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 if (val & pchan->error.status_mask) { 280 val &= pchan->error.preserve_mask; 281 pcc_chan_reg_write(&pchan->error, val); 282 return -EIO; 283 } 284 285 return 0; 286 } 287 288 static void pcc_chan_acknowledge(struct pcc_chan_info *pchan) 289 { 290 struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_hdr; 291 292 if (pchan->type != ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 293 return; 294 295 pcc_chan_reg_read_modify_write(&pchan->cmd_update); 296 297 pcc_hdr = pchan->chan.shmem; 298 299 /* 300 * The PCC slave subspace channel needs to set the command 301 * complete bit after processing message. If the PCC_ACK_FLAG 302 * is set, it should also ring the doorbell. 303 */ 304 if (ioread32(&pcc_hdr->flags) & PCC_CMD_COMPLETION_NOTIFY) 305 pcc_chan_reg_read_modify_write(&pchan->db); 306 } 307 308 /** 309 * pcc_mbox_irq - PCC mailbox interrupt handler 310 * @irq: interrupt number 311 * @p: data/cookie passed from the caller to identify the channel 312 * 313 * Returns: IRQ_HANDLED if interrupt is handled or IRQ_NONE if not 314 */ 315 static irqreturn_t pcc_mbox_irq(int irq, void *p) 316 { 317 struct pcc_chan_info *pchan; 318 struct mbox_chan *chan = p; 319 320 pchan = chan->con_priv; 321 322 if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack)) 323 return IRQ_NONE; 324 325 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE && 326 !pchan->chan_in_use) 327 return IRQ_NONE; 328 329 if (!pcc_mbox_cmd_complete_check(pchan)) 330 return IRQ_NONE; 331 332 if (pcc_mbox_error_check_and_clear(pchan)) 333 return IRQ_NONE; 334 335 /* 336 * Clear this flag after updating interrupt ack register and just 337 * before mbox_chan_received_data() which might call pcc_send_data() 338 * where the flag is set again to start new transfer. This is 339 * required to avoid any possible race in updatation of this flag. 340 */ 341 pchan->chan_in_use = false; 342 mbox_chan_received_data(chan, NULL); 343 mbox_chan_txdone(chan, 0); 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 pcc_mchan = &pchan->chan; 381 pcc_mchan->shmem = acpi_os_ioremap(pcc_mchan->shmem_base_addr, 382 pcc_mchan->shmem_size); 383 if (!pcc_mchan->shmem) 384 return ERR_PTR(-ENXIO); 385 386 rc = mbox_bind_client(chan, cl); 387 if (rc) { 388 iounmap(pcc_mchan->shmem); 389 pcc_mchan->shmem = NULL; 390 return ERR_PTR(rc); 391 } 392 393 return pcc_mchan; 394 } 395 EXPORT_SYMBOL_GPL(pcc_mbox_request_channel); 396 397 /** 398 * pcc_mbox_free_channel - Clients call this to free their Channel. 399 * 400 * @pchan: Pointer to the PCC mailbox channel as returned by 401 * pcc_mbox_request_channel() 402 */ 403 void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan) 404 { 405 struct mbox_chan *chan = pchan->mchan; 406 struct pcc_chan_info *pchan_info; 407 struct pcc_mbox_chan *pcc_mbox_chan; 408 409 if (!chan || !chan->cl) 410 return; 411 pchan_info = chan->con_priv; 412 pcc_mbox_chan = &pchan_info->chan; 413 if (pcc_mbox_chan->shmem) { 414 iounmap(pcc_mbox_chan->shmem); 415 pcc_mbox_chan->shmem = NULL; 416 } 417 418 mbox_free_channel(chan); 419 } 420 EXPORT_SYMBOL_GPL(pcc_mbox_free_channel); 421 422 /** 423 * pcc_send_data - Called from Mailbox Controller code. Used 424 * here only to ring the channel doorbell. The PCC client 425 * specific read/write is done in the client driver in 426 * order to maintain atomicity over PCC channel once 427 * OS has control over it. See above for flow of operations. 428 * @chan: Pointer to Mailbox channel over which to send data. 429 * @data: Client specific data written over channel. Used here 430 * only for debug after PCC transaction completes. 431 * 432 * Return: Err if something failed else 0 for success. 433 */ 434 static int pcc_send_data(struct mbox_chan *chan, void *data) 435 { 436 int ret; 437 struct pcc_chan_info *pchan = chan->con_priv; 438 439 ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update); 440 if (ret) 441 return ret; 442 443 ret = pcc_chan_reg_read_modify_write(&pchan->db); 444 if (!ret && pchan->plat_irq > 0) 445 pchan->chan_in_use = true; 446 447 return ret; 448 } 449 450 static bool pcc_last_tx_done(struct mbox_chan *chan) 451 { 452 struct pcc_chan_info *pchan = chan->con_priv; 453 454 return pcc_mbox_cmd_complete_check(pchan); 455 } 456 457 /** 458 * pcc_startup - Called from Mailbox Controller code. Used here 459 * to request the interrupt. 460 * @chan: Pointer to Mailbox channel to startup. 461 * 462 * Return: Err if something failed else 0 for success. 463 */ 464 static int pcc_startup(struct mbox_chan *chan) 465 { 466 struct pcc_chan_info *pchan = chan->con_priv; 467 unsigned long irqflags; 468 int rc; 469 470 /* 471 * Clear and acknowledge any pending interrupts on responder channel 472 * before enabling the interrupt 473 */ 474 pcc_chan_acknowledge(pchan); 475 476 if (pchan->plat_irq > 0) { 477 irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ? 478 IRQF_SHARED : 0; 479 rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq, 480 irqflags, MBOX_IRQ_NAME, chan); 481 if (unlikely(rc)) { 482 dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n", 483 pchan->plat_irq); 484 return rc; 485 } 486 } 487 488 return 0; 489 } 490 491 /** 492 * pcc_shutdown - Called from Mailbox Controller code. Used here 493 * to free the interrupt. 494 * @chan: Pointer to Mailbox channel to shutdown. 495 */ 496 static void pcc_shutdown(struct mbox_chan *chan) 497 { 498 struct pcc_chan_info *pchan = chan->con_priv; 499 500 if (pchan->plat_irq > 0) 501 devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan); 502 } 503 504 static const struct mbox_chan_ops pcc_chan_ops = { 505 .send_data = pcc_send_data, 506 .startup = pcc_startup, 507 .shutdown = pcc_shutdown, 508 .last_tx_done = pcc_last_tx_done, 509 }; 510 511 /** 512 * parse_pcc_subspace - Count PCC subspaces defined 513 * @header: Pointer to the ACPI subtable header under the PCCT. 514 * @end: End of subtable entry. 515 * 516 * Return: If we find a PCC subspace entry of a valid type, return 0. 517 * Otherwise, return -EINVAL. 518 * 519 * This gets called for each entry in the PCC table. 520 */ 521 static int parse_pcc_subspace(union acpi_subtable_headers *header, 522 const unsigned long end) 523 { 524 struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header; 525 526 if (ss->header.type < ACPI_PCCT_TYPE_RESERVED) 527 return 0; 528 529 return -EINVAL; 530 } 531 532 static int 533 pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas, 534 u64 preserve_mask, u64 set_mask, u64 status_mask, char *name) 535 { 536 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { 537 if (!(gas->bit_width >= 8 && gas->bit_width <= 64 && 538 is_power_of_2(gas->bit_width))) { 539 pr_err("Error: Cannot access register of %u bit width", 540 gas->bit_width); 541 return -EFAULT; 542 } 543 544 reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8); 545 if (!reg->vaddr) { 546 pr_err("Failed to ioremap PCC %s register\n", name); 547 return -ENOMEM; 548 } 549 } 550 reg->gas = gas; 551 reg->preserve_mask = preserve_mask; 552 reg->set_mask = set_mask; 553 reg->status_mask = status_mask; 554 return 0; 555 } 556 557 /** 558 * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register 559 * 560 * @pchan: Pointer to the PCC channel info structure. 561 * @pcct_entry: Pointer to the ACPI subtable header. 562 * 563 * Return: 0 for Success, else errno. 564 * 565 * There should be one entry per PCC channel. This gets called for each 566 * entry in the PCC table. This uses PCCY Type1 structure for all applicable 567 * types(Type 1-4) to fetch irq 568 */ 569 static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan, 570 struct acpi_subtable_header *pcct_entry) 571 { 572 int ret = 0; 573 struct acpi_pcct_hw_reduced *pcct_ss; 574 575 if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE || 576 pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 577 return 0; 578 579 pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry; 580 pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt, 581 (u32)pcct_ss->flags); 582 if (pchan->plat_irq <= 0) { 583 pr_err("PCC GSI %d not registered\n", 584 pcct_ss->platform_interrupt); 585 return -EINVAL; 586 } 587 pchan->plat_irq_flags = pcct_ss->flags; 588 589 if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 590 struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss; 591 592 ret = pcc_chan_reg_init(&pchan->plat_irq_ack, 593 &pcct2_ss->platform_ack_register, 594 pcct2_ss->ack_preserve_mask, 595 pcct2_ss->ack_write_mask, 0, 596 "PLAT IRQ ACK"); 597 598 } else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE || 599 pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) { 600 struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss; 601 602 ret = pcc_chan_reg_init(&pchan->plat_irq_ack, 603 &pcct_ext->platform_ack_register, 604 pcct_ext->ack_preserve_mask, 605 pcct_ext->ack_set_mask, 0, 606 "PLAT IRQ ACK"); 607 } 608 609 if (pcc_chan_plat_irq_can_be_shared(pchan) && 610 !pchan->plat_irq_ack.gas) { 611 pr_err("PCC subspace has level IRQ with no ACK register\n"); 612 return -EINVAL; 613 } 614 615 return ret; 616 } 617 618 /** 619 * pcc_parse_subspace_db_reg - Parse the PCC doorbell register 620 * 621 * @pchan: Pointer to the PCC channel info structure. 622 * @pcct_entry: Pointer to the ACPI subtable header. 623 * 624 * Return: 0 for Success, else errno. 625 */ 626 static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan, 627 struct acpi_subtable_header *pcct_entry) 628 { 629 int ret = 0; 630 631 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 632 struct acpi_pcct_subspace *pcct_ss; 633 634 pcct_ss = (struct acpi_pcct_subspace *)pcct_entry; 635 636 ret = pcc_chan_reg_init(&pchan->db, 637 &pcct_ss->doorbell_register, 638 pcct_ss->preserve_mask, 639 pcct_ss->write_mask, 0, "Doorbell"); 640 641 } else { 642 struct acpi_pcct_ext_pcc_master *pcct_ext; 643 644 pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry; 645 646 ret = pcc_chan_reg_init(&pchan->db, 647 &pcct_ext->doorbell_register, 648 pcct_ext->preserve_mask, 649 pcct_ext->write_mask, 0, "Doorbell"); 650 if (ret) 651 return ret; 652 653 ret = pcc_chan_reg_init(&pchan->cmd_complete, 654 &pcct_ext->cmd_complete_register, 655 0, 0, pcct_ext->cmd_complete_mask, 656 "Command Complete Check"); 657 if (ret) 658 return ret; 659 660 ret = pcc_chan_reg_init(&pchan->cmd_update, 661 &pcct_ext->cmd_update_register, 662 pcct_ext->cmd_update_preserve_mask, 663 pcct_ext->cmd_update_set_mask, 0, 664 "Command Complete Update"); 665 if (ret) 666 return ret; 667 668 ret = pcc_chan_reg_init(&pchan->error, 669 &pcct_ext->error_status_register, 670 ~pcct_ext->error_status_mask, 0, 671 pcct_ext->error_status_mask, 672 "Error Status"); 673 } 674 return ret; 675 } 676 677 /** 678 * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information 679 * 680 * @pchan: Pointer to the PCC channel info structure. 681 * @pcct_entry: Pointer to the ACPI subtable header. 682 * 683 */ 684 static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan, 685 struct acpi_subtable_header *pcct_entry) 686 { 687 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 688 struct acpi_pcct_subspace *pcct_ss = 689 (struct acpi_pcct_subspace *)pcct_entry; 690 691 pchan->chan.shmem_base_addr = pcct_ss->base_address; 692 pchan->chan.shmem_size = pcct_ss->length; 693 pchan->chan.latency = pcct_ss->latency; 694 pchan->chan.max_access_rate = pcct_ss->max_access_rate; 695 pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time; 696 } else { 697 struct acpi_pcct_ext_pcc_master *pcct_ext = 698 (struct acpi_pcct_ext_pcc_master *)pcct_entry; 699 700 pchan->chan.shmem_base_addr = pcct_ext->base_address; 701 pchan->chan.shmem_size = pcct_ext->length; 702 pchan->chan.latency = pcct_ext->latency; 703 pchan->chan.max_access_rate = pcct_ext->max_access_rate; 704 pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time; 705 } 706 } 707 708 /** 709 * acpi_pcc_probe - Parse the ACPI tree for the PCCT. 710 * 711 * Return: 0 for Success, else errno. 712 */ 713 static int __init acpi_pcc_probe(void) 714 { 715 int count, i, rc = 0; 716 acpi_status status; 717 struct acpi_table_header *pcct_tbl; 718 struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED]; 719 720 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl); 721 if (ACPI_FAILURE(status) || !pcct_tbl) 722 return -ENODEV; 723 724 /* Set up the subtable handlers */ 725 for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE; 726 i < ACPI_PCCT_TYPE_RESERVED; i++) { 727 proc[i].id = i; 728 proc[i].count = 0; 729 proc[i].handler = parse_pcc_subspace; 730 } 731 732 count = acpi_table_parse_entries_array(ACPI_SIG_PCCT, 733 sizeof(struct acpi_table_pcct), proc, 734 ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES); 735 if (count <= 0 || count > MAX_PCC_SUBSPACES) { 736 if (count < 0) 737 pr_warn("Error parsing PCC subspaces from PCCT\n"); 738 else 739 pr_warn("Invalid PCCT: %d PCC subspaces\n", count); 740 741 rc = -EINVAL; 742 } else { 743 pcc_chan_count = count; 744 } 745 746 acpi_put_table(pcct_tbl); 747 748 return rc; 749 } 750 751 /** 752 * pcc_mbox_probe - Called when we find a match for the 753 * PCCT platform device. This is purely used to represent 754 * the PCCT as a virtual device for registering with the 755 * generic Mailbox framework. 756 * 757 * @pdev: Pointer to platform device returned when a match 758 * is found. 759 * 760 * Return: 0 for Success, else errno. 761 */ 762 static int pcc_mbox_probe(struct platform_device *pdev) 763 { 764 struct device *dev = &pdev->dev; 765 struct mbox_controller *pcc_mbox_ctrl; 766 struct mbox_chan *pcc_mbox_channels; 767 struct acpi_table_header *pcct_tbl; 768 struct acpi_subtable_header *pcct_entry; 769 struct acpi_table_pcct *acpi_pcct_tbl; 770 acpi_status status = AE_OK; 771 int i, rc, count = pcc_chan_count; 772 773 /* Search for PCCT */ 774 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl); 775 776 if (ACPI_FAILURE(status) || !pcct_tbl) 777 return -ENODEV; 778 779 pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels), 780 GFP_KERNEL); 781 if (!pcc_mbox_channels) { 782 rc = -ENOMEM; 783 goto err; 784 } 785 786 chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL); 787 if (!chan_info) { 788 rc = -ENOMEM; 789 goto err; 790 } 791 792 pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL); 793 if (!pcc_mbox_ctrl) { 794 rc = -ENOMEM; 795 goto err; 796 } 797 798 /* Point to the first PCC subspace entry */ 799 pcct_entry = (struct acpi_subtable_header *) ( 800 (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct)); 801 802 acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl; 803 if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL) { 804 pcc_mbox_ctrl->txdone_irq = true; 805 pcc_mbox_ctrl->txdone_poll = false; 806 } else { 807 pcc_mbox_ctrl->txdone_irq = false; 808 pcc_mbox_ctrl->txdone_poll = true; 809 } 810 811 for (i = 0; i < count; i++) { 812 struct pcc_chan_info *pchan = chan_info + i; 813 814 pcc_mbox_channels[i].con_priv = pchan; 815 pchan->chan.mchan = &pcc_mbox_channels[i]; 816 817 if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE && 818 !pcc_mbox_ctrl->txdone_irq) { 819 pr_err("Platform Interrupt flag must be set to 1"); 820 rc = -EINVAL; 821 goto err; 822 } 823 824 if (pcc_mbox_ctrl->txdone_irq) { 825 rc = pcc_parse_subspace_irq(pchan, pcct_entry); 826 if (rc < 0) 827 goto err; 828 } 829 rc = pcc_parse_subspace_db_reg(pchan, pcct_entry); 830 if (rc < 0) 831 goto err; 832 833 pcc_parse_subspace_shmem(pchan, pcct_entry); 834 835 pchan->type = pcct_entry->type; 836 pcct_entry = (struct acpi_subtable_header *) 837 ((unsigned long) pcct_entry + pcct_entry->length); 838 } 839 840 pcc_mbox_ctrl->num_chans = count; 841 842 pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl->num_chans); 843 844 pcc_mbox_ctrl->chans = pcc_mbox_channels; 845 pcc_mbox_ctrl->ops = &pcc_chan_ops; 846 pcc_mbox_ctrl->dev = dev; 847 848 pr_info("Registering PCC driver as Mailbox controller\n"); 849 rc = mbox_controller_register(pcc_mbox_ctrl); 850 if (rc) 851 pr_err("Err registering PCC as Mailbox controller: %d\n", rc); 852 else 853 return 0; 854 err: 855 acpi_put_table(pcct_tbl); 856 return rc; 857 } 858 859 static struct platform_driver pcc_mbox_driver = { 860 .probe = pcc_mbox_probe, 861 .driver = { 862 .name = "PCCT", 863 }, 864 }; 865 866 static int __init pcc_init(void) 867 { 868 int ret; 869 struct platform_device *pcc_pdev; 870 871 if (acpi_disabled) 872 return -ENODEV; 873 874 /* Check if PCC support is available. */ 875 ret = acpi_pcc_probe(); 876 877 if (ret) { 878 pr_debug("ACPI PCC probe failed.\n"); 879 return -ENODEV; 880 } 881 882 pcc_pdev = platform_create_bundle(&pcc_mbox_driver, 883 pcc_mbox_probe, NULL, 0, NULL, 0); 884 885 if (IS_ERR(pcc_pdev)) { 886 pr_debug("Err creating PCC platform bundle\n"); 887 pcc_chan_count = 0; 888 return PTR_ERR(pcc_pdev); 889 } 890 891 return 0; 892 } 893 894 /* 895 * Make PCC init postcore so that users of this mailbox 896 * such as the ACPI Processor driver have it available 897 * at their init. 898 */ 899 postcore_initcall(pcc_init); 900