--- /dev/null
+/*
+ * Based on documentation provided by Dave Jones. Thanks!
+ *
+ * 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/slab.h>
+
+#include <asm/msr.h>
+#include <asm/tsc.h>
+#include <asm/timex.h>
+#include <asm/io.h>
+#include <asm/delay.h>
+
+#define EPS_BRAND_C7M 0
+#define EPS_BRAND_C7 1
+#define EPS_BRAND_EDEN 2
+#define EPS_BRAND_C3 3
+
+struct eps_cpu_data {
+ u32 fsb;
+ struct cpufreq_frequency_table freq_table[];
+};
+
+static struct eps_cpu_data *eps_cpu[NR_CPUS];
+
+
+static unsigned int eps_get(unsigned int cpu)
+{
+ struct eps_cpu_data *centaur;
+ u32 lo, hi;
+
+ if (cpu)
+ return 0;
+ centaur = eps_cpu[cpu];
+ if (centaur == NULL)
+ return 0;
+
+ /* Return current frequency */
+ rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
+ return centaur->fsb * ((lo >> 8) & 0xff);
+}
+
+static int eps_set_state(struct eps_cpu_data *centaur,
+ unsigned int cpu,
+ u32 dest_state)
+{
+ struct cpufreq_freqs freqs;
+ u32 lo, hi;
+ int err = 0;
+ int i;
+
+ freqs.old = eps_get(cpu);
+ freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
+ freqs.cpu = cpu;
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+ /* Wait while CPU is busy */
+ rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
+ i = 0;
+ while (lo & ((1 << 16) | (1 << 17))) {
+ udelay(16);
+ rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
+ i++;
+ if (unlikely(i > 64)) {
+ err = -ENODEV;
+ goto postchange;
+ }
+ }
+ /* Set new multiplier and voltage */
+ wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
+ /* Wait until transition end */
+ i = 0;
+ do {
+ udelay(16);
+ rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
+ i++;
+ if (unlikely(i > 64)) {
+ err = -ENODEV;
+ goto postchange;
+ }
+ } while (lo & ((1 << 16) | (1 << 17)));
+
+ /* Return current frequency */
+postchange:
+ rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
+ freqs.new = centaur->fsb * ((lo >> 8) & 0xff);
+
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+ return err;
+}
+
+static int eps_target(struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ struct eps_cpu_data *centaur;
+ unsigned int newstate = 0;
+ unsigned int cpu = policy->cpu;
+ unsigned int dest_state;
+ int ret;
+
+ if (unlikely(eps_cpu[cpu] == NULL))
+ return -ENODEV;
+ centaur = eps_cpu[cpu];
+
+ if (unlikely(cpufreq_frequency_table_target(policy,
+ &eps_cpu[cpu]->freq_table[0],
+ target_freq,
+ relation,
+ &newstate))) {
+ return -EINVAL;
+ }
+
+ /* Make frequency transition */
+ dest_state = centaur->freq_table[newstate].index & 0xffff;
+ ret = eps_set_state(centaur, cpu, dest_state);
+ if (ret)
+ printk(KERN_ERR "eps: Timeout!\n");
+ return ret;
+}
+
+static int eps_verify(struct cpufreq_policy *policy)
+{
+ return cpufreq_frequency_table_verify(policy,
+ &eps_cpu[policy->cpu]->freq_table[0]);
+}
+
+static int eps_cpu_init(struct cpufreq_policy *policy)
+{
+ unsigned int i;
+ u32 lo, hi;
+ u64 val;
+ u8 current_multiplier, current_voltage;
+ u8 max_multiplier, max_voltage;
+ u8 min_multiplier, min_voltage;
+ u8 brand;
+ u32 fsb;
+ struct eps_cpu_data *centaur;
+ struct cpufreq_frequency_table *f_table;
+ int k, step, voltage;
+ int ret;
+ int states;
+
+ if (policy->cpu != 0)
+ return -ENODEV;
+
+ /* Check brand */
+ printk("eps: Detected VIA ");
+ rdmsr(0x1153, lo, hi);
+ brand = (((lo >> 2) ^ lo) >> 18) & 3;
+ switch(brand) {
+ case EPS_BRAND_C7M:
+ printk("C7-M\n");
+ break;
+ case EPS_BRAND_C7:
+ printk("C7\n");
+ break;
+ case EPS_BRAND_EDEN:
+ printk("Eden\n");
+ break;
+ case EPS_BRAND_C3:
+ printk("C3\n");
+ return -ENODEV;
+ break;
+ }
+ /* Enable Enhanced PowerSaver */
+ rdmsrl(MSR_IA32_MISC_ENABLE, val);
+ if (!(val & 1 << 16)) {
+ val |= 1 << 16;
+ wrmsrl(MSR_IA32_MISC_ENABLE, val);
+ /* Can be locked at 0 */
+ rdmsrl(MSR_IA32_MISC_ENABLE, val);
+ if (!(val & 1 << 16)) {
+ printk("eps: Can't enable Enhanced PowerSaver\n");
+ return -ENODEV;
+ }
+ }
+
+ /* Print voltage and multiplier */
+ rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
+ current_voltage = lo & 0xff;
+ printk("eps: Current voltage = %dmV\n", current_voltage * 16 + 700);
+ current_multiplier = (lo >> 8) & 0xff;
+ printk("eps: Current multiplier = %d\n", current_multiplier);
+
+ /* Print limits */
+ max_voltage = hi & 0xff;
+ printk("eps: Highest voltage = %dmV\n", max_voltage * 16 + 700);
+ max_multiplier = (hi >> 8) & 0xff;
+ printk("eps: Highest multiplier = %d\n", max_multiplier);
+ min_voltage = (hi >> 16) & 0xff;
+ printk("eps: Lowest voltage = %dmV\n", min_voltage * 16 + 700);
+ min_multiplier = (hi >> 24) & 0xff;
+ printk("eps: Lowest multiplier = %d\n", min_multiplier);
+
+ /* Sanity checks */
+ if (current_multiplier == 0 || max_multiplier == 0
+ || min_multiplier == 0)
+ return -EINVAL;
+ if (current_multiplier > max_multiplier
+ || max_multiplier <= min_multiplier)
+ return -EINVAL;
+ if (current_voltage > 0x1c || max_voltage > 0x1c)
+ return -EINVAL;
+ if (max_voltage < min_voltage)
+ return -EINVAL;
+
+ /* Calc FSB speed */
+ fsb = cpu_khz / current_multiplier;
+ /* Calc number of p-states supported */
+ if (brand == EPS_BRAND_C7M)
+ states = max_multiplier - min_multiplier + 1;
+ else
+ states = 2;
+
+ /* Allocate private data and frequency table for current cpu */
+ centaur = kzalloc(sizeof(struct eps_cpu_data)
+ + (states + 1) * sizeof(struct cpufreq_frequency_table),
+ GFP_KERNEL);
+ if (!centaur)
+ return -ENOMEM;
+ eps_cpu[0] = centaur;
+
+ /* Copy basic values */
+ centaur->fsb = fsb;
+
+ /* Fill frequency and MSR value table */
+ f_table = ¢aur->freq_table[0];
+ if (brand == EPS_BRAND_EDEN) {
+ f_table[0].frequency = fsb * min_multiplier;
+ f_table[0].index = (min_multiplier << 8) | min_voltage;
+ f_table[1].frequency = fsb * max_multiplier;
+ f_table[1].index = (max_multiplier << 8) | max_voltage;
+ f_table[2].frequency = CPUFREQ_TABLE_END;
+ } else {
+ k = 0;
+ step = ((max_voltage - min_voltage) * 256)
+ / (max_multiplier - min_multiplier);
+ for (i = min_multiplier; i <= max_multiplier; i++) {
+ voltage = (k * step) / 256 + min_voltage;
+ f_table[k].frequency = fsb * i;
+ f_table[k].index = (i << 8) | voltage;
+ k++;
+ }
+ f_table[k].frequency = CPUFREQ_TABLE_END;
+ }
+
+ policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+ policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
+ policy->cur = fsb * current_multiplier;
+
+ ret = cpufreq_frequency_table_cpuinfo(policy, ¢aur->freq_table[0]);
+ if (ret) {
+ kfree(centaur);
+ return ret;
+ }
+
+ cpufreq_frequency_table_get_attr(¢aur->freq_table[0], policy->cpu);
+ return 0;
+}
+
+static int eps_cpu_exit(struct cpufreq_policy *policy)
+{
+ unsigned int cpu = policy->cpu;
+ struct eps_cpu_data *centaur;
+ u32 lo, hi;
+
+ if (eps_cpu[cpu] == NULL)
+ return -ENODEV;
+ centaur = eps_cpu[cpu];
+
+ /* Get max frequency */
+ rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
+ /* Set max frequency */
+ eps_set_state(centaur, cpu, hi & 0xffff);
+ /* Bye */
+ cpufreq_frequency_table_put_attr(policy->cpu);
+ kfree(eps_cpu[cpu]);
+ eps_cpu[cpu] = NULL;
+ return 0;
+}
+
+static struct freq_attr* eps_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL,
+};
+
+static struct cpufreq_driver eps_driver = {
+ .verify = eps_verify,
+ .target = eps_target,
+ .init = eps_cpu_init,
+ .exit = eps_cpu_exit,
+ .get = eps_get,
+ .name = "e_powersaver",
+ .owner = THIS_MODULE,
+ .attr = eps_attr,
+};
+
+static int __init eps_init(void)
+{
+ struct cpuinfo_x86 *c = cpu_data;
+
+ /* This driver will work only on Centaur C7 processors with
+ * Enhanced SpeedStep/PowerSaver registers */
+ if (c->x86_vendor != X86_VENDOR_CENTAUR
+ || c->x86 != 6 || c->x86_model != 10)
+ return -ENODEV;
+ if (!cpu_has(c, X86_FEATURE_EST))
+ return -ENODEV;
+
+ if (cpufreq_register_driver(&eps_driver))
+ return -EINVAL;
+ return 0;
+}
+
+static void __exit eps_exit(void)
+{
+ cpufreq_unregister_driver(&eps_driver);
+}
+
+MODULE_AUTHOR("Rafa³ Bilski <rafalbilski@interia.pl>");
+MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
+MODULE_LICENSE("GPL");
+
+module_init(eps_init);
+module_exit(eps_exit);
projects / linux-2.6 / commitdiff