1 /* 2 * CPPC (Collaborative Processor Performance Control) driver for 3 * interfacing with the CPUfreq layer and governors. See 4 * cppc_acpi.c for CPPC specific methods. 5 * 6 * (C) Copyright 2014, 2015 Linaro Ltd. 7 * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org> 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; version 2 12 * of the License. 13 */ 14 15 #define pr_fmt(fmt) "CPPC Cpufreq:" fmt 16 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/delay.h> 20 #include <linux/cpu.h> 21 #include <linux/cpufreq.h> 22 #include <linux/dmi.h> 23 #include <linux/time.h> 24 #include <linux/vmalloc.h> 25 26 #include <asm/unaligned.h> 27 28 #include <acpi/cppc_acpi.h> 29 30 /* Minimum struct length needed for the DMI processor entry we want */ 31 #define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48 32 33 /* Offest in the DMI processor structure for the max frequency */ 34 #define DMI_PROCESSOR_MAX_SPEED 0x14 35 36 /* 37 * These structs contain information parsed from per CPU 38 * ACPI _CPC structures. 39 * e.g. For each CPU the highest, lowest supported 40 * performance capabilities, desired performance level 41 * requested etc. 42 */ 43 static struct cppc_cpudata **all_cpu_data; 44 45 /* Capture the max KHz from DMI */ 46 static u64 cppc_dmi_max_khz; 47 48 /* Callback function used to retrieve the max frequency from DMI */ 49 static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private) 50 { 51 const u8 *dmi_data = (const u8 *)dm; 52 u16 *mhz = (u16 *)private; 53 54 if (dm->type == DMI_ENTRY_PROCESSOR && 55 dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) { 56 u16 val = (u16)get_unaligned((const u16 *) 57 (dmi_data + DMI_PROCESSOR_MAX_SPEED)); 58 *mhz = val > *mhz ? val : *mhz; 59 } 60 } 61 62 /* Look up the max frequency in DMI */ 63 static u64 cppc_get_dmi_max_khz(void) 64 { 65 u16 mhz = 0; 66 67 dmi_walk(cppc_find_dmi_mhz, &mhz); 68 69 /* 70 * Real stupid fallback value, just in case there is no 71 * actual value set. 72 */ 73 mhz = mhz ? mhz : 1; 74 75 return (1000 * mhz); 76 } 77 78 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, 79 unsigned int target_freq, 80 unsigned int relation) 81 { 82 struct cppc_cpudata *cpu; 83 struct cpufreq_freqs freqs; 84 u32 desired_perf; 85 int ret = 0; 86 87 cpu = all_cpu_data[policy->cpu]; 88 89 desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz; 90 /* Return if it is exactly the same perf */ 91 if (desired_perf == cpu->perf_ctrls.desired_perf) 92 return ret; 93 94 cpu->perf_ctrls.desired_perf = desired_perf; 95 freqs.old = policy->cur; 96 freqs.new = target_freq; 97 98 cpufreq_freq_transition_begin(policy, &freqs); 99 ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls); 100 cpufreq_freq_transition_end(policy, &freqs, ret != 0); 101 102 if (ret) 103 pr_debug("Failed to set target on CPU:%d. ret:%d\n", 104 cpu->cpu, ret); 105 106 return ret; 107 } 108 109 static int cppc_verify_policy(struct cpufreq_policy *policy) 110 { 111 cpufreq_verify_within_cpu_limits(policy); 112 return 0; 113 } 114 115 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy) 116 { 117 int cpu_num = policy->cpu; 118 struct cppc_cpudata *cpu = all_cpu_data[cpu_num]; 119 int ret; 120 121 cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf; 122 123 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); 124 if (ret) 125 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n", 126 cpu->perf_caps.lowest_perf, cpu_num, ret); 127 } 128 129 /* 130 * The PCC subspace describes the rate at which platform can accept commands 131 * on the shared PCC channel (including READs which do not count towards freq 132 * trasition requests), so ideally we need to use the PCC values as a fallback 133 * if we don't have a platform specific transition_delay_us 134 */ 135 #ifdef CONFIG_ARM64 136 #include <asm/cputype.h> 137 138 static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu) 139 { 140 unsigned long implementor = read_cpuid_implementor(); 141 unsigned long part_num = read_cpuid_part_number(); 142 unsigned int delay_us = 0; 143 144 switch (implementor) { 145 case ARM_CPU_IMP_QCOM: 146 switch (part_num) { 147 case QCOM_CPU_PART_FALKOR_V1: 148 case QCOM_CPU_PART_FALKOR: 149 delay_us = 10000; 150 break; 151 default: 152 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC; 153 break; 154 } 155 break; 156 default: 157 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC; 158 break; 159 } 160 161 return delay_us; 162 } 163 164 #else 165 166 static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu) 167 { 168 return cppc_get_transition_latency(cpu) / NSEC_PER_USEC; 169 } 170 #endif 171 172 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) 173 { 174 struct cppc_cpudata *cpu; 175 unsigned int cpu_num = policy->cpu; 176 int ret = 0; 177 178 cpu = all_cpu_data[policy->cpu]; 179 180 cpu->cpu = cpu_num; 181 ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps); 182 183 if (ret) { 184 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n", 185 cpu_num, ret); 186 return ret; 187 } 188 189 cppc_dmi_max_khz = cppc_get_dmi_max_khz(); 190 191 /* 192 * Set min to lowest nonlinear perf to avoid any efficiency penalty (see 193 * Section 8.4.7.1.1.5 of ACPI 6.1 spec) 194 */ 195 policy->min = cpu->perf_caps.lowest_nonlinear_perf * cppc_dmi_max_khz / 196 cpu->perf_caps.highest_perf; 197 policy->max = cppc_dmi_max_khz; 198 199 /* 200 * Set cpuinfo.min_freq to Lowest to make the full range of performance 201 * available if userspace wants to use any perf between lowest & lowest 202 * nonlinear perf 203 */ 204 policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz / 205 cpu->perf_caps.highest_perf; 206 policy->cpuinfo.max_freq = cppc_dmi_max_khz; 207 208 policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num); 209 policy->shared_type = cpu->shared_type; 210 211 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) { 212 int i; 213 214 cpumask_copy(policy->cpus, cpu->shared_cpu_map); 215 216 for_each_cpu(i, policy->cpus) { 217 if (unlikely(i == policy->cpu)) 218 continue; 219 220 memcpy(&all_cpu_data[i]->perf_caps, &cpu->perf_caps, 221 sizeof(cpu->perf_caps)); 222 } 223 } else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) { 224 /* Support only SW_ANY for now. */ 225 pr_debug("Unsupported CPU co-ord type\n"); 226 return -EFAULT; 227 } 228 229 cpu->cur_policy = policy; 230 231 /* Set policy->cur to max now. The governors will adjust later. */ 232 policy->cur = cppc_dmi_max_khz; 233 cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf; 234 235 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); 236 if (ret) 237 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n", 238 cpu->perf_caps.highest_perf, cpu_num, ret); 239 240 return ret; 241 } 242 243 static struct cpufreq_driver cppc_cpufreq_driver = { 244 .flags = CPUFREQ_CONST_LOOPS, 245 .verify = cppc_verify_policy, 246 .target = cppc_cpufreq_set_target, 247 .init = cppc_cpufreq_cpu_init, 248 .stop_cpu = cppc_cpufreq_stop_cpu, 249 .name = "cppc_cpufreq", 250 }; 251 252 static int __init cppc_cpufreq_init(void) 253 { 254 int i, ret = 0; 255 struct cppc_cpudata *cpu; 256 257 if (acpi_disabled) 258 return -ENODEV; 259 260 all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL); 261 if (!all_cpu_data) 262 return -ENOMEM; 263 264 for_each_possible_cpu(i) { 265 all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL); 266 if (!all_cpu_data[i]) 267 goto out; 268 269 cpu = all_cpu_data[i]; 270 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL)) 271 goto out; 272 } 273 274 ret = acpi_get_psd_map(all_cpu_data); 275 if (ret) { 276 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n"); 277 goto out; 278 } 279 280 ret = cpufreq_register_driver(&cppc_cpufreq_driver); 281 if (ret) 282 goto out; 283 284 return ret; 285 286 out: 287 for_each_possible_cpu(i) { 288 cpu = all_cpu_data[i]; 289 if (!cpu) 290 break; 291 free_cpumask_var(cpu->shared_cpu_map); 292 kfree(cpu); 293 } 294 295 kfree(all_cpu_data); 296 return -ENODEV; 297 } 298 299 static void __exit cppc_cpufreq_exit(void) 300 { 301 struct cppc_cpudata *cpu; 302 int i; 303 304 cpufreq_unregister_driver(&cppc_cpufreq_driver); 305 306 for_each_possible_cpu(i) { 307 cpu = all_cpu_data[i]; 308 free_cpumask_var(cpu->shared_cpu_map); 309 kfree(cpu); 310 } 311 312 kfree(all_cpu_data); 313 } 314 315 module_exit(cppc_cpufreq_exit); 316 MODULE_AUTHOR("Ashwin Chaugule"); 317 MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec"); 318 MODULE_LICENSE("GPL"); 319 320 late_initcall(cppc_cpufreq_init); 321 322 static const struct acpi_device_id cppc_acpi_ids[] = { 323 {ACPI_PROCESSOR_DEVICE_HID, }, 324 {} 325 }; 326 327 MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids); 328