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/msr.h>
  20
  21 #define POWERNOW_IOPORT 0xfff0          /* it doesn't matter where, as long
  22                                            as it is unused */
  23
  24 #define PFX "powernow-k6: "
  25 static unsigned int                     busfreq;   /* FSB, in 10 kHz */
  26 static unsigned int                     max_multiplier;
  27
  28
  29 /* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
  30 static struct cpufreq_frequency_table clock_ratio[] = {
  31         {45,  /* 000 -> 4.5x */ 0},
  32         {50,  /* 001 -> 5.0x */ 0},
  33         {40,  /* 010 -> 4.0x */ 0},
  34         {55,  /* 011 -> 5.5x */ 0},
  35         {20,  /* 100 -> 2.0x */ 0},
  36         {30,  /* 101 -> 3.0x */ 0},
  37         {60,  /* 110 -> 6.0x */ 0},
  38         {35,  /* 111 -> 3.5x */ 0},
  39         {0, CPUFREQ_TABLE_END}
  40 };
  41
  42
  43 /**
  44  * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
  45  *
  46  *   Returns the current setting of the frequency multiplier. Core clock
  47  * speed is frequency of the Front-Side Bus multiplied with this value.
  48  */
  49 static int powernow_k6_get_cpu_multiplier(void)
  50 {
  51         u64 invalue = 0;
  52         u32 msrval;
  53
  54         msrval = POWERNOW_IOPORT + 0x1;
  55         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
  56         invalue = inl(POWERNOW_IOPORT + 0x8);
  57         msrval = POWERNOW_IOPORT + 0x0;
  58         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
  59
  60         return clock_ratio[(invalue >> 5)&7].index;
  61 }
  62
  63
  64 /**
  65  * powernow_k6_set_state - set the PowerNow! multiplier
  66  * @best_i: clock_ratio[best_i] is the target multiplier
  67  *
  68  *   Tries to change the PowerNow! multiplier
  69  */
  70 static void powernow_k6_set_state(unsigned int best_i)
  71 {
  72         unsigned long outvalue = 0, invalue = 0;
  73         unsigned long msrval;
  74         struct cpufreq_freqs freqs;
  75
  76         if (clock_ratio[best_i].index > max_multiplier) {
  77                 printk(KERN_ERR PFX "invalid target frequency\n");
  78                 return;
  79         }
  80
  81         freqs.old = busfreq * powernow_k6_get_cpu_multiplier();
  82         freqs.new = busfreq * clock_ratio[best_i].index;
  83         freqs.cpu = 0; /* powernow-k6.c is UP only driver */
  84
  85         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
  86
  87         /* we now need to transform best_i to the BVC format, see AMD#23446 */
  88
  89         outvalue = (1<<12) | (1<<10) | (1<<9) | (best_i<<5);
  90
  91         msrval = POWERNOW_IOPORT + 0x1;
  92         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
  93         invalue = inl(POWERNOW_IOPORT + 0x8);
  94         invalue = invalue & 0xf;
  95         outvalue = outvalue | invalue;
  96         outl(outvalue , (POWERNOW_IOPORT + 0x8));
  97         msrval = POWERNOW_IOPORT + 0x0;
  98         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
  99
 100         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 101
 102         return;
 103 }
 104
 105
 106 /**
 107  * powernow_k6_verify - verifies a new CPUfreq policy
 108  * @policy: new policy
 109  *
 110  * Policy must be within lowest and highest possible CPU Frequency,
 111  * and at least one possible state must be within min and max.
 112  */
 113 static int powernow_k6_verify(struct cpufreq_policy *policy)
 114 {
 115         return cpufreq_frequency_table_verify(policy, &clock_ratio[0]);
 116 }
 117
 118
 119 /**
 120  * powernow_k6_setpolicy - sets a new CPUFreq policy
 121  * @policy: new policy
 122  * @target_freq: the target frequency
 123  * @relation: how that frequency relates to achieved frequency
 124  *  (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 125  *
 126  * sets a new CPUFreq policy
 127  */
 128 static int powernow_k6_target(struct cpufreq_policy *policy,
 129                                unsigned int target_freq,
 130                                unsigned int relation)
 131 {
 132         unsigned int newstate = 0;
 133
 134         if (cpufreq_frequency_table_target(policy, &clock_ratio[0],
 135                                 target_freq, relation, &newstate))
 136                 return -EINVAL;
 137
 138         powernow_k6_set_state(newstate);
 139
 140         return 0;
 141 }
 142
 143
 144 static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
 145 {
 146         unsigned int i, f;
 147         int result;
 148
 149         if (policy->cpu != 0)
 150                 return -ENODEV;
 151
 152         /* get frequencies */
 153         max_multiplier = powernow_k6_get_cpu_multiplier();
 154         busfreq = cpu_khz / max_multiplier;
 155
 156         /* table init */
 157         for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
 158                 f = clock_ratio[i].index;
 159                 if (f > max_multiplier)
 160                         clock_ratio[i].frequency = CPUFREQ_ENTRY_INVALID;
 161                 else
 162                         clock_ratio[i].frequency = busfreq * f;
 163         }
 164
 165         /* cpuinfo and default policy values */
 166         policy->cpuinfo.transition_latency = 200000;
 167         policy->cur = busfreq * max_multiplier;
 168
 169         result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio);
 170         if (result)
 171                 return result;
 172
 173         cpufreq_frequency_table_get_attr(clock_ratio, policy->cpu);
 174
 175         return 0;
 176 }
 177
 178
 179 static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
 180 {
 181         unsigned int i;
 182         for (i = 0; i < 8; i++) {
 183                 if (i == max_multiplier)
 184                         powernow_k6_set_state(i);
 185         }
 186         cpufreq_frequency_table_put_attr(policy->cpu);
 187         return 0;
 188 }
 189
 190 static unsigned int powernow_k6_get(unsigned int cpu)
 191 {
 192         unsigned int ret;
 193         ret = (busfreq * powernow_k6_get_cpu_multiplier());
 194         return ret;
 195 }
 196
 197 static struct freq_attr *powernow_k6_attr[] = {
 198         &cpufreq_freq_attr_scaling_available_freqs,
 199         NULL,
 200 };
 201
 202 static struct cpufreq_driver powernow_k6_driver = {
 203         .verify         = powernow_k6_verify,
 204         .target         = powernow_k6_target,
 205         .init           = powernow_k6_cpu_init,
 206         .exit           = powernow_k6_cpu_exit,
 207         .get            = powernow_k6_get,
 208         .name           = "powernow-k6",
 209         .owner          = THIS_MODULE,
 210         .attr           = powernow_k6_attr,
 211 };
 212
 213
 214 /**
 215  * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
 216  *
 217  *   Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
 218  * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
 219  * on success.
 220  */
 221 static int __init powernow_k6_init(void)
 222 {
 223         struct cpuinfo_x86 *c = &cpu_data(0);
 224
 225         if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 5) ||
 226                 ((c->x86_model != 12) && (c->x86_model != 13)))
 227                 return -ENODEV;
 228
 229         if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
 230                 printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n");
 231                 return -EIO;
 232         }
 233
 234         if (cpufreq_register_driver(&powernow_k6_driver)) {
 235                 release_region(POWERNOW_IOPORT, 16);
 236                 return -EINVAL;
 237         }
 238
 239         return 0;
 240 }
 241
 242
 243 /**
 244  * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
 245  *
 246  *   Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
 247  */
 248 static void __exit powernow_k6_exit(void)
 249 {
 250         cpufreq_unregister_driver(&powernow_k6_driver);
 251         release_region(POWERNOW_IOPORT, 16);
 252 }
 253
 254
 255 MODULE_AUTHOR("Arjan van de Ven, Dave Jones <davej@redhat.com>, "
 256                 "Dominik Brodowski <linux@brodo.de>");
 257 MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
 258 MODULE_LICENSE("GPL");
 259
 260 module_init(powernow_k6_init);
 261 module_exit(powernow_k6_exit);