1 files changed, 380 insertions, 0 deletions

diff --git a/arch/ppc64/kernel/idle.c b/arch/ppc64/kernel/idle.c
new file mode 100644
index 000000000000..6abc621d3ba0
--- /dev/null
+++ b/arch/ppc64/kernel/idle.c
@@ -0,0 +1,380 @@
+/*
+ * Idle daemon for PowerPC.  Idle daemon will handle any action
+ * that needs to be taken when the system becomes idle.
+ *
+ * Originally Written by Cort Dougan (cort@cs.nmt.edu)
+ *
+ * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com>
+ *
+ * Additional shared processor, SMT, and firmware support
+ *    Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/cpu.h>
+#include <linux/module.h>
+#include <linux/sysctl.h>
+#include <linux/smp.h>
+
+#include <asm/system.h>
+#include <asm/processor.h>
+#include <asm/mmu.h>
+#include <asm/cputable.h>
+#include <asm/time.h>
+#include <asm/iSeries/HvCall.h>
+#include <asm/iSeries/ItLpQueue.h>
+#include <asm/plpar_wrappers.h>
+#include <asm/systemcfg.h>
+
+extern void power4_idle(void);
+
+static int (*idle_loop)(void);
+
+#ifdef CONFIG_PPC_ISERIES
+static unsigned long maxYieldTime = 0;
+static unsigned long minYieldTime = 0xffffffffffffffffUL;
+
+static void yield_shared_processor(void)
+{
+        unsigned long tb;
+        unsigned long yieldTime;
+
+        HvCall_setEnabledInterrupts(HvCall_MaskIPI |
+                                    HvCall_MaskLpEvent |
+                                    HvCall_MaskLpProd |
+                                    HvCall_MaskTimeout);
+
+        tb = get_tb();
+        /* Compute future tb value when yield should expire */
+        HvCall_yieldProcessor(HvCall_YieldTimed, tb+tb_ticks_per_jiffy);
+
+        yieldTime = get_tb() - tb;
+        if (yieldTime > maxYieldTime)
+                maxYieldTime = yieldTime;
+
+        if (yieldTime < minYieldTime)
+                minYieldTime = yieldTime;
+        
+        /*
+         * The decrementer stops during the yield.  Force a fake decrementer
+         * here and let the timer_interrupt code sort out the actual time.
+         */
+        get_paca()->lppaca.int_dword.fields.decr_int = 1;
+        process_iSeries_events();
+}
+
+static int iSeries_idle(void)
+{
+        struct paca_struct *lpaca;
+        long oldval;
+        unsigned long CTRL;
+
+        /* ensure iSeries run light will be out when idle */
+        clear_thread_flag(TIF_RUN_LIGHT);
+        CTRL = mfspr(CTRLF);
+        CTRL &= ~RUNLATCH;
+        mtspr(CTRLT, CTRL);
+
+        lpaca = get_paca();
+
+        while (1) {
+                if (lpaca->lppaca.shared_proc) {
+                        if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
+                                process_iSeries_events();
+                        if (!need_resched())
+                                yield_shared_processor();
+                } else {
+                        oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
+
+                        if (!oldval) {
+                                set_thread_flag(TIF_POLLING_NRFLAG);
+
+                                while (!need_resched()) {
+                                        HMT_medium();
+                                        if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
+                                                process_iSeries_events();
+                                        HMT_low();
+                                }
+
+                                HMT_medium();
+                                clear_thread_flag(TIF_POLLING_NRFLAG);
+                        } else {
+                                set_need_resched();
+                        }
+                }
+
+                schedule();
+        }
+
+        return 0;
+}
+
+#else
+
+static int default_idle(void)
+{
+        long oldval;
+        unsigned int cpu = smp_processor_id();
+
+        while (1) {
+                oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
+
+                if (!oldval) {
+                        set_thread_flag(TIF_POLLING_NRFLAG);
+
+                        while (!need_resched() && !cpu_is_offline(cpu)) {
+                                barrier();
+                                /*
+                                 * Go into low thread priority and possibly
+                                 * low power mode.
+                                 */
+                                HMT_low();
+                                HMT_very_low();
+                        }
+
+                        HMT_medium();
+                        clear_thread_flag(TIF_POLLING_NRFLAG);
+                } else {
+                        set_need_resched();
+                }
+
+                schedule();
+                if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
+                        cpu_die();
+        }
+
+        return 0;
+}
+
+#ifdef CONFIG_PPC_PSERIES
+
+DECLARE_PER_CPU(unsigned long, smt_snooze_delay);
+
+int dedicated_idle(void)
+{
+        long oldval;
+        struct paca_struct *lpaca = get_paca(), *ppaca;
+        unsigned long start_snooze;
+        unsigned long *smt_snooze_delay = &__get_cpu_var(smt_snooze_delay);
+        unsigned int cpu = smp_processor_id();
+
+        ppaca = &paca[cpu ^ 1];
+
+        while (1) {
+                /*
+                 * Indicate to the HV that we are idle. Now would be
+                 * a good time to find other work to dispatch.
+                 */
+                lpaca->lppaca.idle = 1;
+
+                oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
+                if (!oldval) {
+                        set_thread_flag(TIF_POLLING_NRFLAG);
+                        start_snooze = __get_tb() +
+                                *smt_snooze_delay * tb_ticks_per_usec;
+                        while (!need_resched() && !cpu_is_offline(cpu)) {
+                                /*
+                                 * Go into low thread priority and possibly
+                                 * low power mode.
+                                 */
+                                HMT_low();
+                                HMT_very_low();
+
+                                if (*smt_snooze_delay == 0 ||
+                                    __get_tb() < start_snooze)
+                                        continue;
+
+                                HMT_medium();
+
+                                if (!(ppaca->lppaca.idle)) {
+                                        local_irq_disable();
+
+                                        /*
+                                         * We are about to sleep the thread
+                                         * and so wont be polling any
+                                         * more.
+                                         */
+                                        clear_thread_flag(TIF_POLLING_NRFLAG);
+
+                                        /*
+                                         * SMT dynamic mode. Cede will result
+                                         * in this thread going dormant, if the
+                                         * partner thread is still doing work.
+                                         * Thread wakes up if partner goes idle,
+                                         * an interrupt is presented, or a prod
+                                         * occurs.  Returning from the cede
+                                         * enables external interrupts.
+                                         */
+                                        if (!need_resched())
+                                                cede_processor();
+                                        else
+                                                local_irq_enable();
+                                } else {
+                                        /*
+                                         * Give the HV an opportunity at the
+                                         * processor, since we are not doing
+                                         * any work.
+                                         */
+                                        poll_pending();
+                                }
+                        }
+
+                        clear_thread_flag(TIF_POLLING_NRFLAG);
+                } else {
+                        set_need_resched();
+                }
+
+                HMT_medium();
+                lpaca->lppaca.idle = 0;
+                schedule();
+                if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
+                        cpu_die();
+        }
+        return 0;
+}
+
+static int shared_idle(void)
+{
+        struct paca_struct *lpaca = get_paca();
+        unsigned int cpu = smp_processor_id();
+
+        while (1) {
+                /*
+                 * Indicate to the HV that we are idle. Now would be
+                 * a good time to find other work to dispatch.
+                 */
+                lpaca->lppaca.idle = 1;
+
+                while (!need_resched() && !cpu_is_offline(cpu)) {
+                        local_irq_disable();
+
+                        /*
+                         * Yield the processor to the hypervisor.  We return if
+                         * an external interrupt occurs (which are driven prior
+                         * to returning here) or if a prod occurs from another 
+                         * processor. When returning here, external interrupts
+                         * are enabled.
+                         *
+                         * Check need_resched() again with interrupts disabled
+                         * to avoid a race.
+                         */
+                        if (!need_resched())
+                                cede_processor();
+                        else
+                                local_irq_enable();
+                }
+
+                HMT_medium();
+                lpaca->lppaca.idle = 0;
+                schedule();
+                if (cpu_is_offline(smp_processor_id()) &&
+                    system_state == SYSTEM_RUNNING)
+                        cpu_die();
+        }
+
+        return 0;
+}
+
+#endif /* CONFIG_PPC_PSERIES */
+
+static int native_idle(void)
+{
+        while(1) {
+                /* check CPU type here */
+                if (!need_resched())
+                        power4_idle();
+                if (need_resched())
+                        schedule();
+
+                if (cpu_is_offline(_smp_processor_id()) &&
+                    system_state == SYSTEM_RUNNING)
+                        cpu_die();
+        }
+        return 0;
+}
+
+#endif /* CONFIG_PPC_ISERIES */
+
+void cpu_idle(void)
+{
+        idle_loop();
+}
+
+int powersave_nap;
+
+#ifdef CONFIG_SYSCTL
+/*
+ * Register the sysctl to set/clear powersave_nap.
+ */
+static ctl_table powersave_nap_ctl_table[]={
+        {
+                .ctl_name       = KERN_PPC_POWERSAVE_NAP,
+                .procname       = "powersave-nap",
+                .data           = &powersave_nap,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec,
+        },
+        { 0, },
+};
+static ctl_table powersave_nap_sysctl_root[] = {
+        { 1, "kernel", NULL, 0, 0755, powersave_nap_ctl_table, },
+        { 0,},
+};
+
+static int __init
+register_powersave_nap_sysctl(void)
+{
+        register_sysctl_table(powersave_nap_sysctl_root, 0);
+
+        return 0;
+}
+__initcall(register_powersave_nap_sysctl);
+#endif
+
+int idle_setup(void)
+{
+        /*
+         * Move that junk to each platform specific file, eventually define
+         * a pSeries_idle for shared processor stuff
+         */
+#ifdef CONFIG_PPC_ISERIES
+        idle_loop = iSeries_idle;
+        return 1;
+#else
+        idle_loop = default_idle;
+#endif
+#ifdef CONFIG_PPC_PSERIES
+        if (systemcfg->platform & PLATFORM_PSERIES) {
+                if (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR) {
+                        if (get_paca()->lppaca.shared_proc) {
+                                printk(KERN_INFO "Using shared processor idle loop\n");
+                                idle_loop = shared_idle;
+                        } else {
+                                printk(KERN_INFO "Using dedicated idle loop\n");
+                                idle_loop = dedicated_idle;
+                        }
+                } else {
+                        printk(KERN_INFO "Using default idle loop\n");
+                        idle_loop = default_idle;
+                }
+        }
+#endif /* CONFIG_PPC_PSERIES */
+#ifndef CONFIG_PPC_ISERIES
+        if (systemcfg->platform == PLATFORM_POWERMAC ||
+            systemcfg->platform == PLATFORM_MAPLE) {
+                printk(KERN_INFO "Using native/NAP idle loop\n");
+                idle_loop = native_idle;
+        }
+#endif /* CONFIG_PPC_ISERIES */
+
+        return 1;
+}