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80 lines
1.9 KiB
80 lines
1.9 KiB
/* |
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* clock scaling for the UniCore-II |
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* |
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* Code specific to PKUnity SoC and UniCore ISA |
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* |
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* Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn> |
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* Copyright (C) 2001-2010 Guan Xuetao |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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*/ |
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#include <linux/err.h> |
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#include <linux/kernel.h> |
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#include <linux/types.h> |
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#include <linux/init.h> |
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#include <linux/clk.h> |
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#include <linux/cpufreq.h> |
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#include <mach/hardware.h> |
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static struct cpufreq_driver ucv2_driver; |
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/* make sure that only the "userspace" governor is run |
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* -- anything else wouldn't make sense on this platform, anyway. |
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*/ |
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static int ucv2_verify_speed(struct cpufreq_policy *policy) |
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{ |
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if (policy->cpu) |
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return -EINVAL; |
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cpufreq_verify_within_cpu_limits(policy); |
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return 0; |
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} |
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static int ucv2_target(struct cpufreq_policy *policy, |
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unsigned int target_freq, |
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unsigned int relation) |
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{ |
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struct cpufreq_freqs freqs; |
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int ret; |
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freqs.old = policy->cur; |
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freqs.new = target_freq; |
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cpufreq_freq_transition_begin(policy, &freqs); |
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ret = clk_set_rate(policy->clk, target_freq * 1000); |
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cpufreq_freq_transition_end(policy, &freqs, ret); |
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return ret; |
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} |
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static int __init ucv2_cpu_init(struct cpufreq_policy *policy) |
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{ |
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if (policy->cpu != 0) |
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return -EINVAL; |
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policy->min = policy->cpuinfo.min_freq = 250000; |
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policy->max = policy->cpuinfo.max_freq = 1000000; |
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policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; |
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policy->clk = clk_get(NULL, "MAIN_CLK"); |
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return PTR_ERR_OR_ZERO(policy->clk); |
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} |
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static struct cpufreq_driver ucv2_driver = { |
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.flags = CPUFREQ_STICKY, |
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.verify = ucv2_verify_speed, |
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.target = ucv2_target, |
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.get = cpufreq_generic_get, |
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.init = ucv2_cpu_init, |
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.name = "UniCore-II", |
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}; |
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static int __init ucv2_cpufreq_init(void) |
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{ |
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return cpufreq_register_driver(&ucv2_driver); |
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} |
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arch_initcall(ucv2_cpufreq_init);
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