| GuanXuetao | 6490988 | 2011-02-26 20:23:59 +0800 | [diff] [blame] | 1 | /* |
| Viresh Kumar | 73cc9c8 | 2013-04-04 12:54:23 +0000 | [diff] [blame] | 2 | * clock scaling for the UniCore-II |
| GuanXuetao | 6490988 | 2011-02-26 20:23:59 +0800 | [diff] [blame] | 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 | |
| Viresh Kumar | b43a7ff | 2013-03-24 11:56:43 +0530 | [diff] [blame] | 55 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
| GuanXuetao | 6490988 | 2011-02-26 20:23:59 +0800 | [diff] [blame] | 56 | |
| 57 | if (!clk_set_rate(mclk, target_freq * 1000)) { |
| 58 | freqs.old = cur; |
| 59 | freqs.new = target_freq; |
| GuanXuetao | 6490988 | 2011-02-26 20:23:59 +0800 | [diff] [blame] | 60 | } |
| 61 | |
| Viresh Kumar | b43a7ff | 2013-03-24 11:56:43 +0530 | [diff] [blame] | 62 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
| GuanXuetao | 6490988 | 2011-02-26 20:23:59 +0800 | [diff] [blame] | 63 | |
| 64 | return 0; |
| 65 | } |
| 66 | |
| 67 | static int __init ucv2_cpu_init(struct cpufreq_policy *policy) |
| 68 | { |
| 69 | if (policy->cpu != 0) |
| 70 | return -EINVAL; |
| 71 | policy->cur = ucv2_getspeed(0); |
| 72 | policy->min = policy->cpuinfo.min_freq = 250000; |
| 73 | policy->max = policy->cpuinfo.max_freq = 1000000; |
| 74 | policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; |
| 75 | return 0; |
| 76 | } |
| 77 | |
| 78 | static struct cpufreq_driver ucv2_driver = { |
| 79 | .flags = CPUFREQ_STICKY, |
| 80 | .verify = ucv2_verify_speed, |
| 81 | .target = ucv2_target, |
| 82 | .get = ucv2_getspeed, |
| 83 | .init = ucv2_cpu_init, |
| 84 | .name = "UniCore-II", |
| 85 | }; |
| 86 | |
| 87 | static int __init ucv2_cpufreq_init(void) |
| 88 | { |
| 89 | return cpufreq_register_driver(&ucv2_driver); |
| 90 | } |
| 91 | |
| 92 | arch_initcall(ucv2_cpufreq_init); |