1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2014 Linaro Ltd. 4 * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org> 5 * 6 * PCC (Platform Communication Channel) is defined in the ACPI 5.0+ 7 * specification. It is a mailbox like mechanism to allow clients 8 * such as CPPC (Collaborative Processor Performance Control), RAS 9 * (Reliability, Availability and Serviceability) and MPST (Memory 10 * Node Power State Table) to talk to the platform (e.g. BMC) through 11 * shared memory regions as defined in the PCC table entries. The PCC 12 * specification supports a Doorbell mechanism for the PCC clients 13 * to notify the platform about new data. This Doorbell information 14 * is also specified in each PCC table entry. 15 * 16 * Typical high level flow of operation is: 17 * 18 * PCC Reads: 19 * * Client tries to acquire a channel lock. 20 * * After it is acquired it writes READ cmd in communication region cmd 21 * address. 22 * * Client issues mbox_send_message() which rings the PCC doorbell 23 * for its PCC channel. 24 * * If command completes, then client has control over channel and 25 * it can proceed with its reads. 26 * * Client releases lock. 27 * 28 * PCC Writes: 29 * * Client tries to acquire channel lock. 30 * * Client writes to its communication region after it acquires a 31 * channel lock. 32 * * Client writes WRITE cmd in communication region cmd address. 33 * * Client issues mbox_send_message() which rings the PCC doorbell 34 * for its PCC channel. 35 * * If command completes, then writes have succeeded and it can release 36 * the channel lock. 37 * 38 * There is a Nominal latency defined for each channel which indicates 39 * how long to wait until a command completes. If command is not complete 40 * the client needs to retry or assume failure. 41 * 42 * For more details about PCC, please see the ACPI specification from 43 * http://www.uefi.org/ACPIv5.1 Section 14. 44 * 45 * This file implements PCC as a Mailbox controller and allows for PCC 46 * clients to be implemented as its Mailbox Client Channels. 47 */ 48 49 #include <linux/acpi.h> 50 #include <linux/delay.h> 51 #include <linux/io.h> 52 #include <linux/init.h> 53 #include <linux/interrupt.h> 54 #include <linux/list.h> 55 #include <linux/log2.h> 56 #include <linux/platform_device.h> 57 #include <linux/mailbox_controller.h> 58 #include <linux/mailbox_client.h> 59 #include <linux/io-64-nonatomic-lo-hi.h> 60 #include <acpi/pcc.h> 61 62 #include "mailbox.h" 63 64 #define MBOX_IRQ_NAME "pcc-mbox" 65 66 /** 67 * struct pcc_chan_reg - PCC register bundle 68 * 69 * @vaddr: cached virtual address for this register 70 * @gas: pointer to the generic address structure for this register 71 * @preserve_mask: bitmask to preserve when writing to this register 72 * @set_mask: bitmask to set when writing to this register 73 * @status_mask: bitmask to determine and/or update the status for this register 74 */ 75 struct pcc_chan_reg { 76 void __iomem *vaddr; 77 struct acpi_generic_address *gas; 78 u64 preserve_mask; 79 u64 set_mask; 80 u64 status_mask; 81 }; 82 83 /** 84 * struct pcc_chan_info - PCC channel specific information 85 * 86 * @chan: PCC channel information with Shared Memory Region info 87 * @db: PCC register bundle for the doorbell register 88 * @plat_irq_ack: PCC register bundle for the platform interrupt acknowledge 89 * register 90 * @cmd_complete: PCC register bundle for the command complete check register 91 * @cmd_update: PCC register bundle for the command complete update register 92 * @error: PCC register bundle for the error status register 93 * @plat_irq: platform interrupt 94 * @type: PCC subspace type 95 * @plat_irq_flags: platform interrupt flags 96 * @chan_in_use: this flag is used just to check if the interrupt needs 97 * handling when it is shared. Since only one transfer can occur 98 * at a time and mailbox takes care of locking, this flag can be 99 * accessed without a lock. Note: the type only support the 100 * communication from OSPM to Platform, like type3, use it, and 101 * other types completely ignore it. 102 */ 103 struct pcc_chan_info { 104 struct pcc_mbox_chan chan; 105 struct pcc_chan_reg db; 106 struct pcc_chan_reg plat_irq_ack; 107 struct pcc_chan_reg cmd_complete; 108 struct pcc_chan_reg cmd_update; 109 struct pcc_chan_reg error; 110 int plat_irq; 111 u8 type; 112 unsigned int plat_irq_flags; 113 bool chan_in_use; 114 }; 115 116 #define to_pcc_chan_info(c) container_of(c, struct pcc_chan_info, chan) 117 static struct pcc_chan_info *chan_info; 118 static int pcc_chan_count; 119 120 /* 121 * PCC can be used with perf critical drivers such as CPPC 122 * So it makes sense to locally cache the virtual address and 123 * use it to read/write to PCC registers such as doorbell register 124 * 125 * The below read_register and write_registers are used to read and 126 * write from perf critical registers such as PCC doorbell register 127 */ 128 static void read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width) 129 { 130 switch (bit_width) { 131 case 8: 132 *val = readb(vaddr); 133 break; 134 case 16: 135 *val = readw(vaddr); 136 break; 137 case 32: 138 *val = readl(vaddr); 139 break; 140 case 64: 141 *val = readq(vaddr); 142 break; 143 } 144 } 145 146 static void write_register(void __iomem *vaddr, u64 val, unsigned int bit_width) 147 { 148 switch (bit_width) { 149 case 8: 150 writeb(val, vaddr); 151 break; 152 case 16: 153 writew(val, vaddr); 154 break; 155 case 32: 156 writel(val, vaddr); 157 break; 158 case 64: 159 writeq(val, vaddr); 160 break; 161 } 162 } 163 164 static int pcc_chan_reg_read(struct pcc_chan_reg *reg, u64 *val) 165 { 166 int ret = 0; 167 168 if (!reg->gas) { 169 *val = 0; 170 return 0; 171 } 172 173 if (reg->vaddr) 174 read_register(reg->vaddr, val, reg->gas->bit_width); 175 else 176 ret = acpi_read(val, reg->gas); 177 178 return ret; 179 } 180 181 static int pcc_chan_reg_write(struct pcc_chan_reg *reg, u64 val) 182 { 183 int ret = 0; 184 185 if (!reg->gas) 186 return 0; 187 188 if (reg->vaddr) 189 write_register(reg->vaddr, val, reg->gas->bit_width); 190 else 191 ret = acpi_write(val, reg->gas); 192 193 return ret; 194 } 195 196 static int pcc_chan_reg_read_modify_write(struct pcc_chan_reg *reg) 197 { 198 int ret = 0; 199 u64 val; 200 201 ret = pcc_chan_reg_read(reg, &val); 202 if (ret) 203 return ret; 204 205 val &= reg->preserve_mask; 206 val |= reg->set_mask; 207 208 return pcc_chan_reg_write(reg, val); 209 } 210 211 /** 212 * pcc_map_interrupt - Map a PCC subspace GSI to a linux IRQ number 213 * @interrupt: GSI number. 214 * @flags: interrupt flags 215 * 216 * Returns: a valid linux IRQ number on success 217 * 0 or -EINVAL on failure 218 */ 219 static int pcc_map_interrupt(u32 interrupt, u32 flags) 220 { 221 int trigger, polarity; 222 223 if (!interrupt) 224 return 0; 225 226 trigger = (flags & ACPI_PCCT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE 227 : ACPI_LEVEL_SENSITIVE; 228 229 polarity = (flags & ACPI_PCCT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW 230 : ACPI_ACTIVE_HIGH; 231 232 return acpi_register_gsi(NULL, interrupt, trigger, polarity); 233 } 234 235 static bool pcc_chan_plat_irq_can_be_shared(struct pcc_chan_info *pchan) 236 { 237 return (pchan->plat_irq_flags & ACPI_PCCT_INTERRUPT_MODE) == 238 ACPI_LEVEL_SENSITIVE; 239 } 240 241 static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan) 242 { 243 u64 val; 244 int ret; 245 246 if (!pchan->cmd_complete.gas) 247 return true; 248 249 ret = pcc_chan_reg_read(&pchan->cmd_complete, &val); 250 if (ret) 251 return false; 252 253 /* 254 * Judge if the channel respond the interrupt based on the value of 255 * command complete. 256 */ 257 val &= pchan->cmd_complete.status_mask; 258 259 /* 260 * If this is PCC slave subspace channel, and the command complete 261 * bit 0 indicates that Platform is sending a notification and OSPM 262 * needs to respond this interrupt to process this command. 263 */ 264 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 265 return !val; 266 267 return !!val; 268 } 269 270 static int pcc_mbox_error_check_and_clear(struct pcc_chan_info *pchan) 271 { 272 u64 val; 273 int ret; 274 275 ret = pcc_chan_reg_read(&pchan->error, &val); 276 if (ret) 277 return ret; 278 279 val &= pchan->error.status_mask; 280 if (val) { 281 val &= ~pchan->error.status_mask; 282 pcc_chan_reg_write(&pchan->error, val); 283 return -EIO; 284 } 285 286 return 0; 287 } 288 289 static void pcc_chan_acknowledge(struct pcc_chan_info *pchan) 290 { 291 struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_hdr; 292 293 if (pchan->type != ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 294 return; 295 296 pcc_chan_reg_read_modify_write(&pchan->cmd_update); 297 298 pcc_hdr = pchan->chan.shmem; 299 300 /* 301 * The PCC slave subspace channel needs to set the command 302 * complete bit after processing message. If the PCC_ACK_FLAG 303 * is set, it should also ring the doorbell. 304 */ 305 if (ioread32(&pcc_hdr->flags) & PCC_CMD_COMPLETION_NOTIFY) 306 pcc_chan_reg_read_modify_write(&pchan->db); 307 } 308 309 /** 310 * pcc_mbox_irq - PCC mailbox interrupt handler 311 * @irq: interrupt number 312 * @p: data/cookie passed from the caller to identify the channel 313 * 314 * Returns: IRQ_HANDLED if interrupt is handled or IRQ_NONE if not 315 */ 316 static irqreturn_t pcc_mbox_irq(int irq, void *p) 317 { 318 struct pcc_chan_info *pchan; 319 struct mbox_chan *chan = p; 320 321 pchan = chan->con_priv; 322 323 if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack)) 324 return IRQ_NONE; 325 326 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE && 327 !pchan->chan_in_use) 328 return IRQ_NONE; 329 330 if (!pcc_mbox_cmd_complete_check(pchan)) 331 return IRQ_NONE; 332 333 if (pcc_mbox_error_check_and_clear(pchan)) 334 return IRQ_NONE; 335 336 /* 337 * Clear this flag after updating interrupt ack register and just 338 * before mbox_chan_received_data() which might call pcc_send_data() 339 * where the flag is set again to start new transfer. This is 340 * required to avoid any possible race in updatation of this flag. 341 */ 342 pchan->chan_in_use = false; 343 mbox_chan_received_data(chan, NULL); 344 345 pcc_chan_acknowledge(pchan); 346 347 return IRQ_HANDLED; 348 } 349 350 /** 351 * pcc_mbox_request_channel - PCC clients call this function to 352 * request a pointer to their PCC subspace, from which they 353 * can get the details of communicating with the remote. 354 * @cl: Pointer to Mailbox client, so we know where to bind the 355 * Channel. 356 * @subspace_id: The PCC Subspace index as parsed in the PCC client 357 * ACPI package. This is used to lookup the array of PCC 358 * subspaces as parsed by the PCC Mailbox controller. 359 * 360 * Return: Pointer to the PCC Mailbox Channel if successful or ERR_PTR. 361 */ 362 struct pcc_mbox_chan * 363 pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id) 364 { 365 struct pcc_mbox_chan *pcc_mchan; 366 struct pcc_chan_info *pchan; 367 struct mbox_chan *chan; 368 int rc; 369 370 if (subspace_id < 0 || subspace_id >= pcc_chan_count) 371 return ERR_PTR(-ENOENT); 372 373 pchan = chan_info + subspace_id; 374 chan = pchan->chan.mchan; 375 if (IS_ERR(chan) || chan->cl) { 376 pr_err("Channel not found for idx: %d\n", subspace_id); 377 return ERR_PTR(-EBUSY); 378 } 379 380 rc = mbox_bind_client(chan, cl); 381 if (rc) 382 return ERR_PTR(rc); 383 384 pcc_mchan = &pchan->chan; 385 pcc_mchan->shmem = acpi_os_ioremap(pcc_mchan->shmem_base_addr, 386 pcc_mchan->shmem_size); 387 if (pcc_mchan->shmem) 388 return pcc_mchan; 389 390 mbox_free_channel(chan); 391 return ERR_PTR(-ENXIO); 392 } 393 EXPORT_SYMBOL_GPL(pcc_mbox_request_channel); 394 395 /** 396 * pcc_mbox_free_channel - Clients call this to free their Channel. 397 * 398 * @pchan: Pointer to the PCC mailbox channel as returned by 399 * pcc_mbox_request_channel() 400 */ 401 void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan) 402 { 403 struct mbox_chan *chan = pchan->mchan; 404 struct pcc_chan_info *pchan_info; 405 struct pcc_mbox_chan *pcc_mbox_chan; 406 407 if (!chan || !chan->cl) 408 return; 409 pchan_info = chan->con_priv; 410 pcc_mbox_chan = &pchan_info->chan; 411 if (pcc_mbox_chan->shmem) { 412 iounmap(pcc_mbox_chan->shmem); 413 pcc_mbox_chan->shmem = NULL; 414 } 415 416 mbox_free_channel(chan); 417 } 418 EXPORT_SYMBOL_GPL(pcc_mbox_free_channel); 419 420 /** 421 * pcc_send_data - Called from Mailbox Controller code. Used 422 * here only to ring the channel doorbell. The PCC client 423 * specific read/write is done in the client driver in 424 * order to maintain atomicity over PCC channel once 425 * OS has control over it. See above for flow of operations. 426 * @chan: Pointer to Mailbox channel over which to send data. 427 * @data: Client specific data written over channel. Used here 428 * only for debug after PCC transaction completes. 429 * 430 * Return: Err if something failed else 0 for success. 431 */ 432 static int pcc_send_data(struct mbox_chan *chan, void *data) 433 { 434 int ret; 435 struct pcc_chan_info *pchan = chan->con_priv; 436 437 ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update); 438 if (ret) 439 return ret; 440 441 ret = pcc_chan_reg_read_modify_write(&pchan->db); 442 if (!ret && pchan->plat_irq > 0) 443 pchan->chan_in_use = true; 444 445 return ret; 446 } 447 448 /** 449 * pcc_startup - Called from Mailbox Controller code. Used here 450 * to request the interrupt. 451 * @chan: Pointer to Mailbox channel to startup. 452 * 453 * Return: Err if something failed else 0 for success. 454 */ 455 static int pcc_startup(struct mbox_chan *chan) 456 { 457 struct pcc_chan_info *pchan = chan->con_priv; 458 unsigned long irqflags; 459 int rc; 460 461 if (pchan->plat_irq > 0) { 462 irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ? 463 IRQF_SHARED | IRQF_ONESHOT : 0; 464 rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq, 465 irqflags, MBOX_IRQ_NAME, chan); 466 if (unlikely(rc)) { 467 dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n", 468 pchan->plat_irq); 469 return rc; 470 } 471 } 472 473 return 0; 474 } 475 476 /** 477 * pcc_shutdown - Called from Mailbox Controller code. Used here 478 * to free the interrupt. 479 * @chan: Pointer to Mailbox channel to shutdown. 480 */ 481 static void pcc_shutdown(struct mbox_chan *chan) 482 { 483 struct pcc_chan_info *pchan = chan->con_priv; 484 485 if (pchan->plat_irq > 0) 486 devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan); 487 } 488 489 static const struct mbox_chan_ops pcc_chan_ops = { 490 .send_data = pcc_send_data, 491 .startup = pcc_startup, 492 .shutdown = pcc_shutdown, 493 }; 494 495 /** 496 * parse_pcc_subspace - Count PCC subspaces defined 497 * @header: Pointer to the ACPI subtable header under the PCCT. 498 * @end: End of subtable entry. 499 * 500 * Return: If we find a PCC subspace entry of a valid type, return 0. 501 * Otherwise, return -EINVAL. 502 * 503 * This gets called for each entry in the PCC table. 504 */ 505 static int parse_pcc_subspace(union acpi_subtable_headers *header, 506 const unsigned long end) 507 { 508 struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header; 509 510 if (ss->header.type < ACPI_PCCT_TYPE_RESERVED) 511 return 0; 512 513 return -EINVAL; 514 } 515 516 static int 517 pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas, 518 u64 preserve_mask, u64 set_mask, u64 status_mask, char *name) 519 { 520 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { 521 if (!(gas->bit_width >= 8 && gas->bit_width <= 64 && 522 is_power_of_2(gas->bit_width))) { 523 pr_err("Error: Cannot access register of %u bit width", 524 gas->bit_width); 525 return -EFAULT; 526 } 527 528 reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8); 529 if (!reg->vaddr) { 530 pr_err("Failed to ioremap PCC %s register\n", name); 531 return -ENOMEM; 532 } 533 } 534 reg->gas = gas; 535 reg->preserve_mask = preserve_mask; 536 reg->set_mask = set_mask; 537 reg->status_mask = status_mask; 538 return 0; 539 } 540 541 /** 542 * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register 543 * 544 * @pchan: Pointer to the PCC channel info structure. 545 * @pcct_entry: Pointer to the ACPI subtable header. 546 * 547 * Return: 0 for Success, else errno. 548 * 549 * There should be one entry per PCC channel. This gets called for each 550 * entry in the PCC table. This uses PCCY Type1 structure for all applicable 551 * types(Type 1-4) to fetch irq 552 */ 553 static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan, 554 struct acpi_subtable_header *pcct_entry) 555 { 556 int ret = 0; 557 struct acpi_pcct_hw_reduced *pcct_ss; 558 559 if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE || 560 pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 561 return 0; 562 563 pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry; 564 pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt, 565 (u32)pcct_ss->flags); 566 if (pchan->plat_irq <= 0) { 567 pr_err("PCC GSI %d not registered\n", 568 pcct_ss->platform_interrupt); 569 return -EINVAL; 570 } 571 pchan->plat_irq_flags = pcct_ss->flags; 572 573 if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 574 struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss; 575 576 ret = pcc_chan_reg_init(&pchan->plat_irq_ack, 577 &pcct2_ss->platform_ack_register, 578 pcct2_ss->ack_preserve_mask, 579 pcct2_ss->ack_write_mask, 0, 580 "PLAT IRQ ACK"); 581 582 } else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE || 583 pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) { 584 struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss; 585 586 ret = pcc_chan_reg_init(&pchan->plat_irq_ack, 587 &pcct_ext->platform_ack_register, 588 pcct_ext->ack_preserve_mask, 589 pcct_ext->ack_set_mask, 0, 590 "PLAT IRQ ACK"); 591 } 592 593 if (pcc_chan_plat_irq_can_be_shared(pchan) && 594 !pchan->plat_irq_ack.gas) { 595 pr_err("PCC subspace has level IRQ with no ACK register\n"); 596 return -EINVAL; 597 } 598 599 return ret; 600 } 601 602 /** 603 * pcc_parse_subspace_db_reg - Parse the PCC doorbell register 604 * 605 * @pchan: Pointer to the PCC channel info structure. 606 * @pcct_entry: Pointer to the ACPI subtable header. 607 * 608 * Return: 0 for Success, else errno. 609 */ 610 static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan, 611 struct acpi_subtable_header *pcct_entry) 612 { 613 int ret = 0; 614 615 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 616 struct acpi_pcct_subspace *pcct_ss; 617 618 pcct_ss = (struct acpi_pcct_subspace *)pcct_entry; 619 620 ret = pcc_chan_reg_init(&pchan->db, 621 &pcct_ss->doorbell_register, 622 pcct_ss->preserve_mask, 623 pcct_ss->write_mask, 0, "Doorbell"); 624 625 } else { 626 struct acpi_pcct_ext_pcc_master *pcct_ext; 627 628 pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry; 629 630 ret = pcc_chan_reg_init(&pchan->db, 631 &pcct_ext->doorbell_register, 632 pcct_ext->preserve_mask, 633 pcct_ext->write_mask, 0, "Doorbell"); 634 if (ret) 635 return ret; 636 637 ret = pcc_chan_reg_init(&pchan->cmd_complete, 638 &pcct_ext->cmd_complete_register, 639 0, 0, pcct_ext->cmd_complete_mask, 640 "Command Complete Check"); 641 if (ret) 642 return ret; 643 644 ret = pcc_chan_reg_init(&pchan->cmd_update, 645 &pcct_ext->cmd_update_register, 646 pcct_ext->cmd_update_preserve_mask, 647 pcct_ext->cmd_update_set_mask, 0, 648 "Command Complete Update"); 649 if (ret) 650 return ret; 651 652 ret = pcc_chan_reg_init(&pchan->error, 653 &pcct_ext->error_status_register, 654 0, 0, pcct_ext->error_status_mask, 655 "Error Status"); 656 } 657 return ret; 658 } 659 660 /** 661 * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information 662 * 663 * @pchan: Pointer to the PCC channel info structure. 664 * @pcct_entry: Pointer to the ACPI subtable header. 665 * 666 */ 667 static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan, 668 struct acpi_subtable_header *pcct_entry) 669 { 670 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 671 struct acpi_pcct_subspace *pcct_ss = 672 (struct acpi_pcct_subspace *)pcct_entry; 673 674 pchan->chan.shmem_base_addr = pcct_ss->base_address; 675 pchan->chan.shmem_size = pcct_ss->length; 676 pchan->chan.latency = pcct_ss->latency; 677 pchan->chan.max_access_rate = pcct_ss->max_access_rate; 678 pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time; 679 } else { 680 struct acpi_pcct_ext_pcc_master *pcct_ext = 681 (struct acpi_pcct_ext_pcc_master *)pcct_entry; 682 683 pchan->chan.shmem_base_addr = pcct_ext->base_address; 684 pchan->chan.shmem_size = pcct_ext->length; 685 pchan->chan.latency = pcct_ext->latency; 686 pchan->chan.max_access_rate = pcct_ext->max_access_rate; 687 pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time; 688 } 689 } 690 691 /** 692 * acpi_pcc_probe - Parse the ACPI tree for the PCCT. 693 * 694 * Return: 0 for Success, else errno. 695 */ 696 static int __init acpi_pcc_probe(void) 697 { 698 int count, i, rc = 0; 699 acpi_status status; 700 struct acpi_table_header *pcct_tbl; 701 struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED]; 702 703 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl); 704 if (ACPI_FAILURE(status) || !pcct_tbl) 705 return -ENODEV; 706 707 /* Set up the subtable handlers */ 708 for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE; 709 i < ACPI_PCCT_TYPE_RESERVED; i++) { 710 proc[i].id = i; 711 proc[i].count = 0; 712 proc[i].handler = parse_pcc_subspace; 713 } 714 715 count = acpi_table_parse_entries_array(ACPI_SIG_PCCT, 716 sizeof(struct acpi_table_pcct), proc, 717 ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES); 718 if (count <= 0 || count > MAX_PCC_SUBSPACES) { 719 if (count < 0) 720 pr_warn("Error parsing PCC subspaces from PCCT\n"); 721 else 722 pr_warn("Invalid PCCT: %d PCC subspaces\n", count); 723 724 rc = -EINVAL; 725 } else { 726 pcc_chan_count = count; 727 } 728 729 acpi_put_table(pcct_tbl); 730 731 return rc; 732 } 733 734 /** 735 * pcc_mbox_probe - Called when we find a match for the 736 * PCCT platform device. This is purely used to represent 737 * the PCCT as a virtual device for registering with the 738 * generic Mailbox framework. 739 * 740 * @pdev: Pointer to platform device returned when a match 741 * is found. 742 * 743 * Return: 0 for Success, else errno. 744 */ 745 static int pcc_mbox_probe(struct platform_device *pdev) 746 { 747 struct device *dev = &pdev->dev; 748 struct mbox_controller *pcc_mbox_ctrl; 749 struct mbox_chan *pcc_mbox_channels; 750 struct acpi_table_header *pcct_tbl; 751 struct acpi_subtable_header *pcct_entry; 752 struct acpi_table_pcct *acpi_pcct_tbl; 753 acpi_status status = AE_OK; 754 int i, rc, count = pcc_chan_count; 755 756 /* Search for PCCT */ 757 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl); 758 759 if (ACPI_FAILURE(status) || !pcct_tbl) 760 return -ENODEV; 761 762 pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels), 763 GFP_KERNEL); 764 if (!pcc_mbox_channels) { 765 rc = -ENOMEM; 766 goto err; 767 } 768 769 chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL); 770 if (!chan_info) { 771 rc = -ENOMEM; 772 goto err; 773 } 774 775 pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL); 776 if (!pcc_mbox_ctrl) { 777 rc = -ENOMEM; 778 goto err; 779 } 780 781 /* Point to the first PCC subspace entry */ 782 pcct_entry = (struct acpi_subtable_header *) ( 783 (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct)); 784 785 acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl; 786 if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL) 787 pcc_mbox_ctrl->txdone_irq = true; 788 789 for (i = 0; i < count; i++) { 790 struct pcc_chan_info *pchan = chan_info + i; 791 792 pcc_mbox_channels[i].con_priv = pchan; 793 pchan->chan.mchan = &pcc_mbox_channels[i]; 794 795 if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE && 796 !pcc_mbox_ctrl->txdone_irq) { 797 pr_err("Platform Interrupt flag must be set to 1"); 798 rc = -EINVAL; 799 goto err; 800 } 801 802 if (pcc_mbox_ctrl->txdone_irq) { 803 rc = pcc_parse_subspace_irq(pchan, pcct_entry); 804 if (rc < 0) 805 goto err; 806 } 807 rc = pcc_parse_subspace_db_reg(pchan, pcct_entry); 808 if (rc < 0) 809 goto err; 810 811 pcc_parse_subspace_shmem(pchan, pcct_entry); 812 813 pchan->type = pcct_entry->type; 814 pcct_entry = (struct acpi_subtable_header *) 815 ((unsigned long) pcct_entry + pcct_entry->length); 816 } 817 818 pcc_mbox_ctrl->num_chans = count; 819 820 pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl->num_chans); 821 822 pcc_mbox_ctrl->chans = pcc_mbox_channels; 823 pcc_mbox_ctrl->ops = &pcc_chan_ops; 824 pcc_mbox_ctrl->dev = dev; 825 826 pr_info("Registering PCC driver as Mailbox controller\n"); 827 rc = mbox_controller_register(pcc_mbox_ctrl); 828 if (rc) 829 pr_err("Err registering PCC as Mailbox controller: %d\n", rc); 830 else 831 return 0; 832 err: 833 acpi_put_table(pcct_tbl); 834 return rc; 835 } 836 837 static struct platform_driver pcc_mbox_driver = { 838 .probe = pcc_mbox_probe, 839 .driver = { 840 .name = "PCCT", 841 }, 842 }; 843 844 static int __init pcc_init(void) 845 { 846 int ret; 847 struct platform_device *pcc_pdev; 848 849 if (acpi_disabled) 850 return -ENODEV; 851 852 /* Check if PCC support is available. */ 853 ret = acpi_pcc_probe(); 854 855 if (ret) { 856 pr_debug("ACPI PCC probe failed.\n"); 857 return -ENODEV; 858 } 859 860 pcc_pdev = platform_create_bundle(&pcc_mbox_driver, 861 pcc_mbox_probe, NULL, 0, NULL, 0); 862 863 if (IS_ERR(pcc_pdev)) { 864 pr_debug("Err creating PCC platform bundle\n"); 865 pcc_chan_count = 0; 866 return PTR_ERR(pcc_pdev); 867 } 868 869 return 0; 870 } 871 872 /* 873 * Make PCC init postcore so that users of this mailbox 874 * such as the ACPI Processor driver have it available 875 * at their init. 876 */ 877 postcore_initcall(pcc_init); 878