drivers/cpufreq/cppc_cpufreq.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * CPPC (Collaborative Processor Performance Control) driver for
   4  * interfacing with the CPUfreq layer and governors. See
   5  * cppc_acpi.c for CPPC specific methods.
   6  *
   7  * (C) Copyright 2014, 2015 Linaro Ltd.
   8  * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
   9  */
  10
  11 #define pr_fmt(fmt)     "CPPC Cpufreq:" fmt
  12
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/delay.h>
  16 #include <linux/cpu.h>
  17 #include <linux/cpufreq.h>
  18 #include <linux/dmi.h>
  19 #include <linux/time.h>
  20 #include <linux/vmalloc.h>
  21
  22 #include <asm/unaligned.h>
  23
  24 #include <acpi/cppc_acpi.h>
  25
  26 /* Minimum struct length needed for the DMI processor entry we want */
  27 #define DMI_ENTRY_PROCESSOR_MIN_LENGTH  48
  28
  29 /* Offest in the DMI processor structure for the max frequency */
  30 #define DMI_PROCESSOR_MAX_SPEED  0x14
  31
  32 /*
  33  * These structs contain information parsed from per CPU
  34  * ACPI _CPC structures.
  35  * e.g. For each CPU the highest, lowest supported
  36  * performance capabilities, desired performance level
  37  * requested etc.
  38  */
  39 static struct cppc_cpudata **all_cpu_data;
  40 static bool boost_supported;
  41
  42 struct cppc_workaround_oem_info {
  43         char oem_id[ACPI_OEM_ID_SIZE + 1];
  44         char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
  45         u32 oem_revision;
  46 };
  47
  48 static bool apply_hisi_workaround;
  49
  50 static struct cppc_workaround_oem_info wa_info[] = {
  51         {
  52                 .oem_id         = "HISI  ",
  53                 .oem_table_id   = "HIP07   ",
  54                 .oem_revision   = 0,
  55         }, {
  56                 .oem_id         = "HISI  ",
  57                 .oem_table_id   = "HIP08   ",
  58                 .oem_revision   = 0,
  59         }
  60 };
  61
  62 static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
  63                                         unsigned int perf);
  64
  65 /*
  66  * HISI platform does not support delivered performance counter and
  67  * reference performance counter. It can calculate the performance using the
  68  * platform specific mechanism. We reuse the desired performance register to
  69  * store the real performance calculated by the platform.
  70  */
  71 static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpunum)
  72 {
  73         struct cppc_cpudata *cpudata = all_cpu_data[cpunum];
  74         u64 desired_perf;
  75         int ret;
  76
  77         ret = cppc_get_desired_perf(cpunum, &desired_perf);
  78         if (ret < 0)
  79                 return -EIO;
  80
  81         return cppc_cpufreq_perf_to_khz(cpudata, desired_perf);
  82 }
  83
  84 static void cppc_check_hisi_workaround(void)
  85 {
  86         struct acpi_table_header *tbl;
  87         acpi_status status = AE_OK;
  88         int i;
  89
  90         status = acpi_get_table(ACPI_SIG_PCCT, 0, &tbl);
  91         if (ACPI_FAILURE(status) || !tbl)
  92                 return;
  93
  94         for (i = 0; i < ARRAY_SIZE(wa_info); i++) {
  95                 if (!memcmp(wa_info[i].oem_id, tbl->oem_id, ACPI_OEM_ID_SIZE) &&
  96                     !memcmp(wa_info[i].oem_table_id, tbl->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
  97                     wa_info[i].oem_revision == tbl->oem_revision) {
  98                         apply_hisi_workaround = true;
  99                         break;
 100                 }
 101         }
 102
 103         acpi_put_table(tbl);
 104 }
 105
 106 /* Callback function used to retrieve the max frequency from DMI */
 107 static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
 108 {
 109         const u8 *dmi_data = (const u8 *)dm;
 110         u16 *mhz = (u16 *)private;
 111
 112         if (dm->type == DMI_ENTRY_PROCESSOR &&
 113             dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
 114                 u16 val = (u16)get_unaligned((const u16 *)
 115                                 (dmi_data + DMI_PROCESSOR_MAX_SPEED));
 116                 *mhz = val > *mhz ? val : *mhz;
 117         }
 118 }
 119
 120 /* Look up the max frequency in DMI */
 121 static u64 cppc_get_dmi_max_khz(void)
 122 {
 123         u16 mhz = 0;
 124
 125         dmi_walk(cppc_find_dmi_mhz, &mhz);
 126
 127         /*
 128          * Real stupid fallback value, just in case there is no
 129          * actual value set.
 130          */
 131         mhz = mhz ? mhz : 1;
 132
 133         return (1000 * mhz);
 134 }
 135
 136 /*
 137  * If CPPC lowest_freq and nominal_freq registers are exposed then we can
 138  * use them to convert perf to freq and vice versa
 139  *
 140  * If the perf/freq point lies between Nominal and Lowest, we can treat
 141  * (Low perf, Low freq) and (Nom Perf, Nom freq) as 2D co-ordinates of a line
 142  * and extrapolate the rest
 143  * For perf/freq > Nominal, we use the ratio perf:freq at Nominal for conversion
 144  */
 145 static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
 146                                         unsigned int perf)
 147 {
 148         static u64 max_khz;
 149         struct cppc_perf_caps *caps = &cpu->perf_caps;
 150         u64 mul, div;
 151
 152         if (caps->lowest_freq && caps->nominal_freq) {
 153                 if (perf >= caps->nominal_perf) {
 154                         mul = caps->nominal_freq;
 155                         div = caps->nominal_perf;
 156                 } else {
 157                         mul = caps->nominal_freq - caps->lowest_freq;
 158                         div = caps->nominal_perf - caps->lowest_perf;
 159                 }
 160         } else {
 161                 if (!max_khz)
 162                         max_khz = cppc_get_dmi_max_khz();
 163                 mul = max_khz;
 164                 div = cpu->perf_caps.highest_perf;
 165         }
 166         return (u64)perf * mul / div;
 167 }
 168
 169 static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu,
 170                                         unsigned int freq)
 171 {
 172         static u64 max_khz;
 173         struct cppc_perf_caps *caps = &cpu->perf_caps;
 174         u64  mul, div;
 175
 176         if (caps->lowest_freq && caps->nominal_freq) {
 177                 if (freq >= caps->nominal_freq) {
 178                         mul = caps->nominal_perf;
 179                         div = caps->nominal_freq;
 180                 } else {
 181                         mul = caps->lowest_perf;
 182                         div = caps->lowest_freq;
 183                 }
 184         } else {
 185                 if (!max_khz)
 186                         max_khz = cppc_get_dmi_max_khz();
 187                 mul = cpu->perf_caps.highest_perf;
 188                 div = max_khz;
 189         }
 190
 191         return (u64)freq * mul / div;
 192 }
 193
 194 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
 195                 unsigned int target_freq,
 196                 unsigned int relation)
 197 {
 198         struct cppc_cpudata *cpu;
 199         struct cpufreq_freqs freqs;
 200         u32 desired_perf;
 201         int ret = 0;
 202
 203         cpu = all_cpu_data[policy->cpu];
 204
 205         desired_perf = cppc_cpufreq_khz_to_perf(cpu, target_freq);
 206         /* Return if it is exactly the same perf */
 207         if (desired_perf == cpu->perf_ctrls.desired_perf)
 208                 return ret;
 209
 210         cpu->perf_ctrls.desired_perf = desired_perf;
 211         freqs.old = policy->cur;
 212         freqs.new = target_freq;
 213
 214         cpufreq_freq_transition_begin(policy, &freqs);
 215         ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
 216         cpufreq_freq_transition_end(policy, &freqs, ret != 0);
 217
 218         if (ret)
 219                 pr_debug("Failed to set target on CPU:%d. ret:%d\n",
 220                                 cpu->cpu, ret);
 221
 222         return ret;
 223 }
 224
 225 static int cppc_verify_policy(struct cpufreq_policy_data *policy)
 226 {
 227         cpufreq_verify_within_cpu_limits(policy);
 228         return 0;
 229 }
 230
 231 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
 232 {
 233         int cpu_num = policy->cpu;
 234         struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
 235         int ret;
 236
 237         cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
 238
 239         ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
 240         if (ret)
 241                 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
 242                                 cpu->perf_caps.lowest_perf, cpu_num, ret);
 243 }
 244
 245 /*
 246  * The PCC subspace describes the rate at which platform can accept commands
 247  * on the shared PCC channel (including READs which do not count towards freq
 248  * trasition requests), so ideally we need to use the PCC values as a fallback
 249  * if we don't have a platform specific transition_delay_us
 250  */
 251 #ifdef CONFIG_ARM64
 252 #include <asm/cputype.h>
 253
 254 static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
 255 {
 256         unsigned long implementor = read_cpuid_implementor();
 257         unsigned long part_num = read_cpuid_part_number();
 258         unsigned int delay_us = 0;
 259
 260         switch (implementor) {
 261         case ARM_CPU_IMP_QCOM:
 262                 switch (part_num) {
 263                 case QCOM_CPU_PART_FALKOR_V1:
 264                 case QCOM_CPU_PART_FALKOR:
 265                         delay_us = 10000;
 266                         break;
 267                 default:
 268                         delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
 269                         break;
 270                 }
 271                 break;
 272         default:
 273                 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
 274                 break;
 275         }
 276
 277         return delay_us;
 278 }
 279
 280 #else
 281
 282 static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
 283 {
 284         return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
 285 }
 286 #endif
 287
 288 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 289 {
 290         struct cppc_cpudata *cpu;
 291         unsigned int cpu_num = policy->cpu;
 292         int ret = 0;
 293
 294         cpu = all_cpu_data[policy->cpu];
 295
 296         cpu->cpu = cpu_num;
 297         ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
 298
 299         if (ret) {
 300                 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
 301                                 cpu_num, ret);
 302                 return ret;
 303         }
 304
 305         /* Convert the lowest and nominal freq from MHz to KHz */
 306         cpu->perf_caps.lowest_freq *= 1000;
 307         cpu->perf_caps.nominal_freq *= 1000;
 308
 309         /*
 310          * Set min to lowest nonlinear perf to avoid any efficiency penalty (see
 311          * Section 8.4.7.1.1.5 of ACPI 6.1 spec)
 312          */
 313         policy->min = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_nonlinear_perf);
 314         policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
 315
 316         /*
 317          * Set cpuinfo.min_freq to Lowest to make the full range of performance
 318          * available if userspace wants to use any perf between lowest & lowest
 319          * nonlinear perf
 320          */
 321         policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_perf);
 322         policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
 323
 324         policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num);
 325         policy->shared_type = cpu->shared_type;
 326
 327         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
 328                 int i;
 329
 330                 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
 331
 332                 for_each_cpu(i, policy->cpus) {
 333                         if (unlikely(i == policy->cpu))
 334                                 continue;
 335
 336                         memcpy(&all_cpu_data[i]->perf_caps, &cpu->perf_caps,
 337                                sizeof(cpu->perf_caps));
 338                 }
 339         } else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
 340                 /* Support only SW_ANY for now. */
 341                 pr_debug("Unsupported CPU co-ord type\n");
 342                 return -EFAULT;
 343         }
 344
 345         cpu->cur_policy = policy;
 346
 347         /*
 348          * If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost
 349          * is supported.
 350          */
 351         if (cpu->perf_caps.highest_perf > cpu->perf_caps.nominal_perf)
 352                 boost_supported = true;
 353
 354         /* Set policy->cur to max now. The governors will adjust later. */
 355         policy->cur = cppc_cpufreq_perf_to_khz(cpu,
 356                                         cpu->perf_caps.highest_perf);
 357         cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
 358
 359         ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
 360         if (ret)
 361                 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
 362                                 cpu->perf_caps.highest_perf, cpu_num, ret);
 363
 364         return ret;
 365 }
 366
 367 static inline u64 get_delta(u64 t1, u64 t0)
 368 {
 369         if (t1 > t0 || t0 > ~(u32)0)
 370                 return t1 - t0;
 371
 372         return (u32)t1 - (u32)t0;
 373 }
 374
 375 static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu,
 376                                      struct cppc_perf_fb_ctrs fb_ctrs_t0,
 377                                      struct cppc_perf_fb_ctrs fb_ctrs_t1)
 378 {
 379         u64 delta_reference, delta_delivered;
 380         u64 reference_perf, delivered_perf;
 381
 382         reference_perf = fb_ctrs_t0.reference_perf;
 383
 384         delta_reference = get_delta(fb_ctrs_t1.reference,
 385                                     fb_ctrs_t0.reference);
 386         delta_delivered = get_delta(fb_ctrs_t1.delivered,
 387                                     fb_ctrs_t0.delivered);
 388
 389         /* Check to avoid divide-by zero */
 390         if (delta_reference || delta_delivered)
 391                 delivered_perf = (reference_perf * delta_delivered) /
 392                                         delta_reference;
 393         else
 394                 delivered_perf = cpu->perf_ctrls.desired_perf;
 395
 396         return cppc_cpufreq_perf_to_khz(cpu, delivered_perf);
 397 }
 398
 399 static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
 400 {
 401         struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
 402         struct cppc_cpudata *cpu = all_cpu_data[cpunum];
 403         int ret;
 404
 405         if (apply_hisi_workaround)
 406                 return hisi_cppc_cpufreq_get_rate(cpunum);
 407
 408         ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t0);
 409         if (ret)
 410                 return ret;
 411
 412         udelay(2); /* 2usec delay between sampling */
 413
 414         ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t1);
 415         if (ret)
 416                 return ret;
 417
 418         return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1);
 419 }
 420
 421 static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
 422 {
 423         struct cppc_cpudata *cpudata;
 424         int ret;
 425
 426         if (!boost_supported) {
 427                 pr_err("BOOST not supported by CPU or firmware\n");
 428                 return -EINVAL;
 429         }
 430
 431         cpudata = all_cpu_data[policy->cpu];
 432         if (state)
 433                 policy->max = cppc_cpufreq_perf_to_khz(cpudata,
 434                                         cpudata->perf_caps.highest_perf);
 435         else
 436                 policy->max = cppc_cpufreq_perf_to_khz(cpudata,
 437                                         cpudata->perf_caps.nominal_perf);
 438         policy->cpuinfo.max_freq = policy->max;
 439
 440         ret = freq_qos_update_request(policy->max_freq_req, policy->max);
 441         if (ret < 0)
 442                 return ret;
 443
 444         return 0;
 445 }
 446
 447 static struct cpufreq_driver cppc_cpufreq_driver = {
 448         .flags = CPUFREQ_CONST_LOOPS,
 449         .verify = cppc_verify_policy,
 450         .target = cppc_cpufreq_set_target,
 451         .get = cppc_cpufreq_get_rate,
 452         .init = cppc_cpufreq_cpu_init,
 453         .stop_cpu = cppc_cpufreq_stop_cpu,
 454         .set_boost = cppc_cpufreq_set_boost,
 455         .name = "cppc_cpufreq",
 456 };
 457
 458 static int __init cppc_cpufreq_init(void)
 459 {
 460         int i, ret = 0;
 461         struct cppc_cpudata *cpu;
 462
 463         if (acpi_disabled)
 464                 return -ENODEV;
 465
 466         all_cpu_data = kcalloc(num_possible_cpus(), sizeof(void *),
 467                                GFP_KERNEL);
 468         if (!all_cpu_data)
 469                 return -ENOMEM;
 470
 471         for_each_possible_cpu(i) {
 472                 all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
 473                 if (!all_cpu_data[i])
 474                         goto out;
 475
 476                 cpu = all_cpu_data[i];
 477                 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
 478                         goto out;
 479         }
 480
 481         ret = acpi_get_psd_map(all_cpu_data);
 482         if (ret) {
 483                 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
 484                 goto out;
 485         }
 486
 487         cppc_check_hisi_workaround();
 488
 489         ret = cpufreq_register_driver(&cppc_cpufreq_driver);
 490         if (ret)
 491                 goto out;
 492
 493         return ret;
 494
 495 out:
 496         for_each_possible_cpu(i) {
 497                 cpu = all_cpu_data[i];
 498                 if (!cpu)
 499                         break;
 500                 free_cpumask_var(cpu->shared_cpu_map);
 501                 kfree(cpu);
 502         }
 503
 504         kfree(all_cpu_data);
 505         return -ENODEV;
 506 }
 507
 508 static void __exit cppc_cpufreq_exit(void)
 509 {
 510         struct cppc_cpudata *cpu;
 511         int i;
 512
 513         cpufreq_unregister_driver(&cppc_cpufreq_driver);
 514
 515         for_each_possible_cpu(i) {
 516                 cpu = all_cpu_data[i];
 517                 free_cpumask_var(cpu->shared_cpu_map);
 518                 kfree(cpu);
 519         }
 520
 521         kfree(all_cpu_data);
 522 }
 523
 524 module_exit(cppc_cpufreq_exit);
 525 MODULE_AUTHOR("Ashwin Chaugule");
 526 MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
 527 MODULE_LICENSE("GPL");
 528
 529 late_initcall(cppc_cpufreq_init);
 530
 531 static const struct acpi_device_id cppc_acpi_ids[] __used = {
 532         {ACPI_PROCESSOR_DEVICE_HID, },
 533         {}
 534 };
 535
 536 MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);