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 /* Check if a CPC register is in SystemMemory */
 104 #define CPC_IN_SYSTEM_MEMORY(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&   \
 105                                 (cpc)->cpc_entry.reg.space_id ==        \
 106                                 ACPI_ADR_SPACE_SYSTEM_MEMORY)
 107
 108 /* Check if a CPC register is in SystemIo */
 109 #define CPC_IN_SYSTEM_IO(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&       \
 110                                 (cpc)->cpc_entry.reg.space_id ==        \
 111                                 ACPI_ADR_SPACE_SYSTEM_IO)
 112
 113 /* Evaluates to True if reg is a NULL register descriptor */
 114 #define IS_NULL_REG(reg) ((reg)->space_id ==  ACPI_ADR_SPACE_SYSTEM_MEMORY && \
 115                                 (reg)->address == 0 &&                  \
 116                                 (reg)->bit_width == 0 &&                \
 117                                 (reg)->bit_offset == 0 &&               \
 118                                 (reg)->access_width == 0)
 119
 120 /* Evaluates to True if an optional cpc field is supported */
 121 #define CPC_SUPPORTED(cpc) ((cpc)->type == ACPI_TYPE_INTEGER ?          \
 122                                 !!(cpc)->cpc_entry.int_value :          \
 123                                 !IS_NULL_REG(&(cpc)->cpc_entry.reg))
 124 /*
 125  * Arbitrary Retries in case the remote processor is slow to respond
 126  * to PCC commands. Keeping it high enough to cover emulators where
 127  * the processors run painfully slow.
 128  */
 129 #define NUM_RETRIES 500ULL
 130
 131 #define OVER_16BTS_MASK ~0xFFFFULL
 132
 133 #define define_one_cppc_ro(_name)               \
 134 static struct kobj_attribute _name =            \
 135 __ATTR(_name, 0444, show_##_name, NULL)
 136
 137 #define to_cpc_desc(a) container_of(a, struct cpc_desc, kobj)
 138
 139 #define show_cppc_data(access_fn, struct_name, member_name)             \
 140         static ssize_t show_##member_name(struct kobject *kobj,         \
 141                                 struct kobj_attribute *attr, char *buf) \
 142         {                                                               \
 143                 struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);           \
 144                 struct struct_name st_name = {0};                       \
 145                 int ret;                                                \
 146                                                                         \
 147                 ret = access_fn(cpc_ptr->cpu_id, &st_name);             \
 148                 if (ret)                                                \
 149                         return ret;                                     \
 150                                                                         \
 151                 return scnprintf(buf, PAGE_SIZE, "%llu\n",              \
 152                                 (u64)st_name.member_name);              \
 153         }                                                               \
 154         define_one_cppc_ro(member_name)
 155
 156 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, highest_perf);
 157 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_perf);
 158 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_perf);
 159 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_nonlinear_perf);
 160 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_freq);
 161 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);
 162
 163 show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf);
 164 show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
 165
 166 static ssize_t show_feedback_ctrs(struct kobject *kobj,
 167                 struct kobj_attribute *attr, char *buf)
 168 {
 169         struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);
 170         struct cppc_perf_fb_ctrs fb_ctrs = {0};
 171         int ret;
 172
 173         ret = cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
 174         if (ret)
 175                 return ret;
 176
 177         return scnprintf(buf, PAGE_SIZE, "ref:%llu del:%llu\n",
 178                         fb_ctrs.reference, fb_ctrs.delivered);
 179 }
 180 define_one_cppc_ro(feedback_ctrs);
 181
 182 static struct attribute *cppc_attrs[] = {
 183         &feedback_ctrs.attr,
 184         &reference_perf.attr,
 185         &wraparound_time.attr,
 186         &highest_perf.attr,
 187         &lowest_perf.attr,
 188         &lowest_nonlinear_perf.attr,
 189         &nominal_perf.attr,
 190         &nominal_freq.attr,
 191         &lowest_freq.attr,
 192         NULL
 193 };
 194 ATTRIBUTE_GROUPS(cppc);
 195
 196 static struct kobj_type cppc_ktype = {
 197         .sysfs_ops = &kobj_sysfs_ops,
 198         .default_groups = cppc_groups,
 199 };
 200
 201 static int check_pcc_chan(int pcc_ss_id, bool chk_err_bit)
 202 {
 203         int ret, status;
 204         struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
 205         struct acpi_pcct_shared_memory __iomem *generic_comm_base =
 206                 pcc_ss_data->pcc_comm_addr;
 207
 208         if (!pcc_ss_data->platform_owns_pcc)
 209                 return 0;
 210
 211         /*
 212          * Poll PCC status register every 3us(delay_us) for maximum of
 213          * deadline_us(timeout_us) until PCC command complete bit is set(cond)
 214          */
 215         ret = readw_relaxed_poll_timeout(&generic_comm_base->status, status,
 216                                         status & PCC_CMD_COMPLETE_MASK, 3,
 217                                         pcc_ss_data->deadline_us);
 218
 219         if (likely(!ret)) {
 220                 pcc_ss_data->platform_owns_pcc = false;
 221                 if (chk_err_bit && (status & PCC_ERROR_MASK))
 222                         ret = -EIO;
 223         }
 224
 225         if (unlikely(ret))
 226                 pr_err("PCC check channel failed for ss: %d. ret=%d\n",
 227                        pcc_ss_id, ret);
 228
 229         return ret;
 230 }
 231
 232 /*
 233  * This function transfers the ownership of the PCC to the platform
 234  * So it must be called while holding write_lock(pcc_lock)
 235  */
 236 static int send_pcc_cmd(int pcc_ss_id, u16 cmd)
 237 {
 238         int ret = -EIO, i;
 239         struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
 240         struct acpi_pcct_shared_memory __iomem *generic_comm_base =
 241                 pcc_ss_data->pcc_comm_addr;
 242         unsigned int time_delta;
 243
 244         /*
 245          * For CMD_WRITE we know for a fact the caller should have checked
 246          * the channel before writing to PCC space
 247          */
 248         if (cmd == CMD_READ) {
 249                 /*
 250                  * If there are pending cpc_writes, then we stole the channel
 251                  * before write completion, so first send a WRITE command to
 252                  * platform
 253                  */
 254                 if (pcc_ss_data->pending_pcc_write_cmd)
 255                         send_pcc_cmd(pcc_ss_id, CMD_WRITE);
 256
 257                 ret = check_pcc_chan(pcc_ss_id, false);
 258                 if (ret)
 259                         goto end;
 260         } else /* CMD_WRITE */
 261                 pcc_ss_data->pending_pcc_write_cmd = FALSE;
 262
 263         /*
 264          * Handle the Minimum Request Turnaround Time(MRTT)
 265          * "The minimum amount of time that OSPM must wait after the completion
 266          * of a command before issuing the next command, in microseconds"
 267          */
 268         if (pcc_ss_data->pcc_mrtt) {
 269                 time_delta = ktime_us_delta(ktime_get(),
 270                                             pcc_ss_data->last_cmd_cmpl_time);
 271                 if (pcc_ss_data->pcc_mrtt > time_delta)
 272                         udelay(pcc_ss_data->pcc_mrtt - time_delta);
 273         }
 274
 275         /*
 276          * Handle the non-zero Maximum Periodic Access Rate(MPAR)
 277          * "The maximum number of periodic requests that the subspace channel can
 278          * support, reported in commands per minute. 0 indicates no limitation."
 279          *
 280          * This parameter should be ideally zero or large enough so that it can
 281          * handle maximum number of requests that all the cores in the system can
 282          * collectively generate. If it is not, we will follow the spec and just
 283          * not send the request to the platform after hitting the MPAR limit in
 284          * any 60s window
 285          */
 286         if (pcc_ss_data->pcc_mpar) {
 287                 if (pcc_ss_data->mpar_count == 0) {
 288                         time_delta = ktime_ms_delta(ktime_get(),
 289                                                     pcc_ss_data->last_mpar_reset);
 290                         if ((time_delta < 60 * MSEC_PER_SEC) && pcc_ss_data->last_mpar_reset) {
 291                                 pr_debug("PCC cmd for subspace %d not sent due to MPAR limit",
 292                                          pcc_ss_id);
 293                                 ret = -EIO;
 294                                 goto end;
 295                         }
 296                         pcc_ss_data->last_mpar_reset = ktime_get();
 297                         pcc_ss_data->mpar_count = pcc_ss_data->pcc_mpar;
 298                 }
 299                 pcc_ss_data->mpar_count--;
 300         }
 301
 302         /* Write to the shared comm region. */
 303         writew_relaxed(cmd, &generic_comm_base->command);
 304
 305         /* Flip CMD COMPLETE bit */
 306         writew_relaxed(0, &generic_comm_base->status);
 307
 308         pcc_ss_data->platform_owns_pcc = true;
 309
 310         /* Ring doorbell */
 311         ret = mbox_send_message(pcc_ss_data->pcc_channel->mchan, &cmd);
 312         if (ret < 0) {
 313                 pr_err("Err sending PCC mbox message. ss: %d cmd:%d, ret:%d\n",
 314                        pcc_ss_id, cmd, ret);
 315                 goto end;
 316         }
 317
 318         /* wait for completion and check for PCC error bit */
 319         ret = check_pcc_chan(pcc_ss_id, true);
 320
 321         if (pcc_ss_data->pcc_mrtt)
 322                 pcc_ss_data->last_cmd_cmpl_time = ktime_get();
 323
 324         if (pcc_ss_data->pcc_channel->mchan->mbox->txdone_irq)
 325                 mbox_chan_txdone(pcc_ss_data->pcc_channel->mchan, ret);
 326         else
 327                 mbox_client_txdone(pcc_ss_data->pcc_channel->mchan, ret);
 328
 329 end:
 330         if (cmd == CMD_WRITE) {
 331                 if (unlikely(ret)) {
 332                         for_each_possible_cpu(i) {
 333                                 struct cpc_desc *desc = per_cpu(cpc_desc_ptr, i);
 334
 335                                 if (!desc)
 336                                         continue;
 337
 338                                 if (desc->write_cmd_id == pcc_ss_data->pcc_write_cnt)
 339                                         desc->write_cmd_status = ret;
 340                         }
 341                 }
 342                 pcc_ss_data->pcc_write_cnt++;
 343                 wake_up_all(&pcc_ss_data->pcc_write_wait_q);
 344         }
 345
 346         return ret;
 347 }
 348
 349 static void cppc_chan_tx_done(struct mbox_client *cl, void *msg, int ret)
 350 {
 351         if (ret < 0)
 352                 pr_debug("TX did not complete: CMD sent:%x, ret:%d\n",
 353                                 *(u16 *)msg, ret);
 354         else
 355                 pr_debug("TX completed. CMD sent:%x, ret:%d\n",
 356                                 *(u16 *)msg, ret);
 357 }
 358
 359 static struct mbox_client cppc_mbox_cl = {
 360         .tx_done = cppc_chan_tx_done,
 361         .knows_txdone = true,
 362 };
 363
 364 static int acpi_get_psd(struct cpc_desc *cpc_ptr, acpi_handle handle)
 365 {
 366         int result = -EFAULT;
 367         acpi_status status = AE_OK;
 368         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 369         struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
 370         struct acpi_buffer state = {0, NULL};
 371         union acpi_object  *psd = NULL;
 372         struct acpi_psd_package *pdomain;
 373
 374         status = acpi_evaluate_object_typed(handle, "_PSD", NULL,
 375                                             &buffer, ACPI_TYPE_PACKAGE);
 376         if (status == AE_NOT_FOUND)     /* _PSD is optional */
 377                 return 0;
 378         if (ACPI_FAILURE(status))
 379                 return -ENODEV;
 380
 381         psd = buffer.pointer;
 382         if (!psd || psd->package.count != 1) {
 383                 pr_debug("Invalid _PSD data\n");
 384                 goto end;
 385         }
 386
 387         pdomain = &(cpc_ptr->domain_info);
 388
 389         state.length = sizeof(struct acpi_psd_package);
 390         state.pointer = pdomain;
 391
 392         status = acpi_extract_package(&(psd->package.elements[0]),
 393                 &format, &state);
 394         if (ACPI_FAILURE(status)) {
 395                 pr_debug("Invalid _PSD data for CPU:%d\n", cpc_ptr->cpu_id);
 396                 goto end;
 397         }
 398
 399         if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
 400                 pr_debug("Unknown _PSD:num_entries for CPU:%d\n", cpc_ptr->cpu_id);
 401                 goto end;
 402         }
 403
 404         if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
 405                 pr_debug("Unknown _PSD:revision for CPU: %d\n", cpc_ptr->cpu_id);
 406                 goto end;
 407         }
 408
 409         if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
 410             pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
 411             pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
 412                 pr_debug("Invalid _PSD:coord_type for CPU:%d\n", cpc_ptr->cpu_id);
 413                 goto end;
 414         }
 415
 416         result = 0;
 417 end:
 418         kfree(buffer.pointer);
 419         return result;
 420 }
 421
 422 bool acpi_cpc_valid(void)
 423 {
 424         struct cpc_desc *cpc_ptr;
 425         int cpu;
 426
 427         for_each_present_cpu(cpu) {
 428                 cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 429                 if (!cpc_ptr)
 430                         return false;
 431         }
 432
 433         return true;
 434 }
 435 EXPORT_SYMBOL_GPL(acpi_cpc_valid);
 436
 437 bool cppc_allow_fast_switch(void)
 438 {
 439         struct cpc_register_resource *desired_reg;
 440         struct cpc_desc *cpc_ptr;
 441         int cpu;
 442
 443         for_each_possible_cpu(cpu) {
 444                 cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 445                 desired_reg = &cpc_ptr->cpc_regs[DESIRED_PERF];
 446                 if (!CPC_IN_SYSTEM_MEMORY(desired_reg) &&
 447                                 !CPC_IN_SYSTEM_IO(desired_reg))
 448                         return false;
 449         }
 450
 451         return true;
 452 }
 453 EXPORT_SYMBOL_GPL(cppc_allow_fast_switch);
 454
 455 /**
 456  * acpi_get_psd_map - Map the CPUs in the freq domain of a given cpu
 457  * @cpu: Find all CPUs that share a domain with cpu.
 458  * @cpu_data: Pointer to CPU specific CPPC data including PSD info.
 459  *
 460  *      Return: 0 for success or negative value for err.
 461  */
 462 int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data)
 463 {
 464         struct cpc_desc *cpc_ptr, *match_cpc_ptr;
 465         struct acpi_psd_package *match_pdomain;
 466         struct acpi_psd_package *pdomain;
 467         int count_target, i;
 468
 469         /*
 470          * Now that we have _PSD data from all CPUs, let's setup P-state
 471          * domain info.
 472          */
 473         cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 474         if (!cpc_ptr)
 475                 return -EFAULT;
 476
 477         pdomain = &(cpc_ptr->domain_info);
 478         cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
 479         if (pdomain->num_processors <= 1)
 480                 return 0;
 481
 482         /* Validate the Domain info */
 483         count_target = pdomain->num_processors;
 484         if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
 485                 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 486         else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
 487                 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_HW;
 488         else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
 489                 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 490
 491         for_each_possible_cpu(i) {
 492                 if (i == cpu)
 493                         continue;
 494
 495                 match_cpc_ptr = per_cpu(cpc_desc_ptr, i);
 496                 if (!match_cpc_ptr)
 497                         goto err_fault;
 498
 499                 match_pdomain = &(match_cpc_ptr->domain_info);
 500                 if (match_pdomain->domain != pdomain->domain)
 501                         continue;
 502
 503                 /* Here i and cpu are in the same domain */
 504                 if (match_pdomain->num_processors != count_target)
 505                         goto err_fault;
 506
 507                 if (pdomain->coord_type != match_pdomain->coord_type)
 508                         goto err_fault;
 509
 510                 cpumask_set_cpu(i, cpu_data->shared_cpu_map);
 511         }
 512
 513         return 0;
 514
 515 err_fault:
 516         /* Assume no coordination on any error parsing domain info */
 517         cpumask_clear(cpu_data->shared_cpu_map);
 518         cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
 519         cpu_data->shared_type = CPUFREQ_SHARED_TYPE_NONE;
 520
 521         return -EFAULT;
 522 }
 523 EXPORT_SYMBOL_GPL(acpi_get_psd_map);
 524
 525 static int register_pcc_channel(int pcc_ss_idx)
 526 {
 527         struct pcc_mbox_chan *pcc_chan;
 528         u64 usecs_lat;
 529
 530         if (pcc_ss_idx >= 0) {
 531                 pcc_chan = pcc_mbox_request_channel(&cppc_mbox_cl, pcc_ss_idx);
 532
 533                 if (IS_ERR(pcc_chan)) {
 534                         pr_err("Failed to find PCC channel for subspace %d\n",
 535                                pcc_ss_idx);
 536                         return -ENODEV;
 537                 }
 538
 539                 pcc_data[pcc_ss_idx]->pcc_channel = pcc_chan;
 540                 /*
 541                  * cppc_ss->latency is just a Nominal value. In reality
 542                  * the remote processor could be much slower to reply.
 543                  * So add an arbitrary amount of wait on top of Nominal.
 544                  */
 545                 usecs_lat = NUM_RETRIES * pcc_chan->latency;
 546                 pcc_data[pcc_ss_idx]->deadline_us = usecs_lat;
 547                 pcc_data[pcc_ss_idx]->pcc_mrtt = pcc_chan->min_turnaround_time;
 548                 pcc_data[pcc_ss_idx]->pcc_mpar = pcc_chan->max_access_rate;
 549                 pcc_data[pcc_ss_idx]->pcc_nominal = pcc_chan->latency;
 550
 551                 pcc_data[pcc_ss_idx]->pcc_comm_addr =
 552                         acpi_os_ioremap(pcc_chan->shmem_base_addr,
 553                                         pcc_chan->shmem_size);
 554                 if (!pcc_data[pcc_ss_idx]->pcc_comm_addr) {
 555                         pr_err("Failed to ioremap PCC comm region mem for %d\n",
 556                                pcc_ss_idx);
 557                         return -ENOMEM;
 558                 }
 559
 560                 /* Set flag so that we don't come here for each CPU. */
 561                 pcc_data[pcc_ss_idx]->pcc_channel_acquired = true;
 562         }
 563
 564         return 0;
 565 }
 566
 567 /**
 568  * cpc_ffh_supported() - check if FFH reading supported
 569  *
 570  * Check if the architecture has support for functional fixed hardware
 571  * read/write capability.
 572  *
 573  * Return: true for supported, false for not supported
 574  */
 575 bool __weak cpc_ffh_supported(void)
 576 {
 577         return false;
 578 }
 579
 580 /**
 581  * cpc_supported_by_cpu() - check if CPPC is supported by CPU
 582  *
 583  * Check if the architectural support for CPPC is present even
 584  * if the _OSC hasn't prescribed it
 585  *
 586  * Return: true for supported, false for not supported
 587  */
 588 bool __weak cpc_supported_by_cpu(void)
 589 {
 590         return false;
 591 }
 592
 593 /**
 594  * pcc_data_alloc() - Allocate the pcc_data memory for pcc subspace
 595  *
 596  * Check and allocate the cppc_pcc_data memory.
 597  * In some processor configurations it is possible that same subspace
 598  * is shared between multiple CPUs. This is seen especially in CPUs
 599  * with hardware multi-threading support.
 600  *
 601  * Return: 0 for success, errno for failure
 602  */
 603 static int pcc_data_alloc(int pcc_ss_id)
 604 {
 605         if (pcc_ss_id < 0 || pcc_ss_id >= MAX_PCC_SUBSPACES)
 606                 return -EINVAL;
 607
 608         if (pcc_data[pcc_ss_id]) {
 609                 pcc_data[pcc_ss_id]->refcount++;
 610         } else {
 611                 pcc_data[pcc_ss_id] = kzalloc(sizeof(struct cppc_pcc_data),
 612                                               GFP_KERNEL);
 613                 if (!pcc_data[pcc_ss_id])
 614                         return -ENOMEM;
 615                 pcc_data[pcc_ss_id]->refcount++;
 616         }
 617
 618         return 0;
 619 }
 620
 621 /* Check if CPPC revision + num_ent combination is supported */
 622 static bool is_cppc_supported(int revision, int num_ent)
 623 {
 624         int expected_num_ent;
 625
 626         switch (revision) {
 627         case CPPC_V2_REV:
 628                 expected_num_ent = CPPC_V2_NUM_ENT;
 629                 break;
 630         case CPPC_V3_REV:
 631                 expected_num_ent = CPPC_V3_NUM_ENT;
 632                 break;
 633         default:
 634                 pr_debug("Firmware exports unsupported CPPC revision: %d\n",
 635                         revision);
 636                 return false;
 637         }
 638
 639         if (expected_num_ent != num_ent) {
 640                 pr_debug("Firmware exports %d entries. Expected: %d for CPPC rev:%d\n",
 641                         num_ent, expected_num_ent, revision);
 642                 return false;
 643         }
 644
 645         return true;
 646 }
 647
 648 /*
 649  * An example CPC table looks like the following.
 650  *
 651  *  Name (_CPC, Package() {
 652  *      17,                                                     // NumEntries
 653  *      1,                                                      // Revision
 654  *      ResourceTemplate() {Register(PCC, 32, 0, 0x120, 2)},    // Highest Performance
 655  *      ResourceTemplate() {Register(PCC, 32, 0, 0x124, 2)},    // Nominal Performance
 656  *      ResourceTemplate() {Register(PCC, 32, 0, 0x128, 2)},    // Lowest Nonlinear Performance
 657  *      ResourceTemplate() {Register(PCC, 32, 0, 0x12C, 2)},    // Lowest Performance
 658  *      ResourceTemplate() {Register(PCC, 32, 0, 0x130, 2)},    // Guaranteed Performance Register
 659  *      ResourceTemplate() {Register(PCC, 32, 0, 0x110, 2)},    // Desired Performance Register
 660  *      ResourceTemplate() {Register(SystemMemory, 0, 0, 0, 0)},
 661  *      ...
 662  *      ...
 663  *      ...
 664  *  }
 665  * Each Register() encodes how to access that specific register.
 666  * e.g. a sample PCC entry has the following encoding:
 667  *
 668  *  Register (
 669  *      PCC,    // AddressSpaceKeyword
 670  *      8,      // RegisterBitWidth
 671  *      8,      // RegisterBitOffset
 672  *      0x30,   // RegisterAddress
 673  *      9,      // AccessSize (subspace ID)
 674  *  )
 675  */
 676
 677 #ifndef arch_init_invariance_cppc
 678 static inline void arch_init_invariance_cppc(void) { }
 679 #endif
 680
 681 /**
 682  * acpi_cppc_processor_probe - Search for per CPU _CPC objects.
 683  * @pr: Ptr to acpi_processor containing this CPU's logical ID.
 684  *
 685  *      Return: 0 for success or negative value for err.
 686  */
 687 int acpi_cppc_processor_probe(struct acpi_processor *pr)
 688 {
 689         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 690         union acpi_object *out_obj, *cpc_obj;
 691         struct cpc_desc *cpc_ptr;
 692         struct cpc_reg *gas_t;
 693         struct device *cpu_dev;
 694         acpi_handle handle = pr->handle;
 695         unsigned int num_ent, i, cpc_rev;
 696         int pcc_subspace_id = -1;
 697         acpi_status status;
 698         int ret = -ENODATA;
 699
 700         if (!osc_sb_cppc2_support_acked) {
 701                 pr_debug("CPPC v2 _OSC not acked\n");
 702                 if (!cpc_supported_by_cpu())
 703                         return -ENODEV;
 704         }
 705
 706         /* Parse the ACPI _CPC table for this CPU. */
 707         status = acpi_evaluate_object_typed(handle, "_CPC", NULL, &output,
 708                         ACPI_TYPE_PACKAGE);
 709         if (ACPI_FAILURE(status)) {
 710                 ret = -ENODEV;
 711                 goto out_buf_free;
 712         }
 713
 714         out_obj = (union acpi_object *) output.pointer;
 715
 716         cpc_ptr = kzalloc(sizeof(struct cpc_desc), GFP_KERNEL);
 717         if (!cpc_ptr) {
 718                 ret = -ENOMEM;
 719                 goto out_buf_free;
 720         }
 721
 722         /* First entry is NumEntries. */
 723         cpc_obj = &out_obj->package.elements[0];
 724         if (cpc_obj->type == ACPI_TYPE_INTEGER) {
 725                 num_ent = cpc_obj->integer.value;
 726                 if (num_ent <= 1) {
 727                         pr_debug("Unexpected _CPC NumEntries value (%d) for CPU:%d\n",
 728                                  num_ent, pr->id);
 729                         goto out_free;
 730                 }
 731         } else {
 732                 pr_debug("Unexpected _CPC NumEntries entry type (%d) for CPU:%d\n",
 733                          cpc_obj->type, pr->id);
 734                 goto out_free;
 735         }
 736         cpc_ptr->num_entries = num_ent;
 737
 738         /* Second entry should be revision. */
 739         cpc_obj = &out_obj->package.elements[1];
 740         if (cpc_obj->type == ACPI_TYPE_INTEGER) {
 741                 cpc_rev = cpc_obj->integer.value;
 742         } else {
 743                 pr_debug("Unexpected _CPC Revision entry type (%d) for CPU:%d\n",
 744                          cpc_obj->type, pr->id);
 745                 goto out_free;
 746         }
 747         cpc_ptr->version = cpc_rev;
 748
 749         if (!is_cppc_supported(cpc_rev, num_ent))
 750                 goto out_free;
 751
 752         /* Iterate through remaining entries in _CPC */
 753         for (i = 2; i < num_ent; i++) {
 754                 cpc_obj = &out_obj->package.elements[i];
 755
 756                 if (cpc_obj->type == ACPI_TYPE_INTEGER) {
 757                         cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_INTEGER;
 758                         cpc_ptr->cpc_regs[i-2].cpc_entry.int_value = cpc_obj->integer.value;
 759                 } else if (cpc_obj->type == ACPI_TYPE_BUFFER) {
 760                         gas_t = (struct cpc_reg *)
 761                                 cpc_obj->buffer.pointer;
 762
 763                         /*
 764                          * The PCC Subspace index is encoded inside
 765                          * the CPC table entries. The same PCC index
 766                          * will be used for all the PCC entries,
 767                          * so extract it only once.
 768                          */
 769                         if (gas_t->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
 770                                 if (pcc_subspace_id < 0) {
 771                                         pcc_subspace_id = gas_t->access_width;
 772                                         if (pcc_data_alloc(pcc_subspace_id))
 773                                                 goto out_free;
 774                                 } else if (pcc_subspace_id != gas_t->access_width) {
 775                                         pr_debug("Mismatched PCC ids in _CPC for CPU:%d\n",
 776                                                  pr->id);
 777                                         goto out_free;
 778                                 }
 779                         } else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 780                                 if (gas_t->address) {
 781                                         void __iomem *addr;
 782
 783                                         if (!osc_cpc_flexible_adr_space_confirmed) {
 784                                                 pr_debug("Flexible address space capability not supported\n");
 785                                                 if (!cpc_supported_by_cpu())
 786                                                         goto out_free;
 787                                         }
 788
 789                                         addr = ioremap(gas_t->address, gas_t->bit_width/8);
 790                                         if (!addr)
 791                                                 goto out_free;
 792                                         cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
 793                                 }
 794                         } else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
 795                                 if (gas_t->access_width < 1 || gas_t->access_width > 3) {
 796                                         /*
 797                                          * 1 = 8-bit, 2 = 16-bit, and 3 = 32-bit.
 798                                          * SystemIO doesn't implement 64-bit
 799                                          * registers.
 800                                          */
 801                                         pr_debug("Invalid access width %d for SystemIO register in _CPC\n",
 802                                                  gas_t->access_width);
 803                                         goto out_free;
 804                                 }
 805                                 if (gas_t->address & OVER_16BTS_MASK) {
 806                                         /* SystemIO registers use 16-bit integer addresses */
 807                                         pr_debug("Invalid IO port %llu for SystemIO register in _CPC\n",
 808                                                  gas_t->address);
 809                                         goto out_free;
 810                                 }
 811                                 if (!osc_cpc_flexible_adr_space_confirmed) {
 812                                         pr_debug("Flexible address space capability not supported\n");
 813                                         if (!cpc_supported_by_cpu())
 814                                                 goto out_free;
 815                                 }
 816                         } else {
 817                                 if (gas_t->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE || !cpc_ffh_supported()) {
 818                                         /* Support only PCC, SystemMemory, SystemIO, and FFH type regs. */
 819                                         pr_debug("Unsupported register type (%d) in _CPC\n",
 820                                                  gas_t->space_id);
 821                                         goto out_free;
 822                                 }
 823                         }
 824
 825                         cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_BUFFER;
 826                         memcpy(&cpc_ptr->cpc_regs[i-2].cpc_entry.reg, gas_t, sizeof(*gas_t));
 827                 } else {
 828                         pr_debug("Invalid entry type (%d) in _CPC for CPU:%d\n",
 829                                  i, pr->id);
 830                         goto out_free;
 831                 }
 832         }
 833         per_cpu(cpu_pcc_subspace_idx, pr->id) = pcc_subspace_id;
 834
 835         /*
 836          * Initialize the remaining cpc_regs as unsupported.
 837          * Example: In case FW exposes CPPC v2, the below loop will initialize
 838          * LOWEST_FREQ and NOMINAL_FREQ regs as unsupported
 839          */
 840         for (i = num_ent - 2; i < MAX_CPC_REG_ENT; i++) {
 841                 cpc_ptr->cpc_regs[i].type = ACPI_TYPE_INTEGER;
 842                 cpc_ptr->cpc_regs[i].cpc_entry.int_value = 0;
 843         }
 844
 845
 846         /* Store CPU Logical ID */
 847         cpc_ptr->cpu_id = pr->id;
 848
 849         /* Parse PSD data for this CPU */
 850         ret = acpi_get_psd(cpc_ptr, handle);
 851         if (ret)
 852                 goto out_free;
 853
 854         /* Register PCC channel once for all PCC subspace ID. */
 855         if (pcc_subspace_id >= 0 && !pcc_data[pcc_subspace_id]->pcc_channel_acquired) {
 856                 ret = register_pcc_channel(pcc_subspace_id);
 857                 if (ret)
 858                         goto out_free;
 859
 860                 init_rwsem(&pcc_data[pcc_subspace_id]->pcc_lock);
 861                 init_waitqueue_head(&pcc_data[pcc_subspace_id]->pcc_write_wait_q);
 862         }
 863
 864         /* Everything looks okay */
 865         pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);
 866
 867         /* Add per logical CPU nodes for reading its feedback counters. */
 868         cpu_dev = get_cpu_device(pr->id);
 869         if (!cpu_dev) {
 870                 ret = -EINVAL;
 871                 goto out_free;
 872         }
 873
 874         /* Plug PSD data into this CPU's CPC descriptor. */
 875         per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
 876
 877         ret = kobject_init_and_add(&cpc_ptr->kobj, &cppc_ktype, &cpu_dev->kobj,
 878                         "acpi_cppc");
 879         if (ret) {
 880                 per_cpu(cpc_desc_ptr, pr->id) = NULL;
 881                 kobject_put(&cpc_ptr->kobj);
 882                 goto out_free;
 883         }
 884
 885         arch_init_invariance_cppc();
 886
 887         kfree(output.pointer);
 888         return 0;
 889
 890 out_free:
 891         /* Free all the mapped sys mem areas for this CPU */
 892         for (i = 2; i < cpc_ptr->num_entries; i++) {
 893                 void __iomem *addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
 894
 895                 if (addr)
 896                         iounmap(addr);
 897         }
 898         kfree(cpc_ptr);
 899
 900 out_buf_free:
 901         kfree(output.pointer);
 902         return ret;
 903 }
 904 EXPORT_SYMBOL_GPL(acpi_cppc_processor_probe);
 905
 906 /**
 907  * acpi_cppc_processor_exit - Cleanup CPC structs.
 908  * @pr: Ptr to acpi_processor containing this CPU's logical ID.
 909  *
 910  * Return: Void
 911  */
 912 void acpi_cppc_processor_exit(struct acpi_processor *pr)
 913 {
 914         struct cpc_desc *cpc_ptr;
 915         unsigned int i;
 916         void __iomem *addr;
 917         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, pr->id);
 918
 919         if (pcc_ss_id >= 0 && pcc_data[pcc_ss_id]) {
 920                 if (pcc_data[pcc_ss_id]->pcc_channel_acquired) {
 921                         pcc_data[pcc_ss_id]->refcount--;
 922                         if (!pcc_data[pcc_ss_id]->refcount) {
 923                                 pcc_mbox_free_channel(pcc_data[pcc_ss_id]->pcc_channel);
 924                                 kfree(pcc_data[pcc_ss_id]);
 925                                 pcc_data[pcc_ss_id] = NULL;
 926                         }
 927                 }
 928         }
 929
 930         cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
 931         if (!cpc_ptr)
 932                 return;
 933
 934         /* Free all the mapped sys mem areas for this CPU */
 935         for (i = 2; i < cpc_ptr->num_entries; i++) {
 936                 addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
 937                 if (addr)
 938                         iounmap(addr);
 939         }
 940
 941         kobject_put(&cpc_ptr->kobj);
 942         kfree(cpc_ptr);
 943 }
 944 EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
 945
 946 /**
 947  * cpc_read_ffh() - Read FFH register
 948  * @cpunum:     CPU number to read
 949  * @reg:        cppc register information
 950  * @val:        place holder for return value
 951  *
 952  * Read bit_width bits from a specified address and bit_offset
 953  *
 954  * Return: 0 for success and error code
 955  */
 956 int __weak cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
 957 {
 958         return -ENOTSUPP;
 959 }
 960
 961 /**
 962  * cpc_write_ffh() - Write FFH register
 963  * @cpunum:     CPU number to write
 964  * @reg:        cppc register information
 965  * @val:        value to write
 966  *
 967  * Write value of bit_width bits to a specified address and bit_offset
 968  *
 969  * Return: 0 for success and error code
 970  */
 971 int __weak cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
 972 {
 973         return -ENOTSUPP;
 974 }
 975
 976 /*
 977  * Since cpc_read and cpc_write are called while holding pcc_lock, it should be
 978  * as fast as possible. We have already mapped the PCC subspace during init, so
 979  * we can directly write to it.
 980  */
 981
 982 static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 983 {
 984         void __iomem *vaddr = NULL;
 985         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
 986         struct cpc_reg *reg = &reg_res->cpc_entry.reg;
 987
 988         if (reg_res->type == ACPI_TYPE_INTEGER) {
 989                 *val = reg_res->cpc_entry.int_value;
 990                 return 0;
 991         }
 992
 993         *val = 0;
 994
 995         if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
 996                 u32 width = 8 << (reg->access_width - 1);
 997                 u32 val_u32;
 998                 acpi_status status;
 999
1000                 status = acpi_os_read_port((acpi_io_address)reg->address,
1001                                            &val_u32, width);
1002                 if (ACPI_FAILURE(status)) {
1003                         pr_debug("Error: Failed to read SystemIO port %llx\n",
1004                                  reg->address);
1005                         return -EFAULT;
1006                 }
1007
1008                 *val = val_u32;
1009                 return 0;
1010         } else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
1011                 vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
1012         else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
1013                 vaddr = reg_res->sys_mem_vaddr;
1014         else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
1015                 return cpc_read_ffh(cpu, reg, val);
1016         else
1017                 return acpi_os_read_memory((acpi_physical_address)reg->address,
1018                                 val, reg->bit_width);
1019
1020         switch (reg->bit_width) {
1021         case 8:
1022                 *val = readb_relaxed(vaddr);
1023                 break;
1024         case 16:
1025                 *val = readw_relaxed(vaddr);
1026                 break;
1027         case 32:
1028                 *val = readl_relaxed(vaddr);
1029                 break;
1030         case 64:
1031                 *val = readq_relaxed(vaddr);
1032                 break;
1033         default:
1034                 pr_debug("Error: Cannot read %u bit width from PCC for ss: %d\n",
1035                          reg->bit_width, pcc_ss_id);
1036                 return -EFAULT;
1037         }
1038
1039         return 0;
1040 }
1041
1042 static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
1043 {
1044         int ret_val = 0;
1045         void __iomem *vaddr = NULL;
1046         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1047         struct cpc_reg *reg = &reg_res->cpc_entry.reg;
1048
1049         if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
1050                 u32 width = 8 << (reg->access_width - 1);
1051                 acpi_status status;
1052
1053                 status = acpi_os_write_port((acpi_io_address)reg->address,
1054                                             (u32)val, width);
1055                 if (ACPI_FAILURE(status)) {
1056                         pr_debug("Error: Failed to write SystemIO port %llx\n",
1057                                  reg->address);
1058                         return -EFAULT;
1059                 }
1060
1061                 return 0;
1062         } else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
1063                 vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
1064         else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
1065                 vaddr = reg_res->sys_mem_vaddr;
1066         else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
1067                 return cpc_write_ffh(cpu, reg, val);
1068         else
1069                 return acpi_os_write_memory((acpi_physical_address)reg->address,
1070                                 val, reg->bit_width);
1071
1072         switch (reg->bit_width) {
1073         case 8:
1074                 writeb_relaxed(val, vaddr);
1075                 break;
1076         case 16:
1077                 writew_relaxed(val, vaddr);
1078                 break;
1079         case 32:
1080                 writel_relaxed(val, vaddr);
1081                 break;
1082         case 64:
1083                 writeq_relaxed(val, vaddr);
1084                 break;
1085         default:
1086                 pr_debug("Error: Cannot write %u bit width to PCC for ss: %d\n",
1087                          reg->bit_width, pcc_ss_id);
1088                 ret_val = -EFAULT;
1089                 break;
1090         }
1091
1092         return ret_val;
1093 }
1094
1095 static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
1096 {
1097         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1098         struct cpc_register_resource *reg;
1099
1100         if (!cpc_desc) {
1101                 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1102                 return -ENODEV;
1103         }
1104
1105         reg = &cpc_desc->cpc_regs[reg_idx];
1106
1107         if (CPC_IN_PCC(reg)) {
1108                 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1109                 struct cppc_pcc_data *pcc_ss_data = NULL;
1110                 int ret = 0;
1111
1112                 if (pcc_ss_id < 0)
1113                         return -EIO;
1114
1115                 pcc_ss_data = pcc_data[pcc_ss_id];
1116
1117                 down_write(&pcc_ss_data->pcc_lock);
1118
1119                 if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0)
1120                         cpc_read(cpunum, reg, perf);
1121                 else
1122                         ret = -EIO;
1123
1124                 up_write(&pcc_ss_data->pcc_lock);
1125
1126                 return ret;
1127         }
1128
1129         cpc_read(cpunum, reg, perf);
1130
1131         return 0;
1132 }
1133
1134 /**
1135  * cppc_get_desired_perf - Get the desired performance register value.
1136  * @cpunum: CPU from which to get desired performance.
1137  * @desired_perf: Return address.
1138  *
1139  * Return: 0 for success, -EIO otherwise.
1140  */
1141 int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
1142 {
1143         return cppc_get_perf(cpunum, DESIRED_PERF, desired_perf);
1144 }
1145 EXPORT_SYMBOL_GPL(cppc_get_desired_perf);
1146
1147 /**
1148  * cppc_get_nominal_perf - Get the nominal performance register value.
1149  * @cpunum: CPU from which to get nominal performance.
1150  * @nominal_perf: Return address.
1151  *
1152  * Return: 0 for success, -EIO otherwise.
1153  */
1154 int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
1155 {
1156         return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
1157 }
1158
1159 /**
1160  * cppc_get_perf_caps - Get a CPU's performance capabilities.
1161  * @cpunum: CPU from which to get capabilities info.
1162  * @perf_caps: ptr to cppc_perf_caps. See cppc_acpi.h
1163  *
1164  * Return: 0 for success with perf_caps populated else -ERRNO.
1165  */
1166 int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
1167 {
1168         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1169         struct cpc_register_resource *highest_reg, *lowest_reg,
1170                 *lowest_non_linear_reg, *nominal_reg, *guaranteed_reg,
1171                 *low_freq_reg = NULL, *nom_freq_reg = NULL;
1172         u64 high, low, guaranteed, nom, min_nonlinear, low_f = 0, nom_f = 0;
1173         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1174         struct cppc_pcc_data *pcc_ss_data = NULL;
1175         int ret = 0, regs_in_pcc = 0;
1176
1177         if (!cpc_desc) {
1178                 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1179                 return -ENODEV;
1180         }
1181
1182         highest_reg = &cpc_desc->cpc_regs[HIGHEST_PERF];
1183         lowest_reg = &cpc_desc->cpc_regs[LOWEST_PERF];
1184         lowest_non_linear_reg = &cpc_desc->cpc_regs[LOW_NON_LINEAR_PERF];
1185         nominal_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
1186         low_freq_reg = &cpc_desc->cpc_regs[LOWEST_FREQ];
1187         nom_freq_reg = &cpc_desc->cpc_regs[NOMINAL_FREQ];
1188         guaranteed_reg = &cpc_desc->cpc_regs[GUARANTEED_PERF];
1189
1190         /* Are any of the regs PCC ?*/
1191         if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
1192                 CPC_IN_PCC(lowest_non_linear_reg) || CPC_IN_PCC(nominal_reg) ||
1193                 CPC_IN_PCC(low_freq_reg) || CPC_IN_PCC(nom_freq_reg)) {
1194                 if (pcc_ss_id < 0) {
1195                         pr_debug("Invalid pcc_ss_id\n");
1196                         return -ENODEV;
1197                 }
1198                 pcc_ss_data = pcc_data[pcc_ss_id];
1199                 regs_in_pcc = 1;
1200                 down_write(&pcc_ss_data->pcc_lock);
1201                 /* Ring doorbell once to update PCC subspace */
1202                 if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
1203                         ret = -EIO;
1204                         goto out_err;
1205                 }
1206         }
1207
1208         cpc_read(cpunum, highest_reg, &high);
1209         perf_caps->highest_perf = high;
1210
1211         cpc_read(cpunum, lowest_reg, &low);
1212         perf_caps->lowest_perf = low;
1213
1214         cpc_read(cpunum, nominal_reg, &nom);
1215         perf_caps->nominal_perf = nom;
1216
1217         if (guaranteed_reg->type != ACPI_TYPE_BUFFER  ||
1218             IS_NULL_REG(&guaranteed_reg->cpc_entry.reg)) {
1219                 perf_caps->guaranteed_perf = 0;
1220         } else {
1221                 cpc_read(cpunum, guaranteed_reg, &guaranteed);
1222                 perf_caps->guaranteed_perf = guaranteed;
1223         }
1224
1225         cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear);
1226         perf_caps->lowest_nonlinear_perf = min_nonlinear;
1227
1228         if (!high || !low || !nom || !min_nonlinear)
1229                 ret = -EFAULT;
1230
1231         /* Read optional lowest and nominal frequencies if present */
1232         if (CPC_SUPPORTED(low_freq_reg))
1233                 cpc_read(cpunum, low_freq_reg, &low_f);
1234
1235         if (CPC_SUPPORTED(nom_freq_reg))
1236                 cpc_read(cpunum, nom_freq_reg, &nom_f);
1237
1238         perf_caps->lowest_freq = low_f;
1239         perf_caps->nominal_freq = nom_f;
1240
1241
1242 out_err:
1243         if (regs_in_pcc)
1244                 up_write(&pcc_ss_data->pcc_lock);
1245         return ret;
1246 }
1247 EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
1248
1249 /**
1250  * cppc_get_perf_ctrs - Read a CPU's performance feedback counters.
1251  * @cpunum: CPU from which to read counters.
1252  * @perf_fb_ctrs: ptr to cppc_perf_fb_ctrs. See cppc_acpi.h
1253  *
1254  * Return: 0 for success with perf_fb_ctrs populated else -ERRNO.
1255  */
1256 int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
1257 {
1258         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1259         struct cpc_register_resource *delivered_reg, *reference_reg,
1260                 *ref_perf_reg, *ctr_wrap_reg;
1261         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1262         struct cppc_pcc_data *pcc_ss_data = NULL;
1263         u64 delivered, reference, ref_perf, ctr_wrap_time;
1264         int ret = 0, regs_in_pcc = 0;
1265
1266         if (!cpc_desc) {
1267                 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1268                 return -ENODEV;
1269         }
1270
1271         delivered_reg = &cpc_desc->cpc_regs[DELIVERED_CTR];
1272         reference_reg = &cpc_desc->cpc_regs[REFERENCE_CTR];
1273         ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
1274         ctr_wrap_reg = &cpc_desc->cpc_regs[CTR_WRAP_TIME];
1275
1276         /*
1277          * If reference perf register is not supported then we should
1278          * use the nominal perf value
1279          */
1280         if (!CPC_SUPPORTED(ref_perf_reg))
1281                 ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
1282
1283         /* Are any of the regs PCC ?*/
1284         if (CPC_IN_PCC(delivered_reg) || CPC_IN_PCC(reference_reg) ||
1285                 CPC_IN_PCC(ctr_wrap_reg) || CPC_IN_PCC(ref_perf_reg)) {
1286                 if (pcc_ss_id < 0) {
1287                         pr_debug("Invalid pcc_ss_id\n");
1288                         return -ENODEV;
1289                 }
1290                 pcc_ss_data = pcc_data[pcc_ss_id];
1291                 down_write(&pcc_ss_data->pcc_lock);
1292                 regs_in_pcc = 1;
1293                 /* Ring doorbell once to update PCC subspace */
1294                 if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
1295                         ret = -EIO;
1296                         goto out_err;
1297                 }
1298         }
1299
1300         cpc_read(cpunum, delivered_reg, &delivered);
1301         cpc_read(cpunum, reference_reg, &reference);
1302         cpc_read(cpunum, ref_perf_reg, &ref_perf);
1303
1304         /*
1305          * Per spec, if ctr_wrap_time optional register is unsupported, then the
1306          * performance counters are assumed to never wrap during the lifetime of
1307          * platform
1308          */
1309         ctr_wrap_time = (u64)(~((u64)0));
1310         if (CPC_SUPPORTED(ctr_wrap_reg))
1311                 cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);
1312
1313         if (!delivered || !reference || !ref_perf) {
1314                 ret = -EFAULT;
1315                 goto out_err;
1316         }
1317
1318         perf_fb_ctrs->delivered = delivered;
1319         perf_fb_ctrs->reference = reference;
1320         perf_fb_ctrs->reference_perf = ref_perf;
1321         perf_fb_ctrs->wraparound_time = ctr_wrap_time;
1322 out_err:
1323         if (regs_in_pcc)
1324                 up_write(&pcc_ss_data->pcc_lock);
1325         return ret;
1326 }
1327 EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
1328
1329 /**
1330  * cppc_set_enable - Set to enable CPPC on the processor by writing the
1331  * Continuous Performance Control package EnableRegister field.
1332  * @cpu: CPU for which to enable CPPC register.
1333  * @enable: 0 - disable, 1 - enable CPPC feature on the processor.
1334  *
1335  * Return: 0 for success, -ERRNO or -EIO otherwise.
1336  */
1337 int cppc_set_enable(int cpu, bool enable)
1338 {
1339         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1340         struct cpc_register_resource *enable_reg;
1341         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1342         struct cppc_pcc_data *pcc_ss_data = NULL;
1343         int ret = -EINVAL;
1344
1345         if (!cpc_desc) {
1346                 pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1347                 return -EINVAL;
1348         }
1349
1350         enable_reg = &cpc_desc->cpc_regs[ENABLE];
1351
1352         if (CPC_IN_PCC(enable_reg)) {
1353
1354                 if (pcc_ss_id < 0)
1355                         return -EIO;
1356
1357                 ret = cpc_write(cpu, enable_reg, enable);
1358                 if (ret)
1359                         return ret;
1360
1361                 pcc_ss_data = pcc_data[pcc_ss_id];
1362
1363                 down_write(&pcc_ss_data->pcc_lock);
1364                 /* after writing CPC, transfer the ownership of PCC to platfrom */
1365                 ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
1366                 up_write(&pcc_ss_data->pcc_lock);
1367                 return ret;
1368         }
1369
1370         return cpc_write(cpu, enable_reg, enable);
1371 }
1372 EXPORT_SYMBOL_GPL(cppc_set_enable);
1373
1374 /**
1375  * cppc_set_perf - Set a CPU's performance controls.
1376  * @cpu: CPU for which to set performance controls.
1377  * @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
1378  *
1379  * Return: 0 for success, -ERRNO otherwise.
1380  */
1381 int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
1382 {
1383         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1384         struct cpc_register_resource *desired_reg;
1385         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1386         struct cppc_pcc_data *pcc_ss_data = NULL;
1387         int ret = 0;
1388
1389         if (!cpc_desc) {
1390                 pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1391                 return -ENODEV;
1392         }
1393
1394         desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
1395
1396         /*
1397          * This is Phase-I where we want to write to CPC registers
1398          * -> We want all CPUs to be able to execute this phase in parallel
1399          *
1400          * Since read_lock can be acquired by multiple CPUs simultaneously we
1401          * achieve that goal here
1402          */
1403         if (CPC_IN_PCC(desired_reg)) {
1404                 if (pcc_ss_id < 0) {
1405                         pr_debug("Invalid pcc_ss_id\n");
1406                         return -ENODEV;
1407                 }
1408                 pcc_ss_data = pcc_data[pcc_ss_id];
1409                 down_read(&pcc_ss_data->pcc_lock); /* BEGIN Phase-I */
1410                 if (pcc_ss_data->platform_owns_pcc) {
1411                         ret = check_pcc_chan(pcc_ss_id, false);
1412                         if (ret) {
1413                                 up_read(&pcc_ss_data->pcc_lock);
1414                                 return ret;
1415                         }
1416                 }
1417                 /*
1418                  * Update the pending_write to make sure a PCC CMD_READ will not
1419                  * arrive and steal the channel during the switch to write lock
1420                  */
1421                 pcc_ss_data->pending_pcc_write_cmd = true;
1422                 cpc_desc->write_cmd_id = pcc_ss_data->pcc_write_cnt;
1423                 cpc_desc->write_cmd_status = 0;
1424         }
1425
1426         /*
1427          * Skip writing MIN/MAX until Linux knows how to come up with
1428          * useful values.
1429          */
1430         cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);
1431
1432         if (CPC_IN_PCC(desired_reg))
1433                 up_read(&pcc_ss_data->pcc_lock);        /* END Phase-I */
1434         /*
1435          * This is Phase-II where we transfer the ownership of PCC to Platform
1436          *
1437          * Short Summary: Basically if we think of a group of cppc_set_perf
1438          * requests that happened in short overlapping interval. The last CPU to
1439          * come out of Phase-I will enter Phase-II and ring the doorbell.
1440          *
1441          * We have the following requirements for Phase-II:
1442          *     1. We want to execute Phase-II only when there are no CPUs
1443          * currently executing in Phase-I
1444          *     2. Once we start Phase-II we want to avoid all other CPUs from
1445          * entering Phase-I.
1446          *     3. We want only one CPU among all those who went through Phase-I
1447          * to run phase-II
1448          *
1449          * If write_trylock fails to get the lock and doesn't transfer the
1450          * PCC ownership to the platform, then one of the following will be TRUE
1451          *     1. There is at-least one CPU in Phase-I which will later execute
1452          * write_trylock, so the CPUs in Phase-I will be responsible for
1453          * executing the Phase-II.
1454          *     2. Some other CPU has beaten this CPU to successfully execute the
1455          * write_trylock and has already acquired the write_lock. We know for a
1456          * fact it (other CPU acquiring the write_lock) couldn't have happened
1457          * before this CPU's Phase-I as we held the read_lock.
1458          *     3. Some other CPU executing pcc CMD_READ has stolen the
1459          * down_write, in which case, send_pcc_cmd will check for pending
1460          * CMD_WRITE commands by checking the pending_pcc_write_cmd.
1461          * So this CPU can be certain that its request will be delivered
1462          *    So in all cases, this CPU knows that its request will be delivered
1463          * by another CPU and can return
1464          *
1465          * After getting the down_write we still need to check for
1466          * pending_pcc_write_cmd to take care of the following scenario
1467          *    The thread running this code could be scheduled out between
1468          * Phase-I and Phase-II. Before it is scheduled back on, another CPU
1469          * could have delivered the request to Platform by triggering the
1470          * doorbell and transferred the ownership of PCC to platform. So this
1471          * avoids triggering an unnecessary doorbell and more importantly before
1472          * triggering the doorbell it makes sure that the PCC channel ownership
1473          * is still with OSPM.
1474          *   pending_pcc_write_cmd can also be cleared by a different CPU, if
1475          * there was a pcc CMD_READ waiting on down_write and it steals the lock
1476          * before the pcc CMD_WRITE is completed. send_pcc_cmd checks for this
1477          * case during a CMD_READ and if there are pending writes it delivers
1478          * the write command before servicing the read command
1479          */
1480         if (CPC_IN_PCC(desired_reg)) {
1481                 if (down_write_trylock(&pcc_ss_data->pcc_lock)) {/* BEGIN Phase-II */
1482                         /* Update only if there are pending write commands */
1483                         if (pcc_ss_data->pending_pcc_write_cmd)
1484                                 send_pcc_cmd(pcc_ss_id, CMD_WRITE);
1485                         up_write(&pcc_ss_data->pcc_lock);       /* END Phase-II */
1486                 } else
1487                         /* Wait until pcc_write_cnt is updated by send_pcc_cmd */
1488                         wait_event(pcc_ss_data->pcc_write_wait_q,
1489                                    cpc_desc->write_cmd_id != pcc_ss_data->pcc_write_cnt);
1490
1491                 /* send_pcc_cmd updates the status in case of failure */
1492                 ret = cpc_desc->write_cmd_status;
1493         }
1494         return ret;
1495 }
1496 EXPORT_SYMBOL_GPL(cppc_set_perf);
1497
1498 /**
1499  * cppc_get_transition_latency - returns frequency transition latency in ns
1500  *
1501  * ACPI CPPC does not explicitly specify how a platform can specify the
1502  * transition latency for performance change requests. The closest we have
1503  * is the timing information from the PCCT tables which provides the info
1504  * on the number and frequency of PCC commands the platform can handle.
1505  *
1506  * If desired_reg is in the SystemMemory or SystemIo ACPI address space,
1507  * then assume there is no latency.
1508  */
1509 unsigned int cppc_get_transition_latency(int cpu_num)
1510 {
1511         /*
1512          * Expected transition latency is based on the PCCT timing values
1513          * Below are definition from ACPI spec:
1514          * pcc_nominal- Expected latency to process a command, in microseconds
1515          * pcc_mpar   - The maximum number of periodic requests that the subspace
1516          *              channel can support, reported in commands per minute. 0
1517          *              indicates no limitation.
1518          * pcc_mrtt   - The minimum amount of time that OSPM must wait after the
1519          *              completion of a command before issuing the next command,
1520          *              in microseconds.
1521          */
1522         unsigned int latency_ns = 0;
1523         struct cpc_desc *cpc_desc;
1524         struct cpc_register_resource *desired_reg;
1525         int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu_num);
1526         struct cppc_pcc_data *pcc_ss_data;
1527
1528         cpc_desc = per_cpu(cpc_desc_ptr, cpu_num);
1529         if (!cpc_desc)
1530                 return CPUFREQ_ETERNAL;
1531
1532         desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
1533         if (CPC_IN_SYSTEM_MEMORY(desired_reg) || CPC_IN_SYSTEM_IO(desired_reg))
1534                 return 0;
1535         else if (!CPC_IN_PCC(desired_reg))
1536                 return CPUFREQ_ETERNAL;
1537
1538         if (pcc_ss_id < 0)
1539                 return CPUFREQ_ETERNAL;
1540
1541         pcc_ss_data = pcc_data[pcc_ss_id];
1542         if (pcc_ss_data->pcc_mpar)
1543                 latency_ns = 60 * (1000 * 1000 * 1000 / pcc_ss_data->pcc_mpar);
1544
1545         latency_ns = max(latency_ns, pcc_ss_data->pcc_nominal * 1000);
1546         latency_ns = max(latency_ns, pcc_ss_data->pcc_mrtt * 1000);
1547
1548         return latency_ns;
1549 }
1550 EXPORT_SYMBOL_GPL(cppc_get_transition_latency);