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1// SPDX-License-Identifier: GPL-2.0-or-later2/*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 clients8 * such as CPPC (Collaborative Processor Performance Control), RAS9 * (Reliability, Availability and Serviceability) and MPST (Memory10 * Node Power State Table) to talk to the platform (e.g. BMC) through11 * shared memory regions as defined in the PCC table entries. The PCC12 * specification supports a Doorbell mechanism for the PCC clients13 * to notify the platform about new data. This Doorbell information14 * 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 cmd21 * address.22 * * Client issues mbox_send_message() which rings the PCC doorbell23 * for its PCC channel.24 * * If command completes, then client has control over channel and25 * 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 a31 * channel lock.32 * * Client writes WRITE cmd in communication region cmd address.33 * * Client issues mbox_send_message() which rings the PCC doorbell34 * for its PCC channel.35 * * If command completes, then writes have succeeded and it can release36 * the channel lock.37 *38 * There is a Nominal latency defined for each channel which indicates39 * how long to wait until a command completes. If command is not complete40 * the client needs to retry or assume failure.41 *42 * For more details about PCC, please see the ACPI specification from43 * http://www.uefi.org/ACPIv5.1 Section 14.44 *45 * This file implements PCC as a Mailbox controller and allows for PCC46 * 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 bundle68 *69 * @vaddr: cached virtual address for this register70 * @gas: pointer to the generic address structure for this register71 * @preserve_mask: bitmask to preserve when writing to this register72 * @set_mask: bitmask to set when writing to this register73 * @status_mask: bitmask to determine and/or update the status for this register74 */75struct 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 information85 *86 * @chan: PCC channel information with Shared Memory Region info87 * @db: PCC register bundle for the doorbell register88 * @plat_irq_ack: PCC register bundle for the platform interrupt acknowledge89 * register90 * @cmd_complete: PCC register bundle for the command complete check register91 * @cmd_update: PCC register bundle for the command complete update register92 * @error: PCC register bundle for the error status register93 * @plat_irq: platform interrupt94 * @type: PCC subspace type95 * @plat_irq_flags: platform interrupt flags96 * @chan_in_use: this flag is used just to check if the interrupt needs97 * handling when it is shared. Since only one transfer can occur98 * at a time and mailbox takes care of locking, this flag can be99 * accessed without a lock. Note: the type only support the100 * communication from OSPM to Platform, like type3, use it, and101 * other types completely ignore it.102 */103struct 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)117static struct pcc_chan_info *chan_info;118static int pcc_chan_count;119 120static int pcc_send_data(struct mbox_chan *chan, void *data);121 122/*123 * PCC can be used with perf critical drivers such as CPPC124 * So it makes sense to locally cache the virtual address and125 * use it to read/write to PCC registers such as doorbell register126 *127 * The below read_register and write_registers are used to read and128 * write from perf critical registers such as PCC doorbell register129 */130static 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 148static 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 166static 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 else178 ret = acpi_read(val, reg->gas);179 180 return ret;181}182 183static 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 else193 ret = acpi_write(val, reg->gas);194 195 return ret;196}197 198static 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 number215 * @interrupt: GSI number.216 * @flags: interrupt flags217 *218 * Returns: a valid linux IRQ number on success219 * 0 or -EINVAL on failure220 */221static 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_SENSITIVE229 : ACPI_LEVEL_SENSITIVE;230 231 polarity = (flags & ACPI_PCCT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW232 : ACPI_ACTIVE_HIGH;233 234 return acpi_register_gsi(NULL, interrupt, trigger, polarity);235}236 237static 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 243static 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 of257 * command complete.258 */259 val &= pchan->cmd_complete.status_mask;260 261 /*262 * If this is PCC slave subspace channel, and the command complete263 * bit 0 indicates that Platform is sending a notification and OSPM264 * 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/**273 * pcc_mbox_irq - PCC mailbox interrupt handler274 * @irq: interrupt number275 * @p: data/cookie passed from the caller to identify the channel276 *277 * Returns: IRQ_HANDLED if interrupt is handled or IRQ_NONE if not278 */279static irqreturn_t pcc_mbox_irq(int irq, void *p)280{281 struct pcc_chan_info *pchan;282 struct mbox_chan *chan = p;283 u64 val;284 int ret;285 286 pchan = chan->con_priv;287 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE &&288 !pchan->chan_in_use)289 return IRQ_NONE;290 291 if (!pcc_mbox_cmd_complete_check(pchan))292 return IRQ_NONE;293 294 ret = pcc_chan_reg_read(&pchan->error, &val);295 if (ret)296 return IRQ_NONE;297 val &= pchan->error.status_mask;298 if (val) {299 val &= ~pchan->error.status_mask;300 pcc_chan_reg_write(&pchan->error, val);301 return IRQ_NONE;302 }303 304 if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack))305 return IRQ_NONE;306 307 mbox_chan_received_data(chan, NULL);308 309 /*310 * The PCC slave subspace channel needs to set the command complete bit311 * and ring doorbell after processing message.312 *313 * The PCC master subspace channel clears chan_in_use to free channel.314 */315 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)316 pcc_send_data(chan, NULL);317 pchan->chan_in_use = false;318 319 return IRQ_HANDLED;320}321 322/**323 * pcc_mbox_request_channel - PCC clients call this function to324 * request a pointer to their PCC subspace, from which they325 * can get the details of communicating with the remote.326 * @cl: Pointer to Mailbox client, so we know where to bind the327 * Channel.328 * @subspace_id: The PCC Subspace index as parsed in the PCC client329 * ACPI package. This is used to lookup the array of PCC330 * subspaces as parsed by the PCC Mailbox controller.331 *332 * Return: Pointer to the PCC Mailbox Channel if successful or ERR_PTR.333 */334struct pcc_mbox_chan *335pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)336{337 struct pcc_chan_info *pchan;338 struct mbox_chan *chan;339 int rc;340 341 if (subspace_id < 0 || subspace_id >= pcc_chan_count)342 return ERR_PTR(-ENOENT);343 344 pchan = chan_info + subspace_id;345 chan = pchan->chan.mchan;346 if (IS_ERR(chan) || chan->cl) {347 pr_err("Channel not found for idx: %d\n", subspace_id);348 return ERR_PTR(-EBUSY);349 }350 351 rc = mbox_bind_client(chan, cl);352 if (rc)353 return ERR_PTR(rc);354 355 return &pchan->chan;356}357EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);358 359/**360 * pcc_mbox_free_channel - Clients call this to free their Channel.361 *362 * @pchan: Pointer to the PCC mailbox channel as returned by363 * pcc_mbox_request_channel()364 */365void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan)366{367 struct mbox_chan *chan = pchan->mchan;368 369 if (!chan || !chan->cl)370 return;371 372 mbox_free_channel(chan);373}374EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);375 376/**377 * pcc_send_data - Called from Mailbox Controller code. Used378 * here only to ring the channel doorbell. The PCC client379 * specific read/write is done in the client driver in380 * order to maintain atomicity over PCC channel once381 * OS has control over it. See above for flow of operations.382 * @chan: Pointer to Mailbox channel over which to send data.383 * @data: Client specific data written over channel. Used here384 * only for debug after PCC transaction completes.385 *386 * Return: Err if something failed else 0 for success.387 */388static int pcc_send_data(struct mbox_chan *chan, void *data)389{390 int ret;391 struct pcc_chan_info *pchan = chan->con_priv;392 393 ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update);394 if (ret)395 return ret;396 397 ret = pcc_chan_reg_read_modify_write(&pchan->db);398 if (!ret && pchan->plat_irq > 0)399 pchan->chan_in_use = true;400 401 return ret;402}403 404/**405 * pcc_startup - Called from Mailbox Controller code. Used here406 * to request the interrupt.407 * @chan: Pointer to Mailbox channel to startup.408 *409 * Return: Err if something failed else 0 for success.410 */411static int pcc_startup(struct mbox_chan *chan)412{413 struct pcc_chan_info *pchan = chan->con_priv;414 unsigned long irqflags;415 int rc;416 417 if (pchan->plat_irq > 0) {418 irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ?419 IRQF_SHARED | IRQF_ONESHOT : 0;420 rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq,421 irqflags, MBOX_IRQ_NAME, chan);422 if (unlikely(rc)) {423 dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n",424 pchan->plat_irq);425 return rc;426 }427 }428 429 return 0;430}431 432/**433 * pcc_shutdown - Called from Mailbox Controller code. Used here434 * to free the interrupt.435 * @chan: Pointer to Mailbox channel to shutdown.436 */437static void pcc_shutdown(struct mbox_chan *chan)438{439 struct pcc_chan_info *pchan = chan->con_priv;440 441 if (pchan->plat_irq > 0)442 devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan);443}444 445static const struct mbox_chan_ops pcc_chan_ops = {446 .send_data = pcc_send_data,447 .startup = pcc_startup,448 .shutdown = pcc_shutdown,449};450 451/**452 * parse_pcc_subspace - Count PCC subspaces defined453 * @header: Pointer to the ACPI subtable header under the PCCT.454 * @end: End of subtable entry.455 *456 * Return: If we find a PCC subspace entry of a valid type, return 0.457 * Otherwise, return -EINVAL.458 *459 * This gets called for each entry in the PCC table.460 */461static int parse_pcc_subspace(union acpi_subtable_headers *header,462 const unsigned long end)463{464 struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header;465 466 if (ss->header.type < ACPI_PCCT_TYPE_RESERVED)467 return 0;468 469 return -EINVAL;470}471 472static int473pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas,474 u64 preserve_mask, u64 set_mask, u64 status_mask, char *name)475{476 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {477 if (!(gas->bit_width >= 8 && gas->bit_width <= 64 &&478 is_power_of_2(gas->bit_width))) {479 pr_err("Error: Cannot access register of %u bit width",480 gas->bit_width);481 return -EFAULT;482 }483 484 reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8);485 if (!reg->vaddr) {486 pr_err("Failed to ioremap PCC %s register\n", name);487 return -ENOMEM;488 }489 }490 reg->gas = gas;491 reg->preserve_mask = preserve_mask;492 reg->set_mask = set_mask;493 reg->status_mask = status_mask;494 return 0;495}496 497/**498 * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register499 *500 * @pchan: Pointer to the PCC channel info structure.501 * @pcct_entry: Pointer to the ACPI subtable header.502 *503 * Return: 0 for Success, else errno.504 *505 * There should be one entry per PCC channel. This gets called for each506 * entry in the PCC table. This uses PCCY Type1 structure for all applicable507 * types(Type 1-4) to fetch irq508 */509static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan,510 struct acpi_subtable_header *pcct_entry)511{512 int ret = 0;513 struct acpi_pcct_hw_reduced *pcct_ss;514 515 if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE ||516 pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)517 return 0;518 519 pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry;520 pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt,521 (u32)pcct_ss->flags);522 if (pchan->plat_irq <= 0) {523 pr_err("PCC GSI %d not registered\n",524 pcct_ss->platform_interrupt);525 return -EINVAL;526 }527 pchan->plat_irq_flags = pcct_ss->flags;528 529 if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {530 struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;531 532 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,533 &pcct2_ss->platform_ack_register,534 pcct2_ss->ack_preserve_mask,535 pcct2_ss->ack_write_mask, 0,536 "PLAT IRQ ACK");537 538 } else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE ||539 pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) {540 struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss;541 542 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,543 &pcct_ext->platform_ack_register,544 pcct_ext->ack_preserve_mask,545 pcct_ext->ack_set_mask, 0,546 "PLAT IRQ ACK");547 }548 549 if (pcc_chan_plat_irq_can_be_shared(pchan) &&550 !pchan->plat_irq_ack.gas) {551 pr_err("PCC subspace has level IRQ with no ACK register\n");552 return -EINVAL;553 }554 555 return ret;556}557 558/**559 * pcc_parse_subspace_db_reg - Parse the PCC doorbell register560 *561 * @pchan: Pointer to the PCC channel info structure.562 * @pcct_entry: Pointer to the ACPI subtable header.563 *564 * Return: 0 for Success, else errno.565 */566static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan,567 struct acpi_subtable_header *pcct_entry)568{569 int ret = 0;570 571 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {572 struct acpi_pcct_subspace *pcct_ss;573 574 pcct_ss = (struct acpi_pcct_subspace *)pcct_entry;575 576 ret = pcc_chan_reg_init(&pchan->db,577 &pcct_ss->doorbell_register,578 pcct_ss->preserve_mask,579 pcct_ss->write_mask, 0, "Doorbell");580 581 } else {582 struct acpi_pcct_ext_pcc_master *pcct_ext;583 584 pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry;585 586 ret = pcc_chan_reg_init(&pchan->db,587 &pcct_ext->doorbell_register,588 pcct_ext->preserve_mask,589 pcct_ext->write_mask, 0, "Doorbell");590 if (ret)591 return ret;592 593 ret = pcc_chan_reg_init(&pchan->cmd_complete,594 &pcct_ext->cmd_complete_register,595 0, 0, pcct_ext->cmd_complete_mask,596 "Command Complete Check");597 if (ret)598 return ret;599 600 ret = pcc_chan_reg_init(&pchan->cmd_update,601 &pcct_ext->cmd_update_register,602 pcct_ext->cmd_update_preserve_mask,603 pcct_ext->cmd_update_set_mask, 0,604 "Command Complete Update");605 if (ret)606 return ret;607 608 ret = pcc_chan_reg_init(&pchan->error,609 &pcct_ext->error_status_register,610 0, 0, pcct_ext->error_status_mask,611 "Error Status");612 }613 return ret;614}615 616/**617 * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information618 *619 * @pchan: Pointer to the PCC channel info structure.620 * @pcct_entry: Pointer to the ACPI subtable header.621 *622 */623static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan,624 struct acpi_subtable_header *pcct_entry)625{626 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {627 struct acpi_pcct_subspace *pcct_ss =628 (struct acpi_pcct_subspace *)pcct_entry;629 630 pchan->chan.shmem_base_addr = pcct_ss->base_address;631 pchan->chan.shmem_size = pcct_ss->length;632 pchan->chan.latency = pcct_ss->latency;633 pchan->chan.max_access_rate = pcct_ss->max_access_rate;634 pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time;635 } else {636 struct acpi_pcct_ext_pcc_master *pcct_ext =637 (struct acpi_pcct_ext_pcc_master *)pcct_entry;638 639 pchan->chan.shmem_base_addr = pcct_ext->base_address;640 pchan->chan.shmem_size = pcct_ext->length;641 pchan->chan.latency = pcct_ext->latency;642 pchan->chan.max_access_rate = pcct_ext->max_access_rate;643 pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time;644 }645}646 647/**648 * acpi_pcc_probe - Parse the ACPI tree for the PCCT.649 *650 * Return: 0 for Success, else errno.651 */652static int __init acpi_pcc_probe(void)653{654 int count, i, rc = 0;655 acpi_status status;656 struct acpi_table_header *pcct_tbl;657 struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED];658 659 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);660 if (ACPI_FAILURE(status) || !pcct_tbl)661 return -ENODEV;662 663 /* Set up the subtable handlers */664 for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE;665 i < ACPI_PCCT_TYPE_RESERVED; i++) {666 proc[i].id = i;667 proc[i].count = 0;668 proc[i].handler = parse_pcc_subspace;669 }670 671 count = acpi_table_parse_entries_array(ACPI_SIG_PCCT,672 sizeof(struct acpi_table_pcct), proc,673 ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES);674 if (count <= 0 || count > MAX_PCC_SUBSPACES) {675 if (count < 0)676 pr_warn("Error parsing PCC subspaces from PCCT\n");677 else678 pr_warn("Invalid PCCT: %d PCC subspaces\n", count);679 680 rc = -EINVAL;681 } else {682 pcc_chan_count = count;683 }684 685 acpi_put_table(pcct_tbl);686 687 return rc;688}689 690/**691 * pcc_mbox_probe - Called when we find a match for the692 * PCCT platform device. This is purely used to represent693 * the PCCT as a virtual device for registering with the694 * generic Mailbox framework.695 *696 * @pdev: Pointer to platform device returned when a match697 * is found.698 *699 * Return: 0 for Success, else errno.700 */701static int pcc_mbox_probe(struct platform_device *pdev)702{703 struct device *dev = &pdev->dev;704 struct mbox_controller *pcc_mbox_ctrl;705 struct mbox_chan *pcc_mbox_channels;706 struct acpi_table_header *pcct_tbl;707 struct acpi_subtable_header *pcct_entry;708 struct acpi_table_pcct *acpi_pcct_tbl;709 acpi_status status = AE_OK;710 int i, rc, count = pcc_chan_count;711 712 /* Search for PCCT */713 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);714 715 if (ACPI_FAILURE(status) || !pcct_tbl)716 return -ENODEV;717 718 pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels),719 GFP_KERNEL);720 if (!pcc_mbox_channels) {721 rc = -ENOMEM;722 goto err;723 }724 725 chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL);726 if (!chan_info) {727 rc = -ENOMEM;728 goto err;729 }730 731 pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL);732 if (!pcc_mbox_ctrl) {733 rc = -ENOMEM;734 goto err;735 }736 737 /* Point to the first PCC subspace entry */738 pcct_entry = (struct acpi_subtable_header *) (739 (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct));740 741 acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl;742 if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL)743 pcc_mbox_ctrl->txdone_irq = true;744 745 for (i = 0; i < count; i++) {746 struct pcc_chan_info *pchan = chan_info + i;747 748 pcc_mbox_channels[i].con_priv = pchan;749 pchan->chan.mchan = &pcc_mbox_channels[i];750 751 if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE &&752 !pcc_mbox_ctrl->txdone_irq) {753 pr_err("Platform Interrupt flag must be set to 1");754 rc = -EINVAL;755 goto err;756 }757 758 if (pcc_mbox_ctrl->txdone_irq) {759 rc = pcc_parse_subspace_irq(pchan, pcct_entry);760 if (rc < 0)761 goto err;762 }763 rc = pcc_parse_subspace_db_reg(pchan, pcct_entry);764 if (rc < 0)765 goto err;766 767 pcc_parse_subspace_shmem(pchan, pcct_entry);768 769 pchan->type = pcct_entry->type;770 pcct_entry = (struct acpi_subtable_header *)771 ((unsigned long) pcct_entry + pcct_entry->length);772 }773 774 pcc_mbox_ctrl->num_chans = count;775 776 pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl->num_chans);777 778 pcc_mbox_ctrl->chans = pcc_mbox_channels;779 pcc_mbox_ctrl->ops = &pcc_chan_ops;780 pcc_mbox_ctrl->dev = dev;781 782 pr_info("Registering PCC driver as Mailbox controller\n");783 rc = mbox_controller_register(pcc_mbox_ctrl);784 if (rc)785 pr_err("Err registering PCC as Mailbox controller: %d\n", rc);786 else787 return 0;788err:789 acpi_put_table(pcct_tbl);790 return rc;791}792 793static struct platform_driver pcc_mbox_driver = {794 .probe = pcc_mbox_probe,795 .driver = {796 .name = "PCCT",797 },798};799 800static int __init pcc_init(void)801{802 int ret;803 struct platform_device *pcc_pdev;804 805 if (acpi_disabled)806 return -ENODEV;807 808 /* Check if PCC support is available. */809 ret = acpi_pcc_probe();810 811 if (ret) {812 pr_debug("ACPI PCC probe failed.\n");813 return -ENODEV;814 }815 816 pcc_pdev = platform_create_bundle(&pcc_mbox_driver,817 pcc_mbox_probe, NULL, 0, NULL, 0);818 819 if (IS_ERR(pcc_pdev)) {820 pr_debug("Err creating PCC platform bundle\n");821 pcc_chan_count = 0;822 return PTR_ERR(pcc_pdev);823 }824 825 return 0;826}827 828/*829 * Make PCC init postcore so that users of this mailbox830 * such as the ACPI Processor driver have it available831 * at their init.832 */833postcore_initcall(pcc_init);834