drivers/acpi/cppc_acpi.c

   1 /*
   2  * CPPC (Collaborative Processor Performance Control) methods used by CPUfreq drivers.
   3  *
   4  * (C) Copyright 2014, 2015 Linaro Ltd.
   5  * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; version 2
  10  * of the License.
  11  *
  12  * CPPC describes a few methods for controlling CPU performance using
  13  * information from a per CPU table called CPC. This table is described in
  14  * the ACPI v5.0+ specification. The table consists of a list of
  15  * registers which may be memory mapped or hardware registers and also may
  16  * include some static integer values.
  17  *
  18  * CPU performance is on an abstract continuous scale as against a discretized
  19  * P-state scale which is tied to CPU frequency only. In brief, the basic
  20  * operation involves:
  21  *
  22  * - OS makes a CPU performance request. (Can provide min and max bounds)
  23  *
  24  * - Platform (such as BMC) is free to optimize request within requested bounds
  25  *   depending on power/thermal budgets etc.
  26  *
  27  * - Platform conveys its decision back to OS
  28  *
  29  * The communication between OS and platform occurs through another medium
  30  * called (PCC) Platform Communication Channel. This is a generic mailbox like
  31  * mechanism which includes doorbell semantics to indicate register updates.
  32  * See drivers/mailbox/pcc.c for details on PCC.
  33  *
  34  * Finer details about the PCC and CPPC spec are available in the ACPI v5.1 and
  35  * above specifications.
  36  */
  37
  38 #define pr_fmt(fmt)     "ACPI CPPC: " fmt
  39
  40 #include <linux/cpufreq.h>
  41 #include <linux/delay.h>
  42 #include <linux/ktime.h>
  43
  44 #include <acpi/cppc_acpi.h>
  45 /*
  46  * Lock to provide mutually exclusive access to the PCC
  47  * channel. e.g. When the remote updates the shared region
  48  * with new data, the reader needs to be protected from
  49  * other CPUs activity on the same channel.
  50  */
  51 static DEFINE_SPINLOCK(pcc_lock);
  52
  53 /*
  54  * The cpc_desc structure contains the ACPI register details
  55  * as described in the per CPU _CPC tables. The details
  56  * include the type of register (e.g. PCC, System IO, FFH etc.)
  57  * and destination addresses which lets us READ/WRITE CPU performance
  58  * information using the appropriate I/O methods.
  59  */
  60 static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
  61
  62 /* This layer handles all the PCC specifics for CPPC. */
  63 static struct mbox_chan *pcc_channel;
  64 static void __iomem *pcc_comm_addr;
  65 static u64 comm_base_addr;
  66 static int pcc_subspace_idx = -1;
  67 static bool pcc_channel_acquired;
  68 static ktime_t deadline;
  69 static unsigned int pcc_mpar, pcc_mrtt;
  70
  71 /* pcc mapped address + header size + offset within PCC subspace */
  72 #define GET_PCC_VADDR(offs) (pcc_comm_addr + 0x8 + (offs))
  73
  74 /*
  75  * Arbitrary Retries in case the remote processor is slow to respond
  76  * to PCC commands. Keeping it high enough to cover emulators where
  77  * the processors run painfully slow.
  78  */
  79 #define NUM_RETRIES 500
  80
  81 static int check_pcc_chan(void)
  82 {
  83         int ret = -EIO;
  84         struct acpi_pcct_shared_memory __iomem *generic_comm_base = pcc_comm_addr;
  85         ktime_t next_deadline = ktime_add(ktime_get(), deadline);
  86
  87         /* Retry in case the remote processor was too slow to catch up. */
  88         while (!ktime_after(ktime_get(), next_deadline)) {
  89                 /*
  90                  * Per spec, prior to boot the PCC space wil be initialized by
  91                  * platform and should have set the command completion bit when
  92                  * PCC can be used by OSPM
  93                  */
  94                 if (readw_relaxed(&generic_comm_base->status) & PCC_CMD_COMPLETE) {
  95                         ret = 0;
  96                         break;
  97                 }
  98                 /*
  99                  * Reducing the bus traffic in case this loop takes longer than
 100                  * a few retries.
 101                  */
 102                 udelay(3);
 103         }
 104
 105         return ret;
 106 }
 107
 108 static int send_pcc_cmd(u16 cmd)
 109 {
 110         int ret = -EIO;
 111         struct acpi_pcct_shared_memory *generic_comm_base =
 112                 (struct acpi_pcct_shared_memory *) pcc_comm_addr;
 113         static ktime_t last_cmd_cmpl_time, last_mpar_reset;
 114         static int mpar_count;
 115         unsigned int time_delta;
 116
 117         /*
 118          * For CMD_WRITE we know for a fact the caller should have checked
 119          * the channel before writing to PCC space
 120          */
 121         if (cmd == CMD_READ) {
 122                 ret = check_pcc_chan();
 123                 if (ret)
 124                         return ret;
 125         }
 126
 127         /*
 128          * Handle the Minimum Request Turnaround Time(MRTT)
 129          * "The minimum amount of time that OSPM must wait after the completion
 130          * of a command before issuing the next command, in microseconds"
 131          */
 132         if (pcc_mrtt) {
 133                 time_delta = ktime_us_delta(ktime_get(), last_cmd_cmpl_time);
 134                 if (pcc_mrtt > time_delta)
 135                         udelay(pcc_mrtt - time_delta);
 136         }
 137
 138         /*
 139          * Handle the non-zero Maximum Periodic Access Rate(MPAR)
 140          * "The maximum number of periodic requests that the subspace channel can
 141          * support, reported in commands per minute. 0 indicates no limitation."
 142          *
 143          * This parameter should be ideally zero or large enough so that it can
 144          * handle maximum number of requests that all the cores in the system can
 145          * collectively generate. If it is not, we will follow the spec and just
 146          * not send the request to the platform after hitting the MPAR limit in
 147          * any 60s window
 148          */
 149         if (pcc_mpar) {
 150                 if (mpar_count == 0) {
 151                         time_delta = ktime_ms_delta(ktime_get(), last_mpar_reset);
 152                         if (time_delta < 60 * MSEC_PER_SEC) {
 153                                 pr_debug("PCC cmd not sent due to MPAR limit");
 154                                 return -EIO;
 155                         }
 156                         last_mpar_reset = ktime_get();
 157                         mpar_count = pcc_mpar;
 158                 }
 159                 mpar_count--;
 160         }
 161
 162         /* Write to the shared comm region. */
 163         writew_relaxed(cmd, &generic_comm_base->command);
 164
 165         /* Flip CMD COMPLETE bit */
 166         writew_relaxed(0, &generic_comm_base->status);
 167
 168         /* Ring doorbell */
 169         ret = mbox_send_message(pcc_channel, &cmd);
 170         if (ret < 0) {
 171                 pr_err("Err sending PCC mbox message. cmd:%d, ret:%d\n",
 172                                 cmd, ret);
 173                 return ret;
 174         }
 175
 176         /*
 177          * For READs we need to ensure the cmd completed to ensure
 178          * the ensuing read()s can proceed. For WRITEs we dont care
 179          * because the actual write()s are done before coming here
 180          * and the next READ or WRITE will check if the channel
 181          * is busy/free at the entry of this call.
 182          *
 183          * If Minimum Request Turnaround Time is non-zero, we need
 184          * to record the completion time of both READ and WRITE
 185          * command for proper handling of MRTT, so we need to check
 186          * for pcc_mrtt in addition to CMD_READ
 187          */
 188         if (cmd == CMD_READ || pcc_mrtt) {
 189                 ret = check_pcc_chan();
 190                 if (pcc_mrtt)
 191                         last_cmd_cmpl_time = ktime_get();
 192         }
 193
 194         mbox_client_txdone(pcc_channel, ret);
 195         return ret;
 196 }
 197
 198 static void cppc_chan_tx_done(struct mbox_client *cl, void *msg, int ret)
 199 {
 200         if (ret < 0)
 201                 pr_debug("TX did not complete: CMD sent:%x, ret:%d\n",
 202                                 *(u16 *)msg, ret);
 203         else
 204                 pr_debug("TX completed. CMD sent:%x, ret:%d\n",
 205                                 *(u16 *)msg, ret);
 206 }
 207
 208 struct mbox_client cppc_mbox_cl = {
 209         .tx_done = cppc_chan_tx_done,
 210         .knows_txdone = true,
 211 };
 212
 213 static int acpi_get_psd(struct cpc_desc *cpc_ptr, acpi_handle handle)
 214 {
 215         int result = -EFAULT;
 216         acpi_status status = AE_OK;
 217         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 218         struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
 219         struct acpi_buffer state = {0, NULL};
 220         union acpi_object  *psd = NULL;
 221         struct acpi_psd_package *pdomain;
 222
 223         status = acpi_evaluate_object_typed(handle, "_PSD", NULL, &buffer,
 224                         ACPI_TYPE_PACKAGE);
 225         if (ACPI_FAILURE(status))
 226                 return -ENODEV;
 227
 228         psd = buffer.pointer;
 229         if (!psd || psd->package.count != 1) {
 230                 pr_debug("Invalid _PSD data\n");
 231                 goto end;
 232         }
 233
 234         pdomain = &(cpc_ptr->domain_info);
 235
 236         state.length = sizeof(struct acpi_psd_package);
 237         state.pointer = pdomain;
 238
 239         status = acpi_extract_package(&(psd->package.elements[0]),
 240                 &format, &state);
 241         if (ACPI_FAILURE(status)) {
 242                 pr_debug("Invalid _PSD data for CPU:%d\n", cpc_ptr->cpu_id);
 243                 goto end;
 244         }
 245
 246         if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
 247                 pr_debug("Unknown _PSD:num_entries for CPU:%d\n", cpc_ptr->cpu_id);
 248                 goto end;
 249         }
 250
 251         if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
 252                 pr_debug("Unknown _PSD:revision for CPU: %d\n", cpc_ptr->cpu_id);
 253                 goto end;
 254         }
 255
 256         if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
 257             pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
 258             pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
 259                 pr_debug("Invalid _PSD:coord_type for CPU:%d\n", cpc_ptr->cpu_id);
 260                 goto end;
 261         }
 262
 263         result = 0;
 264 end:
 265         kfree(buffer.pointer);
 266         return result;
 267 }
 268
 269 /**
 270  * acpi_get_psd_map - Map the CPUs in a common freq domain.
 271  * @all_cpu_data: Ptrs to CPU specific CPPC data including PSD info.
 272  *
 273  *      Return: 0 for success or negative value for err.
 274  */
 275 int acpi_get_psd_map(struct cpudata **all_cpu_data)
 276 {
 277         int count_target;
 278         int retval = 0;
 279         unsigned int i, j;
 280         cpumask_var_t covered_cpus;
 281         struct cpudata *pr, *match_pr;
 282         struct acpi_psd_package *pdomain;
 283         struct acpi_psd_package *match_pdomain;
 284         struct cpc_desc *cpc_ptr, *match_cpc_ptr;
 285
 286         if (!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))
 287                 return -ENOMEM;
 288
 289         /*
 290          * Now that we have _PSD data from all CPUs, lets setup P-state
 291          * domain info.
 292          */
 293         for_each_possible_cpu(i) {
 294                 pr = all_cpu_data[i];
 295                 if (!pr)
 296                         continue;
 297
 298                 if (cpumask_test_cpu(i, covered_cpus))
 299                         continue;
 300
 301                 cpc_ptr = per_cpu(cpc_desc_ptr, i);
 302                 if (!cpc_ptr)
 303                         continue;
 304
 305                 pdomain = &(cpc_ptr->domain_info);
 306                 cpumask_set_cpu(i, pr->shared_cpu_map);
 307                 cpumask_set_cpu(i, covered_cpus);
 308                 if (pdomain->num_processors <= 1)
 309                         continue;
 310
 311                 /* Validate the Domain info */
 312                 count_target = pdomain->num_processors;
 313                 if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
 314                         pr->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 315                 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
 316                         pr->shared_type = CPUFREQ_SHARED_TYPE_HW;
 317                 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
 318                         pr->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 319
 320                 for_each_possible_cpu(j) {
 321                         if (i == j)
 322                                 continue;
 323
 324                         match_cpc_ptr = per_cpu(cpc_desc_ptr, j);
 325                         if (!match_cpc_ptr)
 326                                 continue;
 327
 328                         match_pdomain = &(match_cpc_ptr->domain_info);
 329                         if (match_pdomain->domain != pdomain->domain)
 330                                 continue;
 331
 332                         /* Here i and j are in the same domain */
 333                         if (match_pdomain->num_processors != count_target) {
 334                                 retval = -EFAULT;
 335                                 goto err_ret;
 336                         }
 337
 338                         if (pdomain->coord_type != match_pdomain->coord_type) {
 339                                 retval = -EFAULT;
 340                                 goto err_ret;
 341                         }
 342
 343                         cpumask_set_cpu(j, covered_cpus);
 344                         cpumask_set_cpu(j, pr->shared_cpu_map);
 345                 }
 346
 347                 for_each_possible_cpu(j) {
 348                         if (i == j)
 349                                 continue;
 350
 351                         match_pr = all_cpu_data[j];
 352                         if (!match_pr)
 353                                 continue;
 354
 355                         match_cpc_ptr = per_cpu(cpc_desc_ptr, j);
 356                         if (!match_cpc_ptr)
 357                                 continue;
 358
 359                         match_pdomain = &(match_cpc_ptr->domain_info);
 360                         if (match_pdomain->domain != pdomain->domain)
 361                                 continue;
 362
 363                         match_pr->shared_type = pr->shared_type;
 364                         cpumask_copy(match_pr->shared_cpu_map,
 365                                      pr->shared_cpu_map);
 366                 }
 367         }
 368
 369 err_ret:
 370         for_each_possible_cpu(i) {
 371                 pr = all_cpu_data[i];
 372                 if (!pr)
 373                         continue;
 374
 375                 /* Assume no coordination on any error parsing domain info */
 376                 if (retval) {
 377                         cpumask_clear(pr->shared_cpu_map);
 378                         cpumask_set_cpu(i, pr->shared_cpu_map);
 379                         pr->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 380                 }
 381         }
 382
 383         free_cpumask_var(covered_cpus);
 384         return retval;
 385 }
 386 EXPORT_SYMBOL_GPL(acpi_get_psd_map);
 387
 388 static int register_pcc_channel(int pcc_subspace_idx)
 389 {
 390         struct acpi_pcct_hw_reduced *cppc_ss;
 391         unsigned int len;
 392         u64 usecs_lat;
 393
 394         if (pcc_subspace_idx >= 0) {
 395                 pcc_channel = pcc_mbox_request_channel(&cppc_mbox_cl,
 396                                 pcc_subspace_idx);
 397
 398                 if (IS_ERR(pcc_channel)) {
 399                         pr_err("Failed to find PCC communication channel\n");
 400                         return -ENODEV;
 401                 }
 402
 403                 /*
 404                  * The PCC mailbox controller driver should
 405                  * have parsed the PCCT (global table of all
 406                  * PCC channels) and stored pointers to the
 407                  * subspace communication region in con_priv.
 408                  */
 409                 cppc_ss = pcc_channel->con_priv;
 410
 411                 if (!cppc_ss) {
 412                         pr_err("No PCC subspace found for CPPC\n");
 413                         return -ENODEV;
 414                 }
 415
 416                 /*
 417                  * This is the shared communication region
 418                  * for the OS and Platform to communicate over.
 419                  */
 420                 comm_base_addr = cppc_ss->base_address;
 421                 len = cppc_ss->length;
 422
 423                 /*
 424                  * cppc_ss->latency is just a Nominal value. In reality
 425                  * the remote processor could be much slower to reply.
 426                  * So add an arbitrary amount of wait on top of Nominal.
 427                  */
 428                 usecs_lat = NUM_RETRIES * cppc_ss->latency;
 429                 deadline = ns_to_ktime(usecs_lat * NSEC_PER_USEC);
 430                 pcc_mrtt = cppc_ss->min_turnaround_time;
 431                 pcc_mpar = cppc_ss->max_access_rate;
 432
 433                 pcc_comm_addr = acpi_os_ioremap(comm_base_addr, len);
 434                 if (!pcc_comm_addr) {
 435                         pr_err("Failed to ioremap PCC comm region mem\n");
 436                         return -ENOMEM;
 437                 }
 438
 439                 /* Set flag so that we dont come here for each CPU. */
 440                 pcc_channel_acquired = true;
 441         }
 442
 443         return 0;
 444 }
 445
 446 /*
 447  * An example CPC table looks like the following.
 448  *
 449  *      Name(_CPC, Package()
 450  *                      {
 451  *                      17,
 452  *                      NumEntries
 453  *                      1,
 454  *                      // Revision
 455  *                      ResourceTemplate(){Register(PCC, 32, 0, 0x120, 2)},
 456  *                      // Highest Performance
 457  *                      ResourceTemplate(){Register(PCC, 32, 0, 0x124, 2)},
 458  *                      // Nominal Performance
 459  *                      ResourceTemplate(){Register(PCC, 32, 0, 0x128, 2)},
 460  *                      // Lowest Nonlinear Performance
 461  *                      ResourceTemplate(){Register(PCC, 32, 0, 0x12C, 2)},
 462  *                      // Lowest Performance
 463  *                      ResourceTemplate(){Register(PCC, 32, 0, 0x130, 2)},
 464  *                      // Guaranteed Performance Register
 465  *                      ResourceTemplate(){Register(PCC, 32, 0, 0x110, 2)},
 466  *                      // Desired Performance Register
 467  *                      ResourceTemplate(){Register(SystemMemory, 0, 0, 0, 0)},
 468  *                      ..
 469  *                      ..
 470  *                      ..
 471  *
 472  *              }
 473  * Each Register() encodes how to access that specific register.
 474  * e.g. a sample PCC entry has the following encoding:
 475  *
 476  *      Register (
 477  *              PCC,
 478  *              AddressSpaceKeyword
 479  *              8,
 480  *              //RegisterBitWidth
 481  *              8,
 482  *              //RegisterBitOffset
 483  *              0x30,
 484  *              //RegisterAddress
 485  *              9
 486  *              //AccessSize (subspace ID)
 487  *              0
 488  *              )
 489  *      }
 490  */
 491
 492 /**
 493  * acpi_cppc_processor_probe - Search for per CPU _CPC objects.
 494  * @pr: Ptr to acpi_processor containing this CPUs logical Id.
 495  *
 496  *      Return: 0 for success or negative value for err.
 497  */
 498 int acpi_cppc_processor_probe(struct acpi_processor *pr)
 499 {
 500         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 501         union acpi_object *out_obj, *cpc_obj;
 502         struct cpc_desc *cpc_ptr;
 503         struct cpc_reg *gas_t;
 504         acpi_handle handle = pr->handle;
 505         unsigned int num_ent, i, cpc_rev;
 506         acpi_status status;
 507         int ret = -EFAULT;
 508
 509         /* Parse the ACPI _CPC table for this cpu. */
 510         status = acpi_evaluate_object_typed(handle, "_CPC", NULL, &output,
 511                         ACPI_TYPE_PACKAGE);
 512         if (ACPI_FAILURE(status)) {
 513                 ret = -ENODEV;
 514                 goto out_buf_free;
 515         }
 516
 517         out_obj = (union acpi_object *) output.pointer;
 518
 519         cpc_ptr = kzalloc(sizeof(struct cpc_desc), GFP_KERNEL);
 520         if (!cpc_ptr) {
 521                 ret = -ENOMEM;
 522                 goto out_buf_free;
 523         }
 524
 525         /* First entry is NumEntries. */
 526         cpc_obj = &out_obj->package.elements[0];
 527         if (cpc_obj->type == ACPI_TYPE_INTEGER) {
 528                 num_ent = cpc_obj->integer.value;
 529         } else {
 530                 pr_debug("Unexpected entry type(%d) for NumEntries\n",
 531                                 cpc_obj->type);
 532                 goto out_free;
 533         }
 534
 535         /* Only support CPPCv2. Bail otherwise. */
 536         if (num_ent != CPPC_NUM_ENT) {
 537                 pr_debug("Firmware exports %d entries. Expected: %d\n",
 538                                 num_ent, CPPC_NUM_ENT);
 539                 goto out_free;
 540         }
 541
 542         /* Second entry should be revision. */
 543         cpc_obj = &out_obj->package.elements[1];
 544         if (cpc_obj->type == ACPI_TYPE_INTEGER) {
 545                 cpc_rev = cpc_obj->integer.value;
 546         } else {
 547                 pr_debug("Unexpected entry type(%d) for Revision\n",
 548                                 cpc_obj->type);
 549                 goto out_free;
 550         }
 551
 552         if (cpc_rev != CPPC_REV) {
 553                 pr_debug("Firmware exports revision:%d. Expected:%d\n",
 554                                 cpc_rev, CPPC_REV);
 555                 goto out_free;
 556         }
 557
 558         /* Iterate through remaining entries in _CPC */
 559         for (i = 2; i < num_ent; i++) {
 560                 cpc_obj = &out_obj->package.elements[i];
 561
 562                 if (cpc_obj->type == ACPI_TYPE_INTEGER) {
 563                         cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_INTEGER;
 564                         cpc_ptr->cpc_regs[i-2].cpc_entry.int_value = cpc_obj->integer.value;
 565                 } else if (cpc_obj->type == ACPI_TYPE_BUFFER) {
 566                         gas_t = (struct cpc_reg *)
 567                                 cpc_obj->buffer.pointer;
 568
 569                         /*
 570                          * The PCC Subspace index is encoded inside
 571                          * the CPC table entries. The same PCC index
 572                          * will be used for all the PCC entries,
 573                          * so extract it only once.
 574                          */
 575                         if (gas_t->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
 576                                 if (pcc_subspace_idx < 0)
 577                                         pcc_subspace_idx = gas_t->access_width;
 578                                 else if (pcc_subspace_idx != gas_t->access_width) {
 579                                         pr_debug("Mismatched PCC ids.\n");
 580                                         goto out_free;
 581                                 }
 582                         } else if (gas_t->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 583                                 /* Support only PCC and SYS MEM type regs */
 584                                 pr_debug("Unsupported register type: %d\n", gas_t->space_id);
 585                                 goto out_free;
 586                         }
 587
 588                         cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_BUFFER;
 589                         memcpy(&cpc_ptr->cpc_regs[i-2].cpc_entry.reg, gas_t, sizeof(*gas_t));
 590                 } else {
 591                         pr_debug("Err in entry:%d in CPC table of CPU:%d \n", i, pr->id);
 592                         goto out_free;
 593                 }
 594         }
 595         /* Store CPU Logical ID */
 596         cpc_ptr->cpu_id = pr->id;
 597
 598         /* Plug it into this CPUs CPC descriptor. */
 599         per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
 600
 601         /* Parse PSD data for this CPU */
 602         ret = acpi_get_psd(cpc_ptr, handle);
 603         if (ret)
 604                 goto out_free;
 605
 606         /* Register PCC channel once for all CPUs. */
 607         if (!pcc_channel_acquired) {
 608                 ret = register_pcc_channel(pcc_subspace_idx);
 609                 if (ret)
 610                         goto out_free;
 611         }
 612
 613         /* Everything looks okay */
 614         pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);
 615
 616         kfree(output.pointer);
 617         return 0;
 618
 619 out_free:
 620         kfree(cpc_ptr);
 621
 622 out_buf_free:
 623         kfree(output.pointer);
 624         return ret;
 625 }
 626 EXPORT_SYMBOL_GPL(acpi_cppc_processor_probe);
 627
 628 /**
 629  * acpi_cppc_processor_exit - Cleanup CPC structs.
 630  * @pr: Ptr to acpi_processor containing this CPUs logical Id.
 631  *
 632  * Return: Void
 633  */
 634 void acpi_cppc_processor_exit(struct acpi_processor *pr)
 635 {
 636         struct cpc_desc *cpc_ptr;
 637         cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
 638         kfree(cpc_ptr);
 639 }
 640 EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
 641
 642 /*
 643  * Since cpc_read and cpc_write are called while holding pcc_lock, it should be
 644  * as fast as possible. We have already mapped the PCC subspace during init, so
 645  * we can directly write to it.
 646  */
 647
 648 static int cpc_read(struct cpc_reg *reg, u64 *val)
 649 {
 650         int ret_val = 0;
 651
 652         *val = 0;
 653         if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
 654                 void __iomem *vaddr = GET_PCC_VADDR(reg->address);
 655
 656                 switch (reg->bit_width) {
 657                 case 8:
 658                         *val = readb_relaxed(vaddr);
 659                         break;
 660                 case 16:
 661                         *val = readw_relaxed(vaddr);
 662                         break;
 663                 case 32:
 664                         *val = readl_relaxed(vaddr);
 665                         break;
 666                 case 64:
 667                         *val = readq_relaxed(vaddr);
 668                         break;
 669                 default:
 670                         pr_debug("Error: Cannot read %u bit width from PCC\n",
 671                                 reg->bit_width);
 672                         ret_val = -EFAULT;
 673                 }
 674         } else
 675                 ret_val = acpi_os_read_memory((acpi_physical_address)reg->address,
 676                                         val, reg->bit_width);
 677         return ret_val;
 678 }
 679
 680 static int cpc_write(struct cpc_reg *reg, u64 val)
 681 {
 682         int ret_val = 0;
 683
 684         if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
 685                 void __iomem *vaddr = GET_PCC_VADDR(reg->address);
 686
 687                 switch (reg->bit_width) {
 688                 case 8:
 689                         writeb_relaxed(val, vaddr);
 690                         break;
 691                 case 16:
 692                         writew_relaxed(val, vaddr);
 693                         break;
 694                 case 32:
 695                         writel_relaxed(val, vaddr);
 696                         break;
 697                 case 64:
 698                         writeq_relaxed(val, vaddr);
 699                         break;
 700                 default:
 701                         pr_debug("Error: Cannot write %u bit width to PCC\n",
 702                                 reg->bit_width);
 703                         ret_val = -EFAULT;
 704                         break;
 705                 }
 706         } else
 707                 ret_val = acpi_os_write_memory((acpi_physical_address)reg->address,
 708                                 val, reg->bit_width);
 709         return ret_val;
 710 }
 711
 712 /**
 713  * cppc_get_perf_caps - Get a CPUs performance capabilities.
 714  * @cpunum: CPU from which to get capabilities info.
 715  * @perf_caps: ptr to cppc_perf_caps. See cppc_acpi.h
 716  *
 717  * Return: 0 for success with perf_caps populated else -ERRNO.
 718  */
 719 int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 720 {
 721         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
 722         struct cpc_register_resource *highest_reg, *lowest_reg, *ref_perf,
 723                                                                  *nom_perf;
 724         u64 high, low, ref, nom;
 725         int ret = 0;
 726
 727         if (!cpc_desc) {
 728                 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
 729                 return -ENODEV;
 730         }
 731
 732         highest_reg = &cpc_desc->cpc_regs[HIGHEST_PERF];
 733         lowest_reg = &cpc_desc->cpc_regs[LOWEST_PERF];
 734         ref_perf = &cpc_desc->cpc_regs[REFERENCE_PERF];
 735         nom_perf = &cpc_desc->cpc_regs[NOMINAL_PERF];
 736
 737         spin_lock(&pcc_lock);
 738
 739         /* Are any of the regs PCC ?*/
 740         if ((highest_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
 741                         (lowest_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
 742                         (ref_perf->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
 743                         (nom_perf->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM)) {
 744                 /* Ring doorbell once to update PCC subspace */
 745                 if (send_pcc_cmd(CMD_READ) < 0) {
 746                         ret = -EIO;
 747                         goto out_err;
 748                 }
 749         }
 750
 751         cpc_read(&highest_reg->cpc_entry.reg, &high);
 752         perf_caps->highest_perf = high;
 753
 754         cpc_read(&lowest_reg->cpc_entry.reg, &low);
 755         perf_caps->lowest_perf = low;
 756
 757         cpc_read(&ref_perf->cpc_entry.reg, &ref);
 758         perf_caps->reference_perf = ref;
 759
 760         cpc_read(&nom_perf->cpc_entry.reg, &nom);
 761         perf_caps->nominal_perf = nom;
 762
 763         if (!ref)
 764                 perf_caps->reference_perf = perf_caps->nominal_perf;
 765
 766         if (!high || !low || !nom)
 767                 ret = -EFAULT;
 768
 769 out_err:
 770         spin_unlock(&pcc_lock);
 771         return ret;
 772 }
 773 EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
 774
 775 /**
 776  * cppc_get_perf_ctrs - Read a CPUs performance feedback counters.
 777  * @cpunum: CPU from which to read counters.
 778  * @perf_fb_ctrs: ptr to cppc_perf_fb_ctrs. See cppc_acpi.h
 779  *
 780  * Return: 0 for success with perf_fb_ctrs populated else -ERRNO.
 781  */
 782 int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 783 {
 784         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
 785         struct cpc_register_resource *delivered_reg, *reference_reg;
 786         u64 delivered, reference;
 787         int ret = 0;
 788
 789         if (!cpc_desc) {
 790                 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
 791                 return -ENODEV;
 792         }
 793
 794         delivered_reg = &cpc_desc->cpc_regs[DELIVERED_CTR];
 795         reference_reg = &cpc_desc->cpc_regs[REFERENCE_CTR];
 796
 797         spin_lock(&pcc_lock);
 798
 799         /* Are any of the regs PCC ?*/
 800         if ((delivered_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
 801                         (reference_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM)) {
 802                 /* Ring doorbell once to update PCC subspace */
 803                 if (send_pcc_cmd(CMD_READ) < 0) {
 804                         ret = -EIO;
 805                         goto out_err;
 806                 }
 807         }
 808
 809         cpc_read(&delivered_reg->cpc_entry.reg, &delivered);
 810         cpc_read(&reference_reg->cpc_entry.reg, &reference);
 811
 812         if (!delivered || !reference) {
 813                 ret = -EFAULT;
 814                 goto out_err;
 815         }
 816
 817         perf_fb_ctrs->delivered = delivered;
 818         perf_fb_ctrs->reference = reference;
 819
 820         perf_fb_ctrs->delivered -= perf_fb_ctrs->prev_delivered;
 821         perf_fb_ctrs->reference -= perf_fb_ctrs->prev_reference;
 822
 823         perf_fb_ctrs->prev_delivered = delivered;
 824         perf_fb_ctrs->prev_reference = reference;
 825
 826 out_err:
 827         spin_unlock(&pcc_lock);
 828         return ret;
 829 }
 830 EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
 831
 832 /**
 833  * cppc_set_perf - Set a CPUs performance controls.
 834  * @cpu: CPU for which to set performance controls.
 835  * @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
 836  *
 837  * Return: 0 for success, -ERRNO otherwise.
 838  */
 839 int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 840 {
 841         struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
 842         struct cpc_register_resource *desired_reg;
 843         int ret = 0;
 844
 845         if (!cpc_desc) {
 846                 pr_debug("No CPC descriptor for CPU:%d\n", cpu);
 847                 return -ENODEV;
 848         }
 849
 850         desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
 851
 852         spin_lock(&pcc_lock);
 853
 854         /* If this is PCC reg, check if channel is free before writing */
 855         if (desired_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
 856                 ret = check_pcc_chan();
 857                 if (ret)
 858                         goto busy_channel;
 859         }
 860
 861         /*
 862          * Skip writing MIN/MAX until Linux knows how to come up with
 863          * useful values.
 864          */
 865         cpc_write(&desired_reg->cpc_entry.reg, perf_ctrls->desired_perf);
 866
 867         /* Is this a PCC reg ?*/
 868         if (desired_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
 869                 /* Ring doorbell so Remote can get our perf request. */
 870                 if (send_pcc_cmd(CMD_WRITE) < 0)
 871                         ret = -EIO;
 872         }
 873 busy_channel:
 874         spin_unlock(&pcc_lock);
 875
 876         return ret;
 877 }
 878 EXPORT_SYMBOL_GPL(cppc_set_perf);