Commit 47ac9aa1 authored by Sudeep KarkadaNagesha's avatar Sudeep KarkadaNagesha Committed by Rafael J. Wysocki
Browse files

cpufreq: arm_big_little: add vexpress SPC interface driver 



The TC2(i.e. CA15_A7) Versatile Express has external Cortex M3 based
power controller which is responsible for CPU DVFS and SPC provides
the interface for the same.

This patch adds a tiny interface driver to check if OPPs are
initialised by SPC platform code and register the arm_big_little
cpufreq driver.

Signed-off-by: default avatarSudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 4d910d5b

drivers/cpufreq/Kconfig.arm

+8 −0
Original line number Diff line number Diff line
@@ -224,3 +224,11 @@ config ARM_TEGRA_CPUFREQ 
	default y

	help

	  This adds the CPUFreq driver support for TEGRA SOCs.



config ARM_VEXPRESS_SPC_CPUFREQ

        tristate "Versatile Express SPC based CPUfreq driver"

        select ARM_BIG_LITTLE_CPUFREQ

        depends on ARCH_VEXPRESS_SPC

        help

          This add the CPUfreq driver support for Versatile Express

	  big.LITTLE platforms using SPC for power management.

drivers/cpufreq/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ) += sa1100-cpufreq.o 
obj-$(CONFIG_ARM_SA1110_CPUFREQ)	+= sa1110-cpufreq.o

obj-$(CONFIG_ARM_SPEAR_CPUFREQ)		+= spear-cpufreq.o

obj-$(CONFIG_ARM_TEGRA_CPUFREQ)		+= tegra-cpufreq.o

obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ)	+= vexpress-spc-cpufreq.o



##################################################################################

# PowerPC platform drivers

drivers/cpufreq/vexpress-spc-cpufreq.c

0 → 100644
+70 −0
Original line number Diff line number Diff line 
/*

 * Versatile Express SPC CPUFreq Interface driver

 *

 * It provides necessary ops to arm_big_little cpufreq driver.

 *

 * Copyright (C) 2013 ARM Ltd.

 * Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>

 *

 * 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/module.h>

#include <linux/platform_device.h>

#include <linux/pm_opp.h>

#include <linux/types.h>



#include "arm_big_little.h"



static int ve_spc_init_opp_table(struct device *cpu_dev)

{

	/*

	 * platform specific SPC code must initialise the opp table

	 * so just check if the OPP count is non-zero

	 */

	return dev_pm_opp_get_opp_count(cpu_dev) <= 0;

}



static int ve_spc_get_transition_latency(struct device *cpu_dev)

{

	return 1000000; /* 1 ms */

}



static struct cpufreq_arm_bL_ops ve_spc_cpufreq_ops = {

	.name	= "vexpress-spc",

	.get_transition_latency = ve_spc_get_transition_latency,

	.init_opp_table = ve_spc_init_opp_table,

};



static int ve_spc_cpufreq_probe(struct platform_device *pdev)

{

	return bL_cpufreq_register(&ve_spc_cpufreq_ops);

}



static int ve_spc_cpufreq_remove(struct platform_device *pdev)

{

	bL_cpufreq_unregister(&ve_spc_cpufreq_ops);

	return 0;

}



static struct platform_driver ve_spc_cpufreq_platdrv = {

	.driver = {

		.name	= "vexpress-spc-cpufreq",

		.owner	= THIS_MODULE,

	},

	.probe		= ve_spc_cpufreq_probe,

	.remove		= ve_spc_cpufreq_remove,

};

module_platform_driver(ve_spc_cpufreq_platdrv);



MODULE_LICENSE("GPL");

CRA Git | Maintained and supported by SUSTech CRA and CCSE