[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>

2 files changed, 34 insertions, 69 deletions

diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 4180c3998b39..8994af327b47 100644
--- 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 fdcd89e99f1b..c68fabdc7874 100644
--- 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;
 }