drivers/cpufreq/cppc_cpufreq.c - linux - Git at Google

 // 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);
	// 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);