1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * clock scaling for the UniCore-II
4 *
5 * Code specific to PKUnity SoC and UniCore ISA
6 *
7 * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
8 * Copyright (C) 2001-2010 Guan Xuetao
9 */
10
11 #include <linux/err.h>
12 #include <linux/kernel.h>
13 #include <linux/types.h>
14 #include <linux/init.h>
15 #include <linux/clk.h>
16 #include <linux/cpufreq.h>
17
18 #include <mach/hardware.h>
19
20 static struct cpufreq_driver ucv2_driver;
21
22 /* make sure that only the "userspace" governor is run
23 * -- anything else wouldn't make sense on this platform, anyway.
24 */
ucv2_verify_speed(struct cpufreq_policy_data * policy)25 static int ucv2_verify_speed(struct cpufreq_policy_data *policy)
26 {
27 if (policy->cpu)
28 return -EINVAL;
29
30 cpufreq_verify_within_cpu_limits(policy);
31 return 0;
32 }
33
ucv2_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)34 static int ucv2_target(struct cpufreq_policy *policy,
35 unsigned int target_freq,
36 unsigned int relation)
37 {
38 struct cpufreq_freqs freqs;
39 int ret;
40
41 freqs.old = policy->cur;
42 freqs.new = target_freq;
43
44 cpufreq_freq_transition_begin(policy, &freqs);
45 ret = clk_set_rate(policy->clk, target_freq * 1000);
46 cpufreq_freq_transition_end(policy, &freqs, ret);
47
48 return ret;
49 }
50
ucv2_cpu_init(struct cpufreq_policy * policy)51 static int __init ucv2_cpu_init(struct cpufreq_policy *policy)
52 {
53 if (policy->cpu != 0)
54 return -EINVAL;
55
56 policy->min = policy->cpuinfo.min_freq = 250000;
57 policy->max = policy->cpuinfo.max_freq = 1000000;
58 policy->clk = clk_get(NULL, "MAIN_CLK");
59 return PTR_ERR_OR_ZERO(policy->clk);
60 }
61
62 static struct cpufreq_driver ucv2_driver = {
63 .flags = CPUFREQ_STICKY | CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
64 .verify = ucv2_verify_speed,
65 .target = ucv2_target,
66 .get = cpufreq_generic_get,
67 .init = ucv2_cpu_init,
68 .name = "UniCore-II",
69 };
70
ucv2_cpufreq_init(void)71 static int __init ucv2_cpufreq_init(void)
72 {
73 return cpufreq_register_driver(&ucv2_driver);
74 }
75
76 arch_initcall(ucv2_cpufreq_init);
77