[POWERPC] cell: use ppc_md->power_save instead of cbe_idle_loop

This moves the cell idle function to use the default cpu_idle
with a special power_save callback, like all other platforms
except iSeries already do.

It also makes it possible to disable this power_save function
with a new powerpc-specific boot option "powersave=off".

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 4180c39..8994af3 100644 (file)
--- a/arch/powerpc/kernel/idle.c
+++ b/arch/powerpc/kernel/idle.c
@@ -39,6 +39,13 @@
 #define cpu_should_die()       0
 #endif
 
+static int __init powersave_off(char *arg)
+{
+       ppc_md.power_save = NULL;
+       return 0;
+}
+__setup("powersave=off", powersave_off);
+
 /*
  * The body of the idle task.
  */

diff --git a/arch/powerpc/platforms/cell/pervasive.c b/arch/powerpc/platforms/cell/pervasive.c
index fdcd89e..c68fabd 100644 (file)
--- a/arch/powerpc/platforms/cell/pervasive.c
+++ b/arch/powerpc/platforms/cell/pervasive.c
@@ -38,32 +38,16 @@
 #include "pervasive.h"
 #include "cbe_regs.h"
 
-static DEFINE_SPINLOCK(cbe_pervasive_lock);
-
-static void __init cbe_enable_pause_zero(void)
+static void cbe_power_save(void)
 {
-       unsigned long thread_switch_control;
-       unsigned long temp_register;
-       struct cbe_pmd_regs __iomem *pregs;
-
-       spin_lock_irq(&cbe_pervasive_lock);
-       pregs = cbe_get_cpu_pmd_regs(smp_processor_id());
-       if (pregs == NULL)
-               goto out;
-
-       pr_debug("Power Management: CPU %d\n", smp_processor_id());
-
-        /* Enable Pause(0) control bit */
-       temp_register = in_be64(&pregs->pmcr);
-
-       out_be64(&pregs->pmcr,
-                temp_register | CBE_PMD_PAUSE_ZERO_CONTROL);
+       unsigned long ctrl, thread_switch_control;
+       ctrl = mfspr(SPRN_CTRLF);
 
        /* Enable DEC and EE interrupt request */
        thread_switch_control  = mfspr(SPRN_TSC_CELL);
        thread_switch_control |= TSC_CELL_EE_ENABLE | TSC_CELL_EE_BOOST;
 
-       switch ((mfspr(SPRN_CTRLF) & CTRL_CT)) {
+       switch (ctrl & CTRL_CT) {
        case CTRL_CT0:
                thread_switch_control |= TSC_CELL_DEC_ENABLE_0;
                break;
@@ -75,58 +59,21 @@ static void __init cbe_enable_pause_zero(void)
                        __FUNCTION__);
                break;
        }
-
        mtspr(SPRN_TSC_CELL, thread_switch_control);
 
-out:
-       spin_unlock_irq(&cbe_pervasive_lock);
-}
-
-static void cbe_idle(void)
-{
-       unsigned long ctrl;
-
-       /* Why do we do that on every idle ? Couldn't that be done once for
-        * all or do we lose the state some way ? Also, the pmcr
-        * register setting, that can't be set once at boot ? We really want
-        * to move that away in order to implement a simple powersave
+       /*
+        * go into low thread priority, medium priority will be
+        * restored for us after wake-up.
         */
-       cbe_enable_pause_zero();
-
-       while (1) {
-               if (!need_resched()) {
-                       local_irq_disable();
-                       while (!need_resched()) {
-                               /* go into low thread priority */
-                               HMT_low();
-
-                               /*
-                                * atomically disable thread execution
-                                * and runlatch.
-                                * External and Decrementer exceptions
-                                * are still handled when the thread
-                                * is disabled but now enter in
-                                * cbe_system_reset_exception()
-                                */
-                               ctrl = mfspr(SPRN_CTRLF);
-                               ctrl &= ~(CTRL_RUNLATCH | CTRL_TE);
-                               mtspr(SPRN_CTRLT, ctrl);
-                       }
-                       /* restore thread prio */
-                       HMT_medium();
-                       local_irq_enable();
-               }
+       HMT_low();
 
-               /*
-                * turn runlatch on again before scheduling the
-                * process we just woke up
-                */
-               ppc64_runlatch_on();
-
-               preempt_enable_no_resched();
-               schedule();
-               preempt_disable();
-       }
+       /*
+        * atomically disable thread execution and runlatch.
+        * External and Decrementer exceptions are still handled when the
+        * thread is disabled but now enter in cbe_system_reset_exception()
+        */
+       ctrl &= ~(CTRL_RUNLATCH | CTRL_TE);
+       mtspr(SPRN_CTRLT, ctrl);
 }
 
 static int cbe_system_reset_exception(struct pt_regs *regs)
@@ -158,9 +105,20 @@ static int cbe_system_reset_exception(struct pt_regs *regs)
 
 void __init cbe_pervasive_init(void)
 {
+       int cpu;
        if (!cpu_has_feature(CPU_FTR_PAUSE_ZERO))
                return;
 
-       ppc_md.idle_loop = cbe_idle;
+       for_each_possible_cpu(cpu) {
+               struct cbe_pmd_regs __iomem *regs = cbe_get_cpu_pmd_regs(cpu);
+               if (!regs)
+                       continue;
+
+                /* Enable Pause(0) control bit */
+               out_be64(&regs->pmcr, in_be64(&regs->pmcr) |
+                                           CBE_PMD_PAUSE_ZERO_CONTROL);
+       }
+
+       ppc_md.power_save = cbe_power_save;
        ppc_md.system_reset_exception = cbe_system_reset_exception;
 }