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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> |
26 | ||
4bd4aa19 | 27 | #include <asm/machdep.h> |
74889e41 | 28 | #include <asm/prom.h> |
eef686a0 | 29 | #include <asm/cell-regs.h> |
6eb1c377 VK |
30 | |
31 | #include "ppc_cbe_cpufreq.h" | |
36ca4ba4 CK |
32 | |
33 | static DEFINE_MUTEX(cbe_switch_mutex); | |
34 | ||
35 | ||
36 | /* the CBE supports an 8 step frequency scaling */ | |
37 | static struct cpufreq_frequency_table cbe_freqs[] = { | |
38 | {1, 0}, | |
39 | {2, 0}, | |
40 | {3, 0}, | |
41 | {4, 0}, | |
42 | {5, 0}, | |
43 | {6, 0}, | |
44 | {8, 0}, | |
45 | {10, 0}, | |
46 | {0, CPUFREQ_TABLE_END}, | |
47 | }; | |
48 | ||
36ca4ba4 CK |
49 | /* |
50 | * hardware specific functions | |
51 | */ | |
52 | ||
74889e41 | 53 | static int set_pmode(unsigned int cpu, unsigned int slow_mode) |
813f9072 | 54 | { |
1e21fd5a | 55 | int rc; |
74889e41 | 56 | |
813f9072 | 57 | if (cbe_cpufreq_has_pmi) |
74889e41 | 58 | rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode); |
1e21fd5a | 59 | else |
74889e41 | 60 | rc = cbe_cpufreq_set_pmode(cpu, slow_mode); |
1e21fd5a | 61 | |
74889e41 | 62 | pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu)); |
1e21fd5a CK |
63 | |
64 | return rc; | |
5050063c CK |
65 | } |
66 | ||
36ca4ba4 CK |
67 | /* |
68 | * cpufreq functions | |
69 | */ | |
70 | ||
4bd4aa19 | 71 | static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy) |
36ca4ba4 | 72 | { |
9c1a2bae SR |
73 | const u32 *max_freqp; |
74 | u32 max_freq; | |
36ca4ba4 CK |
75 | int i, cur_pmode; |
76 | struct device_node *cpu; | |
77 | ||
78 | cpu = of_get_cpu_node(policy->cpu, NULL); | |
79 | ||
4bd4aa19 | 80 | if (!cpu) |
36ca4ba4 CK |
81 | return -ENODEV; |
82 | ||
83 | pr_debug("init cpufreq on CPU %d\n", policy->cpu); | |
84 | ||
64bafa9d JCD |
85 | /* |
86 | * Let's check we can actually get to the CELL regs | |
87 | */ | |
88 | if (!cbe_get_cpu_pmd_regs(policy->cpu) || | |
89 | !cbe_get_cpu_mic_tm_regs(policy->cpu)) { | |
90 | pr_info("invalid CBE regs pointers for cpufreq\n"); | |
91 | return -EINVAL; | |
92 | } | |
93 | ||
9c1a2bae | 94 | max_freqp = of_get_property(cpu, "clock-frequency", NULL); |
36ca4ba4 | 95 | |
1e21fd5a CK |
96 | of_node_put(cpu); |
97 | ||
9c1a2bae | 98 | if (!max_freqp) |
36ca4ba4 CK |
99 | return -EINVAL; |
100 | ||
4bd4aa19 | 101 | /* we need the freq in kHz */ |
9c1a2bae | 102 | max_freq = *max_freqp / 1000; |
36ca4ba4 | 103 | |
9c1a2bae | 104 | pr_debug("max clock-frequency is at %u kHz\n", max_freq); |
36ca4ba4 CK |
105 | pr_debug("initializing frequency table\n"); |
106 | ||
4bd4aa19 | 107 | /* initialize frequency table */ |
36ca4ba4 | 108 | for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) { |
50701588 | 109 | cbe_freqs[i].frequency = max_freq / cbe_freqs[i].driver_data; |
36ca4ba4 CK |
110 | pr_debug("%d: %d\n", i, cbe_freqs[i].frequency); |
111 | } | |
112 | ||
1e21fd5a CK |
113 | /* if DEBUG is enabled set_pmode() measures the latency |
114 | * of a transition */ | |
36ca4ba4 CK |
115 | policy->cpuinfo.transition_latency = 25000; |
116 | ||
74889e41 | 117 | cur_pmode = cbe_cpufreq_get_pmode(policy->cpu); |
36ca4ba4 CK |
118 | pr_debug("current pmode is at %d\n",cur_pmode); |
119 | ||
120 | policy->cur = cbe_freqs[cur_pmode].frequency; | |
121 | ||
122 | #ifdef CONFIG_SMP | |
cc1ba8ea | 123 | cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu)); |
36ca4ba4 CK |
124 | #endif |
125 | ||
1e21fd5a CK |
126 | /* this ensures that policy->cpuinfo_min |
127 | * and policy->cpuinfo_max are set correctly */ | |
6b4147db | 128 | return cpufreq_table_validate_and_show(policy, cbe_freqs); |
36ca4ba4 CK |
129 | } |
130 | ||
1e21fd5a | 131 | static int cbe_cpufreq_target(struct cpufreq_policy *policy, |
9c0ebcf7 | 132 | unsigned int cbe_pmode_new) |
36ca4ba4 CK |
133 | { |
134 | int rc; | |
135 | struct cpufreq_freqs freqs; | |
36ca4ba4 CK |
136 | |
137 | freqs.old = policy->cur; | |
138 | freqs.new = cbe_freqs[cbe_pmode_new].frequency; | |
36ca4ba4 | 139 | |
4bd4aa19 | 140 | mutex_lock(&cbe_switch_mutex); |
b43a7ffb | 141 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
36ca4ba4 | 142 | |
1e21fd5a CK |
143 | pr_debug("setting frequency for cpu %d to %d kHz, " \ |
144 | "1/%d of max frequency\n", | |
36ca4ba4 CK |
145 | policy->cpu, |
146 | cbe_freqs[cbe_pmode_new].frequency, | |
50701588 | 147 | cbe_freqs[cbe_pmode_new].driver_data); |
36ca4ba4 CK |
148 | |
149 | rc = set_pmode(policy->cpu, cbe_pmode_new); | |
1e21fd5a | 150 | |
b43a7ffb | 151 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
36ca4ba4 CK |
152 | mutex_unlock(&cbe_switch_mutex); |
153 | ||
154 | return rc; | |
155 | } | |
156 | ||
157 | static struct cpufreq_driver cbe_cpufreq_driver = { | |
c3bc3d67 | 158 | .verify = cpufreq_generic_frequency_table_verify, |
9c0ebcf7 | 159 | .target_index = cbe_cpufreq_target, |
36ca4ba4 | 160 | .init = cbe_cpufreq_cpu_init, |
c3bc3d67 | 161 | .exit = cpufreq_generic_exit, |
36ca4ba4 | 162 | .name = "cbe-cpufreq", |
36ca4ba4 CK |
163 | .flags = CPUFREQ_CONST_LOOPS, |
164 | }; | |
165 | ||
166 | /* | |
167 | * module init and destoy | |
168 | */ | |
169 | ||
170 | static int __init cbe_cpufreq_init(void) | |
171 | { | |
4bd4aa19 OJ |
172 | if (!machine_is(cell)) |
173 | return -ENODEV; | |
5050063c | 174 | |
36ca4ba4 CK |
175 | return cpufreq_register_driver(&cbe_cpufreq_driver); |
176 | } | |
177 | ||
178 | static void __exit cbe_cpufreq_exit(void) | |
179 | { | |
180 | cpufreq_unregister_driver(&cbe_cpufreq_driver); | |
181 | } | |
182 | ||
183 | module_init(cbe_cpufreq_init); | |
184 | module_exit(cbe_cpufreq_exit); | |
185 | ||
186 | MODULE_LICENSE("GPL"); | |
187 | MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); |