projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 64909882 G |
1 | /* |
| 2 | * linux/arch/unicore32/kernel/cpu-ucv2.c: clock scaling for the UniCore-II | |
| 3 | * | |
| 4 | * Code specific to PKUnity SoC and UniCore ISA | |
| 5 | * | |
| 6 | * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn> | |
| 7 | * Copyright (C) 2001-2010 Guan Xuetao | |
| 8 | * | |
| 9 | * This program is free software; you can redistribute it and/or modify | |
| 10 | * it under the terms of the GNU General Public License version 2 as | |
| 11 | * published by the Free Software Foundation. | |
| 12 | */ | |
| 13 | ||
| 14 | #include <linux/kernel.h> | |
| 15 | #include <linux/types.h> | |
| 16 | #include <linux/init.h> | |
| 17 | #include <linux/clk.h> | |
| 18 | #include <linux/cpufreq.h> | |
| 19 | ||
| 20 | #include <mach/hardware.h> | |
| 21 | ||
| 22 | static struct cpufreq_driver ucv2_driver; | |
| 23 | ||
| 24 | /* make sure that only the "userspace" governor is run | |
| 25 | * -- anything else wouldn't make sense on this platform, anyway. | |
| 26 | */ | |
| 27 | int ucv2_verify_speed(struct cpufreq_policy *policy) | |
| 28 | { | |
| 29 | if (policy->cpu) | |
| 30 | return -EINVAL; | |
| 31 | ||
| 32 | cpufreq_verify_within_limits(policy, | |
| 33 | policy->cpuinfo.min_freq, policy->cpuinfo.max_freq); | |
| 34 | ||
| 35 | return 0; | |
| 36 | } | |
| 37 | ||
| 38 | static unsigned int ucv2_getspeed(unsigned int cpu) | |
| 39 | { | |
| 40 | struct clk *mclk = clk_get(NULL, "MAIN_CLK"); | |
| 41 | ||
| 42 | if (cpu) | |
| 43 | return 0; | |
| 44 | return clk_get_rate(mclk)/1000; | |
| 45 | } | |
| 46 | ||
| 47 | static int ucv2_target(struct cpufreq_policy *policy, | |
| 48 | unsigned int target_freq, | |
| 49 | unsigned int relation) | |
| 50 | { | |
| 51 | unsigned int cur = ucv2_getspeed(0); | |
| 52 | struct cpufreq_freqs freqs; | |
| 53 | struct clk *mclk = clk_get(NULL, "MAIN_CLK"); | |
| 54 | ||
| 55 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
| 56 | ||
| 57 | if (!clk_set_rate(mclk, target_freq * 1000)) { | |
| 58 | freqs.old = cur; | |
| 59 | freqs.new = target_freq; | |
| 60 | freqs.cpu = 0; | |
| 61 | } | |
| 62 | ||
| 63 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); | |
| 64 | ||
| 65 | return 0; | |
| 66 | } | |
| 67 | ||
| 68 | static int __init ucv2_cpu_init(struct cpufreq_policy *policy) | |
| 69 | { | |
| 70 | if (policy->cpu != 0) | |
| 71 | return -EINVAL; | |
| 72 | policy->cur = ucv2_getspeed(0); | |
| 73 | policy->min = policy->cpuinfo.min_freq = 250000; | |
| 74 | policy->max = policy->cpuinfo.max_freq = 1000000; | |
| 75 | policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; | |
| 76 | return 0; | |
| 77 | } | |
| 78 | ||
| 79 | static struct cpufreq_driver ucv2_driver = { | |
| 80 | .flags = CPUFREQ_STICKY, | |
| 81 | .verify = ucv2_verify_speed, | |
| 82 | .target = ucv2_target, | |
| 83 | .get = ucv2_getspeed, | |
| 84 | .init = ucv2_cpu_init, | |
| 85 | .name = "UniCore-II", | |
| 86 | }; | |
| 87 | ||
| 88 | static int __init ucv2_cpufreq_init(void) | |
| 89 | { | |
| 90 | return cpufreq_register_driver(&ucv2_driver); | |
| 91 | } | |
| 92 | ||
| 93 | arch_initcall(ucv2_cpufreq_init); |