diff options
Diffstat (limited to 'drivers/cpufreq/e_powersaver.c')
| -rw-r--r-- | drivers/cpufreq/e_powersaver.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/drivers/cpufreq/e_powersaver.c b/drivers/cpufreq/e_powersaver.c new file mode 100644 index 000000000000..35a257dd4bb7 --- /dev/null +++ b/drivers/cpufreq/e_powersaver.c @@ -0,0 +1,367 @@ +/* + * 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/msr.h> +#include <asm/tsc.h> + +#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; + 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); + +#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 + 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 = 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 (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) + 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_C7M) { + 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->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(0); + + /* 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("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); |