[mirror_ubuntu-zesty-kernel.git] / drivers / cpufreq / ppc_cbe_cpufreq.c

/*
 * cpufreq driver for the cell processor
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
 *
 * 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/module.h>
#include <linux/of_platform.h>

#include <asm/machdep.h>
#include <asm/prom.h>
#include <asm/cell-regs.h>

#include "ppc_cbe_cpufreq.h"

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

/*
 * hardware specific functions
 */

static int set_pmode(unsigned int cpu, unsigned int slow_mode)
{
	int rc;

	if (cbe_cpufreq_has_pmi)
		rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode);
	else
		rc = cbe_cpufreq_set_pmode(cpu, slow_mode);

	pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu));

	return rc;
}

/*
 * cpufreq functions
 */

static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
	struct cpufreq_frequency_table *pos;
	const u32 *max_freqp;
	u32 max_freq;
	int 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);

	/*
	 * Let's check we can actually get to the CELL regs
	 */
	if (!cbe_get_cpu_pmd_regs(policy->cpu) ||
	    !cbe_get_cpu_mic_tm_regs(policy->cpu)) {
		pr_info("invalid CBE regs pointers for cpufreq\n");
		return -EINVAL;
	}

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

	of_node_put(cpu);

	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 */
	cpufreq_for_each_entry(pos, cbe_freqs) {
		pos->frequency = max_freq / pos->driver_data;
		pr_debug("%d: %d\n", (int)(pos - cbe_freqs), pos->frequency);
	}

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

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

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

#ifdef CONFIG_SMP
	cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
#endif

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

static int cbe_cpufreq_target(struct cpufreq_policy *policy,
			      unsigned int cbe_pmode_new)
{
	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].driver_data);

	return set_pmode(policy->cpu, cbe_pmode_new);
}

static struct cpufreq_driver cbe_cpufreq_driver = {
	.verify		= cpufreq_generic_frequency_table_verify,
	.target_index	= cbe_cpufreq_target,
	.init		= cbe_cpufreq_cpu_init,
	.name		= "cbe-cpufreq",
	.flags		= CPUFREQ_CONST_LOOPS,
};

/*
 * module init and destoy
 */

static int __init cbe_cpufreq_init(void)
{
	if (!machine_is(cell))
		return -ENODEV;

	return cpufreq_register_driver(&cbe_cpufreq_driver);
}

static void __exit cbe_cpufreq_exit(void)
{
	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	*
74889e41	4	* (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
36ca4ba4 CK	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>
7dfe293c	24	#include <linux/module.h>
d8caf74f JL	25	#include <linux/of_platform.h>
d8caf74f JL	26
4bd4aa19	27	#include <asm/machdep.h>
74889e41	28	#include <asm/prom.h>
eef686a0	29	#include <asm/cell-regs.h>
6eb1c377 VK	30
6eb1c377 VK	31	#include "ppc_cbe_cpufreq.h"
36ca4ba4	32
36ca4ba4 CK	33	/* the CBE supports an 8 step frequency scaling */
36ca4ba4 CK	34	static struct cpufreq_frequency_table cbe_freqs[] = {
7f4b0461 VK	35	{0, 1, 0},
	36	{0, 2, 0},
	37	{0, 3, 0},
	38	{0, 4, 0},
	39	{0, 5, 0},
	40	{0, 6, 0},
	41	{0, 8, 0},
	42	{0, 10, 0},
	43	{0, 0, CPUFREQ_TABLE_END},
36ca4ba4 CK	44	};
36ca4ba4 CK	45
36ca4ba4 CK	46	/*
	47	* hardware specific functions
	48	*/
	49
74889e41	50	static int set_pmode(unsigned int cpu, unsigned int slow_mode)
813f9072	51	{
1e21fd5a	52	int rc;
74889e41	53
813f9072	54	if (cbe_cpufreq_has_pmi)
74889e41	55	rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode);
1e21fd5a	56	else
74889e41	57	rc = cbe_cpufreq_set_pmode(cpu, slow_mode);
1e21fd5a	58
74889e41	59	pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu));
1e21fd5a CK	60
1e21fd5a CK	61	return rc;
5050063c CK	62	}
5050063c CK	63
36ca4ba4 CK	64	/*
	65	* cpufreq functions
	66	*/
	67
4bd4aa19	68	static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
36ca4ba4	69	{
041526f9	70	struct cpufreq_frequency_table *pos;
9c1a2bae SR	71	const u32 *max_freqp;
9c1a2bae SR	72	u32 max_freq;
041526f9	73	int cur_pmode;
36ca4ba4 CK	74	struct device_node *cpu;
	75
	76	cpu = of_get_cpu_node(policy->cpu, NULL);
	77
4bd4aa19	78	if (!cpu)
36ca4ba4 CK	79	return -ENODEV;
	80
	81	pr_debug("init cpufreq on CPU %d\n", policy->cpu);
	82
64bafa9d JCD	83	/*
	84	* Let's check we can actually get to the CELL regs
	85	*/
	86	if (!cbe_get_cpu_pmd_regs(policy->cpu) \|\|
	87	!cbe_get_cpu_mic_tm_regs(policy->cpu)) {
	88	pr_info("invalid CBE regs pointers for cpufreq\n");
	89	return -EINVAL;
	90	}
	91
9c1a2bae	92	max_freqp = of_get_property(cpu, "clock-frequency", NULL);
36ca4ba4	93
1e21fd5a CK	94	of_node_put(cpu);
1e21fd5a CK	95
9c1a2bae	96	if (!max_freqp)
36ca4ba4 CK	97	return -EINVAL;
36ca4ba4 CK	98
4bd4aa19	99	/* we need the freq in kHz */
9c1a2bae	100	max_freq = *max_freqp / 1000;
36ca4ba4	101
9c1a2bae	102	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
36ca4ba4 CK	103	pr_debug("initializing frequency table\n");
36ca4ba4 CK	104
4bd4aa19	105	/* initialize frequency table */
041526f9 SK	106	cpufreq_for_each_entry(pos, cbe_freqs) {
	107	pos->frequency = max_freq / pos->driver_data;
	108	pr_debug("%d: %d\n", (int)(pos - cbe_freqs), pos->frequency);
36ca4ba4 CK	109	}
36ca4ba4 CK	110
1e21fd5a CK	111	/* if DEBUG is enabled set_pmode() measures the latency
1e21fd5a CK	112	* of a transition */
36ca4ba4 CK	113	policy->cpuinfo.transition_latency = 25000;
36ca4ba4 CK	114
74889e41	115	cur_pmode = cbe_cpufreq_get_pmode(policy->cpu);
36ca4ba4 CK	116	pr_debug("current pmode is at %d\n",cur_pmode);
	117
	118	policy->cur = cbe_freqs[cur_pmode].frequency;
	119
	120	#ifdef CONFIG_SMP
cc1ba8ea	121	cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
36ca4ba4 CK	122	#endif
36ca4ba4 CK	123
1e21fd5a CK	124	/* this ensures that policy->cpuinfo_min
1e21fd5a CK	125	* and policy->cpuinfo_max are set correctly */
6b4147db	126	return cpufreq_table_validate_and_show(policy, cbe_freqs);
36ca4ba4 CK	127	}
36ca4ba4 CK	128
1e21fd5a	129	static int cbe_cpufreq_target(struct cpufreq_policy *policy,
9c0ebcf7	130	unsigned int cbe_pmode_new)
36ca4ba4	131	{
1e21fd5a CK	132	pr_debug("setting frequency for cpu %d to %d kHz, " \
1e21fd5a CK	133	"1/%d of max frequency\n",
36ca4ba4 CK	134	policy->cpu,
36ca4ba4 CK	135	cbe_freqs[cbe_pmode_new].frequency,
50701588	136	cbe_freqs[cbe_pmode_new].driver_data);
36ca4ba4	137
d4019f0a	138	return set_pmode(policy->cpu, cbe_pmode_new);
36ca4ba4 CK	139	}
	140
	141	static struct cpufreq_driver cbe_cpufreq_driver = {
c3bc3d67	142	.verify = cpufreq_generic_frequency_table_verify,
9c0ebcf7	143	.target_index = cbe_cpufreq_target,
36ca4ba4	144	.init = cbe_cpufreq_cpu_init,
36ca4ba4	145	.name = "cbe-cpufreq",
36ca4ba4 CK	146	.flags = CPUFREQ_CONST_LOOPS,
	147	};
	148
	149	/*
	150	* module init and destoy
	151	*/
	152
	153	static int __init cbe_cpufreq_init(void)
	154	{
4bd4aa19 OJ	155	if (!machine_is(cell))
4bd4aa19 OJ	156	return -ENODEV;
5050063c	157
36ca4ba4 CK	158	return cpufreq_register_driver(&cbe_cpufreq_driver);
	159	}
	160
	161	static void __exit cbe_cpufreq_exit(void)
	162	{
	163	cpufreq_unregister_driver(&cbe_cpufreq_driver);
	164	}
	165
	166	module_init(cbe_cpufreq_init);
	167	module_exit(cbe_cpufreq_exit);
	168
	169	MODULE_LICENSE("GPL");
	170	MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");