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 static void *write_response(struct pcc_chan_info *pchan) 310 { 311 struct pcc_header pcc_header; 312 void *buffer; 313 int data_len; 314 315 memcpy_fromio(&pcc_header, pchan->chan.shmem, 316 sizeof(pcc_header)); 317 data_len = pcc_header.length - sizeof(u32) + sizeof(struct pcc_header); 318 319 buffer = pchan->chan.rx_alloc(pchan->chan.mchan->cl, data_len); 320 if (buffer != NULL) 321 memcpy_fromio(buffer, pchan->chan.shmem, data_len); 322 return buffer; 323 } 324 325 /** 326 * pcc_mbox_irq - PCC mailbox interrupt handler 327 * @irq: interrupt number 328 * @p: data/cookie passed from the caller to identify the channel 329 * 330 * Returns: IRQ_HANDLED if interrupt is handled or IRQ_NONE if not 331 */ 332 static irqreturn_t pcc_mbox_irq(int irq, void *p) 333 { 334 struct pcc_chan_info *pchan; 335 struct mbox_chan *chan = p; 336 struct pcc_header *pcc_header = chan->active_req; 337 void *handle = NULL; 338 339 pchan = chan->con_priv; 340 341 if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack)) 342 return IRQ_NONE; 343 344 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE && 345 !pchan->chan_in_use) 346 return IRQ_NONE; 347 348 if (!pcc_mbox_cmd_complete_check(pchan)) 349 return IRQ_NONE; 350 351 if (pcc_mbox_error_check_and_clear(pchan)) 352 return IRQ_NONE; 353 354 /* 355 * Clear this flag after updating interrupt ack register and just 356 * before mbox_chan_received_data() which might call pcc_send_data() 357 * where the flag is set again to start new transfer. This is 358 * required to avoid any possible race in updatation of this flag. 359 */ 360 pchan->chan_in_use = false; 361 362 if (pchan->chan.rx_alloc) 363 handle = write_response(pchan); 364 365 if (chan->active_req) { 366 pcc_header = chan->active_req; 367 if (pcc_header->flags & PCC_CMD_COMPLETION_NOTIFY) 368 mbox_chan_txdone(chan, 0); 369 } 370 371 mbox_chan_received_data(chan, handle); 372 373 pcc_chan_acknowledge(pchan); 374 375 return IRQ_HANDLED; 376 } 377 378 /** 379 * pcc_mbox_request_channel - PCC clients call this function to 380 * request a pointer to their PCC subspace, from which they 381 * can get the details of communicating with the remote. 382 * @cl: Pointer to Mailbox client, so we know where to bind the 383 * Channel. 384 * @subspace_id: The PCC Subspace index as parsed in the PCC client 385 * ACPI package. This is used to lookup the array of PCC 386 * subspaces as parsed by the PCC Mailbox controller. 387 * 388 * Return: Pointer to the PCC Mailbox Channel if successful or ERR_PTR. 389 */ 390 struct pcc_mbox_chan * 391 pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id) 392 { 393 struct pcc_mbox_chan *pcc_mchan; 394 struct pcc_chan_info *pchan; 395 struct mbox_chan *chan; 396 int rc; 397 398 if (subspace_id < 0 || subspace_id >= pcc_chan_count) 399 return ERR_PTR(-ENOENT); 400 401 pchan = chan_info + subspace_id; 402 chan = pchan->chan.mchan; 403 if (IS_ERR(chan) || chan->cl) { 404 pr_err("Channel not found for idx: %d\n", subspace_id); 405 return ERR_PTR(-EBUSY); 406 } 407 408 rc = mbox_bind_client(chan, cl); 409 if (rc) 410 return ERR_PTR(rc); 411 412 pcc_mchan = &pchan->chan; 413 pcc_mchan->shmem = acpi_os_ioremap(pcc_mchan->shmem_base_addr, 414 pcc_mchan->shmem_size); 415 if (!pcc_mchan->shmem) 416 goto err; 417 418 pcc_mchan->manage_writes = false; 419 420 /* This indicates that the channel is ready to accept messages. 421 * This needs to happen after the channel has registered 422 * its callback. There is no access point to do that in 423 * the mailbox API. That implies that the mailbox client must 424 * have set the allocate callback function prior to 425 * sending any messages. 426 */ 427 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 428 pcc_chan_reg_read_modify_write(&pchan->cmd_update); 429 430 return pcc_mchan; 431 432 err: 433 mbox_free_channel(chan); 434 return ERR_PTR(-ENXIO); 435 } 436 EXPORT_SYMBOL_GPL(pcc_mbox_request_channel); 437 438 /** 439 * pcc_mbox_free_channel - Clients call this to free their Channel. 440 * 441 * @pchan: Pointer to the PCC mailbox channel as returned by 442 * pcc_mbox_request_channel() 443 */ 444 void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan) 445 { 446 struct mbox_chan *chan = pchan->mchan; 447 struct pcc_chan_info *pchan_info; 448 struct pcc_mbox_chan *pcc_mbox_chan; 449 450 if (!chan || !chan->cl) 451 return; 452 pchan_info = chan->con_priv; 453 pcc_mbox_chan = &pchan_info->chan; 454 if (pcc_mbox_chan->shmem) { 455 iounmap(pcc_mbox_chan->shmem); 456 pcc_mbox_chan->shmem = NULL; 457 } 458 459 mbox_free_channel(chan); 460 } 461 EXPORT_SYMBOL_GPL(pcc_mbox_free_channel); 462 463 static int pcc_write_to_buffer(struct mbox_chan *chan, void *data) 464 { 465 struct pcc_chan_info *pchan = chan->con_priv; 466 struct pcc_mbox_chan *pcc_mbox_chan = &pchan->chan; 467 struct pcc_header *pcc_header = data; 468 469 if (!pchan->chan.manage_writes) 470 return 0; 471 472 /* The PCC header length includes the command field 473 * but not the other values from the header. 474 */ 475 int len = pcc_header->length - sizeof(u32) + sizeof(struct pcc_header); 476 u64 val; 477 478 pcc_chan_reg_read(&pchan->cmd_complete, &val); 479 if (!val) { 480 pr_info("%s pchan->cmd_complete not set", __func__); 481 return -1; 482 } 483 memcpy_toio(pcc_mbox_chan->shmem, data, len); 484 return 0; 485 } 486 487 488 /** 489 * pcc_send_data - Called from Mailbox Controller code. If 490 * pchan->chan.rx_alloc is set, then the command complete 491 * flag is checked and the data is written to the shared 492 * buffer io memory. 493 * 494 * If pchan->chan.rx_alloc is not set, then it is used 495 * here only to ring the channel doorbell. The PCC client 496 * specific read/write is done in the client driver in 497 * order to maintain atomicity over PCC channel once 498 * OS has control over it. See above for flow of operations. 499 * @chan: Pointer to Mailbox channel over which to send data. 500 * @data: Client specific data written over channel. Used here 501 * only for debug after PCC transaction completes. 502 * 503 * Return: Err if something failed else 0 for success. 504 */ 505 static int pcc_send_data(struct mbox_chan *chan, void *data) 506 { 507 int ret; 508 struct pcc_chan_info *pchan = chan->con_priv; 509 510 ret = pcc_write_to_buffer(chan, data); 511 if (ret) 512 return ret; 513 514 ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update); 515 if (ret) 516 return ret; 517 518 ret = pcc_chan_reg_read_modify_write(&pchan->db); 519 520 if (!ret && pchan->plat_irq > 0) 521 pchan->chan_in_use = true; 522 523 return ret; 524 } 525 526 527 static bool pcc_last_tx_done(struct mbox_chan *chan) 528 { 529 struct pcc_chan_info *pchan = chan->con_priv; 530 u64 val; 531 532 pcc_chan_reg_read(&pchan->cmd_complete, &val); 533 if (!val) 534 return false; 535 else 536 return true; 537 } 538 539 540 541 /** 542 * pcc_startup - Called from Mailbox Controller code. Used here 543 * to request the interrupt. 544 * @chan: Pointer to Mailbox channel to startup. 545 * 546 * Return: Err if something failed else 0 for success. 547 */ 548 static int pcc_startup(struct mbox_chan *chan) 549 { 550 struct pcc_chan_info *pchan = chan->con_priv; 551 unsigned long irqflags; 552 int rc; 553 554 if (pchan->plat_irq > 0) { 555 irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ? 556 IRQF_SHARED | IRQF_ONESHOT : 0; 557 rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq, 558 irqflags, MBOX_IRQ_NAME, chan); 559 if (unlikely(rc)) { 560 dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n", 561 pchan->plat_irq); 562 return rc; 563 } 564 } 565 566 return 0; 567 } 568 569 /** 570 * pcc_shutdown - Called from Mailbox Controller code. Used here 571 * to free the interrupt. 572 * @chan: Pointer to Mailbox channel to shutdown. 573 */ 574 static void pcc_shutdown(struct mbox_chan *chan) 575 { 576 struct pcc_chan_info *pchan = chan->con_priv; 577 578 if (pchan->plat_irq > 0) 579 devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan); 580 } 581 582 static const struct mbox_chan_ops pcc_chan_ops = { 583 .send_data = pcc_send_data, 584 .startup = pcc_startup, 585 .shutdown = pcc_shutdown, 586 .last_tx_done = pcc_last_tx_done, 587 }; 588 589 /** 590 * parse_pcc_subspace - Count PCC subspaces defined 591 * @header: Pointer to the ACPI subtable header under the PCCT. 592 * @end: End of subtable entry. 593 * 594 * Return: If we find a PCC subspace entry of a valid type, return 0. 595 * Otherwise, return -EINVAL. 596 * 597 * This gets called for each entry in the PCC table. 598 */ 599 static int parse_pcc_subspace(union acpi_subtable_headers *header, 600 const unsigned long end) 601 { 602 struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header; 603 604 if (ss->header.type < ACPI_PCCT_TYPE_RESERVED) 605 return 0; 606 607 return -EINVAL; 608 } 609 610 static int 611 pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas, 612 u64 preserve_mask, u64 set_mask, u64 status_mask, char *name) 613 { 614 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { 615 if (!(gas->bit_width >= 8 && gas->bit_width <= 64 && 616 is_power_of_2(gas->bit_width))) { 617 pr_err("Error: Cannot access register of %u bit width", 618 gas->bit_width); 619 return -EFAULT; 620 } 621 622 reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8); 623 if (!reg->vaddr) { 624 pr_err("Failed to ioremap PCC %s register\n", name); 625 return -ENOMEM; 626 } 627 } 628 reg->gas = gas; 629 reg->preserve_mask = preserve_mask; 630 reg->set_mask = set_mask; 631 reg->status_mask = status_mask; 632 return 0; 633 } 634 635 /** 636 * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register 637 * 638 * @pchan: Pointer to the PCC channel info structure. 639 * @pcct_entry: Pointer to the ACPI subtable header. 640 * 641 * Return: 0 for Success, else errno. 642 * 643 * There should be one entry per PCC channel. This gets called for each 644 * entry in the PCC table. This uses PCCY Type1 structure for all applicable 645 * types(Type 1-4) to fetch irq 646 */ 647 static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan, 648 struct acpi_subtable_header *pcct_entry) 649 { 650 int ret = 0; 651 struct acpi_pcct_hw_reduced *pcct_ss; 652 653 if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE || 654 pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) 655 return 0; 656 657 pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry; 658 pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt, 659 (u32)pcct_ss->flags); 660 if (pchan->plat_irq <= 0) { 661 pr_err("PCC GSI %d not registered\n", 662 pcct_ss->platform_interrupt); 663 return -EINVAL; 664 } 665 pchan->plat_irq_flags = pcct_ss->flags; 666 667 if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 668 struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss; 669 670 ret = pcc_chan_reg_init(&pchan->plat_irq_ack, 671 &pcct2_ss->platform_ack_register, 672 pcct2_ss->ack_preserve_mask, 673 pcct2_ss->ack_write_mask, 0, 674 "PLAT IRQ ACK"); 675 676 } else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE || 677 pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) { 678 struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss; 679 680 ret = pcc_chan_reg_init(&pchan->plat_irq_ack, 681 &pcct_ext->platform_ack_register, 682 pcct_ext->ack_preserve_mask, 683 pcct_ext->ack_set_mask, 0, 684 "PLAT IRQ ACK"); 685 } 686 687 if (pcc_chan_plat_irq_can_be_shared(pchan) && 688 !pchan->plat_irq_ack.gas) { 689 pr_err("PCC subspace has level IRQ with no ACK register\n"); 690 return -EINVAL; 691 } 692 693 return ret; 694 } 695 696 /** 697 * pcc_parse_subspace_db_reg - Parse the PCC doorbell register 698 * 699 * @pchan: Pointer to the PCC channel info structure. 700 * @pcct_entry: Pointer to the ACPI subtable header. 701 * 702 * Return: 0 for Success, else errno. 703 */ 704 static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan, 705 struct acpi_subtable_header *pcct_entry) 706 { 707 int ret = 0; 708 709 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 710 struct acpi_pcct_subspace *pcct_ss; 711 712 pcct_ss = (struct acpi_pcct_subspace *)pcct_entry; 713 714 ret = pcc_chan_reg_init(&pchan->db, 715 &pcct_ss->doorbell_register, 716 pcct_ss->preserve_mask, 717 pcct_ss->write_mask, 0, "Doorbell"); 718 719 } else { 720 struct acpi_pcct_ext_pcc_master *pcct_ext; 721 722 pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry; 723 724 ret = pcc_chan_reg_init(&pchan->db, 725 &pcct_ext->doorbell_register, 726 pcct_ext->preserve_mask, 727 pcct_ext->write_mask, 0, "Doorbell"); 728 if (ret) 729 return ret; 730 731 ret = pcc_chan_reg_init(&pchan->cmd_complete, 732 &pcct_ext->cmd_complete_register, 733 0, 0, pcct_ext->cmd_complete_mask, 734 "Command Complete Check"); 735 if (ret) 736 return ret; 737 738 ret = pcc_chan_reg_init(&pchan->cmd_update, 739 &pcct_ext->cmd_update_register, 740 pcct_ext->cmd_update_preserve_mask, 741 pcct_ext->cmd_update_set_mask, 0, 742 "Command Complete Update"); 743 if (ret) 744 return ret; 745 746 ret = pcc_chan_reg_init(&pchan->error, 747 &pcct_ext->error_status_register, 748 0, 0, pcct_ext->error_status_mask, 749 "Error Status"); 750 } 751 return ret; 752 } 753 754 /** 755 * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information 756 * 757 * @pchan: Pointer to the PCC channel info structure. 758 * @pcct_entry: Pointer to the ACPI subtable header. 759 * 760 */ 761 static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan, 762 struct acpi_subtable_header *pcct_entry) 763 { 764 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) { 765 struct acpi_pcct_subspace *pcct_ss = 766 (struct acpi_pcct_subspace *)pcct_entry; 767 768 pchan->chan.shmem_base_addr = pcct_ss->base_address; 769 pchan->chan.shmem_size = pcct_ss->length; 770 pchan->chan.latency = pcct_ss->latency; 771 pchan->chan.max_access_rate = pcct_ss->max_access_rate; 772 pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time; 773 } else { 774 struct acpi_pcct_ext_pcc_master *pcct_ext = 775 (struct acpi_pcct_ext_pcc_master *)pcct_entry; 776 777 pchan->chan.shmem_base_addr = pcct_ext->base_address; 778 pchan->chan.shmem_size = pcct_ext->length; 779 pchan->chan.latency = pcct_ext->latency; 780 pchan->chan.max_access_rate = pcct_ext->max_access_rate; 781 pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time; 782 } 783 } 784 785 /** 786 * acpi_pcc_probe - Parse the ACPI tree for the PCCT. 787 * 788 * Return: 0 for Success, else errno. 789 */ 790 static int __init acpi_pcc_probe(void) 791 { 792 int count, i, rc = 0; 793 acpi_status status; 794 struct acpi_table_header *pcct_tbl; 795 struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED]; 796 797 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl); 798 if (ACPI_FAILURE(status) || !pcct_tbl) 799 return -ENODEV; 800 801 /* Set up the subtable handlers */ 802 for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE; 803 i < ACPI_PCCT_TYPE_RESERVED; i++) { 804 proc[i].id = i; 805 proc[i].count = 0; 806 proc[i].handler = parse_pcc_subspace; 807 } 808 809 count = acpi_table_parse_entries_array(ACPI_SIG_PCCT, 810 sizeof(struct acpi_table_pcct), proc, 811 ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES); 812 if (count <= 0 || count > MAX_PCC_SUBSPACES) { 813 if (count < 0) 814 pr_warn("Error parsing PCC subspaces from PCCT\n"); 815 else 816 pr_warn("Invalid PCCT: %d PCC subspaces\n", count); 817 818 rc = -EINVAL; 819 } else { 820 pcc_chan_count = count; 821 } 822 823 acpi_put_table(pcct_tbl); 824 825 return rc; 826 } 827 828 /** 829 * pcc_mbox_probe - Called when we find a match for the 830 * PCCT platform device. This is purely used to represent 831 * the PCCT as a virtual device for registering with the 832 * generic Mailbox framework. 833 * 834 * @pdev: Pointer to platform device returned when a match 835 * is found. 836 * 837 * Return: 0 for Success, else errno. 838 */ 839 static int pcc_mbox_probe(struct platform_device *pdev) 840 { 841 struct device *dev = &pdev->dev; 842 struct mbox_controller *pcc_mbox_ctrl; 843 struct mbox_chan *pcc_mbox_channels; 844 struct acpi_table_header *pcct_tbl; 845 struct acpi_subtable_header *pcct_entry; 846 struct acpi_table_pcct *acpi_pcct_tbl; 847 acpi_status status = AE_OK; 848 int i, rc, count = pcc_chan_count; 849 850 /* Search for PCCT */ 851 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl); 852 853 if (ACPI_FAILURE(status) || !pcct_tbl) 854 return -ENODEV; 855 856 pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels), 857 GFP_KERNEL); 858 if (!pcc_mbox_channels) { 859 rc = -ENOMEM; 860 goto err; 861 } 862 863 chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL); 864 if (!chan_info) { 865 rc = -ENOMEM; 866 goto err; 867 } 868 869 pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL); 870 if (!pcc_mbox_ctrl) { 871 rc = -ENOMEM; 872 goto err; 873 } 874 875 /* Point to the first PCC subspace entry */ 876 pcct_entry = (struct acpi_subtable_header *) ( 877 (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct)); 878 879 acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl; 880 if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL) 881 pcc_mbox_ctrl->txdone_irq = true; 882 883 for (i = 0; i < count; i++) { 884 struct pcc_chan_info *pchan = chan_info + i; 885 886 pcc_mbox_channels[i].con_priv = pchan; 887 pchan->chan.mchan = &pcc_mbox_channels[i]; 888 889 if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE && 890 !pcc_mbox_ctrl->txdone_irq) { 891 pr_err("Platform Interrupt flag must be set to 1"); 892 rc = -EINVAL; 893 goto err; 894 } 895 896 if (pcc_mbox_ctrl->txdone_irq) { 897 rc = pcc_parse_subspace_irq(pchan, pcct_entry); 898 if (rc < 0) 899 goto err; 900 } 901 rc = pcc_parse_subspace_db_reg(pchan, pcct_entry); 902 if (rc < 0) 903 goto err; 904 905 pcc_parse_subspace_shmem(pchan, pcct_entry); 906 907 pchan->type = pcct_entry->type; 908 pcct_entry = (struct acpi_subtable_header *) 909 ((unsigned long) pcct_entry + pcct_entry->length); 910 } 911 912 pcc_mbox_ctrl->num_chans = count; 913 914 pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl->num_chans); 915 916 pcc_mbox_ctrl->chans = pcc_mbox_channels; 917 pcc_mbox_ctrl->ops = &pcc_chan_ops; 918 pcc_mbox_ctrl->dev = dev; 919 920 pr_info("Registering PCC driver as Mailbox controller\n"); 921 rc = mbox_controller_register(pcc_mbox_ctrl); 922 if (rc) 923 pr_err("Err registering PCC as Mailbox controller: %d\n", rc); 924 else 925 return 0; 926 err: 927 acpi_put_table(pcct_tbl); 928 return rc; 929 } 930 931 static struct platform_driver pcc_mbox_driver = { 932 .probe = pcc_mbox_probe, 933 .driver = { 934 .name = "PCCT", 935 }, 936 }; 937 938 static int __init pcc_init(void) 939 { 940 int ret; 941 struct platform_device *pcc_pdev; 942 943 if (acpi_disabled) 944 return -ENODEV; 945 946 /* Check if PCC support is available. */ 947 ret = acpi_pcc_probe(); 948 949 if (ret) { 950 pr_debug("ACPI PCC probe failed.\n"); 951 return -ENODEV; 952 } 953 954 pcc_pdev = platform_create_bundle(&pcc_mbox_driver, 955 pcc_mbox_probe, NULL, 0, NULL, 0); 956 957 if (IS_ERR(pcc_pdev)) { 958 pr_debug("Err creating PCC platform bundle\n"); 959 pcc_chan_count = 0; 960 return PTR_ERR(pcc_pdev); 961 } 962 963 return 0; 964 } 965 966 /* 967 * Make PCC init postcore so that users of this mailbox 968 * such as the ACPI Processor driver have it available 969 * at their init. 970 */ 971 postcore_initcall(pcc_init); 972