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cpuidle/powernv: Parse device tree to setup idle states

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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 <preeti@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Preeti U Murthy 2014-02-26 05:39:20 +05:30 committed by Benjamin Herrenschmidt
parent 0d94873011
commit 0888839c5b
1 changed files with 65 additions and 17 deletions
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82
drivers/cpuidle/cpuidle-powernv.c
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@ -12,10 +12,17 @@
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/clockchips.h>
#include <linux/of.h>
#include <asm/machdep.h>
#include <asm/firmware.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,
@ -79,7 +86,7 @@ static int fastsleep_loop(struct cpuidle_device *dev,
/*
* 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",
@ -87,20 +94,6 @@ 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 },
};
static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
@ -161,19 +154,74 @@ 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;