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/kernel.h>
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/dmi.h>
 #include <linux/time.h>
 #include <linux/vmalloc.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

 /* Offest in the DMI processor structure for the max frequency */
 #define DMI_PROCESSOR_MAX_SPEED  0x14

 /*
  * These structs contain information parsed from per CPU
  * ACPI _CPC structures.
  * e.g. For each CPU the highest, lowest supported
  * performance capabilities, desired performance level
  * requested etc.
  */
 static struct cppc_cpudata **all_cpu_data;
 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,
 	}
 };

 /* 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
  *
  * If the perf/freq point lies between Nominal and Lowest, we can treat
  * (Low perf, Low freq) and (Nom Perf, Nom freq) as 2D co-ordinates of a line
  * and extrapolate the rest
  * For perf/freq > Nominal, we use the ratio perf:freq at Nominal for conversion
  */
 static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
 					unsigned int perf)
 {
 	static u64 max_khz;
 	struct cppc_perf_caps *caps = &cpu->perf_caps;
 	u64 mul, div;

 	if (caps->lowest_freq && caps->nominal_freq) {
 		if (perf >= caps->nominal_perf) {
 			mul = caps->nominal_freq;
 			div = caps->nominal_perf;
 		} else {
 			mul = caps->nominal_freq - caps->lowest_freq;
 			div = caps->nominal_perf - caps->lowest_perf;
 		}
 	} else {
 		if (!max_khz)
 			max_khz = cppc_get_dmi_max_khz();
 		mul = max_khz;
 		div = caps->highest_perf;
 	}
 	return (u64)perf * mul / div;
 }

 static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu,
 					unsigned int freq)
 {
 	static u64 max_khz;
 	struct cppc_perf_caps *caps = &cpu->perf_caps;
 	u64  mul, div;

 	if (caps->lowest_freq && caps->nominal_freq) {
 		if (freq >= caps->nominal_freq) {
 			mul = caps->nominal_perf;
 			div = caps->nominal_freq;
 		} else {
 			mul = caps->lowest_perf;
 			div = caps->lowest_freq;
 		}
 	} else {
 		if (!max_khz)
 			max_khz = cppc_get_dmi_max_khz();
 		mul = caps->highest_perf;
 		div = max_khz;
 	}

 	return (u64)freq * mul / div;
 }

 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
 		unsigned int target_freq,
 		unsigned int relation)
 {
 	struct cppc_cpudata *cpu;
 	struct cpufreq_freqs freqs;
 	u32 desired_perf;
 	int ret = 0;

 	cpu = all_cpu_data[policy->cpu];

 	desired_perf = cppc_cpufreq_khz_to_perf(cpu, target_freq);
 	/* Return if it is exactly the same perf */
 	if (desired_perf == cpu->perf_ctrls.desired_perf)
 		return ret;

 	cpu->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, &cpu->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->cpu, ret);

 	return ret;
 }

 static int cppc_verify_policy(struct cpufreq_policy_data *policy)
 {
 	cpufreq_verify_within_cpu_limits(policy);
 	return 0;
 }

 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
 {
 	int cpu_num = policy->cpu;
 	struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
 	int ret;

 	cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;

 	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
 	if (ret)
 		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
 				cpu->perf_caps.lowest_perf, cpu_num, ret);
 }

 /*
  * 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
  * trasition 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(int cpu)
 {
 	unsigned long implementor = read_cpuid_implementor();
 	unsigned long part_num = read_cpuid_part_number();
 	unsigned int delay_us = 0;

 	switch (implementor) {
 	case ARM_CPU_IMP_QCOM:
 		switch (part_num) {
 		case QCOM_CPU_PART_FALKOR_V1:
 		case QCOM_CPU_PART_FALKOR:
 			delay_us = 10000;
 			break;
 		default:
 			delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
 			break;
 		}
 		break;
 	default:
 		delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
 		break;
 	}

 	return delay_us;
 }

 #else

 static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
 {
 	return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
 }
 #endif

 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 {
 	struct cppc_cpudata *cpu;
 	unsigned int cpu_num = policy->cpu;
 	int ret = 0;

 	cpu = all_cpu_data[policy->cpu];

 	cpu->cpu = cpu_num;
 	ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);

 	if (ret) {
 		pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
 				cpu_num, ret);
 		return ret;
 	}

 	/* Convert the lowest and nominal freq from MHz to KHz */
 	cpu->perf_caps.lowest_freq *= 1000;
 	cpu->perf_caps.nominal_freq *= 1000;

 	/*
 	 * 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, cpu->perf_caps.lowest_nonlinear_perf);
 	policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_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, cpu->perf_caps.lowest_perf);
 	policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);

 	policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num);
 	policy->shared_type = cpu->shared_type;

 	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
 		int i;

 		cpumask_copy(policy->cpus, cpu->shared_cpu_map);

 		for_each_cpu(i, policy->cpus) {
 			if (unlikely(i == policy->cpu))
 				continue;

 			memcpy(&all_cpu_data[i]->perf_caps, &cpu->perf_caps,
 			       sizeof(cpu->perf_caps));
 		}
 	} else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
 		/* Support only SW_ANY for now. */
 		pr_debug("Unsupported CPU co-ord type\n");
 		return -EFAULT;
 	}

 	cpu->cur_policy = policy;

 	/*
 	 * If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost
 	 * is supported.
 	 */
 	if (cpu->perf_caps.highest_perf > cpu->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,
 					cpu->perf_caps.highest_perf);
 	cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;

 	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
 	if (ret)
 		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
 				cpu->perf_caps.highest_perf, cpu_num, ret);

 	return ret;
 }

 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_get_rate_from_fbctrs(struct cppc_cpudata *cpu,
 				     struct cppc_perf_fb_ctrs fb_ctrs_t0,
 				     struct cppc_perf_fb_ctrs fb_ctrs_t1)
 {
 	u64 delta_reference, delta_delivered;
 	u64 reference_perf, delivered_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 */
 	if (delta_reference || delta_delivered)
 		delivered_perf = (reference_perf * delta_delivered) /
 					delta_reference;
 	else
 		delivered_perf = cpu->perf_ctrls.desired_perf;

 	return cppc_cpufreq_perf_to_khz(cpu, delivered_perf);
 }

 static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
 {
 	struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
 	struct cppc_cpudata *cpu = all_cpu_data[cpunum];
 	int ret;

 	ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t0);
 	if (ret)
 		return ret;

 	udelay(2); /* 2usec delay between sampling */

 	ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t1);
 	if (ret)
 		return ret;

 	return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1);
 }

 static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
 {
 	struct cppc_cpudata *cpudata;
 	int ret;

 	if (!boost_supported) {
 		pr_err("BOOST not supported by CPU or firmware\n");
 		return -EINVAL;
 	}

 	cpudata = all_cpu_data[policy->cpu];
 	if (state)
 		policy->max = cppc_cpufreq_perf_to_khz(cpudata,
 					cpudata->perf_caps.highest_perf);
 	else
 		policy->max = cppc_cpufreq_perf_to_khz(cpudata,
 					cpudata->perf_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 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,
 	.stop_cpu = cppc_cpufreq_stop_cpu,
 	.set_boost = cppc_cpufreq_set_boost,
 	.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 cpunum)
 {
 	struct cppc_cpudata *cpudata = all_cpu_data[cpunum];
 	u64 desired_perf;
 	int ret;

 	ret = cppc_get_desired_perf(cpunum, &desired_perf);
 	if (ret < 0)
 		return -EIO;

 	return cppc_cpufreq_perf_to_khz(cpudata, 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 i, ret = 0;
 	struct cppc_cpudata *cpu;

 	if (acpi_disabled)
 		return -ENODEV;

 	all_cpu_data = kcalloc(num_possible_cpus(), sizeof(void *),
 			       GFP_KERNEL);
 	if (!all_cpu_data)
 		return -ENOMEM;

 	for_each_possible_cpu(i) {
 		all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
 		if (!all_cpu_data[i])
 			goto out;

 		cpu = all_cpu_data[i];
 		if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
 			goto out;
 	}

 	ret = acpi_get_psd_map(all_cpu_data);
 	if (ret) {
 		pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
 		goto out;
 	}

 	cppc_check_hisi_workaround();

 	ret = cpufreq_register_driver(&cppc_cpufreq_driver);
 	if (ret)
 		goto out;

 	return ret;

 out:
 	for_each_possible_cpu(i) {
 		cpu = all_cpu_data[i];
 		if (!cpu)
 			break;
 		free_cpumask_var(cpu->shared_cpu_map);
 		kfree(cpu);
 	}

 	kfree(all_cpu_data);
 	return -ENODEV;
 }

 static void __exit cppc_cpufreq_exit(void)
 {
 	struct cppc_cpudata *cpu;
 	int i;

 	cpufreq_unregister_driver(&cppc_cpufreq_driver);

 	for_each_possible_cpu(i) {
 		cpu = all_cpu_data[i];
 		free_cpumask_var(cpu->shared_cpu_map);
 		kfree(cpu);
 	}

 	kfree(all_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/kernel.h>
	#include <linux/module.h>
	#include <linux/delay.h>
	#include <linux/cpu.h>
	#include <linux/cpufreq.h>
	#include <linux/dmi.h>
	#include <linux/time.h>
	#include <linux/vmalloc.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

	/* Offest in the DMI processor structure for the max frequency */
	#define DMI_PROCESSOR_MAX_SPEED 0x14

	/*
	* These structs contain information parsed from per CPU
	* ACPI _CPC structures.
	* e.g. For each CPU the highest, lowest supported
	* performance capabilities, desired performance level
	* requested etc.
	*/
	static struct cppc_cpudata **all_cpu_data;
	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,
	}
	};

	/* 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
	*
	* If the perf/freq point lies between Nominal and Lowest, we can treat
	* (Low perf, Low freq) and (Nom Perf, Nom freq) as 2D co-ordinates of a line
	* and extrapolate the rest
	* For perf/freq > Nominal, we use the ratio perf:freq at Nominal for conversion
	*/
	static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
	unsigned int perf)
	{
	static u64 max_khz;
	struct cppc_perf_caps *caps = &cpu->perf_caps;
	u64 mul, div;

	if (caps->lowest_freq && caps->nominal_freq) {
	if (perf >= caps->nominal_perf) {
	mul = caps->nominal_freq;
	div = caps->nominal_perf;
	} else {
	mul = caps->nominal_freq - caps->lowest_freq;
	div = caps->nominal_perf - caps->lowest_perf;
	}
	} else {
	if (!max_khz)
	max_khz = cppc_get_dmi_max_khz();
	mul = max_khz;
	div = caps->highest_perf;
	}
	return (u64)perf * mul / div;
	}

	static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu,
	unsigned int freq)
	{
	static u64 max_khz;
	struct cppc_perf_caps *caps = &cpu->perf_caps;
	u64 mul, div;

	if (caps->lowest_freq && caps->nominal_freq) {
	if (freq >= caps->nominal_freq) {
	mul = caps->nominal_perf;
	div = caps->nominal_freq;
	} else {
	mul = caps->lowest_perf;
	div = caps->lowest_freq;
	}
	} else {
	if (!max_khz)
	max_khz = cppc_get_dmi_max_khz();
	mul = caps->highest_perf;
	div = max_khz;
	}

	return (u64)freq * mul / div;
	}

	static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
	unsigned int target_freq,
	unsigned int relation)
	{
	struct cppc_cpudata *cpu;
	struct cpufreq_freqs freqs;
	u32 desired_perf;
	int ret = 0;

	cpu = all_cpu_data[policy->cpu];

	desired_perf = cppc_cpufreq_khz_to_perf(cpu, target_freq);
	/* Return if it is exactly the same perf */
	if (desired_perf == cpu->perf_ctrls.desired_perf)
	return ret;

	cpu->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, &cpu->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->cpu, ret);

	return ret;
	}

	static int cppc_verify_policy(struct cpufreq_policy_data *policy)
	{
	cpufreq_verify_within_cpu_limits(policy);
	return 0;
	}

	static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
	{
	int cpu_num = policy->cpu;
	struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
	int ret;

	cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;

	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
	if (ret)
	pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
	cpu->perf_caps.lowest_perf, cpu_num, ret);
	}

	/*
	* 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
	* trasition 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(int cpu)
	{
	unsigned long implementor = read_cpuid_implementor();
	unsigned long part_num = read_cpuid_part_number();
	unsigned int delay_us = 0;

	switch (implementor) {
	case ARM_CPU_IMP_QCOM:
	switch (part_num) {
	case QCOM_CPU_PART_FALKOR_V1:
	case QCOM_CPU_PART_FALKOR:
	delay_us = 10000;
	break;
	default:
	delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
	break;
	}
	break;
	default:
	delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
	break;
	}

	return delay_us;
	}

	#else

	static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
	{
	return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
	}
	#endif

	static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
	{
	struct cppc_cpudata *cpu;
	unsigned int cpu_num = policy->cpu;
	int ret = 0;

	cpu = all_cpu_data[policy->cpu];

	cpu->cpu = cpu_num;
	ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);

	if (ret) {
	pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
	cpu_num, ret);
	return ret;
	}

	/* Convert the lowest and nominal freq from MHz to KHz */
	cpu->perf_caps.lowest_freq *= 1000;
	cpu->perf_caps.nominal_freq *= 1000;

	/*
	* 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, cpu->perf_caps.lowest_nonlinear_perf);
	policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_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, cpu->perf_caps.lowest_perf);
	policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);

	policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num);
	policy->shared_type = cpu->shared_type;

	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
	int i;

	cpumask_copy(policy->cpus, cpu->shared_cpu_map);

	for_each_cpu(i, policy->cpus) {
	if (unlikely(i == policy->cpu))
	continue;

	memcpy(&all_cpu_data[i]->perf_caps, &cpu->perf_caps,
	sizeof(cpu->perf_caps));
	}
	} else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
	/* Support only SW_ANY for now. */
	pr_debug("Unsupported CPU co-ord type\n");
	return -EFAULT;
	}

	cpu->cur_policy = policy;

	/*
	* If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost
	* is supported.
	*/
	if (cpu->perf_caps.highest_perf > cpu->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,
	cpu->perf_caps.highest_perf);
	cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;

	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
	if (ret)
	pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
	cpu->perf_caps.highest_perf, cpu_num, ret);

	return ret;
	}

	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_get_rate_from_fbctrs(struct cppc_cpudata *cpu,
	struct cppc_perf_fb_ctrs fb_ctrs_t0,
	struct cppc_perf_fb_ctrs fb_ctrs_t1)
	{
	u64 delta_reference, delta_delivered;
	u64 reference_perf, delivered_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 */
	if (delta_reference \|\| delta_delivered)
	delivered_perf = (reference_perf * delta_delivered) /
	delta_reference;
	else
	delivered_perf = cpu->perf_ctrls.desired_perf;

	return cppc_cpufreq_perf_to_khz(cpu, delivered_perf);
	}

	static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
	{
	struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
	struct cppc_cpudata *cpu = all_cpu_data[cpunum];
	int ret;

	ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t0);
	if (ret)
	return ret;

	udelay(2); /* 2usec delay between sampling */

	ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t1);
	if (ret)
	return ret;

	return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1);
	}

	static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
	{
	struct cppc_cpudata *cpudata;
	int ret;

	if (!boost_supported) {
	pr_err("BOOST not supported by CPU or firmware\n");
	return -EINVAL;
	}

	cpudata = all_cpu_data[policy->cpu];
	if (state)
	policy->max = cppc_cpufreq_perf_to_khz(cpudata,
	cpudata->perf_caps.highest_perf);
	else
	policy->max = cppc_cpufreq_perf_to_khz(cpudata,
	cpudata->perf_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 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,
	.stop_cpu = cppc_cpufreq_stop_cpu,
	.set_boost = cppc_cpufreq_set_boost,
	.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 cpunum)
	{
	struct cppc_cpudata *cpudata = all_cpu_data[cpunum];
	u64 desired_perf;
	int ret;

	ret = cppc_get_desired_perf(cpunum, &desired_perf);
	if (ret < 0)
	return -EIO;

	return cppc_cpufreq_perf_to_khz(cpudata, 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 i, ret = 0;
	struct cppc_cpudata *cpu;

	if (acpi_disabled)
	return -ENODEV;

	all_cpu_data = kcalloc(num_possible_cpus(), sizeof(void *),
	GFP_KERNEL);
	if (!all_cpu_data)
	return -ENOMEM;

	for_each_possible_cpu(i) {
	all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
	if (!all_cpu_data[i])
	goto out;

	cpu = all_cpu_data[i];
	if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
	goto out;
	}

	ret = acpi_get_psd_map(all_cpu_data);
	if (ret) {
	pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
	goto out;
	}

	cppc_check_hisi_workaround();

	ret = cpufreq_register_driver(&cppc_cpufreq_driver);
	if (ret)
	goto out;

	return ret;

	out:
	for_each_possible_cpu(i) {
	cpu = all_cpu_data[i];
	if (!cpu)
	break;
	free_cpumask_var(cpu->shared_cpu_map);
	kfree(cpu);
	}

	kfree(all_cpu_data);
	return -ENODEV;
	}

	static void __exit cppc_cpufreq_exit(void)
	{
	struct cppc_cpudata *cpu;
	int i;

	cpufreq_unregister_driver(&cppc_cpufreq_driver);

	for_each_possible_cpu(i) {
	cpu = all_cpu_data[i];
	free_cpumask_var(cpu->shared_cpu_map);
	kfree(cpu);
	}

	kfree(all_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);