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: Akshay Adiga <akshay.ad...@linux.vnet.ibm.com>
Reviewed-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com>
---
Changes from v1:
- changed macro names from get_pstate()/ get_index() to
idx_to_pstate()/ pstate_to_idx()
- Renamed variables that store index instead of pstate_id to *_idx
- Retained previous printk's
v1 : http://marc.info/?l=linux-pm&m=146677701501225&w=1
drivers/cpufreq/powernv-cpufreq.c | 177 ++++++++++++++++++++++----------------
1 file changed, 102 insertions(+), 75 deletions(-)
diff --git a/drivers/cpufreq/powernv-cpufreq.c
b/drivers/cpufreq/powernv-cpufreq.c
index b29c5c2..72c91d8 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -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++;
@@ -484,34 +510,35 @@ 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
+ * @elapsed_time: Elapsed time in milliseconds
+ * @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;
@@ -557,29 +584,29 @@ 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,
- freq_data.pstate_id);
+ gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
+ gpstates->highest_lpstate_idx,
+ freq_data.pstate_id);
}
/*
* 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);
@@ -847,8 +874,8 @@ 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);
}
