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 */
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 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 */
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
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 */
128static void read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
129{
130 switch (bit_width) {
131 case 8:
132 *val = readb(addr: vaddr);
133 break;
134 case 16:
135 *val = readw(addr: vaddr);
136 break;
137 case 32:
138 *val = readl(addr: vaddr);
139 break;
140 case 64:
141 *val = readq(addr: vaddr);
142 break;
143 }
144}
145
146static void write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
147{
148 switch (bit_width) {
149 case 8:
150 writeb(val, addr: vaddr);
151 break;
152 case 16:
153 writew(val, addr: vaddr);
154 break;
155 case 32:
156 writel(val, addr: vaddr);
157 break;
158 case 64:
159 writeq(val, addr: vaddr);
160 break;
161 }
162}
163
164static 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(vaddr: reg->vaddr, val, bit_width: reg->gas->bit_width);
175 else
176 ret = acpi_read(value: val, reg: reg->gas);
177
178 return ret;
179}
180
181static 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(vaddr: reg->vaddr, val, bit_width: reg->gas->bit_width);
190 else
191 ret = acpi_write(value: val, reg: reg->gas);
192
193 return ret;
194}
195
196static 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: &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 */
219static 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, gsi: interrupt, triggering: trigger, polarity);
233}
234
235static 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
241static 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(reg: &pchan->cmd_complete, val: &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
270static 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(reg: &pchan->error, val: &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(reg: &pchan->error, val);
283 return -EIO;
284 }
285
286 return 0;
287}
288
289static 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(reg: &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(reg: &pchan->db);
307}
308
309static 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 */
332static 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(reg: &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, r: 0);
369 }
370
371 mbox_chan_received_data(chan, data: 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 */
390struct pcc_mbox_chan *
391pcc_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(error: -ENOENT);
400
401 pchan = chan_info + subspace_id;
402 chan = pchan->chan.mchan;
403 if (IS_ERR(ptr: chan) || chan->cl) {
404 pr_err("Channel not found for idx: %d\n", subspace_id);
405 return ERR_PTR(error: -EBUSY);
406 }
407
408 rc = mbox_bind_client(chan, cl);
409 if (rc)
410 return ERR_PTR(error: rc);
411
412 pcc_mchan = &pchan->chan;
413 pcc_mchan->shmem = acpi_os_ioremap(phys: pcc_mchan->shmem_base_addr,
414 size: 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(reg: &pchan->cmd_update);
429
430 return pcc_mchan;
431
432err:
433 mbox_free_channel(chan);
434 return ERR_PTR(error: -ENXIO);
435}
436EXPORT_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 */
444void 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(addr: pcc_mbox_chan->shmem);
456 pcc_mbox_chan->shmem = NULL;
457 }
458
459 mbox_free_channel(chan);
460}
461EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
462
463static 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(reg: &pchan->cmd_complete, val: &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 */
505static 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(reg: &pchan->cmd_update);
515 if (ret)
516 return ret;
517
518 ret = pcc_chan_reg_read_modify_write(reg: &pchan->db);
519
520 if (!ret && pchan->plat_irq > 0)
521 pchan->chan_in_use = true;
522
523 return ret;
524}
525
526
527static 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(reg: &pchan->cmd_complete, val: &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 */
548static 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(dev: chan->mbox->dev, irq: pchan->plat_irq, handler: pcc_mbox_irq,
558 irqflags, MBOX_IRQ_NAME, dev_id: 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 */
574static 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(dev: chan->mbox->dev, irq: pchan->plat_irq, dev_id: chan);
580}
581
582static 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 */
599static 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
610static int
611pcc_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(n: 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(phys: gas->address, size: 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 */
647static 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(interrupt: pcct_ss->platform_interrupt,
659 flags: (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(reg: &pchan->plat_irq_ack,
671 gas: &pcct2_ss->platform_ack_register,
672 preserve_mask: pcct2_ss->ack_preserve_mask,
673 set_mask: pcct2_ss->ack_write_mask, status_mask: 0,
674 name: "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(reg: &pchan->plat_irq_ack,
681 gas: &pcct_ext->platform_ack_register,
682 preserve_mask: pcct_ext->ack_preserve_mask,
683 set_mask: pcct_ext->ack_set_mask, status_mask: 0,
684 name: "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 */
704static 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(reg: &pchan->db,
715 gas: &pcct_ss->doorbell_register,
716 preserve_mask: pcct_ss->preserve_mask,
717 set_mask: pcct_ss->write_mask, status_mask: 0, name: "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(reg: &pchan->db,
725 gas: &pcct_ext->doorbell_register,
726 preserve_mask: pcct_ext->preserve_mask,
727 set_mask: pcct_ext->write_mask, status_mask: 0, name: "Doorbell");
728 if (ret)
729 return ret;
730
731 ret = pcc_chan_reg_init(reg: &pchan->cmd_complete,
732 gas: &pcct_ext->cmd_complete_register,
733 preserve_mask: 0, set_mask: 0, status_mask: pcct_ext->cmd_complete_mask,
734 name: "Command Complete Check");
735 if (ret)
736 return ret;
737
738 ret = pcc_chan_reg_init(reg: &pchan->cmd_update,
739 gas: &pcct_ext->cmd_update_register,
740 preserve_mask: pcct_ext->cmd_update_preserve_mask,
741 set_mask: pcct_ext->cmd_update_set_mask, status_mask: 0,
742 name: "Command Complete Update");
743 if (ret)
744 return ret;
745
746 ret = pcc_chan_reg_init(reg: &pchan->error,
747 gas: &pcct_ext->error_status_register,
748 preserve_mask: 0, set_mask: 0, status_mask: pcct_ext->error_status_mask,
749 name: "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 */
761static 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 */
790static 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, instance: 0, out_table: &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 table_size: sizeof(struct acpi_table_pcct), proc,
811 proc_num: 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(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 */
839static 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, instance: 0, out_table: &pcct_tbl);
852
853 if (ACPI_FAILURE(status) || !pcct_tbl)
854 return -ENODEV;
855
856 pcc_mbox_channels = devm_kcalloc(dev, n: count, size: 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, n: count, size: sizeof(*chan_info), GFP_KERNEL);
864 if (!chan_info) {
865 rc = -ENOMEM;
866 goto err;
867 }
868
869 pcc_mbox_ctrl = devm_kzalloc(dev, size: 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(mbox: pcc_mbox_ctrl);
922 if (rc)
923 pr_err("Err registering PCC as Mailbox controller: %d\n", rc);
924 else
925 return 0;
926err:
927 acpi_put_table(table: pcct_tbl);
928 return rc;
929}
930
931static struct platform_driver pcc_mbox_driver = {
932 .probe = pcc_mbox_probe,
933 .driver = {
934 .name = "PCCT",
935 },
936};
937
938static 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(ptr: pcc_pdev)) {
958 pr_debug("Err creating PCC platform bundle\n");
959 pcc_chan_count = 0;
960 return PTR_ERR(ptr: 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 */
971postcore_initcall(pcc_init);
972