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 static int pcc_send_data(struct mbox_chan *chan, void *data); 121 122 /* 123 * PCC can be used with perf critical drivers such as CPPC 124 * So it makes sense to locally cache the virtual address and 125 * use it to read/write to PCC registers such as doorbell register 126 * 127 * The below read_register and write_registers are used to read and 128 * write from perf critical registers such as PCC doorbell register 129 */ 130 static void read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width) 131 { 132 switch (bit_width) { 133 case 8: 134 *val = readb(vaddr); 135 break; 136 case 16: 137 *val = readw(vaddr); 138 break; 139 case 32: 140 *val = readl(vaddr); 141 break; 142 case 64: 143 *val = readq(vaddr); 144 break; 145 } 146 } 147 148 static void write_register(void __iomem *vaddr, u64 val, unsigned int bit_width) 149 { 150 switch (bit_width) { 151 case 8: 152 writeb(val, vaddr); 153 break; 154 case 16: 155 writew(val, vaddr); 156 break; 157 case 32: 158 writel(val, vaddr); 159 break; 160 case 64: 161 writeq(val, vaddr); 162 break; 163 } 164 } 165 166 static int pcc_chan_reg_read(struct pcc_chan_reg *reg, u64 *val) 167 { 168 int ret = 0; 169 170 if (!reg->gas) { 171 *val = 0; 172 return 0; 173 } 174 175 if (reg->vaddr) 176 read_register(reg->vaddr, val, reg->gas->bit_width); 177 else 178 ret = acpi_read(val, reg->gas); 179 180 return ret; 181 } 182 183 static int pcc_chan_reg_write(struct pcc_chan_reg *reg, u64 val) 184 { 185 int ret = 0; 186 187 if (!reg->gas) 188 return 0; 189 190 if (reg->vaddr) 191 write_register(reg->vaddr, val, reg->gas->bit_width); 192 else 193 ret = acpi_write(val, reg->gas); 194 195 return ret; 196 } 197 198 static int pcc_chan_reg_read_modify_write(struct pcc_chan_reg *reg) 199 { 200 int ret = 0; 201 u64 val; 202 203 ret = pcc_chan_reg_read(reg, &val); 204 if (ret) 205 return ret; 206 207 val &= reg->preserve_mask; 208 val |= reg->set_mask; 209 210 return pcc_chan_reg_write(reg, val); 211 } 212 213 /** 214 * pcc_map_interrupt - Map a PCC subspace GSI to a linux IRQ number 215 * @interrupt: GSI number. 216 * @flags: interrupt flags 217 * 218 * Returns: a valid linux IRQ number on success 219 * 0 or -EINVAL on failure 220 */ 221 static int pcc_map_interrupt(u32 interrupt, u32 flags) 222 { 223 int trigger, polarity; 224 225 if (!interrupt) 226 return 0; 227 228 trigger = (flags & ACPI_PCCT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE 229 : ACPI_LEVEL_SENSITIVE; 230 231 polarity = (flags & ACPI_PCCT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW 232 : ACPI_ACTIVE_HIGH; 233 234 return acpi_register_gsi(NULL, interrupt, trigger, polarity); 235 } 236 237 static bool pcc_chan_plat_irq_can_be_shared(struct pcc_chan_info *pchan) 238 { 239 return (pchan->plat_irq_flags & ACPI_PCCT_INTERRUPT_MODE) == 240 ACPI_LEVEL_SENSITIVE; 241 } 242 243 static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan) 244 { 245 u64 val; 246 int ret; 247 248 ret = pcc_chan_reg_read(&pchan->cmd_complete, &val); 249 if (ret) 250 return false; 251 252 if (!pchan->cmd_complete.gas) 253 return true; 254 255 /* 256 * Judge if the channel respond the interrupt based on the value of 257 * command complete. 258 */ 259 val &= pchan->cmd_complete.status_mask; 260 261 /* 262 * If this is PCC slave subspace channel, and the command complete 263 * bit 0 indicates that Platform is sending a notification and OSPM 264 * needs to respond this interrupt to process this command. 265 */ 266 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 267 return !val; 268 269 return !!val; 270 } 271 272 static void check_and_ack(struct pcc_chan_info *pchan, struct mbox_chan *chan) 273 { 274 struct acpi_pcct_ext_pcc_shared_memory pcc_hdr; 275 276 if (pchan->type != ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 277 return; 278 /* If the memory region has not been mapped, we cannot 279 * determine if we need to send the message, but we still 280 * need to set the cmd_update flag before returning. 281 */ 282 if (pchan->chan.shmem == NULL) { 283 pcc_chan_reg_read_modify_write(&pchan->cmd_update); 284 return; 285 } 286 memcpy_fromio(&pcc_hdr, pchan->chan.shmem, 287 sizeof(struct acpi_pcct_ext_pcc_shared_memory)); 288 /* 289 * The PCC slave subspace channel needs to set the command complete bit 290 * after processing message. If the PCC_ACK_FLAG is set, it should also 291 * ring the doorbell. 292 * 293 * The PCC master subspace channel clears chan_in_use to free channel. 294 */ 295 if (le32_to_cpup(&pcc_hdr.flags) & PCC_ACK_FLAG_MASK) 296 pcc_send_data(chan, NULL); 297 else 298 pcc_chan_reg_read_modify_write(&pchan->cmd_update); 299 } 300 301 /** 302 * pcc_mbox_irq - PCC mailbox interrupt handler 303 * @irq: interrupt number 304 * @p: data/cookie passed from the caller to identify the channel 305 * 306 * Returns: IRQ_HANDLED if interrupt is handled or IRQ_NONE if not 307 */ 308 static irqreturn_t pcc_mbox_irq(int irq, void *p) 309 { 310 struct pcc_chan_info *pchan; 311 struct mbox_chan *chan = p; 312 u64 val; 313 int ret; 314 315 pchan = chan->con_priv; 316 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE && 317 !pchan->chan_in_use) 318 return IRQ_NONE; 319 320 if (!pcc_mbox_cmd_complete_check(pchan)) 321 return IRQ_NONE; 322 323 ret = pcc_chan_reg_read(&pchan->error, &val); 324 if (ret) 325 return IRQ_NONE; 326 val &= pchan->error.status_mask; 327 if (val) { 328 val &= ~pchan->error.status_mask; 329 pcc_chan_reg_write(&pchan->error, val); 330 return IRQ_NONE; 331 } 332 333 if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack)) 334 return IRQ_NONE; 335 336 mbox_chan_received_data(chan, NULL); 337 338 check_and_ack(pchan, chan); 339 pchan->chan_in_use = false; 340 341 return IRQ_HANDLED; 342 } 343 344 /** 345 * pcc_mbox_request_channel - PCC clients call this function to 346 * request a pointer to their PCC subspace, from which they 347 * can get the details of communicating with the remote. 348 * @cl: Pointer to Mailbox client, so we know where to bind the 349 * Channel. 350 * @subspace_id: The PCC Subspace index as parsed in the PCC client 351 * ACPI package. This is used to lookup the array of PCC 352 * subspaces as parsed by the PCC Mailbox controller. 353 * 354 * Return: Pointer to the PCC Mailbox Channel if successful or ERR_PTR. 355 */ 356 struct pcc_mbox_chan * 357 pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id) 358 { 359 struct pcc_chan_info *pchan; 360 struct mbox_chan *chan; 361 int rc; 362 363 if (subspace_id < 0 || subspace_id >= pcc_chan_count) 364 return ERR_PTR(-ENOENT); 365 366 pchan = chan_info + subspace_id; 367 chan = pchan->chan.mchan; 368 if (IS_ERR(chan) || chan->cl) { 369 pr_err("Channel not found for idx: %d\n", subspace_id); 370 return ERR_PTR(-EBUSY); 371 } 372 373 rc = mbox_bind_client(chan, cl); 374 if (rc) 375 return ERR_PTR(rc); 376 377 return &pchan->chan; 378 } 379 EXPORT_SYMBOL_GPL(pcc_mbox_request_channel); 380 381 /** 382 * pcc_mbox_free_channel - Clients call this to free their Channel. 383 * 384 * @pchan: Pointer to the PCC mailbox channel as returned by 385 * pcc_mbox_request_channel() 386 */ 387 void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan) 388 { 389 struct mbox_chan *chan = pchan->mchan; 390 struct pcc_chan_info *pchan_info; 391 struct pcc_mbox_chan *pcc_mbox_chan; 392 393 if (!chan || !chan->cl) 394 return; 395 pchan_info = chan->con_priv; 396 pcc_mbox_chan = &pchan_info->chan; 397 if (pcc_mbox_chan->shmem) { 398 iounmap(pcc_mbox_chan->shmem); 399 pcc_mbox_chan->shmem = NULL; 400 } 401 402 mbox_free_channel(chan); 403 } 404 EXPORT_SYMBOL_GPL(pcc_mbox_free_channel); 405 406 int pcc_mbox_ioremap(struct mbox_chan *chan) 407 { 408 struct pcc_chan_info *pchan_info; 409 struct pcc_mbox_chan *pcc_mbox_chan; 410 411 if (!chan || !chan->cl) 412 return -1; 413 pchan_info = chan->con_priv; 414 pcc_mbox_chan = &pchan_info->chan; 415 pcc_mbox_chan->shmem = ioremap(pcc_mbox_chan->shmem_base_addr, 416 pcc_mbox_chan->shmem_size); 417 return 0; 418 } 419 EXPORT_SYMBOL_GPL(pcc_mbox_ioremap); 420 421 /** 422 * pcc_send_data - Called from Mailbox Controller code. Used 423 * here only to ring the channel doorbell. The PCC client 424 * specific read/write is done in the client driver in 425 * order to maintain atomicity over PCC channel once 426 * OS has control over it. See above for flow of operations. 427 * @chan: Pointer to Mailbox channel over which to send data. 428 * @data: Client specific data written over channel. Used here 429 * only for debug after PCC transaction completes. 430 * 431 * Return: Err if something failed else 0 for success. 432 */ 433 static int pcc_send_data(struct mbox_chan *chan, void *data) 434 { 435 int ret; 436 struct pcc_chan_info *pchan = chan->con_priv; 437 438 ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update); 439 if (ret) 440 return ret; 441 442 ret = pcc_chan_reg_read_modify_write(&pchan->db); 443 if (!ret && pchan->plat_irq > 0) 444 pchan->chan_in_use = true; 445 446 return ret; 447 } 448 449 /** 450 * pcc_startup - Called from Mailbox Controller code. Used here 451 * to request the interrupt. 452 * @chan: Pointer to Mailbox channel to startup. 453 * 454 * Return: Err if something failed else 0 for success. 455 */ 456 static int pcc_startup(struct mbox_chan *chan) 457 { 458 struct pcc_chan_info *pchan = chan->con_priv; 459 unsigned long irqflags; 460 int rc; 461 462 if (pchan->plat_irq > 0) { 463 irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ? 464 IRQF_SHARED | IRQF_ONESHOT : 0; 465 rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq, 466 irqflags, MBOX_IRQ_NAME, chan); 467 if (unlikely(rc)) { 468 dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n", 469 pchan->plat_irq); 470 return rc; 471 } 472 } 473 474 return 0; 475 } 476 477 /** 478 * pcc_shutdown - Called from Mailbox Controller code. Used here 479 * to free the interrupt. 480 * @chan: Pointer to Mailbox channel to shutdown. 481 */ 482 static void pcc_shutdown(struct mbox_chan *chan) 483 { 484 struct pcc_chan_info *pchan = chan->con_priv; 485 486 if (pchan->plat_irq > 0) 487 devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan); 488 } 489 490 static const struct mbox_chan_ops pcc_chan_ops = { 491 .send_data = pcc_send_data, 492 .startup = pcc_startup, 493 .shutdown = pcc_shutdown, 494 }; 495 496 /** 497 * parse_pcc_subspace - Count PCC subspaces defined 498 * @header: Pointer to the ACPI subtable header under the PCCT. 499 * @end: End of subtable entry. 500 * 501 * Return: If we find a PCC subspace entry of a valid type, return 0. 502 * Otherwise, return -EINVAL. 503 * 504 * This gets called for each entry in the PCC table. 505 */ 506 static int parse_pcc_subspace(union acpi_subtable_headers *header, 507 const unsigned long end) 508 { 509 struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header; 510 511 if (ss->header.type < ACPI_PCCT_TYPE_RESERVED) 512 return 0; 513 514 return -EINVAL; 515 } 516 517 static int 518 pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas, 519 u64 preserve_mask, u64 set_mask, u64 status_mask, char *name) 520 { 521 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { 522 if (!(gas->bit_width >= 8 && gas->bit_width <= 64 && 523 is_power_of_2(gas->bit_width))) { 524 pr_err("Error: Cannot access register of %u bit width", 525 gas->bit_width); 526 return -EFAULT; 527 } 528 529 reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8); 530 if (!reg->vaddr) { 531 pr_err("Failed to ioremap PCC %s register\n", name); 532 return -ENOMEM; 533 } 534 } 535 reg->gas = gas; 536 reg->preserve_mask = preserve_mask; 537 reg->set_mask = set_mask; 538 reg->status_mask = status_mask; 539 return 0; 540 } 541 542 /** 543 * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register 544 * 545 * @pchan: Pointer to the PCC channel info structure. 546 * @pcct_entry: Pointer to the ACPI subtable header. 547 * 548 * Return: 0 for Success, else errno. 549 * 550 * There should be one entry per PCC channel. This gets called for each 551 * entry in the PCC table. This uses PCCY Type1 structure for all applicable 552 * types(Type 1-4) to fetch irq 553 */ 554 static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan, 555 struct acpi_subtable_header *pcct_entry) 556 { 557 int ret = 0; 558 struct acpi_pcct_hw_reduced *pcct_ss; 559 560 if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE || 561 pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 562 return 0; 563 564 pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry; 565 pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt, 566 (u32)pcct_ss->flags); 567 if (pchan->plat_irq <= 0) { 568 pr_err("PCC GSI %d not registered\n", 569 pcct_ss->platform_interrupt); 570 return -EINVAL; 571 } 572 pchan->plat_irq_flags = pcct_ss->flags; 573 574 if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 575 struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss; 576 577 ret = pcc_chan_reg_init(&pchan->plat_irq_ack, 578 &pcct2_ss->platform_ack_register, 579 pcct2_ss->ack_preserve_mask, 580 pcct2_ss->ack_write_mask, 0, 581 "PLAT IRQ ACK"); 582 583 } else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE || 584 pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) { 585 struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss; 586 587 ret = pcc_chan_reg_init(&pchan->plat_irq_ack, 588 &pcct_ext->platform_ack_register, 589 pcct_ext->ack_preserve_mask, 590 pcct_ext->ack_set_mask, 0, 591 "PLAT IRQ ACK"); 592 } 593 594 if (pcc_chan_plat_irq_can_be_shared(pchan) && 595 !pchan->plat_irq_ack.gas) { 596 pr_err("PCC subspace has level IRQ with no ACK register\n"); 597 return -EINVAL; 598 } 599 600 return ret; 601 } 602 603 /** 604 * pcc_parse_subspace_db_reg - Parse the PCC doorbell register 605 * 606 * @pchan: Pointer to the PCC channel info structure. 607 * @pcct_entry: Pointer to the ACPI subtable header. 608 * 609 * Return: 0 for Success, else errno. 610 */ 611 static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan, 612 struct acpi_subtable_header *pcct_entry) 613 { 614 int ret = 0; 615 616 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 617 struct acpi_pcct_subspace *pcct_ss; 618 619 pcct_ss = (struct acpi_pcct_subspace *)pcct_entry; 620 621 ret = pcc_chan_reg_init(&pchan->db, 622 &pcct_ss->doorbell_register, 623 pcct_ss->preserve_mask, 624 pcct_ss->write_mask, 0, "Doorbell"); 625 626 } else { 627 struct acpi_pcct_ext_pcc_master *pcct_ext; 628 629 pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry; 630 631 ret = pcc_chan_reg_init(&pchan->db, 632 &pcct_ext->doorbell_register, 633 pcct_ext->preserve_mask, 634 pcct_ext->write_mask, 0, "Doorbell"); 635 if (ret) 636 return ret; 637 638 ret = pcc_chan_reg_init(&pchan->cmd_complete, 639 &pcct_ext->cmd_complete_register, 640 0, 0, pcct_ext->cmd_complete_mask, 641 "Command Complete Check"); 642 if (ret) 643 return ret; 644 645 ret = pcc_chan_reg_init(&pchan->cmd_update, 646 &pcct_ext->cmd_update_register, 647 pcct_ext->cmd_update_preserve_mask, 648 pcct_ext->cmd_update_set_mask, 0, 649 "Command Complete Update"); 650 if (ret) 651 return ret; 652 653 ret = pcc_chan_reg_init(&pchan->error, 654 &pcct_ext->error_status_register, 655 0, 0, pcct_ext->error_status_mask, 656 "Error Status"); 657 } 658 return ret; 659 } 660 661 /** 662 * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information 663 * 664 * @pchan: Pointer to the PCC channel info structure. 665 * @pcct_entry: Pointer to the ACPI subtable header. 666 * 667 */ 668 static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan, 669 struct acpi_subtable_header *pcct_entry) 670 { 671 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 672 struct acpi_pcct_subspace *pcct_ss = 673 (struct acpi_pcct_subspace *)pcct_entry; 674 675 pchan->chan.shmem_base_addr = pcct_ss->base_address; 676 pchan->chan.shmem_size = pcct_ss->length; 677 pchan->chan.latency = pcct_ss->latency; 678 pchan->chan.max_access_rate = pcct_ss->max_access_rate; 679 pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time; 680 } else { 681 struct acpi_pcct_ext_pcc_master *pcct_ext = 682 (struct acpi_pcct_ext_pcc_master *)pcct_entry; 683 684 pchan->chan.shmem_base_addr = pcct_ext->base_address; 685 pchan->chan.shmem_size = pcct_ext->length; 686 pchan->chan.latency = pcct_ext->latency; 687 pchan->chan.max_access_rate = pcct_ext->max_access_rate; 688 pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time; 689 } 690 } 691 692 /** 693 * acpi_pcc_probe - Parse the ACPI tree for the PCCT. 694 * 695 * Return: 0 for Success, else errno. 696 */ 697 static int __init acpi_pcc_probe(void) 698 { 699 int count, i, rc = 0; 700 acpi_status status; 701 struct acpi_table_header *pcct_tbl; 702 struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED]; 703 704 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl); 705 if (ACPI_FAILURE(status) || !pcct_tbl) 706 return -ENODEV; 707 708 /* Set up the subtable handlers */ 709 for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE; 710 i < ACPI_PCCT_TYPE_RESERVED; i++) { 711 proc[i].id = i; 712 proc[i].count = 0; 713 proc[i].handler = parse_pcc_subspace; 714 } 715 716 count = acpi_table_parse_entries_array(ACPI_SIG_PCCT, 717 sizeof(struct acpi_table_pcct), proc, 718 ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES); 719 if (count <= 0 || count > MAX_PCC_SUBSPACES) { 720 if (count < 0) 721 pr_warn("Error parsing PCC subspaces from PCCT\n"); 722 else 723 pr_warn("Invalid PCCT: %d PCC subspaces\n", count); 724 725 rc = -EINVAL; 726 } else { 727 pcc_chan_count = count; 728 } 729 730 acpi_put_table(pcct_tbl); 731 732 return rc; 733 } 734 735 /** 736 * pcc_mbox_probe - Called when we find a match for the 737 * PCCT platform device. This is purely used to represent 738 * the PCCT as a virtual device for registering with the 739 * generic Mailbox framework. 740 * 741 * @pdev: Pointer to platform device returned when a match 742 * is found. 743 * 744 * Return: 0 for Success, else errno. 745 */ 746 static int pcc_mbox_probe(struct platform_device *pdev) 747 { 748 struct device *dev = &pdev->dev; 749 struct mbox_controller *pcc_mbox_ctrl; 750 struct mbox_chan *pcc_mbox_channels; 751 struct acpi_table_header *pcct_tbl; 752 struct acpi_subtable_header *pcct_entry; 753 struct acpi_table_pcct *acpi_pcct_tbl; 754 acpi_status status = AE_OK; 755 int i, rc, count = pcc_chan_count; 756 757 /* Search for PCCT */ 758 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl); 759 760 if (ACPI_FAILURE(status) || !pcct_tbl) 761 return -ENODEV; 762 763 pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels), 764 GFP_KERNEL); 765 if (!pcc_mbox_channels) { 766 rc = -ENOMEM; 767 goto err; 768 } 769 770 chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL); 771 if (!chan_info) { 772 rc = -ENOMEM; 773 goto err; 774 } 775 776 pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL); 777 if (!pcc_mbox_ctrl) { 778 rc = -ENOMEM; 779 goto err; 780 } 781 782 /* Point to the first PCC subspace entry */ 783 pcct_entry = (struct acpi_subtable_header *) ( 784 (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct)); 785 786 acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl; 787 if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL) 788 pcc_mbox_ctrl->txdone_irq = true; 789 790 for (i = 0; i < count; i++) { 791 struct pcc_chan_info *pchan = chan_info + i; 792 793 pcc_mbox_channels[i].con_priv = pchan; 794 pchan->chan.mchan = &pcc_mbox_channels[i]; 795 796 if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE && 797 !pcc_mbox_ctrl->txdone_irq) { 798 pr_err("Platform Interrupt flag must be set to 1"); 799 rc = -EINVAL; 800 goto err; 801 } 802 803 if (pcc_mbox_ctrl->txdone_irq) { 804 rc = pcc_parse_subspace_irq(pchan, pcct_entry); 805 if (rc < 0) 806 goto err; 807 } 808 rc = pcc_parse_subspace_db_reg(pchan, pcct_entry); 809 if (rc < 0) 810 goto err; 811 812 pcc_parse_subspace_shmem(pchan, pcct_entry); 813 814 pchan->type = pcct_entry->type; 815 pcct_entry = (struct acpi_subtable_header *) 816 ((unsigned long) pcct_entry + pcct_entry->length); 817 } 818 819 pcc_mbox_ctrl->num_chans = count; 820 821 pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl->num_chans); 822 823 pcc_mbox_ctrl->chans = pcc_mbox_channels; 824 pcc_mbox_ctrl->ops = &pcc_chan_ops; 825 pcc_mbox_ctrl->dev = dev; 826 827 pr_info("Registering PCC driver as Mailbox controller\n"); 828 rc = mbox_controller_register(pcc_mbox_ctrl); 829 if (rc) 830 pr_err("Err registering PCC as Mailbox controller: %d\n", rc); 831 else 832 return 0; 833 err: 834 acpi_put_table(pcct_tbl); 835 return rc; 836 } 837 838 static struct platform_driver pcc_mbox_driver = { 839 .probe = pcc_mbox_probe, 840 .driver = { 841 .name = "PCCT", 842 }, 843 }; 844 845 static int __init pcc_init(void) 846 { 847 int ret; 848 struct platform_device *pcc_pdev; 849 850 if (acpi_disabled) 851 return -ENODEV; 852 853 /* Check if PCC support is available. */ 854 ret = acpi_pcc_probe(); 855 856 if (ret) { 857 pr_debug("ACPI PCC probe failed.\n"); 858 return -ENODEV; 859 } 860 861 pcc_pdev = platform_create_bundle(&pcc_mbox_driver, 862 pcc_mbox_probe, NULL, 0, NULL, 0); 863 864 if (IS_ERR(pcc_pdev)) { 865 pr_debug("Err creating PCC platform bundle\n"); 866 pcc_chan_count = 0; 867 return PTR_ERR(pcc_pdev); 868 } 869 870 return 0; 871 } 872 873 /* 874 * Make PCC init postcore so that users of this mailbox 875 * such as the ACPI Processor driver have it available 876 * at their init. 877 */ 878 postcore_initcall(pcc_init); 879