Add deep idle states such as nap and fast sleep to the cpuidle state table
only if they are discovered from the device tree during cpuidle initialization.
Signed-off-by: Preeti U. Murthy <pre...@linux.vnet.ibm.com>
---
drivers/cpuidle/cpuidle-powerpc-book3s.c | 81 ++++++++++++++++++++++++------
1 file changed, 64 insertions(+), 17 deletions(-)
diff --git a/drivers/cpuidle/cpuidle-powerpc-book3s.c
b/drivers/cpuidle/cpuidle-powerpc-book3s.c
index 59cd529..b80ee9b 100644
--- a/drivers/cpuidle/cpuidle-powerpc-book3s.c
+++ b/drivers/cpuidle/cpuidle-powerpc-book3s.c
@@ -18,6 +18,7 @@
#include <linux/ktime.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
+#include <linux/of.h>
#include <asm/paca.h>
#include <asm/reg.h>
@@ -27,6 +28,12 @@
#include <asm/time.h>
#include <asm/plpar_wrappers.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 powerpc_book3s_idle_driver = {
.name = "powerpc_book3s_idle",
.owner = THIS_MODULE,
@@ -327,7 +334,7 @@ static struct cpuidle_state shared_states[] = {
.enter = &shared_cede_loop },
};
-static struct cpuidle_state powernv_states[] = {
+static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
{ /* Snooze */
.name = "snooze",
.desc = "snooze",
@@ -335,20 +342,6 @@ 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 },
- { /* Fastsleep */
- .name = "fastsleep",
- .desc = "fastsleep",
- .flags = CPUIDLE_FLAG_TIME_VALID,
- .exit_latency = 10,
- .target_residency = 100,
- .enter = &fastsleep_loop },
};
void update_smt_snooze_delay(int cpu, int residency)
@@ -418,6 +411,60 @@ static struct notifier_block setup_hotplug_notifier = {
.notifier_call = powerpc_book3s_cpuidle_add_cpu_notifier,
};
+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;
+ 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;
+}
+
/*
* powerpc_book3s_cpuidle_driver_init()
*/
@@ -448,7 +495,6 @@ static int powerpc_book3s_cpuidle_driver_init(void)
*/
static int powerpc_book3s_idle_probe(void)
{
-
if (cpuidle_disable != IDLE_NO_OVERRIDE)
return -ENODEV;
@@ -463,7 +509,8 @@ static int powerpc_book3s_idle_probe(void)
} else 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;
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