Most of the drivers do following in their ->target_index() routines:
struct cpufreq_freqs freqs;
freqs.old = old freq...
freqs.new = new freq...
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
/* Change rate here */
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
This is replicated over all cpufreq drivers today and there doesn't exists a
good enough reason why this shouldn't be moved to cpufreq core instead.
There are few special cases though, like exynos5440, which doesn't do everything
on the call to ->target_index() routine and call some kind of bottom halves for
doing this work, work/tasklet/etc..
They may continue doing notification from their own code and so this patch
introduces another flag: CPUFREQ_NO_NOTIFICATION, which will be set by such
drivers.
Cc: Andrew Lunn <andrew@xxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@xxxxxxxxx>
Cc: Eric Miao <eric.y.miao@xxxxxxxxx>
Cc: Hans-Christian Egtvedt <egtvedt@xxxxxxxxxxxx>
Cc: Jesper Nilsson <jesper.nilsson@xxxxxxxx>
Cc: John Crispin <blogic@xxxxxxxxxxx>
Cc: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: linux-cris-kernel@xxxxxxxx
Cc: Mikael Starvik <starvik@xxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Cc: Sekhar Nori <nsekhar@xxxxxx>
Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
Cc: sparclinux@xxxxxxxxxxxxxxx
Cc: spear-devel@xxxxxxxxxxx
Cc: Stephen Warren <swarren@xxxxxxxxxx>
Cc: Steven Miao <realmz6@xxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/cpufreq/cpufreq.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/cpufreq.h | 6 ++++++
2 files changed, 40 insertions(+)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index a7a1d3e..2782949 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1673,6 +1673,9 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
retval = cpufreq_driver->target(policy, target_freq, relation);
else if (cpufreq_driver->target_index) {
struct cpufreq_frequency_table *freq_table;
+ struct cpufreq_freqs freqs;
+ unsigned long flags;
+ bool notify;
int index;
freq_table = cpufreq_frequency_get_table(policy->cpu);
@@ -1691,7 +1694,38 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
if (freq_table[index].frequency == policy->cur)
return 0;
+ read_lock_irqsave(&cpufreq_driver_lock, flags);
+ notify = !(cpufreq_driver->flags | CPUFREQ_NO_NOTIFICATION);
+ read_unlock_irqrestore(&cpufreq_driver_lock, flags);
+
+ if (notify) {
+ freqs.old = policy->cur;
+ freqs.new = freq_table[index].frequency;
+
+ pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
+ __func__, policy->cpu, freqs.old,
+ freqs.new);
+
+ cpufreq_notify_transition(policy, &freqs,
+ CPUFREQ_PRECHANGE);
+ }
+
retval = cpufreq_driver->target_index(policy, index);
+ if (retval)
+ pr_err("%s: Failed to change cpu frequency: %d\n",
+ __func__, retval);
+
+ if (notify) {
+ /*
+ * Notify with old freq in case we failed to change
+ * frequency
+ */
+ if (retval)
+ freqs.new = freqs.old;
+
+ cpufreq_notify_transition(policy, &freqs,
+ CPUFREQ_POSTCHANGE);
+ }
}
return retval;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index ff9c8df..62ce478 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -221,6 +221,12 @@ struct cpufreq_driver {
* frequency transitions */
#define CPUFREQ_PM_NO_WARN 0x04 /* don't warn on suspend/resume speed
* mismatches */
+/*
+ * Driver will call cpufreq_notify_transition() in its target_index() routine
+ * and so cpufreq core must not call it. Only useful for drivers that implement
+ * target_index(), unused otherwise.
+ */
+#define CPUFREQ_NO_NOTIFICATION 0x08
int cpufreq_register_driver(struct cpufreq_driver *driver_data);
int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
--
1.7.12.rc2.18.g61b472e
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