diff options
Diffstat (limited to 'kernel/drivers/cpufreq/speedstep-centrino.c')
| -rw-r--r-- | kernel/drivers/cpufreq/speedstep-centrino.c | 566 |
1 files changed, 566 insertions, 0 deletions
diff --git a/kernel/drivers/cpufreq/speedstep-centrino.c b/kernel/drivers/cpufreq/speedstep-centrino.c new file mode 100644 index 000000000..7d4a31571 --- /dev/null +++ b/kernel/drivers/cpufreq/speedstep-centrino.c @@ -0,0 +1,566 @@ +/* + * cpufreq driver for Enhanced SpeedStep, as found in Intel's Pentium + * M (part of the Centrino chipset). + * + * Since the original Pentium M, most new Intel CPUs support Enhanced + * SpeedStep. + * + * Despite the "SpeedStep" in the name, this is almost entirely unlike + * traditional SpeedStep. + * + * Modelled on speedstep.c + * + * Copyright (C) 2003 Jeremy Fitzhardinge <jeremy@goop.org> + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/cpufreq.h> +#include <linux/sched.h> /* current */ +#include <linux/delay.h> +#include <linux/compiler.h> +#include <linux/gfp.h> + +#include <asm/msr.h> +#include <asm/processor.h> +#include <asm/cpufeature.h> +#include <asm/cpu_device_id.h> + +#define PFX "speedstep-centrino: " +#define MAINTAINER "linux-pm@vger.kernel.org" + +#define INTEL_MSR_RANGE (0xffff) + +struct cpu_id +{ + __u8 x86; /* CPU family */ + __u8 x86_model; /* model */ + __u8 x86_mask; /* stepping */ +}; + +enum { + CPU_BANIAS, + CPU_DOTHAN_A1, + CPU_DOTHAN_A2, + CPU_DOTHAN_B0, + CPU_MP4HT_D0, + CPU_MP4HT_E0, +}; + +static const struct cpu_id cpu_ids[] = { + [CPU_BANIAS] = { 6, 9, 5 }, + [CPU_DOTHAN_A1] = { 6, 13, 1 }, + [CPU_DOTHAN_A2] = { 6, 13, 2 }, + [CPU_DOTHAN_B0] = { 6, 13, 6 }, + [CPU_MP4HT_D0] = {15, 3, 4 }, + [CPU_MP4HT_E0] = {15, 4, 1 }, +}; +#define N_IDS ARRAY_SIZE(cpu_ids) + +struct cpu_model +{ + const struct cpu_id *cpu_id; + const char *model_name; + unsigned max_freq; /* max clock in kHz */ + + struct cpufreq_frequency_table *op_points; /* clock/voltage pairs */ +}; +static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, + const struct cpu_id *x); + +/* Operating points for current CPU */ +static DEFINE_PER_CPU(struct cpu_model *, centrino_model); +static DEFINE_PER_CPU(const struct cpu_id *, centrino_cpu); + +static struct cpufreq_driver centrino_driver; + +#ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE + +/* Computes the correct form for IA32_PERF_CTL MSR for a particular + frequency/voltage operating point; frequency in MHz, volts in mV. + This is stored as "driver_data" in the structure. */ +#define OP(mhz, mv) \ + { \ + .frequency = (mhz) * 1000, \ + .driver_data = (((mhz)/100) << 8) | ((mv - 700) / 16) \ + } + +/* + * These voltage tables were derived from the Intel Pentium M + * datasheet, document 25261202.pdf, Table 5. I have verified they + * are consistent with my IBM ThinkPad X31, which has a 1.3GHz Pentium + * M. + */ + +/* Ultra Low Voltage Intel Pentium M processor 900MHz (Banias) */ +static struct cpufreq_frequency_table banias_900[] = +{ + OP(600, 844), + OP(800, 988), + OP(900, 1004), + { .frequency = CPUFREQ_TABLE_END } +}; + +/* Ultra Low Voltage Intel Pentium M processor 1000MHz (Banias) */ +static struct cpufreq_frequency_table banias_1000[] = +{ + OP(600, 844), + OP(800, 972), + OP(900, 988), + OP(1000, 1004), + { .frequency = CPUFREQ_TABLE_END } +}; + +/* Low Voltage Intel Pentium M processor 1.10GHz (Banias) */ +static struct cpufreq_frequency_table banias_1100[] = +{ + OP( 600, 956), + OP( 800, 1020), + OP( 900, 1100), + OP(1000, 1164), + OP(1100, 1180), + { .frequency = CPUFREQ_TABLE_END } +}; + + +/* Low Voltage Intel Pentium M processor 1.20GHz (Banias) */ +static struct cpufreq_frequency_table banias_1200[] = +{ + OP( 600, 956), + OP( 800, 1004), + OP( 900, 1020), + OP(1000, 1100), + OP(1100, 1164), + OP(1200, 1180), + { .frequency = CPUFREQ_TABLE_END } +}; + +/* Intel Pentium M processor 1.30GHz (Banias) */ +static struct cpufreq_frequency_table banias_1300[] = +{ + OP( 600, 956), + OP( 800, 1260), + OP(1000, 1292), + OP(1200, 1356), + OP(1300, 1388), + { .frequency = CPUFREQ_TABLE_END } +}; + +/* Intel Pentium M processor 1.40GHz (Banias) */ +static struct cpufreq_frequency_table banias_1400[] = +{ + OP( 600, 956), + OP( 800, 1180), + OP(1000, 1308), + OP(1200, 1436), + OP(1400, 1484), + { .frequency = CPUFREQ_TABLE_END } +}; + +/* Intel Pentium M processor 1.50GHz (Banias) */ +static struct cpufreq_frequency_table banias_1500[] = +{ + OP( 600, 956), + OP( 800, 1116), + OP(1000, 1228), + OP(1200, 1356), + OP(1400, 1452), + OP(1500, 1484), + { .frequency = CPUFREQ_TABLE_END } +}; + +/* Intel Pentium M processor 1.60GHz (Banias) */ +static struct cpufreq_frequency_table banias_1600[] = +{ + OP( 600, 956), + OP( 800, 1036), + OP(1000, 1164), + OP(1200, 1276), + OP(1400, 1420), + OP(1600, 1484), + { .frequency = CPUFREQ_TABLE_END } +}; + +/* Intel Pentium M processor 1.70GHz (Banias) */ +static struct cpufreq_frequency_table banias_1700[] = +{ + OP( 600, 956), + OP( 800, 1004), + OP(1000, 1116), + OP(1200, 1228), + OP(1400, 1308), + OP(1700, 1484), + { .frequency = CPUFREQ_TABLE_END } +}; +#undef OP + +#define _BANIAS(cpuid, max, name) \ +{ .cpu_id = cpuid, \ + .model_name = "Intel(R) Pentium(R) M processor " name "MHz", \ + .max_freq = (max)*1000, \ + .op_points = banias_##max, \ +} +#define BANIAS(max) _BANIAS(&cpu_ids[CPU_BANIAS], max, #max) + +/* CPU models, their operating frequency range, and freq/voltage + operating points */ +static struct cpu_model models[] = +{ + _BANIAS(&cpu_ids[CPU_BANIAS], 900, " 900"), + BANIAS(1000), + BANIAS(1100), + BANIAS(1200), + BANIAS(1300), + BANIAS(1400), + BANIAS(1500), + BANIAS(1600), + BANIAS(1700), + + /* NULL model_name is a wildcard */ + { &cpu_ids[CPU_DOTHAN_A1], NULL, 0, NULL }, + { &cpu_ids[CPU_DOTHAN_A2], NULL, 0, NULL }, + { &cpu_ids[CPU_DOTHAN_B0], NULL, 0, NULL }, + { &cpu_ids[CPU_MP4HT_D0], NULL, 0, NULL }, + { &cpu_ids[CPU_MP4HT_E0], NULL, 0, NULL }, + + { NULL, } +}; +#undef _BANIAS +#undef BANIAS + +static int centrino_cpu_init_table(struct cpufreq_policy *policy) +{ + struct cpuinfo_x86 *cpu = &cpu_data(policy->cpu); + struct cpu_model *model; + + for(model = models; model->cpu_id != NULL; model++) + if (centrino_verify_cpu_id(cpu, model->cpu_id) && + (model->model_name == NULL || + strcmp(cpu->x86_model_id, model->model_name) == 0)) + break; + + if (model->cpu_id == NULL) { + /* No match at all */ + pr_debug("no support for CPU model \"%s\": " + "send /proc/cpuinfo to " MAINTAINER "\n", + cpu->x86_model_id); + return -ENOENT; + } + + if (model->op_points == NULL) { + /* Matched a non-match */ + pr_debug("no table support for CPU model \"%s\"\n", + cpu->x86_model_id); + pr_debug("try using the acpi-cpufreq driver\n"); + return -ENOENT; + } + + per_cpu(centrino_model, policy->cpu) = model; + + pr_debug("found \"%s\": max frequency: %dkHz\n", + model->model_name, model->max_freq); + + return 0; +} + +#else +static inline int centrino_cpu_init_table(struct cpufreq_policy *policy) +{ + return -ENODEV; +} +#endif /* CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE */ + +static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, + const struct cpu_id *x) +{ + if ((c->x86 == x->x86) && + (c->x86_model == x->x86_model) && + (c->x86_mask == x->x86_mask)) + return 1; + return 0; +} + +/* To be called only after centrino_model is initialized */ +static unsigned extract_clock(unsigned msr, unsigned int cpu, int failsafe) +{ + int i; + + /* + * Extract clock in kHz from PERF_CTL value + * for centrino, as some DSDTs are buggy. + * Ideally, this can be done using the acpi_data structure. + */ + if ((per_cpu(centrino_cpu, cpu) == &cpu_ids[CPU_BANIAS]) || + (per_cpu(centrino_cpu, cpu) == &cpu_ids[CPU_DOTHAN_A1]) || + (per_cpu(centrino_cpu, cpu) == &cpu_ids[CPU_DOTHAN_B0])) { + msr = (msr >> 8) & 0xff; + return msr * 100000; + } + + if ((!per_cpu(centrino_model, cpu)) || + (!per_cpu(centrino_model, cpu)->op_points)) + return 0; + + msr &= 0xffff; + for (i = 0; + per_cpu(centrino_model, cpu)->op_points[i].frequency + != CPUFREQ_TABLE_END; + i++) { + if (msr == per_cpu(centrino_model, cpu)->op_points[i].driver_data) + return per_cpu(centrino_model, cpu)-> + op_points[i].frequency; + } + if (failsafe) + return per_cpu(centrino_model, cpu)->op_points[i-1].frequency; + else + return 0; +} + +/* Return the current CPU frequency in kHz */ +static unsigned int get_cur_freq(unsigned int cpu) +{ + unsigned l, h; + unsigned clock_freq; + + rdmsr_on_cpu(cpu, MSR_IA32_PERF_STATUS, &l, &h); + clock_freq = extract_clock(l, cpu, 0); + + if (unlikely(clock_freq == 0)) { + /* + * On some CPUs, we can see transient MSR values (which are + * not present in _PSS), while CPU is doing some automatic + * P-state transition (like TM2). Get the last freq set + * in PERF_CTL. + */ + rdmsr_on_cpu(cpu, MSR_IA32_PERF_CTL, &l, &h); + clock_freq = extract_clock(l, cpu, 1); + } + return clock_freq; +} + + +static int centrino_cpu_init(struct cpufreq_policy *policy) +{ + struct cpuinfo_x86 *cpu = &cpu_data(policy->cpu); + unsigned l, h; + int i; + + /* Only Intel makes Enhanced Speedstep-capable CPUs */ + if (cpu->x86_vendor != X86_VENDOR_INTEL || + !cpu_has(cpu, X86_FEATURE_EST)) + return -ENODEV; + + if (cpu_has(cpu, X86_FEATURE_CONSTANT_TSC)) + centrino_driver.flags |= CPUFREQ_CONST_LOOPS; + + if (policy->cpu != 0) + return -ENODEV; + + for (i = 0; i < N_IDS; i++) + if (centrino_verify_cpu_id(cpu, &cpu_ids[i])) + break; + + if (i != N_IDS) + per_cpu(centrino_cpu, policy->cpu) = &cpu_ids[i]; + + if (!per_cpu(centrino_cpu, policy->cpu)) { + pr_debug("found unsupported CPU with " + "Enhanced SpeedStep: send /proc/cpuinfo to " + MAINTAINER "\n"); + return -ENODEV; + } + + if (centrino_cpu_init_table(policy)) + return -ENODEV; + + /* Check to see if Enhanced SpeedStep is enabled, and try to + enable it if not. */ + rdmsr(MSR_IA32_MISC_ENABLE, l, h); + + if (!(l & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { + l |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP; + pr_debug("trying to enable Enhanced SpeedStep (%x)\n", l); + wrmsr(MSR_IA32_MISC_ENABLE, l, h); + + /* check to see if it stuck */ + rdmsr(MSR_IA32_MISC_ENABLE, l, h); + if (!(l & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { + printk(KERN_INFO PFX + "couldn't enable Enhanced SpeedStep\n"); + return -ENODEV; + } + } + + policy->cpuinfo.transition_latency = 10000; + /* 10uS transition latency */ + + return cpufreq_table_validate_and_show(policy, + per_cpu(centrino_model, policy->cpu)->op_points); +} + +static int centrino_cpu_exit(struct cpufreq_policy *policy) +{ + unsigned int cpu = policy->cpu; + + if (!per_cpu(centrino_model, cpu)) + return -ENODEV; + + per_cpu(centrino_model, cpu) = NULL; + + return 0; +} + +/** + * centrino_setpolicy - set a new CPUFreq policy + * @policy: new policy + * @index: index of target frequency + * + * Sets a new CPUFreq policy. + */ +static int centrino_target(struct cpufreq_policy *policy, unsigned int index) +{ + unsigned int msr, oldmsr = 0, h = 0, cpu = policy->cpu; + int retval = 0; + unsigned int j, first_cpu; + struct cpufreq_frequency_table *op_points; + cpumask_var_t covered_cpus; + + if (unlikely(!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))) + return -ENOMEM; + + if (unlikely(per_cpu(centrino_model, cpu) == NULL)) { + retval = -ENODEV; + goto out; + } + + first_cpu = 1; + op_points = &per_cpu(centrino_model, cpu)->op_points[index]; + for_each_cpu(j, policy->cpus) { + int good_cpu; + + /* + * Support for SMP systems. + * Make sure we are running on CPU that wants to change freq + */ + if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) + good_cpu = cpumask_any_and(policy->cpus, + cpu_online_mask); + else + good_cpu = j; + + if (good_cpu >= nr_cpu_ids) { + pr_debug("couldn't limit to CPUs in this domain\n"); + retval = -EAGAIN; + if (first_cpu) { + /* We haven't started the transition yet. */ + goto out; + } + break; + } + + msr = op_points->driver_data; + + if (first_cpu) { + rdmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, &oldmsr, &h); + if (msr == (oldmsr & 0xffff)) { + pr_debug("no change needed - msr was and needs " + "to be %x\n", oldmsr); + retval = 0; + goto out; + } + + first_cpu = 0; + /* all but 16 LSB are reserved, treat them with care */ + oldmsr &= ~0xffff; + msr &= 0xffff; + oldmsr |= msr; + } + + wrmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, oldmsr, h); + if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) + break; + + cpumask_set_cpu(j, covered_cpus); + } + + if (unlikely(retval)) { + /* + * We have failed halfway through the frequency change. + * We have sent callbacks to policy->cpus and + * MSRs have already been written on coverd_cpus. + * Best effort undo.. + */ + + for_each_cpu(j, covered_cpus) + wrmsr_on_cpu(j, MSR_IA32_PERF_CTL, oldmsr, h); + } + retval = 0; + +out: + free_cpumask_var(covered_cpus); + return retval; +} + +static struct cpufreq_driver centrino_driver = { + .name = "centrino", /* should be speedstep-centrino, + but there's a 16 char limit */ + .init = centrino_cpu_init, + .exit = centrino_cpu_exit, + .verify = cpufreq_generic_frequency_table_verify, + .target_index = centrino_target, + .get = get_cur_freq, + .attr = cpufreq_generic_attr, +}; + +/* + * This doesn't replace the detailed checks above because + * the generic CPU IDs don't have a way to match for steppings + * or ASCII model IDs. + */ +static const struct x86_cpu_id centrino_ids[] = { + { X86_VENDOR_INTEL, 6, 9, X86_FEATURE_EST }, + { X86_VENDOR_INTEL, 6, 13, X86_FEATURE_EST }, + { X86_VENDOR_INTEL, 6, 13, X86_FEATURE_EST }, + { X86_VENDOR_INTEL, 6, 13, X86_FEATURE_EST }, + { X86_VENDOR_INTEL, 15, 3, X86_FEATURE_EST }, + { X86_VENDOR_INTEL, 15, 4, X86_FEATURE_EST }, + {} +}; +#if 0 +/* Autoload or not? Do not for now. */ +MODULE_DEVICE_TABLE(x86cpu, centrino_ids); +#endif + +/** + * centrino_init - initializes the Enhanced SpeedStep CPUFreq driver + * + * Initializes the Enhanced SpeedStep support. Returns -ENODEV on + * unsupported devices, -ENOENT if there's no voltage table for this + * particular CPU model, -EINVAL on problems during initiatization, + * and zero on success. + * + * This is quite picky. Not only does the CPU have to advertise the + * "est" flag in the cpuid capability flags, we look for a specific + * CPU model and stepping, and we need to have the exact model name in + * our voltage tables. That is, be paranoid about not releasing + * someone's valuable magic smoke. + */ +static int __init centrino_init(void) +{ + if (!x86_match_cpu(centrino_ids)) + return -ENODEV; + return cpufreq_register_driver(¢rino_driver); +} + +static void __exit centrino_exit(void) +{ + cpufreq_unregister_driver(¢rino_driver); +} + +MODULE_AUTHOR ("Jeremy Fitzhardinge <jeremy@goop.org>"); +MODULE_DESCRIPTION ("Enhanced SpeedStep driver for Intel Pentium M processors."); +MODULE_LICENSE ("GPL"); + +late_initcall(centrino_init); +module_exit(centrino_exit); |