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-rw-r--r--Documentation/cpu-freq/cpu-drivers.txt29
-rw-r--r--drivers/cpufreq/Kconfig2
-rw-r--r--drivers/cpufreq/Kconfig.arm3
-rw-r--r--drivers/cpufreq/cpufreq-cpu0.c2
-rw-r--r--drivers/cpufreq/cpufreq.c67
-rw-r--r--drivers/cpufreq/cpufreq_governor.c67
-rw-r--r--drivers/cpufreq/cpufreq_governor.h7
-rw-r--r--drivers/cpufreq/intel_pstate.c6
-rw-r--r--drivers/cpufreq/ppc-corenet-cpufreq.c9
-rw-r--r--drivers/cpufreq/tegra-cpufreq.c100
-rw-r--r--include/linux/cpufreq.h25
11 files changed, 256 insertions, 61 deletions
diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt
index b045fe54986a..14f4e6336d88 100644
--- a/Documentation/cpu-freq/cpu-drivers.txt
+++ b/Documentation/cpu-freq/cpu-drivers.txt
@@ -26,6 +26,7 @@ Contents:
1.4 target/target_index or setpolicy?
1.5 target/target_index
1.6 setpolicy
+1.7 get_intermediate and target_intermediate
2. Frequency Table Helpers
@@ -79,6 +80,10 @@ cpufreq_driver.attr - A pointer to a NULL-terminated list of
"struct freq_attr" which allow to
export values to sysfs.
+cpufreq_driver.get_intermediate
+and target_intermediate Used to switch to stable frequency while
+ changing CPU frequency.
+
1.2 Per-CPU Initialization
--------------------------
@@ -151,7 +156,7 @@ Some cpufreq-capable processors switch the frequency between certain
limits on their own. These shall use the ->setpolicy call
-1.4. target/target_index
+1.5. target/target_index
-------------
The target_index call has two arguments: struct cpufreq_policy *policy,
@@ -160,6 +165,9 @@ and unsigned int index (into the exposed frequency table).
The CPUfreq driver must set the new frequency when called here. The
actual frequency must be determined by freq_table[index].frequency.
+It should always restore to earlier frequency (i.e. policy->restore_freq) in
+case of errors, even if we switched to intermediate frequency earlier.
+
Deprecated:
----------
The target call has three arguments: struct cpufreq_policy *policy,
@@ -179,7 +187,7 @@ Here again the frequency table helper might assist you - see section 2
for details.
-1.5 setpolicy
+1.6 setpolicy
---------------
The setpolicy call only takes a struct cpufreq_policy *policy as
@@ -190,6 +198,23 @@ setting when policy->policy is CPUFREQ_POLICY_PERFORMANCE, and a
powersaving-oriented setting when CPUFREQ_POLICY_POWERSAVE. Also check
the reference implementation in drivers/cpufreq/longrun.c
+1.7 get_intermediate and target_intermediate
+--------------------------------------------
+
+Only for drivers with target_index() and CPUFREQ_ASYNC_NOTIFICATION unset.
+
+get_intermediate should return a stable intermediate frequency platform wants to
+switch to, and target_intermediate() should set CPU to to that frequency, before
+jumping to the frequency corresponding to 'index'. Core will take care of
+sending notifications and driver doesn't have to handle them in
+target_intermediate() or target_index().
+
+Drivers can return '0' from get_intermediate() in case they don't wish to switch
+to intermediate frequency for some target frequency. In that case core will
+directly call ->target_index().
+
+NOTE: ->target_index() should restore to policy->restore_freq in case of
+failures as core would send notifications for that.
2. Frequency Table Helpers
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index 1fbe11f2a146..e473d6555f96 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -185,7 +185,7 @@ config CPU_FREQ_GOV_CONSERVATIVE
config GENERIC_CPUFREQ_CPU0
tristate "Generic CPU0 cpufreq driver"
- depends on HAVE_CLK && REGULATOR && OF && THERMAL && CPU_THERMAL
+ depends on HAVE_CLK && OF
select PM_OPP
help
This adds a generic cpufreq driver for CPU0 frequency management.
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 36d20d0fce27..ebac67115009 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -5,8 +5,7 @@
# big LITTLE core layer and glue drivers
config ARM_BIG_LITTLE_CPUFREQ
tristate "Generic ARM big LITTLE CPUfreq driver"
- depends on (BIG_LITTLE && ARM_CPU_TOPOLOGY) || (ARM64 && SMP)
- depends on HAVE_CLK
+ depends on ARM && BIG_LITTLE && ARM_CPU_TOPOLOGY && HAVE_CLK
select PM_OPP
help
This enables the Generic CPUfreq driver for ARM big.LITTLE platforms.
diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
index 09b9129c7bd3..ee1ae303a07c 100644
--- a/drivers/cpufreq/cpufreq-cpu0.c
+++ b/drivers/cpufreq/cpufreq-cpu0.c
@@ -104,7 +104,7 @@ static int cpu0_cpufreq_init(struct cpufreq_policy *policy)
}
static struct cpufreq_driver cpu0_cpufreq_driver = {
- .flags = CPUFREQ_STICKY,
+ .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = cpu0_set_target,
.get = cpufreq_generic_get,
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index ae11dd51f81d..aed2b0cb83dc 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1816,20 +1816,55 @@ EXPORT_SYMBOL(cpufreq_unregister_notifier);
* GOVERNORS *
*********************************************************************/
+/* Must set freqs->new to intermediate frequency */
+static int __target_intermediate(struct cpufreq_policy *policy,
+ struct cpufreq_freqs *freqs, int index)
+{
+ int ret;
+
+ freqs->new = cpufreq_driver->get_intermediate(policy, index);
+
+ /* We don't need to switch to intermediate freq */
+ if (!freqs->new)
+ return 0;
+
+ pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
+ __func__, policy->cpu, freqs->old, freqs->new);
+
+ cpufreq_freq_transition_begin(policy, freqs);
+ ret = cpufreq_driver->target_intermediate(policy, index);
+ cpufreq_freq_transition_end(policy, freqs, ret);
+
+ if (ret)
+ pr_err("%s: Failed to change to intermediate frequency: %d\n",
+ __func__, ret);
+
+ return ret;
+}
+
static int __target_index(struct cpufreq_policy *policy,
struct cpufreq_frequency_table *freq_table, int index)
{
- struct cpufreq_freqs freqs;
+ struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
+ unsigned int intermediate_freq = 0;
int retval = -EINVAL;
bool notify;
notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
-
if (notify) {
- freqs.old = policy->cur;
- freqs.new = freq_table[index].frequency;
- freqs.flags = 0;
+ /* Handle switching to intermediate frequency */
+ if (cpufreq_driver->get_intermediate) {
+ retval = __target_intermediate(policy, &freqs, index);
+ if (retval)
+ return retval;
+
+ intermediate_freq = freqs.new;
+ /* Set old freq to intermediate */
+ if (intermediate_freq)
+ freqs.old = freqs.new;
+ }
+ freqs.new = freq_table[index].frequency;
pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
__func__, policy->cpu, freqs.old, freqs.new);
@@ -1841,9 +1876,23 @@ static int __target_index(struct cpufreq_policy *policy,
pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
retval);
- if (notify)
+ if (notify) {
cpufreq_freq_transition_end(policy, &freqs, retval);
+ /*
+ * Failed after setting to intermediate freq? Driver should have
+ * reverted back to initial frequency and so should we. Check
+ * here for intermediate_freq instead of get_intermediate, in
+ * case we have't switched to intermediate freq at all.
+ */
+ if (unlikely(retval && intermediate_freq)) {
+ freqs.old = intermediate_freq;
+ freqs.new = policy->restore_freq;
+ cpufreq_freq_transition_begin(policy, &freqs);
+ cpufreq_freq_transition_end(policy, &freqs, 0);
+ }
+ }
+
return retval;
}
@@ -1875,6 +1924,9 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
if (target_freq == policy->cur)
return 0;
+ /* Save last value to restore later on errors */
+ policy->restore_freq = policy->cur;
+
if (cpufreq_driver->target)
retval = cpufreq_driver->target(policy, target_freq, relation);
else if (cpufreq_driver->target_index) {
@@ -2361,7 +2413,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
!(driver_data->setpolicy || driver_data->target_index ||
driver_data->target) ||
(driver_data->setpolicy && (driver_data->target_index ||
- driver_data->target)))
+ driver_data->target)) ||
+ (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
return -EINVAL;
pr_debug("trying to register driver %s\n", driver_data->name);
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index e1c6433b16e0..1b44496b2d2b 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -36,14 +36,29 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
struct od_dbs_tuners *od_tuners = dbs_data->tuners;
struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
struct cpufreq_policy *policy;
+ unsigned int sampling_rate;
unsigned int max_load = 0;
unsigned int ignore_nice;
unsigned int j;
- if (dbs_data->cdata->governor == GOV_ONDEMAND)
+ if (dbs_data->cdata->governor == GOV_ONDEMAND) {
+ struct od_cpu_dbs_info_s *od_dbs_info =
+ dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+
+ /*
+ * Sometimes, the ondemand governor uses an additional
+ * multiplier to give long delays. So apply this multiplier to
+ * the 'sampling_rate', so as to keep the wake-up-from-idle
+ * detection logic a bit conservative.
+ */
+ sampling_rate = od_tuners->sampling_rate;
+ sampling_rate *= od_dbs_info->rate_mult;
+
ignore_nice = od_tuners->ignore_nice_load;
- else
+ } else {
+ sampling_rate = cs_tuners->sampling_rate;
ignore_nice = cs_tuners->ignore_nice_load;
+ }
policy = cdbs->cur_policy;
@@ -96,7 +111,46 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
if (unlikely(!wall_time || wall_time < idle_time))
continue;
- load = 100 * (wall_time - idle_time) / wall_time;
+ /*
+ * If the CPU had gone completely idle, and a task just woke up
+ * on this CPU now, it would be unfair to calculate 'load' the
+ * usual way for this elapsed time-window, because it will show
+ * near-zero load, irrespective of how CPU intensive that task
+ * actually is. This is undesirable for latency-sensitive bursty
+ * workloads.
+ *
+ * To avoid this, we reuse the 'load' from the previous
+ * time-window and give this task a chance to start with a
+ * reasonably high CPU frequency. (However, we shouldn't over-do
+ * this copy, lest we get stuck at a high load (high frequency)
+ * for too long, even when the current system load has actually
+ * dropped down. So we perform the copy only once, upon the
+ * first wake-up from idle.)
+ *
+ * Detecting this situation is easy: the governor's deferrable
+ * timer would not have fired during CPU-idle periods. Hence
+ * an unusually large 'wall_time' (as compared to the sampling
+ * rate) indicates this scenario.
+ *
+ * prev_load can be zero in two cases and we must recalculate it
+ * for both cases:
+ * - during long idle intervals
+ * - explicitly set to zero
+ */
+ if (unlikely(wall_time > (2 * sampling_rate) &&
+ j_cdbs->prev_load)) {
+ load = j_cdbs->prev_load;
+
+ /*
+ * Perform a destructive copy, to ensure that we copy
+ * the previous load only once, upon the first wake-up
+ * from idle.
+ */
+ j_cdbs->prev_load = 0;
+ } else {
+ load = 100 * (wall_time - idle_time) / wall_time;
+ j_cdbs->prev_load = load;
+ }
if (load > max_load)
max_load = load;
@@ -318,11 +372,18 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
for_each_cpu(j, policy->cpus) {
struct cpu_dbs_common_info *j_cdbs =
dbs_data->cdata->get_cpu_cdbs(j);
+ unsigned int prev_load;
j_cdbs->cpu = j;
j_cdbs->cur_policy = policy;
j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
&j_cdbs->prev_cpu_wall, io_busy);
+
+ prev_load = (unsigned int)
+ (j_cdbs->prev_cpu_wall - j_cdbs->prev_cpu_idle);
+ j_cdbs->prev_load = 100 * prev_load /
+ (unsigned int) j_cdbs->prev_cpu_wall;
+
if (ignore_nice)
j_cdbs->prev_cpu_nice =
kcpustat_cpu(j).cpustat[CPUTIME_NICE];
diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
index bfb9ae14142c..cc401d147e72 100644
--- a/drivers/cpufreq/cpufreq_governor.h
+++ b/drivers/cpufreq/cpufreq_governor.h
@@ -134,6 +134,13 @@ struct cpu_dbs_common_info {
u64 prev_cpu_idle;
u64 prev_cpu_wall;
u64 prev_cpu_nice;
+ /*
+ * Used to keep track of load in the previous interval. However, when
+ * explicitly set to zero, it is used as a flag to ensure that we copy
+ * the previous load to the current interval only once, upon the first
+ * wake-up from idle.
+ */
+ unsigned int prev_load;
struct cpufreq_policy *cur_policy;
struct delayed_work work;
/*
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index aebd4572eb6d..4e7f492ad583 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -691,14 +691,8 @@ MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);
static int intel_pstate_init_cpu(unsigned int cpunum)
{
-
- const struct x86_cpu_id *id;
struct cpudata *cpu;
- id = x86_match_cpu(intel_pstate_cpu_ids);
- if (!id)
- return -ENODEV;
-
all_cpu_data[cpunum] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
if (!all_cpu_data[cpunum])
return -ENOMEM;
diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c
index 0af618abebaf..3607070797af 100644
--- a/drivers/cpufreq/ppc-corenet-cpufreq.c
+++ b/drivers/cpufreq/ppc-corenet-cpufreq.c
@@ -138,7 +138,7 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
struct cpufreq_frequency_table *table;
struct cpu_data *data;
unsigned int cpu = policy->cpu;
- u64 transition_latency_hz;
+ u64 u64temp;
np = of_get_cpu_node(cpu, NULL);
if (!np)
@@ -206,9 +206,10 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
for_each_cpu(i, per_cpu(cpu_mask, cpu))
per_cpu(cpu_data, i) = data;
- transition_latency_hz = 12ULL * NSEC_PER_SEC;
- policy->cpuinfo.transition_latency =
- do_div(transition_latency_hz, fsl_get_sys_freq());
+ /* Minimum transition latency is 12 platform clocks */
+ u64temp = 12ULL * NSEC_PER_SEC;
+ do_div(u64temp, fsl_get_sys_freq());
+ policy->cpuinfo.transition_latency = u64temp + 1;
of_node_put(np);
diff --git a/drivers/cpufreq/tegra-cpufreq.c b/drivers/cpufreq/tegra-cpufreq.c
index 6e774c6ac20b..8084c7f7e206 100644
--- a/drivers/cpufreq/tegra-cpufreq.c
+++ b/drivers/cpufreq/tegra-cpufreq.c
@@ -45,46 +45,54 @@ static struct clk *cpu_clk;
static struct clk *pll_x_clk;
static struct clk *pll_p_clk;
static struct clk *emc_clk;
+static bool pll_x_prepared;
-static int tegra_cpu_clk_set_rate(unsigned long rate)
+static unsigned int tegra_get_intermediate(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ unsigned int ifreq = clk_get_rate(pll_p_clk) / 1000;
+
+ /*
+ * Don't switch to intermediate freq if:
+ * - we are already at it, i.e. policy->cur == ifreq
+ * - index corresponds to ifreq
+ */
+ if ((freq_table[index].frequency == ifreq) || (policy->cur == ifreq))
+ return 0;
+
+ return ifreq;
+}
+
+static int tegra_target_intermediate(struct cpufreq_policy *policy,
+ unsigned int index)
{
int ret;
/*
* Take an extra reference to the main pll so it doesn't turn
- * off when we move the cpu off of it
+ * off when we move the cpu off of it as enabling it again while we
+ * switch to it from tegra_target() would take additional time.
+ *
+ * When target-freq is equal to intermediate freq we don't need to
+ * switch to an intermediate freq and so this routine isn't called.
+ * Also, we wouldn't be using pll_x anymore and must not take extra
+ * reference to it, as it can be disabled now to save some power.
*/
clk_prepare_enable(pll_x_clk);
ret = clk_set_parent(cpu_clk, pll_p_clk);
- if (ret) {
- pr_err("Failed to switch cpu to clock pll_p\n");
- goto out;
- }
-
- if (rate == clk_get_rate(pll_p_clk))
- goto out;
-
- ret = clk_set_rate(pll_x_clk, rate);
- if (ret) {
- pr_err("Failed to change pll_x to %lu\n", rate);
- goto out;
- }
-
- ret = clk_set_parent(cpu_clk, pll_x_clk);
- if (ret) {
- pr_err("Failed to switch cpu to clock pll_x\n");
- goto out;
- }
+ if (ret)
+ clk_disable_unprepare(pll_x_clk);
+ else
+ pll_x_prepared = true;
-out:
- clk_disable_unprepare(pll_x_clk);
return ret;
}
static int tegra_target(struct cpufreq_policy *policy, unsigned int index)
{
unsigned long rate = freq_table[index].frequency;
+ unsigned int ifreq = clk_get_rate(pll_p_clk) / 1000;
int ret = 0;
/*
@@ -98,10 +106,30 @@ static int tegra_target(struct cpufreq_policy *policy, unsigned int index)
else
clk_set_rate(emc_clk, 100000000); /* emc 50Mhz */
- ret = tegra_cpu_clk_set_rate(rate * 1000);
+ /*
+ * target freq == pll_p, don't need to take extra reference to pll_x_clk
+ * as it isn't used anymore.
+ */
+ if (rate == ifreq)
+ return clk_set_parent(cpu_clk, pll_p_clk);
+
+ ret = clk_set_rate(pll_x_clk, rate * 1000);
+ /* Restore to earlier frequency on error, i.e. pll_x */
if (ret)
- pr_err("cpu-tegra: Failed to set cpu frequency to %lu kHz\n",
- rate);
+ pr_err("Failed to change pll_x to %lu\n", rate);
+
+ ret = clk_set_parent(cpu_clk, pll_x_clk);
+ /* This shouldn't fail while changing or restoring */
+ WARN_ON(ret);
+
+ /*
+ * Drop count to pll_x clock only if we switched to intermediate freq
+ * earlier while transitioning to a target frequency.
+ */
+ if (pll_x_prepared) {
+ clk_disable_unprepare(pll_x_clk);
+ pll_x_prepared = false;
+ }
return ret;
}
@@ -137,16 +165,18 @@ static int tegra_cpu_exit(struct cpufreq_policy *policy)
}
static struct cpufreq_driver tegra_cpufreq_driver = {
- .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
- .verify = cpufreq_generic_frequency_table_verify,
- .target_index = tegra_target,
- .get = cpufreq_generic_get,
- .init = tegra_cpu_init,
- .exit = tegra_cpu_exit,
- .name = "tegra",
- .attr = cpufreq_generic_attr,
+ .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .get_intermediate = tegra_get_intermediate,
+ .target_intermediate = tegra_target_intermediate,
+ .target_index = tegra_target,
+ .get = cpufreq_generic_get,
+ .init = tegra_cpu_init,
+ .exit = tegra_cpu_exit,
+ .name = "tegra",
+ .attr = cpufreq_generic_attr,
#ifdef CONFIG_PM
- .suspend = cpufreq_generic_suspend,
+ .suspend = cpufreq_generic_suspend,
#endif
};
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 3f458896d45c..ec4112d257bc 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -75,6 +75,7 @@ struct cpufreq_policy {
unsigned int max; /* in kHz */
unsigned int cur; /* in kHz, only needed if cpufreq
* governors are used */
+ unsigned int restore_freq; /* = policy->cur before transition */
unsigned int suspend_freq; /* freq to set during suspend */
unsigned int policy; /* see above */
@@ -221,11 +222,35 @@ struct cpufreq_driver {
/* define one out of two */
int (*setpolicy) (struct cpufreq_policy *policy);
+
+ /*
+ * On failure, should always restore frequency to policy->restore_freq
+ * (i.e. old freq).
+ */
int (*target) (struct cpufreq_policy *policy, /* Deprecated */
unsigned int target_freq,
unsigned int relation);
int (*target_index) (struct cpufreq_policy *policy,
unsigned int index);
+ /*
+ * Only for drivers with target_index() and CPUFREQ_ASYNC_NOTIFICATION
+ * unset.
+ *
+ * get_intermediate should return a stable intermediate frequency
+ * platform wants to switch to and target_intermediate() should set CPU
+ * to to that frequency, before jumping to the frequency corresponding
+ * to 'index'. Core will take care of sending notifications and driver
+ * doesn't have to handle them in target_intermediate() or
+ * target_index().
+ *
+ * Drivers can return '0' from get_intermediate() in case they don't
+ * wish to switch to intermediate frequency for some target frequency.
+ * In that case core will directly call ->target_index().
+ */
+ unsigned int (*get_intermediate)(struct cpufreq_policy *policy,
+ unsigned int index);
+ int (*target_intermediate)(struct cpufreq_policy *policy,
+ unsigned int index);
/* should be defined, if possible */
unsigned int (*get) (unsigned int cpu);
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-07 00:39:33 +0300