[mirror_ubuntu-bionic-kernel.git] / arch / powerpc / platforms / cell / cbe_cpufreq.c

/*
 * cpufreq driver for the cell processor
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * Author: Christian Krafft <krafft@de.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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/cpufreq.h>
#include <linux/timer.h>

#include <asm/hw_irq.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/prom.h>
#include <asm/time.h>
#include <asm/pmi.h>
#include <asm/of_platform.h>

#include "cbe_regs.h"

static DEFINE_MUTEX(cbe_switch_mutex);


/* the CBE supports an 8 step frequency scaling */
static struct cpufreq_frequency_table cbe_freqs[] = {
	{1,	0},
	{2,	0},
	{3,	0},
	{4,	0},
	{5,	0},
	{6,	0},
	{8,	0},
	{10,	0},
	{0,	CPUFREQ_TABLE_END},
};

/* to write to MIC register */
static u64 MIC_Slow_Fast_Timer_table[] = {
	[0 ... 7] = 0x007fc00000000000ull,
};

/* more values for the MIC */
static u64 MIC_Slow_Next_Timer_table[] = {
	0x0000240000000000ull,
	0x0000268000000000ull,
	0x000029C000000000ull,
	0x00002D0000000000ull,
	0x0000300000000000ull,
	0x0000334000000000ull,
	0x000039C000000000ull,
	0x00003FC000000000ull,
};

/*
 * hardware specific functions
 */

static struct of_device *pmi_dev;

static int set_pmode_pmi(int cpu, unsigned int pmode)
{
	int ret;
	pmi_message_t pmi_msg;
#ifdef DEBUG
	u64 time;
#endif

	pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
	pmi_msg.data1 =	cbe_cpu_to_node(cpu);
	pmi_msg.data2 = pmode;

#ifdef DEBUG
	time = (u64) get_cycles();
#endif

	pmi_send_message(pmi_dev, pmi_msg);
	ret = pmi_msg.data2;

	pr_debug("PMI returned slow mode %d\n", ret);

#ifdef DEBUG
	time = (u64) get_cycles() - time; /* actual cycles (not cpu cycles!) */
	time = 1000000000 * time / CLOCK_TICK_RATE; /* time in ns (10^-9) */
	pr_debug("had to wait %lu ns for a transition\n", time);
#endif
	return ret;
}


static int get_pmode(int cpu)
{
	int ret;
	struct cbe_pmd_regs __iomem *pmd_regs;

	pmd_regs = cbe_get_cpu_pmd_regs(cpu);
	ret = in_be64(&pmd_regs->pmsr) & 0x07;

	return ret;
}

static int set_pmode_reg(int cpu, unsigned int pmode)
{
	struct cbe_pmd_regs __iomem *pmd_regs;
	struct cbe_mic_tm_regs __iomem *mic_tm_regs;
	u64 flags;
	u64 value;

	local_irq_save(flags);

	mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
	pmd_regs = cbe_get_cpu_pmd_regs(cpu);

	pr_debug("pm register is mapped at %p\n", &pmd_regs->pmcr);
	pr_debug("mic register is mapped at %p\n", &mic_tm_regs->slow_fast_timer_0);

	out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
	out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);

	out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
	out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);

	value = in_be64(&pmd_regs->pmcr);
	/* set bits to zero */
	value &= 0xFFFFFFFFFFFFFFF8ull;
	/* set bits to next pmode */
	value |= pmode;

	out_be64(&pmd_regs->pmcr, value);

	/* wait until new pmode appears in status register */
	value = in_be64(&pmd_regs->pmsr) & 0x07;
	while(value != pmode) {
		cpu_relax();
		value = in_be64(&pmd_regs->pmsr) & 0x07;
	}

	local_irq_restore(flags);

	return 0;
}

static int set_pmode(int cpu, unsigned int slow_mode) {
	if(pmi_dev)
		return set_pmode_pmi(cpu, slow_mode);
	else
		return set_pmode_reg(cpu, slow_mode);
}

static void cbe_cpufreq_handle_pmi(struct of_device *dev, pmi_message_t pmi_msg)
{
	struct cpufreq_policy policy;
	u8 cpu;
	u8 cbe_pmode_new;

	BUG_ON (pmi_msg.type != PMI_TYPE_FREQ_CHANGE);

	cpu = cbe_node_to_cpu(pmi_msg.data1);
	cbe_pmode_new = pmi_msg.data2;

	cpufreq_get_policy(&policy, cpu);

	policy.max = min(policy.max, cbe_freqs[cbe_pmode_new].frequency);
	policy.min = min(policy.min, policy.max);

	pr_debug("cbe_handle_pmi: new policy.min=%d policy.max=%d\n", policy.min, policy.max);
	cpufreq_set_policy(&policy);
}

static struct pmi_handler cbe_pmi_handler = {
	.type			= PMI_TYPE_FREQ_CHANGE,
	.handle_pmi_message	= cbe_cpufreq_handle_pmi,
};


/*
 * cpufreq functions
 */

static int cbe_cpufreq_cpu_init (struct cpufreq_policy *policy)
{
	const u32 *max_freqp;
	u32 max_freq;
	int i, cur_pmode;
	struct device_node *cpu;

	cpu = of_get_cpu_node(policy->cpu, NULL);

	if(!cpu)
		return -ENODEV;

	pr_debug("init cpufreq on CPU %d\n", policy->cpu);

	max_freqp = of_get_property(cpu, "clock-frequency", NULL);

	if (!max_freqp)
		return -EINVAL;

	// we need the freq in kHz
	max_freq = *max_freqp / 1000;

	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
	pr_debug("initializing frequency table\n");

	// initialize frequency table
	for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
		cbe_freqs[i].frequency = max_freq / cbe_freqs[i].index;
		pr_debug("%d: %d\n", i, cbe_freqs[i].frequency);
	}

	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
	/* if DEBUG is enabled set_pmode() measures the correct latency of a transition */
	policy->cpuinfo.transition_latency = 25000;

	cur_pmode = get_pmode(policy->cpu);
	pr_debug("current pmode is at %d\n",cur_pmode);

	policy->cur = cbe_freqs[cur_pmode].frequency;

#ifdef CONFIG_SMP
	policy->cpus = cpu_sibling_map[policy->cpu];
#endif

	cpufreq_frequency_table_get_attr (cbe_freqs, policy->cpu);

	/* this ensures that policy->cpuinfo_min and policy->cpuinfo_max are set correctly */
	return cpufreq_frequency_table_cpuinfo (policy, cbe_freqs);
}

static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
	cpufreq_frequency_table_put_attr(policy->cpu);
	return 0;
}

static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, cbe_freqs);
}


static int cbe_cpufreq_target(struct cpufreq_policy *policy, unsigned int target_freq,
			    unsigned int relation)
{
	int rc;
	struct cpufreq_freqs freqs;
	int cbe_pmode_new;

	cpufreq_frequency_table_target(policy,
				       cbe_freqs,
				       target_freq,
				       relation,
				       &cbe_pmode_new);

	freqs.old = policy->cur;
	freqs.new = cbe_freqs[cbe_pmode_new].frequency;
	freqs.cpu = policy->cpu;

	mutex_lock (&cbe_switch_mutex);
	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

	pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
		 policy->cpu,
		 cbe_freqs[cbe_pmode_new].frequency,
		 cbe_freqs[cbe_pmode_new].index);

	rc = set_pmode(policy->cpu, cbe_pmode_new);
	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	mutex_unlock(&cbe_switch_mutex);

	return rc;
}

static struct cpufreq_driver cbe_cpufreq_driver = {
	.verify		= cbe_cpufreq_verify,
	.target		= cbe_cpufreq_target,
	.init		= cbe_cpufreq_cpu_init,
	.exit		= cbe_cpufreq_cpu_exit,
	.name		= "cbe-cpufreq",
	.owner		= THIS_MODULE,
	.flags		= CPUFREQ_CONST_LOOPS,
};

/*
 * module init and destoy
 */

static int __init cbe_cpufreq_init(void)
{
	struct device_node *np;

	np = of_find_node_by_type(NULL, "ibm,pmi");

	pmi_dev = of_find_device_by_node(np);

	if (pmi_dev)
		pmi_register_handler(pmi_dev, &cbe_pmi_handler);

	return cpufreq_register_driver(&cbe_cpufreq_driver);
}

static void __exit cbe_cpufreq_exit(void)
{
	if(pmi_dev)
		pmi_unregister_handler(pmi_dev, &cbe_pmi_handler);

	cpufreq_unregister_driver(&cbe_cpufreq_driver);
}

module_init(cbe_cpufreq_init);
module_exit(cbe_cpufreq_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
Commit	Line	Data
36ca4ba4 CK	1	/*
	2	* cpufreq driver for the cell processor
	3	*
	4	* (C) Copyright IBM Deutschland Entwicklung GmbH 2005
	5	*
	6	* Author: Christian Krafft <krafft@de.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	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to the Free Software
	20	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	21	*/
	22
	23	#include <linux/cpufreq.h>
	24	#include <linux/timer.h>
	25
	26	#include <asm/hw_irq.h>
	27	#include <asm/io.h>
	28	#include <asm/processor.h>
	29	#include <asm/prom.h>
	30	#include <asm/time.h>
5050063c CK	31	#include <asm/pmi.h>
5050063c CK	32	#include <asm/of_platform.h>
36ca4ba4 CK	33
	34	#include "cbe_regs.h"
	35
	36	static DEFINE_MUTEX(cbe_switch_mutex);
	37
	38
	39	/* the CBE supports an 8 step frequency scaling */
	40	static struct cpufreq_frequency_table cbe_freqs[] = {
	41	{1, 0},
	42	{2, 0},
	43	{3, 0},
	44	{4, 0},
	45	{5, 0},
	46	{6, 0},
	47	{8, 0},
	48	{10, 0},
	49	{0, CPUFREQ_TABLE_END},
	50	};
	51
	52	/* to write to MIC register */
	53	static u64 MIC_Slow_Fast_Timer_table[] = {
	54	[0 ... 7] = 0x007fc00000000000ull,
	55	};
	56
	57	/* more values for the MIC */
	58	static u64 MIC_Slow_Next_Timer_table[] = {
	59	0x0000240000000000ull,
	60	0x0000268000000000ull,
	61	0x000029C000000000ull,
	62	0x00002D0000000000ull,
	63	0x0000300000000000ull,
	64	0x0000334000000000ull,
	65	0x000039C000000000ull,
	66	0x00003FC000000000ull,
	67	};
	68
	69	/*
	70	* hardware specific functions
	71	*/
	72
5050063c CK	73	static struct of_device *pmi_dev;
	74
	75	static int set_pmode_pmi(int cpu, unsigned int pmode)
	76	{
	77	int ret;
	78	pmi_message_t pmi_msg;
	79	#ifdef DEBUG
	80	u64 time;
	81	#endif
	82
	83	pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
	84	pmi_msg.data1 = cbe_cpu_to_node(cpu);
	85	pmi_msg.data2 = pmode;
	86
	87	#ifdef DEBUG
	88	time = (u64) get_cycles();
	89	#endif
	90
	91	pmi_send_message(pmi_dev, pmi_msg);
	92	ret = pmi_msg.data2;
	93
	94	pr_debug("PMI returned slow mode %d\n", ret);
	95
	96	#ifdef DEBUG
	97	time = (u64) get_cycles() - time; /* actual cycles (not cpu cycles!) */
	98	time = 1000000000 * time / CLOCK_TICK_RATE; /* time in ns (10^-9) */
	99	pr_debug("had to wait %lu ns for a transition\n", time);
	100	#endif
	101	return ret;
	102	}
	103
	104
36ca4ba4 CK	105	static int get_pmode(int cpu)
	106	{
	107	int ret;
	108	struct cbe_pmd_regs __iomem *pmd_regs;
	109
	110	pmd_regs = cbe_get_cpu_pmd_regs(cpu);
	111	ret = in_be64(&pmd_regs->pmsr) & 0x07;
	112
	113	return ret;
	114	}
	115
5050063c	116	static int set_pmode_reg(int cpu, unsigned int pmode)
36ca4ba4 CK	117	{
	118	struct cbe_pmd_regs __iomem *pmd_regs;
	119	struct cbe_mic_tm_regs __iomem *mic_tm_regs;
	120	u64 flags;
	121	u64 value;
	122
	123	local_irq_save(flags);
	124
	125	mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
	126	pmd_regs = cbe_get_cpu_pmd_regs(cpu);
	127
	128	pr_debug("pm register is mapped at %p\n", &pmd_regs->pmcr);
	129	pr_debug("mic register is mapped at %p\n", &mic_tm_regs->slow_fast_timer_0);
	130
	131	out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
	132	out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
	133
	134	out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
	135	out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
	136
	137	value = in_be64(&pmd_regs->pmcr);
	138	/* set bits to zero */
	139	value &= 0xFFFFFFFFFFFFFFF8ull;
	140	/* set bits to next pmode */
	141	value \|= pmode;
	142
	143	out_be64(&pmd_regs->pmcr, value);
	144
	145	/* wait until new pmode appears in status register */
	146	value = in_be64(&pmd_regs->pmsr) & 0x07;
	147	while(value != pmode) {
	148	cpu_relax();
	149	value = in_be64(&pmd_regs->pmsr) & 0x07;
	150	}
	151
	152	local_irq_restore(flags);
	153
	154	return 0;
	155	}
	156
5050063c CK	157	static int set_pmode(int cpu, unsigned int slow_mode) {
	158	if(pmi_dev)
	159	return set_pmode_pmi(cpu, slow_mode);
	160	else
	161	return set_pmode_reg(cpu, slow_mode);
	162	}
	163
	164	static void cbe_cpufreq_handle_pmi(struct of_device *dev, pmi_message_t pmi_msg)
	165	{
	166	struct cpufreq_policy policy;
	167	u8 cpu;
	168	u8 cbe_pmode_new;
	169
	170	BUG_ON (pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
	171
	172	cpu = cbe_node_to_cpu(pmi_msg.data1);
	173	cbe_pmode_new = pmi_msg.data2;
	174
	175	cpufreq_get_policy(&policy, cpu);
	176
	177	policy.max = min(policy.max, cbe_freqs[cbe_pmode_new].frequency);
	178	policy.min = min(policy.min, policy.max);
	179
	180	pr_debug("cbe_handle_pmi: new policy.min=%d policy.max=%d\n", policy.min, policy.max);
	181	cpufreq_set_policy(&policy);
	182	}
	183
	184	static struct pmi_handler cbe_pmi_handler = {
	185	.type = PMI_TYPE_FREQ_CHANGE,
	186	.handle_pmi_message = cbe_cpufreq_handle_pmi,
	187	};
	188
	189
36ca4ba4 CK	190	/*
	191	* cpufreq functions
	192	*/
	193
	194	static int cbe_cpufreq_cpu_init (struct cpufreq_policy *policy)
	195	{
9c1a2bae SR	196	const u32 *max_freqp;
9c1a2bae SR	197	u32 max_freq;
36ca4ba4 CK	198	int i, cur_pmode;
	199	struct device_node *cpu;
	200
	201	cpu = of_get_cpu_node(policy->cpu, NULL);
	202
	203	if(!cpu)
	204	return -ENODEV;
	205
	206	pr_debug("init cpufreq on CPU %d\n", policy->cpu);
	207
9c1a2bae	208	max_freqp = of_get_property(cpu, "clock-frequency", NULL);
36ca4ba4	209
9c1a2bae	210	if (!max_freqp)
36ca4ba4 CK	211	return -EINVAL;
	212
	213	// we need the freq in kHz
9c1a2bae	214	max_freq = *max_freqp / 1000;
36ca4ba4	215
9c1a2bae	216	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
36ca4ba4 CK	217	pr_debug("initializing frequency table\n");
	218
	219	// initialize frequency table
	220	for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
9c1a2bae	221	cbe_freqs[i].frequency = max_freq / cbe_freqs[i].index;
36ca4ba4 CK	222	pr_debug("%d: %d\n", i, cbe_freqs[i].frequency);
	223	}
	224
	225	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
	226	/* if DEBUG is enabled set_pmode() measures the correct latency of a transition */
	227	policy->cpuinfo.transition_latency = 25000;
	228
	229	cur_pmode = get_pmode(policy->cpu);
	230	pr_debug("current pmode is at %d\n",cur_pmode);
	231
	232	policy->cur = cbe_freqs[cur_pmode].frequency;
	233
	234	#ifdef CONFIG_SMP
	235	policy->cpus = cpu_sibling_map[policy->cpu];
	236	#endif
	237
	238	cpufreq_frequency_table_get_attr (cbe_freqs, policy->cpu);
	239
	240	/* this ensures that policy->cpuinfo_min and policy->cpuinfo_max are set correctly */
	241	return cpufreq_frequency_table_cpuinfo (policy, cbe_freqs);
	242	}
	243
	244	static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
	245	{
	246	cpufreq_frequency_table_put_attr(policy->cpu);
	247	return 0;
	248	}
	249
	250	static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
	251	{
	252	return cpufreq_frequency_table_verify(policy, cbe_freqs);
	253	}
	254
	255
	256	static int cbe_cpufreq_target(struct cpufreq_policy *policy, unsigned int target_freq,
	257	unsigned int relation)
	258	{
	259	int rc;
	260	struct cpufreq_freqs freqs;
	261	int cbe_pmode_new;
	262
	263	cpufreq_frequency_table_target(policy,
	264	cbe_freqs,
	265	target_freq,
	266	relation,
	267	&cbe_pmode_new);
	268
	269	freqs.old = policy->cur;
	270	freqs.new = cbe_freqs[cbe_pmode_new].frequency;
	271	freqs.cpu = policy->cpu;
	272
	273	mutex_lock (&cbe_switch_mutex);
	274	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	275
	276	pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
	277	policy->cpu,
	278	cbe_freqs[cbe_pmode_new].frequency,
	279	cbe_freqs[cbe_pmode_new].index);
	280
	281	rc = set_pmode(policy->cpu, cbe_pmode_new);
	282	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	283	mutex_unlock(&cbe_switch_mutex);
	284
	285	return rc;
286	}
287
288	static struct cpufreq_driver cbe_cpufreq_driver = {
289	.verify = cbe_cpufreq_verify,
290	.target = cbe_cpufreq_target,
291	.init = cbe_cpufreq_cpu_init,
292	.exit = cbe_cpufreq_cpu_exit,
293	.name = "cbe-cpufreq",
294	.owner = THIS_MODULE,
295	.flags = CPUFREQ_CONST_LOOPS,
296	};
297
298	/*
299	* module init and destoy
300	*/
301
302	static int __init cbe_cpufreq_init(void)
303	{
5050063c CK	304	struct device_node *np;
	305
	306	np = of_find_node_by_type(NULL, "ibm,pmi");
	307
	308	pmi_dev = of_find_device_by_node(np);
	309
	310	if (pmi_dev)
	311	pmi_register_handler(pmi_dev, &cbe_pmi_handler);
	312
36ca4ba4 CK	313	return cpufreq_register_driver(&cbe_cpufreq_driver);
	314	}
	315
	316	static void __exit cbe_cpufreq_exit(void)
	317	{
5050063c CK	318	if(pmi_dev)
	319	pmi_unregister_handler(pmi_dev, &cbe_pmi_handler);
	320
36ca4ba4 CK	321	cpufreq_unregister_driver(&cbe_cpufreq_driver);
	322	}
	323
	324	module_init(cbe_cpufreq_init);
	325	module_exit(cbe_cpufreq_exit);
	326
	327	MODULE_LICENSE("GPL");
	328	MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");