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authorPreeti U Murthy <preeti@linux.vnet.ibm.com>2015-02-18 06:34:17 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-02-18 06:34:17 +0100
commit92c83ff5b42b109c94fdeee53cb31f674f776d75 (patch)
treee8ca5ef30cc1bd687496139d9905452798dde8c8 /drivers/cpuidle
parent5177a94aea6fbffc897aaee29c7cde57f951b541 (diff)
cpuidle: powernv: Read target_residency value of idle states from DT if available
The device tree now exposes the residency values for different idle states. Read these values instead of calculating residency from the latency values. The values exposed in the DT are validated for optimal power efficiency. However to maintain compatibility with the older firmware code which does not expose residency values, use default values as a fallback mechanism. While at it, use better APIs to parse the powermgmt device tree node. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/cpuidle-powernv.c69
1 files changed, 40 insertions, 29 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index aedec0957934..30d42298a69f 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -13,6 +13,7 @@
#include <linux/notifier.h>
#include <linux/clockchips.h>
#include <linux/of.h>
+#include <linux/slab.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
@@ -159,69 +160,79 @@ static int powernv_add_idle_states(void)
int nr_idle_states = 1; /* Snooze */
int dt_idle_states;
const __be32 *idle_state_flags;
- const __be32 *idle_state_latency;
- u32 len_flags, flags, latency_ns;
- int i;
+ u32 len_flags, flags;
+ u32 *latency_ns, *residency_ns;
+ int i, rc;
/* 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;
+ goto out;
}
- idle_state_flags = of_get_property(power_mgt, "ibm,cpu-idle-state-flags", &len_flags);
+ idle_state_flags = of_get_property(power_mgt,
+ "ibm,cpu-idle-state-flags", &len_flags);
if (!idle_state_flags) {
- pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
- return nr_idle_states;
+ pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-flags in DT\n");
+ goto out;
}
- idle_state_latency = of_get_property(power_mgt,
- "ibm,cpu-idle-state-latencies-ns", NULL);
- if (!idle_state_latency) {
- pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n");
- return nr_idle_states;
+ dt_idle_states = len_flags / sizeof(u32);
+
+ latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL);
+ rc = of_property_read_u32_array(power_mgt,
+ "ibm,cpu-idle-state-latencies-ns", latency_ns, dt_idle_states);
+ if (rc) {
+ pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
+ goto out_free_latency;
}
- dt_idle_states = len_flags / sizeof(u32);
+ residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL);
+ rc = of_property_read_u32_array(power_mgt,
+ "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
for (i = 0; i < dt_idle_states; i++) {
flags = be32_to_cpu(idle_state_flags[i]);
- /* Cpuidle accepts exit_latency in us and we estimate
- * target residency to be 10x exit_latency
+ /*
+ * Cpuidle accepts exit_latency and target_residency in us.
+ * Use default target_residency values if f/w does not expose it.
*/
- latency_ns = be32_to_cpu(idle_state_latency[i]);
if (flags & OPAL_PM_NAP_ENABLED) {
/* 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 = 0;
- powernv_states[nr_idle_states].exit_latency =
- ((unsigned int)latency_ns) / 1000;
- powernv_states[nr_idle_states].target_residency =
- ((unsigned int)latency_ns / 100);
+ powernv_states[nr_idle_states].target_residency = 100;
powernv_states[nr_idle_states].enter = &nap_loop;
- nr_idle_states++;
- }
-
- if (flags & OPAL_PM_SLEEP_ENABLED ||
+ } else if (flags & OPAL_PM_SLEEP_ENABLED ||
flags & OPAL_PM_SLEEP_ENABLED_ER1) {
/* 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_TIMER_STOP;
- powernv_states[nr_idle_states].exit_latency =
- ((unsigned int)latency_ns) / 1000;
- powernv_states[nr_idle_states].target_residency =
- ((unsigned int)latency_ns / 100);
+ powernv_states[nr_idle_states].target_residency = 300000;
powernv_states[nr_idle_states].enter = &fastsleep_loop;
- nr_idle_states++;
}
+
+ powernv_states[nr_idle_states].exit_latency =
+ ((unsigned int)latency_ns[i]) / 1000;
+
+ if (!rc) {
+ powernv_states[nr_idle_states].target_residency =
+ ((unsigned int)residency_ns[i]) / 1000;
+ }
+
+ nr_idle_states++;
}
+ kfree(residency_ns);
+out_free_latency:
+ kfree(latency_ns);
+out:
return nr_idle_states;
}