--- /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 <linux/timex.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+
+#include <asm/cpu_device_id.h>
+#include <asm/msr.h>
+#include <asm/tsc.h>
+
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+#include <linux/acpi.h>
+#include <acpi/processor.h>
+#endif
+
+#define EPS_BRAND_C7M 0
+#define EPS_BRAND_C7 1
+#define EPS_BRAND_EDEN 2
+#define EPS_BRAND_C3 3
+#define EPS_BRAND_C7D 4
+
+struct eps_cpu_data {
+ u32 fsb;
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+ u32 bios_limit;
+#endif
+ struct cpufreq_frequency_table freq_table[];
+};
+
+static struct eps_cpu_data *eps_cpu[NR_CPUS];
+
+/* Module parameters */
+static int freq_failsafe_off;
+static int voltage_failsafe_off;
+static int set_max_voltage;
+
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+static int ignore_acpi_limit;
+
+static struct acpi_processor_performance *eps_acpi_cpu_perf;
+
+/* Minimum necessary to get acpi_processor_get_bios_limit() working */
+static int eps_acpi_init(void)
+{
+ eps_acpi_cpu_perf = kzalloc(sizeof(*eps_acpi_cpu_perf),
+ GFP_KERNEL);
+ if (!eps_acpi_cpu_perf)
+ return -ENOMEM;
+
+ if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
+ GFP_KERNEL)) {
+ kfree(eps_acpi_cpu_perf);
+ eps_acpi_cpu_perf = NULL;
+ return -ENOMEM;
+ }
+
+ if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
+ free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
+ kfree(eps_acpi_cpu_perf);
+ eps_acpi_cpu_perf = NULL;
+ return -EIO;
+ }
+ return 0;
+}
+
+static int eps_acpi_exit(struct cpufreq_policy *policy)
+{
+ if (eps_acpi_cpu_perf) {
+ acpi_processor_unregister_performance(eps_acpi_cpu_perf, 0);
+ free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
+ kfree(eps_acpi_cpu_perf);
+ eps_acpi_cpu_perf = NULL;
+ }
+ return 0;
+}
+#endif
+
+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,
+ struct cpufreq_policy *policy,
+ u32 dest_state)
+{
+ u32 lo, hi;
+ int i;
+
+ /* 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)) {
+ return -ENODEV;
+ }
+ }
+ /* 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)) {
+ return -ENODEV;
+ }
+ } while (lo & ((1 << 16) | (1 << 17)));
+
+#ifdef DEBUG
+ {
+ u8 current_multiplier, current_voltage;
+
+ /* Print voltage and multiplier */
+ rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
+ current_voltage = lo & 0xff;
+ printk(KERN_INFO "eps: Current voltage = %dmV\n",
+ current_voltage * 16 + 700);
+ current_multiplier = (lo >> 8) & 0xff;
+ printk(KERN_INFO "eps: Current multiplier = %d\n",
+ current_multiplier);
+ }
+#endif
+ return 0;
+}
+
+static int eps_target(struct cpufreq_policy *policy, unsigned int index)
+{
+ struct eps_cpu_data *centaur;
+ unsigned int cpu = policy->cpu;
+ unsigned int dest_state;
+ int ret;
+
+ if (unlikely(eps_cpu[cpu] == NULL))
+ return -ENODEV;
+ centaur = eps_cpu[cpu];
+
+ /* Make frequency transition */
+ dest_state = centaur->freq_table[index].driver_data & 0xffff;
+ ret = eps_set_state(centaur, policy, dest_state);
+ if (ret)
+ printk(KERN_ERR "eps: Timeout!\n");
+ return ret;
+}
+
+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 = 0;
+ u32 fsb;
+ struct eps_cpu_data *centaur;
+ struct cpuinfo_x86 *c = &cpu_data(0);
+ struct cpufreq_frequency_table *f_table;
+ int k, step, voltage;
+ int ret;
+ int states;
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+ unsigned int limit;
+#endif
+
+ if (policy->cpu != 0)
+ return -ENODEV;
+
+ /* Check brand */
+ printk(KERN_INFO "eps: Detected VIA ");
+
+ switch (c->x86_model) {
+ case 10:
+ rdmsr(0x1153, lo, hi);
+ brand = (((lo >> 2) ^ lo) >> 18) & 3;
+ printk(KERN_CONT "Model A ");
+ break;
+ case 13:
+ rdmsr(0x1154, lo, hi);
+ brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
+ printk(KERN_CONT "Model D ");
+ break;
+ }
+
+ switch (brand) {
+ case EPS_BRAND_C7M:
+ printk(KERN_CONT "C7-M\n");
+ break;
+ case EPS_BRAND_C7:
+ printk(KERN_CONT "C7\n");
+ break;
+ case EPS_BRAND_EDEN:
+ printk(KERN_CONT "Eden\n");
+ break;
+ case EPS_BRAND_C7D:
+ printk(KERN_CONT "C7-D\n");
+ break;
+ case EPS_BRAND_C3:
+ printk(KERN_CONT "C3\n");
+ return -ENODEV;
+ break;
+ }
+ /* Enable Enhanced PowerSaver */
+ rdmsrl(MSR_IA32_MISC_ENABLE, val);
+ if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
+ val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
+ wrmsrl(MSR_IA32_MISC_ENABLE, val);
+ /* Can be locked at 0 */
+ rdmsrl(MSR_IA32_MISC_ENABLE, val);
+ if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
+ printk(KERN_INFO "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(KERN_INFO "eps: Current voltage = %dmV\n",
+ current_voltage * 16 + 700);
+ current_multiplier = (lo >> 8) & 0xff;
+ printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
+
+ /* Print limits */
+ max_voltage = hi & 0xff;
+ printk(KERN_INFO "eps: Highest voltage = %dmV\n",
+ max_voltage * 16 + 700);
+ max_multiplier = (hi >> 8) & 0xff;
+ printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
+ min_voltage = (hi >> 16) & 0xff;
+ printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
+ min_voltage * 16 + 700);
+ min_multiplier = (hi >> 24) & 0xff;
+ printk(KERN_INFO "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 > 0x1f || max_voltage > 0x1f)
+ return -EINVAL;
+ if (max_voltage < min_voltage
+ || current_voltage < min_voltage
+ || current_voltage > max_voltage)
+ return -EINVAL;
+
+ /* Check for systems using underclocked CPU */
+ if (!freq_failsafe_off && max_multiplier != current_multiplier) {
+ printk(KERN_INFO "eps: Your processor is running at different "
+ "frequency then its maximum. Aborting.\n");
+ printk(KERN_INFO "eps: You can use freq_failsafe_off option "
+ "to disable this check.\n");
+ return -EINVAL;
+ }
+ if (!voltage_failsafe_off && max_voltage != current_voltage) {
+ printk(KERN_INFO "eps: Your processor is running at different "
+ "voltage then its maximum. Aborting.\n");
+ printk(KERN_INFO "eps: You can use voltage_failsafe_off "
+ "option to disable this check.\n");
+ return -EINVAL;
+ }
+
+ /* Calc FSB speed */
+ fsb = cpu_khz / current_multiplier;
+
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+ /* Check for ACPI processor speed limit */
+ if (!ignore_acpi_limit && !eps_acpi_init()) {
+ if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
+ printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
+ limit/1000000,
+ (limit%1000000)/10000);
+ eps_acpi_exit(policy);
+ /* Check if max_multiplier is in BIOS limits */
+ if (limit && max_multiplier * fsb > limit) {
+ printk(KERN_INFO "eps: Aborting.\n");
+ return -EINVAL;
+ }
+ }
+ }
+#endif
+
+ /* Allow user to set lower maximum voltage then that reported
+ * by processor */
+ if (brand == EPS_BRAND_C7M && set_max_voltage) {
+ u32 v;
+
+ /* Change mV to something hardware can use */
+ v = (set_max_voltage - 700) / 16;
+ /* Check if voltage is within limits */
+ if (v >= min_voltage && v <= max_voltage) {
+ printk(KERN_INFO "eps: Setting %dmV as maximum.\n",
+ v * 16 + 700);
+ max_voltage = v;
+ }
+ }
+
+ /* 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(*centaur)
+ + (states + 1) * sizeof(struct cpufreq_frequency_table),
+ GFP_KERNEL);
+ if (!centaur)
+ return -ENOMEM;
+ eps_cpu[0] = centaur;
+
+ /* Copy basic values */
+ centaur->fsb = fsb;
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+ centaur->bios_limit = limit;
+#endif
+
+ /* Fill frequency and MSR value table */
+ f_table = ¢aur->freq_table[0];
+ if (brand != EPS_BRAND_C7M) {
+ f_table[0].frequency = fsb * min_multiplier;
+ f_table[0].driver_data = (min_multiplier << 8) | min_voltage;
+ f_table[1].frequency = fsb * max_multiplier;
+ f_table[1].driver_data = (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].driver_data = (i << 8) | voltage;
+ k++;
+ }
+ f_table[k].frequency = CPUFREQ_TABLE_END;
+ }
+
+ policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
+
+ ret = cpufreq_table_validate_and_show(policy, ¢aur->freq_table[0]);
+ if (ret) {
+ kfree(centaur);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int eps_cpu_exit(struct cpufreq_policy *policy)
+{
+ unsigned int cpu = policy->cpu;
+
+ /* Bye */
+ kfree(eps_cpu[cpu]);
+ eps_cpu[cpu] = NULL;
+ return 0;
+}
+
+static struct cpufreq_driver eps_driver = {
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = eps_target,
+ .init = eps_cpu_init,
+ .exit = eps_cpu_exit,
+ .get = eps_get,
+ .name = "e_powersaver",
+ .attr = cpufreq_generic_attr,
+};
+
+
+/* This driver will work only on Centaur C7 processors with
+ * Enhanced SpeedStep/PowerSaver registers */
+static const struct x86_cpu_id eps_cpu_id[] = {
+ { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST },
+ {}
+};
+MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
+
+static int __init eps_init(void)
+{
+ if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
+ return -ENODEV;
+ if (cpufreq_register_driver(&eps_driver))
+ return -EINVAL;
+ return 0;
+}
+
+static void __exit eps_exit(void)
+{
+ cpufreq_unregister_driver(&eps_driver);
+}
+
+/* Allow user to overclock his machine or to change frequency to higher after
+ * unloading module */
+module_param(freq_failsafe_off, int, 0644);
+MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
+module_param(voltage_failsafe_off, int, 0644);
+MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+module_param(ignore_acpi_limit, int, 0644);
+MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
+#endif
+module_param(set_max_voltage, int, 0644);
+MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
+
+MODULE_AUTHOR("Rafal 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);
Code Review / kvmfornfv.git / blobdiff