Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#define MBOX_IRQ_NAME "pcc-mbox"
63
64/**
65 * struct pcc_chan_reg - PCC register bundle
66 *
67 * @vaddr: cached virtual address for this register
68 * @gas: pointer to the generic address structure for this register
69 * @preserve_mask: bitmask to preserve when writing to this register
70 * @set_mask: bitmask to set when writing to this register
71 * @status_mask: bitmask to determine and/or update the status for this register
72 */
73struct pcc_chan_reg {
74 void __iomem *vaddr;
75 struct acpi_generic_address *gas;
76 u64 preserve_mask;
77 u64 set_mask;
78 u64 status_mask;
79};
80
81/**
82 * struct pcc_chan_info - PCC channel specific information
83 *
84 * @chan: PCC channel information with Shared Memory Region info
85 * @db: PCC register bundle for the doorbell register
86 * @plat_irq_ack: PCC register bundle for the platform interrupt acknowledge
87 * register
88 * @cmd_complete: PCC register bundle for the command complete check register
89 * @cmd_update: PCC register bundle for the command complete update register
90 * @error: PCC register bundle for the error status register
91 * @plat_irq: platform interrupt
92 * @type: PCC subspace type
93 * @plat_irq_flags: platform interrupt flags
94 * @chan_in_use: this flag is used just to check if the interrupt needs
95 * handling when it is shared. Since only one transfer can occur
96 * at a time and mailbox takes care of locking, this flag can be
97 * accessed without a lock. Note: the type only support the
98 * communication from OSPM to Platform, like type3, use it, and
99 * other types completely ignore it.
100 */
101struct pcc_chan_info {
102 struct pcc_mbox_chan chan;
103 struct pcc_chan_reg db;
104 struct pcc_chan_reg plat_irq_ack;
105 struct pcc_chan_reg cmd_complete;
106 struct pcc_chan_reg cmd_update;
107 struct pcc_chan_reg error;
108 int plat_irq;
109 u8 type;
110 unsigned int plat_irq_flags;
111 bool chan_in_use;
112};
113
114#define to_pcc_chan_info(c) container_of(c, struct pcc_chan_info, chan)
115static struct pcc_chan_info *chan_info;
116static int pcc_chan_count;
117
118/*
119 * PCC can be used with perf critical drivers such as CPPC
120 * So it makes sense to locally cache the virtual address and
121 * use it to read/write to PCC registers such as doorbell register
122 *
123 * The below read_register and write_registers are used to read and
124 * write from perf critical registers such as PCC doorbell register
125 */
126static void read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
127{
128 switch (bit_width) {
129 case 8:
130 *val = readb(vaddr);
131 break;
132 case 16:
133 *val = readw(vaddr);
134 break;
135 case 32:
136 *val = readl(vaddr);
137 break;
138 case 64:
139 *val = readq(vaddr);
140 break;
141 }
142}
143
144static void write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
145{
146 switch (bit_width) {
147 case 8:
148 writeb(val, vaddr);
149 break;
150 case 16:
151 writew(val, vaddr);
152 break;
153 case 32:
154 writel(val, vaddr);
155 break;
156 case 64:
157 writeq(val, vaddr);
158 break;
159 }
160}
161
162static int pcc_chan_reg_read(struct pcc_chan_reg *reg, u64 *val)
163{
164 int ret = 0;
165
166 if (!reg->gas) {
167 *val = 0;
168 return 0;
169 }
170
171 if (reg->vaddr)
172 read_register(reg->vaddr, val, reg->gas->bit_width);
173 else
174 ret = acpi_read(val, reg->gas);
175
176 return ret;
177}
178
179static int pcc_chan_reg_write(struct pcc_chan_reg *reg, u64 val)
180{
181 int ret = 0;
182
183 if (!reg->gas)
184 return 0;
185
186 if (reg->vaddr)
187 write_register(reg->vaddr, val, reg->gas->bit_width);
188 else
189 ret = acpi_write(val, reg->gas);
190
191 return ret;
192}
193
194static int pcc_chan_reg_read_modify_write(struct pcc_chan_reg *reg)
195{
196 int ret = 0;
197 u64 val;
198
199 ret = pcc_chan_reg_read(reg, &val);
200 if (ret)
201 return ret;
202
203 val &= reg->preserve_mask;
204 val |= reg->set_mask;
205
206 return pcc_chan_reg_write(reg, val);
207}
208
209/**
210 * pcc_map_interrupt - Map a PCC subspace GSI to a linux IRQ number
211 * @interrupt: GSI number.
212 * @flags: interrupt flags
213 *
214 * Returns: a valid linux IRQ number on success
215 * 0 or -EINVAL on failure
216 */
217static int pcc_map_interrupt(u32 interrupt, u32 flags)
218{
219 int trigger, polarity;
220
221 if (!interrupt)
222 return 0;
223
224 trigger = (flags & ACPI_PCCT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
225 : ACPI_LEVEL_SENSITIVE;
226
227 polarity = (flags & ACPI_PCCT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
228 : ACPI_ACTIVE_HIGH;
229
230 return acpi_register_gsi(NULL, interrupt, trigger, polarity);
231}
232
233static bool pcc_chan_plat_irq_can_be_shared(struct pcc_chan_info *pchan)
234{
235 return (pchan->plat_irq_flags & ACPI_PCCT_INTERRUPT_MODE) ==
236 ACPI_LEVEL_SENSITIVE;
237}
238
239static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan)
240{
241 u64 val;
242 int ret;
243
244 if (!pchan->cmd_complete.gas)
245 return true;
246
247 ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
248 if (ret)
249 return false;
250
251 /*
252 * Judge if the channel respond the interrupt based on the value of
253 * command complete.
254 */
255 val &= pchan->cmd_complete.status_mask;
256
257 /*
258 * If this is PCC slave subspace channel, and the command complete
259 * bit 0 indicates that Platform is sending a notification and OSPM
260 * needs to respond this interrupt to process this command.
261 */
262 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
263 return !val;
264
265 return !!val;
266}
267
268static int pcc_mbox_error_check_and_clear(struct pcc_chan_info *pchan)
269{
270 u64 val;
271 int ret;
272
273 ret = pcc_chan_reg_read(&pchan->error, &val);
274 if (ret)
275 return ret;
276
277 if (val & pchan->error.status_mask) {
278 val &= pchan->error.preserve_mask;
279 pcc_chan_reg_write(&pchan->error, val);
280 return -EIO;
281 }
282
283 return 0;
284}
285
286static void pcc_chan_acknowledge(struct pcc_chan_info *pchan)
287{
288 struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_hdr;
289
290 if (pchan->type != ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
291 return;
292
293 pcc_chan_reg_read_modify_write(&pchan->cmd_update);
294
295 pcc_hdr = pchan->chan.shmem;
296
297 /*
298 * The PCC slave subspace channel needs to set the command
299 * complete bit after processing message. If the PCC_ACK_FLAG
300 * is set, it should also ring the doorbell.
301 */
302 if (ioread32(&pcc_hdr->flags) & PCC_CMD_COMPLETION_NOTIFY)
303 pcc_chan_reg_read_modify_write(&pchan->db);
304}
305
306/**
307 * pcc_mbox_irq - PCC mailbox interrupt handler
308 * @irq: interrupt number
309 * @p: data/cookie passed from the caller to identify the channel
310 *
311 * Returns: IRQ_HANDLED if interrupt is handled or IRQ_NONE if not
312 */
313static irqreturn_t pcc_mbox_irq(int irq, void *p)
314{
315 struct pcc_chan_info *pchan;
316 struct mbox_chan *chan = p;
317
318 pchan = chan->con_priv;
319
320 if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack))
321 return IRQ_NONE;
322
323 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE &&
324 !pchan->chan_in_use)
325 return IRQ_NONE;
326
327 if (!pcc_mbox_cmd_complete_check(pchan))
328 return IRQ_NONE;
329
330 if (pcc_mbox_error_check_and_clear(pchan))
331 return IRQ_NONE;
332
333 /*
334 * Clear this flag after updating interrupt ack register and just
335 * before mbox_chan_received_data() which might call pcc_send_data()
336 * where the flag is set again to start new transfer. This is
337 * required to avoid any possible race in updatation of this flag.
338 */
339 pchan->chan_in_use = false;
340 mbox_chan_received_data(chan, NULL);
341 mbox_chan_txdone(chan, 0);
342
343 pcc_chan_acknowledge(pchan);
344
345 return IRQ_HANDLED;
346}
347
348/**
349 * pcc_mbox_request_channel - PCC clients call this function to
350 * request a pointer to their PCC subspace, from which they
351 * can get the details of communicating with the remote.
352 * @cl: Pointer to Mailbox client, so we know where to bind the
353 * Channel.
354 * @subspace_id: The PCC Subspace index as parsed in the PCC client
355 * ACPI package. This is used to lookup the array of PCC
356 * subspaces as parsed by the PCC Mailbox controller.
357 *
358 * Return: Pointer to the PCC Mailbox Channel if successful or ERR_PTR.
359 */
360struct pcc_mbox_chan *
361pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
362{
363 struct pcc_mbox_chan *pcc_mchan;
364 struct pcc_chan_info *pchan;
365 struct mbox_chan *chan;
366 int rc;
367
368 if (subspace_id < 0 || subspace_id >= pcc_chan_count)
369 return ERR_PTR(-ENOENT);
370
371 pchan = chan_info + subspace_id;
372 chan = pchan->chan.mchan;
373 if (IS_ERR(chan) || chan->cl) {
374 pr_err("Channel not found for idx: %d\n", subspace_id);
375 return ERR_PTR(-EBUSY);
376 }
377
378 pcc_mchan = &pchan->chan;
379 pcc_mchan->shmem = acpi_os_ioremap(pcc_mchan->shmem_base_addr,
380 pcc_mchan->shmem_size);
381 if (!pcc_mchan->shmem)
382 return ERR_PTR(-ENXIO);
383
384 rc = mbox_bind_client(chan, cl);
385 if (rc) {
386 iounmap(pcc_mchan->shmem);
387 pcc_mchan->shmem = NULL;
388 return ERR_PTR(rc);
389 }
390
391 return pcc_mchan;
392}
393EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
394
395/**
396 * pcc_mbox_free_channel - Clients call this to free their Channel.
397 *
398 * @pchan: Pointer to the PCC mailbox channel as returned by
399 * pcc_mbox_request_channel()
400 */
401void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan)
402{
403 struct mbox_chan *chan = pchan->mchan;
404 struct pcc_chan_info *pchan_info;
405 struct pcc_mbox_chan *pcc_mbox_chan;
406
407 if (!chan || !chan->cl)
408 return;
409 pchan_info = chan->con_priv;
410 pcc_mbox_chan = &pchan_info->chan;
411 if (pcc_mbox_chan->shmem) {
412 iounmap(pcc_mbox_chan->shmem);
413 pcc_mbox_chan->shmem = NULL;
414 }
415
416 mbox_free_channel(chan);
417}
418EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
419
420/**
421 * pcc_send_data - Called from Mailbox Controller code. Used
422 * here only to ring the channel doorbell. The PCC client
423 * specific read/write is done in the client driver in
424 * order to maintain atomicity over PCC channel once
425 * OS has control over it. See above for flow of operations.
426 * @chan: Pointer to Mailbox channel over which to send data.
427 * @data: Client specific data written over channel. Used here
428 * only for debug after PCC transaction completes.
429 *
430 * Return: Err if something failed else 0 for success.
431 */
432static int pcc_send_data(struct mbox_chan *chan, void *data)
433{
434 int ret;
435 struct pcc_chan_info *pchan = chan->con_priv;
436
437 ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update);
438 if (ret)
439 return ret;
440
441 ret = pcc_chan_reg_read_modify_write(&pchan->db);
442 if (!ret && pchan->plat_irq > 0)
443 pchan->chan_in_use = true;
444
445 return ret;
446}
447
448static bool pcc_last_tx_done(struct mbox_chan *chan)
449{
450 struct pcc_chan_info *pchan = chan->con_priv;
451
452 return pcc_mbox_cmd_complete_check(pchan);
453}
454
455/**
456 * pcc_startup - Called from Mailbox Controller code. Used here
457 * to request the interrupt.
458 * @chan: Pointer to Mailbox channel to startup.
459 *
460 * Return: Err if something failed else 0 for success.
461 */
462static int pcc_startup(struct mbox_chan *chan)
463{
464 struct pcc_chan_info *pchan = chan->con_priv;
465 unsigned long irqflags;
466 int rc;
467
468 /*
469 * Clear and acknowledge any pending interrupts on responder channel
470 * before enabling the interrupt
471 */
472 pcc_chan_acknowledge(pchan);
473
474 if (pchan->plat_irq > 0) {
475 irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ?
476 IRQF_SHARED : 0;
477 rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq,
478 irqflags, MBOX_IRQ_NAME, chan);
479 if (unlikely(rc)) {
480 dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n",
481 pchan->plat_irq);
482 return rc;
483 }
484 }
485
486 return 0;
487}
488
489/**
490 * pcc_shutdown - Called from Mailbox Controller code. Used here
491 * to free the interrupt.
492 * @chan: Pointer to Mailbox channel to shutdown.
493 */
494static void pcc_shutdown(struct mbox_chan *chan)
495{
496 struct pcc_chan_info *pchan = chan->con_priv;
497
498 if (pchan->plat_irq > 0)
499 devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan);
500}
501
502static const struct mbox_chan_ops pcc_chan_ops = {
503 .send_data = pcc_send_data,
504 .startup = pcc_startup,
505 .shutdown = pcc_shutdown,
506 .last_tx_done = pcc_last_tx_done,
507};
508
509/**
510 * parse_pcc_subspace - Count PCC subspaces defined
511 * @header: Pointer to the ACPI subtable header under the PCCT.
512 * @end: End of subtable entry.
513 *
514 * Return: If we find a PCC subspace entry of a valid type, return 0.
515 * Otherwise, return -EINVAL.
516 *
517 * This gets called for each entry in the PCC table.
518 */
519static int parse_pcc_subspace(union acpi_subtable_headers *header,
520 const unsigned long end)
521{
522 struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header;
523
524 if (ss->header.type < ACPI_PCCT_TYPE_RESERVED)
525 return 0;
526
527 return -EINVAL;
528}
529
530static int
531pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas,
532 u64 preserve_mask, u64 set_mask, u64 status_mask, char *name)
533{
534 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
535 if (!(gas->bit_width >= 8 && gas->bit_width <= 64 &&
536 is_power_of_2(gas->bit_width))) {
537 pr_err("Error: Cannot access register of %u bit width",
538 gas->bit_width);
539 return -EFAULT;
540 }
541
542 reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8);
543 if (!reg->vaddr) {
544 pr_err("Failed to ioremap PCC %s register\n", name);
545 return -ENOMEM;
546 }
547 }
548 reg->gas = gas;
549 reg->preserve_mask = preserve_mask;
550 reg->set_mask = set_mask;
551 reg->status_mask = status_mask;
552 return 0;
553}
554
555/**
556 * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register
557 *
558 * @pchan: Pointer to the PCC channel info structure.
559 * @pcct_entry: Pointer to the ACPI subtable header.
560 *
561 * Return: 0 for Success, else errno.
562 *
563 * There should be one entry per PCC channel. This gets called for each
564 * entry in the PCC table. This uses PCCY Type1 structure for all applicable
565 * types(Type 1-4) to fetch irq
566 */
567static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan,
568 struct acpi_subtable_header *pcct_entry)
569{
570 int ret = 0;
571 struct acpi_pcct_hw_reduced *pcct_ss;
572
573 if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE ||
574 pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
575 return 0;
576
577 pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry;
578 pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt,
579 (u32)pcct_ss->flags);
580 if (pchan->plat_irq <= 0) {
581 pr_err("PCC GSI %d not registered\n",
582 pcct_ss->platform_interrupt);
583 return -EINVAL;
584 }
585 pchan->plat_irq_flags = pcct_ss->flags;
586
587 if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
588 struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;
589
590 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
591 &pcct2_ss->platform_ack_register,
592 pcct2_ss->ack_preserve_mask,
593 pcct2_ss->ack_write_mask, 0,
594 "PLAT IRQ ACK");
595
596 } else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE ||
597 pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) {
598 struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss;
599
600 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
601 &pcct_ext->platform_ack_register,
602 pcct_ext->ack_preserve_mask,
603 pcct_ext->ack_set_mask, 0,
604 "PLAT IRQ ACK");
605 }
606
607 if (pcc_chan_plat_irq_can_be_shared(pchan) &&
608 !pchan->plat_irq_ack.gas) {
609 pr_err("PCC subspace has level IRQ with no ACK register\n");
610 return -EINVAL;
611 }
612
613 return ret;
614}
615
616/**
617 * pcc_parse_subspace_db_reg - Parse the PCC doorbell register
618 *
619 * @pchan: Pointer to the PCC channel info structure.
620 * @pcct_entry: Pointer to the ACPI subtable header.
621 *
622 * Return: 0 for Success, else errno.
623 */
624static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan,
625 struct acpi_subtable_header *pcct_entry)
626{
627 int ret = 0;
628
629 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
630 struct acpi_pcct_subspace *pcct_ss;
631
632 pcct_ss = (struct acpi_pcct_subspace *)pcct_entry;
633
634 ret = pcc_chan_reg_init(&pchan->db,
635 &pcct_ss->doorbell_register,
636 pcct_ss->preserve_mask,
637 pcct_ss->write_mask, 0, "Doorbell");
638
639 } else {
640 struct acpi_pcct_ext_pcc_master *pcct_ext;
641
642 pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry;
643
644 ret = pcc_chan_reg_init(&pchan->db,
645 &pcct_ext->doorbell_register,
646 pcct_ext->preserve_mask,
647 pcct_ext->write_mask, 0, "Doorbell");
648 if (ret)
649 return ret;
650
651 ret = pcc_chan_reg_init(&pchan->cmd_complete,
652 &pcct_ext->cmd_complete_register,
653 0, 0, pcct_ext->cmd_complete_mask,
654 "Command Complete Check");
655 if (ret)
656 return ret;
657
658 ret = pcc_chan_reg_init(&pchan->cmd_update,
659 &pcct_ext->cmd_update_register,
660 pcct_ext->cmd_update_preserve_mask,
661 pcct_ext->cmd_update_set_mask, 0,
662 "Command Complete Update");
663 if (ret)
664 return ret;
665
666 ret = pcc_chan_reg_init(&pchan->error,
667 &pcct_ext->error_status_register,
668 ~pcct_ext->error_status_mask, 0,
669 pcct_ext->error_status_mask,
670 "Error Status");
671 }
672 return ret;
673}
674
675/**
676 * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information
677 *
678 * @pchan: Pointer to the PCC channel info structure.
679 * @pcct_entry: Pointer to the ACPI subtable header.
680 *
681 */
682static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan,
683 struct acpi_subtable_header *pcct_entry)
684{
685 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
686 struct acpi_pcct_subspace *pcct_ss =
687 (struct acpi_pcct_subspace *)pcct_entry;
688
689 pchan->chan.shmem_base_addr = pcct_ss->base_address;
690 pchan->chan.shmem_size = pcct_ss->length;
691 pchan->chan.latency = pcct_ss->latency;
692 pchan->chan.max_access_rate = pcct_ss->max_access_rate;
693 pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time;
694 } else {
695 struct acpi_pcct_ext_pcc_master *pcct_ext =
696 (struct acpi_pcct_ext_pcc_master *)pcct_entry;
697
698 pchan->chan.shmem_base_addr = pcct_ext->base_address;
699 pchan->chan.shmem_size = pcct_ext->length;
700 pchan->chan.latency = pcct_ext->latency;
701 pchan->chan.max_access_rate = pcct_ext->max_access_rate;
702 pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time;
703 }
704}
705
706/**
707 * acpi_pcc_probe - Parse the ACPI tree for the PCCT.
708 *
709 * Return: 0 for Success, else errno.
710 */
711static int __init acpi_pcc_probe(void)
712{
713 int count, i, rc = 0;
714 acpi_status status;
715 struct acpi_table_header *pcct_tbl;
716 struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED];
717
718 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
719 if (ACPI_FAILURE(status) || !pcct_tbl)
720 return -ENODEV;
721
722 /* Set up the subtable handlers */
723 for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE;
724 i < ACPI_PCCT_TYPE_RESERVED; i++) {
725 proc[i].id = i;
726 proc[i].count = 0;
727 proc[i].handler = parse_pcc_subspace;
728 }
729
730 count = acpi_table_parse_entries_array(ACPI_SIG_PCCT,
731 sizeof(struct acpi_table_pcct), proc,
732 ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES);
733 if (count <= 0 || count > MAX_PCC_SUBSPACES) {
734 if (count < 0)
735 pr_warn("Error parsing PCC subspaces from PCCT\n");
736 else
737 pr_warn("Invalid PCCT: %d PCC subspaces\n", count);
738
739 rc = -EINVAL;
740 } else {
741 pcc_chan_count = count;
742 }
743
744 acpi_put_table(pcct_tbl);
745
746 return rc;
747}
748
749/**
750 * pcc_mbox_probe - Called when we find a match for the
751 * PCCT platform device. This is purely used to represent
752 * the PCCT as a virtual device for registering with the
753 * generic Mailbox framework.
754 *
755 * @pdev: Pointer to platform device returned when a match
756 * is found.
757 *
758 * Return: 0 for Success, else errno.
759 */
760static int pcc_mbox_probe(struct platform_device *pdev)
761{
762 struct device *dev = &pdev->dev;
763 struct mbox_controller *pcc_mbox_ctrl;
764 struct mbox_chan *pcc_mbox_channels;
765 struct acpi_table_header *pcct_tbl;
766 struct acpi_subtable_header *pcct_entry;
767 struct acpi_table_pcct *acpi_pcct_tbl;
768 acpi_status status = AE_OK;
769 int i, rc, count = pcc_chan_count;
770
771 /* Search for PCCT */
772 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
773
774 if (ACPI_FAILURE(status) || !pcct_tbl)
775 return -ENODEV;
776
777 pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels),
778 GFP_KERNEL);
779 if (!pcc_mbox_channels) {
780 rc = -ENOMEM;
781 goto err;
782 }
783
784 chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL);
785 if (!chan_info) {
786 rc = -ENOMEM;
787 goto err;
788 }
789
790 pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL);
791 if (!pcc_mbox_ctrl) {
792 rc = -ENOMEM;
793 goto err;
794 }
795
796 /* Point to the first PCC subspace entry */
797 pcct_entry = (struct acpi_subtable_header *) (
798 (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct));
799
800 acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl;
801 if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL) {
802 pcc_mbox_ctrl->txdone_irq = true;
803 pcc_mbox_ctrl->txdone_poll = false;
804 } else {
805 pcc_mbox_ctrl->txdone_irq = false;
806 pcc_mbox_ctrl->txdone_poll = true;
807 }
808
809 for (i = 0; i < count; i++) {
810 struct pcc_chan_info *pchan = chan_info + i;
811
812 pcc_mbox_channels[i].con_priv = pchan;
813 pchan->chan.mchan = &pcc_mbox_channels[i];
814
815 if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE &&
816 !pcc_mbox_ctrl->txdone_irq) {
817 pr_err("Platform Interrupt flag must be set to 1");
818 rc = -EINVAL;
819 goto err;
820 }
821
822 if (pcc_mbox_ctrl->txdone_irq) {
823 rc = pcc_parse_subspace_irq(pchan, pcct_entry);
824 if (rc < 0)
825 goto err;
826 }
827 rc = pcc_parse_subspace_db_reg(pchan, pcct_entry);
828 if (rc < 0)
829 goto err;
830
831 pcc_parse_subspace_shmem(pchan, pcct_entry);
832
833 pchan->type = pcct_entry->type;
834 pcct_entry = (struct acpi_subtable_header *)
835 ((unsigned long) pcct_entry + pcct_entry->length);
836 }
837
838 pcc_mbox_ctrl->num_chans = count;
839
840 pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl->num_chans);
841
842 pcc_mbox_ctrl->chans = pcc_mbox_channels;
843 pcc_mbox_ctrl->ops = &pcc_chan_ops;
844 pcc_mbox_ctrl->dev = dev;
845
846 pr_info("Registering PCC driver as Mailbox controller\n");
847 rc = mbox_controller_register(pcc_mbox_ctrl);
848 if (rc)
849 pr_err("Err registering PCC as Mailbox controller: %d\n", rc);
850 else
851 return 0;
852err:
853 acpi_put_table(pcct_tbl);
854 return rc;
855}
856
857static struct platform_driver pcc_mbox_driver = {
858 .probe = pcc_mbox_probe,
859 .driver = {
860 .name = "PCCT",
861 },
862};
863
864static int __init pcc_init(void)
865{
866 int ret;
867 struct platform_device *pcc_pdev;
868
869 if (acpi_disabled)
870 return -ENODEV;
871
872 /* Check if PCC support is available. */
873 ret = acpi_pcc_probe();
874
875 if (ret) {
876 pr_debug("ACPI PCC probe failed.\n");
877 return -ENODEV;
878 }
879
880 pcc_pdev = platform_create_bundle(&pcc_mbox_driver,
881 pcc_mbox_probe, NULL, 0, NULL, 0);
882
883 if (IS_ERR(pcc_pdev)) {
884 pr_debug("Err creating PCC platform bundle\n");
885 pcc_chan_count = 0;
886 return PTR_ERR(pcc_pdev);
887 }
888
889 return 0;
890}
891
892/*
893 * Make PCC init postcore so that users of this mailbox
894 * such as the ACPI Processor driver have it available
895 * at their init.
896 */
897postcore_initcall(pcc_init);