arch/i386/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, Dominik Brodowski.
   4  *
   5  *  Licensed under the terms of the GNU GPL License version 2.
   6  *
   7  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/cpufreq.h>
  14 #include <linux/ioport.h>
  15 #include <linux/slab.h>
  16
  17 #include <asm/msr.h>
  18 #include <asm/timex.h>
  19 #include <asm/io.h>
  20
  21
  22 #define POWERNOW_IOPORT 0xfff0         /* it doesn't matter where, as long
  23                                           as it is unused */
  24
  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 "cpufreq: 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 (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 124  *
 125  * sets a new CPUFreq policy
 126  */
 127 static int powernow_k6_target (struct cpufreq_policy *policy,
 128                                unsigned int target_freq,
 129                                unsigned int relation)
 130 {
 131         unsigned int    newstate = 0;
 132
 133         if (cpufreq_frequency_table_target(policy, &clock_ratio[0], target_freq, relation, &newstate))
 134                 return -EINVAL;
 135
 136         powernow_k6_set_state(newstate);
 137
 138         return 0;
 139 }
 140
 141
 142 static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
 143 {
 144         unsigned int i;
 145         int result;
 146
 147         if (policy->cpu != 0)
 148                 return -ENODEV;
 149
 150         /* get frequencies */
 151         max_multiplier = powernow_k6_get_cpu_multiplier();
 152         busfreq = cpu_khz / max_multiplier;
 153
 154         /* table init */
 155         for (i=0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
 156                 if (clock_ratio[i].index > max_multiplier)
 157                         clock_ratio[i].frequency = CPUFREQ_ENTRY_INVALID;
 158                 else
 159                         clock_ratio[i].frequency = busfreq * clock_ratio[i].index;
 160         }
 161
 162         /* cpuinfo and default policy values */
 163         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 164         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 165         policy->cur = busfreq * max_multiplier;
 166
 167         result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio);
 168         if (result)
 169                 return (result);
 170
 171         cpufreq_frequency_table_get_attr(clock_ratio, policy->cpu);
 172
 173         return 0;
 174 }
 175
 176
 177 static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
 178 {
 179         unsigned int i;
 180         for (i=0; i<8; i++) {
 181                 if (i==max_multiplier)
 182                         powernow_k6_set_state(i);
 183         }
 184         cpufreq_frequency_table_put_attr(policy->cpu);
 185         return 0;
 186 }
 187
 188 static unsigned int powernow_k6_get(unsigned int cpu)
 189 {
 190         return busfreq * powernow_k6_get_cpu_multiplier();
 191 }
 192
 193 static struct freq_attr* powernow_k6_attr[] = {
 194         &cpufreq_freq_attr_scaling_available_freqs,
 195         NULL,
 196 };
 197
 198 static struct cpufreq_driver powernow_k6_driver = {
 199         .verify         = powernow_k6_verify,
 200         .target         = powernow_k6_target,
 201         .init           = powernow_k6_cpu_init,
 202         .exit           = powernow_k6_cpu_exit,
 203         .get            = powernow_k6_get,
 204         .name           = "powernow-k6",
 205         .owner          = THIS_MODULE,
 206         .attr           = powernow_k6_attr,
 207 };
 208
 209
 210 /**
 211  * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
 212  *
 213  *   Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
 214  * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
 215  * on success.
 216  */
 217 static int __init powernow_k6_init(void)
 218 {
 219         struct cpuinfo_x86      *c = cpu_data;
 220
 221         if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 5) ||
 222                 ((c->x86_model != 12) && (c->x86_model != 13)))
 223                 return -ENODEV;
 224
 225         if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
 226                 printk("cpufreq: PowerNow IOPORT region already used.\n");
 227                 return -EIO;
 228         }
 229
 230         if (cpufreq_register_driver(&powernow_k6_driver)) {
 231                 release_region (POWERNOW_IOPORT, 16);
 232                 return -EINVAL;
 233         }
 234
 235         return 0;
 236 }
 237
 238
 239 /**
 240  * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
 241  *
 242  *   Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
 243  */
 244 static void __exit powernow_k6_exit(void)
 245 {
 246         cpufreq_unregister_driver(&powernow_k6_driver);
 247         release_region (POWERNOW_IOPORT, 16);
 248 }
 249
 250
 251 MODULE_AUTHOR ("Arjan van de Ven <arjanv@redhat.com>, Dave Jones <davej@codemonkey.org.uk>, Dominik Brodowski <linux@brodo.de>");
 252 MODULE_DESCRIPTION ("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
 253 MODULE_LICENSE ("GPL");
 254
 255 module_init(powernow_k6_init);
 256 module_exit(powernow_k6_exit);