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