2 files changed, 34 insertions, 0 deletions

diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 8ba0ed0b9ddb..01e366d2b6fb 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -167,6 +167,19 @@ int acpi_processor_ppc_has_changed(struct acpi_processor *pr)
                 return cpufreq_update_policy(pr->id);
 }
 
+int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
+{
+        struct acpi_processor *pr;
+
+        pr = per_cpu(processors, cpu);
+        if (!pr || !pr->performance || !pr->performance->state_count)
+                return -ENODEV;
+        *limit = pr->performance->states[pr->performance_platform_limit].
+                core_frequency * 1000;
+        return 0;
+}
+EXPORT_SYMBOL(acpi_processor_get_bios_limit);
+
 void acpi_processor_ppc_init(void)
 {
         if (!cpufreq_register_notifier
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 5b9b1c8c4950..f20668c09ce0 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -647,6 +647,21 @@ static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
         return policy->governor->show_setspeed(policy, buf);
 }
 
+/**
+ * show_scaling_driver - show the current cpufreq HW/BIOS limitation
+ */
+static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
+{
+        unsigned int limit;
+        int ret;
+        if (cpufreq_driver->bios_limit) {
+                ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
+                if (!ret)
+                        return sprintf(buf, "%u\n", limit);
+        }
+        return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
+}
+
 #define define_one_ro(_name) \
 static struct freq_attr _name = \
 __ATTR(_name, 0444, show_##_name, NULL)
@@ -666,6 +681,7 @@ define_one_ro(cpuinfo_transition_latency);
 define_one_ro(scaling_available_governors);
 define_one_ro(scaling_driver);
 define_one_ro(scaling_cur_freq);
+define_one_ro(bios_limit);
 define_one_ro(related_cpus);
 define_one_ro(affected_cpus);
 define_one_rw(scaling_min_freq);
@@ -905,6 +921,11 @@ static int cpufreq_add_dev_interface(unsigned int cpu,
                 if (ret)
                         goto err_out_kobj_put;
         }
+        if (cpufreq_driver->bios_limit) {
+                ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
+                if (ret)
+                        goto err_out_kobj_put;
+        }
 
         spin_lock_irqsave(&cpufreq_driver_lock, flags);
         for_each_cpu(j, policy->cpus) {