) += bamboo.o diff --git a/arch/powerpc/platforms/44x/idle.c b/arch/powerpc/platforms/44x/idle.c new file mode 100644 --- /dev/null +++ b/arch/powerpc/platforms/44x/idle.c @@ -0,0 +1,86 @@ +/* + * Copyright 2008 IBM Corp. + * + * Based on arch/powerpc/platforms/pasemi/idle.c: + * Copyright (C) 2006-2007 PA Semi, Inc + * + * Added by: Jerone Young + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +#include +#include +#include + +static int current_mode; + +struct sleep_mode { + char *name; + void (*entry)(void); +}; + +static void ppc44x_idle(void) +{ + unsigned long msr_save; + + msr_save = mfmsr(); + /* set wait state MSR */ + mtmsr(msr_save|MSR_WE|MSR_EE|MSR_CE); + isync(); + /* return to initial state */ + mtmsr(msr_save); + isync(); +} + +static struct sleep_mode modes[] = { + { .name = "spin", .entry = NULL }, + { .name = "wait", .entry = &ppc44x_idle }, +}; + +int __init ppc44x_idle_init(void) +{ + void *func = modes[current_mode].entry; + struct device_node *node; + + node = of_find_node_by_path("/hypervisor"); + if (node) { + /* if we find /hypervisor node is in device tree, + set idle mode to wait */ + func = &ppc44x_idle; /* wait */ + of_node_put(node); + } + + ppc_md.power_save = func; + return 0; +} + +arch_initcall(ppc44x_idle_init); + +static int __init idle_param(char *p) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(modes); i++) { + if (!strcmp(modes[i].name, p)) { + current_mode = i; + break; + } + } + + return 0; +} + +early_param("idle", idle_param);