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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * This file was based upon code in Powertweak Linux (http://powertweak.sf.net)4 * (C) 2000-2003 Dave Jones, Arjan van de Ven, Janne Pänkälä,5 * Dominik Brodowski.6 *7 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*8 */9 10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt11 12#include <linux/kernel.h>13#include <linux/module.h>14#include <linux/init.h>15#include <linux/cpufreq.h>16#include <linux/ioport.h>17#include <linux/timex.h>18#include <linux/io.h>19 20#include <asm/cpu_device_id.h>21#include <asm/msr.h>22 23#define POWERNOW_IOPORT 0xfff0 /* it doesn't matter where, as long24 as it is unused */25 26static unsigned int busfreq; /* FSB, in 10 kHz */27static unsigned int max_multiplier;28 29static unsigned int param_busfreq = 0;30static unsigned int param_max_multiplier = 0;31 32module_param_named(max_multiplier, param_max_multiplier, uint, S_IRUGO);33MODULE_PARM_DESC(max_multiplier, "Maximum multiplier (allowed values: 20 30 35 40 45 50 55 60)");34 35module_param_named(bus_frequency, param_busfreq, uint, S_IRUGO);36MODULE_PARM_DESC(bus_frequency, "Bus frequency in kHz");37 38/* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */39static struct cpufreq_frequency_table clock_ratio[] = {40 {0, 60, /* 110 -> 6.0x */ 0},41 {0, 55, /* 011 -> 5.5x */ 0},42 {0, 50, /* 001 -> 5.0x */ 0},43 {0, 45, /* 000 -> 4.5x */ 0},44 {0, 40, /* 010 -> 4.0x */ 0},45 {0, 35, /* 111 -> 3.5x */ 0},46 {0, 30, /* 101 -> 3.0x */ 0},47 {0, 20, /* 100 -> 2.0x */ 0},48 {0, 0, CPUFREQ_TABLE_END}49};50 51static const u8 index_to_register[8] = { 6, 3, 1, 0, 2, 7, 5, 4 };52static const u8 register_to_index[8] = { 3, 2, 4, 1, 7, 6, 0, 5 };53 54static const struct {55 unsigned freq;56 unsigned mult;57} usual_frequency_table[] = {58 { 350000, 35 }, // 100 * 3.559 { 400000, 40 }, // 100 * 460 { 450000, 45 }, // 100 * 4.561 { 475000, 50 }, // 95 * 562 { 500000, 50 }, // 100 * 563 { 506250, 45 }, // 112.5 * 4.564 { 533500, 55 }, // 97 * 5.565 { 550000, 55 }, // 100 * 5.566 { 562500, 50 }, // 112.5 * 567 { 570000, 60 }, // 95 * 668 { 600000, 60 }, // 100 * 669 { 618750, 55 }, // 112.5 * 5.570 { 660000, 55 }, // 120 * 5.571 { 675000, 60 }, // 112.5 * 672 { 720000, 60 }, // 120 * 673};74 75#define FREQ_RANGE 300076 77/**78 * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier79 *80 * Returns the current setting of the frequency multiplier. Core clock81 * speed is frequency of the Front-Side Bus multiplied with this value.82 */83static int powernow_k6_get_cpu_multiplier(void)84{85 unsigned long invalue = 0;86 u32 msrval;87 88 local_irq_disable();89 90 msrval = POWERNOW_IOPORT + 0x1;91 wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */92 invalue = inl(POWERNOW_IOPORT + 0x8);93 msrval = POWERNOW_IOPORT + 0x0;94 wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */95 96 local_irq_enable();97 98 return clock_ratio[register_to_index[(invalue >> 5)&7]].driver_data;99}100 101static void powernow_k6_set_cpu_multiplier(unsigned int best_i)102{103 unsigned long outvalue, invalue;104 unsigned long msrval;105 unsigned long cr0;106 107 /* we now need to transform best_i to the BVC format, see AMD#23446 */108 109 /*110 * The processor doesn't respond to inquiry cycles while changing the111 * frequency, so we must disable cache.112 */113 local_irq_disable();114 cr0 = read_cr0();115 write_cr0(cr0 | X86_CR0_CD);116 wbinvd();117 118 outvalue = (1<<12) | (1<<10) | (1<<9) | (index_to_register[best_i]<<5);119 120 msrval = POWERNOW_IOPORT + 0x1;121 wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */122 invalue = inl(POWERNOW_IOPORT + 0x8);123 invalue = invalue & 0x1f;124 outvalue = outvalue | invalue;125 outl(outvalue, (POWERNOW_IOPORT + 0x8));126 msrval = POWERNOW_IOPORT + 0x0;127 wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */128 129 write_cr0(cr0);130 local_irq_enable();131}132 133/**134 * powernow_k6_target - set the PowerNow! multiplier135 * @best_i: clock_ratio[best_i] is the target multiplier136 *137 * Tries to change the PowerNow! multiplier138 */139static int powernow_k6_target(struct cpufreq_policy *policy,140 unsigned int best_i)141{142 143 if (clock_ratio[best_i].driver_data > max_multiplier) {144 pr_err("invalid target frequency\n");145 return -EINVAL;146 }147 148 powernow_k6_set_cpu_multiplier(best_i);149 150 return 0;151}152 153static int powernow_k6_cpu_init(struct cpufreq_policy *policy)154{155 struct cpufreq_frequency_table *pos;156 unsigned int i, f;157 unsigned khz;158 159 if (policy->cpu != 0)160 return -ENODEV;161 162 max_multiplier = 0;163 khz = cpu_khz;164 for (i = 0; i < ARRAY_SIZE(usual_frequency_table); i++) {165 if (khz >= usual_frequency_table[i].freq - FREQ_RANGE &&166 khz <= usual_frequency_table[i].freq + FREQ_RANGE) {167 khz = usual_frequency_table[i].freq;168 max_multiplier = usual_frequency_table[i].mult;169 break;170 }171 }172 if (param_max_multiplier) {173 cpufreq_for_each_entry(pos, clock_ratio)174 if (pos->driver_data == param_max_multiplier) {175 max_multiplier = param_max_multiplier;176 goto have_max_multiplier;177 }178 pr_err("invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n");179 return -EINVAL;180 }181 182 if (!max_multiplier) {183 pr_warn("unknown frequency %u, cannot determine current multiplier\n",184 khz);185 pr_warn("use module parameters max_multiplier and bus_frequency\n");186 return -EOPNOTSUPP;187 }188 189have_max_multiplier:190 param_max_multiplier = max_multiplier;191 192 if (param_busfreq) {193 if (param_busfreq >= 50000 && param_busfreq <= 150000) {194 busfreq = param_busfreq / 10;195 goto have_busfreq;196 }197 pr_err("invalid bus_frequency parameter, allowed range 50000 - 150000 kHz\n");198 return -EINVAL;199 }200 201 busfreq = khz / max_multiplier;202have_busfreq:203 param_busfreq = busfreq * 10;204 205 /* table init */206 cpufreq_for_each_entry(pos, clock_ratio) {207 f = pos->driver_data;208 if (f > max_multiplier)209 pos->frequency = CPUFREQ_ENTRY_INVALID;210 else211 pos->frequency = busfreq * f;212 }213 214 /* cpuinfo and default policy values */215 policy->cpuinfo.transition_latency = 500000;216 policy->freq_table = clock_ratio;217 218 return 0;219}220 221 222static void powernow_k6_cpu_exit(struct cpufreq_policy *policy)223{224 unsigned int i;225 226 for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {227 if (clock_ratio[i].driver_data == max_multiplier) {228 struct cpufreq_freqs freqs;229 230 freqs.old = policy->cur;231 freqs.new = clock_ratio[i].frequency;232 freqs.flags = 0;233 234 cpufreq_freq_transition_begin(policy, &freqs);235 powernow_k6_target(policy, i);236 cpufreq_freq_transition_end(policy, &freqs, 0);237 return;238 }239 }240}241 242static unsigned int powernow_k6_get(unsigned int cpu)243{244 unsigned int ret;245 ret = (busfreq * powernow_k6_get_cpu_multiplier());246 return ret;247}248 249static struct cpufreq_driver powernow_k6_driver = {250 .verify = cpufreq_generic_frequency_table_verify,251 .target_index = powernow_k6_target,252 .init = powernow_k6_cpu_init,253 .exit = powernow_k6_cpu_exit,254 .get = powernow_k6_get,255 .name = "powernow-k6",256 .attr = cpufreq_generic_attr,257};258 259static const struct x86_cpu_id powernow_k6_ids[] = {260 X86_MATCH_VENDOR_FAM_MODEL(AMD, 5, 12, NULL),261 X86_MATCH_VENDOR_FAM_MODEL(AMD, 5, 13, NULL),262 {}263};264MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids);265 266/**267 * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver268 *269 * Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported270 * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero271 * on success.272 */273static int __init powernow_k6_init(void)274{275 if (!x86_match_cpu(powernow_k6_ids))276 return -ENODEV;277 278 if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {279 pr_info("PowerNow IOPORT region already used\n");280 return -EIO;281 }282 283 if (cpufreq_register_driver(&powernow_k6_driver)) {284 release_region(POWERNOW_IOPORT, 16);285 return -EINVAL;286 }287 288 return 0;289}290 291 292/**293 * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support294 *295 * Unregisters AMD K6-2+ / K6-3+ PowerNow! support.296 */297static void __exit powernow_k6_exit(void)298{299 cpufreq_unregister_driver(&powernow_k6_driver);300 release_region(POWERNOW_IOPORT, 16);301}302 303 304MODULE_AUTHOR("Arjan van de Ven, Dave Jones, "305 "Dominik Brodowski <linux@brodo.de>");306MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");307MODULE_LICENSE("GPL");308 309module_init(powernow_k6_init);310module_exit(powernow_k6_exit);311