[mirror_ubuntu-artful-kernel.git] / drivers / cpufreq / powernv-cpufreq.c

/*
 * POWERNV cpufreq driver for the IBM POWER processors
 *
 * (C) Copyright IBM 2014
 *
 * Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; 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)	"powernv-cpufreq: " fmt

#include <linux/kernel.h>
#include <linux/sysfs.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/cpufreq.h>
#include <linux/smp.h>
#include <linux/of.h>

#include <asm/cputhreads.h>
#include <asm/reg.h>
#include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */

#define POWERNV_MAX_PSTATES	256

static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];

/*
 * Note: The set of pstates consists of contiguous integers, the
 * smallest of which is indicated by powernv_pstate_info.min, the
 * largest of which is indicated by powernv_pstate_info.max.
 *
 * The nominal pstate is the highest non-turbo pstate in this
 * platform. This is indicated by powernv_pstate_info.nominal.
 */
static struct powernv_pstate_info {
	int min;
	int max;
	int nominal;
	int nr_pstates;
} powernv_pstate_info;

/*
 * Initialize the freq table based on data obtained
 * from the firmware passed via device-tree
 */
static int init_powernv_pstates(void)
{
	struct device_node *power_mgt;
	int i, pstate_min, pstate_max, pstate_nominal, nr_pstates = 0;
	const __be32 *pstate_ids, *pstate_freqs;
	u32 len_ids, len_freqs;

	power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
	if (!power_mgt) {
		pr_warn("power-mgt node not found\n");
		return -ENODEV;
	}

	if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
		pr_warn("ibm,pstate-min node not found\n");
		return -ENODEV;
	}

	if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
		pr_warn("ibm,pstate-max node not found\n");
		return -ENODEV;
	}

	if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
				 &pstate_nominal)) {
		pr_warn("ibm,pstate-nominal not found\n");
		return -ENODEV;
	}
	pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min,
		pstate_nominal, pstate_max);

	pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
	if (!pstate_ids) {
		pr_warn("ibm,pstate-ids not found\n");
		return -ENODEV;
	}

	pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
				      &len_freqs);
	if (!pstate_freqs) {
		pr_warn("ibm,pstate-frequencies-mhz not found\n");
		return -ENODEV;
	}

	WARN_ON(len_ids != len_freqs);
	nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
	if (!nr_pstates) {
		pr_warn("No PStates found\n");
		return -ENODEV;
	}

	pr_debug("NR PStates %d\n", nr_pstates);
	for (i = 0; i < nr_pstates; i++) {
		u32 id = be32_to_cpu(pstate_ids[i]);
		u32 freq = be32_to_cpu(pstate_freqs[i]);

		pr_debug("PState id %d freq %d MHz\n", id, freq);
		powernv_freqs[i].frequency = freq * 1000; /* kHz */
		powernv_freqs[i].driver_data = id;
	}
	/* End of list marker entry */
	powernv_freqs[i].frequency = CPUFREQ_TABLE_END;

	powernv_pstate_info.min = pstate_min;
	powernv_pstate_info.max = pstate_max;
	powernv_pstate_info.nominal = pstate_nominal;
	powernv_pstate_info.nr_pstates = nr_pstates;

	return 0;
}

/* Returns the CPU frequency corresponding to the pstate_id. */
static unsigned int pstate_id_to_freq(int pstate_id)
{
	int i;

	i = powernv_pstate_info.max - pstate_id;
	BUG_ON(i >= powernv_pstate_info.nr_pstates || i < 0);

	return powernv_freqs[i].frequency;
}

/*
 * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
 * the firmware
 */
static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
					char *buf)
{
	return sprintf(buf, "%u\n",
		pstate_id_to_freq(powernv_pstate_info.nominal));
}

struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
	__ATTR_RO(cpuinfo_nominal_freq);

static struct freq_attr *powernv_cpu_freq_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	&cpufreq_freq_attr_cpuinfo_nominal_freq,
	NULL,
};

/* Helper routines */

/* Access helpers to power mgt SPR */

static inline unsigned long get_pmspr(unsigned long sprn)
{
	switch (sprn) {
	case SPRN_PMCR:
		return mfspr(SPRN_PMCR);

	case SPRN_PMICR:
		return mfspr(SPRN_PMICR);

	case SPRN_PMSR:
		return mfspr(SPRN_PMSR);
	}
	BUG();
}

static inline void set_pmspr(unsigned long sprn, unsigned long val)
{
	switch (sprn) {
	case SPRN_PMCR:
		mtspr(SPRN_PMCR, val);
		return;

	case SPRN_PMICR:
		mtspr(SPRN_PMICR, val);
		return;
	}
	BUG();
}

/*
 * Use objects of this type to query/update
 * pstates on a remote CPU via smp_call_function.
 */
struct powernv_smp_call_data {
	unsigned int freq;
	int pstate_id;
};

/*
 * powernv_read_cpu_freq: Reads the current frequency on this CPU.
 *
 * Called via smp_call_function.
 *
 * Note: The caller of the smp_call_function should pass an argument of
 * the type 'struct powernv_smp_call_data *' along with this function.
 *
 * The current frequency on this CPU will be returned via
 * ((struct powernv_smp_call_data *)arg)->freq;
 */
static void powernv_read_cpu_freq(void *arg)
{
	unsigned long pmspr_val;
	s8 local_pstate_id;
	struct powernv_smp_call_data *freq_data = arg;

	pmspr_val = get_pmspr(SPRN_PMSR);

	/*
	 * The local pstate id corresponds bits 48..55 in the PMSR.
	 * Note: Watch out for the sign!
	 */
	local_pstate_id = (pmspr_val >> 48) & 0xFF;
	freq_data->pstate_id = local_pstate_id;
	freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);

	pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n",
		raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
		freq_data->freq);
}

/*
 * powernv_cpufreq_get: Returns the CPU frequency as reported by the
 * firmware for CPU 'cpu'. This value is reported through the sysfs
 * file cpuinfo_cur_freq.
 */
static unsigned int powernv_cpufreq_get(unsigned int cpu)
{
	struct powernv_smp_call_data freq_data;

	smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
			&freq_data, 1);

	return freq_data.freq;
}

/*
 * set_pstate: Sets the pstate on this CPU.
 *
 * This is called via an smp_call_function.
 *
 * The caller must ensure that freq_data is of the type
 * (struct powernv_smp_call_data *) and the pstate_id which needs to be set
 * on this CPU should be present in freq_data->pstate_id.
 */
static void set_pstate(void *freq_data)
{
	unsigned long val;
	unsigned long pstate_ul =
		((struct powernv_smp_call_data *) freq_data)->pstate_id;

	val = get_pmspr(SPRN_PMCR);
	val = val & 0x0000FFFFFFFFFFFFULL;

	pstate_ul = pstate_ul & 0xFF;

	/* Set both global(bits 56..63) and local(bits 48..55) PStates */
	val = val | (pstate_ul << 56) | (pstate_ul << 48);

	pr_debug("Setting cpu %d pmcr to %016lX\n",
			raw_smp_processor_id(), val);
	set_pmspr(SPRN_PMCR, val);
}

/*
 * powernv_cpufreq_target_index: Sets the frequency corresponding to
 * the cpufreq table entry indexed by new_index on the cpus in the
 * mask policy->cpus
 */
static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
					unsigned int new_index)
{
	struct powernv_smp_call_data freq_data;

	freq_data.pstate_id = powernv_freqs[new_index].driver_data;

	/*
	 * Use smp_call_function to send IPI and execute the
	 * mtspr on target CPU.  We could do that without IPI
	 * if current CPU is within policy->cpus (core)
	 */
	smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);

	return 0;
}

static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
	int base, i;

	base = cpu_first_thread_sibling(policy->cpu);

	for (i = 0; i < threads_per_core; i++)
		cpumask_set_cpu(base + i, policy->cpus);

	return cpufreq_table_validate_and_show(policy, powernv_freqs);
}

static struct cpufreq_driver powernv_cpufreq_driver = {
	.name		= "powernv-cpufreq",
	.flags		= CPUFREQ_CONST_LOOPS,
	.init		= powernv_cpufreq_cpu_init,
	.verify		= cpufreq_generic_frequency_table_verify,
	.target_index	= powernv_cpufreq_target_index,
	.get		= powernv_cpufreq_get,
	.attr		= powernv_cpu_freq_attr,
};

static int __init powernv_cpufreq_init(void)
{
	int rc = 0;

	/* Discover pstates from device tree and init */
	rc = init_powernv_pstates();
	if (rc) {
		pr_info("powernv-cpufreq disabled. System does not support PState control\n");
		return rc;
	}

	return cpufreq_register_driver(&powernv_cpufreq_driver);
}
module_init(powernv_cpufreq_init);

static void __exit powernv_cpufreq_exit(void)
{
	cpufreq_unregister_driver(&powernv_cpufreq_driver);
}
module_exit(powernv_cpufreq_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");
Commit	Line	Data
b3d627a5 VS	1	/*
	2	* POWERNV cpufreq driver for the IBM POWER processors
	3	*
	4	* (C) Copyright IBM 2014
	5	*
	6	* Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2, or (at your option)
	11	* any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	*/
	19
	20	#define pr_fmt(fmt) "powernv-cpufreq: " fmt
	21
	22	#include <linux/kernel.h>
	23	#include <linux/sysfs.h>
	24	#include <linux/cpumask.h>
	25	#include <linux/module.h>
	26	#include <linux/cpufreq.h>
	27	#include <linux/smp.h>
	28	#include <linux/of.h>
	29
	30	#include <asm/cputhreads.h>
	31	#include <asm/reg.h>
f3cae355	32	#include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
b3d627a5 VS	33
	34	#define POWERNV_MAX_PSTATES 256
	35
	36	static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
b3d627a5 VS	37
	38	/*
	39	* Note: The set of pstates consists of contiguous integers, the
	40	* smallest of which is indicated by powernv_pstate_info.min, the
	41	* largest of which is indicated by powernv_pstate_info.max.
	42	*
	43	* The nominal pstate is the highest non-turbo pstate in this
	44	* platform. This is indicated by powernv_pstate_info.nominal.
	45	*/
	46	static struct powernv_pstate_info {
	47	int min;
	48	int max;
	49	int nominal;
	50	int nr_pstates;
	51	} powernv_pstate_info;
	52
	53	/*
	54	* Initialize the freq table based on data obtained
	55	* from the firmware passed via device-tree
	56	*/
	57	static int init_powernv_pstates(void)
	58	{
	59	struct device_node *power_mgt;
	60	int i, pstate_min, pstate_max, pstate_nominal, nr_pstates = 0;
	61	const __be32 pstate_ids, pstate_freqs;
	62	u32 len_ids, len_freqs;
	63
	64	power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
	65	if (!power_mgt) {
	66	pr_warn("power-mgt node not found\n");
	67	return -ENODEV;
	68	}
	69
	70	if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
	71	pr_warn("ibm,pstate-min node not found\n");
	72	return -ENODEV;
	73	}
	74
	75	if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
	76	pr_warn("ibm,pstate-max node not found\n");
	77	return -ENODEV;
	78	}
	79
	80	if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
	81	&pstate_nominal)) {
	82	pr_warn("ibm,pstate-nominal not found\n");
	83	return -ENODEV;
	84	}
	85	pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min,
	86	pstate_nominal, pstate_max);
	87
	88	pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
	89	if (!pstate_ids) {
	90	pr_warn("ibm,pstate-ids not found\n");
	91	return -ENODEV;
	92	}
	93
	94	pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
	95	&len_freqs);
	96	if (!pstate_freqs) {
	97	pr_warn("ibm,pstate-frequencies-mhz not found\n");
	98	return -ENODEV;
	99	}
	100
101	WARN_ON(len_ids != len_freqs);
102	nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
103	if (!nr_pstates) {
104	pr_warn("No PStates found\n");
105	return -ENODEV;
106	}
107
108	pr_debug("NR PStates %d\n", nr_pstates);
109	for (i = 0; i < nr_pstates; i++) {
110	u32 id = be32_to_cpu(pstate_ids[i]);
111	u32 freq = be32_to_cpu(pstate_freqs[i]);
112
113	pr_debug("PState id %d freq %d MHz\n", id, freq);
114	powernv_freqs[i].frequency = freq * 1000; /* kHz */
0692c691	115	powernv_freqs[i].driver_data = id;
b3d627a5 VS	116	}
	117	/* End of list marker entry */
	118	powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
	119
	120	powernv_pstate_info.min = pstate_min;
	121	powernv_pstate_info.max = pstate_max;
	122	powernv_pstate_info.nominal = pstate_nominal;
	123	powernv_pstate_info.nr_pstates = nr_pstates;
	124
	125	return 0;
	126	}
	127
	128	/* Returns the CPU frequency corresponding to the pstate_id. */
	129	static unsigned int pstate_id_to_freq(int pstate_id)
	130	{
	131	int i;
	132
	133	i = powernv_pstate_info.max - pstate_id;
	134	BUG_ON(i >= powernv_pstate_info.nr_pstates \|\| i < 0);
	135
	136	return powernv_freqs[i].frequency;
	137	}
	138
	139	/*
	140	* cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
	141	* the firmware
	142	*/
	143	static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
	144	char *buf)
	145	{
	146	return sprintf(buf, "%u\n",
	147	pstate_id_to_freq(powernv_pstate_info.nominal));
	148	}
	149
	150	struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
	151	__ATTR_RO(cpuinfo_nominal_freq);
	152
	153	static struct freq_attr *powernv_cpu_freq_attr[] = {
	154	&cpufreq_freq_attr_scaling_available_freqs,
	155	&cpufreq_freq_attr_cpuinfo_nominal_freq,
	156	NULL,
	157	};
	158
	159	/* Helper routines */
	160
	161	/* Access helpers to power mgt SPR */
	162
	163	static inline unsigned long get_pmspr(unsigned long sprn)
	164	{
	165	switch (sprn) {
	166	case SPRN_PMCR:
	167	return mfspr(SPRN_PMCR);
	168
	169	case SPRN_PMICR:
	170	return mfspr(SPRN_PMICR);
	171
	172	case SPRN_PMSR:
	173	return mfspr(SPRN_PMSR);
	174	}
	175	BUG();
	176	}
	177
	178	static inline void set_pmspr(unsigned long sprn, unsigned long val)
	179	{
180	switch (sprn) {
181	case SPRN_PMCR:
182	mtspr(SPRN_PMCR, val);
183	return;
184
185	case SPRN_PMICR:
186	mtspr(SPRN_PMICR, val);
187	return;
188	}
189	BUG();
190	}
191
192	/*
193	* Use objects of this type to query/update
194	* pstates on a remote CPU via smp_call_function.
195	*/
196	struct powernv_smp_call_data {
197	unsigned int freq;
198	int pstate_id;
199	};
200
201	/*
202	* powernv_read_cpu_freq: Reads the current frequency on this CPU.
203	*
204	* Called via smp_call_function.
205	*
206	* Note: The caller of the smp_call_function should pass an argument of
207	* the type 'struct powernv_smp_call_data *' along with this function.
208	*
209	* The current frequency on this CPU will be returned via
210	* ((struct powernv_smp_call_data *)arg)->freq;
211	*/
212	static void powernv_read_cpu_freq(void *arg)
213	{
214	unsigned long pmspr_val;
215	s8 local_pstate_id;
216	struct powernv_smp_call_data *freq_data = arg;
217
218	pmspr_val = get_pmspr(SPRN_PMSR);
219
220	/*
221	* The local pstate id corresponds bits 48..55 in the PMSR.
222	* Note: Watch out for the sign!
223	*/
224	local_pstate_id = (pmspr_val >> 48) & 0xFF;
225	freq_data->pstate_id = local_pstate_id;
226	freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
227
228	pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n",
229	raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
230	freq_data->freq);
231	}
232
233	/*
234	* powernv_cpufreq_get: Returns the CPU frequency as reported by the
235	* firmware for CPU 'cpu'. This value is reported through the sysfs
236	* file cpuinfo_cur_freq.
237	*/
60d1ea4e	238	static unsigned int powernv_cpufreq_get(unsigned int cpu)
b3d627a5 VS	239	{
	240	struct powernv_smp_call_data freq_data;
	241
	242	smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
	243	&freq_data, 1);
	244
	245	return freq_data.freq;
	246	}
	247
	248	/*
	249	* set_pstate: Sets the pstate on this CPU.
	250	*
	251	* This is called via an smp_call_function.
	252	*
	253	* The caller must ensure that freq_data is of the type
	254	* (struct powernv_smp_call_data *) and the pstate_id which needs to be set
	255	* on this CPU should be present in freq_data->pstate_id.
	256	*/
	257	static void set_pstate(void *freq_data)
	258	{
	259	unsigned long val;
	260	unsigned long pstate_ul =
	261	((struct powernv_smp_call_data *) freq_data)->pstate_id;
	262
	263	val = get_pmspr(SPRN_PMCR);
	264	val = val & 0x0000FFFFFFFFFFFFULL;
	265
	266	pstate_ul = pstate_ul & 0xFF;
	267
	268	/* Set both global(bits 56..63) and local(bits 48..55) PStates */
	269	val = val \| (pstate_ul << 56) \| (pstate_ul << 48);
	270
	271	pr_debug("Setting cpu %d pmcr to %016lX\n",
	272	raw_smp_processor_id(), val);
	273	set_pmspr(SPRN_PMCR, val);
	274	}
	275
	276	/*
	277	* powernv_cpufreq_target_index: Sets the frequency corresponding to
	278	* the cpufreq table entry indexed by new_index on the cpus in the
	279	* mask policy->cpus
	280	*/
	281	static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
	282	unsigned int new_index)
	283	{
	284	struct powernv_smp_call_data freq_data;
	285
0692c691	286	freq_data.pstate_id = powernv_freqs[new_index].driver_data;
b3d627a5 VS	287
	288	/*
	289	* Use smp_call_function to send IPI and execute the
	290	* mtspr on target CPU. We could do that without IPI
	291	* if current CPU is within policy->cpus (core)
	292	*/
	293	smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
	294
	295	return 0;
	296	}
	297
	298	static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
	299	{
	300	int base, i;
	301
	302	base = cpu_first_thread_sibling(policy->cpu);
	303
	304	for (i = 0; i < threads_per_core; i++)
	305	cpumask_set_cpu(base + i, policy->cpus);
	306
	307	return cpufreq_table_validate_and_show(policy, powernv_freqs);
	308	}
	309
	310	static struct cpufreq_driver powernv_cpufreq_driver = {
	311	.name = "powernv-cpufreq",
	312	.flags = CPUFREQ_CONST_LOOPS,
	313	.init = powernv_cpufreq_cpu_init,
	314	.verify = cpufreq_generic_frequency_table_verify,
	315	.target_index = powernv_cpufreq_target_index,
	316	.get = powernv_cpufreq_get,
	317	.attr = powernv_cpu_freq_attr,
	318	};
	319
	320	static int __init powernv_cpufreq_init(void)
	321	{
	322	int rc = 0;
	323
	324	/* Discover pstates from device tree and init */
	325	rc = init_powernv_pstates();
	326	if (rc) {
	327	pr_info("powernv-cpufreq disabled. System does not support PState control\n");
	328	return rc;
	329	}
	330
	331	return cpufreq_register_driver(&powernv_cpufreq_driver);
	332	}
	333	module_init(powernv_cpufreq_init);
	334
	335	static void __exit powernv_cpufreq_exit(void)
	336	{
	337	cpufreq_unregister_driver(&powernv_cpufreq_driver);
	338	}
	339	module_exit(powernv_cpufreq_exit);
	340
	341	MODULE_LICENSE("GPL");
	342	MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");