Loading...
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 */
95struct pcc_chan_info {
96 struct pcc_mbox_chan chan;
97 struct pcc_chan_reg db;
98 struct pcc_chan_reg plat_irq_ack;
99 struct pcc_chan_reg cmd_complete;
100 struct pcc_chan_reg cmd_update;
101 struct pcc_chan_reg error;
102 int plat_irq;
103};
104
105#define to_pcc_chan_info(c) container_of(c, struct pcc_chan_info, chan)
106static struct pcc_chan_info *chan_info;
107static int pcc_chan_count;
108
109/*
110 * PCC can be used with perf critical drivers such as CPPC
111 * So it makes sense to locally cache the virtual address and
112 * use it to read/write to PCC registers such as doorbell register
113 *
114 * The below read_register and write_registers are used to read and
115 * write from perf critical registers such as PCC doorbell register
116 */
117static void read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
118{
119 switch (bit_width) {
120 case 8:
121 *val = readb(vaddr);
122 break;
123 case 16:
124 *val = readw(vaddr);
125 break;
126 case 32:
127 *val = readl(vaddr);
128 break;
129 case 64:
130 *val = readq(vaddr);
131 break;
132 }
133}
134
135static void write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
136{
137 switch (bit_width) {
138 case 8:
139 writeb(val, vaddr);
140 break;
141 case 16:
142 writew(val, vaddr);
143 break;
144 case 32:
145 writel(val, vaddr);
146 break;
147 case 64:
148 writeq(val, vaddr);
149 break;
150 }
151}
152
153static int pcc_chan_reg_read(struct pcc_chan_reg *reg, u64 *val)
154{
155 int ret = 0;
156
157 if (!reg->gas) {
158 *val = 0;
159 return 0;
160 }
161
162 if (reg->vaddr)
163 read_register(reg->vaddr, val, reg->gas->bit_width);
164 else
165 ret = acpi_read(val, reg->gas);
166
167 return ret;
168}
169
170static int pcc_chan_reg_write(struct pcc_chan_reg *reg, u64 val)
171{
172 int ret = 0;
173
174 if (!reg->gas)
175 return 0;
176
177 if (reg->vaddr)
178 write_register(reg->vaddr, val, reg->gas->bit_width);
179 else
180 ret = acpi_write(val, reg->gas);
181
182 return ret;
183}
184
185static int pcc_chan_reg_read_modify_write(struct pcc_chan_reg *reg)
186{
187 int ret = 0;
188 u64 val;
189
190 ret = pcc_chan_reg_read(reg, &val);
191 if (ret)
192 return ret;
193
194 val &= reg->preserve_mask;
195 val |= reg->set_mask;
196
197 return pcc_chan_reg_write(reg, val);
198}
199
200/**
201 * pcc_map_interrupt - Map a PCC subspace GSI to a linux IRQ number
202 * @interrupt: GSI number.
203 * @flags: interrupt flags
204 *
205 * Returns: a valid linux IRQ number on success
206 * 0 or -EINVAL on failure
207 */
208static int pcc_map_interrupt(u32 interrupt, u32 flags)
209{
210 int trigger, polarity;
211
212 if (!interrupt)
213 return 0;
214
215 trigger = (flags & ACPI_PCCT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
216 : ACPI_LEVEL_SENSITIVE;
217
218 polarity = (flags & ACPI_PCCT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
219 : ACPI_ACTIVE_HIGH;
220
221 return acpi_register_gsi(NULL, interrupt, trigger, polarity);
222}
223
224/**
225 * pcc_mbox_irq - PCC mailbox interrupt handler
226 * @irq: interrupt number
227 * @p: data/cookie passed from the caller to identify the channel
228 *
229 * Returns: IRQ_HANDLED if interrupt is handled or IRQ_NONE if not
230 */
231static irqreturn_t pcc_mbox_irq(int irq, void *p)
232{
233 struct pcc_chan_info *pchan;
234 struct mbox_chan *chan = p;
235 u64 val;
236 int ret;
237
238 pchan = chan->con_priv;
239
240 ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
241 if (ret)
242 return IRQ_NONE;
243
244 if (val) { /* Ensure GAS exists and value is non-zero */
245 val &= pchan->cmd_complete.status_mask;
246 if (!val)
247 return IRQ_NONE;
248 }
249
250 ret = pcc_chan_reg_read(&pchan->error, &val);
251 if (ret)
252 return IRQ_NONE;
253 val &= pchan->error.status_mask;
254 if (val) {
255 val &= ~pchan->error.status_mask;
256 pcc_chan_reg_write(&pchan->error, val);
257 return IRQ_NONE;
258 }
259
260 if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack))
261 return IRQ_NONE;
262
263 mbox_chan_received_data(chan, NULL);
264
265 return IRQ_HANDLED;
266}
267
268/**
269 * pcc_mbox_request_channel - PCC clients call this function to
270 * request a pointer to their PCC subspace, from which they
271 * can get the details of communicating with the remote.
272 * @cl: Pointer to Mailbox client, so we know where to bind the
273 * Channel.
274 * @subspace_id: The PCC Subspace index as parsed in the PCC client
275 * ACPI package. This is used to lookup the array of PCC
276 * subspaces as parsed by the PCC Mailbox controller.
277 *
278 * Return: Pointer to the PCC Mailbox Channel if successful or ERR_PTR.
279 */
280struct pcc_mbox_chan *
281pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
282{
283 struct pcc_chan_info *pchan;
284 struct mbox_chan *chan;
285 struct device *dev;
286 unsigned long flags;
287
288 if (subspace_id < 0 || subspace_id >= pcc_chan_count)
289 return ERR_PTR(-ENOENT);
290
291 pchan = chan_info + subspace_id;
292 chan = pchan->chan.mchan;
293 if (IS_ERR(chan) || chan->cl) {
294 pr_err("Channel not found for idx: %d\n", subspace_id);
295 return ERR_PTR(-EBUSY);
296 }
297 dev = chan->mbox->dev;
298
299 spin_lock_irqsave(&chan->lock, flags);
300 chan->msg_free = 0;
301 chan->msg_count = 0;
302 chan->active_req = NULL;
303 chan->cl = cl;
304 init_completion(&chan->tx_complete);
305
306 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
307 chan->txdone_method = TXDONE_BY_ACK;
308
309 spin_unlock_irqrestore(&chan->lock, flags);
310
311 if (pchan->plat_irq > 0) {
312 int rc;
313
314 rc = devm_request_irq(dev, pchan->plat_irq, pcc_mbox_irq, 0,
315 MBOX_IRQ_NAME, chan);
316 if (unlikely(rc)) {
317 dev_err(dev, "failed to register PCC interrupt %d\n",
318 pchan->plat_irq);
319 pcc_mbox_free_channel(&pchan->chan);
320 return ERR_PTR(rc);
321 }
322 }
323
324 return &pchan->chan;
325}
326EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
327
328/**
329 * pcc_mbox_free_channel - Clients call this to free their Channel.
330 *
331 * @pchan: Pointer to the PCC mailbox channel as returned by
332 * pcc_mbox_request_channel()
333 */
334void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan)
335{
336 struct pcc_chan_info *pchan_info = to_pcc_chan_info(pchan);
337 struct mbox_chan *chan = pchan->mchan;
338 unsigned long flags;
339
340 if (!chan || !chan->cl)
341 return;
342
343 if (pchan_info->plat_irq > 0)
344 devm_free_irq(chan->mbox->dev, pchan_info->plat_irq, chan);
345
346 spin_lock_irqsave(&chan->lock, flags);
347 chan->cl = NULL;
348 chan->active_req = NULL;
349 if (chan->txdone_method == TXDONE_BY_ACK)
350 chan->txdone_method = TXDONE_BY_POLL;
351
352 spin_unlock_irqrestore(&chan->lock, flags);
353}
354EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
355
356/**
357 * pcc_send_data - Called from Mailbox Controller code. Used
358 * here only to ring the channel doorbell. The PCC client
359 * specific read/write is done in the client driver in
360 * order to maintain atomicity over PCC channel once
361 * OS has control over it. See above for flow of operations.
362 * @chan: Pointer to Mailbox channel over which to send data.
363 * @data: Client specific data written over channel. Used here
364 * only for debug after PCC transaction completes.
365 *
366 * Return: Err if something failed else 0 for success.
367 */
368static int pcc_send_data(struct mbox_chan *chan, void *data)
369{
370 int ret;
371 struct pcc_chan_info *pchan = chan->con_priv;
372
373 ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update);
374 if (ret)
375 return ret;
376
377 return pcc_chan_reg_read_modify_write(&pchan->db);
378}
379
380static const struct mbox_chan_ops pcc_chan_ops = {
381 .send_data = pcc_send_data,
382};
383
384/**
385 * parse_pcc_subspace - Count PCC subspaces defined
386 * @header: Pointer to the ACPI subtable header under the PCCT.
387 * @end: End of subtable entry.
388 *
389 * Return: If we find a PCC subspace entry of a valid type, return 0.
390 * Otherwise, return -EINVAL.
391 *
392 * This gets called for each entry in the PCC table.
393 */
394static int parse_pcc_subspace(union acpi_subtable_headers *header,
395 const unsigned long end)
396{
397 struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header;
398
399 if (ss->header.type < ACPI_PCCT_TYPE_RESERVED)
400 return 0;
401
402 return -EINVAL;
403}
404
405static int
406pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas,
407 u64 preserve_mask, u64 set_mask, u64 status_mask, char *name)
408{
409 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
410 if (!(gas->bit_width >= 8 && gas->bit_width <= 64 &&
411 is_power_of_2(gas->bit_width))) {
412 pr_err("Error: Cannot access register of %u bit width",
413 gas->bit_width);
414 return -EFAULT;
415 }
416
417 reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8);
418 if (!reg->vaddr) {
419 pr_err("Failed to ioremap PCC %s register\n", name);
420 return -ENOMEM;
421 }
422 }
423 reg->gas = gas;
424 reg->preserve_mask = preserve_mask;
425 reg->set_mask = set_mask;
426 reg->status_mask = status_mask;
427 return 0;
428}
429
430/**
431 * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register
432 *
433 * @pchan: Pointer to the PCC channel info structure.
434 * @pcct_entry: Pointer to the ACPI subtable header.
435 *
436 * Return: 0 for Success, else errno.
437 *
438 * There should be one entry per PCC channel. This gets called for each
439 * entry in the PCC table. This uses PCCY Type1 structure for all applicable
440 * types(Type 1-4) to fetch irq
441 */
442static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan,
443 struct acpi_subtable_header *pcct_entry)
444{
445 int ret = 0;
446 struct acpi_pcct_hw_reduced *pcct_ss;
447
448 if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE ||
449 pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
450 return 0;
451
452 pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry;
453 pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt,
454 (u32)pcct_ss->flags);
455 if (pchan->plat_irq <= 0) {
456 pr_err("PCC GSI %d not registered\n",
457 pcct_ss->platform_interrupt);
458 return -EINVAL;
459 }
460
461 if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
462 struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;
463
464 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
465 &pcct2_ss->platform_ack_register,
466 pcct2_ss->ack_preserve_mask,
467 pcct2_ss->ack_write_mask, 0,
468 "PLAT IRQ ACK");
469
470 } else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE ||
471 pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) {
472 struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss;
473
474 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
475 &pcct_ext->platform_ack_register,
476 pcct_ext->ack_preserve_mask,
477 pcct_ext->ack_set_mask, 0,
478 "PLAT IRQ ACK");
479 }
480
481 return ret;
482}
483
484/**
485 * pcc_parse_subspace_db_reg - Parse the PCC doorbell register
486 *
487 * @pchan: Pointer to the PCC channel info structure.
488 * @pcct_entry: Pointer to the ACPI subtable header.
489 *
490 * Return: 0 for Success, else errno.
491 */
492static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan,
493 struct acpi_subtable_header *pcct_entry)
494{
495 int ret = 0;
496
497 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
498 struct acpi_pcct_subspace *pcct_ss;
499
500 pcct_ss = (struct acpi_pcct_subspace *)pcct_entry;
501
502 ret = pcc_chan_reg_init(&pchan->db,
503 &pcct_ss->doorbell_register,
504 pcct_ss->preserve_mask,
505 pcct_ss->write_mask, 0, "Doorbell");
506
507 } else {
508 struct acpi_pcct_ext_pcc_master *pcct_ext;
509
510 pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry;
511
512 ret = pcc_chan_reg_init(&pchan->db,
513 &pcct_ext->doorbell_register,
514 pcct_ext->preserve_mask,
515 pcct_ext->write_mask, 0, "Doorbell");
516 if (ret)
517 return ret;
518
519 ret = pcc_chan_reg_init(&pchan->cmd_complete,
520 &pcct_ext->cmd_complete_register,
521 0, 0, pcct_ext->cmd_complete_mask,
522 "Command Complete Check");
523 if (ret)
524 return ret;
525
526 ret = pcc_chan_reg_init(&pchan->cmd_update,
527 &pcct_ext->cmd_update_register,
528 pcct_ext->cmd_update_preserve_mask,
529 pcct_ext->cmd_update_set_mask, 0,
530 "Command Complete Update");
531 if (ret)
532 return ret;
533
534 ret = pcc_chan_reg_init(&pchan->error,
535 &pcct_ext->error_status_register,
536 0, 0, pcct_ext->error_status_mask,
537 "Error Status");
538 }
539 return ret;
540}
541
542/**
543 * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information
544 *
545 * @pchan: Pointer to the PCC channel info structure.
546 * @pcct_entry: Pointer to the ACPI subtable header.
547 *
548 */
549static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan,
550 struct acpi_subtable_header *pcct_entry)
551{
552 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
553 struct acpi_pcct_subspace *pcct_ss =
554 (struct acpi_pcct_subspace *)pcct_entry;
555
556 pchan->chan.shmem_base_addr = pcct_ss->base_address;
557 pchan->chan.shmem_size = pcct_ss->length;
558 pchan->chan.latency = pcct_ss->latency;
559 pchan->chan.max_access_rate = pcct_ss->max_access_rate;
560 pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time;
561 } else {
562 struct acpi_pcct_ext_pcc_master *pcct_ext =
563 (struct acpi_pcct_ext_pcc_master *)pcct_entry;
564
565 pchan->chan.shmem_base_addr = pcct_ext->base_address;
566 pchan->chan.shmem_size = pcct_ext->length;
567 pchan->chan.latency = pcct_ext->latency;
568 pchan->chan.max_access_rate = pcct_ext->max_access_rate;
569 pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time;
570 }
571}
572
573/**
574 * acpi_pcc_probe - Parse the ACPI tree for the PCCT.
575 *
576 * Return: 0 for Success, else errno.
577 */
578static int __init acpi_pcc_probe(void)
579{
580 int count, i, rc = 0;
581 acpi_status status;
582 struct acpi_table_header *pcct_tbl;
583 struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED];
584
585 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
586 if (ACPI_FAILURE(status) || !pcct_tbl)
587 return -ENODEV;
588
589 /* Set up the subtable handlers */
590 for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE;
591 i < ACPI_PCCT_TYPE_RESERVED; i++) {
592 proc[i].id = i;
593 proc[i].count = 0;
594 proc[i].handler = parse_pcc_subspace;
595 }
596
597 count = acpi_table_parse_entries_array(ACPI_SIG_PCCT,
598 sizeof(struct acpi_table_pcct), proc,
599 ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES);
600 if (count <= 0 || count > MAX_PCC_SUBSPACES) {
601 if (count < 0)
602 pr_warn("Error parsing PCC subspaces from PCCT\n");
603 else
604 pr_warn("Invalid PCCT: %d PCC subspaces\n", count);
605
606 rc = -EINVAL;
607 } else {
608 pcc_chan_count = count;
609 }
610
611 acpi_put_table(pcct_tbl);
612
613 return rc;
614}
615
616/**
617 * pcc_mbox_probe - Called when we find a match for the
618 * PCCT platform device. This is purely used to represent
619 * the PCCT as a virtual device for registering with the
620 * generic Mailbox framework.
621 *
622 * @pdev: Pointer to platform device returned when a match
623 * is found.
624 *
625 * Return: 0 for Success, else errno.
626 */
627static int pcc_mbox_probe(struct platform_device *pdev)
628{
629 struct device *dev = &pdev->dev;
630 struct mbox_controller *pcc_mbox_ctrl;
631 struct mbox_chan *pcc_mbox_channels;
632 struct acpi_table_header *pcct_tbl;
633 struct acpi_subtable_header *pcct_entry;
634 struct acpi_table_pcct *acpi_pcct_tbl;
635 acpi_status status = AE_OK;
636 int i, rc, count = pcc_chan_count;
637
638 /* Search for PCCT */
639 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
640
641 if (ACPI_FAILURE(status) || !pcct_tbl)
642 return -ENODEV;
643
644 pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels),
645 GFP_KERNEL);
646 if (!pcc_mbox_channels) {
647 rc = -ENOMEM;
648 goto err;
649 }
650
651 chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL);
652 if (!chan_info) {
653 rc = -ENOMEM;
654 goto err;
655 }
656
657 pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL);
658 if (!pcc_mbox_ctrl) {
659 rc = -ENOMEM;
660 goto err;
661 }
662
663 /* Point to the first PCC subspace entry */
664 pcct_entry = (struct acpi_subtable_header *) (
665 (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct));
666
667 acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl;
668 if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL)
669 pcc_mbox_ctrl->txdone_irq = true;
670
671 for (i = 0; i < count; i++) {
672 struct pcc_chan_info *pchan = chan_info + i;
673
674 pcc_mbox_channels[i].con_priv = pchan;
675 pchan->chan.mchan = &pcc_mbox_channels[i];
676
677 if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE &&
678 !pcc_mbox_ctrl->txdone_irq) {
679 pr_err("Platform Interrupt flag must be set to 1");
680 rc = -EINVAL;
681 goto err;
682 }
683
684 if (pcc_mbox_ctrl->txdone_irq) {
685 rc = pcc_parse_subspace_irq(pchan, pcct_entry);
686 if (rc < 0)
687 goto err;
688 }
689 rc = pcc_parse_subspace_db_reg(pchan, pcct_entry);
690 if (rc < 0)
691 goto err;
692
693 pcc_parse_subspace_shmem(pchan, pcct_entry);
694
695 pcct_entry = (struct acpi_subtable_header *)
696 ((unsigned long) pcct_entry + pcct_entry->length);
697 }
698
699 pcc_mbox_ctrl->num_chans = count;
700
701 pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl->num_chans);
702
703 pcc_mbox_ctrl->chans = pcc_mbox_channels;
704 pcc_mbox_ctrl->ops = &pcc_chan_ops;
705 pcc_mbox_ctrl->dev = dev;
706
707 pr_info("Registering PCC driver as Mailbox controller\n");
708 rc = mbox_controller_register(pcc_mbox_ctrl);
709 if (rc)
710 pr_err("Err registering PCC as Mailbox controller: %d\n", rc);
711 else
712 return 0;
713err:
714 acpi_put_table(pcct_tbl);
715 return rc;
716}
717
718static struct platform_driver pcc_mbox_driver = {
719 .probe = pcc_mbox_probe,
720 .driver = {
721 .name = "PCCT",
722 },
723};
724
725static int __init pcc_init(void)
726{
727 int ret;
728 struct platform_device *pcc_pdev;
729
730 if (acpi_disabled)
731 return -ENODEV;
732
733 /* Check if PCC support is available. */
734 ret = acpi_pcc_probe();
735
736 if (ret) {
737 pr_debug("ACPI PCC probe failed.\n");
738 return -ENODEV;
739 }
740
741 pcc_pdev = platform_create_bundle(&pcc_mbox_driver,
742 pcc_mbox_probe, NULL, 0, NULL, 0);
743
744 if (IS_ERR(pcc_pdev)) {
745 pr_debug("Err creating PCC platform bundle\n");
746 pcc_chan_count = 0;
747 return PTR_ERR(pcc_pdev);
748 }
749
750 return 0;
751}
752
753/*
754 * Make PCC init postcore so that users of this mailbox
755 * such as the ACPI Processor driver have it available
756 * at their init.
757 */
758postcore_initcall(pcc_init);
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
120static 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 */
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 else
178 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 else
193 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 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 */
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_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
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 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
272static 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 */
308static 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 */
356struct pcc_mbox_chan *
357pcc_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}
379EXPORT_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 */
387void 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}
404EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
405
406int 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}
419EXPORT_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 */
433static 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 */
456static 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 */
482static 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
490static 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 */
506static 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
517static int
518pcc_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 */
554static 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 */
611static 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 */
668static 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 */
697static 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 */
746static 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;
833err:
834 acpi_put_table(pcct_tbl);
835 return rc;
836}
837
838static struct platform_driver pcc_mbox_driver = {
839 .probe = pcc_mbox_probe,
840 .driver = {
841 .name = "PCCT",
842 },
843};
844
845static 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 */
878postcore_initcall(pcc_init);