kernel/2.6.29.6-aldebaran-rt/arch/x86/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 <linux/timex.h>
  19 #include <linux/io.h>
  20
  21 #define POWERNOW_IOPORT 0xfff0          /* it doesn't matter where, as long
  22                                            as it is unused */
  23
  24 static unsigned int                     busfreq;   /* FSB, in 10 kHz */
  25 static unsigned int                     max_multiplier;
  26
  27
  28 /* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
  29 static struct cpufreq_frequency_table clock_ratio[] = {
  30         {45,  /* 000 -> 4.5x */ 0},
  31         {50,  /* 001 -> 5.0x */ 0},
  32         {40,  /* 010 -> 4.0x */ 0},
  33         {55,  /* 011 -> 5.5x */ 0},
  34         {20,  /* 100 -> 2.0x */ 0},
  35         {30,  /* 101 -> 3.0x */ 0},
  36         {60,  /* 110 -> 6.0x */ 0},
  37         {35,  /* 111 -> 3.5x */ 0},
  38         {0, CPUFREQ_TABLE_END}
  39 };
  40
  41
  42 /**
  43  * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
  44  *
  45  *   Returns the current setting of the frequency multiplier. Core clock
  46  * speed is frequency of the Front-Side Bus multiplied with this value.
  47  */
  48 static int powernow_k6_get_cpu_multiplier(void)
  49 {
  50         u64             invalue = 0;
  51         u32             msrval;
  52
  53         msrval = POWERNOW_IOPORT + 0x1;
  54         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
  55         invalue = inl(POWERNOW_IOPORT + 0x8);
  56         msrval = POWERNOW_IOPORT + 0x0;
  57         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
  58
  59         return clock_ratio[(invalue >> 5)&7].index;
  60 }
  61
  62
  63 /**
  64  * powernow_k6_set_state - set the PowerNow! multiplier
  65  * @best_i: clock_ratio[best_i] is the target multiplier
  66  *
  67  *   Tries to change the PowerNow! multiplier
  68  */
  69 static void powernow_k6_set_state(unsigned int best_i)
  70 {
  71         unsigned long           outvalue = 0, invalue = 0;
  72         unsigned long           msrval;
  73         struct cpufreq_freqs    freqs;
  74
  75         if (clock_ratio[best_i].index > max_multiplier) {
  76                 printk(KERN_ERR "cpufreq: invalid target frequency\n");
  77                 return;
  78         }
  79
  80         freqs.old = busfreq * powernow_k6_get_cpu_multiplier();
  81         freqs.new = busfreq * clock_ratio[best_i].index;
  82         freqs.cpu = 0; /* powernow-k6.c is UP only driver */
  83
  84         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
  85
  86         /* we now need to transform best_i to the BVC format, see AMD#23446 */
  87
  88         outvalue = (1<<12) | (1<<10) | (1<<9) | (best_i<<5);
  89
  90         msrval = POWERNOW_IOPORT + 0x1;
  91         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
  92         invalue = inl(POWERNOW_IOPORT + 0x8);
  93         invalue = invalue & 0xf;
  94         outvalue = outvalue | invalue;
  95         outl(outvalue , (POWERNOW_IOPORT + 0x8));
  96         msrval = POWERNOW_IOPORT + 0x0;
  97         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
  98
  99         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 100
 101         return;
 102 }
 103
 104
 105 /**
 106  * powernow_k6_verify - verifies a new CPUfreq policy
 107  * @policy: new policy
 108  *
 109  * Policy must be within lowest and highest possible CPU Frequency,
 110  * and at least one possible state must be within min and max.
 111  */
 112 static int powernow_k6_verify(struct cpufreq_policy *policy)
 113 {
 114         return cpufreq_frequency_table_verify(policy, &clock_ratio[0]);
 115 }
 116
 117
 118 /**
 119  * powernow_k6_setpolicy - sets a new CPUFreq policy
 120  * @policy: new policy
 121  * @target_freq: the target frequency
 122  * @relation: how that frequency relates to achieved frequency (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 123  *
 124  * sets a new CPUFreq policy
 125  */
 126 static int powernow_k6_target(struct cpufreq_policy *policy,
 127                                unsigned int target_freq,
 128                                unsigned int relation)
 129 {
 130         unsigned int    newstate = 0;
 131
 132         if (cpufreq_frequency_table_target(policy, &clock_ratio[0], target_freq, relation, &newstate))
 133                 return -EINVAL;
 134
 135         powernow_k6_set_state(newstate);
 136
 137         return 0;
 138 }
 139
 140
 141 static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
 142 {
 143         unsigned int i;
 144         int result;
 145
 146         if (policy->cpu != 0)
 147                 return -ENODEV;
 148
 149         /* get frequencies */
 150         max_multiplier = powernow_k6_get_cpu_multiplier();
 151         busfreq = cpu_khz / max_multiplier;
 152
 153         /* table init */
 154         for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
 155                 if (clock_ratio[i].index > max_multiplier)
 156                         clock_ratio[i].frequency = CPUFREQ_ENTRY_INVALID;
 157                 else
 158                         clock_ratio[i].frequency = busfreq * clock_ratio[i].index;
 159         }
 160
 161         /* cpuinfo and default policy values */
 162         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 163         policy->cur = busfreq * max_multiplier;
 164
 165         result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio);
 166         if (result)
 167                 return result;
 168
 169         cpufreq_frequency_table_get_attr(clock_ratio, policy->cpu);
 170
 171         return 0;
 172 }
 173
 174
 175 static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
 176 {
 177         unsigned int i;
 178         for (i = 0; i < 8; i++) {
 179                 if (i == max_multiplier)
 180                         powernow_k6_set_state(i);
 181         }
 182         cpufreq_frequency_table_put_attr(policy->cpu);
 183         return 0;
 184 }
 185
 186 static unsigned int powernow_k6_get(unsigned int cpu)
 187 {
 188         return busfreq * powernow_k6_get_cpu_multiplier();
 189 }
 190
 191 static struct freq_attr *powernow_k6_attr[] = {
 192         &cpufreq_freq_attr_scaling_available_freqs,
 193         NULL,
 194 };
 195
 196 static struct cpufreq_driver powernow_k6_driver = {
 197         .verify         = powernow_k6_verify,
 198         .target         = powernow_k6_target,
 199         .init           = powernow_k6_cpu_init,
 200         .exit           = powernow_k6_cpu_exit,
 201         .get            = powernow_k6_get,
 202         .name           = "powernow-k6",
 203         .owner          = THIS_MODULE,
 204         .attr           = powernow_k6_attr,
 205 };
 206
 207
 208 /**
 209  * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
 210  *
 211  *   Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
 212  * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
 213  * on success.
 214  */
 215 static int __init powernow_k6_init(void)
 216 {
 217         struct cpuinfo_x86 *c = &cpu_data(0);
 218
 219         if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 5) ||
 220                 ((c->x86_model != 12) && (c->x86_model != 13)))
 221                 return -ENODEV;
 222
 223         if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
 224                 printk("cpufreq: PowerNow IOPORT region already used.\n");
 225                 return -EIO;
 226         }
 227
 228         if (cpufreq_register_driver(&powernow_k6_driver)) {
 229                 release_region(POWERNOW_IOPORT, 16);
 230                 return -EINVAL;
 231         }
 232
 233         return 0;
 234 }
 235
 236
 237 /**
 238  * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
 239  *
 240  *   Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
 241  */
 242 static void __exit powernow_k6_exit(void)
 243 {
 244         cpufreq_unregister_driver(&powernow_k6_driver);
 245         release_region(POWERNOW_IOPORT, 16);
 246 }
 247
 248
 249 MODULE_AUTHOR("Arjan van de Ven, Dave Jones <davej@redhat.com>, Dominik Brodowski <linux@brodo.de>");
 250 MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
 251 MODULE_LICENSE("GPL");
 252
 253 module_init(powernow_k6_init);
 254 module_exit(powernow_k6_exit);