Merge branch 'powernv-cpuidle' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

Pull powerpc non-virtualized cpuidle from Ben Herrenschmidt:
 "This is the branch I mentioned in my other pull request which contains
  our improved cpuidle support for the "powernv" platform
  (non-virtualized).

  It adds support for the "fast sleep" feature of the processor which
  provides higher power savings than our usual "nap" mode but at the
  cost of losing the timers while asleep, and thus exploits the new
  timer broadcast framework to work around that limitation.

  It's based on a tip timer tree that you seem to have already merged"

* 'powernv-cpuidle' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  cpuidle/powernv: Parse device tree to setup idle states
  cpuidle/powernv: Add "Fast-Sleep" CPU idle state
  powerpc/powernv: Add OPAL call to resync timebase on wakeup
  powerpc/powernv: Add context management for Fast Sleep
  powerpc: Split timer_interrupt() into timer handling and interrupt handling routines
  powerpc: Implement tick broadcast IPI as a fixed IPI message
  powerpc: Free up the slot of PPC_MSG_CALL_FUNC_SINGLE IPI message

1 files changed, 92 insertions, 10 deletions

diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index f48607cd254..719f6fb5b1c 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -11,11 +11,19 @@
 #include <linux/cpuidle.h>
 #include <linux/cpu.h>
 #include <linux/notifier.h>
+#include <linux/clockchips.h>
+#include <linux/of.h>
 
 #include <asm/machdep.h>
 #include <asm/firmware.h>
 #include <asm/runlatch.h>
 
+/* Flags and constants used in PowerNV platform */
+
+#define MAX_POWERNV_IDLE_STATES	8
+#define IDLE_USE_INST_NAP	0x00010000 /* Use nap instruction */
+#define IDLE_USE_INST_SLEEP	0x00020000 /* Use sleep instruction */
+
 struct cpuidle_driver powernv_idle_driver = {
 	.name             = "powernv_idle",
 	.owner            = THIS_MODULE,
@@ -54,10 +62,36 @@ static int nap_loop(struct cpuidle_device *dev,
 	return index;
 }
 
+static int fastsleep_loop(struct cpuidle_device *dev,
+				struct cpuidle_driver *drv,
+				int index)
+{
+	unsigned long old_lpcr = mfspr(SPRN_LPCR);
+	unsigned long new_lpcr;
+
+	if (unlikely(system_state < SYSTEM_RUNNING))
+		return index;
+
+	new_lpcr = old_lpcr;
+	new_lpcr &= ~(LPCR_MER | LPCR_PECE); /* lpcr[mer] must be 0 */
+
+	/* exit powersave upon external interrupt, but not decrementer
+	 * interrupt.
+	 */
+	new_lpcr |= LPCR_PECE0;
+
+	mtspr(SPRN_LPCR, new_lpcr);
+	power7_sleep();
+
+	mtspr(SPRN_LPCR, old_lpcr);
+
+	return index;
+}
+
 /*
  * States for dedicated partition case.
  */
-static struct cpuidle_state powernv_states[] = {
+static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
 	{ /* Snooze */
 		.name = "snooze",
 		.desc = "snooze",
@@ -65,13 +99,6 @@ static struct cpuidle_state powernv_states[] = {
 		.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,
@@ -132,19 +159,74 @@ static int powernv_cpuidle_driver_init(void)
 	return 0;
 }
 
+static int powernv_add_idle_states(void)
+{
+	struct device_node *power_mgt;
+	struct property *prop;
+	int nr_idle_states = 1; /* Snooze */
+	int dt_idle_states;
+	u32 *flags;
+	int i;
+
+	/* Currently we have snooze statically defined */
+
+	power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
+	if (!power_mgt) {
+		pr_warn("opal: PowerMgmt Node not found\n");
+		return nr_idle_states;
+	}
+
+	prop = of_find_property(power_mgt, "ibm,cpu-idle-state-flags", NULL);
+	if (!prop) {
+		pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
+		return nr_idle_states;
+	}
+
+	dt_idle_states = prop->length / sizeof(u32);
+	flags = (u32 *) prop->value;
+
+	for (i = 0; i < dt_idle_states; i++) {
+
+		if (flags[i] & IDLE_USE_INST_NAP) {
+			/* Add NAP state */
+			strcpy(powernv_states[nr_idle_states].name, "Nap");
+			strcpy(powernv_states[nr_idle_states].desc, "Nap");
+			powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID;
+			powernv_states[nr_idle_states].exit_latency = 10;
+			powernv_states[nr_idle_states].target_residency = 100;
+			powernv_states[nr_idle_states].enter = &nap_loop;
+			nr_idle_states++;
+		}
+
+		if (flags[i] & IDLE_USE_INST_SLEEP) {
+			/* Add FASTSLEEP state */
+			strcpy(powernv_states[nr_idle_states].name, "FastSleep");
+			strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
+			powernv_states[nr_idle_states].flags =
+				CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TIMER_STOP;
+			powernv_states[nr_idle_states].exit_latency = 300;
+			powernv_states[nr_idle_states].target_residency = 1000000;
+			powernv_states[nr_idle_states].enter = &fastsleep_loop;
+			nr_idle_states++;
+		}
+	}
+
+	return nr_idle_states;
+}
+
 /*
  * 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);
+		/* Device tree can indicate more idle states */
+		max_idle_state = powernv_add_idle_states();
  	} else
  		return -ENODEV;