308 lines
8.2 KiB
C
308 lines
8.2 KiB
C
/*
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* This file was based upon code in Powertweak Linux (http://powertweak.sf.net)
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* (C) 2000-2003 Dave Jones, Arjan van de Ven, Janne Pänkälä,
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* Dominik Brodowski.
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*
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* Licensed under the terms of the GNU GPL License version 2.
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*
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* BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/cpufreq.h>
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#include <linux/ioport.h>
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#include <linux/timex.h>
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#include <linux/io.h>
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#include <asm/cpu_device_id.h>
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#include <asm/msr.h>
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#define POWERNOW_IOPORT 0xfff0 /* it doesn't matter where, as long
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as it is unused */
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#define PFX "powernow-k6: "
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static unsigned int busfreq; /* FSB, in 10 kHz */
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static unsigned int max_multiplier;
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static unsigned int param_busfreq = 0;
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static unsigned int param_max_multiplier = 0;
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module_param_named(max_multiplier, param_max_multiplier, uint, S_IRUGO);
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MODULE_PARM_DESC(max_multiplier, "Maximum multiplier (allowed values: 20 30 35 40 45 50 55 60)");
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module_param_named(bus_frequency, param_busfreq, uint, S_IRUGO);
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MODULE_PARM_DESC(bus_frequency, "Bus frequency in kHz");
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/* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
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static struct cpufreq_frequency_table clock_ratio[] = {
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{0, 60, /* 110 -> 6.0x */ 0},
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{0, 55, /* 011 -> 5.5x */ 0},
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{0, 50, /* 001 -> 5.0x */ 0},
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{0, 45, /* 000 -> 4.5x */ 0},
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{0, 40, /* 010 -> 4.0x */ 0},
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{0, 35, /* 111 -> 3.5x */ 0},
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{0, 30, /* 101 -> 3.0x */ 0},
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{0, 20, /* 100 -> 2.0x */ 0},
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{0, 0, CPUFREQ_TABLE_END}
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};
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static const u8 index_to_register[8] = { 6, 3, 1, 0, 2, 7, 5, 4 };
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static const u8 register_to_index[8] = { 3, 2, 4, 1, 7, 6, 0, 5 };
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static const struct {
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unsigned freq;
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unsigned mult;
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} usual_frequency_table[] = {
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{ 400000, 40 }, // 100 * 4
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{ 450000, 45 }, // 100 * 4.5
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{ 475000, 50 }, // 95 * 5
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{ 500000, 50 }, // 100 * 5
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{ 506250, 45 }, // 112.5 * 4.5
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{ 533500, 55 }, // 97 * 5.5
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{ 550000, 55 }, // 100 * 5.5
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{ 562500, 50 }, // 112.5 * 5
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{ 570000, 60 }, // 95 * 6
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{ 600000, 60 }, // 100 * 6
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{ 618750, 55 }, // 112.5 * 5.5
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{ 660000, 55 }, // 120 * 5.5
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{ 675000, 60 }, // 112.5 * 6
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{ 720000, 60 }, // 120 * 6
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};
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#define FREQ_RANGE 3000
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/**
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* powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
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*
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* Returns the current setting of the frequency multiplier. Core clock
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* speed is frequency of the Front-Side Bus multiplied with this value.
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*/
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static int powernow_k6_get_cpu_multiplier(void)
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{
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unsigned long invalue = 0;
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u32 msrval;
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local_irq_disable();
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msrval = POWERNOW_IOPORT + 0x1;
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wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
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invalue = inl(POWERNOW_IOPORT + 0x8);
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msrval = POWERNOW_IOPORT + 0x0;
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wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
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local_irq_enable();
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return clock_ratio[register_to_index[(invalue >> 5)&7]].driver_data;
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}
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static void powernow_k6_set_cpu_multiplier(unsigned int best_i)
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{
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unsigned long outvalue, invalue;
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unsigned long msrval;
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unsigned long cr0;
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/* we now need to transform best_i to the BVC format, see AMD#23446 */
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/*
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* The processor doesn't respond to inquiry cycles while changing the
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* frequency, so we must disable cache.
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*/
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local_irq_disable();
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cr0 = read_cr0();
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write_cr0(cr0 | X86_CR0_CD);
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wbinvd();
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outvalue = (1<<12) | (1<<10) | (1<<9) | (index_to_register[best_i]<<5);
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msrval = POWERNOW_IOPORT + 0x1;
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wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
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invalue = inl(POWERNOW_IOPORT + 0x8);
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invalue = invalue & 0x1f;
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outvalue = outvalue | invalue;
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outl(outvalue, (POWERNOW_IOPORT + 0x8));
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msrval = POWERNOW_IOPORT + 0x0;
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wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
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write_cr0(cr0);
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local_irq_enable();
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}
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/**
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* powernow_k6_target - set the PowerNow! multiplier
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* @best_i: clock_ratio[best_i] is the target multiplier
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*
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* Tries to change the PowerNow! multiplier
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*/
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static int powernow_k6_target(struct cpufreq_policy *policy,
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unsigned int best_i)
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{
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if (clock_ratio[best_i].driver_data > max_multiplier) {
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printk(KERN_ERR PFX "invalid target frequency\n");
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return -EINVAL;
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}
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powernow_k6_set_cpu_multiplier(best_i);
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return 0;
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}
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static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
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{
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struct cpufreq_frequency_table *pos;
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unsigned int i, f;
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unsigned khz;
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if (policy->cpu != 0)
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return -ENODEV;
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max_multiplier = 0;
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khz = cpu_khz;
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for (i = 0; i < ARRAY_SIZE(usual_frequency_table); i++) {
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if (khz >= usual_frequency_table[i].freq - FREQ_RANGE &&
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khz <= usual_frequency_table[i].freq + FREQ_RANGE) {
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khz = usual_frequency_table[i].freq;
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max_multiplier = usual_frequency_table[i].mult;
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break;
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}
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}
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if (param_max_multiplier) {
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cpufreq_for_each_entry(pos, clock_ratio)
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if (pos->driver_data == param_max_multiplier) {
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max_multiplier = param_max_multiplier;
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goto have_max_multiplier;
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}
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printk(KERN_ERR "powernow-k6: invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n");
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return -EINVAL;
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}
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if (!max_multiplier) {
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printk(KERN_WARNING "powernow-k6: unknown frequency %u, cannot determine current multiplier\n", khz);
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printk(KERN_WARNING "powernow-k6: use module parameters max_multiplier and bus_frequency\n");
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return -EOPNOTSUPP;
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}
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have_max_multiplier:
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param_max_multiplier = max_multiplier;
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if (param_busfreq) {
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if (param_busfreq >= 50000 && param_busfreq <= 150000) {
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busfreq = param_busfreq / 10;
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goto have_busfreq;
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}
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printk(KERN_ERR "powernow-k6: invalid bus_frequency parameter, allowed range 50000 - 150000 kHz\n");
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return -EINVAL;
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}
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busfreq = khz / max_multiplier;
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have_busfreq:
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param_busfreq = busfreq * 10;
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/* table init */
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cpufreq_for_each_entry(pos, clock_ratio) {
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f = pos->driver_data;
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if (f > max_multiplier)
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pos->frequency = CPUFREQ_ENTRY_INVALID;
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else
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pos->frequency = busfreq * f;
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}
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/* cpuinfo and default policy values */
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policy->cpuinfo.transition_latency = 500000;
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return cpufreq_table_validate_and_show(policy, clock_ratio);
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}
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static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
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{
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unsigned int i;
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for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
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if (clock_ratio[i].driver_data == max_multiplier) {
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struct cpufreq_freqs freqs;
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freqs.old = policy->cur;
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freqs.new = clock_ratio[i].frequency;
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freqs.flags = 0;
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cpufreq_freq_transition_begin(policy, &freqs);
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powernow_k6_target(policy, i);
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cpufreq_freq_transition_end(policy, &freqs, 0);
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break;
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}
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}
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return 0;
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}
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static unsigned int powernow_k6_get(unsigned int cpu)
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{
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unsigned int ret;
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ret = (busfreq * powernow_k6_get_cpu_multiplier());
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return ret;
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}
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static struct cpufreq_driver powernow_k6_driver = {
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.verify = cpufreq_generic_frequency_table_verify,
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.target_index = powernow_k6_target,
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.init = powernow_k6_cpu_init,
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.exit = powernow_k6_cpu_exit,
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.get = powernow_k6_get,
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.name = "powernow-k6",
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.attr = cpufreq_generic_attr,
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};
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static const struct x86_cpu_id powernow_k6_ids[] = {
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{ X86_VENDOR_AMD, 5, 12 },
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{ X86_VENDOR_AMD, 5, 13 },
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{}
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};
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MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids);
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/**
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* powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
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*
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* Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
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* devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
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* on success.
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*/
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static int __init powernow_k6_init(void)
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{
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if (!x86_match_cpu(powernow_k6_ids))
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return -ENODEV;
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if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
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printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n");
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return -EIO;
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}
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if (cpufreq_register_driver(&powernow_k6_driver)) {
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release_region(POWERNOW_IOPORT, 16);
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return -EINVAL;
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}
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return 0;
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}
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/**
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* powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
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*
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* Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
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*/
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static void __exit powernow_k6_exit(void)
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{
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cpufreq_unregister_driver(&powernow_k6_driver);
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release_region(POWERNOW_IOPORT, 16);
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}
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MODULE_AUTHOR("Arjan van de Ven, Dave Jones <davej@redhat.com>, "
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"Dominik Brodowski <linux@brodo.de>");
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MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
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MODULE_LICENSE("GPL");
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module_init(powernow_k6_init);
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module_exit(powernow_k6_exit);
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