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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2014 Linaro Ltd.
4 * Author: Ashwin Chaugule <[email protected]>
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: lockless flag used by type 3 initiator subspaces to filter
95 * platform interrupts. Only one transfer can occur at a time, but
96 * the interrupt handler may sample the flag on another CPU, so all
97 * accesses must use READ_ONCE() or WRITE_ONCE(). Other subspace
98 * types do not test it.
99 */
100struct pcc_chan_info {
101 struct pcc_mbox_chan chan;
102 struct pcc_chan_reg db;
103 struct pcc_chan_reg plat_irq_ack;
104 struct pcc_chan_reg cmd_complete;
105 struct pcc_chan_reg cmd_update;
106 struct pcc_chan_reg error;
107 int plat_irq;
108 u8 type;
109 unsigned int plat_irq_flags;
110 bool chan_in_use;
111};
112
113#define to_pcc_chan_info(c) container_of(c, struct pcc_chan_info, chan)
114static struct pcc_chan_info *chan_info;
115static int pcc_chan_count;
116
117/*
118 * PCC can be used with perf critical drivers such as CPPC
119 * So it makes sense to locally cache the virtual address and
120 * use it to read/write to PCC registers such as doorbell register
121 *
122 * The below read_register and write_registers are used to read and
123 * write from perf critical registers such as PCC doorbell register
124 */
125static void read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
126{
127 switch (bit_width) {
128 case 8:
129 *val = readb(vaddr);
130 break;
131 case 16:
132 *val = readw(vaddr);
133 break;
134 case 32:
135 *val = readl(vaddr);
136 break;
137 case 64:
138 *val = readq(vaddr);
139 break;
140 }
141}
142
143static void write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
144{
145 switch (bit_width) {
146 case 8:
147 writeb(val, vaddr);
148 break;
149 case 16:
150 writew(val, vaddr);
151 break;
152 case 32:
153 writel(val, vaddr);
154 break;
155 case 64:
156 writeq(val, vaddr);
157 break;
158 }
159}
160
161static int pcc_chan_reg_read(struct pcc_chan_reg *reg, u64 *val)
162{
163 int ret = 0;
164
165 if (!reg->gas) {
166 *val = 0;
167 return 0;
168 }
169
170 if (reg->vaddr)
171 read_register(reg->vaddr, val, reg->gas->bit_width);
172 else
173 ret = acpi_read(val, reg->gas);
174
175 return ret;
176}
177
178static int pcc_chan_reg_write(struct pcc_chan_reg *reg, u64 val)
179{
180 int ret = 0;
181
182 if (!reg->gas)
183 return 0;
184
185 if (reg->vaddr)
186 write_register(reg->vaddr, val, reg->gas->bit_width);
187 else
188 ret = acpi_write(val, reg->gas);
189
190 return ret;
191}
192
193static int pcc_chan_reg_read_modify_write(struct pcc_chan_reg *reg)
194{
195 int ret = 0;
196 u64 val;
197
198 ret = pcc_chan_reg_read(reg, &val);
199 if (ret)
200 return ret;
201
202 val &= reg->preserve_mask;
203 val |= reg->set_mask;
204
205 return pcc_chan_reg_write(reg, val);
206}
207
208/**
209 * pcc_map_interrupt - Map a PCC subspace GSI to a linux IRQ number
210 * @interrupt: GSI number.
211 * @flags: interrupt flags
212 *
213 * Returns: a valid linux IRQ number on success
214 * 0 or -EINVAL on failure
215 */
216static int pcc_map_interrupt(u32 interrupt, u32 flags)
217{
218 int trigger, polarity;
219
220 if (!interrupt)
221 return 0;
222
223 trigger = (flags & ACPI_PCCT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
224 : ACPI_LEVEL_SENSITIVE;
225
226 polarity = (flags & ACPI_PCCT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
227 : ACPI_ACTIVE_HIGH;
228
229 return acpi_register_gsi(NULL, interrupt, trigger, polarity);
230}
231
232static bool pcc_chan_plat_irq_can_be_shared(struct pcc_chan_info *pchan)
233{
234 return (pchan->plat_irq_flags & ACPI_PCCT_INTERRUPT_MODE) ==
235 ACPI_LEVEL_SENSITIVE;
236}
237
238static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan)
239{
240 u64 val;
241 int ret;
242
243 if (!pchan->cmd_complete.gas)
244 return true;
245
246 ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
247 if (ret)
248 return false;
249
250 /*
251 * Judge if the channel respond the interrupt based on the value of
252 * command complete.
253 */
254 val &= pchan->cmd_complete.status_mask;
255
256 /*
257 * If this is PCC slave subspace channel, and the command complete
258 * bit 0 indicates that Platform is sending a notification and OSPM
259 * needs to respond this interrupt to process this command.
260 */
261 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
262 return !val;
263
264 return !!val;
265}
266
267static int pcc_mbox_error_check_and_clear(struct pcc_chan_info *pchan)
268{
269 u64 val;
270 int ret;
271
272 ret = pcc_chan_reg_read(&pchan->error, &val);
273 if (ret)
274 return ret;
275
276 if (val & pchan->error.status_mask) {
277 val &= pchan->error.preserve_mask;
278 pcc_chan_reg_write(&pchan->error, val);
279 return -EIO;
280 }
281
282 return 0;
283}
284
285static void pcc_chan_acknowledge(struct pcc_chan_info *pchan)
286{
287 struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_hdr;
288
289 if (pchan->type != ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
290 return;
291
292 pcc_chan_reg_read_modify_write(&pchan->cmd_update);
293
294 pcc_hdr = pchan->chan.shmem;
295
296 /*
297 * The PCC slave subspace channel needs to set the command
298 * complete bit after processing message. If the PCC_ACK_FLAG
299 * is set, it should also ring the doorbell.
300 */
301 if (ioread32(&pcc_hdr->flags) & PCC_CMD_COMPLETION_NOTIFY)
302 pcc_chan_reg_read_modify_write(&pchan->db);
303}
304
305/**
306 * pcc_mbox_irq - PCC mailbox interrupt handler
307 * @irq: interrupt number
308 * @p: data/cookie passed from the caller to identify the channel
309 *
310 * Returns: IRQ_HANDLED if interrupt is handled or IRQ_NONE if not
311 */
312static irqreturn_t pcc_mbox_irq(int irq, void *p)
313{
314 struct pcc_chan_info *pchan;
315 struct mbox_chan *chan = p;
316
317 pchan = chan->con_priv;
318
319 if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack))
320 return IRQ_NONE;
321
322 /*
323 * Initiator subspaces use this flag to filter shared interrupts. Use
324 * READ_ONCE() to sample the lockless flag written by pcc_send_data()
325 * on another CPU.
326 */
327 if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE &&
328 !READ_ONCE(pchan->chan_in_use))
329 return IRQ_NONE;
330
331 if (!pcc_mbox_cmd_complete_check(pchan))
332 return IRQ_NONE;
333
334 if (pcc_mbox_error_check_and_clear(pchan))
335 return IRQ_NONE;
336
337 /*
338 * Clear this flag after updating the interrupt ack register and before
339 * notifying the client and mailbox core. mbox_chan_txdone() may submit
340 * the next queued transfer and set the flag again. Use WRITE_ONCE() for
341 * the lockless update observed by the send and interrupt paths.
342 */
343 WRITE_ONCE(pchan->chan_in_use, false);
344 mbox_chan_received_data(chan, NULL);
345 mbox_chan_txdone(chan, 0);
346
347 pcc_chan_acknowledge(pchan);
348
349 return IRQ_HANDLED;
350}
351
352static int pcc_mbox_validate_signature(struct pcc_mbox_chan *pcc_mchan,
353 int subspace_id)
354{
355 u32 expected_signature = PCC_SIGNATURE | subspace_id;
356 u32 signature;
357
358 if (pcc_mchan->shmem_size < sizeof(signature)) {
359 pr_err("PCC subspace %d shared memory is too small\n",
360 subspace_id);
361 return -EINVAL;
362 }
363
364 signature = ioread32(pcc_mchan->shmem);
365 if (signature != expected_signature)
366 pr_warn("PCC subspace %d invalid signature %#x expected %#x\n",
367 subspace_id, signature, expected_signature);
368
369 return 0;
370}
371
372/**
373 * pcc_mbox_request_channel - PCC clients call this function to
374 * request a pointer to their PCC subspace, from which they
375 * can get the details of communicating with the remote.
376 * @cl: Pointer to Mailbox client, so we know where to bind the
377 * Channel.
378 * @subspace_id: The PCC Subspace index as parsed in the PCC client
379 * ACPI package. This is used to lookup the array of PCC
380 * subspaces as parsed by the PCC Mailbox controller.
381 *
382 * Return: Pointer to the PCC Mailbox Channel if successful or ERR_PTR.
383 */
384struct pcc_mbox_chan *
385pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
386{
387 struct pcc_mbox_chan *pcc_mchan;
388 struct pcc_chan_info *pchan;
389 struct mbox_chan *chan;
390 int rc;
391
392 if (subspace_id < 0 || subspace_id >= pcc_chan_count)
393 return ERR_PTR(-ENOENT);
394
395 pchan = chan_info + subspace_id;
396 chan = pchan->chan.mchan;
397 if (IS_ERR(chan) || chan->cl) {
398 pr_err("Channel not found for idx: %d\n", subspace_id);
399 return ERR_PTR(-EBUSY);
400 }
401
402 pcc_mchan = &pchan->chan;
403 pcc_mchan->shmem = acpi_os_ioremap(pcc_mchan->shmem_base_addr,
404 pcc_mchan->shmem_size);
405 if (!pcc_mchan->shmem)
406 return ERR_PTR(-ENXIO);
407
408 rc = pcc_mbox_validate_signature(pcc_mchan, subspace_id);
409 if (rc)
410 goto err_unmap_shmem;
411
412 rc = mbox_bind_client(chan, cl);
413 if (rc)
414 goto err_unmap_shmem;
415
416 return pcc_mchan;
417
418err_unmap_shmem:
419 iounmap(pcc_mchan->shmem);
420 pcc_mchan->shmem = NULL;
421 return ERR_PTR(rc);
422}
423EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
424
425/**
426 * pcc_mbox_free_channel - Clients call this to free their Channel.
427 *
428 * @pchan: Pointer to the PCC mailbox channel as returned by
429 * pcc_mbox_request_channel()
430 */
431void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan)
432{
433 struct mbox_chan *chan = pchan->mchan;
434 struct pcc_chan_info *pchan_info;
435 struct pcc_mbox_chan *pcc_mbox_chan;
436
437 if (!chan || !chan->cl)
438 return;
439 pchan_info = chan->con_priv;
440 pcc_mbox_chan = &pchan_info->chan;
441 if (pcc_mbox_chan->shmem) {
442 iounmap(pcc_mbox_chan->shmem);
443 pcc_mbox_chan->shmem = NULL;
444 }
445
446 mbox_free_channel(chan);
447}
448EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
449
450/**
451 * pcc_send_data - Called from Mailbox Controller code. Used
452 * here only to ring the channel doorbell. The PCC client
453 * specific read/write is done in the client driver in
454 * order to maintain atomicity over PCC channel once
455 * OS has control over it. See above for flow of operations.
456 * @chan: Pointer to Mailbox channel over which to send data.
457 * @data: Client specific data written over channel. Used here
458 * only for debug after PCC transaction completes.
459 *
460 * Return: Err if something failed else 0 for success.
461 */
462static int pcc_send_data(struct mbox_chan *chan, void *data)
463{
464 int ret;
465 struct pcc_chan_info *pchan = chan->con_priv;
466
467 ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update);
468 if (ret)
469 return ret;
470
471 /*
472 * Set chan_in_use before ringing the doorbell so a fast completion
473 * interrupt is not mistaken for a shared interrupt from another
474 * subspace. Use WRITE_ONCE() for the lockless flag update. The
475 * ordered I/O accessor used to ring the doorbell orders this store
476 * before the platform is notified.
477 */
478 if (pchan->plat_irq > 0)
479 WRITE_ONCE(pchan->chan_in_use, true);
480 ret = pcc_chan_reg_read_modify_write(&pchan->db);
481 if (ret && pchan->plat_irq > 0)
482 WRITE_ONCE(pchan->chan_in_use, false);
483
484 return ret;
485}
486
487static bool pcc_last_tx_done(struct mbox_chan *chan)
488{
489 struct pcc_chan_info *pchan = chan->con_priv;
490
491 if (!(chan->txdone_method & MBOX_TXDONE_BY_POLL))
492 return false;
493
494 if (!pcc_mbox_cmd_complete_check(pchan))
495 return false;
496
497 mbox_chan_received_data(chan, NULL);
498
499 return true;
500}
501
502/**
503 * pcc_startup - Called from Mailbox Controller code. Used here
504 * to request the interrupt.
505 * @chan: Pointer to Mailbox channel to startup.
506 *
507 * Return: Err if something failed else 0 for success.
508 */
509static int pcc_startup(struct mbox_chan *chan)
510{
511 struct pcc_chan_info *pchan = chan->con_priv;
512 unsigned long irqflags;
513 int rc;
514
515 /*
516 * Clear and acknowledge any pending interrupts on responder channel
517 * before enabling the interrupt
518 */
519 pcc_chan_acknowledge(pchan);
520
521 if (pchan->plat_irq > 0) {
522 irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ?
523 IRQF_SHARED : 0;
524 rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq,
525 irqflags, MBOX_IRQ_NAME, chan);
526 if (unlikely(rc)) {
527 dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n",
528 pchan->plat_irq);
529 return rc;
530 }
531 }
532
533 return 0;
534}
535
536/**
537 * pcc_shutdown - Called from Mailbox Controller code. Used here
538 * to free the interrupt.
539 * @chan: Pointer to Mailbox channel to shutdown.
540 */
541static void pcc_shutdown(struct mbox_chan *chan)
542{
543 struct pcc_chan_info *pchan = chan->con_priv;
544
545 if (pchan->plat_irq > 0)
546 devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan);
547}
548
549static const struct mbox_chan_ops pcc_chan_ops = {
550 .send_data = pcc_send_data,
551 .startup = pcc_startup,
552 .shutdown = pcc_shutdown,
553 .last_tx_done = pcc_last_tx_done,
554};
555
556/**
557 * parse_pcc_subspace - Count PCC subspaces defined
558 * @header: Pointer to the ACPI subtable header under the PCCT.
559 * @end: End of subtable entry.
560 *
561 * Return: If we find a PCC subspace entry of a valid type, return 0.
562 * Otherwise, return -EINVAL.
563 *
564 * This gets called for each entry in the PCC table.
565 */
566static int parse_pcc_subspace(union acpi_subtable_headers *header,
567 const unsigned long end)
568{
569 struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header;
570
571 if (ss->header.type < ACPI_PCCT_TYPE_RESERVED)
572 return 0;
573
574 return -EINVAL;
575}
576
577static int
578pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas,
579 u64 preserve_mask, u64 set_mask, u64 status_mask, char *name)
580{
581 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
582 if (!(gas->bit_width >= 8 && gas->bit_width <= 64 &&
583 is_power_of_2(gas->bit_width))) {
584 pr_err("Error: Cannot access register of %u bit width",
585 gas->bit_width);
586 return -EFAULT;
587 }
588
589 reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8);
590 if (!reg->vaddr) {
591 pr_err("Failed to ioremap PCC %s register\n", name);
592 return -ENOMEM;
593 }
594 }
595 reg->gas = gas;
596 reg->preserve_mask = preserve_mask;
597 reg->set_mask = set_mask;
598 reg->status_mask = status_mask;
599 return 0;
600}
601
602/**
603 * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register
604 *
605 * @pchan: Pointer to the PCC channel info structure.
606 * @pcct_entry: Pointer to the ACPI subtable header.
607 *
608 * Return: 0 for Success, else errno.
609 *
610 * There should be one entry per PCC channel. This gets called for each
611 * entry in the PCC table. This uses PCCY Type1 structure for all applicable
612 * types(Type 1-4) to fetch irq
613 */
614static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan,
615 struct acpi_subtable_header *pcct_entry)
616{
617 int ret = 0;
618 struct acpi_pcct_hw_reduced *pcct_ss;
619
620 if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE ||
621 pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
622 return 0;
623
624 pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry;
625 pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt,
626 (u32)pcct_ss->flags);
627 if (pchan->plat_irq <= 0) {
628 pr_err("PCC GSI %d not registered\n",
629 pcct_ss->platform_interrupt);
630 return -EINVAL;
631 }
632 pchan->plat_irq_flags = pcct_ss->flags;
633
634 if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
635 struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;
636
637 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
638 &pcct2_ss->platform_ack_register,
639 pcct2_ss->ack_preserve_mask,
640 pcct2_ss->ack_write_mask, 0,
641 "PLAT IRQ ACK");
642
643 } else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE ||
644 pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) {
645 struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss;
646
647 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
648 &pcct_ext->platform_ack_register,
649 pcct_ext->ack_preserve_mask,
650 pcct_ext->ack_set_mask, 0,
651 "PLAT IRQ ACK");
652 }
653
654 if (pcc_chan_plat_irq_can_be_shared(pchan) &&
655 !pchan->plat_irq_ack.gas) {
656 pr_err("PCC subspace has level IRQ with no ACK register\n");
657 return -EINVAL;
658 }
659
660 return ret;
661}
662
663/**
664 * pcc_parse_subspace_db_reg - Parse the PCC doorbell register
665 *
666 * @pchan: Pointer to the PCC channel info structure.
667 * @pcct_entry: Pointer to the ACPI subtable header.
668 *
669 * Return: 0 for Success, else errno.
670 */
671static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan,
672 struct acpi_subtable_header *pcct_entry)
673{
674 int ret = 0;
675
676 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
677 struct acpi_pcct_subspace *pcct_ss;
678
679 pcct_ss = (struct acpi_pcct_subspace *)pcct_entry;
680
681 ret = pcc_chan_reg_init(&pchan->db,
682 &pcct_ss->doorbell_register,
683 pcct_ss->preserve_mask,
684 pcct_ss->write_mask, 0, "Doorbell");
685
686 } else {
687 struct acpi_pcct_ext_pcc_master *pcct_ext;
688
689 pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry;
690
691 ret = pcc_chan_reg_init(&pchan->db,
692 &pcct_ext->doorbell_register,
693 pcct_ext->preserve_mask,
694 pcct_ext->write_mask, 0, "Doorbell");
695 if (ret)
696 return ret;
697
698 ret = pcc_chan_reg_init(&pchan->cmd_complete,
699 &pcct_ext->cmd_complete_register,
700 0, 0, pcct_ext->cmd_complete_mask,
701 "Command Complete Check");
702 if (ret)
703 return ret;
704
705 ret = pcc_chan_reg_init(&pchan->cmd_update,
706 &pcct_ext->cmd_update_register,
707 pcct_ext->cmd_update_preserve_mask,
708 pcct_ext->cmd_update_set_mask, 0,
709 "Command Complete Update");
710 if (ret)
711 return ret;
712
713 ret = pcc_chan_reg_init(&pchan->error,
714 &pcct_ext->error_status_register,
715 ~pcct_ext->error_status_mask, 0,
716 pcct_ext->error_status_mask,
717 "Error Status");
718 }
719 return ret;
720}
721
722/**
723 * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information
724 *
725 * @pchan: Pointer to the PCC channel info structure.
726 * @pcct_entry: Pointer to the ACPI subtable header.
727 *
728 */
729static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan,
730 struct acpi_subtable_header *pcct_entry)
731{
732 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
733 struct acpi_pcct_subspace *pcct_ss =
734 (struct acpi_pcct_subspace *)pcct_entry;
735
736 pchan->chan.shmem_base_addr = pcct_ss->base_address;
737 pchan->chan.shmem_size = pcct_ss->length;
738 pchan->chan.latency = pcct_ss->latency;
739 pchan->chan.max_access_rate = pcct_ss->max_access_rate;
740 pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time;
741 } else {
742 struct acpi_pcct_ext_pcc_master *pcct_ext =
743 (struct acpi_pcct_ext_pcc_master *)pcct_entry;
744
745 pchan->chan.shmem_base_addr = pcct_ext->base_address;
746 pchan->chan.shmem_size = pcct_ext->length;
747 pchan->chan.latency = pcct_ext->latency;
748 pchan->chan.max_access_rate = pcct_ext->max_access_rate;
749 pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time;
750 }
751}
752
753/**
754 * acpi_pcc_probe - Parse the ACPI tree for the PCCT.
755 *
756 * Return: 0 for Success, else errno.
757 */
758static int __init acpi_pcc_probe(void)
759{
760 int count, i, rc = 0;
761 acpi_status status;
762 struct acpi_table_header *pcct_tbl;
763 struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED];
764
765 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
766 if (ACPI_FAILURE(status) || !pcct_tbl)
767 return -ENODEV;
768
769 /* Set up the subtable handlers */
770 for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE;
771 i < ACPI_PCCT_TYPE_RESERVED; i++) {
772 proc[i].id = i;
773 proc[i].count = 0;
774 proc[i].handler = parse_pcc_subspace;
775 }
776
777 count = acpi_table_parse_entries_array(ACPI_SIG_PCCT,
778 sizeof(struct acpi_table_pcct), proc,
779 ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES);
780 if (count <= 0 || count > MAX_PCC_SUBSPACES) {
781 if (count < 0)
782 pr_warn("Error parsing PCC subspaces from PCCT\n");
783 else
784 pr_warn("Invalid PCCT: %d PCC subspaces\n", count);
785
786 rc = -EINVAL;
787 } else {
788 pcc_chan_count = count;
789 }
790
791 acpi_put_table(pcct_tbl);
792
793 return rc;
794}
795
796/**
797 * pcc_mbox_probe - Called when we find a match for the
798 * PCCT platform device. This is purely used to represent
799 * the PCCT as a virtual device for registering with the
800 * generic Mailbox framework.
801 *
802 * @pdev: Pointer to platform device returned when a match
803 * is found.
804 *
805 * Return: 0 for Success, else errno.
806 */
807static int pcc_mbox_probe(struct platform_device *pdev)
808{
809 struct device *dev = &pdev->dev;
810 struct mbox_controller *pcc_mbox_ctrl;
811 struct mbox_chan *pcc_mbox_channels;
812 struct acpi_table_header *pcct_tbl;
813 struct acpi_subtable_header *pcct_entry;
814 struct acpi_table_pcct *acpi_pcct_tbl;
815 acpi_status status = AE_OK;
816 int i, rc, count = pcc_chan_count;
817
818 /* Search for PCCT */
819 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
820
821 if (ACPI_FAILURE(status) || !pcct_tbl)
822 return -ENODEV;
823
824 pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels),
825 GFP_KERNEL);
826 if (!pcc_mbox_channels) {
827 rc = -ENOMEM;
828 goto err;
829 }
830
831 chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL);
832 if (!chan_info) {
833 rc = -ENOMEM;
834 goto err;
835 }
836
837 pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL);
838 if (!pcc_mbox_ctrl) {
839 rc = -ENOMEM;
840 goto err;
841 }
842
843 /* Point to the first PCC subspace entry */
844 pcct_entry = (struct acpi_subtable_header *) (
845 (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct));
846
847 acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl;
848 if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL) {
849 pcc_mbox_ctrl->txdone_irq = true;
850 pcc_mbox_ctrl->txdone_poll = false;
851 } else {
852 pcc_mbox_ctrl->txdone_irq = false;
853 pcc_mbox_ctrl->txdone_poll = true;
854 }
855
856 for (i = 0; i < count; i++) {
857 struct pcc_chan_info *pchan = chan_info + i;
858
859 pcc_mbox_channels[i].con_priv = pchan;
860 pchan->chan.mchan = &pcc_mbox_channels[i];
861
862 if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE &&
863 !pcc_mbox_ctrl->txdone_irq) {
864 pr_err("Platform Interrupt flag must be set to 1");
865 rc = -EINVAL;
866 goto err;
867 }
868
869 if (pcc_mbox_ctrl->txdone_irq) {
870 rc = pcc_parse_subspace_irq(pchan, pcct_entry);
871 if (rc < 0)
872 goto err;
873 }
874 rc = pcc_parse_subspace_db_reg(pchan, pcct_entry);
875 if (rc < 0)
876 goto err;
877
878 pcc_parse_subspace_shmem(pchan, pcct_entry);
879
880 pchan->type = pcct_entry->type;
881 pcct_entry = (struct acpi_subtable_header *)
882 ((unsigned long) pcct_entry + pcct_entry->length);
883 }
884
885 pcc_mbox_ctrl->num_chans = count;
886
887 pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl->num_chans);
888
889 pcc_mbox_ctrl->chans = pcc_mbox_channels;
890 pcc_mbox_ctrl->ops = &pcc_chan_ops;
891 pcc_mbox_ctrl->dev = dev;
892
893 pr_info("Registering PCC driver as Mailbox controller\n");
894 rc = mbox_controller_register(pcc_mbox_ctrl);
895 if (rc)
896 pr_err("Err registering PCC as Mailbox controller: %d\n", rc);
897 else
898 return 0;
899err:
900 acpi_put_table(pcct_tbl);
901 return rc;
902}
903
904static struct platform_driver pcc_mbox_driver = {
905 .probe = pcc_mbox_probe,
906 .driver = {
907 .name = "PCCT",
908 },
909};
910
911static int __init pcc_init(void)
912{
913 int ret;
914 struct platform_device *pcc_pdev;
915
916 if (acpi_disabled)
917 return -ENODEV;
918
919 /* Check if PCC support is available. */
920 ret = acpi_pcc_probe();
921
922 if (ret) {
923 pr_debug("ACPI PCC probe failed.\n");
924 return -ENODEV;
925 }
926
927 pcc_pdev = platform_create_bundle(&pcc_mbox_driver,
928 pcc_mbox_probe, NULL, 0, NULL, 0);
929
930 if (IS_ERR(pcc_pdev)) {
931 pr_debug("Err creating PCC platform bundle\n");
932 pcc_chan_count = 0;
933 return PTR_ERR(pcc_pdev);
934 }
935
936 return 0;
937}
938
939/*
940 * Make PCC init postcore so that users of this mailbox
941 * such as the ACPI Processor driver have it available
942 * at their init.
943 */
944postcore_initcall(pcc_init);