Re: [PATCH v2 2/3] cpuidle:powernv: Add helper function to populate powernv idle states.

[Gautham R Shenoy]

Hi Oliver,

Thanks for reviewing the patch!

On Tue, Nov 01, 2016 at 07:32:58PM +1100, Oliver O'Halloran wrote:
> On Thu, Oct 27, 2016 at 7:35 PM, Gautham R. Shenoy
>  wrote:
> > From: "Gautham R. Shenoy" 
> >
> > In the current code for powernv_add_idle_states, there is a lot of code
> > duplication while initializing an idle state in powernv_states table.
> >
> > Add an inline helper function to populate the powernv_states[] table for
> > a given idle state. Invoke this for populating the "Nap", "Fastsleep"
> > and the stop states in powernv_add_idle_states.
> >
> > Signed-off-by: Gautham R. Shenoy 
> > ---
> >  drivers/cpuidle/cpuidle-powernv.c | 82 
> > +++
> >  include/linux/cpuidle.h   |  1 +
> >  2 files changed, 49 insertions(+), 34 deletions(-)
> >
> > diff --git a/drivers/cpuidle/cpuidle-powernv.c 
> > b/drivers/cpuidle/cpuidle-powernv.c
> > index 7fe442c..11b22b9 100644
> > --- a/drivers/cpuidle/cpuidle-powernv.c
> > +++ b/drivers/cpuidle/cpuidle-powernv.c
> > @@ -167,6 +167,28 @@ static int powernv_cpuidle_driver_init(void)
> > return 0;
> >  }
> >
> > +static inline void add_powernv_state(int index, const char *name,
> > +unsigned int flags,
> > +int (*idle_fn)(struct cpuidle_device *,
> > +   struct cpuidle_driver *,
> > +   int),
> > +unsigned int target_residency,
> > +unsigned int exit_latency,
> > +u64 psscr_val)
> > +{
> > +   strncpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
> > +   strncpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
> 
> If the supplied name is equal to CPUIDLE_NAME_LEN then strncpy() won't
> terminate the string. The least annoying fix is to memset() the whole
> structure to zero and set n to CPUIDLE_NAME_LEN - 1.

I will change this to use strlcpy as Paul suggested in the reply.

> 
> > +   powernv_states[index].flags = flags;
> > +   powernv_states[index].target_residency = target_residency;
> > +   powernv_states[index].exit_latency = exit_latency;
> > +   powernv_states[index].enter = idle_fn;
> > +
> > +   if (idle_fn != stop_loop)
> > +   return;
> 
> This can probably be deleted. The nap/sleep loops don't look at the
> psscr setting and you've passed in a dummy value of zero anyway.

The subsequent patch adds the missing bits to the psscr_val if we are
running on the older firmware. But in any case, as you rightly pointed
out we don't use psscr_table in nap/sleep loops. So this can go.

> 
> > +
> > +   stop_psscr_table[index] = psscr_val;
> > +}
> > +
> >  static int powernv_add_idle_states(void)
> >  {
> > struct device_node *power_mgt;
> > @@ -236,6 +258,7 @@ static int powernv_add_idle_states(void)
> > "ibm,cpu-idle-state-residency-ns", residency_ns, 
> > dt_idle_states);
> >
> > for (i = 0; i < dt_idle_states; i++) {
> > +   unsigned int exit_latency, target_residency;
> > /*
> >  * If an idle state has exit latency beyond
> >  * POWERNV_THRESHOLD_LATENCY_NS then don't use it
> > @@ -244,27 +267,30 @@ static int powernv_add_idle_states(void)
> > if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
> > continue;
> >
> > +   exit_latency = ((unsigned int)latency_ns[i]) / 1000;
> > +   target_residency = (!rc) ? ((unsigned int)residency_ns[i]) 
> > : 0;
> > +   /*
> > +* Firmware passes residency values in ns.
> > +* cpuidle expects it in us.
> > +*/
> > +   target_residency /= 1000;
> > +
> > /*
> >  * Cpuidle accepts exit_latency and target_residency in us.
> 
> This comment says the same thing as the one above.

Will clean this up to reflect the state of the code.

> 
> >  * Use default target_residency values if f/w does not 
> > expose it.
> >  */
> > if (flags[i] & OPAL_PM_NAP_ENABLED) {
> > +   target_residency = 100;
> 
> Hmm, the above comment says that we should only use the default value
> for target_residency if firmware hasn't provided a value. Is there a
> reason we always use the hard coded value?

Ah, good catch! I should be setting target_residency to the default
value only if it is not set by the firmware. Will fix this.


> 
> > /* Add NAP state */
> > -   strcpy(powernv_states[nr_idle_states].name, "Nap");
> > -   strcpy(powernv_states[nr_idle_states].desc, "Nap");
> > -   

Re: [PATCH v2 2/3] cpuidle:powernv: Add helper function to populate powernv idle states.

[Gautham R Shenoy]

Hi Oliver,

Thanks for reviewing the patch!

On Tue, Nov 01, 2016 at 07:32:58PM +1100, Oliver O'Halloran wrote:
> On Thu, Oct 27, 2016 at 7:35 PM, Gautham R. Shenoy
>  wrote:
> > From: "Gautham R. Shenoy" 
> >
> > In the current code for powernv_add_idle_states, there is a lot of code
> > duplication while initializing an idle state in powernv_states table.
> >
> > Add an inline helper function to populate the powernv_states[] table for
> > a given idle state. Invoke this for populating the "Nap", "Fastsleep"
> > and the stop states in powernv_add_idle_states.
> >
> > Signed-off-by: Gautham R. Shenoy 
> > ---
> >  drivers/cpuidle/cpuidle-powernv.c | 82 
> > +++
> >  include/linux/cpuidle.h   |  1 +
> >  2 files changed, 49 insertions(+), 34 deletions(-)
> >
> > diff --git a/drivers/cpuidle/cpuidle-powernv.c 
> > b/drivers/cpuidle/cpuidle-powernv.c
> > index 7fe442c..11b22b9 100644
> > --- a/drivers/cpuidle/cpuidle-powernv.c
> > +++ b/drivers/cpuidle/cpuidle-powernv.c
> > @@ -167,6 +167,28 @@ static int powernv_cpuidle_driver_init(void)
> > return 0;
> >  }
> >
> > +static inline void add_powernv_state(int index, const char *name,
> > +unsigned int flags,
> > +int (*idle_fn)(struct cpuidle_device *,
> > +   struct cpuidle_driver *,
> > +   int),
> > +unsigned int target_residency,
> > +unsigned int exit_latency,
> > +u64 psscr_val)
> > +{
> > +   strncpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
> > +   strncpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
> 
> If the supplied name is equal to CPUIDLE_NAME_LEN then strncpy() won't
> terminate the string. The least annoying fix is to memset() the whole
> structure to zero and set n to CPUIDLE_NAME_LEN - 1.

I will change this to use strlcpy as Paul suggested in the reply.

> 
> > +   powernv_states[index].flags = flags;
> > +   powernv_states[index].target_residency = target_residency;
> > +   powernv_states[index].exit_latency = exit_latency;
> > +   powernv_states[index].enter = idle_fn;
> > +
> > +   if (idle_fn != stop_loop)
> > +   return;
> 
> This can probably be deleted. The nap/sleep loops don't look at the
> psscr setting and you've passed in a dummy value of zero anyway.

The subsequent patch adds the missing bits to the psscr_val if we are
running on the older firmware. But in any case, as you rightly pointed
out we don't use psscr_table in nap/sleep loops. So this can go.

> 
> > +
> > +   stop_psscr_table[index] = psscr_val;
> > +}
> > +
> >  static int powernv_add_idle_states(void)
> >  {
> > struct device_node *power_mgt;
> > @@ -236,6 +258,7 @@ static int powernv_add_idle_states(void)
> > "ibm,cpu-idle-state-residency-ns", residency_ns, 
> > dt_idle_states);
> >
> > for (i = 0; i < dt_idle_states; i++) {
> > +   unsigned int exit_latency, target_residency;
> > /*
> >  * If an idle state has exit latency beyond
> >  * POWERNV_THRESHOLD_LATENCY_NS then don't use it
> > @@ -244,27 +267,30 @@ static int powernv_add_idle_states(void)
> > if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
> > continue;
> >
> > +   exit_latency = ((unsigned int)latency_ns[i]) / 1000;
> > +   target_residency = (!rc) ? ((unsigned int)residency_ns[i]) 
> > : 0;
> > +   /*
> > +* Firmware passes residency values in ns.
> > +* cpuidle expects it in us.
> > +*/
> > +   target_residency /= 1000;
> > +
> > /*
> >  * Cpuidle accepts exit_latency and target_residency in us.
> 
> This comment says the same thing as the one above.

Will clean this up to reflect the state of the code.

> 
> >  * Use default target_residency values if f/w does not 
> > expose it.
> >  */
> > if (flags[i] & OPAL_PM_NAP_ENABLED) {
> > +   target_residency = 100;
> 
> Hmm, the above comment says that we should only use the default value
> for target_residency if firmware hasn't provided a value. Is there a
> reason we always use the hard coded value?

Ah, good catch! I should be setting target_residency to the default
value only if it is not set by the firmware. Will fix this.


> 
> > /* 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;
> > -   

Re: [PATCH v2 2/3] cpuidle:powernv: Add helper function to populate powernv idle states.

[Paul Mackerras]

On Tue, Nov 01, 2016 at 07:32:58PM +1100, Oliver O'Halloran wrote:
> On Thu, Oct 27, 2016 at 7:35 PM, Gautham R. Shenoy
>  wrote:
> > From: "Gautham R. Shenoy" 
> >
> > In the current code for powernv_add_idle_states, there is a lot of code
> > duplication while initializing an idle state in powernv_states table.
> >
> > Add an inline helper function to populate the powernv_states[] table for
> > a given idle state. Invoke this for populating the "Nap", "Fastsleep"
> > and the stop states in powernv_add_idle_states.
> >
> > Signed-off-by: Gautham R. Shenoy 
> > ---
> >  drivers/cpuidle/cpuidle-powernv.c | 82 
> > +++
> >  include/linux/cpuidle.h   |  1 +
> >  2 files changed, 49 insertions(+), 34 deletions(-)
> >
> > diff --git a/drivers/cpuidle/cpuidle-powernv.c 
> > b/drivers/cpuidle/cpuidle-powernv.c
> > index 7fe442c..11b22b9 100644
> > --- a/drivers/cpuidle/cpuidle-powernv.c
> > +++ b/drivers/cpuidle/cpuidle-powernv.c
> > @@ -167,6 +167,28 @@ static int powernv_cpuidle_driver_init(void)
> > return 0;
> >  }
> >
> > +static inline void add_powernv_state(int index, const char *name,
> > +unsigned int flags,
> > +int (*idle_fn)(struct cpuidle_device *,
> > +   struct cpuidle_driver *,
> > +   int),
> > +unsigned int target_residency,
> > +unsigned int exit_latency,
> > +u64 psscr_val)
> > +{
> > +   strncpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
> > +   strncpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
> 
> If the supplied name is equal to CPUIDLE_NAME_LEN then strncpy() won't
> terminate the string. The least annoying fix is to memset() the whole
> structure to zero and set n to CPUIDLE_NAME_LEN - 1.

Or he could use strlcpy() instead of strncpy().

Paul.

Re: [PATCH v2 2/3] cpuidle:powernv: Add helper function to populate powernv idle states.

[Paul Mackerras]

On Tue, Nov 01, 2016 at 07:32:58PM +1100, Oliver O'Halloran wrote:
> On Thu, Oct 27, 2016 at 7:35 PM, Gautham R. Shenoy
>  wrote:
> > From: "Gautham R. Shenoy" 
> >
> > In the current code for powernv_add_idle_states, there is a lot of code
> > duplication while initializing an idle state in powernv_states table.
> >
> > Add an inline helper function to populate the powernv_states[] table for
> > a given idle state. Invoke this for populating the "Nap", "Fastsleep"
> > and the stop states in powernv_add_idle_states.
> >
> > Signed-off-by: Gautham R. Shenoy 
> > ---
> >  drivers/cpuidle/cpuidle-powernv.c | 82 
> > +++
> >  include/linux/cpuidle.h   |  1 +
> >  2 files changed, 49 insertions(+), 34 deletions(-)
> >
> > diff --git a/drivers/cpuidle/cpuidle-powernv.c 
> > b/drivers/cpuidle/cpuidle-powernv.c
> > index 7fe442c..11b22b9 100644
> > --- a/drivers/cpuidle/cpuidle-powernv.c
> > +++ b/drivers/cpuidle/cpuidle-powernv.c
> > @@ -167,6 +167,28 @@ static int powernv_cpuidle_driver_init(void)
> > return 0;
> >  }
> >
> > +static inline void add_powernv_state(int index, const char *name,
> > +unsigned int flags,
> > +int (*idle_fn)(struct cpuidle_device *,
> > +   struct cpuidle_driver *,
> > +   int),
> > +unsigned int target_residency,
> > +unsigned int exit_latency,
> > +u64 psscr_val)
> > +{
> > +   strncpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
> > +   strncpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
> 
> If the supplied name is equal to CPUIDLE_NAME_LEN then strncpy() won't
> terminate the string. The least annoying fix is to memset() the whole
> structure to zero and set n to CPUIDLE_NAME_LEN - 1.

Or he could use strlcpy() instead of strncpy().

Paul.

Re: [PATCH v2 2/3] cpuidle:powernv: Add helper function to populate powernv idle states.

[Oliver O'Halloran]

On Thu, Oct 27, 2016 at 7:35 PM, Gautham R. Shenoy
 wrote:
> From: "Gautham R. Shenoy" 
>
> In the current code for powernv_add_idle_states, there is a lot of code
> duplication while initializing an idle state in powernv_states table.
>
> Add an inline helper function to populate the powernv_states[] table for
> a given idle state. Invoke this for populating the "Nap", "Fastsleep"
> and the stop states in powernv_add_idle_states.
>
> Signed-off-by: Gautham R. Shenoy 
> ---
>  drivers/cpuidle/cpuidle-powernv.c | 82 
> +++
>  include/linux/cpuidle.h   |  1 +
>  2 files changed, 49 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-powernv.c 
> b/drivers/cpuidle/cpuidle-powernv.c
> index 7fe442c..11b22b9 100644
> --- a/drivers/cpuidle/cpuidle-powernv.c
> +++ b/drivers/cpuidle/cpuidle-powernv.c
> @@ -167,6 +167,28 @@ static int powernv_cpuidle_driver_init(void)
> return 0;
>  }
>
> +static inline void add_powernv_state(int index, const char *name,
> +unsigned int flags,
> +int (*idle_fn)(struct cpuidle_device *,
> +   struct cpuidle_driver *,
> +   int),
> +unsigned int target_residency,
> +unsigned int exit_latency,
> +u64 psscr_val)
> +{
> +   strncpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
> +   strncpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);

If the supplied name is equal to CPUIDLE_NAME_LEN then strncpy() won't
terminate the string. The least annoying fix is to memset() the whole
structure to zero and set n to CPUIDLE_NAME_LEN - 1.

> +   powernv_states[index].flags = flags;
> +   powernv_states[index].target_residency = target_residency;
> +   powernv_states[index].exit_latency = exit_latency;
> +   powernv_states[index].enter = idle_fn;
> +
> +   if (idle_fn != stop_loop)
> +   return;

This can probably be deleted. The nap/sleep loops don't look at the
psscr setting and you've passed in a dummy value of zero anyway.

> +
> +   stop_psscr_table[index] = psscr_val;
> +}
> +
>  static int powernv_add_idle_states(void)
>  {
> struct device_node *power_mgt;
> @@ -236,6 +258,7 @@ static int powernv_add_idle_states(void)
> "ibm,cpu-idle-state-residency-ns", residency_ns, 
> dt_idle_states);
>
> for (i = 0; i < dt_idle_states; i++) {
> +   unsigned int exit_latency, target_residency;
> /*
>  * If an idle state has exit latency beyond
>  * POWERNV_THRESHOLD_LATENCY_NS then don't use it
> @@ -244,27 +267,30 @@ static int powernv_add_idle_states(void)
> if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
> continue;
>
> +   exit_latency = ((unsigned int)latency_ns[i]) / 1000;
> +   target_residency = (!rc) ? ((unsigned int)residency_ns[i]) : 
> 0;
> +   /*
> +* Firmware passes residency values in ns.
> +* cpuidle expects it in us.
> +*/
> +   target_residency /= 1000;
> +
> /*
>  * Cpuidle accepts exit_latency and target_residency in us.

This comment says the same thing as the one above.

>  * Use default target_residency values if f/w does not expose 
> it.
>  */
> if (flags[i] & OPAL_PM_NAP_ENABLED) {
> +   target_residency = 100;

Hmm, the above comment says that we should only use the default value
for target_residency if firmware hasn't provided a value. Is there a
reason we always use the hard coded value?

> /* 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].target_residency = 100;
> -   powernv_states[nr_idle_states].enter = nap_loop;
> +   add_powernv_state(nr_idle_states, "Nap",
> + CPUIDLE_FLAG_NONE, nap_loop,
> + target_residency, exit_latency, 0);
> } 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,
> -  

Re: [PATCH v2 2/3] cpuidle:powernv: Add helper function to populate powernv idle states.

[Oliver O'Halloran]

On Thu, Oct 27, 2016 at 7:35 PM, Gautham R. Shenoy
 wrote:
> From: "Gautham R. Shenoy" 
>
> In the current code for powernv_add_idle_states, there is a lot of code
> duplication while initializing an idle state in powernv_states table.
>
> Add an inline helper function to populate the powernv_states[] table for
> a given idle state. Invoke this for populating the "Nap", "Fastsleep"
> and the stop states in powernv_add_idle_states.
>
> Signed-off-by: Gautham R. Shenoy 
> ---
>  drivers/cpuidle/cpuidle-powernv.c | 82 
> +++
>  include/linux/cpuidle.h   |  1 +
>  2 files changed, 49 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-powernv.c 
> b/drivers/cpuidle/cpuidle-powernv.c
> index 7fe442c..11b22b9 100644
> --- a/drivers/cpuidle/cpuidle-powernv.c
> +++ b/drivers/cpuidle/cpuidle-powernv.c
> @@ -167,6 +167,28 @@ static int powernv_cpuidle_driver_init(void)
> return 0;
>  }
>
> +static inline void add_powernv_state(int index, const char *name,
> +unsigned int flags,
> +int (*idle_fn)(struct cpuidle_device *,
> +   struct cpuidle_driver *,
> +   int),
> +unsigned int target_residency,
> +unsigned int exit_latency,
> +u64 psscr_val)
> +{
> +   strncpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
> +   strncpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);

If the supplied name is equal to CPUIDLE_NAME_LEN then strncpy() won't
terminate the string. The least annoying fix is to memset() the whole
structure to zero and set n to CPUIDLE_NAME_LEN - 1.

> +   powernv_states[index].flags = flags;
> +   powernv_states[index].target_residency = target_residency;
> +   powernv_states[index].exit_latency = exit_latency;
> +   powernv_states[index].enter = idle_fn;
> +
> +   if (idle_fn != stop_loop)
> +   return;

This can probably be deleted. The nap/sleep loops don't look at the
psscr setting and you've passed in a dummy value of zero anyway.

> +
> +   stop_psscr_table[index] = psscr_val;
> +}
> +
>  static int powernv_add_idle_states(void)
>  {
> struct device_node *power_mgt;
> @@ -236,6 +258,7 @@ static int powernv_add_idle_states(void)
> "ibm,cpu-idle-state-residency-ns", residency_ns, 
> dt_idle_states);
>
> for (i = 0; i < dt_idle_states; i++) {
> +   unsigned int exit_latency, target_residency;
> /*
>  * If an idle state has exit latency beyond
>  * POWERNV_THRESHOLD_LATENCY_NS then don't use it
> @@ -244,27 +267,30 @@ static int powernv_add_idle_states(void)
> if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
> continue;
>
> +   exit_latency = ((unsigned int)latency_ns[i]) / 1000;
> +   target_residency = (!rc) ? ((unsigned int)residency_ns[i]) : 
> 0;
> +   /*
> +* Firmware passes residency values in ns.
> +* cpuidle expects it in us.
> +*/
> +   target_residency /= 1000;
> +
> /*
>  * Cpuidle accepts exit_latency and target_residency in us.

This comment says the same thing as the one above.

>  * Use default target_residency values if f/w does not expose 
> it.
>  */
> if (flags[i] & OPAL_PM_NAP_ENABLED) {
> +   target_residency = 100;

Hmm, the above comment says that we should only use the default value
for target_residency if firmware hasn't provided a value. Is there a
reason we always use the hard coded value?

> /* 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].target_residency = 100;
> -   powernv_states[nr_idle_states].enter = nap_loop;
> +   add_powernv_state(nr_idle_states, "Nap",
> + CPUIDLE_FLAG_NONE, nap_loop,
> + target_residency, exit_latency, 0);
> } 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);
> -   

[PATCH v2 2/3] cpuidle:powernv: Add helper function to populate powernv idle states.

[Gautham R. Shenoy]

From: "Gautham R. Shenoy" 

In the current code for powernv_add_idle_states, there is a lot of code
duplication while initializing an idle state in powernv_states table.

Add an inline helper function to populate the powernv_states[] table for
a given idle state. Invoke this for populating the "Nap", "Fastsleep"
and the stop states in powernv_add_idle_states.

Signed-off-by: Gautham R. Shenoy 
---
 drivers/cpuidle/cpuidle-powernv.c | 82 +++
 include/linux/cpuidle.h   |  1 +
 2 files changed, 49 insertions(+), 34 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-powernv.c 
b/drivers/cpuidle/cpuidle-powernv.c
index 7fe442c..11b22b9 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -167,6 +167,28 @@ static int powernv_cpuidle_driver_init(void)
return 0;
 }
 
+static inline void add_powernv_state(int index, const char *name,
+unsigned int flags,
+int (*idle_fn)(struct cpuidle_device *,
+   struct cpuidle_driver *,
+   int),
+unsigned int target_residency,
+unsigned int exit_latency,
+u64 psscr_val)
+{
+   strncpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
+   strncpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
+   powernv_states[index].flags = flags;
+   powernv_states[index].target_residency = target_residency;
+   powernv_states[index].exit_latency = exit_latency;
+   powernv_states[index].enter = idle_fn;
+
+   if (idle_fn != stop_loop)
+   return;
+
+   stop_psscr_table[index] = psscr_val;
+}
+
 static int powernv_add_idle_states(void)
 {
struct device_node *power_mgt;
@@ -236,6 +258,7 @@ static int powernv_add_idle_states(void)
"ibm,cpu-idle-state-residency-ns", residency_ns, 
dt_idle_states);
 
for (i = 0; i < dt_idle_states; i++) {
+   unsigned int exit_latency, target_residency;
/*
 * If an idle state has exit latency beyond
 * POWERNV_THRESHOLD_LATENCY_NS then don't use it
@@ -244,27 +267,30 @@ static int powernv_add_idle_states(void)
if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
continue;
 
+   exit_latency = ((unsigned int)latency_ns[i]) / 1000;
+   target_residency = (!rc) ? ((unsigned int)residency_ns[i]) : 0;
+   /*
+* Firmware passes residency values in ns.
+* cpuidle expects it in us.
+*/
+   target_residency /= 1000;
+
/*
 * Cpuidle accepts exit_latency and target_residency in us.
 * Use default target_residency values if f/w does not expose 
it.
 */
if (flags[i] & OPAL_PM_NAP_ENABLED) {
+   target_residency = 100;
/* 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].target_residency = 100;
-   powernv_states[nr_idle_states].enter = nap_loop;
+   add_powernv_state(nr_idle_states, "Nap",
+ CPUIDLE_FLAG_NONE, nap_loop,
+ target_residency, exit_latency, 0);
} 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];
+   add_powernv_state(nr_idle_states, names[i],
+ CPUIDLE_FLAG_NONE, stop_loop,
+ target_residency, exit_latency,
+ psscr_val[i]);
}
 
/*
@@ -274,32 +300,20 @@ static int powernv_add_idle_states(void)
 #ifdef CONFIG_TICK_ONESHOT
if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
+   target_residency = 30;
   

[PATCH v2 2/3] cpuidle:powernv: Add helper function to populate powernv idle states.

[Gautham R. Shenoy]

From: "Gautham R. Shenoy" 

In the current code for powernv_add_idle_states, there is a lot of code
duplication while initializing an idle state in powernv_states table.

Add an inline helper function to populate the powernv_states[] table for
a given idle state. Invoke this for populating the "Nap", "Fastsleep"
and the stop states in powernv_add_idle_states.

Signed-off-by: Gautham R. Shenoy 
---
 drivers/cpuidle/cpuidle-powernv.c | 82 +++
 include/linux/cpuidle.h   |  1 +
 2 files changed, 49 insertions(+), 34 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-powernv.c 
b/drivers/cpuidle/cpuidle-powernv.c
index 7fe442c..11b22b9 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -167,6 +167,28 @@ static int powernv_cpuidle_driver_init(void)
return 0;
 }
 
+static inline void add_powernv_state(int index, const char *name,
+unsigned int flags,
+int (*idle_fn)(struct cpuidle_device *,
+   struct cpuidle_driver *,
+   int),
+unsigned int target_residency,
+unsigned int exit_latency,
+u64 psscr_val)
+{
+   strncpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
+   strncpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
+   powernv_states[index].flags = flags;
+   powernv_states[index].target_residency = target_residency;
+   powernv_states[index].exit_latency = exit_latency;
+   powernv_states[index].enter = idle_fn;
+
+   if (idle_fn != stop_loop)
+   return;
+
+   stop_psscr_table[index] = psscr_val;
+}
+
 static int powernv_add_idle_states(void)
 {
struct device_node *power_mgt;
@@ -236,6 +258,7 @@ static int powernv_add_idle_states(void)
"ibm,cpu-idle-state-residency-ns", residency_ns, 
dt_idle_states);
 
for (i = 0; i < dt_idle_states; i++) {
+   unsigned int exit_latency, target_residency;
/*
 * If an idle state has exit latency beyond
 * POWERNV_THRESHOLD_LATENCY_NS then don't use it
@@ -244,27 +267,30 @@ static int powernv_add_idle_states(void)
if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
continue;
 
+   exit_latency = ((unsigned int)latency_ns[i]) / 1000;
+   target_residency = (!rc) ? ((unsigned int)residency_ns[i]) : 0;
+   /*
+* Firmware passes residency values in ns.
+* cpuidle expects it in us.
+*/
+   target_residency /= 1000;
+
/*
 * Cpuidle accepts exit_latency and target_residency in us.
 * Use default target_residency values if f/w does not expose 
it.
 */
if (flags[i] & OPAL_PM_NAP_ENABLED) {
+   target_residency = 100;
/* 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].target_residency = 100;
-   powernv_states[nr_idle_states].enter = nap_loop;
+   add_powernv_state(nr_idle_states, "Nap",
+ CPUIDLE_FLAG_NONE, nap_loop,
+ target_residency, exit_latency, 0);
} 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];
+   add_powernv_state(nr_idle_states, names[i],
+ CPUIDLE_FLAG_NONE, stop_loop,
+ target_residency, exit_latency,
+ psscr_val[i]);
}
 
/*
@@ -274,32 +300,20 @@ static int powernv_add_idle_states(void)
 #ifdef CONFIG_TICK_ONESHOT
if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
+   target_residency = 30;
/* Add FASTSLEEP state */
-