drivers/acpi/cppc_acpi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * CPPC (Collaborative Processor Performance Control) methods used by CPUfreq drivers.
   4  *
   5  * (C) Copyright 2014, 2015 Linaro Ltd.
   6  * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
   7  *
   8  * CPPC describes a few methods for controlling CPU performance using
   9  * information from a per CPU table called CPC. This table is described in
  10  * the ACPI v5.0+ specification. The table consists of a list of
  11  * registers which may be memory mapped or hardware registers and also may
  12  * include some static integer values.
  13  *
  14  * CPU performance is on an abstract continuous scale as against a discretized
  15  * P-state scale which is tied to CPU frequency only. In brief, the basic
  16  * operation involves:
  17  *
  18  * - OS makes a CPU performance request. (Can provide min and max bounds)
  19  *
  20  * - Platform (such as BMC) is free to optimize request within requested bounds
  21  *   depending on power/thermal budgets etc.
  22  *
  23  * - Platform conveys its decision back to OS
  24  *
  25  * The communication between OS and platform occurs through another medium
  26  * called (PCC) Platform Communication Channel. This is a generic mailbox like
  27  * mechanism which includes doorbell semantics to indicate register updates.
  28  * See drivers/mailbox/pcc.c for details on PCC.
  29  *
  30  * Finer details about the PCC and CPPC spec are available in the ACPI v5.1 and
  31  * above specifications.
  32  */
  33
  34 #define pr_fmt(fmt)     "ACPI CPPC: " fmt
  35
  36 #include <linux/delay.h>
  37 #include <linux/iopoll.h>
  38 #include <linux/ktime.h>
  39 #include <linux/rwsem.h>
  40 #include <linux/wait.h>
  41 #include <linux/topology.h>
  42
  43 #include <acpi/cppc_acpi.h>
  44
  45 struct cppc_pcc_data {
  46         struct pcc_mbox_chan *pcc_channel;
  47         void __iomem *pcc_comm_addr;
  48         bool pcc_channel_acquired;
  49         unsigned int deadline_us;
  50         unsigned int pcc_mpar, pcc_mrtt, pcc_nominal;
  51
  52         bool pending_pcc_write_cmd;     /* Any pending/batched PCC write cmds? */
  53         bool platform_owns_pcc;         /* Ownership of PCC subspace */
  54         unsigned int pcc_write_cnt;     /* Running count of PCC write commands */
  55
  56         /*
  57          * Lock to provide controlled access to the PCC channel.
  58          *
  59          * For performance critical usecases(currently cppc_set_perf)
  60          *      We need to take read_lock and check if channel belongs to OSPM
  61          * before reading or writing to PCC subspace
  62          *      We need to take write_lock before transferring the channel
  63          * ownership to the platform via a Doorbell
  64          *      This allows us to batch a number of CPPC requests if they happen
  65          * to originate in about the same time
  66          *
  67          * For non-performance critical usecases(init)
  68          *      Take write_lock for all purposes which gives exclusive access
  69          */
  70         struct rw_semaphore pcc_lock;
  71
  72         /* Wait queue for CPUs whose requests were batched */
  73         wait_queue_head_t pcc_write_wait_q;
  74         ktime_t last_cmd_cmpl_time;
  75         ktime_t last_mpar_reset;
  76         int mpar_count;
  77         int refcount;
  78 };
  79
  80 /* Array to represent the PCC channel per subspace ID */
  81 static struct cppc_pcc_data *pcc_data[MAX_PCC_SUBSPACES];
  82 /* The cpu_pcc_subspace_idx contains per CPU subspace ID */
  83 static DEFINE_PER_CPU(int, cpu_pcc_subspace_idx);
  84
  85 /*
  86  * The cpc_desc structure contains the ACPI register details
  87  * as described in the per CPU _CPC tables. The details
  88  * include the type of register (e.g. PCC, System IO, FFH etc.)
  89  * and destination addresses which lets us READ/WRITE CPU performance
  90  * information using the appropriate I/O methods.
  91  */
  92 static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
  93
  94 /* pcc mapped address + header size + offset within PCC subspace */
  95 #define GET_PCC_VADDR(offs, pcc_ss_id) (pcc_data[pcc_ss_id]->pcc_comm_addr + \
  96                                                 0x8 + (offs))
  97
  98 /* Check if a CPC register is in PCC */
  99 #define CPC_IN_PCC(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&             \
 100                                 (cpc)->cpc_entry.reg.space_id ==        \
 101                                 ACPI_ADR_SPACE_PLATFORM_COMM)
 102
 103 /* Evaluates to True if reg is a NULL register descriptor */
 104 #define IS_NULL_REG(reg) ((reg)->space_id ==  ACPI_ADR_SPACE_SYSTEM_MEMORY && \
 105                                 (reg)->address == 0 &&                  \
 106                                 (reg)->bit_width == 0 &&                \
 107                                 (reg)->bit_offset == 0 &&               \
 108                                 (reg)->access_width == 0)
 109
 110 /* Evaluates to True if an optional cpc field is supported */
 111 #define CPC_SUPPORTED(cpc) ((cpc)->type == ACPI_TYPE_INTEGER ?          \
 112                                 !!(cpc)->cpc_entry.int_value :          \
 113                                 !IS_NULL_REG(&(cpc)->cpc_entry.reg))
 114 /*
 115  * Arbitrary Retries in case the remote processor is slow to respond
 116  * to PCC commands. Keeping it high enough to cover emulators where
 117  * the processors run painfully slow.
 118  */
 119 #define NUM_RETRIES 500ULL
 120
 121 #define OVER_16BTS_MASK ~0xFFFFULL
 122
 123 #define define_one_cppc_ro(_name)               \
 124 static struct kobj_attribute _name =            \
 125 __ATTR(_name, 0444, show_##_name, NULL)
 126
 127 #define to_cpc_desc(a) container_of(a, struct cpc_desc, kobj)
 128
 129 #define show_cppc_data(access_fn, struct_name, member_name)             \
 130         static ssize_t show_##member_name(struct kobject *kobj,         \
 131                                 struct kobj_attribute *attr, char *buf) \
 132         {                                                               \
 133                 struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);           \
 134                 struct struct_name st_name = {0};                       \
 135                 int ret;                                                \
 136                                                                         \
 137                 ret = access_fn(cpc_ptr->cpu_id, &st_name);             \
 138                 if (ret)                                                \
 139                         return ret;                                     \
 140                                                                         \
 141                 return scnprintf(buf, PAGE_SIZE, "%llu\n",              \
 142                                 (u64)st_name.member_name);              \
 143         }                                                               \
 144         define_one_cppc_ro(member_name)
 145
 146 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, highest_perf);
 147 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_perf);
 148 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_perf);
 149 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_nonlinear_perf);
 150 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_freq);
 151 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);
 152
 153 show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf);
 154 show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
 155
 156 static ssize_t show_feedback_ctrs(struct kobject *kobj,
 157                 struct kobj_attribute *attr, char *buf)
 158 {
 159         struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);
 160         struct cppc_perf_fb_ctrs fb_ctrs = {0};
 161         int ret;
 162
 163         ret = cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
 164         if (ret)
 165                 return ret;
 166
 167         return scnprintf(buf, PAGE_SIZE, "ref:%llu del:%llu\n",
 168                         fb_ctrs.reference, fb_ctrs.delivered);
 169 }
 170 define_one_cppc_ro(feedback_ctrs);
 171
 172 static struct attribute *cppc_attrs[] = {
 173         &feedback_ctrs.attr,
 174         &reference_perf.attr,
 175         &wraparound_time.attr,
 176         &highest_perf.attr,
 177         &lowest_perf.attr,
 178         &lowest_nonlinear_perf.attr,
 179         &nominal_perf.attr,
 180         &nominal_freq.attr,
 181         &lowest_freq.attr,
 182         NULL
 183 };
 184 ATTRIBUTE_GROUPS(cppc);
 185
 186 static struct kobj_type cppc_ktype = {
 187         .sysfs_ops = &kobj_sysfs_ops,
 188         .default_groups = cppc_groups,
 189 };
 190
 191 static int check_pcc_chan(int pcc_ss_id, bool chk_err_bit)
 192 {
 193         int ret, status;
 194         struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
 195         struct acpi_pcct_shared_memory __iomem *generic_comm_base =
 196                 pcc_ss_data->pcc_comm_addr;
 197
 198         if (!pcc_ss_data->platform_owns_pcc)
 199                 return 0;
 200
 201         /*
 202          * Poll PCC status register every 3us(delay_us) for maximum of
 203          * deadline_us(timeout_us) until PCC command complete bit is set(cond)
 204          */
 205         ret = readw_relaxed_poll_timeout(&generic_comm_base->status, status,
 206                                         status & PCC_CMD_COMPLETE_MASK, 3,
 207                                         pcc_ss_data->deadline_us);
 208
 209         if (likely(!ret)) {
 210                 pcc_ss_data->platform_owns_pcc = false;
 211                 if (chk_err_bit && (status & PCC_ERROR_MASK))
 212                         ret = -EIO;
 213         }
 214
 215         if (unlikely(ret))
 216                 pr_err("PCC check channel failed for ss: %d. ret=%d\n",
 217                        pcc_ss_id, ret);
 218
 219         return ret;
 220 }
 221
 222 /*
 223  * This function transfers the ownership of the PCC to the platform
 224  * So it must be called while holding write_lock(pcc_lock)
 225  */
 226 static int send_pcc_cmd(int pcc_ss_id, u16 cmd)
 227 {
 228         int ret = -EIO, i;
 229         struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
 230         struct acpi_pcct_shared_memory __iomem *generic_comm_base =
 231                 pcc_ss_data->pcc_comm_addr;
 232         unsigned int time_delta;
 233
 234         /*
 235          * For CMD_WRITE we know for a fact the caller should have checked
 236          * the channel before writing to PCC space
 237          */
 238         if (cmd == CMD_READ) {
 239                 /*
 240                  * If there are pending cpc_writes, then we stole the channel
 241                  * before write completion, so first send a WRITE command to
 242                  * platform
 243                  */
 244                 if (pcc_ss_data->pending_pcc_write_cmd)
 245                         send_pcc_cmd(pcc_ss_id, CMD_WRITE);
 246
 247                 ret = check_pcc_chan(pcc_ss_id, false);
 248                 if (ret)
 249                         goto end;
 250         } else /* CMD_WRITE */
 251                 pcc_ss_data->pending_pcc_write_cmd = FALSE;
 252
 253         /*
 254          * Handle the Minimum Request Turnaround Time(MRTT)
 255          * "The minimum amount of time that OSPM must wait after the completion
 256          * of a command before issuing the next command, in microseconds"
 257          */
 258         if (pcc_ss_data->pcc_mrtt) {
 259                 time_delta = ktime_us_delta(ktime_get(),
 260                                             pcc_ss_data->last_cmd_cmpl_time);
 261                 if (pcc_ss_data->pcc_mrtt > time_delta)
 262                         udelay(pcc_ss_data->pcc_mrtt - time_delta);
 263         }
 264
 265         /*
 266          * Handle the non-zero Maximum Periodic Access Rate(MPAR)
 267          * "The maximum number of periodic requests that the subspace channel can
 268          * support, reported in commands per minute. 0 indicates no limitation."
 269          *
 270          * This parameter should be ideally zero or large enough so that it can
 271          * handle maximum number of requests that all the cores in the system can
 272          * collectively generate. If it is not, we will follow the spec and just
 273          * not send the request to the platform after hitting the MPAR limit in
 274          * any 60s window
 275          */
 276         if (pcc_ss_data->pcc_mpar) {
 277                 if (pcc_ss_data->mpar_count == 0) {
 278                         time_delta = ktime_ms_delta(ktime_get(),
 279                                                     pcc_ss_data->last_mpar_reset);
 280                         if ((time_delta < 60 * MSEC_PER_SEC) && pcc_ss_data->last_mpar_reset) {
 281                                 pr_debug("PCC cmd for subspace %d not sent due to MPAR limit",
 282                                          pcc_ss_id);
 283                                 ret = -EIO;
 284                                 goto end;
 285                         }
 286                         pcc_ss_data->last_mpar_reset = ktime_get();
 287                         pcc_ss_data->mpar_count = pcc_ss_data->pcc_mpar;
 288                 }
 289                 pcc_ss_data->mpar_count--;
 290         }
 291
 292         /* Write to the shared comm region. */
 293         writew_relaxed(cmd, &generic_comm_base->command);
 294
 295         /* Flip CMD COMPLETE bit */
 296         writew_relaxed(0, &generic_comm_base->status);
 297
 298         pcc_ss_data->platform_owns_pcc = true;
 299
 300         /* Ring doorbell */
 301         ret = mbox_send_message(pcc_ss_data->pcc_channel->mchan, &cmd);
 302         if (ret < 0) {
 303                 pr_err("Err sending PCC mbox message. ss: %d cmd:%d, ret:%d\n",
 304                        pcc_ss_id, cmd, ret);
 305                 goto end;
 306         }
 307
 308         /* wait for completion and check for PCC errro bit */
 309         ret = check_pcc_chan(pcc_ss_id, true);
 310
 311         if (pcc_ss_data->pcc_mrtt)
 312                 pcc_ss_data->last_cmd_cmpl_time = ktime_get();
 313
 314         if (pcc_ss_data->pcc_channel->mchan->mbox->txdone_irq)
 315                 mbox_chan_txdone(pcc_ss_data->pcc_channel->mchan, ret);
 316         else
 317                 mbox_client_txdone(pcc_ss_data->pcc_channel->mchan, ret);
 318
 319 end:
 320         if (cmd == CMD_WRITE) {
 321                 if (unlikely(ret)) {
 322                         for_each_possible_cpu(i) {
 323                                 struct cpc_desc *desc = per_cpu(cpc_desc_ptr, i);
 324
 325                                 if (!desc)
 326                                         continue;
 327
 328                                 if (desc->write_cmd_id == pcc_ss_data->pcc_write_cnt)
 329                                         desc->write_cmd_status = ret;
 330                         }
 331                 }
 332                 pcc_ss_data->pcc_write_cnt++;
 333                 wake_up_all(&pcc_ss_data->pcc_write_wait_q);
 334         }
 335
 336         return ret;
 337 }
 338
 339 static void cppc_chan_tx_done(struct mbox_client *cl, void *msg, int ret)
 340 {
 341         if (ret < 0)
 342                 pr_debug("TX did not complete: CMD sent:%x, ret:%d\n",
 343                                 *(u16 *)msg, ret);
 344         else
 345                 pr_debug("TX completed. CMD sent:%x, ret:%d\n",
 346                                 *(u16 *)msg, ret);
 347 }
 348
 349 static struct mbox_client cppc_mbox_cl = {
 350         .tx_done = cppc_chan_tx_done,
 351         .knows_txdone = true,
 352 };
 353
 354 static int acpi_get_psd(struct cpc_desc *cpc_ptr, acpi_handle handle)
 355 {
 356         int result = -EFAULT;
 357         acpi_status status = AE_OK;
 358         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 359         struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
 360         struct acpi_buffer state = {0, NULL};
 361         union acpi_object  *psd = NULL;
 362         struct acpi_psd_package *pdomain;
 363
 364         status = acpi_evaluate_object_typed(handle, "_PSD", NULL,
 365                                             &buffer, ACPI_TYPE_PACKAGE);
 366         if (status == AE_NOT_FOUND)     /* _PSD is optional */
 367                 return 0;
 368         if (ACPI_FAILURE(status))
 369                 return -ENODEV;
 370
 371         psd = buffer.pointer;
 372         if (!psd || psd->package.count != 1) {
 373                 pr_debug("Invalid _PSD data\n");
 374                 goto end;
 375         }
 376
 377         pdomain = &(cpc_ptr->domain_info);
 378
 379         state.length = sizeof(struct acpi_psd_package);
 380         state.pointer = pdomain;
 381
 382         status = acpi_extract_package(&(psd->package.elements[0]),
 383                 &format, &state);
 384         if (ACPI_FAILURE(status)) {
 385                 pr_debug("Invalid _PSD data for CPU:%d\n", cpc_ptr->cpu_id);
 386                 goto end;
 387         }
 388
 389         if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
 390                 pr_debug("Unknown _PSD:num_entries for CPU:%d\n", cpc_ptr->cpu_id);
 391                 goto end;
 392         }
 393
 394         if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
 395                 pr_debug("Unknown _PSD:revision for CPU: %d\n", cpc_ptr->cpu_id);
 396                 goto end;
 397         }
 398
 399         if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
 400             pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
 401             pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
 402                 pr_debug("Invalid _PSD:coord_type for CPU:%d\n", cpc_ptr->cpu_id);
 403                 goto end;
 404         }
 405
 406         result = 0;
 407 end:
 408         kfree(buffer.pointer);
 409         return result;
 410 }
 411
 412 bool acpi_cpc_valid(void)
 413 {
 414         struct cpc_desc *cpc_ptr;
 415         int cpu;
 416
 417         for_each_present_cpu(cpu) {
 418                 cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 419                 if (!cpc_ptr)
 420                         return false;
 421         }
 422
 423         return true;
 424 }
 425 EXPORT_SYMBOL_GPL(acpi_cpc_valid);
 426
 427 /**
 428  * acpi_get_psd_map - Map the CPUs in the freq domain of a given cpu
 429  * @cpu: Find all CPUs that share a domain with cpu.
 430  * @cpu_data: Pointer to CPU specific CPPC data including PSD info.
 431  *
 432  *      Return: 0 for success or negative value for err.
 433  */
 434 int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data)
 435 {
 436         struct cpc_desc *cpc_ptr, *match_cpc_ptr;
 437         struct acpi_psd_package *match_pdomain;
 438         struct acpi_psd_package *pdomain;
 439         int count_target, i;
 440
 441         /*
 442          * Now that we have _PSD data from all CPUs, let's setup P-state
 443          * domain info.
 444          */
 445         cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 446         if (!cpc_ptr)
 447                 return -EFAULT;
 448
 449         pdomain = &(cpc_ptr->domain_info);
 450         cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
 451         if (pdomain->num_processors <= 1)
 452                 return 0;
 453
 454         /* Validate the Domain info */
 455         count_target = pdomain->num_processors;
 456         if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
 457                 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 458         else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
 459                 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_HW;
 460         else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
 461                 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 462
 463         for_each_possible_cpu(i) {
 464                 if (i == cpu)
 465                         continue;
 466
 467                 match_cpc_ptr = per_cpu(cpc_desc_ptr, i);
 468                 if (!match_cpc_ptr)
 469                         goto err_fault;
 470
 471                 match_pdomain = &(match_cpc_ptr->domain_info);
 472                 if (match_pdomain->domain != pdomain->domain)
 473                         continue;
 474
 475                 /* Here i and cpu are in the same domain */
 476                 if (match_pdomain->num_processors != count_target)
 477                         goto err_fault;
 478
 479                 if (pdomain->coord_type != match_pdomain->coord_type)
 480                         goto err_fault;
 481
 482                 cpumask_set_cpu(i, cpu_data->shared_cpu_map);
 483         }
 484
 485         return 0;
 486
 487 err_fault:
 488         /* Assume no coordination on any error parsing domain info */
 489         cpumask_clear(cpu_data->shared_cpu_map);
 490         cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
 491         cpu_data->shared_type = CPUFREQ_SHARED_TYPE_NONE;
 492
 493         return -EFAULT;
 494 }
 495 EXPORT_SYMBOL_GPL(acpi_get_psd_map);
 496
 497 static int register_pcc_channel(int pcc_ss_idx)
 498 {
 499         struct pcc_mbox_chan *pcc_chan;
 500         u64 usecs_lat;
 501
 502         if (pcc_ss_idx >= 0) {
 503                 pcc_chan = pcc_mbox_request_channel(&cppc_mbox_cl, pcc_ss_idx);
 504
 505                 if (IS_ERR(pcc_chan)) {
 506                         pr_err("Failed to find PCC channel for subspace %d\n",
 507                                pcc_ss_idx);
 508                         return -ENODEV;
 509                 }
 510
 511                 pcc_data[pcc_ss_idx]->pcc_channel = pcc_chan;
 512                 /*
 513                  * cppc_ss->latency is just a Nominal value. In reality
 514                  * the remote processor could be much slower to reply.
 515                  * So add an arbitrary amount of wait on top of Nominal.
 516                  */
 517                 usecs_lat = NUM_RETRIES * pcc_chan->latency;
 518                 pcc_data[pcc_ss_idx]->deadline_us = usecs_lat;
 519                 pcc_data[pcc_ss_idx]->pcc_mrtt = pcc_chan->min_turnaround_time;
 520                 pcc_data[pcc_ss_idx]->pcc_mpar = pcc_chan->max_access_rate;
 521                 pcc_data[pcc_ss_idx]->pcc_nominal = pcc_chan->latency;
 522
 523                 pcc_data[pcc_ss_idx]->pcc_comm_addr =
 524                         acpi_os_ioremap(pcc_chan->shmem_base_addr,
 525                                         pcc_chan->shmem_size);
 526                 if (!pcc_data[pcc_ss_idx]->pcc_comm_addr) {
 527                         pr_err("Failed to ioremap PCC comm region mem for %d\n",
 528                                pcc_ss_idx);
 529                         return -ENOMEM;
 530                 }
 531
 532                 /* Set flag so that we don't come here for each CPU. */
 533                 pcc_data[pcc_ss_idx]->pcc_channel_acquired = true;
 534         }
 535
 536         return 0;
 537 }
 538
 539 /**
 540  * cpc_ffh_supported() - check if FFH reading supported
 541  *
 542  * Check if the architecture has support for functional fixed hardware
 543  * read/write capability.
 544  *
 545  * Return: true for supported, false for not supported
 546  */
 547 bool __weak cpc_ffh_supported(void)
 548 {
 549         return false;
 550 }
 551
 552 /**
 553  * pcc_data_alloc() - Allocate the pcc_data memory for pcc subspace
 554  *
 555  * Check and allocate the cppc_pcc_data memory.
 556  * In some processor configurations it is possible that same subspace
 557  * is shared between multiple CPUs. This is seen especially in CPUs
 558  * with hardware multi-threading support.
 559  *
 560  * Return: 0 for success, errno for failure
 561  */
 562 static int pcc_data_alloc(int pcc_ss_id)
 563 {
 564         if (pcc_ss_id < 0 || pcc_ss_id >= MAX_PCC_SUBSPACES)
 565                 return -EINVAL;
 566
 567         if (pcc_data[pcc_ss_id]) {
 568                 pcc_data[pcc_ss_id]->refcount++;
 569         } else {
 570                 pcc_data[pcc_ss_id] = kzalloc(sizeof(struct cppc_pcc_data),
 571                                               GFP_KERNEL);
 572                 if (!pcc_data[pcc_ss_id])
 573                         return -ENOMEM;
 574                 pcc_data[pcc_ss_id]->refcount++;
 575         }
 576
 577         return 0;
 578 }
 579
 580 /* Check if CPPC revision + num_ent combination is supported */
 581 static bool is_cppc_supported(int revision, int num_ent)
 582 {
 583         int expected_num_ent;
 584
 585         switch (revision) {
 586         case CPPC_V2_REV:
 587                 expected_num_ent = CPPC_V2_NUM_ENT;
 588                 break;
 589         case CPPC_V3_REV:
 590                 expected_num_ent = CPPC_V3_NUM_ENT;
 591                 break;
 592         default:
 593                 pr_debug("Firmware exports unsupported CPPC revision: %d\n",
 594                         revision);
 595                 return false;
 596         }
 597
 598         if (expected_num_ent != num_ent) {
 599                 pr_debug("Firmware exports %d entries. Expected: %d for CPPC rev:%d\n",
 600                         num_ent, expected_num_ent, revision);
 601                 return false;
 602         }
 603
 604         return true;
 605 }
 606
 607 /*
 608  * An example CPC table looks like the following.
 609  *
 610  *  Name (_CPC, Package() {
 611  *      17,                                                     // NumEntries
 612  *      1,                                                      // Revision
 613  *      ResourceTemplate() {Register(PCC, 32, 0, 0x120, 2)},    // Highest Performance
 614  *      ResourceTemplate() {Register(PCC, 32, 0, 0x124, 2)},    // Nominal Performance
 615  *      ResourceTemplate() {Register(PCC, 32, 0, 0x128, 2)},    // Lowest Nonlinear Performance
 616  *      ResourceTemplate() {Register(PCC, 32, 0, 0x12C, 2)},    // Lowest Performance
 617  *      ResourceTemplate() {Register(PCC, 32, 0, 0x130, 2)},    // Guaranteed Performance Register
 618  *      ResourceTemplate() {Register(PCC, 32, 0, 0x110, 2)},    // Desired Performance Register
 619  *      ResourceTemplate() {Register(SystemMemory, 0, 0, 0, 0)},
 620  *      ...
 621  *      ...
 622  *      ...
 623  *  }
 624  * Each Register() encodes how to access that specific register.
 625  * e.g. a sample PCC entry has the following encoding:
 626  *
 627  *  Register (
 628  *      PCC,    // AddressSpaceKeyword
 629  *      8,      // RegisterBitWidth
 630  *      8,      // RegisterBitOffset
 631  *      0x30,   // RegisterAddress
 632  *      9,      // AccessSize (subspace ID)
 633  *  )
 634  */
 635
 636 #ifndef arch_init_invariance_cppc
 637 static inline void arch_init_invariance_cppc(void) { }
 638 #endif
 639
 640 /**
 641  * acpi_cppc_processor_probe - Search for per CPU _CPC objects.
 642  * @pr: Ptr to acpi_processor containing this CPU's logical ID.
 643  *
 644  *      Return: 0 for success or negative value for err.
 645  */
 646 int acpi_cppc_processor_probe(struct acpi_processor *pr)
 647 {
 648         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 649         union acpi_object *out_obj, *cpc_obj;
 650         struct cpc_desc *cpc_ptr;
 651         struct cpc_reg *gas_t;
 652         struct device *cpu_dev;
 653         acpi_handle handle = pr->handle;
 654         unsigned int num_ent, i, cpc_rev;
 655         int pcc_subspace_id = -1;
 656         acpi_status status;
 657         int ret = -EFAULT;
 658
 659         if (osc_sb_cppc_not_supported)
 660                 return -ENODEV;
 661
 662         /* Parse the ACPI _CPC table for this CPU. */
 663         status = acpi_evaluate_object_typed(handle, "_CPC", NULL, &output,
 664                         ACPI_TYPE_PACKAGE);
 665         if (ACPI_FAILURE(status)) {
 666                 ret = -ENODEV;
 667                 goto out_buf_free;
 668         }
 669
 670         out_obj = (union acpi_object *) output.pointer;
 671
 672         cpc_ptr = kzalloc(sizeof(struct cpc_desc), GFP_KERNEL);
 673         if (!cpc_ptr) {
 674                 ret = -ENOMEM;
 675                 goto out_buf_free;
 676         }
 677
 678         /* First entry is NumEntries. */
 679         cpc_obj = &out_obj->package.elements[0];
 680         if (cpc_obj->type == ACPI_TYPE_INTEGER) {
 681                 num_ent = cpc_obj->integer.value;
 682         } else {
 683                 pr_debug("Unexpected entry type(%d) for NumEntries\n",
 684                                 cpc_obj->type);
 685                 goto out_free;
 686         }
 687         cpc_ptr->num_entries = num_ent;
 688
 689         /* Second entry should be revision. */
 690         cpc_obj = &out_obj->package.elements[1];
 691         if (cpc_obj->type == ACPI_TYPE_INTEGER) {
 692                 cpc_rev = cpc_obj->integer.value;
 693         } else {
 694                 pr_debug("Unexpected entry type(%d) for Revision\n",
 695                                 cpc_obj->type);
 696                 goto out_free;
 697         }
 698         cpc_ptr->version = cpc_rev;
 699
 700         if (!is_cppc_supported(cpc_rev, num_ent))
 701                 goto out_free;
 702
 703         /* Iterate through remaining entries in _CPC */
 704         for (i = 2; i < num_ent; i++) {
 705                 cpc_obj = &out_obj->package.elements[i];
 706
 707                 if (cpc_obj->type == ACPI_TYPE_INTEGER) {
 708                         cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_INTEGER;
 709                         cpc_ptr->cpc_regs[i-2].cpc_entry.int_value = cpc_obj->integer.value;
 710                 } else if (cpc_obj->type == ACPI_TYPE_BUFFER) {
 711                         gas_t = (struct cpc_reg *)
 712                                 cpc_obj->buffer.pointer;
 713
 714                         /*
 715                          * The PCC Subspace index is encoded inside
 716                          * the CPC table entries. The same PCC index
 717                          * will be used for all the PCC entries,
 718                          * so extract it only once.
 719                          */
 720                         if (gas_t->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
 721                                 if (pcc_subspace_id < 0) {
 722                                         pcc_subspace_id = gas_t->access_width;
 723                                         if (pcc_data_alloc(pcc_subspace_id))
 724                                                 goto out_free;
 725                                 } else if (pcc_subspace_id != gas_t->access_width) {
 726                                         pr_debug("Mismatched PCC ids.\n");
 727                                         goto out_free;
 728                                 }
 729                         } else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 730                                 if (gas_t->address) {
 731                                         void __iomem *addr;
 732
 733                                         addr = ioremap(gas_t->address, gas_t->bit_width/8);
 734                                         if (!addr)
 735                                                 goto out_free;
 736                                         cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
 737                                 }
 738                         } else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
 739                                 if (gas_t->access_width < 1 || gas_t->access_width > 3) {
 740                                         /*
 741                                          * 1 = 8-bit, 2 = 16-bit, and 3 = 32-bit.
 742                                          * SystemIO doesn't implement 64-bit
 743                                          * registers.
 744                                          */
 745                                         pr_debug("Invalid access width %d for SystemIO register\n",
 746                                                 gas_t->access_width);
 747                                         goto out_free;
 748                                 }
 749                                 if (gas_t->address & OVER_16BTS_MASK) {
 750                                         /* SystemIO registers use 16-bit integer addresses */
 751                                         pr_debug("Invalid IO port %llu for SystemIO register\n",
 752                                                 gas_t->address);
 753                                         goto out_free;
 754                                 }
 755                         } else {
 756                                 if (gas_t->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE || !cpc_ffh_supported()) {
 757                                         /* Support only PCC, SystemMemory, SystemIO, and FFH type regs. */
 758                                         pr_debug("Unsupported register type: %d\n", gas_t->space_id);
 759                                         goto out_free;
 760                                 }
 761                         }
 762
 763                         cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_BUFFER;
 764                         memcpy(&cpc_ptr->cpc_regs[i-2].cpc_entry.reg, gas_t, sizeof(*gas_t));
 765                 } else {
 766                         pr_debug("Err in entry:%d in CPC table of CPU:%d\n", i, pr->id);
 767                         goto out_free;
 768                 }
 769         }
 770         per_cpu(cpu_pcc_subspace_idx, pr->id) = pcc_subspace_id;
 771
 772         /*
 773          * Initialize the remaining cpc_regs as unsupported.
 774          * Example: In case FW exposes CPPC v2, the below loop will initialize
 775          * LOWEST_FREQ and NOMINAL_FREQ regs as unsupported
 776          */
 777         for (i = num_ent - 2; i < MAX_CPC_REG_ENT; i++) {
 778                 cpc_ptr->cpc_regs[i].type = ACPI_TYPE_INTEGER;
 779                 cpc_ptr->cpc_regs[i].cpc_entry.int_value = 0;
 780         }
 781
 782
 783         /* Store CPU Logical ID */
 784         cpc_ptr->cpu_id = pr->id;
 785
 786         /* Parse PSD data for this CPU */
 787         ret = acpi_get_psd(cpc_ptr, handle);
 788         if (ret)
 789                 goto out_free;
 790
 791         /* Register PCC channel once for all PCC subspace ID. */
 792         if (pcc_subspace_id >= 0 && !pcc_data[pcc_subspace_id]->pcc_channel_acquired) {
 793                 ret = register_pcc_channel(pcc_subspace_id);
 794                 if (ret)
 795                         goto out_free;
 796
 797                 init_rwsem(&pcc_data[pcc_subspace_id]->pcc_lock);
 798                 init_waitqueue_head(&pcc_data[pcc_subspace_id]->pcc_write_wait_q);
 799         }
 800
 801         /* Everything looks okay */
 802         pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);
 803
 804         /* Add per logical CPU nodes for reading its feedback counters. */
 805         cpu_dev = get_cpu_device(pr->id);
 806         if (!cpu_dev) {
 807                 ret = -EINVAL;
 808                 goto out_free;
 809         }
 810
 811         /* Plug PSD data into this CPU's CPC descriptor. */
 812         per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
 813
 814         ret = kobject_init_and_add(&cpc_ptr->kobj, &cppc_ktype, &cpu_dev->kobj,
 815                         "acpi_cppc");
 816         if (ret) {
 817                 per_cpu(cpc_desc_ptr, pr->id) = NULL;
 818                 kobject_put(&cpc_ptr->kobj);
 819                 goto out_free;
 820         }
 821
 822         arch_init_invariance_cppc();
 823
 824         kfree(output.pointer);
 825         return 0;
 826
 827 out_free:
 828         /* Free all the mapped sys mem areas for this CPU */
 829         for (i = 2; i < cpc_ptr->num_entries; i++) {
 830                 void __iomem *addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
 831
 832                 if (addr)
 833                         iounmap(addr);
 834         }
 835         kfree(cpc_ptr);
 836
 837 out_buf_free:
 838         kfree(output.pointer);
 839         return ret;
 840 }
 841 EXPORT_SYMBOL_GPL(acpi_cppc_processor_probe);
 842
 843 /**
 844  * acpi_cppc_processor_exit - Cleanup CPC structs.
 845  * @pr: Ptr to acpi_processor containing this CPU's logical ID.
 846  *
 847  * Return: Void
 848  */
 849 void acpi_cppc_processor_exit(struct acpi_processor *pr)
 850 {
 851         struct cpc_desc *cpc_ptr;
 852         unsigned int i;
 853         void __iomem *addr;
 854         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, pr->id);
 855
 856         if (pcc_ss_id >= 0 && pcc_data[pcc_ss_id]) {
 857                 if (pcc_data[pcc_ss_id]->pcc_channel_acquired) {
 858                         pcc_data[pcc_ss_id]->refcount--;
 859                         if (!pcc_data[pcc_ss_id]->refcount) {
 860                                 pcc_mbox_free_channel(pcc_data[pcc_ss_id]->pcc_channel);
 861                                 kfree(pcc_data[pcc_ss_id]);
 862                                 pcc_data[pcc_ss_id] = NULL;
 863                         }
 864                 }
 865         }
 866
 867         cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
 868         if (!cpc_ptr)
 869                 return;
 870
 871         /* Free all the mapped sys mem areas for this CPU */
 872         for (i = 2; i < cpc_ptr->num_entries; i++) {
 873                 addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
 874                 if (addr)
 875                         iounmap(addr);
 876         }
 877
 878         kobject_put(&cpc_ptr->kobj);
 879         kfree(cpc_ptr);
 880 }
 881 EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
 882
 883 /**
 884  * cpc_read_ffh() - Read FFH register
 885  * @cpunum:     CPU number to read
 886  * @reg:        cppc register information
 887  * @val:        place holder for return value
 888  *
 889  * Read bit_width bits from a specified address and bit_offset
 890  *
 891  * Return: 0 for success and error code
 892  */
 893 int __weak cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
 894 {
 895         return -ENOTSUPP;
 896 }
 897
 898 /**
 899  * cpc_write_ffh() - Write FFH register
 900  * @cpunum:     CPU number to write
 901  * @reg:        cppc register information
 902  * @val:        value to write
 903  *
 904  * Write value of bit_width bits to a specified address and bit_offset
 905  *
 906  * Return: 0 for success and error code
 907  */
 908 int __weak cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
 909 {
 910         return -ENOTSUPP;
 911 }
 912
 913 /*
 914  * Since cpc_read and cpc_write are called while holding pcc_lock, it should be
 915  * as fast as possible. We have already mapped the PCC subspace during init, so
 916  * we can directly write to it.
 917  */
 918
 919 static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 920 {
 921         void __iomem *vaddr = NULL;
 922         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
 923         struct cpc_reg *reg = &reg_res->cpc_entry.reg;
 924
 925         if (reg_res->type == ACPI_TYPE_INTEGER) {
 926                 *val = reg_res->cpc_entry.int_value;
 927                 return 0;
 928         }
 929
 930         *val = 0;
 931
 932         if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
 933                 u32 width = 8 << (reg->access_width - 1);
 934                 u32 val_u32;
 935                 acpi_status status;
 936
 937                 status = acpi_os_read_port((acpi_io_address)reg->address,
 938                                            &val_u32, width);
 939                 if (ACPI_FAILURE(status)) {
 940                         pr_debug("Error: Failed to read SystemIO port %llx\n",
 941                                  reg->address);
 942                         return -EFAULT;
 943                 }
 944
 945                 *val = val_u32;
 946                 return 0;
 947         } else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
 948                 vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
 949         else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
 950                 vaddr = reg_res->sys_mem_vaddr;
 951         else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
 952                 return cpc_read_ffh(cpu, reg, val);
 953         else
 954                 return acpi_os_read_memory((acpi_physical_address)reg->address,
 955                                 val, reg->bit_width);
 956
 957         switch (reg->bit_width) {
 958         case 8:
 959                 *val = readb_relaxed(vaddr);
 960                 break;
 961         case 16:
 962                 *val = readw_relaxed(vaddr);
 963                 break;
 964         case 32:
 965                 *val = readl_relaxed(vaddr);
 966                 break;
 967         case 64:
 968                 *val = readq_relaxed(vaddr);
 969                 break;
 970         default:
 971                 pr_debug("Error: Cannot read %u bit width from PCC for ss: %d\n",
 972                          reg->bit_width, pcc_ss_id);
 973                 return -EFAULT;
 974         }
 975
 976         return 0;
 977 }
 978
 979 static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 980 {
 981         int ret_val = 0;
 982         void __iomem *vaddr = NULL;
 983         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
 984         struct cpc_reg *reg = &reg_res->cpc_entry.reg;
 985
 986         if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
 987                 u32 width = 8 << (reg->access_width - 1);
 988                 acpi_status status;
 989
 990                 status = acpi_os_write_port((acpi_io_address)reg->address,
 991                                             (u32)val, width);
 992                 if (ACPI_FAILURE(status)) {
 993                         pr_debug("Error: Failed to write SystemIO port %llx\n",
 994                                  reg->address);
 995                         return -EFAULT;
 996                 }
 997
 998                 return 0;
 999         } else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
1000                 vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
1001         else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
1002                 vaddr = reg_res->sys_mem_vaddr;
1003         else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
1004                 return cpc_write_ffh(cpu, reg, val);
1005         else
1006                 return acpi_os_write_memory((acpi_physical_address)reg->address,
1007                                 val, reg->bit_width);
1008
1009         switch (reg->bit_width) {
1010         case 8:
1011                 writeb_relaxed(val, vaddr);
1012                 break;
1013         case 16:
1014                 writew_relaxed(val, vaddr);
1015                 break;
1016         case 32:
1017                 writel_relaxed(val, vaddr);
1018                 break;
1019         case 64:
1020                 writeq_relaxed(val, vaddr);
1021                 break;
1022         default:
1023                 pr_debug("Error: Cannot write %u bit width to PCC for ss: %d\n",
1024                          reg->bit_width, pcc_ss_id);
1025                 ret_val = -EFAULT;
1026                 break;
1027         }
1028
1029         return ret_val;
1030 }
1031
1032 static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
1033 {
1034         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1035         struct cpc_register_resource *reg;
1036
1037         if (!cpc_desc) {
1038                 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1039                 return -ENODEV;
1040         }
1041
1042         reg = &cpc_desc->cpc_regs[reg_idx];
1043
1044         if (CPC_IN_PCC(reg)) {
1045                 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1046                 struct cppc_pcc_data *pcc_ss_data = NULL;
1047                 int ret = 0;
1048
1049                 if (pcc_ss_id < 0)
1050                         return -EIO;
1051
1052                 pcc_ss_data = pcc_data[pcc_ss_id];
1053
1054                 down_write(&pcc_ss_data->pcc_lock);
1055
1056                 if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0)
1057                         cpc_read(cpunum, reg, perf);
1058                 else
1059                         ret = -EIO;
1060
1061                 up_write(&pcc_ss_data->pcc_lock);
1062
1063                 return ret;
1064         }
1065
1066         cpc_read(cpunum, reg, perf);
1067
1068         return 0;
1069 }
1070
1071 /**
1072  * cppc_get_desired_perf - Get the desired performance register value.
1073  * @cpunum: CPU from which to get desired performance.
1074  * @desired_perf: Return address.
1075  *
1076  * Return: 0 for success, -EIO otherwise.
1077  */
1078 int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
1079 {
1080         return cppc_get_perf(cpunum, DESIRED_PERF, desired_perf);
1081 }
1082 EXPORT_SYMBOL_GPL(cppc_get_desired_perf);
1083
1084 /**
1085  * cppc_get_nominal_perf - Get the nominal performance register value.
1086  * @cpunum: CPU from which to get nominal performance.
1087  * @nominal_perf: Return address.
1088  *
1089  * Return: 0 for success, -EIO otherwise.
1090  */
1091 int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
1092 {
1093         return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
1094 }
1095
1096 /**
1097  * cppc_get_perf_caps - Get a CPU's performance capabilities.
1098  * @cpunum: CPU from which to get capabilities info.
1099  * @perf_caps: ptr to cppc_perf_caps. See cppc_acpi.h
1100  *
1101  * Return: 0 for success with perf_caps populated else -ERRNO.
1102  */
1103 int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
1104 {
1105         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1106         struct cpc_register_resource *highest_reg, *lowest_reg,
1107                 *lowest_non_linear_reg, *nominal_reg, *guaranteed_reg,
1108                 *low_freq_reg = NULL, *nom_freq_reg = NULL;
1109         u64 high, low, guaranteed, nom, min_nonlinear, low_f = 0, nom_f = 0;
1110         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1111         struct cppc_pcc_data *pcc_ss_data = NULL;
1112         int ret = 0, regs_in_pcc = 0;
1113
1114         if (!cpc_desc) {
1115                 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1116                 return -ENODEV;
1117         }
1118
1119         highest_reg = &cpc_desc->cpc_regs[HIGHEST_PERF];
1120         lowest_reg = &cpc_desc->cpc_regs[LOWEST_PERF];
1121         lowest_non_linear_reg = &cpc_desc->cpc_regs[LOW_NON_LINEAR_PERF];
1122         nominal_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
1123         low_freq_reg = &cpc_desc->cpc_regs[LOWEST_FREQ];
1124         nom_freq_reg = &cpc_desc->cpc_regs[NOMINAL_FREQ];
1125         guaranteed_reg = &cpc_desc->cpc_regs[GUARANTEED_PERF];
1126
1127         /* Are any of the regs PCC ?*/
1128         if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
1129                 CPC_IN_PCC(lowest_non_linear_reg) || CPC_IN_PCC(nominal_reg) ||
1130                 CPC_IN_PCC(low_freq_reg) || CPC_IN_PCC(nom_freq_reg)) {
1131                 if (pcc_ss_id < 0) {
1132                         pr_debug("Invalid pcc_ss_id\n");
1133                         return -ENODEV;
1134                 }
1135                 pcc_ss_data = pcc_data[pcc_ss_id];
1136                 regs_in_pcc = 1;
1137                 down_write(&pcc_ss_data->pcc_lock);
1138                 /* Ring doorbell once to update PCC subspace */
1139                 if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
1140                         ret = -EIO;
1141                         goto out_err;
1142                 }
1143         }
1144
1145         cpc_read(cpunum, highest_reg, &high);
1146         perf_caps->highest_perf = high;
1147
1148         cpc_read(cpunum, lowest_reg, &low);
1149         perf_caps->lowest_perf = low;
1150
1151         cpc_read(cpunum, nominal_reg, &nom);
1152         perf_caps->nominal_perf = nom;
1153
1154         if (guaranteed_reg->type != ACPI_TYPE_BUFFER  ||
1155             IS_NULL_REG(&guaranteed_reg->cpc_entry.reg)) {
1156                 perf_caps->guaranteed_perf = 0;
1157         } else {
1158                 cpc_read(cpunum, guaranteed_reg, &guaranteed);
1159                 perf_caps->guaranteed_perf = guaranteed;
1160         }
1161
1162         cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear);
1163         perf_caps->lowest_nonlinear_perf = min_nonlinear;
1164
1165         if (!high || !low || !nom || !min_nonlinear)
1166                 ret = -EFAULT;
1167
1168         /* Read optional lowest and nominal frequencies if present */
1169         if (CPC_SUPPORTED(low_freq_reg))
1170                 cpc_read(cpunum, low_freq_reg, &low_f);
1171
1172         if (CPC_SUPPORTED(nom_freq_reg))
1173                 cpc_read(cpunum, nom_freq_reg, &nom_f);
1174
1175         perf_caps->lowest_freq = low_f;
1176         perf_caps->nominal_freq = nom_f;
1177
1178
1179 out_err:
1180         if (regs_in_pcc)
1181                 up_write(&pcc_ss_data->pcc_lock);
1182         return ret;
1183 }
1184 EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
1185
1186 /**
1187  * cppc_get_perf_ctrs - Read a CPU's performance feedback counters.
1188  * @cpunum: CPU from which to read counters.
1189  * @perf_fb_ctrs: ptr to cppc_perf_fb_ctrs. See cppc_acpi.h
1190  *
1191  * Return: 0 for success with perf_fb_ctrs populated else -ERRNO.
1192  */
1193 int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
1194 {
1195         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1196         struct cpc_register_resource *delivered_reg, *reference_reg,
1197                 *ref_perf_reg, *ctr_wrap_reg;
1198         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1199         struct cppc_pcc_data *pcc_ss_data = NULL;
1200         u64 delivered, reference, ref_perf, ctr_wrap_time;
1201         int ret = 0, regs_in_pcc = 0;
1202
1203         if (!cpc_desc) {
1204                 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1205                 return -ENODEV;
1206         }
1207
1208         delivered_reg = &cpc_desc->cpc_regs[DELIVERED_CTR];
1209         reference_reg = &cpc_desc->cpc_regs[REFERENCE_CTR];
1210         ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
1211         ctr_wrap_reg = &cpc_desc->cpc_regs[CTR_WRAP_TIME];
1212
1213         /*
1214          * If reference perf register is not supported then we should
1215          * use the nominal perf value
1216          */
1217         if (!CPC_SUPPORTED(ref_perf_reg))
1218                 ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
1219
1220         /* Are any of the regs PCC ?*/
1221         if (CPC_IN_PCC(delivered_reg) || CPC_IN_PCC(reference_reg) ||
1222                 CPC_IN_PCC(ctr_wrap_reg) || CPC_IN_PCC(ref_perf_reg)) {
1223                 if (pcc_ss_id < 0) {
1224                         pr_debug("Invalid pcc_ss_id\n");
1225                         return -ENODEV;
1226                 }
1227                 pcc_ss_data = pcc_data[pcc_ss_id];
1228                 down_write(&pcc_ss_data->pcc_lock);
1229                 regs_in_pcc = 1;
1230                 /* Ring doorbell once to update PCC subspace */
1231                 if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
1232                         ret = -EIO;
1233                         goto out_err;
1234                 }
1235         }
1236
1237         cpc_read(cpunum, delivered_reg, &delivered);
1238         cpc_read(cpunum, reference_reg, &reference);
1239         cpc_read(cpunum, ref_perf_reg, &ref_perf);
1240
1241         /*
1242          * Per spec, if ctr_wrap_time optional register is unsupported, then the
1243          * performance counters are assumed to never wrap during the lifetime of
1244          * platform
1245          */
1246         ctr_wrap_time = (u64)(~((u64)0));
1247         if (CPC_SUPPORTED(ctr_wrap_reg))
1248                 cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);
1249
1250         if (!delivered || !reference || !ref_perf) {
1251                 ret = -EFAULT;
1252                 goto out_err;
1253         }
1254
1255         perf_fb_ctrs->delivered = delivered;
1256         perf_fb_ctrs->reference = reference;
1257         perf_fb_ctrs->reference_perf = ref_perf;
1258         perf_fb_ctrs->wraparound_time = ctr_wrap_time;
1259 out_err:
1260         if (regs_in_pcc)
1261                 up_write(&pcc_ss_data->pcc_lock);
1262         return ret;
1263 }
1264 EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
1265
1266 /**
1267  * cppc_set_enable - Set to enable CPPC on the processor by writing the
1268  * Continuous Performance Control package EnableRegister field.
1269  * @cpu: CPU for which to enable CPPC register.
1270  * @enable: 0 - disable, 1 - enable CPPC feature on the processor.
1271  *
1272  * Return: 0 for success, -ERRNO or -EIO otherwise.
1273  */
1274 int cppc_set_enable(int cpu, bool enable)
1275 {
1276         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1277         struct cpc_register_resource *enable_reg;
1278         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1279         struct cppc_pcc_data *pcc_ss_data = NULL;
1280         int ret = -EINVAL;
1281
1282         if (!cpc_desc) {
1283                 pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1284                 return -EINVAL;
1285         }
1286
1287         enable_reg = &cpc_desc->cpc_regs[ENABLE];
1288
1289         if (CPC_IN_PCC(enable_reg)) {
1290
1291                 if (pcc_ss_id < 0)
1292                         return -EIO;
1293
1294                 ret = cpc_write(cpu, enable_reg, enable);
1295                 if (ret)
1296                         return ret;
1297
1298                 pcc_ss_data = pcc_data[pcc_ss_id];
1299
1300                 down_write(&pcc_ss_data->pcc_lock);
1301                 /* after writing CPC, transfer the ownership of PCC to platfrom */
1302                 ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
1303                 up_write(&pcc_ss_data->pcc_lock);
1304                 return ret;
1305         }
1306
1307         return cpc_write(cpu, enable_reg, enable);
1308 }
1309 EXPORT_SYMBOL_GPL(cppc_set_enable);
1310
1311 /**
1312  * cppc_set_perf - Set a CPU's performance controls.
1313  * @cpu: CPU for which to set performance controls.
1314  * @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
1315  *
1316  * Return: 0 for success, -ERRNO otherwise.
1317  */
1318 int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
1319 {
1320         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1321         struct cpc_register_resource *desired_reg;
1322         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1323         struct cppc_pcc_data *pcc_ss_data = NULL;
1324         int ret = 0;
1325
1326         if (!cpc_desc) {
1327                 pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1328                 return -ENODEV;
1329         }
1330
1331         desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
1332
1333         /*
1334          * This is Phase-I where we want to write to CPC registers
1335          * -> We want all CPUs to be able to execute this phase in parallel
1336          *
1337          * Since read_lock can be acquired by multiple CPUs simultaneously we
1338          * achieve that goal here
1339          */
1340         if (CPC_IN_PCC(desired_reg)) {
1341                 if (pcc_ss_id < 0) {
1342                         pr_debug("Invalid pcc_ss_id\n");
1343                         return -ENODEV;
1344                 }
1345                 pcc_ss_data = pcc_data[pcc_ss_id];
1346                 down_read(&pcc_ss_data->pcc_lock); /* BEGIN Phase-I */
1347                 if (pcc_ss_data->platform_owns_pcc) {
1348                         ret = check_pcc_chan(pcc_ss_id, false);
1349                         if (ret) {
1350                                 up_read(&pcc_ss_data->pcc_lock);
1351                                 return ret;
1352                         }
1353                 }
1354                 /*
1355                  * Update the pending_write to make sure a PCC CMD_READ will not
1356                  * arrive and steal the channel during the switch to write lock
1357                  */
1358                 pcc_ss_data->pending_pcc_write_cmd = true;
1359                 cpc_desc->write_cmd_id = pcc_ss_data->pcc_write_cnt;
1360                 cpc_desc->write_cmd_status = 0;
1361         }
1362
1363         /*
1364          * Skip writing MIN/MAX until Linux knows how to come up with
1365          * useful values.
1366          */
1367         cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);
1368
1369         if (CPC_IN_PCC(desired_reg))
1370                 up_read(&pcc_ss_data->pcc_lock);        /* END Phase-I */
1371         /*
1372          * This is Phase-II where we transfer the ownership of PCC to Platform
1373          *
1374          * Short Summary: Basically if we think of a group of cppc_set_perf
1375          * requests that happened in short overlapping interval. The last CPU to
1376          * come out of Phase-I will enter Phase-II and ring the doorbell.
1377          *
1378          * We have the following requirements for Phase-II:
1379          *     1. We want to execute Phase-II only when there are no CPUs
1380          * currently executing in Phase-I
1381          *     2. Once we start Phase-II we want to avoid all other CPUs from
1382          * entering Phase-I.
1383          *     3. We want only one CPU among all those who went through Phase-I
1384          * to run phase-II
1385          *
1386          * If write_trylock fails to get the lock and doesn't transfer the
1387          * PCC ownership to the platform, then one of the following will be TRUE
1388          *     1. There is at-least one CPU in Phase-I which will later execute
1389          * write_trylock, so the CPUs in Phase-I will be responsible for
1390          * executing the Phase-II.
1391          *     2. Some other CPU has beaten this CPU to successfully execute the
1392          * write_trylock and has already acquired the write_lock. We know for a
1393          * fact it (other CPU acquiring the write_lock) couldn't have happened
1394          * before this CPU's Phase-I as we held the read_lock.
1395          *     3. Some other CPU executing pcc CMD_READ has stolen the
1396          * down_write, in which case, send_pcc_cmd will check for pending
1397          * CMD_WRITE commands by checking the pending_pcc_write_cmd.
1398          * So this CPU can be certain that its request will be delivered
1399          *    So in all cases, this CPU knows that its request will be delivered
1400          * by another CPU and can return
1401          *
1402          * After getting the down_write we still need to check for
1403          * pending_pcc_write_cmd to take care of the following scenario
1404          *    The thread running this code could be scheduled out between
1405          * Phase-I and Phase-II. Before it is scheduled back on, another CPU
1406          * could have delivered the request to Platform by triggering the
1407          * doorbell and transferred the ownership of PCC to platform. So this
1408          * avoids triggering an unnecessary doorbell and more importantly before
1409          * triggering the doorbell it makes sure that the PCC channel ownership
1410          * is still with OSPM.
1411          *   pending_pcc_write_cmd can also be cleared by a different CPU, if
1412          * there was a pcc CMD_READ waiting on down_write and it steals the lock
1413          * before the pcc CMD_WRITE is completed. send_pcc_cmd checks for this
1414          * case during a CMD_READ and if there are pending writes it delivers
1415          * the write command before servicing the read command
1416          */
1417         if (CPC_IN_PCC(desired_reg)) {
1418                 if (down_write_trylock(&pcc_ss_data->pcc_lock)) {/* BEGIN Phase-II */
1419                         /* Update only if there are pending write commands */
1420                         if (pcc_ss_data->pending_pcc_write_cmd)
1421                                 send_pcc_cmd(pcc_ss_id, CMD_WRITE);
1422                         up_write(&pcc_ss_data->pcc_lock);       /* END Phase-II */
1423                 } else
1424                         /* Wait until pcc_write_cnt is updated by send_pcc_cmd */
1425                         wait_event(pcc_ss_data->pcc_write_wait_q,
1426                                    cpc_desc->write_cmd_id != pcc_ss_data->pcc_write_cnt);
1427
1428                 /* send_pcc_cmd updates the status in case of failure */
1429                 ret = cpc_desc->write_cmd_status;
1430         }
1431         return ret;
1432 }
1433 EXPORT_SYMBOL_GPL(cppc_set_perf);
1434
1435 /**
1436  * cppc_get_transition_latency - returns frequency transition latency in ns
1437  *
1438  * ACPI CPPC does not explicitly specify how a platform can specify the
1439  * transition latency for performance change requests. The closest we have
1440  * is the timing information from the PCCT tables which provides the info
1441  * on the number and frequency of PCC commands the platform can handle.
1442  */
1443 unsigned int cppc_get_transition_latency(int cpu_num)
1444 {
1445         /*
1446          * Expected transition latency is based on the PCCT timing values
1447          * Below are definition from ACPI spec:
1448          * pcc_nominal- Expected latency to process a command, in microseconds
1449          * pcc_mpar   - The maximum number of periodic requests that the subspace
1450          *              channel can support, reported in commands per minute. 0
1451          *              indicates no limitation.
1452          * pcc_mrtt   - The minimum amount of time that OSPM must wait after the
1453          *              completion of a command before issuing the next command,
1454          *              in microseconds.
1455          */
1456         unsigned int latency_ns = 0;
1457         struct cpc_desc *cpc_desc;
1458         struct cpc_register_resource *desired_reg;
1459         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu_num);
1460         struct cppc_pcc_data *pcc_ss_data;
1461
1462         cpc_desc = per_cpu(cpc_desc_ptr, cpu_num);
1463         if (!cpc_desc)
1464                 return CPUFREQ_ETERNAL;
1465
1466         desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
1467         if (!CPC_IN_PCC(desired_reg))
1468                 return CPUFREQ_ETERNAL;
1469
1470         if (pcc_ss_id < 0)
1471                 return CPUFREQ_ETERNAL;
1472
1473         pcc_ss_data = pcc_data[pcc_ss_id];
1474         if (pcc_ss_data->pcc_mpar)
1475                 latency_ns = 60 * (1000 * 1000 * 1000 / pcc_ss_data->pcc_mpar);
1476
1477         latency_ns = max(latency_ns, pcc_ss_data->pcc_nominal * 1000);
1478         latency_ns = max(latency_ns, pcc_ss_data->pcc_mrtt * 1000);
1479
1480         return latency_ns;
1481 }
1482 EXPORT_SYMBOL_GPL(cppc_get_transition_latency);