Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / cpufreq / cpufreq_opp.c

diff --git a/kernel/drivers/cpufreq/cpufreq_opp.c b/kernel/drivers/cpufreq/cpufreq_opp.c
new file mode 100644 (file)
index 0000000..773bcde
--- /dev/null
+++ b/kernel/drivers/cpufreq/cpufreq_opp.c
@@ -0,0 +1,110 @@
+/*
+ * Generic OPP helper interface for CPUFreq drivers
+ *
+ * Copyright (C) 2009-2014 Texas Instruments Incorporated.
+ *     Nishanth Menon
+ *     Romit Dasgupta
+ *     Kevin Hilman
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/pm_opp.h>
+#include <linux/rcupdate.h>
+#include <linux/slab.h>
+
+/**
+ * dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
+ * @dev:       device for which we do this operation
+ * @table:     Cpufreq table returned back to caller
+ *
+ * Generate a cpufreq table for a provided device- this assumes that the
+ * opp list is already initialized and ready for usage.
+ *
+ * This function allocates required memory for the cpufreq table. It is
+ * expected that the caller does the required maintenance such as freeing
+ * the table as required.
+ *
+ * Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
+ * if no memory available for the operation (table is not populated), returns 0
+ * if successful and table is populated.
+ *
+ * WARNING: It is  important for the callers to ensure refreshing their copy of
+ * the table if any of the mentioned functions have been invoked in the interim.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Since we just use the regular accessor functions to access the internal data
+ * structures, we use RCU read lock inside this function. As a result, users of
+ * this function DONOT need to use explicit locks for invoking.
+ */
+int dev_pm_opp_init_cpufreq_table(struct device *dev,
+                                 struct cpufreq_frequency_table **table)
+{
+       struct dev_pm_opp *opp;
+       struct cpufreq_frequency_table *freq_table = NULL;
+       int i, max_opps, ret = 0;
+       unsigned long rate;
+
+       rcu_read_lock();
+
+       max_opps = dev_pm_opp_get_opp_count(dev);
+       if (max_opps <= 0) {
+               ret = max_opps ? max_opps : -ENODATA;
+               goto out;
+       }
+
+       freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC);
+       if (!freq_table) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       for (i = 0, rate = 0; i < max_opps; i++, rate++) {
+               /* find next rate */
+               opp = dev_pm_opp_find_freq_ceil(dev, &rate);
+               if (IS_ERR(opp)) {
+                       ret = PTR_ERR(opp);
+                       goto out;
+               }
+               freq_table[i].driver_data = i;
+               freq_table[i].frequency = rate / 1000;
+       }
+
+       freq_table[i].driver_data = i;
+       freq_table[i].frequency = CPUFREQ_TABLE_END;
+
+       *table = &freq_table[0];
+
+out:
+       rcu_read_unlock();
+       if (ret)
+               kfree(freq_table);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);
+
+/**
+ * dev_pm_opp_free_cpufreq_table() - free the cpufreq table
+ * @dev:       device for which we do this operation
+ * @table:     table to free
+ *
+ * Free up the table allocated by dev_pm_opp_init_cpufreq_table
+ */
+void dev_pm_opp_free_cpufreq_table(struct device *dev,
+                                  struct cpufreq_frequency_table **table)
+{
+       if (!table)
+               return;
+
+       kfree(*table);
+       *table = NULL;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);