Hi Viresh,
Hi,
On 6 June 2013 12:37, Lukasz Majewski l.majewski@samsung.com wrote:
This commit adds support for software based frequency boosting. Exynos4 SoCs (e.g. 4x12) allow setting of frequency above its normal condition limits. This can be done for some short time.
Overclocking (boost) support came from cpufreq driver (which is platform dependent). Hence the data structure describing it is defined at its file.
To allow support for either SW and HW (Intel) based boosting, the cpufreq core code has been extended to support both solutions.
The main boost switch has been put at /sys/devices/system/cpu/cpufreq/boost.
Log requires some better paragraphs but I am not concerned about it for now.
Signed-off-by: Lukasz Majewski l.majewski@samsung.com Signed-off-by: Myungjoo Ham myungjoo.ham@samsung.com
drivers/cpufreq/cpufreq.c | 156 ++++++++++++++++++++++++++++++++++++++++++ drivers/cpufreq/freq_table.c | 87 ++++++++++++++++++++++- include/linux/cpufreq.h | 35 +++++++++- 3 files changed, 275 insertions(+), 3 deletions(-)
My initial view on this patch is: "It is overly engineered and needs to get simplified"
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index ca74e27..8cf9a92 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -133,6 +133,11 @@ bool have_governor_per_policy(void) return cpufreq_driver->have_governor_per_policy; }
+/**
- Global definition of cpufreq_boost structure
- */
+struct cpufreq_boost *cpufreq_boost;
Probably just a 'static bool' here cpufreq_boost_enabled. Which takes care of selection from sysfs.
The pointer to struct cpufreq_boost is needed for further reference (as it is now done with struct cpufreq_driver pointer - *cpufreq_driver - defined at cpufreq.c file).
static struct cpufreq_governor *__find_governor(const char *str_governor) { @@ -761,6 +805,18 @@ static int cpufreq_add_dev_interface(unsigned int cpu, if (cpufreq_set_drv_attr_files(policy, cpufreq_driver->attr)) goto err_out_kobj_put;
if (cpufreq_driver->boost) {if (sysfs_create_file(cpufreq_global_kobject,&(global_boost.attr)))This will report error for systems where we have two policy structures. As we are creating something already present.
Good point, thanks.
pr_warn("could not register global boostsysfs file\n");
elsepr_debug("registered global boost sysfsfile\n");
Please make all your prints to print function name too:
pr_debug("%s: foo\n", __func__, foo);
OK.
if (cpufreq_set_drv_attr_files(policy,cpufreq_driver->boost->attr))
Why is this required? Why do we want platforms to add some files in sysfs?
There are two kinds of attributes, which are exported by boost:
1. global boost (/sys/devices/system/cpu/cpufreq/boost)
2. attributes describing cpufreq abilities when boost is available (/sys/devices/syste/cpu/cpu0/cpufreq/): - scaling_boost_frequencies - which will show over clocked frequencies - the scaling_available_frequencies will also display boosted frequency (when boost enabled)
Information from 2. is cpufreq_driver dependent. And that information shouldn't been displayed when boost is not available
/*********************************************************************
BOOST *
*********************************************************************/ +int cpufreq_boost_trigger_state(struct cpufreq_policy *policy, int state) +{
struct cpufreq_boost *boost;unsigned long flags;int ret = 0;if (!policy || !policy->boost|| !policy->boost->low_level_boost)
return -ENODEV;boost = policy->boost;write_lock_irqsave(&cpufreq_driver_lock, flags);if (boost->status != state) {policy->boost->status = state;ret = boost->low_level_boost(policy, state);if (ret) {pr_err("BOOST cannot %sable low level code(%d)\n",
state ? "en" : "dis", ret);return ret;}}write_unlock_irqrestore(&cpufreq_driver_lock, flags);pr_debug("cpufreq BOOST %sabled\n", state ? "en" : "dis");return 0;+}
+/**
- cpufreq_boost_notifier - notifier callback for cpufreq policy
change.
- <at> nb: struct notifier_block * with callback info.
- <at> event: value showing cpufreq event for which this
function invoked.
- <at> data: callback-specific data
- */
+static int cpufreq_boost_notifier(struct notifier_block *nb,
unsigned long event, void *data)+{
struct cpufreq_policy *policy = data;if (event == CPUFREQ_INCOMPATIBLE) {if (!policy || !policy->boost)return -ENODEV;if (policy->boost->status == CPUFREQ_BOOST_EN) {pr_info("NOTIFIER BOOST: MAX: %d e:%lu cpu:%d\n",
policy->max, event, policy->cpu);cpufreq_boost_trigger_state(policy, 0);}}return 0;+}
+/* Notifier for cpufreq policy change */ +static struct notifier_block cpufreq_boost_notifier_block = {
.notifier_call = cpufreq_boost_notifier,+};
+int cpufreq_boost_init(struct cpufreq_policy *policy) +{
int ret = 0;if (!policy)return -EINVAL;Heh, policy can't be NULL here.
Extra precautions :-). I will remove it.
if (!cpufreq_driver->boost) {pr_err("Boost mode not supported on this device\n");Wow!! You want to screw everybody else's logs with this message. Its not a crime if you don't have boost mode supported :)
Hmm, I've exaggerated a bit here.... :)
Actually this routine must be called only if cpufreq_driver->boost is valid.
return -ENODEV;}policy->boost = cpufreq_boost = cpufreq_driver->boost;Why are we copying same pointer to policy->boost? Driver is passing pointer to a single memory location, just save it globally.
This needs some explanation.
The sysfs entry presented at [1] doesn't bring any useful information to reuse (like *policy). For this reason the global cpufreq_boost pointer is needed.
However to efficiently manage the boost, it is necessary to keep per policy pointer to the only struct cpufreq_boost instance (defined at cpufreq_driver code).
/* disable boost for newly created policy - as we e.g.change
governor */policy->boost->status = CPUFREQ_BOOST_DIS;Drivers supporting boost may want boost to be enabled by default, maybe without any sysfs calls.
This can be done by setting the struct cpufreq_boost status field to CPUFREQ_BOOST_EN at cpufreq driver code (when boost structure is defined)
/* register policy notifier */ret =cpufreq_register_notifier(&cpufreq_boost_notifier_block,
CPUFREQ_POLICY_NOTIFIER);if (ret) {pr_err("CPUFREQ BOOST notifier not registered.\n");return ret;}/* add policy to policies list headed at structcpufreq_boost */
list_add_tail(&policy->boost_list,&cpufreq_boost->policies); +
return 0;+} +EXPORT_SYMBOL_GPL(cpufreq_boost_init);
Why do we need to maintain a list of boost here? notifiers? complex :(
Notifier is needed to disable boost when policy is changed (for example when we change from ondemand/lab to performance governor).
I wanted to avoid the situation when boost stays enabled across different governors.
The list of in system available policies is defined to allow boost enable/disable for all policies available (by changing for example policy->max field).
If we decide, that we will support only one policy (as it is now at e.g. Exynos), the list is unnecessary here.
+/*********************************************************************
REGISTER / UNREGISTER CPUFREQDRIVER * *********************************************************************/
@@ -1954,6 +2106,10 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver) pr_debug("unregistering driver %s\n", driver->name);
subsys_interface_unregister(&cpufreq_interface);
if (cpufreq_driver->boost)sysfs_remove_file(cpufreq_global_kobject,&(global_boost.attr));
You haven't removed this from policy. Memory leak.
Yes, you are right.
unregister_hotcpu_notifier(&cpufreq_cpu_notifier); write_lock_irqsave(&cpufreq_driver_lock, flags);diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c index d7a7966..0e95524 100644 --- a/drivers/cpufreq/freq_table.c +++ b/drivers/cpufreq/freq_table.c @@ -3,6 +3,8 @@
- Copyright (C) 2002 - 2003 Dominik Brodowski
- Copyright (C) 2013 Lukasz Majewski l.majewski@samsung.com
You shouldn't add it unless you did some major work on this file. You aren't maintaining this file in 2013.
OK, I will remove the entry.
+static int cpufreq_frequency_table_skip_boost(struct cpufreq_policy *policy,
unsigned int index)+{
if (index == CPUFREQ_BOOST)if (!policy->boost ||This shouldn't be true. If index has got CPUFREQ_BOOST, then driver has to support boost.
Correct me if I'm wrong here, but in my understanding the boost shall be only supported when both CPUFREQ_BOOST index is defined in a freq_table and boost.state = CPUFREQ_BOOST_EN is set.
Setting of CPUFREQ_BOOST shouldn't by default allow to use over clocking frequency.
policy->boost->status == CPUFREQ_BOOST_DIS)return 1;return 0;+}
+unsigned int +cpufreq_frequency_table_boost_max(struct cpufreq_frequency_table *freq_table) +{
int index, boost_freq_max;for (index = 0, boost_freq_max = 0;freq_table[index].frequency != CPUFREQ_TABLE_END;index++)
if (freq_table[index].index == CPUFREQ_BOOST) {if (freq_table[index].frequency >boost_freq_max)
boost_freq_max =freq_table[index].frequency;
}return boost_freq_max;+} +EXPORT_SYMBOL_GPL(cpufreq_frequency_table_boost_max);
why do we need this?
To evaluate the maximal boost frequency from the frequency table. It is then used as a delimiter (when LAB cooperates with thermal framework).
/*
- if you use these, you must assure that the frequency table is
valid
- all the time between get_attr and put_attr!
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 037d36a..1294c8c 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -88,6 +88,25 @@ struct cpufreq_real_policy { struct cpufreq_governor *governor; /* see below */ };
+#define CPUFREQ_BOOST_DIS (0) +#define CPUFREQ_BOOST_EN (1)
You don't need these.. Just create variable as bool and 0 & 1 would be fine.
Yes, this seems to be a clearer solution.
+struct cpufreq_policy; +struct cpufreq_boost {
unsigned int max_boost_freq; /* maximum value of* boosted freq */unsigned int max_normal_freq; /* non boost maxfreq */
int status; /* status of boost *//* boost sysfs attributies */struct freq_attr **attr;/* low-level trigger for boost */int (*low_level_boost) (struct cpufreq_policy *policy, intstate); +
struct list_head policies;+};
We don't need it. Just add two more fields to cpufreq_driver:
- have_boost_freqs and low_level_boost (maybe a better name.
What's its use?)
The separate struct cpufreq_boost was created to explicitly separate boost fields from cpufreq_driver structure.
If in your opinion this structure is redundant, I can remove it and extend cpufreq_driver structure.
struct cpufreq_policy { /* CPUs sharing clock, require sw coordination */ cpumask_var_t cpus; /* Online CPUs only */ @@ -113,6 +132,9 @@ struct cpufreq_policy {
struct cpufreq_real_policy user_policy;
struct cpufreq_boost *boost;struct list_head boost_list;We don't need both of these.
*boost pointer is necessary when one wants to enable/disable boost from e.g governor code (which operates mostly on struct cpufreq_policy *policy pointers).
The boost_list is necessary to connect policies in a list.
struct kobject kobj; struct completion kobj_unregister;};
@@ -277,7 +302,6 @@ struct cpufreq_driver { int cpufreq_register_driver(struct cpufreq_driver *driver_data); int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
??
void cpufreq_notify_transition(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs, unsigned int state);
@@ -403,6 +427,9 @@ extern struct cpufreq_governor cpufreq_gov_conservative; #define CPUFREQ_ENTRY_INVALID ~0 #define CPUFREQ_TABLE_END ~1
+/* Define index for boost frequency */ +#define CPUFREQ_BOOST ~2
s/CPUFREQ_BOOST/CPUFREQ_BOOST_FREQ
Ok, will be changed to something more descriptive.
Thanks for thorough review :-)