[linux-block.git] / drivers / cpufreq / ppc_cbe_cpufreq.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * cpufreq driver for the cell processor
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
 *
 * Author: Christian Krafft <krafft@de.ibm.com>
 */

#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/of_platform.h>

#include <asm/machdep.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");
		of_node_put(cpu);
		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

	policy->freq_table = cbe_freqs;
	cbe_cpufreq_pmi_policy_init(policy);
	return 0;
}

static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
	cbe_cpufreq_pmi_policy_exit(policy);
	return 0;
}

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,
	.exit		= cbe_cpufreq_cpu_exit,
	.name		= "cbe-cpufreq",
	.flags		= CPUFREQ_CONST_LOOPS,
};

/*
 * module init and destoy
 */

static int __init cbe_cpufreq_init(void)
{
	int ret;

	if (!machine_is(cell))
		return -ENODEV;

	cbe_cpufreq_pmi_init();

	ret = cpufreq_register_driver(&cbe_cpufreq_driver);
	if (ret)
		cbe_cpufreq_pmi_exit();

	return ret;
}

static void __exit cbe_cpufreq_exit(void)
{
	cpufreq_unregister_driver(&cbe_cpufreq_driver);
	cbe_cpufreq_pmi_exit();
}

module_init(cbe_cpufreq_init);
module_exit(cbe_cpufreq_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
Commit	Line	Data
de6cc651	1	// SPDX-License-Identifier: GPL-2.0-or-later
36ca4ba4 CK	2	/*
	3	* cpufreq driver for the cell processor
	4	*
74889e41	5	* (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
36ca4ba4 CK	6	*
36ca4ba4 CK	7	* Author: Christian Krafft <krafft@de.ibm.com>
36ca4ba4 CK	8	*/
	9
	10	#include <linux/cpufreq.h>
7dfe293c	11	#include <linux/module.h>
d8caf74f JL	12	#include <linux/of_platform.h>
d8caf74f JL	13
4bd4aa19	14	#include <asm/machdep.h>
eef686a0	15	#include <asm/cell-regs.h>
6eb1c377 VK	16
6eb1c377 VK	17	#include "ppc_cbe_cpufreq.h"
36ca4ba4	18
36ca4ba4 CK	19	/* the CBE supports an 8 step frequency scaling */
36ca4ba4 CK	20	static struct cpufreq_frequency_table cbe_freqs[] = {
7f4b0461 VK	21	{0, 1, 0},
	22	{0, 2, 0},
	23	{0, 3, 0},
	24	{0, 4, 0},
	25	{0, 5, 0},
	26	{0, 6, 0},
	27	{0, 8, 0},
	28	{0, 10, 0},
	29	{0, 0, CPUFREQ_TABLE_END},
36ca4ba4 CK	30	};
36ca4ba4 CK	31
36ca4ba4 CK	32	/*
	33	* hardware specific functions
	34	*/
	35
74889e41	36	static int set_pmode(unsigned int cpu, unsigned int slow_mode)
813f9072	37	{
1e21fd5a	38	int rc;
74889e41	39
813f9072	40	if (cbe_cpufreq_has_pmi)
74889e41	41	rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode);
1e21fd5a	42	else
74889e41	43	rc = cbe_cpufreq_set_pmode(cpu, slow_mode);
1e21fd5a	44
74889e41	45	pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu));
1e21fd5a CK	46
1e21fd5a CK	47	return rc;
5050063c CK	48	}
5050063c CK	49
36ca4ba4 CK	50	/*
	51	* cpufreq functions
	52	*/
	53
4bd4aa19	54	static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
36ca4ba4	55	{
041526f9	56	struct cpufreq_frequency_table *pos;
9c1a2bae SR	57	const u32 *max_freqp;
9c1a2bae SR	58	u32 max_freq;
041526f9	59	int cur_pmode;
36ca4ba4 CK	60	struct device_node *cpu;
	61
	62	cpu = of_get_cpu_node(policy->cpu, NULL);
	63
4bd4aa19	64	if (!cpu)
36ca4ba4 CK	65	return -ENODEV;
	66
	67	pr_debug("init cpufreq on CPU %d\n", policy->cpu);
	68
64bafa9d JCD	69	/*
	70	* Let's check we can actually get to the CELL regs
	71	*/
	72	if (!cbe_get_cpu_pmd_regs(policy->cpu) \|\|
	73	!cbe_get_cpu_mic_tm_regs(policy->cpu)) {
	74	pr_info("invalid CBE regs pointers for cpufreq\n");
23329803	75	of_node_put(cpu);
64bafa9d JCD	76	return -EINVAL;
	77	}
	78
9c1a2bae	79	max_freqp = of_get_property(cpu, "clock-frequency", NULL);
36ca4ba4	80
1e21fd5a CK	81	of_node_put(cpu);
1e21fd5a CK	82
9c1a2bae	83	if (!max_freqp)
36ca4ba4 CK	84	return -EINVAL;
36ca4ba4 CK	85
4bd4aa19	86	/* we need the freq in kHz */
9c1a2bae	87	max_freq = *max_freqp / 1000;
36ca4ba4	88
9c1a2bae	89	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
36ca4ba4 CK	90	pr_debug("initializing frequency table\n");
36ca4ba4 CK	91
4bd4aa19	92	/* initialize frequency table */
041526f9 SK	93	cpufreq_for_each_entry(pos, cbe_freqs) {
	94	pos->frequency = max_freq / pos->driver_data;
	95	pr_debug("%d: %d\n", (int)(pos - cbe_freqs), pos->frequency);
36ca4ba4 CK	96	}
36ca4ba4 CK	97
1e21fd5a CK	98	/* if DEBUG is enabled set_pmode() measures the latency
1e21fd5a CK	99	* of a transition */
36ca4ba4 CK	100	policy->cpuinfo.transition_latency = 25000;
36ca4ba4 CK	101
74889e41	102	cur_pmode = cbe_cpufreq_get_pmode(policy->cpu);
36ca4ba4 CK	103	pr_debug("current pmode is at %d\n",cur_pmode);
	104
	105	policy->cur = cbe_freqs[cur_pmode].frequency;
	106
	107	#ifdef CONFIG_SMP
cc1ba8ea	108	cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
36ca4ba4 CK	109	#endif
36ca4ba4 CK	110
20dfdb9c	111	policy->freq_table = cbe_freqs;
afe96907 VK	112	cbe_cpufreq_pmi_policy_init(policy);
	113	return 0;
	114	}
	115
	116	static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
	117	{
	118	cbe_cpufreq_pmi_policy_exit(policy);
20dfdb9c	119	return 0;
36ca4ba4 CK	120	}
36ca4ba4 CK	121
1e21fd5a	122	static int cbe_cpufreq_target(struct cpufreq_policy *policy,
9c0ebcf7	123	unsigned int cbe_pmode_new)
36ca4ba4	124	{
1e21fd5a CK	125	pr_debug("setting frequency for cpu %d to %d kHz, " \
1e21fd5a CK	126	"1/%d of max frequency\n",
36ca4ba4 CK	127	policy->cpu,
36ca4ba4 CK	128	cbe_freqs[cbe_pmode_new].frequency,
50701588	129	cbe_freqs[cbe_pmode_new].driver_data);
36ca4ba4	130
d4019f0a	131	return set_pmode(policy->cpu, cbe_pmode_new);
36ca4ba4 CK	132	}
	133
	134	static struct cpufreq_driver cbe_cpufreq_driver = {
c3bc3d67	135	.verify = cpufreq_generic_frequency_table_verify,
9c0ebcf7	136	.target_index = cbe_cpufreq_target,
36ca4ba4	137	.init = cbe_cpufreq_cpu_init,
afe96907	138	.exit = cbe_cpufreq_cpu_exit,
36ca4ba4	139	.name = "cbe-cpufreq",
36ca4ba4 CK	140	.flags = CPUFREQ_CONST_LOOPS,
	141	};
	142
	143	/*
	144	* module init and destoy
	145	*/
	146
	147	static int __init cbe_cpufreq_init(void)
	148	{
afe96907 VK	149	int ret;
afe96907 VK	150
4bd4aa19 OJ	151	if (!machine_is(cell))
4bd4aa19 OJ	152	return -ENODEV;
5050063c	153
afe96907 VK	154	cbe_cpufreq_pmi_init();
	155
	156	ret = cpufreq_register_driver(&cbe_cpufreq_driver);
	157	if (ret)
	158	cbe_cpufreq_pmi_exit();
	159
	160	return ret;
36ca4ba4 CK	161	}
	162
	163	static void __exit cbe_cpufreq_exit(void)
	164	{
	165	cpufreq_unregister_driver(&cbe_cpufreq_driver);
afe96907	166	cbe_cpufreq_pmi_exit();
36ca4ba4 CK	167	}
	168
	169	module_init(cbe_cpufreq_init);
	170	module_exit(cbe_cpufreq_exit);
	171
	172	MODULE_LICENSE("GPL");
	173	MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");