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