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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c')
-rw-r--r--arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c715
1 files changed, 715 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c b/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
new file mode 100644
index 00000000000..07d5612dc00
--- /dev/null
+++ b/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
@@ -0,0 +1,715 @@
+/*
+ * cpufreq driver for Enhanced SpeedStep, as found in Intel's Pentium
+ * M (part of the Centrino chipset).
+ *
+ * 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>
+ *
+ * WARNING WARNING WARNING
+ *
+ * This driver manipulates the PERF_CTL MSR, which is only somewhat
+ * documented. While it seems to work on my laptop, it has not been
+ * tested anywhere else, and it may not work for you, do strange
+ * things or simply crash.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/config.h>
+#include <linux/delay.h>
+#include <linux/compiler.h>
+
+#ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI
+#include <linux/acpi.h>
+#include <acpi/processor.h>
+#endif
+
+#include <asm/msr.h>
+#include <asm/processor.h>
+#include <asm/cpufeature.h>
+
+#include "speedstep-est-common.h"
+
+#define PFX "speedstep-centrino: "
+#define MAINTAINER "Jeremy Fitzhardinge <jeremy@goop.org>"
+
+#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "speedstep-centrino", msg)
+
+
+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,
+};
+
+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 },
+};
+#define N_IDS (sizeof(cpu_ids)/sizeof(cpu_ids[0]))
+
+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 struct cpu_model *centrino_model[NR_CPUS];
+static const struct cpu_id *centrino_cpu[NR_CPUS];
+
+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 "index" in the structure. */
+#define OP(mhz, mv) \
+ { \
+ .frequency = (mhz) * 1000, \
+ .index = (((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 },
+
+ { 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 */
+ dprintk(KERN_INFO PFX "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 */
+ dprintk(KERN_INFO PFX "no table support for CPU model \"%s\": \n",
+ cpu->x86_model_id);
+#ifndef CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI
+ dprintk(KERN_INFO PFX "try compiling with CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI enabled\n");
+#endif
+ return -ENOENT;
+ }
+
+ centrino_model[policy->cpu] = model;
+
+ dprintk("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 ((centrino_cpu[cpu] == &cpu_ids[CPU_BANIAS]) ||
+ (centrino_cpu[cpu] == &cpu_ids[CPU_DOTHAN_A1]) ||
+ (centrino_cpu[cpu] == &cpu_ids[CPU_DOTHAN_B0])) {
+ msr = (msr >> 8) & 0xff;
+ return msr * 100000;
+ }
+
+ if ((!centrino_model[cpu]) || (!centrino_model[cpu]->op_points))
+ return 0;
+
+ msr &= 0xffff;
+ for (i=0;centrino_model[cpu]->op_points[i].frequency != CPUFREQ_TABLE_END; i++) {
+ if (msr == centrino_model[cpu]->op_points[i].index)
+ return centrino_model[cpu]->op_points[i].frequency;
+ }
+ if (failsafe)
+ return 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;
+ cpumask_t saved_mask;
+
+ saved_mask = current->cpus_allowed;
+ set_cpus_allowed(current, cpumask_of_cpu(cpu));
+ if (smp_processor_id() != cpu)
+ return 0;
+
+ rdmsr(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(MSR_IA32_PERF_CTL, l, h);
+ clock_freq = extract_clock(l, cpu, 1);
+ }
+
+ set_cpus_allowed(current, saved_mask);
+ return clock_freq;
+}
+
+
+#ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI
+
+static struct acpi_processor_performance p;
+
+/*
+ * centrino_cpu_init_acpi - register with ACPI P-States library
+ *
+ * Register with the ACPI P-States library (part of drivers/acpi/processor.c)
+ * in order to determine correct frequency and voltage pairings by reading
+ * the _PSS of the ACPI DSDT or SSDT tables.
+ */
+static int centrino_cpu_init_acpi(struct cpufreq_policy *policy)
+{
+ union acpi_object arg0 = {ACPI_TYPE_BUFFER};
+ u32 arg0_buf[3];
+ struct acpi_object_list arg_list = {1, &arg0};
+ unsigned long cur_freq;
+ int result = 0, i;
+ unsigned int cpu = policy->cpu;
+
+ /* _PDC settings */
+ arg0.buffer.length = 12;
+ arg0.buffer.pointer = (u8 *) arg0_buf;
+ arg0_buf[0] = ACPI_PDC_REVISION_ID;
+ arg0_buf[1] = 1;
+ arg0_buf[2] = ACPI_PDC_EST_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_MSR;
+
+ p.pdc = &arg_list;
+
+ /* register with ACPI core */
+ if (acpi_processor_register_performance(&p, cpu)) {
+ dprintk(KERN_INFO PFX "obtaining ACPI data failed\n");
+ return -EIO;
+ }
+
+ /* verify the acpi_data */
+ if (p.state_count <= 1) {
+ dprintk("No P-States\n");
+ result = -ENODEV;
+ goto err_unreg;
+ }
+
+ if ((p.control_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) ||
+ (p.status_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) {
+ dprintk("Invalid control/status registers (%x - %x)\n",
+ p.control_register.space_id, p.status_register.space_id);
+ result = -EIO;
+ goto err_unreg;
+ }
+
+ for (i=0; i<p.state_count; i++) {
+ if (p.states[i].control != p.states[i].status) {
+ dprintk("Different control (%x) and status values (%x)\n",
+ p.states[i].control, p.states[i].status);
+ result = -EINVAL;
+ goto err_unreg;
+ }
+
+ if (!p.states[i].core_frequency) {
+ dprintk("Zero core frequency for state %u\n", i);
+ result = -EINVAL;
+ goto err_unreg;
+ }
+
+ if (p.states[i].core_frequency > p.states[0].core_frequency) {
+ dprintk("P%u has larger frequency (%u) than P0 (%u), skipping\n", i,
+ p.states[i].core_frequency, p.states[0].core_frequency);
+ p.states[i].core_frequency = 0;
+ continue;
+ }
+ }
+
+ centrino_model[cpu] = kmalloc(sizeof(struct cpu_model), GFP_KERNEL);
+ if (!centrino_model[cpu]) {
+ result = -ENOMEM;
+ goto err_unreg;
+ }
+ memset(centrino_model[cpu], 0, sizeof(struct cpu_model));
+
+ centrino_model[cpu]->model_name=NULL;
+ centrino_model[cpu]->max_freq = p.states[0].core_frequency * 1000;
+ centrino_model[cpu]->op_points = kmalloc(sizeof(struct cpufreq_frequency_table) *
+ (p.state_count + 1), GFP_KERNEL);
+ if (!centrino_model[cpu]->op_points) {
+ result = -ENOMEM;
+ goto err_kfree;
+ }
+
+ for (i=0; i<p.state_count; i++) {
+ centrino_model[cpu]->op_points[i].index = p.states[i].control;
+ centrino_model[cpu]->op_points[i].frequency = p.states[i].core_frequency * 1000;
+ dprintk("adding state %i with frequency %u and control value %04x\n",
+ i, centrino_model[cpu]->op_points[i].frequency, centrino_model[cpu]->op_points[i].index);
+ }
+ centrino_model[cpu]->op_points[p.state_count].frequency = CPUFREQ_TABLE_END;
+
+ cur_freq = get_cur_freq(cpu);
+
+ for (i=0; i<p.state_count; i++) {
+ if (!p.states[i].core_frequency) {
+ dprintk("skipping state %u\n", i);
+ centrino_model[cpu]->op_points[i].frequency = CPUFREQ_ENTRY_INVALID;
+ continue;
+ }
+
+ if (extract_clock(centrino_model[cpu]->op_points[i].index, cpu, 0) !=
+ (centrino_model[cpu]->op_points[i].frequency)) {
+ dprintk("Invalid encoded frequency (%u vs. %u)\n",
+ extract_clock(centrino_model[cpu]->op_points[i].index, cpu, 0),
+ centrino_model[cpu]->op_points[i].frequency);
+ result = -EINVAL;
+ goto err_kfree_all;
+ }
+
+ if (cur_freq == centrino_model[cpu]->op_points[i].frequency)
+ p.state = i;
+ }
+
+ /* notify BIOS that we exist */
+ acpi_processor_notify_smm(THIS_MODULE);
+
+ return 0;
+
+ err_kfree_all:
+ kfree(centrino_model[cpu]->op_points);
+ err_kfree:
+ kfree(centrino_model[cpu]);
+ err_unreg:
+ acpi_processor_unregister_performance(&p, cpu);
+ dprintk(KERN_INFO PFX "invalid ACPI data\n");
+ return (result);
+}
+#else
+static inline int centrino_cpu_init_acpi(struct cpufreq_policy *policy) { return -ENODEV; }
+#endif
+
+static int centrino_cpu_init(struct cpufreq_policy *policy)
+{
+ struct cpuinfo_x86 *cpu = &cpu_data[policy->cpu];
+ unsigned freq;
+ unsigned l, h;
+ int ret;
+ int i;
+
+ /* Only Intel makes Enhanced Speedstep-capable CPUs */
+ if (cpu->x86_vendor != X86_VENDOR_INTEL || !cpu_has(cpu, X86_FEATURE_EST))
+ return -ENODEV;
+
+ for (i = 0; i < N_IDS; i++)
+ if (centrino_verify_cpu_id(cpu, &cpu_ids[i]))
+ break;
+
+ if (i != N_IDS)
+ centrino_cpu[policy->cpu] = &cpu_ids[i];
+
+ if (is_const_loops_cpu(policy->cpu)) {
+ centrino_driver.flags |= CPUFREQ_CONST_LOOPS;
+ }
+
+ if (centrino_cpu_init_acpi(policy)) {
+ if (policy->cpu != 0)
+ return -ENODEV;
+
+ if (!centrino_cpu[policy->cpu]) {
+ dprintk(KERN_INFO PFX "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 & (1<<16))) {
+ l |= (1<<16);
+ dprintk("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 & (1<<16))) {
+ printk(KERN_INFO PFX "couldn't enable Enhanced SpeedStep\n");
+ return -ENODEV;
+ }
+ }
+
+ freq = get_cur_freq(policy->cpu);
+
+ policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+ policy->cpuinfo.transition_latency = 10000; /* 10uS transition latency */
+ policy->cur = freq;
+
+ dprintk("centrino_cpu_init: cur=%dkHz\n", policy->cur);
+
+ ret = cpufreq_frequency_table_cpuinfo(policy, centrino_model[policy->cpu]->op_points);
+ if (ret)
+ return (ret);
+
+ cpufreq_frequency_table_get_attr(centrino_model[policy->cpu]->op_points, policy->cpu);
+
+ return 0;
+}
+
+static int centrino_cpu_exit(struct cpufreq_policy *policy)
+{
+ unsigned int cpu = policy->cpu;
+
+ if (!centrino_model[cpu])
+ return -ENODEV;
+
+ cpufreq_frequency_table_put_attr(cpu);
+
+#ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI
+ if (!centrino_model[cpu]->model_name) {
+ dprintk("unregistering and freeing ACPI data\n");
+ acpi_processor_unregister_performance(&p, cpu);
+ kfree(centrino_model[cpu]->op_points);
+ kfree(centrino_model[cpu]);
+ }
+#endif
+
+ centrino_model[cpu] = NULL;
+
+ return 0;
+}
+
+/**
+ * centrino_verify - verifies a new CPUFreq policy
+ * @policy: new policy
+ *
+ * Limit must be within this model's frequency range at least one
+ * border included.
+ */
+static int centrino_verify (struct cpufreq_policy *policy)
+{
+ return cpufreq_frequency_table_verify(policy, centrino_model[policy->cpu]->op_points);
+}
+
+/**
+ * centrino_setpolicy - set a new CPUFreq policy
+ * @policy: new policy
+ * @target_freq: the target frequency
+ * @relation: how that frequency relates to achieved frequency (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
+ *
+ * Sets a new CPUFreq policy.
+ */
+static int centrino_target (struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ unsigned int newstate = 0;
+ unsigned int msr, oldmsr, h, cpu = policy->cpu;
+ struct cpufreq_freqs freqs;
+ cpumask_t saved_mask;
+ int retval;
+
+ if (centrino_model[cpu] == NULL)
+ return -ENODEV;
+
+ /*
+ * Support for SMP systems.
+ * Make sure we are running on the CPU that wants to change frequency
+ */
+ saved_mask = current->cpus_allowed;
+ set_cpus_allowed(current, policy->cpus);
+ if (!cpu_isset(smp_processor_id(), policy->cpus)) {
+ dprintk("couldn't limit to CPUs in this domain\n");
+ return(-EAGAIN);
+ }
+
+ if (cpufreq_frequency_table_target(policy, centrino_model[cpu]->op_points, target_freq,
+ relation, &newstate)) {
+ retval = -EINVAL;
+ goto migrate_end;
+ }
+
+ msr = centrino_model[cpu]->op_points[newstate].index;
+ rdmsr(MSR_IA32_PERF_CTL, oldmsr, h);
+
+ if (msr == (oldmsr & 0xffff)) {
+ retval = 0;
+ dprintk("no change needed - msr was and needs to be %x\n", oldmsr);
+ goto migrate_end;
+ }
+
+ freqs.cpu = cpu;
+ freqs.old = extract_clock(oldmsr, cpu, 0);
+ freqs.new = extract_clock(msr, cpu, 0);
+
+ dprintk("target=%dkHz old=%d new=%d msr=%04x\n",
+ target_freq, freqs.old, freqs.new, msr);
+
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+ /* all but 16 LSB are "reserved", so treat them with
+ care */
+ oldmsr &= ~0xffff;
+ msr &= 0xffff;
+ oldmsr |= msr;
+
+ wrmsr(MSR_IA32_PERF_CTL, oldmsr, h);
+
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+ retval = 0;
+migrate_end:
+ set_cpus_allowed(current, saved_mask);
+ return (retval);
+}
+
+static struct freq_attr* centrino_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL,
+};
+
+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 = centrino_verify,
+ .target = centrino_target,
+ .get = get_cur_freq,
+ .attr = centrino_attr,
+ .owner = THIS_MODULE,
+};
+
+
+/**
+ * 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)
+{
+ struct cpuinfo_x86 *cpu = cpu_data;
+
+ if (!cpu_has(cpu, X86_FEATURE_EST))
+ return -ENODEV;
+
+ return cpufreq_register_driver(&centrino_driver);
+}
+
+static void __exit centrino_exit(void)
+{
+ cpufreq_unregister_driver(&centrino_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);