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Date: Wed, 29 Jul 2015 03:03:44 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM list <linux-pm@...r.kernel.org>,
Viresh Kumar <viresh.kumar@...aro.org>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Russell King - ARM Linux <linux@....linux.org.uk>
Subject: [Update 2x][PATCH 7/7] cpufreq: Separate CPU device registration from CPU online
From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
To separate the CPU online interface from the CPU device
registration, split cpufreq_online() out of cpufreq_add_dev()
and make cpufreq_cpu_callback() call the former, while
cpufreq_add_dev() itself will only be used as the CPU device
addition subsystem interface callback.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Suggested-by: Russell King <linux@....linux.org.uk>
---
cpufreq_online() returns an int and cpufreq_add_dev() propagates that to the
caller in this version.
That said I don't agree with using that to defer the platform device probing
in cpufreq-dt. That's just over the top to me.
---
drivers/cpufreq/cpufreq.c | 96 +++++++++++++++++++++++-----------------------
1 file changed, 50 insertions(+), 46 deletions(-)
Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -1191,36 +1191,15 @@ static void cpufreq_policy_free(struct c
kfree(policy);
}
-/**
- * cpufreq_add_dev - add a CPU device
- *
- * Adds the cpufreq interface for a CPU device.
- *
- * The Oracle says: try running cpufreq registration/unregistration concurrently
- * with with cpu hotplugging and all hell will break loose. Tried to clean this
- * mess up, but more thorough testing is needed. - Mathieu
- */
-static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+static int cpufreq_online(unsigned int cpu)
{
- unsigned int j, cpu = dev->id;
- int ret;
struct cpufreq_policy *policy;
- unsigned long flags;
bool recover_policy;
+ unsigned long flags;
+ unsigned int j;
+ int ret;
- pr_debug("adding CPU %u\n", cpu);
-
- if (cpu_is_offline(cpu)) {
- /*
- * Only possible if we are here from the subsys_interface add
- * callback. A hotplug notifier will follow and we will handle
- * it as CPU online then. For now, just create the sysfs link,
- * unless there is no policy or the link is already present.
- */
- policy = per_cpu(cpufreq_cpu_data, cpu);
- return policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
- ? add_cpu_dev_symlink(policy, cpu) : 0;
- }
+ pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
/* Check if this CPU already has a policy to manage it */
policy = per_cpu(cpufreq_cpu_data, cpu);
@@ -1377,6 +1356,35 @@ out_free_policy:
return ret;
}
+/**
+ * cpufreq_add_dev - the cpufreq interface for a CPU device.
+ * @dev: CPU device.
+ * @sif: Subsystem interface structure pointer (not used)
+ */
+static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+{
+ unsigned cpu = dev->id;
+ int ret;
+
+ dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
+
+ if (cpu_online(cpu)) {
+ ret = cpufreq_online(cpu);
+ } else {
+ /*
+ * A hotplug notifier will follow and we will handle it as CPU
+ * online then. For now, just create the sysfs link, unless
+ * there is no policy or the link is already present.
+ */
+ struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
+
+ ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
+ ? add_cpu_dev_symlink(policy, cpu) : 0;
+ }
+
+ return ret;
+}
+
static void cpufreq_offline_prepare(unsigned int cpu)
{
struct cpufreq_policy *policy;
@@ -2340,27 +2348,23 @@ static int cpufreq_cpu_callback(struct n
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
- struct device *dev;
- dev = get_cpu_device(cpu);
- if (dev) {
- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_ONLINE:
- cpufreq_add_dev(dev, NULL);
- break;
-
- case CPU_DOWN_PREPARE:
- cpufreq_offline_prepare(cpu);
- break;
-
- case CPU_POST_DEAD:
- cpufreq_offline_finish(cpu);
- break;
-
- case CPU_DOWN_FAILED:
- cpufreq_add_dev(dev, NULL);
- break;
- }
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_ONLINE:
+ cpufreq_online(cpu);
+ break;
+
+ case CPU_DOWN_PREPARE:
+ cpufreq_offline_prepare(cpu);
+ break;
+
+ case CPU_POST_DEAD:
+ cpufreq_offline_finish(cpu);
+ break;
+
+ case CPU_DOWN_FAILED:
+ cpufreq_online(cpu);
+ break;
}
return NOTIFY_OK;
}
--
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