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/*
* 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(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"
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