[POWERPC] PS3: Save power in busy loops on halt

PS3 save power on halt:
  - Replace infinite busy loops by smarter loops calling
    lv1_pause() to save power.
  - Add ps3_halt() and ps3_sys_manager_halt().
  - Add __noreturn annotations.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 30 insertions, 16 deletions

diff --git a/drivers/ps3/ps3-sys-manager.c b/drivers/ps3/ps3-sys-manager.c
index d4f6f960dd18..1260b01a5361 100644
--- a/drivers/ps3/ps3-sys-manager.c
+++ b/drivers/ps3/ps3-sys-manager.c
@@ -24,6 +24,7 @@
 #include <linux/reboot.h>
 
 #include <asm/firmware.h>
+#include <asm/lv1call.h>
 #include <asm/ps3.h>
 
 #include "vuart.h"
@@ -581,6 +582,23 @@ fail_id:
         return -EIO;
 }
 
+static void ps3_sys_manager_fin(struct ps3_system_bus_device *dev)
+{
+        ps3_sys_manager_send_request_shutdown(dev);
+
+        pr_emerg("System Halted, OK to turn off power\n");
+
+        while (ps3_sys_manager_handle_msg(dev)) {
+                /* pause until next DEC interrupt */
+                lv1_pause(0);
+        }
+
+        while (1) {
+                /* pause, ignoring DEC interrupt */
+                lv1_pause(1);
+        }
+}
+
 /**
  * ps3_sys_manager_final_power_off - The final platform machine_power_off routine.
  *
@@ -602,12 +620,8 @@ static void ps3_sys_manager_final_power_off(struct ps3_system_bus_device *dev)
 
         ps3_sys_manager_send_next_op(dev, PS3_SM_NEXT_OP_SYS_SHUTDOWN,
                 PS3_SM_WAKE_DEFAULT);
-        ps3_sys_manager_send_request_shutdown(dev);
-
-        pr_emerg("System Halted, OK to turn off power\n");
 
-        while (1)
-                ps3_sys_manager_handle_msg(dev);
+        ps3_sys_manager_fin(dev);
 }
 
 /**
@@ -639,12 +653,8 @@ static void ps3_sys_manager_final_restart(struct ps3_system_bus_device *dev)
         ps3_sys_manager_send_attr(dev, 0);
         ps3_sys_manager_send_next_op(dev, PS3_SM_NEXT_OP_SYS_REBOOT,
                 PS3_SM_WAKE_DEFAULT);
-        ps3_sys_manager_send_request_shutdown(dev);
-
-        pr_emerg("System Halted, OK to turn off power\n");
 
-        while (1)
-                ps3_sys_manager_handle_msg(dev);
+        ps3_sys_manager_fin(dev);
 }
 
 /**
diff --git a/drivers/ps3/sys-manager-core.c b/drivers/ps3/sys-manager-core.c
index 31648f7d9ae1..474225852b63 100644
--- a/drivers/ps3/sys-manager-core.c
+++ b/drivers/ps3/sys-manager-core.c
@@ -19,6 +19,7 @@
  */
 
 #include <linux/kernel.h>
+#include <asm/lv1call.h>
 #include <asm/ps3.h>
 
 /**
@@ -50,10 +51,7 @@ void ps3_sys_manager_power_off(void)
         if (ps3_sys_manager_ops.power_off)
                 ps3_sys_manager_ops.power_off(ps3_sys_manager_ops.dev);
 
-        printk(KERN_EMERG "System Halted, OK to turn off power\n");
-        local_irq_disable();
-        while (1)
-                (void)0;
+        ps3_sys_manager_halt();
 }
 
 void ps3_sys_manager_restart(void)
@@ -61,8 +59,14 @@ void ps3_sys_manager_restart(void)
         if (ps3_sys_manager_ops.restart)
                 ps3_sys_manager_ops.restart(ps3_sys_manager_ops.dev);
 
-        printk(KERN_EMERG "System Halted, OK to turn off power\n");
+        ps3_sys_manager_halt();
+}
+
+void ps3_sys_manager_halt(void)
+{
+        pr_emerg("System Halted, OK to turn off power\n");
         local_irq_disable();
         while (1)
-                (void)0;
+                lv1_pause(1);
 }
+