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authorViresh Kumar <viresh.kumar@linaro.org>2013-12-03 09:50:46 +0400
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-01-06 17:17:25 +0400
commitd3916691c90dfc9f08328d5cef8181e9ea508c55 (patch)
treee32b3422823ef3a64a42c1c72785a169fff20a9c /drivers/cpufreq/freq_table.c
parentae6b427132ba39d023e332e7d920e9931ff05313 (diff)
downloadlinux-d3916691c90dfc9f08328d5cef8181e9ea508c55.tar.xz
cpufreq: Make sure CPU is running on a freq from freq-table
Sometimes boot loaders set CPU frequency to a value outside of frequency table present with cpufreq core. In such cases CPU might be unstable if it has to run on that frequency for long duration of time and so its better to set it to a frequency which is specified in freq-table. This also makes cpufreq stats inconsistent as cpufreq-stats would fail to register because current frequency of CPU isn't found in freq-table. Because we don't want this change to affect boot process badly, we go for the next freq which is >= policy->cur ('cur' must be set by now, otherwise we will end up setting freq to lowest of the table as 'cur' is initialized to zero). In case current frequency doesn't match any frequency from freq-table, we throw warnings to user, so that user can get this fixed in their bootloaders or freq-tables. Reported-by: Carlos Hernandez <ceh@ti.com> Reported-and-tested-by: Nishanth Menon <nm@ti.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/freq_table.c')
-rw-r--r--drivers/cpufreq/freq_table.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index 3458d27f63b4..a8ac0427fbfe 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -178,7 +178,29 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
+int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
+ unsigned int freq)
+{
+ struct cpufreq_frequency_table *table;
+ int i;
+
+ table = cpufreq_frequency_get_table(policy->cpu);
+ if (unlikely(!table)) {
+ pr_debug("%s: Unable to find frequency table\n", __func__);
+ return -ENOENT;
+ }
+
+ for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+ if (table[i].frequency == freq)
+ return i;
+ }
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_index);
+
static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
+
/**
* show_available_freqs - show available frequencies for the specified CPU
*/