arch/x86/kernel/cpu/cpufreq/powernow-k6.c

   1 /*
   2  *  This file was based upon code in Powertweak Linux (http://powertweak.sf.net)
   3  *  (C) 2000-2003  Dave Jones, Arjan van de Ven, Janne Pänkälä,
   4  *                 Dominik Brodowski.
   5  *
   6  *  Licensed under the terms of the GNU GPL License version 2.
   7  *
   8  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/cpufreq.h>
  15 #include <linux/ioport.h>
  16 #include <linux/slab.h>
  17 #include <linux/timex.h>
  18 #include <linux/io.h>
  19
  20 #include <asm/msr.h>
  21
  22 #define POWERNOW_IOPORT 0xfff0          /* it doesn't matter where, as long
  23                                            as it is unused */
  24
  25 #define PFX "powernow-k6: "
  26 static unsigned int                     busfreq;   /* FSB, in 10 kHz */
  27 static unsigned int                     max_multiplier;
  28
  29 static unsigned int                     param_busfreq = 0;
  30 static unsigned int                     param_max_multiplier = 0;
  31
  32 module_param_named(max_multiplier, param_max_multiplier, uint, S_IRUGO);
  33 MODULE_PARM_DESC(max_multiplier, "Maximum multiplier (allowed values: 20 30 35 40 45 50 55 60)");
  34
  35 module_param_named(bus_frequency, param_busfreq, uint, S_IRUGO);
  36 MODULE_PARM_DESC(bus_frequency, "Bus frequency in kHz");
  37
  38 /* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
  39 static struct cpufreq_frequency_table clock_ratio[] = {
  40         {45,  /* 000 -> 4.5x */ 0},
  41         {50,  /* 001 -> 5.0x */ 0},
  42         {40,  /* 010 -> 4.0x */ 0},
  43         {55,  /* 011 -> 5.5x */ 0},
  44         {20,  /* 100 -> 2.0x */ 0},
  45         {30,  /* 101 -> 3.0x */ 0},
  46         {60,  /* 110 -> 6.0x */ 0},
  47         {35,  /* 111 -> 3.5x */ 0},
  48         {0, CPUFREQ_TABLE_END}
  49 };
  50
  51 static const struct {
  52         unsigned freq;
  53         unsigned mult;
  54 } usual_frequency_table[] = {
  55         { 400000, 40 }, // 100   * 4
  56         { 450000, 45 }, // 100   * 4.5
  57         { 475000, 50 }, //  95   * 5
  58         { 500000, 50 }, // 100   * 5
  59         { 506250, 45 }, // 112.5 * 4.5
  60         { 533500, 55 }, //  97   * 5.5
  61         { 550000, 55 }, // 100   * 5.5
  62         { 562500, 50 }, // 112.5 * 5
  63         { 570000, 60 }, //  95   * 6
  64         { 600000, 60 }, // 100   * 6
  65         { 618750, 55 }, // 112.5 * 5.5
  66         { 660000, 55 }, // 120   * 5.5
  67         { 675000, 60 }, // 112.5 * 6
  68         { 720000, 60 }, // 120   * 6
  69 };
  70
  71 #define FREQ_RANGE              3000
  72
  73 /**
  74  * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
  75  *
  76  * Returns the current setting of the frequency multiplier. Core clock
  77  * speed is frequency of the Front-Side Bus multiplied with this value.
  78  */
  79 static int powernow_k6_get_cpu_multiplier(void)
  80 {
  81         unsigned long invalue = 0;
  82         u32 msrval;
  83
  84         local_irq_disable();
  85
  86         msrval = POWERNOW_IOPORT + 0x1;
  87         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
  88         invalue = inl(POWERNOW_IOPORT + 0x8);
  89         msrval = POWERNOW_IOPORT + 0x0;
  90         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
  91
  92         local_irq_enable();
  93
  94         return clock_ratio[(invalue >> 5)&7].index;
  95 }
  96
  97 static void powernow_k6_set_cpu_multiplier(unsigned int best_i)
  98 {
  99         unsigned long outvalue, invalue;
 100         unsigned long msrval;
 101         unsigned long cr0;
 102
 103         /* we now need to transform best_i to the BVC format, see AMD#23446 */
 104
 105         /*
 106          * The processor doesn't respond to inquiry cycles while changing the
 107          * frequency, so we must disable cache.
 108          */
 109         local_irq_disable();
 110         cr0 = read_cr0();
 111         write_cr0(cr0 | X86_CR0_CD);
 112         wbinvd();
 113
 114         outvalue = (1<<12) | (1<<10) | (1<<9) | (best_i<<5);
 115
 116         msrval = POWERNOW_IOPORT + 0x1;
 117         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
 118         invalue = inl(POWERNOW_IOPORT + 0x8);
 119         invalue = invalue & 0x1f;
 120         outvalue = outvalue | invalue;
 121         outl(outvalue, (POWERNOW_IOPORT + 0x8));
 122         msrval = POWERNOW_IOPORT + 0x0;
 123         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
 124
 125         write_cr0(cr0);
 126         local_irq_enable();
 127 }
 128
 129 /**
 130  * powernow_k6_set_state - set the PowerNow! multiplier
 131  * @best_i: clock_ratio[best_i] is the target multiplier
 132  *
 133  *   Tries to change the PowerNow! multiplier
 134  */
 135 static void powernow_k6_set_state(unsigned int best_i)
 136 {
 137         struct cpufreq_freqs freqs;
 138
 139         if (clock_ratio[best_i].index > max_multiplier) {
 140                 printk(KERN_ERR PFX "invalid target frequency\n");
 141                 return;
 142         }
 143
 144         freqs.old = busfreq * powernow_k6_get_cpu_multiplier();
 145         freqs.new = busfreq * clock_ratio[best_i].index;
 146         freqs.cpu = 0; /* powernow-k6.c is UP only driver */
 147
 148         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 149
 150         powernow_k6_set_cpu_multiplier(best_i);
 151
 152         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 153
 154         return;
 155 }
 156
 157
 158 /**
 159  * powernow_k6_verify - verifies a new CPUfreq policy
 160  * @policy: new policy
 161  *
 162  * Policy must be within lowest and highest possible CPU Frequency,
 163  * and at least one possible state must be within min and max.
 164  */
 165 static int powernow_k6_verify(struct cpufreq_policy *policy)
 166 {
 167         return cpufreq_frequency_table_verify(policy, &clock_ratio[0]);
 168 }
 169
 170
 171 /**
 172  * powernow_k6_setpolicy - sets a new CPUFreq policy
 173  * @policy: new policy
 174  * @target_freq: the target frequency
 175  * @relation: how that frequency relates to achieved frequency
 176  *  (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 177  *
 178  * sets a new CPUFreq policy
 179  */
 180 static int powernow_k6_target(struct cpufreq_policy *policy,
 181                                unsigned int target_freq,
 182                                unsigned int relation)
 183 {
 184         unsigned int newstate = 0;
 185
 186         if (cpufreq_frequency_table_target(policy, &clock_ratio[0],
 187                                 target_freq, relation, &newstate))
 188                 return -EINVAL;
 189
 190         powernow_k6_set_state(newstate);
 191
 192         return 0;
 193 }
 194
 195 static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
 196 {
 197         unsigned int i, f;
 198         int result;
 199         unsigned khz;
 200
 201         if (policy->cpu != 0)
 202                 return -ENODEV;
 203
 204         max_multiplier = 0;
 205         khz = cpu_khz;
 206         for (i = 0; i < ARRAY_SIZE(usual_frequency_table); i++) {
 207                 if (khz >= usual_frequency_table[i].freq - FREQ_RANGE &&
 208                     khz <= usual_frequency_table[i].freq + FREQ_RANGE) {
 209                         khz = usual_frequency_table[i].freq;
 210                         max_multiplier = usual_frequency_table[i].mult;
 211                         break;
 212                 }
 213         }
 214         if (param_max_multiplier) {
 215                 for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
 216                         if (clock_ratio[i].index == param_max_multiplier) {
 217                                 max_multiplier = param_max_multiplier;
 218                                 goto have_max_multiplier;
 219                         }
 220                 }
 221                 printk(KERN_ERR "powernow-k6: invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n");
 222                 return -EINVAL;
 223         }
 224
 225         if (!max_multiplier) {
 226                 printk(KERN_WARNING "powernow-k6: unknown frequency %u, cannot determine current multiplier\n", khz);
 227                 printk(KERN_WARNING "powernow-k6: use module parameters max_multiplier and bus_frequency\n");
 228                 return -EOPNOTSUPP;
 229         }
 230
 231 have_max_multiplier:
 232         param_max_multiplier = max_multiplier;
 233
 234         if (param_busfreq) {
 235                 if (param_busfreq >= 50000 && param_busfreq <= 150000) {
 236                         busfreq = param_busfreq / 10;
 237                         goto have_busfreq;
 238                 }
 239                 printk(KERN_ERR "powernow-k6: invalid bus_frequency parameter, allowed range 50000 - 150000 kHz\n");
 240                 return -EINVAL;
 241         }
 242
 243         busfreq = khz / max_multiplier;
 244 have_busfreq:
 245         param_busfreq = busfreq * 10;
 246
 247         /* table init */
 248         for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
 249                 f = clock_ratio[i].index;
 250                 if (f > max_multiplier)
 251                         clock_ratio[i].frequency = CPUFREQ_ENTRY_INVALID;
 252                 else
 253                         clock_ratio[i].frequency = busfreq * f;
 254         }
 255
 256         /* cpuinfo and default policy values */
 257         policy->cpuinfo.transition_latency = 500000;
 258         policy->cur = busfreq * max_multiplier;
 259
 260         result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio);
 261         if (result)
 262                 return result;
 263
 264         cpufreq_frequency_table_get_attr(clock_ratio, policy->cpu);
 265
 266         return 0;
 267 }
 268
 269
 270 static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
 271 {
 272         unsigned int i;
 273         for (i = 0; i < 8; i++) {
 274                 if (i == max_multiplier)
 275                         powernow_k6_set_state(i);
 276         }
 277         cpufreq_frequency_table_put_attr(policy->cpu);
 278         return 0;
 279 }
 280
 281 static unsigned int powernow_k6_get(unsigned int cpu)
 282 {
 283         unsigned int ret;
 284         ret = (busfreq * powernow_k6_get_cpu_multiplier());
 285         return ret;
 286 }
 287
 288 static struct freq_attr *powernow_k6_attr[] = {
 289         &cpufreq_freq_attr_scaling_available_freqs,
 290         NULL,
 291 };
 292
 293 static struct cpufreq_driver powernow_k6_driver = {
 294         .verify         = powernow_k6_verify,
 295         .target         = powernow_k6_target,
 296         .init           = powernow_k6_cpu_init,
 297         .exit           = powernow_k6_cpu_exit,
 298         .get            = powernow_k6_get,
 299         .name           = "powernow-k6",
 300         .owner          = THIS_MODULE,
 301         .attr           = powernow_k6_attr,
 302 };
 303
 304
 305 /**
 306  * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
 307  *
 308  *   Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
 309  * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
 310  * on success.
 311  */
 312 static int __init powernow_k6_init(void)
 313 {
 314         struct cpuinfo_x86 *c = &cpu_data(0);
 315
 316         if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 5) ||
 317                 ((c->x86_model != 12) && (c->x86_model != 13)))
 318                 return -ENODEV;
 319
 320         if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
 321                 printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n");
 322                 return -EIO;
 323         }
 324
 325         if (cpufreq_register_driver(&powernow_k6_driver)) {
 326                 release_region(POWERNOW_IOPORT, 16);
 327                 return -EINVAL;
 328         }
 329
 330         return 0;
 331 }
 332
 333
 334 /**
 335  * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
 336  *
 337  *   Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
 338  */
 339 static void __exit powernow_k6_exit(void)
 340 {
 341         cpufreq_unregister_driver(&powernow_k6_driver);
 342         release_region(POWERNOW_IOPORT, 16);
 343 }
 344
 345
 346 MODULE_AUTHOR("Arjan van de Ven, Dave Jones <davej@redhat.com>, "
 347                 "Dominik Brodowski <linux@brodo.de>");
 348 MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
 349 MODULE_LICENSE("GPL");
 350
 351 module_init(powernow_k6_init);
 352 module_exit(powernow_k6_exit);