From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e34.co.us.ibm.com (e34.co.us.ibm.com [32.97.110.152]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e34.co.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id DABEDDE124 for ; Sat, 12 Apr 2008 05:04:08 +1000 (EST) Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e34.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id m3BJ23MX031911 for ; Fri, 11 Apr 2008 15:02:03 -0400 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m3BJ44QW202908 for ; Fri, 11 Apr 2008 13:04:04 -0600 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m3BJ43rU025590 for ; Fri, 11 Apr 2008 13:04:04 -0600 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Subject: [PATCH] [v6] Add idle wait support for 44x platforms Message-Id: <49d7a8564d97c67b66fa.1207940613@thinkpadL> Date: Fri, 11 Apr 2008 14:03:33 -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, 68 insertions(+), 1 deletion(-) arch/powerpc/platforms/44x/Makefile | 2 - arch/powerpc/platforms/44x/idle.c | 67 +++++++++++++++++++++++++++++++++++ Updates: Shrink code even more from comments made on the list 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. Command line options: idle=spin <-- CPU will spin By default will go into wait mode. 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 +1,67 @@ +/* + * 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 mode_spin; + +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|MSR_DE); + isync(); + /* return to initial state */ + mtmsr(msr_save); + isync(); +} + +int __init ppc44x_idle_init(void) +{ + if (!mode_spin) { + /* If we are not setting spin mode + then we set to wait mode */ + ppc_md.power_save = &ppc44x_idle; + } + + return 0; +} + +arch_initcall(ppc44x_idle_init); + +static int __init idle_param(char *p) +{ + + if (!strcmp("spin", p)) { + mode_spin = 1; + ppc_md.power_save = NULL; + } + + return 0; +} + +early_param("idle", idle_param);