From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e32.co.us.ibm.com (e32.co.us.ibm.com [32.97.110.150]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e32.co.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id B9B3CDDF50 for ; Wed, 9 Apr 2008 02:49:23 +1000 (EST) Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e32.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id m38GlLOK010446 for ; Tue, 8 Apr 2008 12:47:21 -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 m38GnKBK194456 for ; Tue, 8 Apr 2008 10:49:20 -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 m38GnJrL030655 for ; Tue, 8 Apr 2008 10:49:19 -0600 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Subject: [PATCH] [v5] Add idle wait support for 44x platforms Message-Id: Date: Tue, 08 Apr 2008 11:49:14 -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, 77 insertions(+), 1 deletion(-) arch/powerpc/platforms/44x/Makefile | 2 arch/powerpc/platforms/44x/idle.c | 76 +++++++++++++++++++++++++++++++++++ Updates: Now setting MSR_WE is now default Tested on hardware platforms bamboo & sequioa and appears things are working fine on actually hardware! 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 idle=spin <-- CPU will spin idle=wait <-- set CPU into wait state when idle (default) 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 +1,76 @@ +/* + * 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|MSR_DE); + isync(); + /* return to initial state */ + mtmsr(msr_save); + isync(); +} + +static struct sleep_mode modes[] = { + { .name = "wait", .entry = &ppc44x_idle }, + { .name = "spin", .entry = NULL }, +}; + +int __init ppc44x_idle_init(void) +{ + void *func = modes[current_mode].entry; + 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);