Add the rt linux 4.1.3-rt3 as base

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

diff --git a/kernel/drivers/cpufreq/arm_big_little_dt.c b/kernel/drivers/cpufreq/arm_big_little_dt.c
new file mode 100644 (file)
index 0000000..36d91db
--- /dev/null
+++ b/kernel/drivers/cpufreq/arm_big_little_dt.c
@@ -0,0 +1,117 @@
+/*
+ * Generic big.LITTLE CPUFreq Interface driver
+ *
+ * It provides necessary ops to arm_big_little cpufreq driver and gets
+ * Frequency information from Device Tree. Freq table in DT must be in KHz.
+ *
+ * Copyright (C) 2013 Linaro.
+ * Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * 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.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pm_opp.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include "arm_big_little.h"
+
+/* get cpu node with valid operating-points */
+static struct device_node *get_cpu_node_with_valid_op(int cpu)
+{
+       struct device_node *np = of_cpu_device_node_get(cpu);
+
+       if (!of_get_property(np, "operating-points", NULL)) {
+               of_node_put(np);
+               np = NULL;
+       }
+
+       return np;
+}
+
+static int dt_init_opp_table(struct device *cpu_dev)
+{
+       struct device_node *np;
+       int ret;
+
+       np = of_node_get(cpu_dev->of_node);
+       if (!np) {
+               pr_err("failed to find cpu%d node\n", cpu_dev->id);
+               return -ENOENT;
+       }
+
+       ret = of_init_opp_table(cpu_dev);
+       of_node_put(np);
+
+       return ret;
+}
+
+static int dt_get_transition_latency(struct device *cpu_dev)
+{
+       struct device_node *np;
+       u32 transition_latency = CPUFREQ_ETERNAL;
+
+       np = of_node_get(cpu_dev->of_node);
+       if (!np) {
+               pr_info("Failed to find cpu node. Use CPUFREQ_ETERNAL transition latency\n");
+               return CPUFREQ_ETERNAL;
+       }
+
+       of_property_read_u32(np, "clock-latency", &transition_latency);
+       of_node_put(np);
+
+       pr_debug("%s: clock-latency: %d\n", __func__, transition_latency);
+       return transition_latency;
+}
+
+static struct cpufreq_arm_bL_ops dt_bL_ops = {
+       .name   = "dt-bl",
+       .get_transition_latency = dt_get_transition_latency,
+       .init_opp_table = dt_init_opp_table,
+       .free_opp_table = of_free_opp_table,
+};
+
+static int generic_bL_probe(struct platform_device *pdev)
+{
+       struct device_node *np;
+
+       np = get_cpu_node_with_valid_op(0);
+       if (!np)
+               return -ENODEV;
+
+       of_node_put(np);
+       return bL_cpufreq_register(&dt_bL_ops);
+}
+
+static int generic_bL_remove(struct platform_device *pdev)
+{
+       bL_cpufreq_unregister(&dt_bL_ops);
+       return 0;
+}
+
+static struct platform_driver generic_bL_platdrv = {
+       .driver = {
+               .name   = "arm-bL-cpufreq-dt",
+       },
+       .probe          = generic_bL_probe,
+       .remove         = generic_bL_remove,
+};
+module_platform_driver(generic_bL_platdrv);
+
+MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
+MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT");
+MODULE_LICENSE("GPL v2");