powerpc/pseries/cpuidle: Move processor_idle.c to drivers/cpuidle.

Move the file from arch specific pseries/processor_idle.c
to drivers/cpuidle/cpuidle-pseries.c
Make the relevant Makefile and Kconfig changes.
Also, introduce Kconfig.powerpc in drivers/cpuidle
for all powerpc cpuidle drivers.

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

4 files changed, 381 insertions, 0 deletions

diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index b3fb81d7cf04..f04e25f6c98d 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -35,6 +35,11 @@ depends on ARM
 source "drivers/cpuidle/Kconfig.arm"
 endmenu
 
+menu "POWERPC CPU Idle Drivers"
+depends on PPC
+source "drivers/cpuidle/Kconfig.powerpc"
+endmenu
+
 endif
 
 config ARCH_NEEDS_CPU_IDLE_COUPLED
diff --git a/drivers/cpuidle/Kconfig.powerpc b/drivers/cpuidle/Kconfig.powerpc
new file mode 100644
index 000000000000..8147de522a96
--- /dev/null
+++ b/drivers/cpuidle/Kconfig.powerpc
@@ -0,0 +1,11 @@
+#
+# POWERPC CPU Idle Drivers
+#
+config PSERIES_CPUIDLE
+        bool "Cpuidle driver for pSeries platforms"
+        depends on CPU_IDLE
+        depends on PPC_PSERIES
+        default y
+        help
+          Select this option to enable processor idle state management
+          through cpuidle subsystem.
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index 527be28e5c1e..a6331ad32738 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -13,3 +13,7 @@ obj-$(CONFIG_ARM_KIRKWOOD_CPUIDLE)	+= cpuidle-kirkwood.o
 obj-$(CONFIG_ARM_ZYNQ_CPUIDLE)          += cpuidle-zynq.o
 obj-$(CONFIG_ARM_U8500_CPUIDLE)         += cpuidle-ux500.o
 obj-$(CONFIG_ARM_AT91_CPUIDLE)          += cpuidle-at91.o
+
+###############################################################################
+# POWERPC drivers
+obj-$(CONFIG_PSERIES_CPUIDLE)           += cpuidle-pseries.o
diff --git a/drivers/cpuidle/cpuidle-pseries.c b/drivers/cpuidle/cpuidle-pseries.c
new file mode 100644
index 000000000000..21154782402a
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-pseries.c
@@ -0,0 +1,361 @@
+/*
+ *  cpuidle-pseries - idle state cpuidle driver.
+ *  Adapted from drivers/idle/intel_idle.c and
+ *  drivers/acpi/processor_idle.c
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/cpuidle.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
+
+#include <asm/paca.h>
+#include <asm/reg.h>
+#include <asm/machdep.h>
+#include <asm/firmware.h>
+#include <asm/plpar_wrappers.h>
+
+struct cpuidle_driver pseries_idle_driver = {
+        .name             = "pseries_idle",
+        .owner            = THIS_MODULE,
+};
+
+#define MAX_IDLE_STATE_COUNT    2
+
+static int max_idle_state = MAX_IDLE_STATE_COUNT - 1;
+static struct cpuidle_device __percpu *pseries_cpuidle_devices;
+static struct cpuidle_state *cpuidle_state_table;
+
+static inline void idle_loop_prolog(unsigned long *in_purr)
+{
+        *in_purr = mfspr(SPRN_PURR);
+        /*
+         * Indicate to the HV that we are idle. Now would be
+         * a good time to find other work to dispatch.
+         */
+        get_lppaca()->idle = 1;
+}
+
+static inline void idle_loop_epilog(unsigned long in_purr)
+{
+        u64 wait_cycles;
+
+        wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles);
+        wait_cycles += mfspr(SPRN_PURR) - in_purr;
+        get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
+        get_lppaca()->idle = 0;
+}
+
+static int snooze_loop(struct cpuidle_device *dev,
+                        struct cpuidle_driver *drv,
+                        int index)
+{
+        unsigned long in_purr;
+        int cpu = dev->cpu;
+
+        idle_loop_prolog(&in_purr);
+        local_irq_enable();
+        set_thread_flag(TIF_POLLING_NRFLAG);
+
+        while ((!need_resched()) && cpu_online(cpu)) {
+                HMT_low();
+                HMT_very_low();
+        }
+
+        HMT_medium();
+        clear_thread_flag(TIF_POLLING_NRFLAG);
+        smp_mb();
+
+        idle_loop_epilog(in_purr);
+
+        return index;
+}
+
+static void check_and_cede_processor(void)
+{
+        /*
+         * Ensure our interrupt state is properly tracked,
+         * also checks if no interrupt has occurred while we
+         * were soft-disabled
+         */
+        if (prep_irq_for_idle()) {
+                cede_processor();
+#ifdef CONFIG_TRACE_IRQFLAGS
+                /* Ensure that H_CEDE returns with IRQs on */
+                if (WARN_ON(!(mfmsr() & MSR_EE)))
+                        __hard_irq_enable();
+#endif
+        }
+}
+
+static int dedicated_cede_loop(struct cpuidle_device *dev,
+                                struct cpuidle_driver *drv,
+                                int index)
+{
+        unsigned long in_purr;
+
+        idle_loop_prolog(&in_purr);
+        get_lppaca()->donate_dedicated_cpu = 1;
+
+        HMT_medium();
+        check_and_cede_processor();
+
+        get_lppaca()->donate_dedicated_cpu = 0;
+
+        idle_loop_epilog(in_purr);
+
+        return index;
+}
+
+static int shared_cede_loop(struct cpuidle_device *dev,
+                        struct cpuidle_driver *drv,
+                        int index)
+{
+        unsigned long in_purr;
+
+        idle_loop_prolog(&in_purr);
+
+        /*
+         * 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_and_cede_processor();
+
+        idle_loop_epilog(in_purr);
+
+        return index;
+}
+
+/*
+ * States for dedicated partition case.
+ */
+static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = {
+        { /* Snooze */
+                .name = "snooze",
+                .desc = "snooze",
+                .flags = CPUIDLE_FLAG_TIME_VALID,
+                .exit_latency = 0,
+                .target_residency = 0,
+                .enter = &snooze_loop },
+        { /* CEDE */
+                .name = "CEDE",
+                .desc = "CEDE",
+                .flags = CPUIDLE_FLAG_TIME_VALID,
+                .exit_latency = 10,
+                .target_residency = 100,
+                .enter = &dedicated_cede_loop },
+};
+
+/*
+ * States for shared partition case.
+ */
+static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = {
+        { /* Shared Cede */
+                .name = "Shared Cede",
+                .desc = "Shared Cede",
+                .flags = CPUIDLE_FLAG_TIME_VALID,
+                .exit_latency = 0,
+                .target_residency = 0,
+                .enter = &shared_cede_loop },
+};
+
+void update_smt_snooze_delay(int cpu, int residency)
+{
+        struct cpuidle_driver *drv = cpuidle_get_driver();
+        struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
+
+        if (cpuidle_state_table != dedicated_states)
+                return;
+
+        if (residency < 0) {
+                /* Disable the Nap state on that cpu */
+                if (dev)
+                        dev->states_usage[1].disable = 1;
+        } else
+                if (drv)
+                        drv->states[1].target_residency = residency;
+}
+
+static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,
+                        unsigned long action, void *hcpu)
+{
+        int hotcpu = (unsigned long)hcpu;
+        struct cpuidle_device *dev =
+                        per_cpu_ptr(pseries_cpuidle_devices, hotcpu);
+
+        if (dev && cpuidle_get_driver()) {
+                switch (action) {
+                case CPU_ONLINE:
+                case CPU_ONLINE_FROZEN:
+                        cpuidle_pause_and_lock();
+                        cpuidle_enable_device(dev);
+                        cpuidle_resume_and_unlock();
+                        break;
+
+                case CPU_DEAD:
+                case CPU_DEAD_FROZEN:
+                        cpuidle_pause_and_lock();
+                        cpuidle_disable_device(dev);
+                        cpuidle_resume_and_unlock();
+                        break;
+
+                default:
+                        return NOTIFY_DONE;
+                }
+        }
+        return NOTIFY_OK;
+}
+
+static struct notifier_block setup_hotplug_notifier = {
+        .notifier_call = pseries_cpuidle_add_cpu_notifier,
+};
+
+/*
+ * pseries_cpuidle_driver_init()
+ */
+static int pseries_cpuidle_driver_init(void)
+{
+        int idle_state;
+        struct cpuidle_driver *drv = &pseries_idle_driver;
+
+        drv->state_count = 0;
+
+        for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) {
+
+                if (idle_state > max_idle_state)
+                        break;
+
+                /* is the state not enabled? */
+                if (cpuidle_state_table[idle_state].enter == NULL)
+                        continue;
+
+                drv->states[drv->state_count] = /* structure copy */
+                        cpuidle_state_table[idle_state];
+
+                drv->state_count += 1;
+        }
+
+        return 0;
+}
+
+/* pseries_idle_devices_uninit(void)
+ * unregister cpuidle devices and de-allocate memory
+ */
+static void pseries_idle_devices_uninit(void)
+{
+        int i;
+        struct cpuidle_device *dev;
+
+        for_each_possible_cpu(i) {
+                dev = per_cpu_ptr(pseries_cpuidle_devices, i);
+                cpuidle_unregister_device(dev);
+        }
+
+        free_percpu(pseries_cpuidle_devices);
+        return;
+}
+
+/* pseries_idle_devices_init()
+ * allocate, initialize and register cpuidle device
+ */
+static int pseries_idle_devices_init(void)
+{
+        int i;
+        struct cpuidle_driver *drv = &pseries_idle_driver;
+        struct cpuidle_device *dev;
+
+        pseries_cpuidle_devices = alloc_percpu(struct cpuidle_device);
+        if (pseries_cpuidle_devices == NULL)
+                return -ENOMEM;
+
+        for_each_possible_cpu(i) {
+                dev = per_cpu_ptr(pseries_cpuidle_devices, i);
+                dev->state_count = drv->state_count;
+                dev->cpu = i;
+                if (cpuidle_register_device(dev)) {
+                        printk(KERN_DEBUG \
+                                "cpuidle_register_device %d failed!\n", i);
+                        return -EIO;
+                }
+        }
+
+        return 0;
+}
+
+/*
+ * pseries_idle_probe()
+ * Choose state table for shared versus dedicated partition
+ */
+static int pseries_idle_probe(void)
+{
+
+        if (!firmware_has_feature(FW_FEATURE_SPLPAR))
+                return -ENODEV;
+
+        if (cpuidle_disable != IDLE_NO_OVERRIDE)
+                return -ENODEV;
+
+        if (max_idle_state == 0) {
+                printk(KERN_DEBUG "pseries processor idle disabled.\n");
+                return -EPERM;
+        }
+
+        if (lppaca_shared_proc(get_lppaca()))
+                cpuidle_state_table = shared_states;
+        else
+                cpuidle_state_table = dedicated_states;
+
+        return 0;
+}
+
+static int __init pseries_processor_idle_init(void)
+{
+        int retval;
+
+        retval = pseries_idle_probe();
+        if (retval)
+                return retval;
+
+        pseries_cpuidle_driver_init();
+        retval = cpuidle_register_driver(&pseries_idle_driver);
+        if (retval) {
+                printk(KERN_DEBUG "Registration of pseries driver failed.\n");
+                return retval;
+        }
+
+        retval = pseries_idle_devices_init();
+        if (retval) {
+                pseries_idle_devices_uninit();
+                cpuidle_unregister_driver(&pseries_idle_driver);
+                return retval;
+        }
+
+        register_cpu_notifier(&setup_hotplug_notifier);
+        printk(KERN_DEBUG "pseries_idle_driver registered\n");
+
+        return 0;
+}
+
+static void __exit pseries_processor_idle_exit(void)
+{
+
+        unregister_cpu_notifier(&setup_hotplug_notifier);
+        pseries_idle_devices_uninit();
+        cpuidle_unregister_driver(&pseries_idle_driver);
+
+        return;
+}
+
+module_init(pseries_processor_idle_init);
+module_exit(pseries_processor_idle_exit);
+
+MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("Cpuidle driver for POWER");
+MODULE_LICENSE("GPL");