drivers/cpufreq/vexpress-spc-cpufreq.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Versatile Express SPC CPUFreq Interface driver
  *
  * Copyright (C) 2013 - 2019 ARM Ltd.
  * Sudeep Holla <sudeep.holla@arm.com>
  *
  * Copyright (C) 2013 Linaro.
  * Viresh Kumar <viresh.kumar@linaro.org>
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/clk.h>
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/cpumask.h>
 #include <linux/cpu_cooling.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pm_opp.h>
 #include <linux/slab.h>
 #include <linux/topology.h>
 #include <linux/types.h>

 /* Currently we support only two clusters */
 #define A15_CLUSTER	0
 #define A7_CLUSTER	1
 #define MAX_CLUSTERS	2

 #ifdef CONFIG_BL_SWITCHER
 #include <asm/bL_switcher.h>
 static bool bL_switching_enabled;
 #define is_bL_switching_enabled()	bL_switching_enabled
 #define set_switching_enabled(x)	(bL_switching_enabled = (x))
 #else
 #define is_bL_switching_enabled()	false
 #define set_switching_enabled(x)	do { } while (0)
 #define bL_switch_request(...)		do { } while (0)
 #define bL_switcher_put_enabled()	do { } while (0)
 #define bL_switcher_get_enabled()	do { } while (0)
 #endif

 #define ACTUAL_FREQ(cluster, freq)  ((cluster == A7_CLUSTER) ? freq << 1 : freq)
 #define VIRT_FREQ(cluster, freq)    ((cluster == A7_CLUSTER) ? freq >> 1 : freq)

 static struct thermal_cooling_device *cdev[MAX_CLUSTERS];
 static struct clk *clk[MAX_CLUSTERS];
 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
 static atomic_t cluster_usage[MAX_CLUSTERS + 1];

 static unsigned int clk_big_min;	/* (Big) clock frequencies */
 static unsigned int clk_little_max;	/* Maximum clock frequency (Little) */

 static DEFINE_PER_CPU(unsigned int, physical_cluster);
 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);

 static struct mutex cluster_lock[MAX_CLUSTERS];

 static inline int raw_cpu_to_cluster(int cpu)
 {
 	return topology_physical_package_id(cpu);
 }

 static inline int cpu_to_cluster(int cpu)
 {
 	return is_bL_switching_enabled() ?
 		MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
 }

 static unsigned int find_cluster_maxfreq(int cluster)
 {
 	int j;
 	u32 max_freq = 0, cpu_freq;

 	for_each_online_cpu(j) {
 		cpu_freq = per_cpu(cpu_last_req_freq, j);

 		if (cluster == per_cpu(physical_cluster, j) &&
 		    max_freq < cpu_freq)
 			max_freq = cpu_freq;
 	}

 	return max_freq;
 }

 static unsigned int clk_get_cpu_rate(unsigned int cpu)
 {
 	u32 cur_cluster = per_cpu(physical_cluster, cpu);
 	u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;

 	/* For switcher we use virtual A7 clock rates */
 	if (is_bL_switching_enabled())
 		rate = VIRT_FREQ(cur_cluster, rate);

 	return rate;
 }

 static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu)
 {
 	if (is_bL_switching_enabled())
 		return per_cpu(cpu_last_req_freq, cpu);
 	else
 		return clk_get_cpu_rate(cpu);
 }

 static unsigned int
 ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
 {
 	u32 new_rate, prev_rate;
 	int ret;
 	bool bLs = is_bL_switching_enabled();

 	mutex_lock(&cluster_lock[new_cluster]);

 	if (bLs) {
 		prev_rate = per_cpu(cpu_last_req_freq, cpu);
 		per_cpu(cpu_last_req_freq, cpu) = rate;
 		per_cpu(physical_cluster, cpu) = new_cluster;

 		new_rate = find_cluster_maxfreq(new_cluster);
 		new_rate = ACTUAL_FREQ(new_cluster, new_rate);
 	} else {
 		new_rate = rate;
 	}

 	ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
 	if (!ret) {
 		/*
 		 * FIXME: clk_set_rate hasn't returned an error here however it
 		 * may be that clk_change_rate failed due to hardware or
 		 * firmware issues and wasn't able to report that due to the
 		 * current design of the clk core layer. To work around this
 		 * problem we will read back the clock rate and check it is
 		 * correct. This needs to be removed once clk core is fixed.
 		 */
 		if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
 			ret = -EIO;
 	}

 	if (WARN_ON(ret)) {
 		if (bLs) {
 			per_cpu(cpu_last_req_freq, cpu) = prev_rate;
 			per_cpu(physical_cluster, cpu) = old_cluster;
 		}

 		mutex_unlock(&cluster_lock[new_cluster]);

 		return ret;
 	}

 	mutex_unlock(&cluster_lock[new_cluster]);

 	/* Recalc freq for old cluster when switching clusters */
 	if (old_cluster != new_cluster) {
 		/* Switch cluster */
 		bL_switch_request(cpu, new_cluster);

 		mutex_lock(&cluster_lock[old_cluster]);

 		/* Set freq of old cluster if there are cpus left on it */
 		new_rate = find_cluster_maxfreq(old_cluster);
 		new_rate = ACTUAL_FREQ(old_cluster, new_rate);

 		if (new_rate &&
 		    clk_set_rate(clk[old_cluster], new_rate * 1000)) {
 			pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
 			       __func__, ret, old_cluster);
 		}
 		mutex_unlock(&cluster_lock[old_cluster]);
 	}

 	return 0;
 }

 /* Set clock frequency */
 static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy,
 				     unsigned int index)
 {
 	u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
 	unsigned int freqs_new;

 	cur_cluster = cpu_to_cluster(cpu);
 	new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);

 	freqs_new = freq_table[cur_cluster][index].frequency;

 	if (is_bL_switching_enabled()) {
 		if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min)
 			new_cluster = A7_CLUSTER;
 		else if (actual_cluster == A7_CLUSTER &&
 			 freqs_new > clk_little_max)
 			new_cluster = A15_CLUSTER;
 	}

 	return ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,
 				       freqs_new);
 }

 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
 {
 	int count;

 	for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
 		;

 	return count;
 }

 /* get the minimum frequency in the cpufreq_frequency_table */
 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
 {
 	struct cpufreq_frequency_table *pos;
 	u32 min_freq = ~0;

 	cpufreq_for_each_entry(pos, table)
 		if (pos->frequency < min_freq)
 			min_freq = pos->frequency;
 	return min_freq;
 }

 /* get the maximum frequency in the cpufreq_frequency_table */
 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
 {
 	struct cpufreq_frequency_table *pos;
 	u32 max_freq = 0;

 	cpufreq_for_each_entry(pos, table)
 		if (pos->frequency > max_freq)
 			max_freq = pos->frequency;
 	return max_freq;
 }

 static bool search_frequency(struct cpufreq_frequency_table *table, int size,
 			     unsigned int freq)
 {
 	int count;

 	for (count = 0; count < size; count++) {
 		if (table[count].frequency == freq)
 			return true;
 	}

 	return false;
 }

 static int merge_cluster_tables(void)
 {
 	int i, j, k = 0, count = 1;
 	struct cpufreq_frequency_table *table;

 	for (i = 0; i < MAX_CLUSTERS; i++)
 		count += get_table_count(freq_table[i]);

 	table = kcalloc(count, sizeof(*table), GFP_KERNEL);
 	if (!table)
 		return -ENOMEM;

 	freq_table[MAX_CLUSTERS] = table;

 	/* Add in reverse order to get freqs in increasing order */
 	for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) {
 		for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
 		     j++) {
 			if (i == A15_CLUSTER &&
 			    search_frequency(table, count, freq_table[i][j].frequency))
 				continue; /* skip duplicates */
 			table[k++].frequency =
 				VIRT_FREQ(i, freq_table[i][j].frequency);
 		}
 	}

 	table[k].driver_data = k;
 	table[k].frequency = CPUFREQ_TABLE_END;

 	return 0;
 }

 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,
 					    const struct cpumask *cpumask)
 {
 	u32 cluster = raw_cpu_to_cluster(cpu_dev->id);

 	if (!freq_table[cluster])
 		return;

 	clk_put(clk[cluster]);
 	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 }

 static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
 					   const struct cpumask *cpumask)
 {
 	u32 cluster = cpu_to_cluster(cpu_dev->id);
 	int i;

 	if (atomic_dec_return(&cluster_usage[cluster]))
 		return;

 	if (cluster < MAX_CLUSTERS)
 		return _put_cluster_clk_and_freq_table(cpu_dev, cpumask);

 	for_each_present_cpu(i) {
 		struct device *cdev = get_cpu_device(i);

 		if (!cdev)
 			return;

 		_put_cluster_clk_and_freq_table(cdev, cpumask);
 	}

 	/* free virtual table */
 	kfree(freq_table[cluster]);
 }

 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
 					   const struct cpumask *cpumask)
 {
 	u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
 	int ret;

 	if (freq_table[cluster])
 		return 0;

 	/*
 	 * platform specific SPC code must initialise the opp table
 	 * so just check if the OPP count is non-zero
 	 */
 	ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;
 	if (ret)
 		goto out;

 	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 	if (ret)
 		goto out;

 	clk[cluster] = clk_get(cpu_dev, NULL);
 	if (!IS_ERR(clk[cluster]))
 		return 0;

 	dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 		__func__, cpu_dev->id, cluster);
 	ret = PTR_ERR(clk[cluster]);
 	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);

 out:
 	dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 		cluster);
 	return ret;
 }

 static int get_cluster_clk_and_freq_table(struct device *cpu_dev,
 					  const struct cpumask *cpumask)
 {
 	u32 cluster = cpu_to_cluster(cpu_dev->id);
 	int i, ret;

 	if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 		return 0;

 	if (cluster < MAX_CLUSTERS) {
 		ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);
 		if (ret)
 			atomic_dec(&cluster_usage[cluster]);
 		return ret;
 	}

 	/*
 	 * Get data for all clusters and fill virtual cluster with a merge of
 	 * both
 	 */
 	for_each_present_cpu(i) {
 		struct device *cdev = get_cpu_device(i);

 		if (!cdev)
 			return -ENODEV;

 		ret = _get_cluster_clk_and_freq_table(cdev, cpumask);
 		if (ret)
 			goto put_clusters;
 	}

 	ret = merge_cluster_tables();
 	if (ret)
 		goto put_clusters;

 	/* Assuming 2 cluster, set clk_big_min and clk_little_max */
 	clk_big_min = get_table_min(freq_table[A15_CLUSTER]);
 	clk_little_max = VIRT_FREQ(A7_CLUSTER,
 				   get_table_max(freq_table[A7_CLUSTER]));

 	return 0;

 put_clusters:
 	for_each_present_cpu(i) {
 		struct device *cdev = get_cpu_device(i);

 		if (!cdev)
 			return -ENODEV;

 		_put_cluster_clk_and_freq_table(cdev, cpumask);
 	}

 	atomic_dec(&cluster_usage[cluster]);

 	return ret;
 }

 /* Per-CPU initialization */
 static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
 {
 	u32 cur_cluster = cpu_to_cluster(policy->cpu);
 	struct device *cpu_dev;
 	int ret;

 	cpu_dev = get_cpu_device(policy->cpu);
 	if (!cpu_dev) {
 		pr_err("%s: failed to get cpu%d device\n", __func__,
 		       policy->cpu);
 		return -ENODEV;
 	}

 	if (cur_cluster < MAX_CLUSTERS) {
 		int cpu;

 		dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);

 		for_each_cpu(cpu, policy->cpus)
 			per_cpu(physical_cluster, cpu) = cur_cluster;
 	} else {
 		/* Assumption: during init, we are always running on A15 */
 		per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
 	}

 	ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
 	if (ret)
 		return ret;

 	policy->freq_table = freq_table[cur_cluster];
 	policy->cpuinfo.transition_latency = 1000000; /* 1 ms */

 	dev_pm_opp_of_register_em(cpu_dev, policy->cpus);

 	if (is_bL_switching_enabled())
 		per_cpu(cpu_last_req_freq, policy->cpu) =
 						clk_get_cpu_rate(policy->cpu);

 	dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 	return 0;
 }

 static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy)
 {
 	struct device *cpu_dev;
 	int cur_cluster = cpu_to_cluster(policy->cpu);

 	if (cur_cluster < MAX_CLUSTERS) {
 		cpufreq_cooling_unregister(cdev[cur_cluster]);
 		cdev[cur_cluster] = NULL;
 	}

 	cpu_dev = get_cpu_device(policy->cpu);
 	if (!cpu_dev) {
 		pr_err("%s: failed to get cpu%d device\n", __func__,
 		       policy->cpu);
 		return -ENODEV;
 	}

 	put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);
 	return 0;
 }

 static void ve_spc_cpufreq_ready(struct cpufreq_policy *policy)
 {
 	int cur_cluster = cpu_to_cluster(policy->cpu);

 	/* Do not register a cpu_cooling device if we are in IKS mode */
 	if (cur_cluster >= MAX_CLUSTERS)
 		return;

 	cdev[cur_cluster] = of_cpufreq_cooling_register(policy);
 }

 static struct cpufreq_driver ve_spc_cpufreq_driver = {
 	.name			= "vexpress-spc",
 	.flags			= CPUFREQ_STICKY |
 					CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
 					CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify			= cpufreq_generic_frequency_table_verify,
 	.target_index		= ve_spc_cpufreq_set_target,
 	.get			= ve_spc_cpufreq_get_rate,
 	.init			= ve_spc_cpufreq_init,
 	.exit			= ve_spc_cpufreq_exit,
 	.ready			= ve_spc_cpufreq_ready,
 	.attr			= cpufreq_generic_attr,
 };

 #ifdef CONFIG_BL_SWITCHER
 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
 					unsigned long action, void *_arg)
 {
 	pr_debug("%s: action: %ld\n", __func__, action);

 	switch (action) {
 	case BL_NOTIFY_PRE_ENABLE:
 	case BL_NOTIFY_PRE_DISABLE:
 		cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 		break;

 	case BL_NOTIFY_POST_ENABLE:
 		set_switching_enabled(true);
 		cpufreq_register_driver(&ve_spc_cpufreq_driver);
 		break;

 	case BL_NOTIFY_POST_DISABLE:
 		set_switching_enabled(false);
 		cpufreq_register_driver(&ve_spc_cpufreq_driver);
 		break;

 	default:
 		return NOTIFY_DONE;
 	}

 	return NOTIFY_OK;
 }

 static struct notifier_block bL_switcher_notifier = {
 	.notifier_call = bL_cpufreq_switcher_notifier,
 };

 static int __bLs_register_notifier(void)
 {
 	return bL_switcher_register_notifier(&bL_switcher_notifier);
 }

 static int __bLs_unregister_notifier(void)
 {
 	return bL_switcher_unregister_notifier(&bL_switcher_notifier);
 }
 #else
 static int __bLs_register_notifier(void) { return 0; }
 static int __bLs_unregister_notifier(void) { return 0; }
 #endif

 static int ve_spc_cpufreq_probe(struct platform_device *pdev)
 {
 	int ret, i;

 	set_switching_enabled(bL_switcher_get_enabled());

 	for (i = 0; i < MAX_CLUSTERS; i++)
 		mutex_init(&cluster_lock[i]);

 	ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);
 	if (ret) {
 		pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 			__func__, ve_spc_cpufreq_driver.name, ret);
 	} else {
 		ret = __bLs_register_notifier();
 		if (ret)
 			cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 		else
 			pr_info("%s: Registered platform driver: %s\n",
 				__func__, ve_spc_cpufreq_driver.name);
 	}

 	bL_switcher_put_enabled();
 	return ret;
 }

 static int ve_spc_cpufreq_remove(struct platform_device *pdev)
 {
 	bL_switcher_get_enabled();
 	__bLs_unregister_notifier();
 	cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
 	bL_switcher_put_enabled();
 	pr_info("%s: Un-registered platform driver: %s\n", __func__,
 		ve_spc_cpufreq_driver.name);
 	return 0;
 }

 static struct platform_driver ve_spc_cpufreq_platdrv = {
 	.driver = {
 		.name	= "vexpress-spc-cpufreq",
 	},
 	.probe		= ve_spc_cpufreq_probe,
 	.remove		= ve_spc_cpufreq_remove,
 };
 module_platform_driver(ve_spc_cpufreq_platdrv);

 MODULE_ALIAS("platform:vexpress-spc-cpufreq");
 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Versatile Express SPC CPUFreq Interface driver
	*
	* Copyright (C) 2013 - 2019 ARM Ltd.
	* Sudeep Holla <sudeep.holla@arm.com>
	*
	* Copyright (C) 2013 Linaro.
	* Viresh Kumar <viresh.kumar@linaro.org>
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/clk.h>
	#include <linux/cpu.h>
	#include <linux/cpufreq.h>
	#include <linux/cpumask.h>
	#include <linux/cpu_cooling.h>
	#include <linux/device.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of_platform.h>
	#include <linux/platform_device.h>
	#include <linux/pm_opp.h>
	#include <linux/slab.h>
	#include <linux/topology.h>
	#include <linux/types.h>

	/* Currently we support only two clusters */
	#define A15_CLUSTER 0
	#define A7_CLUSTER 1
	#define MAX_CLUSTERS 2

	#ifdef CONFIG_BL_SWITCHER
	#include <asm/bL_switcher.h>
	static bool bL_switching_enabled;
	#define is_bL_switching_enabled() bL_switching_enabled
	#define set_switching_enabled(x) (bL_switching_enabled = (x))
	#else
	#define is_bL_switching_enabled() false
	#define set_switching_enabled(x) do { } while (0)
	#define bL_switch_request(...) do { } while (0)
	#define bL_switcher_put_enabled() do { } while (0)
	#define bL_switcher_get_enabled() do { } while (0)
	#endif

	#define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq)
	#define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq)

	static struct thermal_cooling_device *cdev[MAX_CLUSTERS];
	static struct clk *clk[MAX_CLUSTERS];
	static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
	static atomic_t cluster_usage[MAX_CLUSTERS + 1];

	static unsigned int clk_big_min; /* (Big) clock frequencies */
	static unsigned int clk_little_max; /* Maximum clock frequency (Little) */

	static DEFINE_PER_CPU(unsigned int, physical_cluster);
	static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);

	static struct mutex cluster_lock[MAX_CLUSTERS];

	static inline int raw_cpu_to_cluster(int cpu)
	{
	return topology_physical_package_id(cpu);
	}

	static inline int cpu_to_cluster(int cpu)
	{
	return is_bL_switching_enabled() ?
	MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
	}

	static unsigned int find_cluster_maxfreq(int cluster)
	{
	int j;
	u32 max_freq = 0, cpu_freq;

	for_each_online_cpu(j) {
	cpu_freq = per_cpu(cpu_last_req_freq, j);

	if (cluster == per_cpu(physical_cluster, j) &&
	max_freq < cpu_freq)
	max_freq = cpu_freq;
	}

	return max_freq;
	}

	static unsigned int clk_get_cpu_rate(unsigned int cpu)
	{
	u32 cur_cluster = per_cpu(physical_cluster, cpu);
	u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;

	/* For switcher we use virtual A7 clock rates */
	if (is_bL_switching_enabled())
	rate = VIRT_FREQ(cur_cluster, rate);

	return rate;
	}

	static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu)
	{
	if (is_bL_switching_enabled())
	return per_cpu(cpu_last_req_freq, cpu);
	else
	return clk_get_cpu_rate(cpu);
	}

	static unsigned int
	ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
	{
	u32 new_rate, prev_rate;
	int ret;
	bool bLs = is_bL_switching_enabled();

	mutex_lock(&cluster_lock[new_cluster]);

	if (bLs) {
	prev_rate = per_cpu(cpu_last_req_freq, cpu);
	per_cpu(cpu_last_req_freq, cpu) = rate;
	per_cpu(physical_cluster, cpu) = new_cluster;

	new_rate = find_cluster_maxfreq(new_cluster);
	new_rate = ACTUAL_FREQ(new_cluster, new_rate);
	} else {
	new_rate = rate;
	}

	ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
	if (!ret) {
	/*
	* FIXME: clk_set_rate hasn't returned an error here however it
	* may be that clk_change_rate failed due to hardware or
	* firmware issues and wasn't able to report that due to the
	* current design of the clk core layer. To work around this
	* problem we will read back the clock rate and check it is
	* correct. This needs to be removed once clk core is fixed.
	*/
	if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
	ret = -EIO;
	}

	if (WARN_ON(ret)) {
	if (bLs) {
	per_cpu(cpu_last_req_freq, cpu) = prev_rate;
	per_cpu(physical_cluster, cpu) = old_cluster;
	}

	mutex_unlock(&cluster_lock[new_cluster]);

	return ret;
	}

	mutex_unlock(&cluster_lock[new_cluster]);

	/* Recalc freq for old cluster when switching clusters */
	if (old_cluster != new_cluster) {
	/* Switch cluster */
	bL_switch_request(cpu, new_cluster);

	mutex_lock(&cluster_lock[old_cluster]);

	/* Set freq of old cluster if there are cpus left on it */
	new_rate = find_cluster_maxfreq(old_cluster);
	new_rate = ACTUAL_FREQ(old_cluster, new_rate);

	if (new_rate &&
	clk_set_rate(clk[old_cluster], new_rate * 1000)) {
	pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
	__func__, ret, old_cluster);
	}
	mutex_unlock(&cluster_lock[old_cluster]);
	}

	return 0;
	}

	/* Set clock frequency */
	static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy,
	unsigned int index)
	{
	u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
	unsigned int freqs_new;

	cur_cluster = cpu_to_cluster(cpu);
	new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);

	freqs_new = freq_table[cur_cluster][index].frequency;

	if (is_bL_switching_enabled()) {
	if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min)
	new_cluster = A7_CLUSTER;
	else if (actual_cluster == A7_CLUSTER &&
	freqs_new > clk_little_max)
	new_cluster = A15_CLUSTER;
	}

	return ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,
	freqs_new);
	}

	static inline u32 get_table_count(struct cpufreq_frequency_table *table)
	{
	int count;

	for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
	;

	return count;
	}

	/* get the minimum frequency in the cpufreq_frequency_table */
	static inline u32 get_table_min(struct cpufreq_frequency_table *table)
	{
	struct cpufreq_frequency_table *pos;
	u32 min_freq = ~0;

	cpufreq_for_each_entry(pos, table)
	if (pos->frequency < min_freq)
	min_freq = pos->frequency;
	return min_freq;
	}

	/* get the maximum frequency in the cpufreq_frequency_table */
	static inline u32 get_table_max(struct cpufreq_frequency_table *table)
	{
	struct cpufreq_frequency_table *pos;
	u32 max_freq = 0;

	cpufreq_for_each_entry(pos, table)
	if (pos->frequency > max_freq)
	max_freq = pos->frequency;
	return max_freq;
	}

	static bool search_frequency(struct cpufreq_frequency_table *table, int size,
	unsigned int freq)
	{
	int count;

	for (count = 0; count < size; count++) {
	if (table[count].frequency == freq)
	return true;
	}

	return false;
	}

	static int merge_cluster_tables(void)
	{
	int i, j, k = 0, count = 1;
	struct cpufreq_frequency_table *table;

	for (i = 0; i < MAX_CLUSTERS; i++)
	count += get_table_count(freq_table[i]);

	table = kcalloc(count, sizeof(*table), GFP_KERNEL);
	if (!table)
	return -ENOMEM;

	freq_table[MAX_CLUSTERS] = table;

	/* Add in reverse order to get freqs in increasing order */
	for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) {
	for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
	j++) {
	if (i == A15_CLUSTER &&
	search_frequency(table, count, freq_table[i][j].frequency))
	continue; /* skip duplicates */
	table[k++].frequency =
	VIRT_FREQ(i, freq_table[i][j].frequency);
	}
	}

	table[k].driver_data = k;
	table[k].frequency = CPUFREQ_TABLE_END;

	return 0;
	}

	static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,
	const struct cpumask *cpumask)
	{
	u32 cluster = raw_cpu_to_cluster(cpu_dev->id);

	if (!freq_table[cluster])
	return;

	clk_put(clk[cluster]);
	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
	}

	static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
	const struct cpumask *cpumask)
	{
	u32 cluster = cpu_to_cluster(cpu_dev->id);
	int i;

	if (atomic_dec_return(&cluster_usage[cluster]))
	return;

	if (cluster < MAX_CLUSTERS)
	return _put_cluster_clk_and_freq_table(cpu_dev, cpumask);

	for_each_present_cpu(i) {
	struct device *cdev = get_cpu_device(i);

	if (!cdev)
	return;

	_put_cluster_clk_and_freq_table(cdev, cpumask);
	}

	/* free virtual table */
	kfree(freq_table[cluster]);
	}

	static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
	const struct cpumask *cpumask)
	{
	u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
	int ret;

	if (freq_table[cluster])
	return 0;

	/*
	* platform specific SPC code must initialise the opp table
	* so just check if the OPP count is non-zero
	*/
	ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;
	if (ret)
	goto out;

	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
	if (ret)
	goto out;

	clk[cluster] = clk_get(cpu_dev, NULL);
	if (!IS_ERR(clk[cluster]))
	return 0;

	dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
	__func__, cpu_dev->id, cluster);
	ret = PTR_ERR(clk[cluster]);
	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);

	out:
	dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
	cluster);
	return ret;
	}

	static int get_cluster_clk_and_freq_table(struct device *cpu_dev,
	const struct cpumask *cpumask)
	{
	u32 cluster = cpu_to_cluster(cpu_dev->id);
	int i, ret;

	if (atomic_inc_return(&cluster_usage[cluster]) != 1)
	return 0;

	if (cluster < MAX_CLUSTERS) {
	ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);
	if (ret)
	atomic_dec(&cluster_usage[cluster]);
	return ret;
	}

	/*
	* Get data for all clusters and fill virtual cluster with a merge of
	* both
	*/
	for_each_present_cpu(i) {
	struct device *cdev = get_cpu_device(i);

	if (!cdev)
	return -ENODEV;

	ret = _get_cluster_clk_and_freq_table(cdev, cpumask);
	if (ret)
	goto put_clusters;
	}

	ret = merge_cluster_tables();
	if (ret)
	goto put_clusters;

	/* Assuming 2 cluster, set clk_big_min and clk_little_max */
	clk_big_min = get_table_min(freq_table[A15_CLUSTER]);
	clk_little_max = VIRT_FREQ(A7_CLUSTER,
	get_table_max(freq_table[A7_CLUSTER]));

	return 0;

	put_clusters:
	for_each_present_cpu(i) {
	struct device *cdev = get_cpu_device(i);

	if (!cdev)
	return -ENODEV;

	_put_cluster_clk_and_freq_table(cdev, cpumask);
	}

	atomic_dec(&cluster_usage[cluster]);

	return ret;
	}

	/* Per-CPU initialization */
	static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
	{
	u32 cur_cluster = cpu_to_cluster(policy->cpu);
	struct device *cpu_dev;
	int ret;

	cpu_dev = get_cpu_device(policy->cpu);
	if (!cpu_dev) {
	pr_err("%s: failed to get cpu%d device\n", __func__,
	policy->cpu);
	return -ENODEV;
	}

	if (cur_cluster < MAX_CLUSTERS) {
	int cpu;

	dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);

	for_each_cpu(cpu, policy->cpus)
	per_cpu(physical_cluster, cpu) = cur_cluster;
	} else {
	/* Assumption: during init, we are always running on A15 */
	per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
	}

	ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
	if (ret)
	return ret;

	policy->freq_table = freq_table[cur_cluster];
	policy->cpuinfo.transition_latency = 1000000; /* 1 ms */

	dev_pm_opp_of_register_em(cpu_dev, policy->cpus);

	if (is_bL_switching_enabled())
	per_cpu(cpu_last_req_freq, policy->cpu) =
	clk_get_cpu_rate(policy->cpu);

	dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
	return 0;
	}

	static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy)
	{
	struct device *cpu_dev;
	int cur_cluster = cpu_to_cluster(policy->cpu);

	if (cur_cluster < MAX_CLUSTERS) {
	cpufreq_cooling_unregister(cdev[cur_cluster]);
	cdev[cur_cluster] = NULL;
	}

	cpu_dev = get_cpu_device(policy->cpu);
	if (!cpu_dev) {
	pr_err("%s: failed to get cpu%d device\n", __func__,
	policy->cpu);
	return -ENODEV;
	}

	put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);
	return 0;
	}

	static void ve_spc_cpufreq_ready(struct cpufreq_policy *policy)
	{
	int cur_cluster = cpu_to_cluster(policy->cpu);

	/* Do not register a cpu_cooling device if we are in IKS mode */
	if (cur_cluster >= MAX_CLUSTERS)
	return;

	cdev[cur_cluster] = of_cpufreq_cooling_register(policy);
	}

	static struct cpufreq_driver ve_spc_cpufreq_driver = {
	.name = "vexpress-spc",
	.flags = CPUFREQ_STICKY \|
	CPUFREQ_HAVE_GOVERNOR_PER_POLICY \|
	CPUFREQ_NEED_INITIAL_FREQ_CHECK,
	.verify = cpufreq_generic_frequency_table_verify,
	.target_index = ve_spc_cpufreq_set_target,
	.get = ve_spc_cpufreq_get_rate,
	.init = ve_spc_cpufreq_init,
	.exit = ve_spc_cpufreq_exit,
	.ready = ve_spc_cpufreq_ready,
	.attr = cpufreq_generic_attr,
	};

	#ifdef CONFIG_BL_SWITCHER
	static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
	unsigned long action, void *_arg)
	{
	pr_debug("%s: action: %ld\n", __func__, action);

	switch (action) {
	case BL_NOTIFY_PRE_ENABLE:
	case BL_NOTIFY_PRE_DISABLE:
	cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
	break;

	case BL_NOTIFY_POST_ENABLE:
	set_switching_enabled(true);
	cpufreq_register_driver(&ve_spc_cpufreq_driver);
	break;

	case BL_NOTIFY_POST_DISABLE:
	set_switching_enabled(false);
	cpufreq_register_driver(&ve_spc_cpufreq_driver);
	break;

	default:
	return NOTIFY_DONE;
	}

	return NOTIFY_OK;
	}

	static struct notifier_block bL_switcher_notifier = {
	.notifier_call = bL_cpufreq_switcher_notifier,
	};

	static int __bLs_register_notifier(void)
	{
	return bL_switcher_register_notifier(&bL_switcher_notifier);
	}

	static int __bLs_unregister_notifier(void)
	{
	return bL_switcher_unregister_notifier(&bL_switcher_notifier);
	}
	#else
	static int __bLs_register_notifier(void) { return 0; }
	static int __bLs_unregister_notifier(void) { return 0; }
	#endif

	static int ve_spc_cpufreq_probe(struct platform_device *pdev)
	{
	int ret, i;

	set_switching_enabled(bL_switcher_get_enabled());

	for (i = 0; i < MAX_CLUSTERS; i++)
	mutex_init(&cluster_lock[i]);

	ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);
	if (ret) {
	pr_info("%s: Failed registering platform driver: %s, err: %d\n",
	__func__, ve_spc_cpufreq_driver.name, ret);
	} else {
	ret = __bLs_register_notifier();
	if (ret)
	cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
	else
	pr_info("%s: Registered platform driver: %s\n",
	__func__, ve_spc_cpufreq_driver.name);
	}

	bL_switcher_put_enabled();
	return ret;
	}

	static int ve_spc_cpufreq_remove(struct platform_device *pdev)
	{
	bL_switcher_get_enabled();
	__bLs_unregister_notifier();
	cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
	bL_switcher_put_enabled();
	pr_info("%s: Un-registered platform driver: %s\n", __func__,
	ve_spc_cpufreq_driver.name);
	return 0;
	}

	static struct platform_driver ve_spc_cpufreq_platdrv = {
	.driver = {
	.name = "vexpress-spc-cpufreq",
	},
	.probe = ve_spc_cpufreq_probe,
	.remove = ve_spc_cpufreq_remove,
	};
	module_platform_driver(ve_spc_cpufreq_platdrv);

	MODULE_ALIAS("platform:vexpress-spc-cpufreq");
	MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
	MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
	MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
	MODULE_LICENSE("GPL v2");