Re: [PATCH v6 10/11] cpuidle/powernv: Add support for POWER ISA v3 idle states

[Benjamin Herrenschmidt]

On Wed, 2016-06-08 at 11:54 -0500, Shreyas B. Prabhu wrote:
> 
> Â/*
> Â * States for dedicated partition case.
> Â */
> @@ -167,6 +183,8 @@ static int powernv_add_idle_states(void)
> Â	int nr_idle_states = 1; /* Snooze */
> Â	int dt_idle_states;
> Â	u32 *latency_ns, *residency_ns, *flags;
> +	u64 *psscr_val = NULL;
> +	const char *names[CPUIDLE_STATE_MAX];
> Â	int i, rc;
> Â
> Â	/* Currently we have snooze statically defined */
> @@ -199,12 +217,41 @@ static int powernv_add_idle_states(void)
> Â		goto out_free_latency;
> Â	}
> Â
> +	rc = of_property_read_string_array(power_mgt,
> +					ÂÂÂ"ibm,cpu-idle-state-names", names,
> +					ÂÂÂdt_idle_states);

Ok so from this I assume that dt_idle_states is the number of entries,
which has been checked properly to be <ÂCPUIDLE_STATE_MAX correct ?

Beause ...

> +	if (rc < 0) {
> +		pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
> +		goto out_free_latency;
> +	}
> +
> +	/*
> +	Â* If the idle states use stop instruction, probe for psscr values
> +	Â* which are necessary to specify required stop level.
> +	Â*/
> +	if (flags[0] & (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP)) {
> +		psscr_val = kcalloc(dt_idle_states, sizeof(*psscr_val),
> +				ÂÂÂÂGFP_KERNEL);
> +		rc = of_property_read_u64_array(power_mgt,
> +						"ibm,cpu-idle-state-psscr",
> +						psscr_val, dt_idle_states);

Here, psscr val is only one u64 ... shouldn't you kmalloc sizeof(..) *
dt_idle_states ?

> +		if (rc) {
> +			pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n");
> +			goto out_free_psscr;
> +		}
> +	}
> Â	residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL);

Just like we do here

> Â	rc = of_property_read_u32_array(power_mgt,Â		"ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
> Â	for (i = 0; i < dt_idle_states; i++) {
> -
> +		/*
> +		Â* If an idle state has exit latency beyond
> +		Â* POWERNV_THRESHOLD_LATENCY_NS then don't use it
> +		Â* in cpu-idle.
> +		Â*/
> +		if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
> +			continue;
> Â		/*
> Â		Â* Cpuidle accepts exit_latency and target_residency in us.
> Â		Â* Use default target_residency values if f/w does not expose it.
> @@ -216,6 +263,16 @@ static int powernv_add_idle_states(void)
> Â			powernv_states[nr_idle_states].flags = 0;
> Â			powernv_states[nr_idle_states].target_residency = 100;
> Â			powernv_states[nr_idle_states].enter = &nap_loop;
> +		} else if ((flags[i] & OPAL_PM_STOP_INST_FAST) &&
> +				!(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
> +			strncpy(powernv_states[nr_idle_states].name,
> +				names[i], CPUIDLE_NAME_LEN);
> +			strncpy(powernv_states[nr_idle_states].desc,
> +				names[i], CPUIDLE_NAME_LEN);
> +			powernv_states[nr_idle_states].flags = 0;
> +
> +			powernv_states[nr_idle_states].enter = stop_loop;
> +			stop_psscr_table[nr_idle_states] = psscr_val[i];
> Â		}
> Â
> Â		/*
> @@ -231,6 +288,16 @@ static int powernv_add_idle_states(void)
> Â			powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
> Â			powernv_states[nr_idle_states].target_residency = 300000;
> Â			powernv_states[nr_idle_states].enter = &fastsleep_loop;
> +		} else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) &&
> +				(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
> +			strncpy(powernv_states[nr_idle_states].name,
> +				names[i], CPUIDLE_NAME_LEN);
> +			strncpy(powernv_states[nr_idle_states].desc,
> +				names[i], CPUIDLE_NAME_LEN);
> +
> +			powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
> +			powernv_states[nr_idle_states].enter = stop_loop;
> +			stop_psscr_table[nr_idle_states] = psscr_val[i];
> Â		}
> Â#endif
> Â		powernv_states[nr_idle_states].exit_latency =
> @@ -245,6 +312,8 @@ static int powernv_add_idle_states(void)
> Â	}
> Â
> Â	kfree(residency_ns);
> +out_free_psscr:
> +	kfree(psscr_val);
> Âout_free_latency:
> Â	kfree(latency_ns);
> Âout_free_flags: