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