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         {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
  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]].driver_data;
  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_target - 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 int powernow_k6_target(struct cpufreq_policy *policy,
 139                 unsigned int best_i)
 140 {
 141
 142         if (clock_ratio[best_i].driver_data > max_multiplier) {
 143                 printk(KERN_ERR PFX "invalid target frequency\n");
 144                 return -EINVAL;
 145         }
 146
 147         powernow_k6_set_cpu_multiplier(best_i);
 148
 149         return 0;
 150 }
 151
 152 static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
 153 {
 154         struct cpufreq_frequency_table *pos;
 155         unsigned int i, f;
 156         unsigned khz;
 157
 158         if (policy->cpu != 0)
 159                 return -ENODEV;
 160
 161         max_multiplier = 0;
 162         khz = cpu_khz;
 163         for (i = 0; i < ARRAY_SIZE(usual_frequency_table); i++) {
 164                 if (khz >= usual_frequency_table[i].freq - FREQ_RANGE &&
 165                     khz <= usual_frequency_table[i].freq + FREQ_RANGE) {
 166                         khz = usual_frequency_table[i].freq;
 167                         max_multiplier = usual_frequency_table[i].mult;
 168                         break;
 169                 }
 170         }
 171         if (param_max_multiplier) {
 172                 cpufreq_for_each_entry(pos, clock_ratio)
 173                         if (pos->driver_data == param_max_multiplier) {
 174                                 max_multiplier = param_max_multiplier;
 175                                 goto have_max_multiplier;
 176                         }
 177                 printk(KERN_ERR "powernow-k6: invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n");
 178                 return -EINVAL;
 179         }
 180
 181         if (!max_multiplier) {
 182                 printk(KERN_WARNING "powernow-k6: unknown frequency %u, cannot determine current multiplier\n", khz);
 183                 printk(KERN_WARNING "powernow-k6: use module parameters max_multiplier and bus_frequency\n");
 184                 return -EOPNOTSUPP;
 185         }
 186
 187 have_max_multiplier:
 188         param_max_multiplier = max_multiplier;
 189
 190         if (param_busfreq) {
 191                 if (param_busfreq >= 50000 && param_busfreq <= 150000) {
 192                         busfreq = param_busfreq / 10;
 193                         goto have_busfreq;
 194                 }
 195                 printk(KERN_ERR "powernow-k6: invalid bus_frequency parameter, allowed range 50000 - 150000 kHz\n");
 196                 return -EINVAL;
 197         }
 198
 199         busfreq = khz / max_multiplier;
 200 have_busfreq:
 201         param_busfreq = busfreq * 10;
 202
 203         /* table init */
 204         cpufreq_for_each_entry(pos, clock_ratio) {
 205                 f = pos->driver_data;
 206                 if (f > max_multiplier)
 207                         pos->frequency = CPUFREQ_ENTRY_INVALID;
 208                 else
 209                         pos->frequency = busfreq * f;
 210         }
 211
 212         /* cpuinfo and default policy values */
 213         policy->cpuinfo.transition_latency = 500000;
 214
 215         return cpufreq_table_validate_and_show(policy, clock_ratio);
 216 }
 217
 218
 219 static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
 220 {
 221         unsigned int i;
 222
 223         for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
 224                 if (clock_ratio[i].driver_data == max_multiplier) {
 225                         struct cpufreq_freqs freqs;
 226
 227                         freqs.old = policy->cur;
 228                         freqs.new = clock_ratio[i].frequency;
 229                         freqs.flags = 0;
 230
 231                         cpufreq_freq_transition_begin(policy, &freqs);
 232                         powernow_k6_target(policy, i);
 233                         cpufreq_freq_transition_end(policy, &freqs, 0);
 234                         break;
 235                 }
 236         }
 237         return 0;
 238 }
 239
 240 static unsigned int powernow_k6_get(unsigned int cpu)
 241 {
 242         unsigned int ret;
 243         ret = (busfreq * powernow_k6_get_cpu_multiplier());
 244         return ret;
 245 }
 246
 247 static struct cpufreq_driver powernow_k6_driver = {
 248         .verify         = cpufreq_generic_frequency_table_verify,
 249         .target_index   = powernow_k6_target,
 250         .init           = powernow_k6_cpu_init,
 251         .exit           = powernow_k6_cpu_exit,
 252         .get            = powernow_k6_get,
 253         .name           = "powernow-k6",
 254         .attr           = cpufreq_generic_attr,
 255 };
 256
 257 static const struct x86_cpu_id powernow_k6_ids[] = {
 258         { X86_VENDOR_AMD, 5, 12 },
 259         { X86_VENDOR_AMD, 5, 13 },
 260         {}
 261 };
 262 MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids);
 263
 264 /**
 265  * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
 266  *
 267  *   Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
 268  * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
 269  * on success.
 270  */
 271 static int __init powernow_k6_init(void)
 272 {
 273         if (!x86_match_cpu(powernow_k6_ids))
 274                 return -ENODEV;
 275
 276         if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
 277                 printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n");
 278                 return -EIO;
 279         }
 280
 281         if (cpufreq_register_driver(&powernow_k6_driver)) {
 282                 release_region(POWERNOW_IOPORT, 16);
 283                 return -EINVAL;
 284         }
 285
 286         return 0;
 287 }
 288
 289
 290 /**
 291  * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
 292  *
 293  *   Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
 294  */
 295 static void __exit powernow_k6_exit(void)
 296 {
 297         cpufreq_unregister_driver(&powernow_k6_driver);
 298         release_region(POWERNOW_IOPORT, 16);
 299 }
 300
 301
 302 MODULE_AUTHOR("Arjan van de Ven, Dave Jones <davej@redhat.com>, "
 303                 "Dominik Brodowski <linux@brodo.de>");
 304 MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
 305 MODULE_LICENSE("GPL");
 306
 307 module_init(powernow_k6_init);
 308 module_exit(powernow_k6_exit);