arch/x86/kernel/cpu/cpufreq/p4-clockmod.c

   1 /*
   2  *      Pentium 4/Xeon CPU on demand clock modulation/speed scaling
   3  *      (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
   4  *      (C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
   5  *      (C) 2002 Arjan van de Ven <arjanv@redhat.com>
   6  *      (C) 2002 Tora T. Engstad
   7  *      All Rights Reserved
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  *
  14  *      The author(s) of this software shall not be held liable for damages
  15  *      of any nature resulting due to the use of this software. This
  16  *      software is provided AS-IS with no warranties.
  17  *
  18  *      Date            Errata                  Description
  19  *      20020525        N44, O17        12.5% or 25% DC causes lockup
  20  *
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/init.h>
  26 #include <linux/smp.h>
  27 #include <linux/cpufreq.h>
  28 #include <linux/slab.h>
  29 #include <linux/cpumask.h>
  30
  31 #include <asm/processor.h>
  32 #include <asm/msr.h>
  33 #include <asm/timex.h>
  34
  35 #include "speedstep-lib.h"
  36
  37 #define PFX     "p4-clockmod: "
  38 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "p4-clockmod", msg)
  39
  40 /*
  41  * Duty Cycle (3bits), note DC_DISABLE is not specified in
  42  * intel docs i just use it to mean disable
  43  */
  44 enum {
  45         DC_RESV, DC_DFLT, DC_25PT, DC_38PT, DC_50PT,
  46         DC_64PT, DC_75PT, DC_88PT, DC_DISABLE
  47 };
  48
  49 #define DC_ENTRIES      8
  50
  51
  52 static int has_N44_O17_errata[NR_CPUS];
  53 static unsigned int stock_freq;
  54 static struct cpufreq_driver p4clockmod_driver;
  55 static unsigned int cpufreq_p4_get(unsigned int cpu);
  56
  57 static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
  58 {
  59         u32 l, h;
  60
  61         if (!cpu_online(cpu) || (newstate > DC_DISABLE) || (newstate == DC_RESV))
  62                 return -EINVAL;
  63
  64         rdmsr_on_cpu(cpu, MSR_IA32_THERM_STATUS, &l, &h);
  65
  66         if (l & 0x01)
  67                 dprintk("CPU#%d currently thermal throttled\n", cpu);
  68
  69         if (has_N44_O17_errata[cpu] && (newstate == DC_25PT || newstate == DC_DFLT))
  70                 newstate = DC_38PT;
  71
  72         rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
  73         if (newstate == DC_DISABLE) {
  74                 dprintk("CPU#%d disabling modulation\n", cpu);
  75                 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
  76         } else {
  77                 dprintk("CPU#%d setting duty cycle to %d%%\n",
  78                         cpu, ((125 * newstate) / 10));
  79                 /* bits 63 - 5  : reserved
  80                  * bit  4       : enable/disable
  81                  * bits 3-1     : duty cycle
  82                  * bit  0       : reserved
  83                  */
  84                 l = (l & ~14);
  85                 l = l | (1<<4) | ((newstate & 0x7)<<1);
  86                 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l, h);
  87         }
  88
  89         return 0;
  90 }
  91
  92
  93 static struct cpufreq_frequency_table p4clockmod_table[] = {
  94         {DC_RESV, CPUFREQ_ENTRY_INVALID},
  95         {DC_DFLT, 0},
  96         {DC_25PT, 0},
  97         {DC_38PT, 0},
  98         {DC_50PT, 0},
  99         {DC_64PT, 0},
 100         {DC_75PT, 0},
 101         {DC_88PT, 0},
 102         {DC_DISABLE, 0},
 103         {DC_RESV, CPUFREQ_TABLE_END},
 104 };
 105
 106
 107 static int cpufreq_p4_target(struct cpufreq_policy *policy,
 108                              unsigned int target_freq,
 109                              unsigned int relation)
 110 {
 111         unsigned int    newstate = DC_RESV;
 112         struct cpufreq_freqs freqs;
 113         int i;
 114
 115         if (cpufreq_frequency_table_target(policy, &p4clockmod_table[0], target_freq, relation, &newstate))
 116                 return -EINVAL;
 117
 118         freqs.old = cpufreq_p4_get(policy->cpu);
 119         freqs.new = stock_freq * p4clockmod_table[newstate].index / 8;
 120
 121         if (freqs.new == freqs.old)
 122                 return 0;
 123
 124         /* notifiers */
 125         for_each_cpu_mask(i, policy->cpus) {
 126                 freqs.cpu = i;
 127                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 128         }
 129
 130         /* run on each logical CPU, see section 13.15.3 of IA32 Intel Architecture Software
 131          * Developer's Manual, Volume 3
 132          */
 133         for_each_cpu_mask(i, policy->cpus)
 134                 cpufreq_p4_setdc(i, p4clockmod_table[newstate].index);
 135
 136         /* notifiers */
 137         for_each_cpu_mask(i, policy->cpus) {
 138                 freqs.cpu = i;
 139                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 140         }
 141
 142         return 0;
 143 }
 144
 145
 146 static int cpufreq_p4_verify(struct cpufreq_policy *policy)
 147 {
 148         return cpufreq_frequency_table_verify(policy, &p4clockmod_table[0]);
 149 }
 150
 151
 152 static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
 153 {
 154         if (c->x86 == 0x06) {
 155                 if (cpu_has(c, X86_FEATURE_EST))
 156                         printk(KERN_WARNING PFX "Warning: EST-capable CPU detected. "
 157                                "The acpi-cpufreq module offers voltage scaling"
 158                                " in addition of frequency scaling. You should use "
 159                                "that instead of p4-clockmod, if possible.\n");
 160                 switch (c->x86_model) {
 161                 case 0x0E: /* Core */
 162                 case 0x0F: /* Core Duo */
 163                         p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
 164                         return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_PCORE);
 165                 case 0x0D: /* Pentium M (Dothan) */
 166                         p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
 167                         /* fall through */
 168                 case 0x09: /* Pentium M (Banias) */
 169                         return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_PM);
 170                 }
 171         }
 172
 173         if (c->x86 != 0xF) {
 174                 printk(KERN_WARNING PFX "Unknown p4-clockmod-capable CPU. Please send an e-mail to <cpufreq@lists.linux.org.uk>\n");
 175                 return 0;
 176         }
 177
 178         /* on P-4s, the TSC runs with constant frequency independent whether
 179          * throttling is active or not. */
 180         p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
 181
 182         if (speedstep_detect_processor() == SPEEDSTEP_PROCESSOR_P4M) {
 183                 printk(KERN_WARNING PFX "Warning: Pentium 4-M detected. "
 184                        "The speedstep-ich or acpi cpufreq modules offer "
 185                        "voltage scaling in addition of frequency scaling. "
 186                        "You should use either one instead of p4-clockmod, "
 187                        "if possible.\n");
 188                 return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_P4M);
 189         }
 190
 191         return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_P4D);
 192 }
 193
 194
 195
 196 static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
 197 {
 198         struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
 199         int cpuid = 0;
 200         unsigned int i;
 201
 202 #ifdef CONFIG_SMP
 203         policy->cpus = per_cpu(cpu_sibling_map, policy->cpu);
 204 #endif
 205
 206         /* Errata workaround */
 207         cpuid = (c->x86 << 8) | (c->x86_model << 4) | c->x86_mask;
 208         switch (cpuid) {
 209         case 0x0f07:
 210         case 0x0f0a:
 211         case 0x0f11:
 212         case 0x0f12:
 213                 has_N44_O17_errata[policy->cpu] = 1;
 214                 dprintk("has errata -- disabling low frequencies\n");
 215         }
 216
 217         /* get max frequency */
 218         stock_freq = cpufreq_p4_get_frequency(c);
 219         if (!stock_freq)
 220                 return -EINVAL;
 221
 222         /* table init */
 223         for (i=1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {
 224                 if ((i<2) && (has_N44_O17_errata[policy->cpu]))
 225                         p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 226                 else
 227                         p4clockmod_table[i].frequency = (stock_freq * i)/8;
 228         }
 229         cpufreq_frequency_table_get_attr(p4clockmod_table, policy->cpu);
 230
 231         /* cpuinfo and default policy values */
 232         policy->cpuinfo.transition_latency = 1000000; /* assumed */
 233         policy->cur = stock_freq;
 234
 235         return cpufreq_frequency_table_cpuinfo(policy, &p4clockmod_table[0]);
 236 }
 237
 238
 239 static int cpufreq_p4_cpu_exit(struct cpufreq_policy *policy)
 240 {
 241         cpufreq_frequency_table_put_attr(policy->cpu);
 242         return 0;
 243 }
 244
 245 static unsigned int cpufreq_p4_get(unsigned int cpu)
 246 {
 247         u32 l, h;
 248
 249         rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
 250
 251         if (l & 0x10) {
 252                 l = l >> 1;
 253                 l &= 0x7;
 254         } else
 255                 l = DC_DISABLE;
 256
 257         if (l != DC_DISABLE)
 258                 return (stock_freq * l / 8);
 259
 260         return stock_freq;
 261 }
 262
 263 static struct freq_attr* p4clockmod_attr[] = {
 264         &cpufreq_freq_attr_scaling_available_freqs,
 265         NULL,
 266 };
 267
 268 static struct cpufreq_driver p4clockmod_driver = {
 269         .verify         = cpufreq_p4_verify,
 270         .target         = cpufreq_p4_target,
 271         .init           = cpufreq_p4_cpu_init,
 272         .exit           = cpufreq_p4_cpu_exit,
 273         .get            = cpufreq_p4_get,
 274         .name           = "p4-clockmod",
 275         .owner          = THIS_MODULE,
 276         .attr           = p4clockmod_attr,
 277 };
 278
 279
 280 static int __init cpufreq_p4_init(void)
 281 {
 282         struct cpuinfo_x86 *c = &cpu_data(0);
 283         int ret;
 284
 285         /*
 286          * THERM_CONTROL is architectural for IA32 now, so
 287          * we can rely on the capability checks
 288          */
 289         if (c->x86_vendor != X86_VENDOR_INTEL)
 290                 return -ENODEV;
 291
 292         if (!test_bit(X86_FEATURE_ACPI, c->x86_capability) ||
 293                 !test_bit(X86_FEATURE_ACC, c->x86_capability))
 294                 return -ENODEV;
 295
 296         ret = cpufreq_register_driver(&p4clockmod_driver);
 297         if (!ret)
 298                 printk(KERN_INFO PFX "P4/Xeon(TM) CPU On-Demand Clock Modulation available\n");
 299
 300         return (ret);
 301 }
 302
 303
 304 static void __exit cpufreq_p4_exit(void)
 305 {
 306         cpufreq_unregister_driver(&p4clockmod_driver);
 307 }
 308
 309
 310 MODULE_AUTHOR ("Zwane Mwaikambo <zwane@commfireservices.com>");
 311 MODULE_DESCRIPTION ("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
 312 MODULE_LICENSE ("GPL");
 313
 314 late_initcall(cpufreq_p4_init);
 315 module_exit(cpufreq_p4_exit);