blob: 82d370ae6a4a5c045a27eeee05289fd6246e6b60 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* CPPC (Collaborative Processor Performance Control) driver for
* interfacing with the CPUfreq layer and governors. See
* cppc_acpi.c for CPPC specific methods.
*
* (C) Copyright 2014, 2015 Linaro Ltd.
* Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
*/
#define pr_fmt(fmt) "CPPC Cpufreq:" fmt
#include <linux/arch_topology.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/dmi.h>
#include <linux/irq_work.h>
#include <linux/kthread.h>
#include <linux/time.h>
#include <linux/vmalloc.h>
#include <uapi/linux/sched/types.h>
#include <asm/unaligned.h>
#include <acpi/cppc_acpi.h>
/* Minimum struct length needed for the DMI processor entry we want */
#define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48
/* Offset in the DMI processor structure for the max frequency */
#define DMI_PROCESSOR_MAX_SPEED 0x14
/*
* This list contains information parsed from per CPU ACPI _CPC and _PSD
* structures: e.g. the highest and lowest supported performance, capabilities,
* desired performance, level requested etc. Depending on the share_type, not
* all CPUs will have an entry in the list.
*/
static LIST_HEAD(cpu_data_list);
static bool boost_supported;
struct cppc_workaround_oem_info {
char oem_id[ACPI_OEM_ID_SIZE + 1];
char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
u32 oem_revision;
};
static struct cppc_workaround_oem_info wa_info[] = {
{
.oem_id = "HISI ",
.oem_table_id = "HIP07 ",
.oem_revision = 0,
}, {
.oem_id = "HISI ",
.oem_table_id = "HIP08 ",
.oem_revision = 0,
}
};
#ifdef CONFIG_ACPI_CPPC_CPUFREQ_FIE
/* Frequency invariance support */
struct cppc_freq_invariance {
int cpu;
struct irq_work irq_work;
struct kthread_work work;
struct cppc_perf_fb_ctrs prev_perf_fb_ctrs;
struct cppc_cpudata *cpu_data;
};
static DEFINE_PER_CPU(struct cppc_freq_invariance, cppc_freq_inv);
static struct kthread_worker *kworker_fie;
static struct cpufreq_driver cppc_cpufreq_driver;
static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpu);
static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data,
struct cppc_perf_fb_ctrs *fb_ctrs_t0,
struct cppc_perf_fb_ctrs *fb_ctrs_t1);
/**
* cppc_scale_freq_workfn - CPPC arch_freq_scale updater for frequency invariance
* @work: The work item.
*
* The CPPC driver register itself with the topology core to provide its own
* implementation (cppc_scale_freq_tick()) of topology_scale_freq_tick() which
* gets called by the scheduler on every tick.
*
* Note that the arch specific counters have higher priority than CPPC counters,
* if available, though the CPPC driver doesn't need to have any special
* handling for that.
*
* On an invocation of cppc_scale_freq_tick(), we schedule an irq work (since we
* reach here from hard-irq context), which then schedules a normal work item
* and cppc_scale_freq_workfn() updates the per_cpu arch_freq_scale variable
* based on the counter updates since the last tick.
*/
static void cppc_scale_freq_workfn(struct kthread_work *work)
{
struct cppc_freq_invariance *cppc_fi;
struct cppc_perf_fb_ctrs fb_ctrs = {0};
struct cppc_cpudata *cpu_data;
unsigned long local_freq_scale;
u64 perf;
cppc_fi = container_of(work, struct cppc_freq_invariance, work);
cpu_data = cppc_fi->cpu_data;
if (cppc_get_perf_ctrs(cppc_fi->cpu, &fb_ctrs)) {
pr_warn("%s: failed to read perf counters\n", __func__);
return;
}
perf = cppc_perf_from_fbctrs(cpu_data, &cppc_fi->prev_perf_fb_ctrs,
&fb_ctrs);
cppc_fi->prev_perf_fb_ctrs = fb_ctrs;
perf <<= SCHED_CAPACITY_SHIFT;
local_freq_scale = div64_u64(perf, cpu_data->perf_caps.highest_perf);
/* This can happen due to counter's overflow */
if (unlikely(local_freq_scale > 1024))
local_freq_scale = 1024;
per_cpu(arch_freq_scale, cppc_fi->cpu) = local_freq_scale;
}
static void cppc_irq_work(struct irq_work *irq_work)
{
struct cppc_freq_invariance *cppc_fi;
cppc_fi = container_of(irq_work, struct cppc_freq_invariance, irq_work);
kthread_queue_work(kworker_fie, &cppc_fi->work);
}
static void cppc_scale_freq_tick(void)
{
struct cppc_freq_invariance *cppc_fi = &per_cpu(cppc_freq_inv, smp_processor_id());
/*
* cppc_get_perf_ctrs() can potentially sleep, call that from the right
* context.
*/
irq_work_queue(&cppc_fi->irq_work);
}
static struct scale_freq_data cppc_sftd = {
.source = SCALE_FREQ_SOURCE_CPPC,
.set_freq_scale = cppc_scale_freq_tick,
};
static void cppc_cpufreq_cpu_fie_init(struct cpufreq_policy *policy)
{
struct cppc_freq_invariance *cppc_fi;
int cpu, ret;
if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
return;
for_each_cpu(cpu, policy->cpus) {
cppc_fi = &per_cpu(cppc_freq_inv, cpu);
cppc_fi->cpu = cpu;
cppc_fi->cpu_data = policy->driver_data;
kthread_init_work(&cppc_fi->work, cppc_scale_freq_workfn);
init_irq_work(&cppc_fi->irq_work, cppc_irq_work);
ret = cppc_get_perf_ctrs(cpu, &cppc_fi->prev_perf_fb_ctrs);
if (ret) {
pr_warn("%s: failed to read perf counters for cpu:%d: %d\n",
__func__, cpu, ret);
/*
* Don't abort if the CPU was offline while the driver
* was getting registered.
*/
if (cpu_online(cpu))
return;
}
}
/* Register for freq-invariance */
topology_set_scale_freq_source(&cppc_sftd, policy->cpus);
}
/*
* We free all the resources on policy's removal and not on CPU removal as the
* irq-work are per-cpu and the hotplug core takes care of flushing the pending
* irq-works (hint: smpcfd_dying_cpu()) on CPU hotplug. Even if the kthread-work
* fires on another CPU after the concerned CPU is removed, it won't harm.
*
* We just need to make sure to remove them all on policy->exit().
*/
static void cppc_cpufreq_cpu_fie_exit(struct cpufreq_policy *policy)
{
struct cppc_freq_invariance *cppc_fi;
int cpu;
if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
return;
/* policy->cpus will be empty here, use related_cpus instead */
topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_CPPC, policy->related_cpus);
for_each_cpu(cpu, policy->related_cpus) {
cppc_fi = &per_cpu(cppc_freq_inv, cpu);
irq_work_sync(&cppc_fi->irq_work);
kthread_cancel_work_sync(&cppc_fi->work);
}
}
static void __init cppc_freq_invariance_init(void)
{
struct sched_attr attr = {
.size = sizeof(struct sched_attr),
.sched_policy = SCHED_DEADLINE,
.sched_nice = 0,
.sched_priority = 0,
/*
* Fake (unused) bandwidth; workaround to "fix"
* priority inheritance.
*/
.sched_runtime = 1000000,
.sched_deadline = 10000000,
.sched_period = 10000000,
};
int ret;
if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
return;
kworker_fie = kthread_create_worker(0, "cppc_fie");
if (IS_ERR(kworker_fie))
return;
ret = sched_setattr_nocheck(kworker_fie->task, &attr);
if (ret) {
pr_warn("%s: failed to set SCHED_DEADLINE: %d\n", __func__,
ret);
kthread_destroy_worker(kworker_fie);
return;
}
}
static void cppc_freq_invariance_exit(void)
{
if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
return;
kthread_destroy_worker(kworker_fie);
kworker_fie = NULL;
}
#else
static inline void cppc_cpufreq_cpu_fie_init(struct cpufreq_policy *policy)
{
}
static inline void cppc_cpufreq_cpu_fie_exit(struct cpufreq_policy *policy)
{
}
static inline void cppc_freq_invariance_init(void)
{
}
static inline void cppc_freq_invariance_exit(void)
{
}
#endif /* CONFIG_ACPI_CPPC_CPUFREQ_FIE */
/* Callback function used to retrieve the max frequency from DMI */
static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
{
const u8 *dmi_data = (const u8 *)dm;
u16 *mhz = (u16 *)private;
if (dm->type == DMI_ENTRY_PROCESSOR &&
dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
u16 val = (u16)get_unaligned((const u16 *)
(dmi_data + DMI_PROCESSOR_MAX_SPEED));
*mhz = val > *mhz ? val : *mhz;
}
}
/* Look up the max frequency in DMI */
static u64 cppc_get_dmi_max_khz(void)
{
u16 mhz = 0;
dmi_walk(cppc_find_dmi_mhz, &mhz);
/*
* Real stupid fallback value, just in case there is no
* actual value set.
*/
mhz = mhz ? mhz : 1;
return (1000 * mhz);
}
/*
* If CPPC lowest_freq and nominal_freq registers are exposed then we can
* use them to convert perf to freq and vice versa. The conversion is
* extrapolated as an affine function passing by the 2 points:
* - (Low perf, Low freq)
* - (Nominal perf, Nominal perf)
*/
static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu_data,
unsigned int perf)
{
struct cppc_perf_caps *caps = &cpu_data->perf_caps;
s64 retval, offset = 0;
static u64 max_khz;
u64 mul, div;
if (caps->lowest_freq && caps->nominal_freq) {
mul = caps->nominal_freq - caps->lowest_freq;
div = caps->nominal_perf - caps->lowest_perf;
offset = caps->nominal_freq - div64_u64(caps->nominal_perf * mul, div);
} else {
if (!max_khz)
max_khz = cppc_get_dmi_max_khz();
mul = max_khz;
div = caps->highest_perf;
}
retval = offset + div64_u64(perf * mul, div);
if (retval >= 0)
return retval;
return 0;
}
static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu_data,
unsigned int freq)
{
struct cppc_perf_caps *caps = &cpu_data->perf_caps;
s64 retval, offset = 0;
static u64 max_khz;
u64 mul, div;
if (caps->lowest_freq && caps->nominal_freq) {
mul = caps->nominal_perf - caps->lowest_perf;
div = caps->nominal_freq - caps->lowest_freq;
offset = caps->nominal_perf - div64_u64(caps->nominal_freq * mul, div);
} else {
if (!max_khz)
max_khz = cppc_get_dmi_max_khz();
mul = caps->highest_perf;
div = max_khz;
}
retval = offset + div64_u64(freq * mul, div);
if (retval >= 0)
return retval;
return 0;
}
static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
unsigned int cpu = policy->cpu;
struct cpufreq_freqs freqs;
u32 desired_perf;
int ret = 0;
desired_perf = cppc_cpufreq_khz_to_perf(cpu_data, target_freq);
/* Return if it is exactly the same perf */
if (desired_perf == cpu_data->perf_ctrls.desired_perf)
return ret;
cpu_data->perf_ctrls.desired_perf = desired_perf;
freqs.old = policy->cur;
freqs.new = target_freq;
cpufreq_freq_transition_begin(policy, &freqs);
ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
cpufreq_freq_transition_end(policy, &freqs, ret != 0);
if (ret)
pr_debug("Failed to set target on CPU:%d. ret:%d\n",
cpu, ret);
return ret;
}
static int cppc_verify_policy(struct cpufreq_policy_data *policy)
{
cpufreq_verify_within_cpu_limits(policy);
return 0;
}
/*
* The PCC subspace describes the rate at which platform can accept commands
* on the shared PCC channel (including READs which do not count towards freq
* transition requests), so ideally we need to use the PCC values as a fallback
* if we don't have a platform specific transition_delay_us
*/
#ifdef CONFIG_ARM64
#include <asm/cputype.h>
static unsigned int cppc_cpufreq_get_transition_delay_us(unsigned int cpu)
{
unsigned long implementor = read_cpuid_implementor();
unsigned long part_num = read_cpuid_part_number();
switch (implementor) {
case ARM_CPU_IMP_QCOM:
switch (part_num) {
case QCOM_CPU_PART_FALKOR_V1:
case QCOM_CPU_PART_FALKOR:
return 10000;
}
}
return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
}
#else
static unsigned int cppc_cpufreq_get_transition_delay_us(unsigned int cpu)
{
return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
}
#endif
static struct cppc_cpudata *cppc_cpufreq_get_cpu_data(unsigned int cpu)
{
struct cppc_cpudata *cpu_data;
int ret;
cpu_data = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
if (!cpu_data)
goto out;
if (!zalloc_cpumask_var(&cpu_data->shared_cpu_map, GFP_KERNEL))
goto free_cpu;
ret = acpi_get_psd_map(cpu, cpu_data);
if (ret) {
pr_debug("Err parsing CPU%d PSD data: ret:%d\n", cpu, ret);
goto free_mask;
}
ret = cppc_get_perf_caps(cpu, &cpu_data->perf_caps);
if (ret) {
pr_debug("Err reading CPU%d perf caps: ret:%d\n", cpu, ret);
goto free_mask;
}
/* Convert the lowest and nominal freq from MHz to KHz */
cpu_data->perf_caps.lowest_freq *= 1000;
cpu_data->perf_caps.nominal_freq *= 1000;
list_add(&cpu_data->node, &cpu_data_list);
return cpu_data;
free_mask:
free_cpumask_var(cpu_data->shared_cpu_map);
free_cpu:
kfree(cpu_data);
out:
return NULL;
}
static void cppc_cpufreq_put_cpu_data(struct cpufreq_policy *policy)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
list_del(&cpu_data->node);
free_cpumask_var(cpu_data->shared_cpu_map);
kfree(cpu_data);
policy->driver_data = NULL;
}
static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
unsigned int cpu = policy->cpu;
struct cppc_cpudata *cpu_data;
struct cppc_perf_caps *caps;
int ret;
cpu_data = cppc_cpufreq_get_cpu_data(cpu);
if (!cpu_data) {
pr_err("Error in acquiring _CPC/_PSD data for CPU%d.\n", cpu);
return -ENODEV;
}
caps = &cpu_data->perf_caps;
policy->driver_data = cpu_data;
/*
* Set min to lowest nonlinear perf to avoid any efficiency penalty (see
* Section 8.4.7.1.1.5 of ACPI 6.1 spec)
*/
policy->min = cppc_cpufreq_perf_to_khz(cpu_data,
caps->lowest_nonlinear_perf);
policy->max = cppc_cpufreq_perf_to_khz(cpu_data,
caps->nominal_perf);
/*
* Set cpuinfo.min_freq to Lowest to make the full range of performance
* available if userspace wants to use any perf between lowest & lowest
* nonlinear perf
*/
policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu_data,
caps->lowest_perf);
policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu_data,
caps->nominal_perf);
policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu);
policy->shared_type = cpu_data->shared_type;
switch (policy->shared_type) {
case CPUFREQ_SHARED_TYPE_HW:
case CPUFREQ_SHARED_TYPE_NONE:
/* Nothing to be done - we'll have a policy for each CPU */
break;
case CPUFREQ_SHARED_TYPE_ANY:
/*
* All CPUs in the domain will share a policy and all cpufreq
* operations will use a single cppc_cpudata structure stored
* in policy->driver_data.
*/
cpumask_copy(policy->cpus, cpu_data->shared_cpu_map);
break;
default:
pr_debug("Unsupported CPU co-ord type: %d\n",
policy->shared_type);
ret = -EFAULT;
goto out;
}
/*
* If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost
* is supported.
*/
if (caps->highest_perf > caps->nominal_perf)
boost_supported = true;
/* Set policy->cur to max now. The governors will adjust later. */
policy->cur = cppc_cpufreq_perf_to_khz(cpu_data, caps->highest_perf);
cpu_data->perf_ctrls.desired_perf = caps->highest_perf;
ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
if (ret) {
pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
caps->highest_perf, cpu, ret);
goto out;
}
cppc_cpufreq_cpu_fie_init(policy);
return 0;
out:
cppc_cpufreq_put_cpu_data(policy);
return ret;
}
static int cppc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
struct cppc_perf_caps *caps = &cpu_data->perf_caps;
unsigned int cpu = policy->cpu;
int ret;
cppc_cpufreq_cpu_fie_exit(policy);
cpu_data->perf_ctrls.desired_perf = caps->lowest_perf;
ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
if (ret)
pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
caps->lowest_perf, cpu, ret);
cppc_cpufreq_put_cpu_data(policy);
return 0;
}
static inline u64 get_delta(u64 t1, u64 t0)
{
if (t1 > t0 || t0 > ~(u32)0)
return t1 - t0;
return (u32)t1 - (u32)t0;
}
static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data,
struct cppc_perf_fb_ctrs *fb_ctrs_t0,
struct cppc_perf_fb_ctrs *fb_ctrs_t1)
{
u64 delta_reference, delta_delivered;
u64 reference_perf;
reference_perf = fb_ctrs_t0->reference_perf;
delta_reference = get_delta(fb_ctrs_t1->reference,
fb_ctrs_t0->reference);
delta_delivered = get_delta(fb_ctrs_t1->delivered,
fb_ctrs_t0->delivered);
/* Check to avoid divide-by zero and invalid delivered_perf */
if (!delta_reference || !delta_delivered)
return cpu_data->perf_ctrls.desired_perf;
return (reference_perf * delta_delivered) / delta_reference;
}
static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
{
struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
struct cppc_cpudata *cpu_data = policy->driver_data;
u64 delivered_perf;
int ret;
cpufreq_cpu_put(policy);
ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t0);
if (ret)
return ret;
udelay(2); /* 2usec delay between sampling */
ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t1);
if (ret)
return ret;
delivered_perf = cppc_perf_from_fbctrs(cpu_data, &fb_ctrs_t0,
&fb_ctrs_t1);
return cppc_cpufreq_perf_to_khz(cpu_data, delivered_perf);
}
static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
struct cppc_perf_caps *caps = &cpu_data->perf_caps;
int ret;
if (!boost_supported) {
pr_err("BOOST not supported by CPU or firmware\n");
return -EINVAL;
}
if (state)
policy->max = cppc_cpufreq_perf_to_khz(cpu_data,
caps->highest_perf);
else
policy->max = cppc_cpufreq_perf_to_khz(cpu_data,
caps->nominal_perf);
policy->cpuinfo.max_freq = policy->max;
ret = freq_qos_update_request(policy->max_freq_req, policy->max);
if (ret < 0)
return ret;
return 0;
}
static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
return cpufreq_show_cpus(cpu_data->shared_cpu_map, buf);
}
cpufreq_freq_attr_ro(freqdomain_cpus);
static struct freq_attr *cppc_cpufreq_attr[] = {
&freqdomain_cpus,
NULL,
};
static struct cpufreq_driver cppc_cpufreq_driver = {
.flags = CPUFREQ_CONST_LOOPS,
.verify = cppc_verify_policy,
.target = cppc_cpufreq_set_target,
.get = cppc_cpufreq_get_rate,
.init = cppc_cpufreq_cpu_init,
.exit = cppc_cpufreq_cpu_exit,
.set_boost = cppc_cpufreq_set_boost,
.attr = cppc_cpufreq_attr,
.name = "cppc_cpufreq",
};
/*
* HISI platform does not support delivered performance counter and
* reference performance counter. It can calculate the performance using the
* platform specific mechanism. We reuse the desired performance register to
* store the real performance calculated by the platform.
*/
static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
struct cppc_cpudata *cpu_data = policy->driver_data;
u64 desired_perf;
int ret;
cpufreq_cpu_put(policy);
ret = cppc_get_desired_perf(cpu, &desired_perf);
if (ret < 0)
return -EIO;
return cppc_cpufreq_perf_to_khz(cpu_data, desired_perf);
}
static void cppc_check_hisi_workaround(void)
{
struct acpi_table_header *tbl;
acpi_status status = AE_OK;
int i;
status = acpi_get_table(ACPI_SIG_PCCT, 0, &tbl);
if (ACPI_FAILURE(status) || !tbl)
return;
for (i = 0; i < ARRAY_SIZE(wa_info); i++) {
if (!memcmp(wa_info[i].oem_id, tbl->oem_id, ACPI_OEM_ID_SIZE) &&
!memcmp(wa_info[i].oem_table_id, tbl->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
wa_info[i].oem_revision == tbl->oem_revision) {
/* Overwrite the get() callback */
cppc_cpufreq_driver.get = hisi_cppc_cpufreq_get_rate;
break;
}
}
acpi_put_table(tbl);
}
static int __init cppc_cpufreq_init(void)
{
int ret;
if ((acpi_disabled) || !acpi_cpc_valid())
return -ENODEV;
cppc_check_hisi_workaround();
cppc_freq_invariance_init();
ret = cpufreq_register_driver(&cppc_cpufreq_driver);
if (ret)
cppc_freq_invariance_exit();
return ret;
}
static inline void free_cpu_data(void)
{
struct cppc_cpudata *iter, *tmp;
list_for_each_entry_safe(iter, tmp, &cpu_data_list, node) {
free_cpumask_var(iter->shared_cpu_map);
list_del(&iter->node);
kfree(iter);
}
}
static void __exit cppc_cpufreq_exit(void)
{
cpufreq_unregister_driver(&cppc_cpufreq_driver);
cppc_freq_invariance_exit();
free_cpu_data();
}
module_exit(cppc_cpufreq_exit);
MODULE_AUTHOR("Ashwin Chaugule");
MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
MODULE_LICENSE("GPL");
late_initcall(cppc_cpufreq_init);
static const struct acpi_device_id cppc_acpi_ids[] __used = {
{ACPI_PROCESSOR_DEVICE_HID, },
{}
};
MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);