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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 | /* * sc520_freq.c: cpufreq driver for the AMD Elan sc520 * * Copyright (C) 2005 Sean Young <sean@mess.org> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Based on elanfreq.c * * 2005-03-30: - initial revision */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/delay.h> #include <linux/cpufreq.h> #include <linux/timex.h> #include <linux/io.h> #include <asm/msr.h> #define MMCR_BASE 0xfffef000 /* The default base address */ #define OFFS_CPUCTL 0x2 /* CPU Control Register */ static __u8 __iomem *cpuctl; #define PFX "sc520_freq: " static struct cpufreq_frequency_table sc520_freq_table[] = { {0x01, 100000}, {0x02, 133000}, {0, CPUFREQ_TABLE_END}, }; static unsigned int sc520_freq_get_cpu_frequency(unsigned int cpu) { u8 clockspeed_reg = *cpuctl; switch (clockspeed_reg & 0x03) { default: printk(KERN_ERR PFX "error: cpuctl register has unexpected " "value %02x\n", clockspeed_reg); case 0x01: return 100000; case 0x02: return 133000; } } static void sc520_freq_set_cpu_state(unsigned int state) { struct cpufreq_freqs freqs; u8 clockspeed_reg; freqs.old = sc520_freq_get_cpu_frequency(0); freqs.new = sc520_freq_table[state].frequency; freqs.cpu = 0; /* AMD Elan is UP */ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); pr_debug("attempting to set frequency to %i kHz\n", sc520_freq_table[state].frequency); local_irq_disable(); clockspeed_reg = *cpuctl & ~0x03; *cpuctl = clockspeed_reg | sc520_freq_table[state].index; local_irq_enable(); cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); }; static int sc520_freq_verify(struct cpufreq_policy *policy) { return cpufreq_frequency_table_verify(policy, &sc520_freq_table[0]); } static int sc520_freq_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { unsigned int newstate = 0; if (cpufreq_frequency_table_target(policy, sc520_freq_table, target_freq, relation, &newstate)) return -EINVAL; sc520_freq_set_cpu_state(newstate); return 0; } /* * Module init and exit code */ static int sc520_freq_cpu_init(struct cpufreq_policy *policy) { struct cpuinfo_x86 *c = &cpu_data(0); int result; /* capability check */ if (c->x86_vendor != X86_VENDOR_AMD || c->x86 != 4 || c->x86_model != 9) return -ENODEV; /* cpuinfo and default policy values */ policy->cpuinfo.transition_latency = 1000000; /* 1ms */ policy->cur = sc520_freq_get_cpu_frequency(0); result = cpufreq_frequency_table_cpuinfo(policy, sc520_freq_table); if (result) return result; cpufreq_frequency_table_get_attr(sc520_freq_table, policy->cpu); return 0; } static int sc520_freq_cpu_exit(struct cpufreq_policy *policy) { cpufreq_frequency_table_put_attr(policy->cpu); return 0; } static struct freq_attr *sc520_freq_attr[] = { &cpufreq_freq_attr_scaling_available_freqs, NULL, }; static struct cpufreq_driver sc520_freq_driver = { .get = sc520_freq_get_cpu_frequency, .verify = sc520_freq_verify, .target = sc520_freq_target, .init = sc520_freq_cpu_init, .exit = sc520_freq_cpu_exit, .name = "sc520_freq", .owner = THIS_MODULE, .attr = sc520_freq_attr, }; static int __init sc520_freq_init(void) { struct cpuinfo_x86 *c = &cpu_data(0); int err; /* Test if we have the right hardware */ if (c->x86_vendor != X86_VENDOR_AMD || c->x86 != 4 || c->x86_model != 9) { pr_debug("no Elan SC520 processor found!\n"); return -ENODEV; } cpuctl = ioremap((unsigned long)(MMCR_BASE + OFFS_CPUCTL), 1); if (!cpuctl) { printk(KERN_ERR "sc520_freq: error: failed to remap memory\n"); return -ENOMEM; } err = cpufreq_register_driver(&sc520_freq_driver); if (err) iounmap(cpuctl); return err; } static void __exit sc520_freq_exit(void) { cpufreq_unregister_driver(&sc520_freq_driver); iounmap(cpuctl); } MODULE_LICENSE("GPL"); MODULE_AUTHOR("Sean Young <sean@mess.org>"); MODULE_DESCRIPTION("cpufreq driver for AMD's Elan sc520 CPU"); module_init(sc520_freq_init); module_exit(sc520_freq_exit); |