cpufreq: move freq change notifications to cpufreq core

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 as flag:
CPUFREQ_ASYNC_NOTIFICATION is already set for them.

All drivers are also modified in this patch to avoid breaking 'git bisect', as
double notification would happen otherwise.

Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Russell King <linux@arm.linux.org.uk>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 37 insertions, 3 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 6c9cbb9ebd1f..02d534da22dd 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1669,6 +1669,8 @@ 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;
+		bool notify;
 		int index;
 
 		freq_table = cpufreq_frequency_get_table(policy->cpu);
@@ -1684,10 +1686,42 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
 			goto out;
 		}
 
-		if (freq_table[index].frequency == policy->cur)
+		if (freq_table[index].frequency == policy->cur) {
 			retval = 0;
-		else
-			retval = cpufreq_driver->target_index(policy, index);
+			goto out;
+		}
+
+		notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
+
+		if (notify) {
+			freqs.old = policy->cur;
+			freqs.new = freq_table[index].frequency;
+			freqs.flags = 0;
+
+			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);
+		}
 	}
 
 out: