Commit 09ca4c9b authored by Akshay Adiga's avatar Akshay Adiga Committed by Rafael J. Wysocki
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cpufreq: powernv: Replacing pstate_id with frequency table index 



Refactoring code to use frequency table index instead of pstate_id.
This abstraction will make the code independent of the pstate values.

- No functional changes
- The highest frequency is at frequency table index 0 and the frequency
  decreases as the index increases.
- Macros pstates_to_idx() and idx_to_pstate() can be used for conversion
  between pstate_id and index.
- powernv_pstate_info now contains frequency table index to min, max and
  nominal frequency (instead of pstate_ids)
- global_pstate_info new stores index values instead pstate ids.
- variables renamed as *_idx which now store index instead of pstate

Signed-off-by: default avatarAkshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Reviewed-by: default avatarGautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 5fc8f707

drivers/cpufreq/powernv-cpufreq.c

+102 −75
Original line number Diff line number Diff line
@@ -64,12 +64,14 @@ 
/**

 * struct global_pstate_info -	Per policy data structure to maintain history of

 *				global pstates

 * @highest_lpstate:		The local pstate from which we are ramping down

 * @highest_lpstate_idx:	The local pstate index from which we are

 *				ramping down

 * @elapsed_time:		Time in ms spent in ramping down from

 *				highest_lpstate

 *				highest_lpstate_idx

 * @last_sampled_time:		Time from boot in ms when global pstates were

 *				last set

 * @last_lpstate,last_gpstate:	Last set values for local and global pstates

 * @last_lpstate_idx,		Last set value of local pstate and global

 * last_gpstate_idx		pstate in terms of cpufreq table index

 * @timer:			Is used for ramping down if cpu goes idle for

 *				a long time with global pstate held high

 * @gpstate_lock:		A spinlock to maintain synchronization between
@@ -77,11 +79,11 @@ 
 *				governer's target_index calls

 */

struct global_pstate_info {

	int highest_lpstate;

	int highest_lpstate_idx;

	unsigned int elapsed_time;

	unsigned int last_sampled_time;

	int last_lpstate;

	int last_gpstate;

	int last_lpstate_idx;

	int last_gpstate_idx;

	spinlock_t gpstate_lock;

	struct timer_list timer;

};
@@ -124,29 +126,47 @@ static int nr_chips; 
static DEFINE_PER_CPU(struct chip *, chip_info);



/*

 * Note: The set of pstates consists of contiguous integers, the

 * smallest of which is indicated by powernv_pstate_info.min, the

 * largest of which is indicated by powernv_pstate_info.max.

 * Note:

 * The set of pstates consists of contiguous integers.

 * powernv_pstate_info stores the index of the frequency table for

 * max, min and nominal frequencies. It also stores number of

 * available frequencies.

 *

 * The nominal pstate is the highest non-turbo pstate in this

 * platform. This is indicated by powernv_pstate_info.nominal.

 * powernv_pstate_info.nominal indicates the index to the highest

 * non-turbo frequency.

 */

static struct powernv_pstate_info {

	int min;

	int max;

	int nominal;

	int nr_pstates;

	unsigned int min;

	unsigned int max;

	unsigned int nominal;

	unsigned int nr_pstates;

} powernv_pstate_info;



/* Use following macros for conversions between pstate_id and index */

static inline int idx_to_pstate(unsigned int i)

{

	return powernv_freqs[i].driver_data;

}



static inline unsigned int pstate_to_idx(int pstate)

{

	/*

	 * abs() is deliberately used so that is works with

	 * both monotonically increasing and decreasing

	 * pstate values

	 */

	return abs(pstate - idx_to_pstate(powernv_pstate_info.max));

}



static inline void reset_gpstates(struct cpufreq_policy *policy)

{

	struct global_pstate_info *gpstates = policy->driver_data;



	gpstates->highest_lpstate = 0;

	gpstates->highest_lpstate_idx = 0;

	gpstates->elapsed_time = 0;

	gpstates->last_sampled_time = 0;

	gpstates->last_lpstate = 0;

	gpstates->last_gpstate = 0;

	gpstates->last_lpstate_idx = 0;

	gpstates->last_gpstate_idx = 0;

}



/*
@@ -156,9 +176,10 @@ static inline void reset_gpstates(struct cpufreq_policy *policy) 
static int init_powernv_pstates(void)

{

	struct device_node *power_mgt;

	int i, pstate_min, pstate_max, pstate_nominal, nr_pstates = 0;

	int i, nr_pstates = 0;

	const __be32 *pstate_ids, *pstate_freqs;

	u32 len_ids, len_freqs;

	u32 pstate_min, pstate_max, pstate_nominal;



	power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");

	if (!power_mgt) {
@@ -208,6 +229,7 @@ static int init_powernv_pstates(void) 
		return -ENODEV;

	}



	powernv_pstate_info.nr_pstates = nr_pstates;

	pr_debug("NR PStates %d\n", nr_pstates);

	for (i = 0; i < nr_pstates; i++) {

		u32 id = be32_to_cpu(pstate_ids[i]);
@@ -216,15 +238,17 @@ static int init_powernv_pstates(void) 
		pr_debug("PState id %d freq %d MHz\n", id, freq);

		powernv_freqs[i].frequency = freq * 1000; /* kHz */

		powernv_freqs[i].driver_data = id;



		if (id == pstate_max)

			powernv_pstate_info.max = i;

		else if (id == pstate_nominal)

			powernv_pstate_info.nominal = i;

		else if (id == pstate_min)

			powernv_pstate_info.min = i;

	}



	/* End of list marker entry */

	powernv_freqs[i].frequency = CPUFREQ_TABLE_END;



	powernv_pstate_info.min = pstate_min;

	powernv_pstate_info.max = pstate_max;

	powernv_pstate_info.nominal = pstate_nominal;

	powernv_pstate_info.nr_pstates = nr_pstates;



	return 0;

}
@@ -233,12 +257,12 @@ static unsigned int pstate_id_to_freq(int pstate_id) 
{

	int i;



	i = powernv_pstate_info.max - pstate_id;

	i = pstate_to_idx(pstate_id);

	if (i >= powernv_pstate_info.nr_pstates || i < 0) {

		pr_warn("PState id %d outside of PState table, "

			"reporting nominal id %d instead\n",

			pstate_id, powernv_pstate_info.nominal);

		i = powernv_pstate_info.max - powernv_pstate_info.nominal;

			pstate_id, idx_to_pstate(powernv_pstate_info.nominal));

		i = powernv_pstate_info.nominal;

	}



	return powernv_freqs[i].frequency;
@@ -252,7 +276,7 @@ static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy, 
					char *buf)

{

	return sprintf(buf, "%u\n",

		pstate_id_to_freq(powernv_pstate_info.nominal));

		powernv_freqs[powernv_pstate_info.nominal].frequency);

}



struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
@@ -426,7 +450,7 @@ static void set_pstate(void *data) 
 */

static inline unsigned int get_nominal_index(void)

{

	return powernv_pstate_info.max - powernv_pstate_info.nominal;

	return powernv_pstate_info.nominal;

}



static void powernv_cpufreq_throttle_check(void *data)
@@ -435,20 +459,22 @@ static void powernv_cpufreq_throttle_check(void *data) 
	unsigned int cpu = smp_processor_id();

	unsigned long pmsr;

	int pmsr_pmax;

	unsigned int pmsr_pmax_idx;



	pmsr = get_pmspr(SPRN_PMSR);

	chip = this_cpu_read(chip_info);



	/* Check for Pmax Capping */

	pmsr_pmax = (s8)PMSR_MAX(pmsr);

	if (pmsr_pmax != powernv_pstate_info.max) {

	pmsr_pmax_idx = pstate_to_idx(pmsr_pmax);

	if (pmsr_pmax_idx != powernv_pstate_info.max) {

		if (chip->throttled)

			goto next;

		chip->throttled = true;

		if (pmsr_pmax < powernv_pstate_info.nominal) {

			pr_warn_once("CPU %d on Chip %u has Pmax reduced below nominal frequency (%d < %d)\n",

		if (pmsr_pmax_idx > powernv_pstate_info.nominal) {

			pr_warn_once("CPU %d on Chip %u has Pmax(%d) reduced below nominal frequency(%d)\n",

				     cpu, chip->id, pmsr_pmax,

				     powernv_pstate_info.nominal);

				     idx_to_pstate(powernv_pstate_info.nominal));

			chip->throttle_sub_turbo++;

		} else {

			chip->throttle_turbo++;
@@ -485,33 +511,34 @@ next: 
/**

 * calc_global_pstate - Calculate global pstate

 * @elapsed_time:		Elapsed time in milliseconds

 * @local_pstate:	New local pstate

 * @highest_lpstate:	pstate from which its ramping down

 * @local_pstate_idx:		New local pstate

 * @highest_lpstate_idx:	pstate from which its ramping down

 *

 * Finds the appropriate global pstate based on the pstate from which its

 * ramping down and the time elapsed in ramping down. It follows a quadratic

 * equation which ensures that it reaches ramping down to pmin in 5sec.

 */

static inline int calc_global_pstate(unsigned int elapsed_time,

				     int highest_lpstate, int local_pstate)

				     int highest_lpstate_idx,

				     int local_pstate_idx)

{

	int pstate_diff;

	int index_diff;



	/*

	 * Using ramp_down_percent we get the percentage of rampdown

	 * that we are expecting to be dropping. Difference between

	 * highest_lpstate and powernv_pstate_info.min will give a absolute

	 * highest_lpstate_idx and powernv_pstate_info.min will give a absolute

	 * number of how many pstates we will drop eventually by the end of

	 * 5 seconds, then just scale it get the number pstates to be dropped.

	 */

	pstate_diff =  ((int)ramp_down_percent(elapsed_time) *

			(highest_lpstate - powernv_pstate_info.min)) / 100;

	index_diff =  ((int)ramp_down_percent(elapsed_time) *

			(powernv_pstate_info.min - highest_lpstate_idx)) / 100;



	/* Ensure that global pstate is >= to local pstate */

	if (highest_lpstate - pstate_diff < local_pstate)

		return local_pstate;

	if (highest_lpstate_idx + index_diff >= local_pstate_idx)

		return local_pstate_idx;

	else

		return highest_lpstate - pstate_diff;

		return highest_lpstate_idx + index_diff;

}



static inline void  queue_gpstate_timer(struct global_pstate_info *gpstates)
@@ -547,7 +574,7 @@ void gpstate_timer_handler(unsigned long data) 
{

	struct cpufreq_policy *policy = (struct cpufreq_policy *)data;

	struct global_pstate_info *gpstates = policy->driver_data;

	int gpstate_id;

	int gpstate_idx;

	unsigned int time_diff = jiffies_to_msecs(jiffies)

					- gpstates->last_sampled_time;

	struct powernv_smp_call_data freq_data;
@@ -557,16 +584,16 @@ void gpstate_timer_handler(unsigned long data) 


	gpstates->last_sampled_time += time_diff;

	gpstates->elapsed_time += time_diff;

	freq_data.pstate_id = gpstates->last_lpstate;

	freq_data.pstate_id = idx_to_pstate(gpstates->last_lpstate_idx);



	if ((gpstates->last_gpstate == freq_data.pstate_id) ||

	if ((gpstates->last_gpstate_idx == gpstates->last_lpstate_idx) ||

	    (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME)) {

		gpstate_id = freq_data.pstate_id;

		gpstate_idx = pstate_to_idx(freq_data.pstate_id);

		reset_gpstates(policy);

		gpstates->highest_lpstate = freq_data.pstate_id;

		gpstates->highest_lpstate_idx = gpstate_idx;

	} else {

		gpstate_id = calc_global_pstate(gpstates->elapsed_time,

						gpstates->highest_lpstate,

		gpstate_idx = calc_global_pstate(gpstates->elapsed_time,

						 gpstates->highest_lpstate_idx,

						 freq_data.pstate_id);

	}
@@ -574,12 +601,12 @@ void gpstate_timer_handler(unsigned long data) 
	 * If local pstate is equal to global pstate, rampdown is over

	 * So timer is not required to be queued.

	 */

	if (gpstate_id != freq_data.pstate_id)

	if (gpstate_idx != gpstates->last_lpstate_idx)

		queue_gpstate_timer(gpstates);



	freq_data.gpstate_id = gpstate_id;

	gpstates->last_gpstate = freq_data.gpstate_id;

	gpstates->last_lpstate = freq_data.pstate_id;

	freq_data.gpstate_id = idx_to_pstate(gpstate_idx);

	gpstates->last_gpstate_idx = pstate_to_idx(freq_data.gpstate_id);

	gpstates->last_lpstate_idx = pstate_to_idx(freq_data.pstate_id);



	spin_unlock(&gpstates->gpstate_lock);
@@ -596,7 +623,7 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy, 
					unsigned int new_index)

{

	struct powernv_smp_call_data freq_data;

	unsigned int cur_msec, gpstate_id;

	unsigned int cur_msec, gpstate_idx;

	struct global_pstate_info *gpstates = policy->driver_data;



	if (unlikely(rebooting) && new_index != get_nominal_index())
@@ -608,15 +635,15 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy, 
	cur_msec = jiffies_to_msecs(get_jiffies_64());



	spin_lock(&gpstates->gpstate_lock);

	freq_data.pstate_id = powernv_freqs[new_index].driver_data;

	freq_data.pstate_id = idx_to_pstate(new_index);



	if (!gpstates->last_sampled_time) {

		gpstate_id = freq_data.pstate_id;

		gpstates->highest_lpstate = freq_data.pstate_id;

		gpstate_idx = new_index;

		gpstates->highest_lpstate_idx = new_index;

		goto gpstates_done;

	}



	if (gpstates->last_gpstate > freq_data.pstate_id) {

	if (gpstates->last_gpstate_idx < new_index) {

		gpstates->elapsed_time += cur_msec -

						 gpstates->last_sampled_time;
@@ -627,34 +654,34 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy, 
		 */

		if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {

			reset_gpstates(policy);

			gpstates->highest_lpstate = freq_data.pstate_id;

			gpstate_id = freq_data.pstate_id;

			gpstates->highest_lpstate_idx = new_index;

			gpstate_idx = new_index;

		} else {

		/* Elaspsed_time is less than 5 seconds, continue to rampdown */

			gpstate_id = calc_global_pstate(gpstates->elapsed_time,

							gpstates->highest_lpstate,

							freq_data.pstate_id);

			gpstate_idx = calc_global_pstate(gpstates->elapsed_time,

							 gpstates->highest_lpstate_idx,

							 new_index);

		}

	} else {

		reset_gpstates(policy);

		gpstates->highest_lpstate = freq_data.pstate_id;

		gpstate_id = freq_data.pstate_id;

		gpstates->highest_lpstate_idx = new_index;

		gpstate_idx = new_index;

	}



	/*

	 * If local pstate is equal to global pstate, rampdown is over

	 * So timer is not required to be queued.

	 */

	if (gpstate_id != freq_data.pstate_id)

	if (gpstate_idx != new_index)

		queue_gpstate_timer(gpstates);

	else

		del_timer_sync(&gpstates->timer);



gpstates_done:

	freq_data.gpstate_id = gpstate_id;

	freq_data.gpstate_id = idx_to_pstate(gpstate_idx);

	gpstates->last_sampled_time = cur_msec;

	gpstates->last_gpstate = freq_data.gpstate_id;

	gpstates->last_lpstate = freq_data.pstate_id;

	gpstates->last_gpstate_idx = gpstate_idx;

	gpstates->last_lpstate_idx = new_index;



	spin_unlock(&gpstates->gpstate_lock);
@@ -846,8 +873,8 @@ static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy) 
	struct powernv_smp_call_data freq_data;

	struct global_pstate_info *gpstates = policy->driver_data;



	freq_data.pstate_id = powernv_pstate_info.min;

	freq_data.gpstate_id = powernv_pstate_info.min;

	freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);

	freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);

	smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);

	del_timer_sync(&gpstates->timer);

}

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