[linux-block.git] / drivers / cpufreq / vexpress-spc-cpufreq.c

// 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/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 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 */

	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;

	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 struct cpufreq_driver ve_spc_cpufreq_driver = {
	.name			= "vexpress-spc",
	.flags			= 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,
	.register_em		= cpufreq_register_em_with_opp,
	.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]);

	if (!is_bL_switching_enabled())
		ve_spc_cpufreq_driver.flags |= CPUFREQ_IS_COOLING_DEV;

	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");
Commit	Line	Data
a0f950d3	1	// SPDX-License-Identifier: GPL-2.0
47ac9aa1 SK	2	/*
	3	* Versatile Express SPC CPUFreq Interface driver
	4	*
a0f950d3 SH	5	* Copyright (C) 2013 - 2019 ARM Ltd.
a0f950d3 SH	6	* Sudeep Holla <sudeep.holla@arm.com>
47ac9aa1	7	*
a0f950d3 SH	8	* Copyright (C) 2013 Linaro.
a0f950d3 SH	9	* Viresh Kumar <viresh.kumar@linaro.org>
47ac9aa1 SK	10	*/
	11
	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	13
a0f950d3	14	#include <linux/clk.h>
d9975b0b	15	#include <linux/cpu.h>
47ac9aa1	16	#include <linux/cpufreq.h>
a0f950d3	17	#include <linux/cpumask.h>
a0f950d3	18	#include <linux/device.h>
47ac9aa1	19	#include <linux/module.h>
a0f950d3 SH	20	#include <linux/mutex.h>
a0f950d3 SH	21	#include <linux/of_platform.h>
47ac9aa1 SK	22	#include <linux/platform_device.h>
47ac9aa1 SK	23	#include <linux/pm_opp.h>
a0f950d3 SH	24	#include <linux/slab.h>
a0f950d3 SH	25	#include <linux/topology.h>
47ac9aa1 SK	26	#include <linux/types.h>
47ac9aa1 SK	27
a0f950d3 SH	28	/* Currently we support only two clusters */
	29	#define A15_CLUSTER 0
	30	#define A7_CLUSTER 1
	31	#define MAX_CLUSTERS 2
	32
	33	#ifdef CONFIG_BL_SWITCHER
	34	#include <asm/bL_switcher.h>
	35	static bool bL_switching_enabled;
	36	#define is_bL_switching_enabled() bL_switching_enabled
	37	#define set_switching_enabled(x) (bL_switching_enabled = (x))
	38	#else
	39	#define is_bL_switching_enabled() false
	40	#define set_switching_enabled(x) do { } while (0)
	41	#define bL_switch_request(...) do { } while (0)
	42	#define bL_switcher_put_enabled() do { } while (0)
	43	#define bL_switcher_get_enabled() do { } while (0)
	44	#endif
	45
	46	#define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq)
	47	#define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
	48
a0f950d3 SH	49	static struct clk *clk[MAX_CLUSTERS];
	50	static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
	51	static atomic_t cluster_usage[MAX_CLUSTERS + 1];
	52
	53	static unsigned int clk_big_min; /* (Big) clock frequencies */
	54	static unsigned int clk_little_max; /* Maximum clock frequency (Little) */
	55
	56	static DEFINE_PER_CPU(unsigned int, physical_cluster);
	57	static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
	58
	59	static struct mutex cluster_lock[MAX_CLUSTERS];
	60
	61	static inline int raw_cpu_to_cluster(int cpu)
	62	{
	63	return topology_physical_package_id(cpu);
	64	}
	65
	66	static inline int cpu_to_cluster(int cpu)
	67	{
	68	return is_bL_switching_enabled() ?
	69	MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
	70	}
	71
	72	static unsigned int find_cluster_maxfreq(int cluster)
	73	{
	74	int j;
	75	u32 max_freq = 0, cpu_freq;
	76
	77	for_each_online_cpu(j) {
	78	cpu_freq = per_cpu(cpu_last_req_freq, j);
	79
e318d2c8 SH	80	if (cluster == per_cpu(physical_cluster, j) &&
e318d2c8 SH	81	max_freq < cpu_freq)
a0f950d3 SH	82	max_freq = cpu_freq;
	83	}
	84
a0f950d3 SH	85	return max_freq;
	86	}
	87
	88	static unsigned int clk_get_cpu_rate(unsigned int cpu)
	89	{
	90	u32 cur_cluster = per_cpu(physical_cluster, cpu);
	91	u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
	92
	93	/* For switcher we use virtual A7 clock rates */
	94	if (is_bL_switching_enabled())
	95	rate = VIRT_FREQ(cur_cluster, rate);
	96
a0f950d3 SH	97	return rate;
	98	}
	99
1f1b4650	100	static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu)
a0f950d3	101	{
09402d57	102	if (is_bL_switching_enabled())
a0f950d3	103	return per_cpu(cpu_last_req_freq, cpu);
09402d57	104	else
a0f950d3	105	return clk_get_cpu_rate(cpu);
a0f950d3 SH	106	}
	107
	108	static unsigned int
1f1b4650	109	ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
a0f950d3 SH	110	{
	111	u32 new_rate, prev_rate;
	112	int ret;
	113	bool bLs = is_bL_switching_enabled();
	114
	115	mutex_lock(&cluster_lock[new_cluster]);
	116
	117	if (bLs) {
	118	prev_rate = per_cpu(cpu_last_req_freq, cpu);
	119	per_cpu(cpu_last_req_freq, cpu) = rate;
	120	per_cpu(physical_cluster, cpu) = new_cluster;
	121
	122	new_rate = find_cluster_maxfreq(new_cluster);
	123	new_rate = ACTUAL_FREQ(new_cluster, new_rate);
	124	} else {
	125	new_rate = rate;
	126	}
	127
a0f950d3 SH	128	ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
	129	if (!ret) {
	130	/*
	131	* FIXME: clk_set_rate hasn't returned an error here however it
	132	* may be that clk_change_rate failed due to hardware or
	133	* firmware issues and wasn't able to report that due to the
	134	* current design of the clk core layer. To work around this
	135	* problem we will read back the clock rate and check it is
	136	* correct. This needs to be removed once clk core is fixed.
	137	*/
	138	if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
	139	ret = -EIO;
	140	}
	141
	142	if (WARN_ON(ret)) {
a0f950d3 SH	143	if (bLs) {
	144	per_cpu(cpu_last_req_freq, cpu) = prev_rate;
	145	per_cpu(physical_cluster, cpu) = old_cluster;
	146	}
	147
	148	mutex_unlock(&cluster_lock[new_cluster]);
	149
	150	return ret;
	151	}
	152
	153	mutex_unlock(&cluster_lock[new_cluster]);
	154
	155	/* Recalc freq for old cluster when switching clusters */
	156	if (old_cluster != new_cluster) {
a0f950d3 SH	157	/* Switch cluster */
	158	bL_switch_request(cpu, new_cluster);
	159
	160	mutex_lock(&cluster_lock[old_cluster]);
	161
	162	/* Set freq of old cluster if there are cpus left on it */
	163	new_rate = find_cluster_maxfreq(old_cluster);
	164	new_rate = ACTUAL_FREQ(old_cluster, new_rate);
	165
09402d57 SH	166	if (new_rate &&
	167	clk_set_rate(clk[old_cluster], new_rate * 1000)) {
	168	pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
	169	__func__, ret, old_cluster);
a0f950d3 SH	170	}
	171	mutex_unlock(&cluster_lock[old_cluster]);
	172	}
	173
	174	return 0;
	175	}
	176
	177	/* Set clock frequency */
1f1b4650 SH	178	static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy,
1f1b4650 SH	179	unsigned int index)
a0f950d3 SH	180	{
	181	u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
	182	unsigned int freqs_new;
a0f950d3 SH	183
	184	cur_cluster = cpu_to_cluster(cpu);
	185	new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
	186
	187	freqs_new = freq_table[cur_cluster][index].frequency;
	188
	189	if (is_bL_switching_enabled()) {
e318d2c8	190	if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min)
a0f950d3	191	new_cluster = A7_CLUSTER;
e318d2c8 SH	192	else if (actual_cluster == A7_CLUSTER &&
e318d2c8 SH	193	freqs_new > clk_little_max)
a0f950d3	194	new_cluster = A15_CLUSTER;
a0f950d3 SH	195	}
a0f950d3 SH	196
1a0419b0 IV	197	return ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,
1a0419b0 IV	198	freqs_new);
a0f950d3 SH	199	}
	200
	201	static inline u32 get_table_count(struct cpufreq_frequency_table *table)
	202	{
	203	int count;
	204
	205	for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
	206	;
	207
	208	return count;
	209	}
	210
	211	/* get the minimum frequency in the cpufreq_frequency_table */
	212	static inline u32 get_table_min(struct cpufreq_frequency_table *table)
	213	{
	214	struct cpufreq_frequency_table *pos;
e318d2c8 SH	215	u32 min_freq = ~0;
e318d2c8 SH	216
a0f950d3 SH	217	cpufreq_for_each_entry(pos, table)
	218	if (pos->frequency < min_freq)
	219	min_freq = pos->frequency;
	220	return min_freq;
	221	}
	222
	223	/* get the maximum frequency in the cpufreq_frequency_table */
	224	static inline u32 get_table_max(struct cpufreq_frequency_table *table)
	225	{
	226	struct cpufreq_frequency_table *pos;
e318d2c8 SH	227	u32 max_freq = 0;
e318d2c8 SH	228
a0f950d3 SH	229	cpufreq_for_each_entry(pos, table)
	230	if (pos->frequency > max_freq)
	231	max_freq = pos->frequency;
	232	return max_freq;
	233	}
	234
e32beb06 SH	235	static bool search_frequency(struct cpufreq_frequency_table *table, int size,
	236	unsigned int freq)
	237	{
	238	int count;
	239
	240	for (count = 0; count < size; count++) {
	241	if (table[count].frequency == freq)
	242	return true;
	243	}
	244
	245	return false;
	246	}
	247
a0f950d3 SH	248	static int merge_cluster_tables(void)
	249	{
	250	int i, j, k = 0, count = 1;
	251	struct cpufreq_frequency_table *table;
	252
	253	for (i = 0; i < MAX_CLUSTERS; i++)
	254	count += get_table_count(freq_table[i]);
	255
	256	table = kcalloc(count, sizeof(*table), GFP_KERNEL);
	257	if (!table)
	258	return -ENOMEM;
	259
	260	freq_table[MAX_CLUSTERS] = table;
	261
	262	/* Add in reverse order to get freqs in increasing order */
e32beb06	263	for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) {
a0f950d3	264	for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
e32beb06 SH	265	j++) {
	266	if (i == A15_CLUSTER &&
	267	search_frequency(table, count, freq_table[i][j].frequency))
	268	continue; /* skip duplicates */
	269	table[k++].frequency =
e318d2c8	270	VIRT_FREQ(i, freq_table[i][j].frequency);
a0f950d3 SH	271	}
	272	}
	273
	274	table[k].driver_data = k;
	275	table[k].frequency = CPUFREQ_TABLE_END;
	276
a0f950d3 SH	277	return 0;
	278	}
	279
	280	static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,
	281	const struct cpumask *cpumask)
	282	{
	283	u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
	284
	285	if (!freq_table[cluster])
	286	return;
	287
	288	clk_put(clk[cluster]);
	289	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
a0f950d3 SH	290	}
	291
	292	static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
	293	const struct cpumask *cpumask)
	294	{
	295	u32 cluster = cpu_to_cluster(cpu_dev->id);
	296	int i;
	297
	298	if (atomic_dec_return(&cluster_usage[cluster]))
	299	return;
	300
	301	if (cluster < MAX_CLUSTERS)
	302	return _put_cluster_clk_and_freq_table(cpu_dev, cpumask);
	303
	304	for_each_present_cpu(i) {
	305	struct device *cdev = get_cpu_device(i);
09402d57 SH	306
09402d57 SH	307	if (!cdev)
a0f950d3	308	return;
a0f950d3 SH	309
	310	_put_cluster_clk_and_freq_table(cdev, cpumask);
	311	}
	312
	313	/* free virtual table */
	314	kfree(freq_table[cluster]);
	315	}
	316
	317	static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
	318	const struct cpumask *cpumask)
	319	{
	320	u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
	321	int ret;
	322
	323	if (freq_table[cluster])
	324	return 0;
	325
1f1b4650 SH	326	/*
	327	* platform specific SPC code must initialise the opp table
	328	* so just check if the OPP count is non-zero
	329	*/
	330	ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;
	331	if (ret)
a0f950d3	332	goto out;
a0f950d3 SH	333
a0f950d3 SH	334	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
09402d57	335	if (ret)
1f1b4650	336	goto out;
a0f950d3 SH	337
a0f950d3 SH	338	clk[cluster] = clk_get(cpu_dev, NULL);
09402d57	339	if (!IS_ERR(clk[cluster]))
a0f950d3	340	return 0;
a0f950d3 SH	341
a0f950d3 SH	342	dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
e318d2c8	343	__func__, cpu_dev->id, cluster);
a0f950d3 SH	344	ret = PTR_ERR(clk[cluster]);
	345	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
	346
a0f950d3 SH	347	out:
a0f950d3 SH	348	dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
e318d2c8	349	cluster);
a0f950d3 SH	350	return ret;
	351	}
	352
	353	static int get_cluster_clk_and_freq_table(struct device *cpu_dev,
	354	const struct cpumask *cpumask)
	355	{
	356	u32 cluster = cpu_to_cluster(cpu_dev->id);
	357	int i, ret;
	358
	359	if (atomic_inc_return(&cluster_usage[cluster]) != 1)
	360	return 0;
	361
	362	if (cluster < MAX_CLUSTERS) {
	363	ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);
	364	if (ret)
	365	atomic_dec(&cluster_usage[cluster]);
	366	return ret;
	367	}
	368
	369	/*
	370	* Get data for all clusters and fill virtual cluster with a merge of
	371	* both
	372	*/
	373	for_each_present_cpu(i) {
	374	struct device *cdev = get_cpu_device(i);
09402d57 SH	375
09402d57 SH	376	if (!cdev)
a0f950d3	377	return -ENODEV;
a0f950d3 SH	378
	379	ret = _get_cluster_clk_and_freq_table(cdev, cpumask);
	380	if (ret)
	381	goto put_clusters;
	382	}
	383
	384	ret = merge_cluster_tables();
	385	if (ret)
	386	goto put_clusters;
	387
	388	/* Assuming 2 cluster, set clk_big_min and clk_little_max */
4a6e1352 SH	389	clk_big_min = get_table_min(freq_table[A15_CLUSTER]);
	390	clk_little_max = VIRT_FREQ(A7_CLUSTER,
	391	get_table_max(freq_table[A7_CLUSTER]));
a0f950d3	392
a0f950d3 SH	393	return 0;
	394
	395	put_clusters:
	396	for_each_present_cpu(i) {
	397	struct device *cdev = get_cpu_device(i);
09402d57 SH	398
09402d57 SH	399	if (!cdev)
a0f950d3	400	return -ENODEV;
a0f950d3 SH	401
	402	_put_cluster_clk_and_freq_table(cdev, cpumask);
	403	}
	404
	405	atomic_dec(&cluster_usage[cluster]);
	406
	407	return ret;
	408	}
	409
	410	/* Per-CPU initialization */
1f1b4650	411	static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
a0f950d3 SH	412	{
	413	u32 cur_cluster = cpu_to_cluster(policy->cpu);
	414	struct device *cpu_dev;
	415	int ret;
	416
	417	cpu_dev = get_cpu_device(policy->cpu);
	418	if (!cpu_dev) {
	419	pr_err("%s: failed to get cpu%d device\n", __func__,
e318d2c8	420	policy->cpu);
a0f950d3 SH	421	return -ENODEV;
	422	}
	423
	424	if (cur_cluster < MAX_CLUSTERS) {
	425	int cpu;
	426
c9385887	427	dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);
a0f950d3 SH	428
	429	for_each_cpu(cpu, policy->cpus)
	430	per_cpu(physical_cluster, cpu) = cur_cluster;
	431	} else {
	432	/* Assumption: during init, we are always running on A15 */
	433	per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
	434	}
	435
	436	ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
	437	if (ret)
	438	return ret;
	439
	440	policy->freq_table = freq_table[cur_cluster];
1f1b4650	441	policy->cpuinfo.transition_latency = 1000000; /* 1 ms */
a0f950d3	442
a0f950d3	443	if (is_bL_switching_enabled())
e318d2c8 SH	444	per_cpu(cpu_last_req_freq, policy->cpu) =
e318d2c8 SH	445	clk_get_cpu_rate(policy->cpu);
a0f950d3 SH	446
	447	dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
	448	return 0;
	449	}
	450
1f1b4650	451	static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy)
a0f950d3 SH	452	{
a0f950d3 SH	453	struct device *cpu_dev;
a0f950d3	454
a0f950d3 SH	455	cpu_dev = get_cpu_device(policy->cpu);
	456	if (!cpu_dev) {
	457	pr_err("%s: failed to get cpu%d device\n", __func__,
e318d2c8	458	policy->cpu);
a0f950d3 SH	459	return -ENODEV;
	460	}
	461
	462	put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);
a0f950d3 SH	463	return 0;
	464	}
	465
1f1b4650 SH	466	static struct cpufreq_driver ve_spc_cpufreq_driver = {
1f1b4650 SH	467	.name = "vexpress-spc",
5ae4a4b4	468	.flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY \|
a0f950d3 SH	469	CPUFREQ_NEED_INITIAL_FREQ_CHECK,
a0f950d3 SH	470	.verify = cpufreq_generic_frequency_table_verify,
1f1b4650 SH	471	.target_index = ve_spc_cpufreq_set_target,
	472	.get = ve_spc_cpufreq_get_rate,
	473	.init = ve_spc_cpufreq_init,
	474	.exit = ve_spc_cpufreq_exit,
3fd23111	475	.register_em = cpufreq_register_em_with_opp,
a0f950d3 SH	476	.attr = cpufreq_generic_attr,
	477	};
	478
	479	#ifdef CONFIG_BL_SWITCHER
	480	static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
	481	unsigned long action, void *_arg)
	482	{
	483	pr_debug("%s: action: %ld\n", __func__, action);
	484
	485	switch (action) {
	486	case BL_NOTIFY_PRE_ENABLE:
	487	case BL_NOTIFY_PRE_DISABLE:
1f1b4650	488	cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
a0f950d3 SH	489	break;
	490
	491	case BL_NOTIFY_POST_ENABLE:
	492	set_switching_enabled(true);
1f1b4650	493	cpufreq_register_driver(&ve_spc_cpufreq_driver);
a0f950d3 SH	494	break;
	495
	496	case BL_NOTIFY_POST_DISABLE:
	497	set_switching_enabled(false);
1f1b4650	498	cpufreq_register_driver(&ve_spc_cpufreq_driver);
a0f950d3 SH	499	break;
	500
	501	default:
	502	return NOTIFY_DONE;
	503	}
	504
	505	return NOTIFY_OK;
	506	}
	507
	508	static struct notifier_block bL_switcher_notifier = {
	509	.notifier_call = bL_cpufreq_switcher_notifier,
	510	};
	511
	512	static int __bLs_register_notifier(void)
	513	{
	514	return bL_switcher_register_notifier(&bL_switcher_notifier);
	515	}
	516
	517	static int __bLs_unregister_notifier(void)
	518	{
	519	return bL_switcher_unregister_notifier(&bL_switcher_notifier);
	520	}
	521	#else
	522	static int __bLs_register_notifier(void) { return 0; }
	523	static int __bLs_unregister_notifier(void) { return 0; }
	524	#endif
	525
1f1b4650	526	static int ve_spc_cpufreq_probe(struct platform_device *pdev)
a0f950d3 SH	527	{
	528	int ret, i;
	529
a0f950d3 SH	530	set_switching_enabled(bL_switcher_get_enabled());
	531
	532	for (i = 0; i < MAX_CLUSTERS; i++)
	533	mutex_init(&cluster_lock[i]);
	534
bb8c26d9 VK	535	if (!is_bL_switching_enabled())
	536	ve_spc_cpufreq_driver.flags \|= CPUFREQ_IS_COOLING_DEV;
	537
1f1b4650	538	ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);
a0f950d3 SH	539	if (ret) {
a0f950d3 SH	540	pr_info("%s: Failed registering platform driver: %s, err: %d\n",
1f1b4650	541	__func__, ve_spc_cpufreq_driver.name, ret);
a0f950d3 SH	542	} else {
a0f950d3 SH	543	ret = __bLs_register_notifier();
1f1b4650 SH	544	if (ret)
	545	cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
	546	else
a0f950d3	547	pr_info("%s: Registered platform driver: %s\n",
1f1b4650	548	__func__, ve_spc_cpufreq_driver.name);
a0f950d3 SH	549	}
	550
	551	bL_switcher_put_enabled();
	552	return ret;
	553	}
	554
1f1b4650	555	static int ve_spc_cpufreq_remove(struct platform_device *pdev)
a0f950d3	556	{
a0f950d3 SH	557	bL_switcher_get_enabled();
a0f950d3 SH	558	__bLs_unregister_notifier();
1f1b4650	559	cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
a0f950d3 SH	560	bL_switcher_put_enabled();
a0f950d3 SH	561	pr_info("%s: Un-registered platform driver: %s\n", __func__,
1f1b4650	562	ve_spc_cpufreq_driver.name);
47ac9aa1 SK	563	return 0;
	564	}
	565
	566	static struct platform_driver ve_spc_cpufreq_platdrv = {
	567	.driver = {
	568	.name = "vexpress-spc-cpufreq",
47ac9aa1 SK	569	},
	570	.probe = ve_spc_cpufreq_probe,
	571	.remove = ve_spc_cpufreq_remove,
	572	};
	573	module_platform_driver(ve_spc_cpufreq_platdrv);
	574
d1518399	575	MODULE_ALIAS("platform:vexpress-spc-cpufreq");
a0f950d3 SH	576	MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
	577	MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
	578	MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
	579	MODULE_LICENSE("GPL v2");