arch/x86/kernel/cpu/cpufreq/e_powersaver.c

   1 /*
   2  *  Based on documentation provided by Dave Jones. Thanks!
   3  *
   4  *  Licensed under the terms of the GNU GPL License version 2.
   5  *
   6  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/cpufreq.h>
  13 #include <linux/ioport.h>
  14 #include <linux/slab.h>
  15
  16 #include <asm/msr.h>
  17 #include <asm/tsc.h>
  18 #include <asm/timex.h>
  19 #include <asm/io.h>
  20 #include <asm/delay.h>
  21
  22 #define EPS_BRAND_C7M   0
  23 #define EPS_BRAND_C7    1
  24 #define EPS_BRAND_EDEN  2
  25 #define EPS_BRAND_C3    3
  26 #define EPS_BRAND_C7D   4
  27
  28 struct eps_cpu_data {
  29         u32 fsb;
  30         struct cpufreq_frequency_table freq_table[];
  31 };
  32
  33 static struct eps_cpu_data *eps_cpu[NR_CPUS];
  34
  35
  36 static unsigned int eps_get(unsigned int cpu)
  37 {
  38         struct eps_cpu_data *centaur;
  39         u32 lo, hi;
  40
  41         if (cpu)
  42                 return 0;
  43         centaur = eps_cpu[cpu];
  44         if (centaur == NULL)
  45                 return 0;
  46
  47         /* Return current frequency */
  48         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
  49         return centaur->fsb * ((lo >> 8) & 0xff);
  50 }
  51
  52 static int eps_set_state(struct eps_cpu_data *centaur,
  53                          unsigned int cpu,
  54                          u32 dest_state)
  55 {
  56         struct cpufreq_freqs freqs;
  57         u32 lo, hi;
  58 <<<<<<< HEAD:arch/x86/kernel/cpu/cpufreq/e_powersaver.c
  59         u8 current_multiplier, current_voltage;
  60 =======
  61 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/x86/kernel/cpu/cpufreq/e_powersaver.c
  62         int err = 0;
  63         int i;
  64
  65         freqs.old = eps_get(cpu);
  66         freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
  67         freqs.cpu = cpu;
  68         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
  69
  70         /* Wait while CPU is busy */
  71         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
  72         i = 0;
  73         while (lo & ((1 << 16) | (1 << 17))) {
  74                 udelay(16);
  75                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
  76                 i++;
  77                 if (unlikely(i > 64)) {
  78                         err = -ENODEV;
  79                         goto postchange;
  80                 }
  81         }
  82         /* Set new multiplier and voltage */
  83         wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
  84         /* Wait until transition end */
  85         i = 0;
  86         do {
  87                 udelay(16);
  88                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
  89                 i++;
  90                 if (unlikely(i > 64)) {
  91                         err = -ENODEV;
  92                         goto postchange;
  93                 }
  94         } while (lo & ((1 << 16) | (1 << 17)));
  95
  96         /* Return current frequency */
  97 postchange:
  98         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
  99         freqs.new = centaur->fsb * ((lo >> 8) & 0xff);
 100
 101 <<<<<<< HEAD:arch/x86/kernel/cpu/cpufreq/e_powersaver.c
 102 =======
 103 #ifdef DEBUG
 104         {
 105         u8 current_multiplier, current_voltage;
 106
 107 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/x86/kernel/cpu/cpufreq/e_powersaver.c
 108         /* Print voltage and multiplier */
 109         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 110         current_voltage = lo & 0xff;
 111         printk(KERN_INFO "eps: Current voltage = %dmV\n",
 112                 current_voltage * 16 + 700);
 113         current_multiplier = (lo >> 8) & 0xff;
 114         printk(KERN_INFO "eps: Current multiplier = %d\n",
 115                 current_multiplier);
 116 <<<<<<< HEAD:arch/x86/kernel/cpu/cpufreq/e_powersaver.c
 117
 118 =======
 119         }
 120 #endif
 121 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/x86/kernel/cpu/cpufreq/e_powersaver.c
 122         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 123         return err;
 124 }
 125
 126 static int eps_target(struct cpufreq_policy *policy,
 127                                unsigned int target_freq,
 128                                unsigned int relation)
 129 {
 130         struct eps_cpu_data *centaur;
 131         unsigned int newstate = 0;
 132         unsigned int cpu = policy->cpu;
 133         unsigned int dest_state;
 134         int ret;
 135
 136         if (unlikely(eps_cpu[cpu] == NULL))
 137                 return -ENODEV;
 138         centaur = eps_cpu[cpu];
 139
 140         if (unlikely(cpufreq_frequency_table_target(policy,
 141                         &eps_cpu[cpu]->freq_table[0],
 142                         target_freq,
 143                         relation,
 144                         &newstate))) {
 145                 return -EINVAL;
 146         }
 147
 148         /* Make frequency transition */
 149         dest_state = centaur->freq_table[newstate].index & 0xffff;
 150         ret = eps_set_state(centaur, cpu, dest_state);
 151         if (ret)
 152                 printk(KERN_ERR "eps: Timeout!\n");
 153         return ret;
 154 }
 155
 156 static int eps_verify(struct cpufreq_policy *policy)
 157 {
 158         return cpufreq_frequency_table_verify(policy,
 159                         &eps_cpu[policy->cpu]->freq_table[0]);
 160 }
 161
 162 static int eps_cpu_init(struct cpufreq_policy *policy)
 163 {
 164         unsigned int i;
 165         u32 lo, hi;
 166         u64 val;
 167         u8 current_multiplier, current_voltage;
 168         u8 max_multiplier, max_voltage;
 169         u8 min_multiplier, min_voltage;
 170         u8 brand = 0;
 171         u32 fsb;
 172         struct eps_cpu_data *centaur;
 173         struct cpuinfo_x86 *c = &cpu_data(0);
 174         struct cpufreq_frequency_table *f_table;
 175         int k, step, voltage;
 176         int ret;
 177         int states;
 178
 179         if (policy->cpu != 0)
 180                 return -ENODEV;
 181
 182         /* Check brand */
 183         printk(KERN_INFO "eps: Detected VIA ");
 184
 185         switch (c->x86_model) {
 186         case 10:
 187                 rdmsr(0x1153, lo, hi);
 188                 brand = (((lo >> 2) ^ lo) >> 18) & 3;
 189                 printk(KERN_CONT "Model A ");
 190                 break;
 191         case 13:
 192                 rdmsr(0x1154, lo, hi);
 193                 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
 194                 printk(KERN_CONT "Model D ");
 195                 break;
 196         }
 197
 198         switch(brand) {
 199         case EPS_BRAND_C7M:
 200                 printk(KERN_CONT "C7-M\n");
 201                 break;
 202         case EPS_BRAND_C7:
 203                 printk(KERN_CONT "C7\n");
 204                 break;
 205         case EPS_BRAND_EDEN:
 206                 printk(KERN_CONT "Eden\n");
 207                 break;
 208         case EPS_BRAND_C7D:
 209                 printk(KERN_CONT "C7-D\n");
 210                 break;
 211         case EPS_BRAND_C3:
 212                 printk(KERN_CONT "C3\n");
 213                 return -ENODEV;
 214                 break;
 215         }
 216         /* Enable Enhanced PowerSaver */
 217         rdmsrl(MSR_IA32_MISC_ENABLE, val);
 218         if (!(val & 1 << 16)) {
 219                 val |= 1 << 16;
 220                 wrmsrl(MSR_IA32_MISC_ENABLE, val);
 221                 /* Can be locked at 0 */
 222                 rdmsrl(MSR_IA32_MISC_ENABLE, val);
 223                 if (!(val & 1 << 16)) {
 224                         printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
 225                         return -ENODEV;
 226                 }
 227         }
 228
 229         /* Print voltage and multiplier */
 230         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 231         current_voltage = lo & 0xff;
 232         printk(KERN_INFO "eps: Current voltage = %dmV\n", current_voltage * 16 + 700);
 233         current_multiplier = (lo >> 8) & 0xff;
 234         printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
 235
 236         /* Print limits */
 237         max_voltage = hi & 0xff;
 238         printk(KERN_INFO "eps: Highest voltage = %dmV\n", max_voltage * 16 + 700);
 239         max_multiplier = (hi >> 8) & 0xff;
 240         printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
 241         min_voltage = (hi >> 16) & 0xff;
 242         printk(KERN_INFO "eps: Lowest voltage = %dmV\n", min_voltage * 16 + 700);
 243         min_multiplier = (hi >> 24) & 0xff;
 244         printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
 245
 246         /* Sanity checks */
 247         if (current_multiplier == 0 || max_multiplier == 0
 248             || min_multiplier == 0)
 249                 return -EINVAL;
 250         if (current_multiplier > max_multiplier
 251             || max_multiplier <= min_multiplier)
 252                 return -EINVAL;
 253         if (current_voltage > 0x1f || max_voltage > 0x1f)
 254                 return -EINVAL;
 255         if (max_voltage < min_voltage)
 256                 return -EINVAL;
 257
 258         /* Calc FSB speed */
 259         fsb = cpu_khz / current_multiplier;
 260         /* Calc number of p-states supported */
 261         if (brand == EPS_BRAND_C7M)
 262                 states = max_multiplier - min_multiplier + 1;
 263         else
 264                 states = 2;
 265
 266         /* Allocate private data and frequency table for current cpu */
 267         centaur = kzalloc(sizeof(struct eps_cpu_data)
 268                     + (states + 1) * sizeof(struct cpufreq_frequency_table),
 269                     GFP_KERNEL);
 270         if (!centaur)
 271                 return -ENOMEM;
 272         eps_cpu[0] = centaur;
 273
 274         /* Copy basic values */
 275         centaur->fsb = fsb;
 276
 277         /* Fill frequency and MSR value table */
 278         f_table = &centaur->freq_table[0];
 279         if (brand != EPS_BRAND_C7M) {
 280                 f_table[0].frequency = fsb * min_multiplier;
 281                 f_table[0].index = (min_multiplier << 8) | min_voltage;
 282                 f_table[1].frequency = fsb * max_multiplier;
 283                 f_table[1].index = (max_multiplier << 8) | max_voltage;
 284                 f_table[2].frequency = CPUFREQ_TABLE_END;
 285         } else {
 286                 k = 0;
 287                 step = ((max_voltage - min_voltage) * 256)
 288                         / (max_multiplier - min_multiplier);
 289                 for (i = min_multiplier; i <= max_multiplier; i++) {
 290                         voltage = (k * step) / 256 + min_voltage;
 291                         f_table[k].frequency = fsb * i;
 292                         f_table[k].index = (i << 8) | voltage;
 293                         k++;
 294                 }
 295                 f_table[k].frequency = CPUFREQ_TABLE_END;
 296         }
 297
 298         policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
 299         policy->cur = fsb * current_multiplier;
 300
 301         ret = cpufreq_frequency_table_cpuinfo(policy, &centaur->freq_table[0]);
 302         if (ret) {
 303                 kfree(centaur);
 304                 return ret;
 305         }
 306
 307         cpufreq_frequency_table_get_attr(&centaur->freq_table[0], policy->cpu);
 308         return 0;
 309 }
 310
 311 static int eps_cpu_exit(struct cpufreq_policy *policy)
 312 {
 313         unsigned int cpu = policy->cpu;
 314         struct eps_cpu_data *centaur;
 315         u32 lo, hi;
 316
 317         if (eps_cpu[cpu] == NULL)
 318                 return -ENODEV;
 319         centaur = eps_cpu[cpu];
 320
 321         /* Get max frequency */
 322         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 323         /* Set max frequency */
 324         eps_set_state(centaur, cpu, hi & 0xffff);
 325         /* Bye */
 326         cpufreq_frequency_table_put_attr(policy->cpu);
 327         kfree(eps_cpu[cpu]);
 328         eps_cpu[cpu] = NULL;
 329         return 0;
 330 }
 331
 332 static struct freq_attr* eps_attr[] = {
 333         &cpufreq_freq_attr_scaling_available_freqs,
 334         NULL,
 335 };
 336
 337 static struct cpufreq_driver eps_driver = {
 338         .verify         = eps_verify,
 339         .target         = eps_target,
 340         .init           = eps_cpu_init,
 341         .exit           = eps_cpu_exit,
 342         .get            = eps_get,
 343         .name           = "e_powersaver",
 344         .owner          = THIS_MODULE,
 345         .attr           = eps_attr,
 346 };
 347
 348 static int __init eps_init(void)
 349 {
 350         struct cpuinfo_x86 *c = &cpu_data(0);
 351
 352         /* This driver will work only on Centaur C7 processors with
 353          * Enhanced SpeedStep/PowerSaver registers */
 354         if (c->x86_vendor != X86_VENDOR_CENTAUR
 355             || c->x86 != 6 || c->x86_model < 10)
 356                 return -ENODEV;
 357         if (!cpu_has(c, X86_FEATURE_EST))
 358                 return -ENODEV;
 359
 360         if (cpufreq_register_driver(&eps_driver))
 361                 return -EINVAL;
 362         return 0;
 363 }
 364
 365 static void __exit eps_exit(void)
 366 {
 367         cpufreq_unregister_driver(&eps_driver);
 368 }
 369
 370 MODULE_AUTHOR("Rafa³ Bilski <rafalbilski@interia.pl>");
 371 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
 372 MODULE_LICENSE("GPL");
 373
 374 module_init(eps_init);
 375 module_exit(eps_exit);