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authorRichard Zhao <richard.zhao@linaro.org>2012-09-05 01:08:59 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2012-09-09 22:06:33 +0200
commitec971ea5f2426a0bf9d5cca9a103743918c12978 (patch)
tree58594e18af78718548dea595c26e1a67d964a29e /arch/arm/kernel/smp.c
parente1f0b8e9b04a262834ed111e605e5d215685dfab (diff)
downloadvexpress-lsk-ec971ea5f2426a0bf9d5cca9a103743918c12978.tar.gz
ARM: add cpufreq transiton notifier to adjust loops_per_jiffy for smp
If CONFIG_SMP, cpufreq skips loops_per_jiffy update, because different arch has different per-cpu loops_per_jiffy definition. Signed-off-by: Richard Zhao <richard.zhao@linaro.org> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'arch/arm/kernel/smp.c')
-rw-r--r--arch/arm/kernel/smp.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index ebd8ad274d7..8e03567c958 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -25,6 +25,7 @@
#include <linux/percpu.h>
#include <linux/clockchips.h>
#include <linux/completion.h>
+#include <linux/cpufreq.h>
#include <linux/atomic.h>
#include <asm/cacheflush.h>
@@ -584,3 +585,56 @@ int setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
}
+
+#ifdef CONFIG_CPU_FREQ
+
+static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
+static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
+static unsigned long global_l_p_j_ref;
+static unsigned long global_l_p_j_ref_freq;
+
+static int cpufreq_callback(struct notifier_block *nb,
+ unsigned long val, void *data)
+{
+ struct cpufreq_freqs *freq = data;
+ int cpu = freq->cpu;
+
+ if (freq->flags & CPUFREQ_CONST_LOOPS)
+ return NOTIFY_OK;
+
+ if (!per_cpu(l_p_j_ref, cpu)) {
+ per_cpu(l_p_j_ref, cpu) =
+ per_cpu(cpu_data, cpu).loops_per_jiffy;
+ per_cpu(l_p_j_ref_freq, cpu) = freq->old;
+ if (!global_l_p_j_ref) {
+ global_l_p_j_ref = loops_per_jiffy;
+ global_l_p_j_ref_freq = freq->old;
+ }
+ }
+
+ if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
+ (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
+ (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
+ loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
+ global_l_p_j_ref_freq,
+ freq->new);
+ per_cpu(cpu_data, cpu).loops_per_jiffy =
+ cpufreq_scale(per_cpu(l_p_j_ref, cpu),
+ per_cpu(l_p_j_ref_freq, cpu),
+ freq->new);
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block cpufreq_notifier = {
+ .notifier_call = cpufreq_callback,
+};
+
+static int __init register_cpufreq_notifier(void)
+{
+ return cpufreq_register_notifier(&cpufreq_notifier,
+ CPUFREQ_TRANSITION_NOTIFIER);
+}
+core_initcall(register_cpufreq_notifier);
+
+#endif