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Diffstat (limited to 'drivers/cpufreq/speedstep-centrino.c')
-rw-r--r--drivers/cpufreq/speedstep-centrino.c561
1 files changed, 561 insertions, 0 deletions
diff --git a/drivers/cpufreq/speedstep-centrino.c b/drivers/cpufreq/speedstep-centrino.c
new file mode 100644
index 0000000000..75b10ecdb6
--- /dev/null
+++ b/drivers/cpufreq/speedstep-centrino.c
@@ -0,0 +1,561 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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 MAINTAINER "linux-pm@vger.kernel.org"
+
+#define INTEL_MSR_RANGE (0xffff)
+
+struct cpu_id
+{
+ __u8 x86; /* CPU family */
+ __u8 x86_model; /* model */
+ __u8 x86_stepping; /* 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_stepping == x->x86_stepping))
+ 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)) {
+ pr_info("couldn't enable Enhanced SpeedStep\n");
+ return -ENODEV;
+ }
+ }
+
+ policy->cpuinfo.transition_latency = 10000;
+ /* 10uS transition latency */
+ policy->freq_table = per_cpu(centrino_model, policy->cpu)->op_points;
+
+ return 0;
+}
+
+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_target - 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_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6, 9, X86_FEATURE_EST, NULL),
+ X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6, 13, X86_FEATURE_EST, NULL),
+ X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 15, 3, X86_FEATURE_EST, NULL),
+ X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 15, 4, X86_FEATURE_EST, NULL),
+ {}
+};
+
+/**
+ * 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(&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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 17:15:38 +0000