--- /dev/null
+/*
+ * This file was based upon code in Powertweak Linux (http://powertweak.sf.net)
+ * (C) 2000-2003 Dave Jones, Arjan van de Ven, Janne Pänkälä,
+ * Dominik Brodowski.
+ *
+ * Licensed under the terms of the GNU GPL License version 2.
+ *
+ * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/ioport.h>
+#include <linux/timex.h>
+#include <linux/io.h>
+
+#include <asm/cpu_device_id.h>
+#include <asm/msr.h>
+
+#define POWERNOW_IOPORT 0xfff0 /* it doesn't matter where, as long
+ as it is unused */
+
+#define PFX "powernow-k6: "
+static unsigned int busfreq; /* FSB, in 10 kHz */
+static unsigned int max_multiplier;
+
+static unsigned int param_busfreq = 0;
+static unsigned int param_max_multiplier = 0;
+
+module_param_named(max_multiplier, param_max_multiplier, uint, S_IRUGO);
+MODULE_PARM_DESC(max_multiplier, "Maximum multiplier (allowed values: 20 30 35 40 45 50 55 60)");
+
+module_param_named(bus_frequency, param_busfreq, uint, S_IRUGO);
+MODULE_PARM_DESC(bus_frequency, "Bus frequency in kHz");
+
+/* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
+static struct cpufreq_frequency_table clock_ratio[] = {
+ {0, 60, /* 110 -> 6.0x */ 0},
+ {0, 55, /* 011 -> 5.5x */ 0},
+ {0, 50, /* 001 -> 5.0x */ 0},
+ {0, 45, /* 000 -> 4.5x */ 0},
+ {0, 40, /* 010 -> 4.0x */ 0},
+ {0, 35, /* 111 -> 3.5x */ 0},
+ {0, 30, /* 101 -> 3.0x */ 0},
+ {0, 20, /* 100 -> 2.0x */ 0},
+ {0, 0, CPUFREQ_TABLE_END}
+};
+
+static const u8 index_to_register[8] = { 6, 3, 1, 0, 2, 7, 5, 4 };
+static const u8 register_to_index[8] = { 3, 2, 4, 1, 7, 6, 0, 5 };
+
+static const struct {
+ unsigned freq;
+ unsigned mult;
+} usual_frequency_table[] = {
+ { 350000, 35 }, // 100 * 3.5
+ { 400000, 40 }, // 100 * 4
+ { 450000, 45 }, // 100 * 4.5
+ { 475000, 50 }, // 95 * 5
+ { 500000, 50 }, // 100 * 5
+ { 506250, 45 }, // 112.5 * 4.5
+ { 533500, 55 }, // 97 * 5.5
+ { 550000, 55 }, // 100 * 5.5
+ { 562500, 50 }, // 112.5 * 5
+ { 570000, 60 }, // 95 * 6
+ { 600000, 60 }, // 100 * 6
+ { 618750, 55 }, // 112.5 * 5.5
+ { 660000, 55 }, // 120 * 5.5
+ { 675000, 60 }, // 112.5 * 6
+ { 720000, 60 }, // 120 * 6
+};
+
+#define FREQ_RANGE 3000
+
+/**
+ * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
+ *
+ * Returns the current setting of the frequency multiplier. Core clock
+ * speed is frequency of the Front-Side Bus multiplied with this value.
+ */
+static int powernow_k6_get_cpu_multiplier(void)
+{
+ unsigned long invalue = 0;
+ u32 msrval;
+
+ local_irq_disable();
+
+ msrval = POWERNOW_IOPORT + 0x1;
+ wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
+ invalue = inl(POWERNOW_IOPORT + 0x8);
+ msrval = POWERNOW_IOPORT + 0x0;
+ wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
+
+ local_irq_enable();
+
+ return clock_ratio[register_to_index[(invalue >> 5)&7]].driver_data;
+}
+
+static void powernow_k6_set_cpu_multiplier(unsigned int best_i)
+{
+ unsigned long outvalue, invalue;
+ unsigned long msrval;
+ unsigned long cr0;
+
+ /* we now need to transform best_i to the BVC format, see AMD#23446 */
+
+ /*
+ * The processor doesn't respond to inquiry cycles while changing the
+ * frequency, so we must disable cache.
+ */
+ local_irq_disable();
+ cr0 = read_cr0();
+ write_cr0(cr0 | X86_CR0_CD);
+ wbinvd();
+
+ outvalue = (1<<12) | (1<<10) | (1<<9) | (index_to_register[best_i]<<5);
+
+ msrval = POWERNOW_IOPORT + 0x1;
+ wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
+ invalue = inl(POWERNOW_IOPORT + 0x8);
+ invalue = invalue & 0x1f;
+ outvalue = outvalue | invalue;
+ outl(outvalue, (POWERNOW_IOPORT + 0x8));
+ msrval = POWERNOW_IOPORT + 0x0;
+ wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
+
+ write_cr0(cr0);
+ local_irq_enable();
+}
+
+/**
+ * powernow_k6_target - set the PowerNow! multiplier
+ * @best_i: clock_ratio[best_i] is the target multiplier
+ *
+ * Tries to change the PowerNow! multiplier
+ */
+static int powernow_k6_target(struct cpufreq_policy *policy,
+ unsigned int best_i)
+{
+
+ if (clock_ratio[best_i].driver_data > max_multiplier) {
+ printk(KERN_ERR PFX "invalid target frequency\n");
+ return -EINVAL;
+ }
+
+ powernow_k6_set_cpu_multiplier(best_i);
+
+ return 0;
+}
+
+static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
+{
+ struct cpufreq_frequency_table *pos;
+ unsigned int i, f;
+ unsigned khz;
+
+ if (policy->cpu != 0)
+ return -ENODEV;
+
+ max_multiplier = 0;
+ khz = cpu_khz;
+ for (i = 0; i < ARRAY_SIZE(usual_frequency_table); i++) {
+ if (khz >= usual_frequency_table[i].freq - FREQ_RANGE &&
+ khz <= usual_frequency_table[i].freq + FREQ_RANGE) {
+ khz = usual_frequency_table[i].freq;
+ max_multiplier = usual_frequency_table[i].mult;
+ break;
+ }
+ }
+ if (param_max_multiplier) {
+ cpufreq_for_each_entry(pos, clock_ratio)
+ if (pos->driver_data == param_max_multiplier) {
+ max_multiplier = param_max_multiplier;
+ goto have_max_multiplier;
+ }
+ printk(KERN_ERR "powernow-k6: invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n");
+ return -EINVAL;
+ }
+
+ if (!max_multiplier) {
+ printk(KERN_WARNING "powernow-k6: unknown frequency %u, cannot determine current multiplier\n", khz);
+ printk(KERN_WARNING "powernow-k6: use module parameters max_multiplier and bus_frequency\n");
+ return -EOPNOTSUPP;
+ }
+
+have_max_multiplier:
+ param_max_multiplier = max_multiplier;
+
+ if (param_busfreq) {
+ if (param_busfreq >= 50000 && param_busfreq <= 150000) {
+ busfreq = param_busfreq / 10;
+ goto have_busfreq;
+ }
+ printk(KERN_ERR "powernow-k6: invalid bus_frequency parameter, allowed range 50000 - 150000 kHz\n");
+ return -EINVAL;
+ }
+
+ busfreq = khz / max_multiplier;
+have_busfreq:
+ param_busfreq = busfreq * 10;
+
+ /* table init */
+ cpufreq_for_each_entry(pos, clock_ratio) {
+ f = pos->driver_data;
+ if (f > max_multiplier)
+ pos->frequency = CPUFREQ_ENTRY_INVALID;
+ else
+ pos->frequency = busfreq * f;
+ }
+
+ /* cpuinfo and default policy values */
+ policy->cpuinfo.transition_latency = 500000;
+
+ return cpufreq_table_validate_and_show(policy, clock_ratio);
+}
+
+
+static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
+{
+ unsigned int i;
+
+ for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
+ if (clock_ratio[i].driver_data == max_multiplier) {
+ struct cpufreq_freqs freqs;
+
+ freqs.old = policy->cur;
+ freqs.new = clock_ratio[i].frequency;
+ freqs.flags = 0;
+
+ cpufreq_freq_transition_begin(policy, &freqs);
+ powernow_k6_target(policy, i);
+ cpufreq_freq_transition_end(policy, &freqs, 0);
+ break;
+ }
+ }
+ return 0;
+}
+
+static unsigned int powernow_k6_get(unsigned int cpu)
+{
+ unsigned int ret;
+ ret = (busfreq * powernow_k6_get_cpu_multiplier());
+ return ret;
+}
+
+static struct cpufreq_driver powernow_k6_driver = {
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = powernow_k6_target,
+ .init = powernow_k6_cpu_init,
+ .exit = powernow_k6_cpu_exit,
+ .get = powernow_k6_get,
+ .name = "powernow-k6",
+ .attr = cpufreq_generic_attr,
+};
+
+static const struct x86_cpu_id powernow_k6_ids[] = {
+ { X86_VENDOR_AMD, 5, 12 },
+ { X86_VENDOR_AMD, 5, 13 },
+ {}
+};
+MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids);
+
+/**
+ * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
+ *
+ * Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
+ * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
+ * on success.
+ */
+static int __init powernow_k6_init(void)
+{
+ if (!x86_match_cpu(powernow_k6_ids))
+ return -ENODEV;
+
+ if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
+ printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n");
+ return -EIO;
+ }
+
+ if (cpufreq_register_driver(&powernow_k6_driver)) {
+ release_region(POWERNOW_IOPORT, 16);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+
+/**
+ * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
+ *
+ * Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
+ */
+static void __exit powernow_k6_exit(void)
+{
+ cpufreq_unregister_driver(&powernow_k6_driver);
+ release_region(POWERNOW_IOPORT, 16);
+}
+
+
+MODULE_AUTHOR("Arjan van de Ven, Dave Jones, "
+ "Dominik Brodowski <linux@brodo.de>");
+MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
+MODULE_LICENSE("GPL");
+
+module_init(powernow_k6_init);
+module_exit(powernow_k6_exit);
Code Review / kvmfornfv.git / blobdiff