/* * 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 * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; version 2 * of the License. */ #define pr_fmt(fmt) "CPPC Cpufreq:" fmt #include #include #include #include #include #include #include #include #include #include /* 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; /* 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 = cpu->perf_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 = cpu->perf_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 *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 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.highest_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.highest_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; /* 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 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, .name = "cppc_cpufreq", }; 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; } 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[] = { {ACPI_PROCESSOR_DEVICE_HID, }, {} }; MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);