drivers/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/timex.h>
  17 #include <linux/io.h>
  18
  19 #include <asm/cpu_device_id.h>
  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         {60,  /* 110 -> 6.0x */ 0},
  41         {55,  /* 011 -> 5.5x */ 0},
  42         {50,  /* 001 -> 5.0x */ 0},
  43         {45,  /* 000 -> 4.5x */ 0},
  44         {40,  /* 010 -> 4.0x */ 0},
  45         {35,  /* 111 -> 3.5x */ 0},
  46         {30,  /* 101 -> 3.0x */ 0},
  47         {20,  /* 100 -> 2.0x */ 0},
  48         {0, CPUFREQ_TABLE_END}
  49 };
  50
  51 static const u8 index_to_register[8] = { 6, 3, 1, 0, 2, 7, 5, 4 };
  52 static const u8 register_to_index[8] = { 3, 2, 4, 1, 7, 6, 0, 5 };
  53
  54 static const struct {
  55         unsigned freq;
  56         unsigned mult;
  57 } usual_frequency_table[] = {
  58         { 400000, 40 }, // 100   * 4
  59         { 450000, 45 }, // 100   * 4.5
  60         { 475000, 50 }, //  95   * 5
  61         { 500000, 50 }, // 100   * 5
  62         { 506250, 45 }, // 112.5 * 4.5
  63         { 533500, 55 }, //  97   * 5.5
  64         { 550000, 55 }, // 100   * 5.5
  65         { 562500, 50 }, // 112.5 * 5
  66         { 570000, 60 }, //  95   * 6
  67         { 600000, 60 }, // 100   * 6
  68         { 618750, 55 }, // 112.5 * 5.5
  69         { 660000, 55 }, // 120   * 5.5
  70         { 675000, 60 }, // 112.5 * 6
  71         { 720000, 60 }, // 120   * 6
  72 };
  73
  74 #define FREQ_RANGE              3000
  75
  76 /**
  77  * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
  78  *
  79  * Returns the current setting of the frequency multiplier. Core clock
  80  * speed is frequency of the Front-Side Bus multiplied with this value.
  81  */
  82 static int powernow_k6_get_cpu_multiplier(void)
  83 {
  84         unsigned long invalue = 0;
  85         u32 msrval;
  86
  87         local_irq_disable();
  88
  89         msrval = POWERNOW_IOPORT + 0x1;
  90         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
  91         invalue = inl(POWERNOW_IOPORT + 0x8);
  92         msrval = POWERNOW_IOPORT + 0x0;
  93         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
  94
  95         local_irq_enable();
  96
  97         return clock_ratio[register_to_index[(invalue >> 5)&7]].index;
  98 }
  99
 100 static void powernow_k6_set_cpu_multiplier(unsigned int best_i)
 101 {
 102         unsigned long outvalue, invalue;
 103         unsigned long msrval;
 104         unsigned long cr0;
 105
 106         /* we now need to transform best_i to the BVC format, see AMD#23446 */
 107
 108         /*
 109          * The processor doesn't respond to inquiry cycles while changing the
 110          * frequency, so we must disable cache.
 111          */
 112         local_irq_disable();
 113         cr0 = read_cr0();
 114         write_cr0(cr0 | X86_CR0_CD);
 115         wbinvd();
 116
 117         outvalue = (1<<12) | (1<<10) | (1<<9) | (index_to_register[best_i]<<5);
 118
 119         msrval = POWERNOW_IOPORT + 0x1;
 120         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
 121         invalue = inl(POWERNOW_IOPORT + 0x8);
 122         invalue = invalue & 0x1f;
 123         outvalue = outvalue | invalue;
 124         outl(outvalue, (POWERNOW_IOPORT + 0x8));
 125         msrval = POWERNOW_IOPORT + 0x0;
 126         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
 127
 128         write_cr0(cr0);
 129         local_irq_enable();
 130 }
 131
 132 /**
 133  * powernow_k6_set_state - set the PowerNow! multiplier
 134  * @best_i: clock_ratio[best_i] is the target multiplier
 135  *
 136  *   Tries to change the PowerNow! multiplier
 137  */
 138 static void powernow_k6_set_state(struct cpufreq_policy *policy,
 139                 unsigned int best_i)
 140 {
 141         struct cpufreq_freqs freqs;
 142
 143         if (clock_ratio[best_i].index > max_multiplier) {
 144                 printk(KERN_ERR PFX "invalid target frequency\n");
 145                 return;
 146         }
 147
 148         freqs.old = busfreq * powernow_k6_get_cpu_multiplier();
 149         freqs.new = busfreq * clock_ratio[best_i].index;
 150
 151         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 152
 153         powernow_k6_set_cpu_multiplier(best_i);
 154
 155         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 156
 157         return;
 158 }
 159
 160
 161 /**
 162  * powernow_k6_verify - verifies a new CPUfreq policy
 163  * @policy: new policy
 164  *
 165  * Policy must be within lowest and highest possible CPU Frequency,
 166  * and at least one possible state must be within min and max.
 167  */
 168 static int powernow_k6_verify(struct cpufreq_policy *policy)
 169 {
 170         return cpufreq_frequency_table_verify(policy, &clock_ratio[0]);
 171 }
 172
 173
 174 /**
 175  * powernow_k6_setpolicy - sets a new CPUFreq policy
 176  * @policy: new policy
 177  * @target_freq: the target frequency
 178  * @relation: how that frequency relates to achieved frequency
 179  *  (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 180  *
 181  * sets a new CPUFreq policy
 182  */
 183 static int powernow_k6_target(struct cpufreq_policy *policy,
 184                                unsigned int target_freq,
 185                                unsigned int relation)
 186 {
 187         unsigned int newstate = 0;
 188
 189         if (cpufreq_frequency_table_target(policy, &clock_ratio[0],
 190                                 target_freq, relation, &newstate))
 191                 return -EINVAL;
 192
 193         powernow_k6_set_state(policy, newstate);
 194
 195         return 0;
 196 }
 197
 198 static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
 199 {
 200         unsigned int i, f;
 201         int result;
 202         unsigned khz;
 203
 204         if (policy->cpu != 0)
 205                 return -ENODEV;
 206
 207         max_multiplier = 0;
 208         khz = cpu_khz;
 209         for (i = 0; i < ARRAY_SIZE(usual_frequency_table); i++) {
 210                 if (khz >= usual_frequency_table[i].freq - FREQ_RANGE &&
 211                     khz <= usual_frequency_table[i].freq + FREQ_RANGE) {
 212                         khz = usual_frequency_table[i].freq;
 213                         max_multiplier = usual_frequency_table[i].mult;
 214                         break;
 215                 }
 216         }
 217         if (param_max_multiplier) {
 218                 for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
 219                         if (clock_ratio[i].index == param_max_multiplier) {
 220                                 max_multiplier = param_max_multiplier;
 221                                 goto have_max_multiplier;
 222                         }
 223                 }
 224                 printk(KERN_ERR "powernow-k6: invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n");
 225                 return -EINVAL;
 226         }
 227
 228         if (!max_multiplier) {
 229                 printk(KERN_WARNING "powernow-k6: unknown frequency %u, cannot determine current multiplier\n", khz);
 230                 printk(KERN_WARNING "powernow-k6: use module parameters max_multiplier and bus_frequency\n");
 231                 return -EOPNOTSUPP;
 232         }
 233
 234 have_max_multiplier:
 235         param_max_multiplier = max_multiplier;
 236
 237         if (param_busfreq) {
 238                 if (param_busfreq >= 50000 && param_busfreq <= 150000) {
 239                         busfreq = param_busfreq / 10;
 240                         goto have_busfreq;
 241                 }
 242                 printk(KERN_ERR "powernow-k6: invalid bus_frequency parameter, allowed range 50000 - 150000 kHz\n");
 243                 return -EINVAL;
 244         }
 245
 246         busfreq = khz / max_multiplier;
 247 have_busfreq:
 248         param_busfreq = busfreq * 10;
 249
 250         /* table init */
 251         for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
 252                 f = clock_ratio[i].index;
 253                 if (f > max_multiplier)
 254                         clock_ratio[i].frequency = CPUFREQ_ENTRY_INVALID;
 255                 else
 256                         clock_ratio[i].frequency = busfreq * f;
 257         }
 258
 259         /* cpuinfo and default policy values */
 260         policy->cpuinfo.transition_latency = 500000;
 261         policy->cur = busfreq * max_multiplier;
 262
 263         result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio);
 264         if (result)
 265                 return result;
 266
 267         cpufreq_frequency_table_get_attr(clock_ratio, policy->cpu);
 268
 269         return 0;
 270 }
 271
 272
 273 static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
 274 {
 275         unsigned int i;
 276         for (i = 0; i < 8; i++) {
 277                 if (i == max_multiplier)
 278                         powernow_k6_set_state(policy, i);
 279         }
 280         cpufreq_frequency_table_put_attr(policy->cpu);
 281         return 0;
 282 }
 283
 284 static unsigned int powernow_k6_get(unsigned int cpu)
 285 {
 286         unsigned int ret;
 287         ret = (busfreq * powernow_k6_get_cpu_multiplier());
 288         return ret;
 289 }
 290
 291 static struct freq_attr *powernow_k6_attr[] = {
 292         &cpufreq_freq_attr_scaling_available_freqs,
 293         NULL,
 294 };
 295
 296 static struct cpufreq_driver powernow_k6_driver = {
 297         .verify         = powernow_k6_verify,
 298         .target         = powernow_k6_target,
 299         .init           = powernow_k6_cpu_init,
 300         .exit           = powernow_k6_cpu_exit,
 301         .get            = powernow_k6_get,
 302         .name           = "powernow-k6",
 303         .owner          = THIS_MODULE,
 304         .attr           = powernow_k6_attr,
 305 };
 306
 307 static const struct x86_cpu_id powernow_k6_ids[] = {
 308         { X86_VENDOR_AMD, 5, 12 },
 309         { X86_VENDOR_AMD, 5, 13 },
 310         {}
 311 };
 312 MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids);
 313
 314 /**
 315  * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
 316  *
 317  *   Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
 318  * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
 319  * on success.
 320  */
 321 static int __init powernow_k6_init(void)
 322 {
 323         if (!x86_match_cpu(powernow_k6_ids))
 324                 return -ENODEV;
 325
 326         if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
 327                 printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n");
 328                 return -EIO;
 329         }
 330
 331         if (cpufreq_register_driver(&powernow_k6_driver)) {
 332                 release_region(POWERNOW_IOPORT, 16);
 333                 return -EINVAL;
 334         }
 335
 336         return 0;
 337 }
 338
 339
 340 /**
 341  * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
 342  *
 343  *   Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
 344  */
 345 static void __exit powernow_k6_exit(void)
 346 {
 347         cpufreq_unregister_driver(&powernow_k6_driver);
 348         release_region(POWERNOW_IOPORT, 16);
 349 }
 350
 351
 352 MODULE_AUTHOR("Arjan van de Ven, Dave Jones <davej@redhat.com>, "
 353                 "Dominik Brodowski <linux@brodo.de>");
 354 MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
 355 MODULE_LICENSE("GPL");
 356
 357 module_init(powernow_k6_init);
 358 module_exit(powernow_k6_exit);