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
  30 /* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
  31 static struct cpufreq_frequency_table clock_ratio[] = {
  32         {45,  /* 000 -> 4.5x */ 0},
  33         {50,  /* 001 -> 5.0x */ 0},
  34         {40,  /* 010 -> 4.0x */ 0},
  35         {55,  /* 011 -> 5.5x */ 0},
  36         {20,  /* 100 -> 2.0x */ 0},
  37         {30,  /* 101 -> 3.0x */ 0},
  38         {60,  /* 110 -> 6.0x */ 0},
  39         {35,  /* 111 -> 3.5x */ 0},
  40         {0, CPUFREQ_TABLE_END}
  41 };
  42
  43
  44 /**
  45  * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
  46  *
  47  *   Returns the current setting of the frequency multiplier. Core clock
  48  * speed is frequency of the Front-Side Bus multiplied with this value.
  49  */
  50 static int powernow_k6_get_cpu_multiplier(void)
  51 {
  52         u64 invalue = 0;
  53         u32 msrval;
  54
  55         msrval = POWERNOW_IOPORT + 0x1;
  56         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
  57         invalue = inl(POWERNOW_IOPORT + 0x8);
  58         msrval = POWERNOW_IOPORT + 0x0;
  59         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
  60
  61         return clock_ratio[(invalue >> 5)&7].index;
  62 }
  63
  64
  65 /**
  66  * powernow_k6_set_state - set the PowerNow! multiplier
  67  * @best_i: clock_ratio[best_i] is the target multiplier
  68  *
  69  *   Tries to change the PowerNow! multiplier
  70  */
  71 static void powernow_k6_set_state(struct cpufreq_policy *policy,
  72                 unsigned int best_i)
  73 {
  74         unsigned long outvalue = 0, invalue = 0;
  75         unsigned long msrval;
  76         struct cpufreq_freqs freqs;
  77
  78         if (clock_ratio[best_i].index > max_multiplier) {
  79                 printk(KERN_ERR PFX "invalid target frequency\n");
  80                 return;
  81         }
  82
  83         freqs.old = busfreq * powernow_k6_get_cpu_multiplier();
  84         freqs.new = busfreq * clock_ratio[best_i].index;
  85
  86         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
  87
  88         /* we now need to transform best_i to the BVC format, see AMD#23446 */
  89
  90         outvalue = (1<<12) | (1<<10) | (1<<9) | (best_i<<5);
  91
  92         msrval = POWERNOW_IOPORT + 0x1;
  93         wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
  94         invalue = inl(POWERNOW_IOPORT + 0x8);
  95         invalue = invalue & 0xf;
  96         outvalue = outvalue | invalue;
  97         outl(outvalue , (POWERNOW_IOPORT + 0x8));
  98         msrval = POWERNOW_IOPORT + 0x0;
  99         wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
 100
 101         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 102
 103         return;
 104 }
 105
 106
 107 /**
 108  * powernow_k6_verify - verifies a new CPUfreq policy
 109  * @policy: new policy
 110  *
 111  * Policy must be within lowest and highest possible CPU Frequency,
 112  * and at least one possible state must be within min and max.
 113  */
 114 static int powernow_k6_verify(struct cpufreq_policy *policy)
 115 {
 116         return cpufreq_frequency_table_verify(policy, &clock_ratio[0]);
 117 }
 118
 119
 120 /**
 121  * powernow_k6_setpolicy - sets a new CPUFreq policy
 122  * @policy: new policy
 123  * @target_freq: the target frequency
 124  * @relation: how that frequency relates to achieved frequency
 125  *  (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 126  *
 127  * sets a new CPUFreq policy
 128  */
 129 static int powernow_k6_target(struct cpufreq_policy *policy,
 130                                unsigned int target_freq,
 131                                unsigned int relation)
 132 {
 133         unsigned int newstate = 0;
 134
 135         if (cpufreq_frequency_table_target(policy, &clock_ratio[0],
 136                                 target_freq, relation, &newstate))
 137                 return -EINVAL;
 138
 139         powernow_k6_set_state(policy, newstate);
 140
 141         return 0;
 142 }
 143
 144
 145 static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
 146 {
 147         unsigned int i, f;
 148         int result;
 149
 150         if (policy->cpu != 0)
 151                 return -ENODEV;
 152
 153         /* get frequencies */
 154         max_multiplier = powernow_k6_get_cpu_multiplier();
 155         busfreq = cpu_khz / max_multiplier;
 156
 157         /* table init */
 158         for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
 159                 f = clock_ratio[i].index;
 160                 if (f > max_multiplier)
 161                         clock_ratio[i].frequency = CPUFREQ_ENTRY_INVALID;
 162                 else
 163                         clock_ratio[i].frequency = busfreq * f;
 164         }
 165
 166         /* cpuinfo and default policy values */
 167         policy->cpuinfo.transition_latency = 200000;
 168         policy->cur = busfreq * max_multiplier;
 169
 170         result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio);
 171         if (result)
 172                 return result;
 173
 174         cpufreq_frequency_table_get_attr(clock_ratio, policy->cpu);
 175
 176         return 0;
 177 }
 178
 179
 180 static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
 181 {
 182         unsigned int i;
 183         for (i = 0; i < 8; i++) {
 184                 if (i == max_multiplier)
 185                         powernow_k6_set_state(policy, i);
 186         }
 187         cpufreq_frequency_table_put_attr(policy->cpu);
 188         return 0;
 189 }
 190
 191 static unsigned int powernow_k6_get(unsigned int cpu)
 192 {
 193         unsigned int ret;
 194         ret = (busfreq * powernow_k6_get_cpu_multiplier());
 195         return ret;
 196 }
 197
 198 static struct freq_attr *powernow_k6_attr[] = {
 199         &cpufreq_freq_attr_scaling_available_freqs,
 200         NULL,
 201 };
 202
 203 static struct cpufreq_driver powernow_k6_driver = {
 204         .verify         = powernow_k6_verify,
 205         .target         = powernow_k6_target,
 206         .init           = powernow_k6_cpu_init,
 207         .exit           = powernow_k6_cpu_exit,
 208         .get            = powernow_k6_get,
 209         .name           = "powernow-k6",
 210         .owner          = THIS_MODULE,
 211         .attr           = powernow_k6_attr,
 212 };
 213
 214 static const struct x86_cpu_id powernow_k6_ids[] = {
 215         { X86_VENDOR_AMD, 5, 12 },
 216         { X86_VENDOR_AMD, 5, 13 },
 217         {}
 218 };
 219 MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids);
 220
 221 /**
 222  * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
 223  *
 224  *   Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
 225  * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
 226  * on success.
 227  */
 228 static int __init powernow_k6_init(void)
 229 {
 230         if (!x86_match_cpu(powernow_k6_ids))
 231                 return -ENODEV;
 232
 233         if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
 234                 printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n");
 235                 return -EIO;
 236         }
 237
 238         if (cpufreq_register_driver(&powernow_k6_driver)) {
 239                 release_region(POWERNOW_IOPORT, 16);
 240                 return -EINVAL;
 241         }
 242
 243         return 0;
 244 }
 245
 246
 247 /**
 248  * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
 249  *
 250  *   Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
 251  */
 252 static void __exit powernow_k6_exit(void)
 253 {
 254         cpufreq_unregister_driver(&powernow_k6_driver);
 255         release_region(POWERNOW_IOPORT, 16);
 256 }
 257
 258
 259 MODULE_AUTHOR("Arjan van de Ven, Dave Jones <davej@redhat.com>, "
 260                 "Dominik Brodowski <linux@brodo.de>");
 261 MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
 262 MODULE_LICENSE("GPL");
 263
 264 module_init(powernow_k6_init);
 265 module_exit(powernow_k6_exit);