path: root/drivers/cpufreq/cppc_cpufreq.c

// 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,
	}
};

static struct cpufreq_driver cppc_cpufreq_driver;

static enum {
	FIE_UNSET = -1,
	FIE_ENABLED,
	FIE_DISABLED
} fie_disabled = FIE_UNSET;

#ifdef CONFIG_ACPI_CPPC_CPUFREQ_FIE
module_param(fie_disabled, int, 0444);
MODULE_PARM_DESC(fie_disabled, "Disable Frequency Invariance Engine (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 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 (fie_disabled)
		return;

	for_each_cpu(