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 <[EMAIL PROTECTED]>
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 <[EMAIL PROTECTED]>
+ *
+ * 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 <linux/of.h>
+#include <linux/kernel.h>
+#include <asm/machdep.h>
+
+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);
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