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 */ |
20 | static 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 | |
36 | static 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, pmode: slow_mode); |
42 | else |
43 | rc = cbe_cpufreq_set_pmode(cpu, pmode: 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 | |
54 | static 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(cpu: 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(node: cpu); |
76 | return -EINVAL; |
77 | } |
78 | |
79 | max_freqp = of_get_property(node: cpu, name: "clock-frequency" , NULL); |
80 | |
81 | of_node_put(node: 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(cpu: 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(dstp: policy->cpus, srcp: 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 | |
116 | static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy) |
117 | { |
118 | cbe_cpufreq_pmi_policy_exit(policy); |
119 | return 0; |
120 | } |
121 | |
122 | static int cbe_cpufreq_target(struct cpufreq_policy *policy, |
123 | unsigned int cbe_pmode_new) |
124 | { |
125 | pr_debug("setting frequency for cpu %d to %d kHz, " \ |
126 | "1/%d of max frequency\n" , |
127 | policy->cpu, |
128 | cbe_freqs[cbe_pmode_new].frequency, |
129 | cbe_freqs[cbe_pmode_new].driver_data); |
130 | |
131 | return set_pmode(cpu: policy->cpu, slow_mode: cbe_pmode_new); |
132 | } |
133 | |
134 | static struct cpufreq_driver cbe_cpufreq_driver = { |
135 | .verify = cpufreq_generic_frequency_table_verify, |
136 | .target_index = cbe_cpufreq_target, |
137 | .init = cbe_cpufreq_cpu_init, |
138 | .exit = cbe_cpufreq_cpu_exit, |
139 | .name = "cbe-cpufreq" , |
140 | .flags = CPUFREQ_CONST_LOOPS, |
141 | }; |
142 | |
143 | /* |
144 | * module init and destoy |
145 | */ |
146 | |
147 | static int __init cbe_cpufreq_init(void) |
148 | { |
149 | int ret; |
150 | |
151 | if (!machine_is(cell)) |
152 | return -ENODEV; |
153 | |
154 | cbe_cpufreq_pmi_init(); |
155 | |
156 | ret = cpufreq_register_driver(driver_data: &cbe_cpufreq_driver); |
157 | if (ret) |
158 | cbe_cpufreq_pmi_exit(); |
159 | |
160 | return ret; |
161 | } |
162 | |
163 | static void __exit cbe_cpufreq_exit(void) |
164 | { |
165 | cpufreq_unregister_driver(driver_data: &cbe_cpufreq_driver); |
166 | cbe_cpufreq_pmi_exit(); |
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>" ); |
174 | |