[deliverable/linux.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 <linux/reboot.h>

#include <asm/cputhreads.h>
#include <asm/firmware.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];
static bool rebooting;

/*
 * 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;
	}

	if (len_ids != len_freqs) {
		pr_warn("Entries in ibm,pstate-ids and "
			"ibm,pstate-frequencies-mhz does not match\n");
	}

	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;
	if (i >= powernv_pstate_info.nr_pstates || i < 0) {
		pr_warn("PState id %d outside of PState table, "
			"reporting nominal id %d instead\n",
			pstate_id, powernv_pstate_info.nominal);
		i = powernv_pstate_info.max - powernv_pstate_info.nominal;
	}

	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);
}

/*
 * get_nominal_index: Returns the index corresponding to the nominal
 * pstate in the cpufreq table
 */
static inline unsigned int get_nominal_index(void)
{
	return powernv_pstate_info.max - powernv_pstate_info.nominal;
}

/*
 * 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;

	if (unlikely(rebooting) && new_index != get_nominal_index())
		return 0;

	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 int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
				unsigned long action, void *unused)
{
	int cpu;
	struct cpufreq_policy cpu_policy;

	rebooting = true;
	for_each_online_cpu(cpu) {
		cpufreq_get_policy(&cpu_policy, cpu);
		powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
	}

	return NOTIFY_DONE;
}

static struct notifier_block powernv_cpufreq_reboot_nb = {
	.notifier_call = powernv_cpufreq_reboot_notifier,
};

static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
{
	struct powernv_smp_call_data freq_data;

	freq_data.pstate_id = powernv_pstate_info.min;
	smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
}

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,
	.stop_cpu	= powernv_cpufreq_stop_cpu,
	.attr		= powernv_cpu_freq_attr,
};

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

	/* Don't probe on pseries (guest) platforms */
	if (!firmware_has_feature(FW_FEATURE_OPALv3))
		return -ENODEV;

	/* 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;
	}

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

static void __exit powernv_cpufreq_exit(void)
{
	unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
	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>
cf30af76	29	#include <linux/reboot.h>
b3d627a5 VS	30
b3d627a5 VS	31	#include <asm/cputhreads.h>
6174bac8	32	#include <asm/firmware.h>
b3d627a5	33	#include <asm/reg.h>
f3cae355	34	#include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
b3d627a5 VS	35
	36	#define POWERNV_MAX_PSTATES 256
	37
	38	static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
cf30af76	39	static bool rebooting;
b3d627a5 VS	40
	41	/*
	42	* Note: The set of pstates consists of contiguous integers, the
	43	* smallest of which is indicated by powernv_pstate_info.min, the
	44	* largest of which is indicated by powernv_pstate_info.max.
	45	*
	46	* The nominal pstate is the highest non-turbo pstate in this
	47	* platform. This is indicated by powernv_pstate_info.nominal.
	48	*/
	49	static struct powernv_pstate_info {
	50	int min;
	51	int max;
	52	int nominal;
	53	int nr_pstates;
	54	} powernv_pstate_info;
	55
	56	/*
	57	* Initialize the freq table based on data obtained
	58	* from the firmware passed via device-tree
	59	*/
	60	static int init_powernv_pstates(void)
	61	{
	62	struct device_node *power_mgt;
	63	int i, pstate_min, pstate_max, pstate_nominal, nr_pstates = 0;
	64	const __be32 pstate_ids, pstate_freqs;
	65	u32 len_ids, len_freqs;
	66
	67	power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
	68	if (!power_mgt) {
	69	pr_warn("power-mgt node not found\n");
	70	return -ENODEV;
	71	}
	72
	73	if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
	74	pr_warn("ibm,pstate-min node not found\n");
	75	return -ENODEV;
	76	}
	77
	78	if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
	79	pr_warn("ibm,pstate-max node not found\n");
	80	return -ENODEV;
	81	}
	82
	83	if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
	84	&pstate_nominal)) {
	85	pr_warn("ibm,pstate-nominal not found\n");
	86	return -ENODEV;
	87	}
	88	pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min,
	89	pstate_nominal, pstate_max);
	90
	91	pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
	92	if (!pstate_ids) {
	93	pr_warn("ibm,pstate-ids not found\n");
	94	return -ENODEV;
	95	}
	96
	97	pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
	98	&len_freqs);
	99	if (!pstate_freqs) {
	100	pr_warn("ibm,pstate-frequencies-mhz not found\n");
	101	return -ENODEV;
	102	}
	103
6174bac8 VS	104	if (len_ids != len_freqs) {
	105	pr_warn("Entries in ibm,pstate-ids and "
	106	"ibm,pstate-frequencies-mhz does not match\n");
	107	}
	108
b3d627a5 VS	109	nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
	110	if (!nr_pstates) {
	111	pr_warn("No PStates found\n");
	112	return -ENODEV;
	113	}
	114
	115	pr_debug("NR PStates %d\n", nr_pstates);
	116	for (i = 0; i < nr_pstates; i++) {
	117	u32 id = be32_to_cpu(pstate_ids[i]);
	118	u32 freq = be32_to_cpu(pstate_freqs[i]);
	119
	120	pr_debug("PState id %d freq %d MHz\n", id, freq);
	121	powernv_freqs[i].frequency = freq * 1000; /* kHz */
0692c691	122	powernv_freqs[i].driver_data = id;
b3d627a5 VS	123	}
	124	/* End of list marker entry */
	125	powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
	126
	127	powernv_pstate_info.min = pstate_min;
	128	powernv_pstate_info.max = pstate_max;
	129	powernv_pstate_info.nominal = pstate_nominal;
	130	powernv_pstate_info.nr_pstates = nr_pstates;
	131
	132	return 0;
	133	}
	134
	135	/* Returns the CPU frequency corresponding to the pstate_id. */
	136	static unsigned int pstate_id_to_freq(int pstate_id)
	137	{
	138	int i;
	139
	140	i = powernv_pstate_info.max - pstate_id;
6174bac8 VS	141	if (i >= powernv_pstate_info.nr_pstates \|\| i < 0) {
	142	pr_warn("PState id %d outside of PState table, "
	143	"reporting nominal id %d instead\n",
	144	pstate_id, powernv_pstate_info.nominal);
	145	i = powernv_pstate_info.max - powernv_pstate_info.nominal;
	146	}
b3d627a5 VS	147
	148	return powernv_freqs[i].frequency;
	149	}
	150
	151	/*
	152	* cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
	153	* the firmware
	154	*/
	155	static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
	156	char *buf)
	157	{
	158	return sprintf(buf, "%u\n",
	159	pstate_id_to_freq(powernv_pstate_info.nominal));
	160	}
	161
	162	struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
	163	__ATTR_RO(cpuinfo_nominal_freq);
	164
	165	static struct freq_attr *powernv_cpu_freq_attr[] = {
	166	&cpufreq_freq_attr_scaling_available_freqs,
	167	&cpufreq_freq_attr_cpuinfo_nominal_freq,
	168	NULL,
	169	};
	170
	171	/* Helper routines */
	172
	173	/* Access helpers to power mgt SPR */
	174
	175	static inline unsigned long get_pmspr(unsigned long sprn)
	176	{
	177	switch (sprn) {
	178	case SPRN_PMCR:
	179	return mfspr(SPRN_PMCR);
	180
	181	case SPRN_PMICR:
	182	return mfspr(SPRN_PMICR);
	183
	184	case SPRN_PMSR:
	185	return mfspr(SPRN_PMSR);
	186	}
	187	BUG();
	188	}
	189
	190	static inline void set_pmspr(unsigned long sprn, unsigned long val)
	191	{
	192	switch (sprn) {
	193	case SPRN_PMCR:
	194	mtspr(SPRN_PMCR, val);
	195	return;
	196
	197	case SPRN_PMICR:
	198	mtspr(SPRN_PMICR, val);
	199	return;
	200	}
	201	BUG();
	202	}
	203
	204	/*
	205	* Use objects of this type to query/update
	206	* pstates on a remote CPU via smp_call_function.
	207	*/
	208	struct powernv_smp_call_data {
	209	unsigned int freq;
	210	int pstate_id;
211	};
212
213	/*
214	* powernv_read_cpu_freq: Reads the current frequency on this CPU.
215	*
216	* Called via smp_call_function.
217	*
218	* Note: The caller of the smp_call_function should pass an argument of
219	* the type 'struct powernv_smp_call_data *' along with this function.
220	*
221	* The current frequency on this CPU will be returned via
222	* ((struct powernv_smp_call_data *)arg)->freq;
223	*/
224	static void powernv_read_cpu_freq(void *arg)
225	{
226	unsigned long pmspr_val;
227	s8 local_pstate_id;
228	struct powernv_smp_call_data *freq_data = arg;
229
230	pmspr_val = get_pmspr(SPRN_PMSR);
231
232	/*
233	* The local pstate id corresponds bits 48..55 in the PMSR.
234	* Note: Watch out for the sign!
235	*/
236	local_pstate_id = (pmspr_val >> 48) & 0xFF;
237	freq_data->pstate_id = local_pstate_id;
238	freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
239
240	pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n",
241	raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
242	freq_data->freq);
243	}
244
245	/*
246	* powernv_cpufreq_get: Returns the CPU frequency as reported by the
247	* firmware for CPU 'cpu'. This value is reported through the sysfs
248	* file cpuinfo_cur_freq.
249	*/
60d1ea4e	250	static unsigned int powernv_cpufreq_get(unsigned int cpu)
b3d627a5 VS	251	{
	252	struct powernv_smp_call_data freq_data;
	253
	254	smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
	255	&freq_data, 1);
	256
	257	return freq_data.freq;
	258	}
	259
	260	/*
	261	* set_pstate: Sets the pstate on this CPU.
	262	*
	263	* This is called via an smp_call_function.
	264	*
	265	* The caller must ensure that freq_data is of the type
	266	* (struct powernv_smp_call_data *) and the pstate_id which needs to be set
	267	* on this CPU should be present in freq_data->pstate_id.
	268	*/
	269	static void set_pstate(void *freq_data)
	270	{
	271	unsigned long val;
	272	unsigned long pstate_ul =
	273	((struct powernv_smp_call_data *) freq_data)->pstate_id;
	274
	275	val = get_pmspr(SPRN_PMCR);
	276	val = val & 0x0000FFFFFFFFFFFFULL;
	277
	278	pstate_ul = pstate_ul & 0xFF;
	279
	280	/* Set both global(bits 56..63) and local(bits 48..55) PStates */
	281	val = val \| (pstate_ul << 56) \| (pstate_ul << 48);
	282
	283	pr_debug("Setting cpu %d pmcr to %016lX\n",
	284	raw_smp_processor_id(), val);
	285	set_pmspr(SPRN_PMCR, val);
	286	}
	287
cf30af76 SB	288	/*
	289	* get_nominal_index: Returns the index corresponding to the nominal
	290	* pstate in the cpufreq table
	291	*/
	292	static inline unsigned int get_nominal_index(void)
	293	{
	294	return powernv_pstate_info.max - powernv_pstate_info.nominal;
	295	}
	296
b3d627a5 VS	297	/*
	298	* powernv_cpufreq_target_index: Sets the frequency corresponding to
	299	* the cpufreq table entry indexed by new_index on the cpus in the
	300	* mask policy->cpus
	301	*/
	302	static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
	303	unsigned int new_index)
	304	{
	305	struct powernv_smp_call_data freq_data;
	306
cf30af76 SB	307	if (unlikely(rebooting) && new_index != get_nominal_index())
	308	return 0;
	309
0692c691	310	freq_data.pstate_id = powernv_freqs[new_index].driver_data;
b3d627a5 VS	311
	312	/*
	313	* Use smp_call_function to send IPI and execute the
	314	* mtspr on target CPU. We could do that without IPI
	315	* if current CPU is within policy->cpus (core)
	316	*/
	317	smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
	318
	319	return 0;
	320	}
	321
	322	static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
	323	{
	324	int base, i;
	325
	326	base = cpu_first_thread_sibling(policy->cpu);
	327
	328	for (i = 0; i < threads_per_core; i++)
	329	cpumask_set_cpu(base + i, policy->cpus);
	330
	331	return cpufreq_table_validate_and_show(policy, powernv_freqs);
	332	}
	333
cf30af76 SB	334	static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
	335	unsigned long action, void *unused)
	336	{
	337	int cpu;
	338	struct cpufreq_policy cpu_policy;
	339
	340	rebooting = true;
	341	for_each_online_cpu(cpu) {
	342	cpufreq_get_policy(&cpu_policy, cpu);
	343	powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
	344	}
	345
	346	return NOTIFY_DONE;
	347	}
	348
	349	static struct notifier_block powernv_cpufreq_reboot_nb = {
	350	.notifier_call = powernv_cpufreq_reboot_notifier,
	351	};
	352
b120339c PM	353	static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
	354	{
	355	struct powernv_smp_call_data freq_data;
	356
	357	freq_data.pstate_id = powernv_pstate_info.min;
	358	smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
	359	}
	360
b3d627a5 VS	361	static struct cpufreq_driver powernv_cpufreq_driver = {
	362	.name = "powernv-cpufreq",
	363	.flags = CPUFREQ_CONST_LOOPS,
	364	.init = powernv_cpufreq_cpu_init,
	365	.verify = cpufreq_generic_frequency_table_verify,
	366	.target_index = powernv_cpufreq_target_index,
	367	.get = powernv_cpufreq_get,
b120339c	368	.stop_cpu = powernv_cpufreq_stop_cpu,
b3d627a5 VS	369	.attr = powernv_cpu_freq_attr,
	370	};
	371
	372	static int __init powernv_cpufreq_init(void)
	373	{
	374	int rc = 0;
	375
6174bac8 VS	376	/* Don't probe on pseries (guest) platforms */
	377	if (!firmware_has_feature(FW_FEATURE_OPALv3))
	378	return -ENODEV;
	379
b3d627a5 VS	380	/* Discover pstates from device tree and init */
	381	rc = init_powernv_pstates();
	382	if (rc) {
	383	pr_info("powernv-cpufreq disabled. System does not support PState control\n");
	384	return rc;
	385	}
	386
cf30af76	387	register_reboot_notifier(&powernv_cpufreq_reboot_nb);
b3d627a5 VS	388	return cpufreq_register_driver(&powernv_cpufreq_driver);
	389	}
	390	module_init(powernv_cpufreq_init);
	391
	392	static void __exit powernv_cpufreq_exit(void)
	393	{
cf30af76	394	unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
b3d627a5 VS	395	cpufreq_unregister_driver(&powernv_cpufreq_driver);
	396	}
	397	module_exit(powernv_cpufreq_exit);
	398
	399	MODULE_LICENSE("GPL");
	400	MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");