root/drivers/cpufreq/cppc_cpufreq.c

DEFINITIONS

1. hisi_cppc_cpufreq_get_rate
2. cppc_check_hisi_workaround
3. cppc_find_dmi_mhz
4. cppc_get_dmi_max_khz
5. cppc_cpufreq_perf_to_khz
6. cppc_cpufreq_khz_to_perf
7. cppc_cpufreq_set_target
8. cppc_verify_policy
9. cppc_cpufreq_stop_cpu
10. cppc_cpufreq_get_transition_delay_us
11. cppc_cpufreq_get_transition_delay_us
12. cppc_cpufreq_cpu_init
13. get_delta
14. cppc_get_rate_from_fbctrs
15. cppc_cpufreq_get_rate
16. cppc_cpufreq_init
17. cppc_cpufreq_exit

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