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Subject[PATCH v7 09/11] cpuidle/powernv: cleanup powernv_add_idle_states
Date
 - Use stack instead of kzalloc'ed memory for variables while probing
device tree for idle states.
- Set cap for number of idle states that can be added to
cpuidle_state_table
- Minor change in way we check of_property_read_u32_array for error
for sake of consistency
- Drop unnecessary "&" while assigning function pointer

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-pm@vger.kernel.org
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
---
- New in v7. This was mainly to make the existing code
consistent with the review comments for new code

drivers/cpuidle/cpuidle-powernv.c | 36 +++++++++++++++++++-----------------
1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 3a763a8..a89f546 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -166,7 +166,9 @@ static int powernv_add_idle_states(void)
struct device_node *power_mgt;
int nr_idle_states = 1; /* Snooze */
int dt_idle_states;
- u32 *latency_ns, *residency_ns, *flags;
+ u32 latency_ns[CPUIDLE_STATE_MAX];
+ u32 residency_ns[CPUIDLE_STATE_MAX];
+ u32 flags[CPUIDLE_STATE_MAX];
int i, rc;

/* Currently we have snooze statically defined */
@@ -184,22 +186,28 @@ static int powernv_add_idle_states(void)
goto out;
}

- flags = kzalloc(sizeof(*flags) * dt_idle_states, GFP_KERNEL);
+ /*
+ * Since snooze is used as first idle state, max idle states allowed is
+ * CPUIDLE_STATE_MAX -1
+ */
+ if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
+ pr_warn("cpuidle-powernv: discovered idle states more than allowed");
+ dt_idle_states = CPUIDLE_STATE_MAX - 1;
+ }
+
if (of_property_read_u32_array(power_mgt,
"ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
- goto out_free_flags;
+ goto out;
}

- 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) {
+ if (of_property_read_u32_array(power_mgt,
+ "ibm,cpu-idle-state-latencies-ns", latency_ns,
+ dt_idle_states)) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
- goto out_free_latency;
+ goto out;
}

- 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);

@@ -215,7 +223,7 @@ static int powernv_add_idle_states(void)
strcpy(powernv_states[nr_idle_states].desc, "Nap");
powernv_states[nr_idle_states].flags = 0;
powernv_states[nr_idle_states].target_residency = 100;
- powernv_states[nr_idle_states].enter = &nap_loop;
+ powernv_states[nr_idle_states].enter = nap_loop;
}

/*
@@ -230,7 +238,7 @@ static int powernv_add_idle_states(void)
strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
powernv_states[nr_idle_states].target_residency = 300000;
- powernv_states[nr_idle_states].enter = &fastsleep_loop;
+ powernv_states[nr_idle_states].enter = fastsleep_loop;
}
#endif
powernv_states[nr_idle_states].exit_latency =
@@ -243,12 +251,6 @@ static int powernv_add_idle_states(void)

nr_idle_states++;
}
-
- kfree(residency_ns);
-out_free_latency:
- kfree(latency_ns);
-out_free_flags:
- kfree(flags);
out:
return nr_idle_states;
}
--
2.4.11
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