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Message-Id: <1311007062-2050-4-git-send-email-mjg@redhat.com>
Date: Mon, 18 Jul 2011 12:37:38 -0400
From: Matthew Garrett <mjg@...hat.com>
To: cpufreq@...r.kernel.org
Cc: davej@...hat.com, linux-kernel@...r.kernel.org,
borislav.petkov@....com, mark.langsdorf@....com,
andreas.herrmann3@....com, Matthew Garrett <mjg@...hat.com>
Subject: [PATCH v4 3/7] acpi-cpufreq: Add support for disabling dynamic overclocking
One feature present in powernow-k8 that isn't present in acpi-cpufreq is
support for enabling or disabling AMD's core performance boost technology.
This patch adds that support to acpi-cpufreq, but also extends it to allow
Intel's dynamic acceleration to be disabled via the same interface. The
sysfs entry retains the cpb name for compatibility purposes.
Signed-off-by: Matthew Garrett <mjg@...hat.com>
---
drivers/cpufreq/acpi-cpufreq.c | 191 ++++++++++++++++++++++++++++++++++++++++
1 files changed, 191 insertions(+), 0 deletions(-)
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 298d451..0a92277 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -76,6 +76,107 @@ static struct acpi_processor_performance __percpu *acpi_perf_data;
static struct cpufreq_driver acpi_cpufreq_driver;
static unsigned int acpi_pstate_strict;
+static bool cpb_enabled, cpb_supported;
+static struct msr __percpu *msrs;
+
+static bool cpb_state(unsigned int cpu)
+{
+ struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
+ u32 lo, hi;
+ u64 msr;
+
+ switch (data->cpu_feature) {
+ case SYSTEM_INTEL_MSR_CAPABLE:
+ rdmsr_on_cpu(cpu, MSR_IA32_MISC_ENABLE, &lo, &hi);
+ msr = lo | ((u64)hi << 32);
+ return !(msr & MSR_IA32_MISC_ENABLE_TURBO_DISABLE);
+ case SYSTEM_AMD_MSR_CAPABLE:
+ rdmsr_on_cpu(cpu, MSR_K7_HWCR, &lo, &hi);
+ msr = lo | ((u64)hi << 32);
+ return !(msr & BIT(25));
+ }
+ return false;
+}
+
+static void _cpb_toggle_msrs(bool enable)
+{
+ struct acpi_cpufreq_data *data = per_cpu(acfreq_data, 0);
+ u32 cpu;
+
+ get_online_cpus();
+
+ switch (data->cpu_feature) {
+ case SYSTEM_INTEL_MSR_CAPABLE:
+ rdmsr_on_cpus(cpu_online_mask, MSR_IA32_MISC_ENABLE, msrs);
+
+ for_each_cpu(cpu, cpu_online_mask) {
+ struct msr *reg = per_cpu_ptr(msrs, cpu);
+ if (enable)
+ reg->q &= ~MSR_IA32_MISC_ENABLE_TURBO_DISABLE;
+ else
+ reg->q |= MSR_IA32_MISC_ENABLE_TURBO_DISABLE;
+ }
+
+ wrmsr_on_cpus(cpu_online_mask, MSR_IA32_MISC_ENABLE, msrs);
+ break;
+ case SYSTEM_AMD_MSR_CAPABLE:
+ rdmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
+
+ for_each_cpu(cpu, cpu_online_mask) {
+ struct msr *reg = per_cpu_ptr(msrs, cpu);
+ if (enable)
+ reg->l &= ~BIT(25);
+ else
+ reg->l |= BIT(25);
+ }
+
+ wrmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
+ break;
+ }
+
+ put_online_cpus();
+}
+
+static void cpb_toggle(bool enable)
+{
+ if (enable && !cpb_enabled) {
+ cpb_enabled = true;
+ _cpb_toggle_msrs(enable);
+ pr_debug("Core Boosting enabled.\n");
+ } else if (!enable && cpb_enabled) {
+ cpb_enabled = false;
+ _cpb_toggle_msrs(enable);
+ pr_debug("Core Boosting disabled.\n");
+ }
+}
+
+static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf,
+ size_t count)
+{
+ int ret = -EINVAL;
+ unsigned long val = 0;
+
+ ret = strict_strtoul(buf, 10, &val);
+ if (!ret && (val == 0 || val == 1) && cpb_supported)
+ cpb_toggle(val);
+ else
+ return -EINVAL;
+
+ return count;
+}
+
+static ssize_t show_cpb(struct cpufreq_policy *policy, char *buf)
+{
+ unsigned int cpu = policy->cpu;
+
+ return sprintf(buf, "%u\n", cpb_state(cpu));
+}
+
+#define define_one_rw(_name) \
+static struct freq_attr _name = \
+ __ATTR(_name, 0644, show_##_name, store_##_name)
+
+define_one_rw(cpb);
static int check_est_cpu(unsigned int cpuid)
{
@@ -446,6 +547,70 @@ static void free_acpi_perf_data(void)
free_percpu(acpi_perf_data);
}
+static int cpb_notify(struct notifier_block *nb, unsigned long action,
+ void *hcpu)
+{
+ unsigned cpu = (long)hcpu;
+ u32 lo, hi;
+ struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
+ int msr;
+ u64 bit;
+
+ switch (data->cpu_feature) {
+ case SYSTEM_INTEL_MSR_CAPABLE:
+ msr = MSR_IA32_MISC_ENABLE;
+ bit = MSR_IA32_MISC_ENABLE_TURBO_DISABLE;
+ break;
+ case SYSTEM_AMD_MSR_CAPABLE:
+ msr = MSR_K7_HWCR;
+ bit = BIT(25);
+ break;
+ default:
+ return NOTIFY_OK;
+ }
+
+ /*
+ * Clear the boost-disable flag on the CPU_DOWN path so that
+ * this cpu cannot block the remaining ones from boosting. On
+ * the CPU_UP path we simply keep the boost-disable flag in
+ * sync with the current global state.
+ */
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ if (!cpb_enabled) {
+ rdmsr_on_cpu(cpu, msr, &lo, &hi);
+ if (bit < BIT(32))
+ lo |= bit;
+ else
+ hi |= (bit >> 32);
+ wrmsr_on_cpu(cpu, msr, lo, hi);
+ }
+ break;
+
+ case CPU_DOWN_PREPARE:
+ case CPU_DOWN_PREPARE_FROZEN:
+ rdmsr_on_cpu(cpu, msr, &lo, &hi);
+ if (bit < BIT(32))
+ lo &= ~bit;
+ else
+ hi &= ~(bit >> 32);
+ wrmsr_on_cpu(cpu, msr, lo, hi);
+ break;
+
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+
+static struct notifier_block cpb_nb = {
+ .notifier_call = cpb_notify,
+};
+
/*
* acpi_cpufreq_early_init - initialize ACPI P-States library
*
@@ -666,6 +831,24 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
if (result)
goto err_freqfree;
+ if (boot_cpu_has(X86_FEATURE_CPB) || boot_cpu_has(X86_FEATURE_IDA)) {
+ msrs = msrs_alloc();
+
+ if (!msrs) {
+ result = -ENOMEM;
+ goto err_freqfree;
+ }
+
+ cpb_supported = true;
+
+ cpb_enabled = cpb_state(0);
+
+ register_cpu_notifier(&cpb_nb);
+
+ /* Make sure all CPUs have the same state */
+ _cpb_toggle_msrs(cpb_enabled);
+ }
+
if (perf->states[0].core_frequency * 1000 != policy->cpuinfo.max_freq)
printk(KERN_WARNING FW_WARN "P-state 0 is not max freq\n");
@@ -749,6 +932,7 @@ static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
static struct freq_attr *acpi_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
+ &cpb,
NULL,
};
@@ -788,6 +972,13 @@ static void __exit acpi_cpufreq_exit(void)
{
pr_debug("acpi_cpufreq_exit\n");
+ if (msrs) {
+ unregister_cpu_notifier(&cpb_nb);
+
+ msrs_free(msrs);
+ msrs = NULL;
+ }
+
cpufreq_unregister_driver(&acpi_cpufreq_driver);
free_acpi_perf_data();
--
1.7.6
--
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