cpufreq: ARM big LITTLE: Add generic cpufreq driver and its DT glue

big LITTLE is ARM's new Architecture focussing power/performance needs of modern
world. More information about big LITTLE can be found here:

http://www.arm.com/products/processors/technologies/biglittleprocessing.php
http://lwn.net/Articles/481055/

In order to keep cpufreq support for all big LITTLE platforms simple/generic,
this patch tries to add a generic cpufreq driver layer for all big LITTLE
platforms.

The driver is divided into two parts:
- Core driver: Generic and shared across all big LITTLE SoC's
- Glue drivers: Per platform drivers providing ops to the core driver

This patch adds in a generic glue driver which would extract information from
Device Tree.

Future SoC's can either reuse the DT glue or write their own depending on the
need.

Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/cpufreq/arm_big_little.h b/drivers/cpufreq/arm_big_little.h
new file mode 100644
index 000000000000..70f18fc12d4a
--- /dev/null
+++ b/drivers/cpufreq/arm_big_little.h
@@ -0,0 +1,40 @@
+/*
+ * ARM big.LITTLE platform's CPUFreq header file
+ *
+ * Copyright (C) 2013 ARM Ltd.
+ * Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
+ *
+ * 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.
+ */
+#ifndef CPUFREQ_ARM_BIG_LITTLE_H
+#define CPUFREQ_ARM_BIG_LITTLE_H
+
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/types.h>
+
+struct cpufreq_arm_bL_ops {
+	char name[CPUFREQ_NAME_LEN];
+	int (*get_transition_latency)(struct device *cpu_dev);
+
+	/*
+	 * This must set opp table for cpu_dev in a similar way as done by
+	 * of_init_opp_table().
+	 */
+	int (*init_opp_table)(struct device *cpu_dev);
+};
+
+int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops);
+void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops);
+
+#endif /* CPUFREQ_ARM_BIG_LITTLE_H */