powerpc/powernv/cpuidle: Back-end cpuidle driver for powernv platform.

Following patch ports the cpuidle framework for powernv
platform and also implements a cpuidle back-end powernv
idle driver calling on to power7_nap and snooze idle states.

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

diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index a932feb..21166f6 100644 (file)
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -26,6 +26,7 @@
 #include <linux/of_fdt.h>
 #include <linux/interrupt.h>
 #include <linux/bug.h>
+#include <linux/cpuidle.h>
 
 #include <asm/machdep.h>
 #include <asm/firmware.h>
@@ -216,6 +217,16 @@ static int __init pnv_probe(void)
        return 1;
 }
 
+void powernv_idle(void)
+{
+       /* Hook to cpuidle framework if available, else
+        * call on default platform idle code
+        */
+       if (cpuidle_idle_call()) {
+               power7_idle();
+       }
+}
+
 define_machine(powernv) {
        .name                   = "PowerNV",
        .probe                  = pnv_probe,
@@ -225,7 +236,7 @@ define_machine(powernv) {
        .show_cpuinfo           = pnv_show_cpuinfo,
        .progress               = pnv_progress,
        .machine_shutdown       = pnv_shutdown,
-       .power_save             = power7_idle,
+       .power_save             = powernv_idle,
        .calibrate_decr         = generic_calibrate_decr,
 #ifdef CONFIG_KEXEC
        .kexec_cpu_down         = pnv_kexec_cpu_down,

diff --git a/drivers/cpuidle/Kconfig.powerpc b/drivers/cpuidle/Kconfig.powerpc
index 8147de5..66c3a09 100644 (file)
--- a/drivers/cpuidle/Kconfig.powerpc
+++ b/drivers/cpuidle/Kconfig.powerpc
@@ -9,3 +9,12 @@ config PSERIES_CPUIDLE
        help
          Select this option to enable processor idle state management
          through cpuidle subsystem.
+
+config POWERNV_CPUIDLE
+       bool "Cpuidle driver for powernv platforms"
+       depends on CPU_IDLE
+       depends on PPC_POWERNV
+       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 a6331ad..f71ae1b 100644 (file)
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_ARM_AT91_CPUIDLE)          += cpuidle-at91.o
 ###############################################################################
 # POWERPC drivers
 obj-$(CONFIG_PSERIES_CPUIDLE)          += cpuidle-pseries.o
+obj-$(CONFIG_POWERNV_CPUIDLE)          += cpuidle-powernv.o

diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
new file mode 100644 (file)
index 0000000..78fd174
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -0,0 +1,169 @@
+/*
+ *  cpuidle-powernv - idle state cpuidle driver.
+ *  Adapted from drivers/cpuidle/cpuidle-pseries
+ *
+ */
+
+#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/machdep.h>
+#include <asm/firmware.h>
+
+struct cpuidle_driver powernv_idle_driver = {
+       .name             = "powernv_idle",
+       .owner            = THIS_MODULE,
+};
+
+static int max_idle_state;
+static struct cpuidle_state *cpuidle_state_table;
+
+static int snooze_loop(struct cpuidle_device *dev,
+                       struct cpuidle_driver *drv,
+                       int index)
+{
+       local_irq_enable();
+       set_thread_flag(TIF_POLLING_NRFLAG);
+
+       while (!need_resched()) {
+               HMT_low();
+               HMT_very_low();
+       }
+
+       HMT_medium();
+       clear_thread_flag(TIF_POLLING_NRFLAG);
+       smp_mb();
+       return index;
+}
+
+static int nap_loop(struct cpuidle_device *dev,
+                       struct cpuidle_driver *drv,
+                       int index)
+{
+       power7_idle();
+       return index;
+}
+
+/*
+ * States for dedicated partition case.
+ */
+static struct cpuidle_state powernv_states[] = {
+       { /* Snooze */
+               .name = "snooze",
+               .desc = "snooze",
+               .flags = CPUIDLE_FLAG_TIME_VALID,
+               .exit_latency = 0,
+               .target_residency = 0,
+               .enter = &snooze_loop },
+       { /* NAP */
+               .name = "NAP",
+               .desc = "NAP",
+               .flags = CPUIDLE_FLAG_TIME_VALID,
+               .exit_latency = 10,
+               .target_residency = 100,
+               .enter = &nap_loop },
+};
+
+static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
+                       unsigned long action, void *hcpu)
+{
+       int hotcpu = (unsigned long)hcpu;
+       struct cpuidle_device *dev =
+                               per_cpu(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 = powernv_cpuidle_add_cpu_notifier,
+};
+
+/*
+ * powernv_cpuidle_driver_init()
+ */
+static int powernv_cpuidle_driver_init(void)
+{
+       int idle_state;
+       struct cpuidle_driver *drv = &powernv_idle_driver;
+
+       drv->state_count = 0;
+
+       for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
+               /* 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;
+}
+
+/*
+ * powernv_idle_probe()
+ * Choose state table for shared versus dedicated partition
+ */
+static int powernv_idle_probe(void)
+{
+
+       if (cpuidle_disable != IDLE_NO_OVERRIDE)
+               return -ENODEV;
+
+       if (firmware_has_feature(FW_FEATURE_OPALv3)) {
+               cpuidle_state_table = powernv_states;
+               max_idle_state = ARRAY_SIZE(powernv_states);
+       } else
+               return -ENODEV;
+
+       return 0;
+}
+
+static int __init powernv_processor_idle_init(void)
+{
+       int retval;
+
+       retval = powernv_idle_probe();
+       if (retval)
+               return retval;
+
+       powernv_cpuidle_driver_init();
+       retval = cpuidle_register(&powernv_idle_driver, NULL);
+       if (retval) {
+               printk(KERN_DEBUG "Registration of powernv driver failed.\n");
+               return retval;
+       }
+
+       register_cpu_notifier(&setup_hotplug_notifier);
+       printk(KERN_DEBUG "powernv_idle_driver registered\n");
+       return 0;
+}
+
+device_initcall(powernv_processor_idle_init);