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@lunn.ch Cc: David S. Miller davem@davemloft.net Cc: Dmitry Eremin-Solenikov dbaryshkov@gmail.com Cc: Eric Miao eric.y.miao@gmail.com Cc: Hans-Christian Egtvedt egtvedt@samfundet.no Cc: Jesper Nilsson jesper.nilsson@axis.com Cc: John Crispin blogic@openwrt.org Cc: Kukjin Kim kgene.kim@samsung.com Cc: Linus Walleij linus.walleij@linaro.org Cc: linux-cris-kernel@axis.com Cc: Mikael Starvik starvik@axis.com Cc: Russell King linux@arm.linux.org.uk Cc: Santosh Shilimkar santosh.shilimkar@ti.com Cc: Sekhar Nori nsekhar@ti.com Cc: Shawn Guo shawn.guo@linaro.org Cc: sparclinux@vger.kernel.org Cc: spear-devel@list.st.com Cc: Stephen Warren swarren@nvidia.com Cc: Steven Miao realmz6@gmail.com Cc: Tony Luck tony.luck@intel.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- 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);