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 */
75 struct 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 */
95 struct 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)
106 static struct pcc_chan_info *chan_info;
107 static 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 */
read_register(void __iomem * vaddr,u64 * val,unsigned int bit_width)117 static 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
write_register(void __iomem * vaddr,u64 val,unsigned int bit_width)135 static 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
pcc_chan_reg_read(struct pcc_chan_reg * reg,u64 * val)153 static 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
pcc_chan_reg_write(struct pcc_chan_reg * reg,u64 val)170 static 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
pcc_chan_reg_read_modify_write(struct pcc_chan_reg * reg)185 static 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 */
pcc_map_interrupt(u32 interrupt,u32 flags)208 static 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 */
pcc_mbox_irq(int irq,void * p)231 static 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 */
280 struct pcc_mbox_chan *
pcc_mbox_request_channel(struct mbox_client * cl,int subspace_id)281 pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
282 {
283 struct pcc_chan_info *pchan;
284 struct mbox_chan *chan;
285 int rc;
286
287 if (subspace_id < 0 || subspace_id >= pcc_chan_count)
288 return ERR_PTR(-ENOENT);
289
290 pchan = chan_info + subspace_id;
291 chan = pchan->chan.mchan;
292 if (IS_ERR(chan) || chan->cl) {
293 pr_err("Channel not found for idx: %d\n", subspace_id);
294 return ERR_PTR(-EBUSY);
295 }
296
297 rc = mbox_bind_client(chan, cl);
298 if (rc)
299 return ERR_PTR(rc);
300
301 return &pchan->chan;
302 }
303 EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
304
305 /**
306 * pcc_mbox_free_channel - Clients call this to free their Channel.
307 *
308 * @pchan: Pointer to the PCC mailbox channel as returned by
309 * pcc_mbox_request_channel()
310 */
pcc_mbox_free_channel(struct pcc_mbox_chan * pchan)311 void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan)
312 {
313 struct mbox_chan *chan = pchan->mchan;
314
315 if (!chan || !chan->cl)
316 return;
317
318 mbox_free_channel(chan);
319 }
320 EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
321
322 /**
323 * pcc_send_data - Called from Mailbox Controller code. Used
324 * here only to ring the channel doorbell. The PCC client
325 * specific read/write is done in the client driver in
326 * order to maintain atomicity over PCC channel once
327 * OS has control over it. See above for flow of operations.
328 * @chan: Pointer to Mailbox channel over which to send data.
329 * @data: Client specific data written over channel. Used here
330 * only for debug after PCC transaction completes.
331 *
332 * Return: Err if something failed else 0 for success.
333 */
pcc_send_data(struct mbox_chan * chan,void * data)334 static int pcc_send_data(struct mbox_chan *chan, void *data)
335 {
336 int ret;
337 struct pcc_chan_info *pchan = chan->con_priv;
338
339 ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update);
340 if (ret)
341 return ret;
342
343 return pcc_chan_reg_read_modify_write(&pchan->db);
344 }
345
346 /**
347 * pcc_startup - Called from Mailbox Controller code. Used here
348 * to request the interrupt.
349 * @chan: Pointer to Mailbox channel to startup.
350 *
351 * Return: Err if something failed else 0 for success.
352 */
pcc_startup(struct mbox_chan * chan)353 static int pcc_startup(struct mbox_chan *chan)
354 {
355 struct pcc_chan_info *pchan = chan->con_priv;
356 int rc;
357
358 if (pchan->plat_irq > 0) {
359 rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq, 0,
360 MBOX_IRQ_NAME, chan);
361 if (unlikely(rc)) {
362 dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n",
363 pchan->plat_irq);
364 return rc;
365 }
366 }
367
368 return 0;
369 }
370
371 /**
372 * pcc_shutdown - Called from Mailbox Controller code. Used here
373 * to free the interrupt.
374 * @chan: Pointer to Mailbox channel to shutdown.
375 */
pcc_shutdown(struct mbox_chan * chan)376 static void pcc_shutdown(struct mbox_chan *chan)
377 {
378 struct pcc_chan_info *pchan = chan->con_priv;
379
380 if (pchan->plat_irq > 0)
381 devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan);
382 }
383
384 static const struct mbox_chan_ops pcc_chan_ops = {
385 .send_data = pcc_send_data,
386 .startup = pcc_startup,
387 .shutdown = pcc_shutdown,
388 };
389
390 /**
391 * parse_pcc_subspace - Count PCC subspaces defined
392 * @header: Pointer to the ACPI subtable header under the PCCT.
393 * @end: End of subtable entry.
394 *
395 * Return: If we find a PCC subspace entry of a valid type, return 0.
396 * Otherwise, return -EINVAL.
397 *
398 * This gets called for each entry in the PCC table.
399 */
parse_pcc_subspace(union acpi_subtable_headers * header,const unsigned long end)400 static int parse_pcc_subspace(union acpi_subtable_headers *header,
401 const unsigned long end)
402 {
403 struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header;
404
405 if (ss->header.type < ACPI_PCCT_TYPE_RESERVED)
406 return 0;
407
408 return -EINVAL;
409 }
410
411 static int
pcc_chan_reg_init(struct pcc_chan_reg * reg,struct acpi_generic_address * gas,u64 preserve_mask,u64 set_mask,u64 status_mask,char * name)412 pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas,
413 u64 preserve_mask, u64 set_mask, u64 status_mask, char *name)
414 {
415 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
416 if (!(gas->bit_width >= 8 && gas->bit_width <= 64 &&
417 is_power_of_2(gas->bit_width))) {
418 pr_err("Error: Cannot access register of %u bit width",
419 gas->bit_width);
420 return -EFAULT;
421 }
422
423 reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8);
424 if (!reg->vaddr) {
425 pr_err("Failed to ioremap PCC %s register\n", name);
426 return -ENOMEM;
427 }
428 }
429 reg->gas = gas;
430 reg->preserve_mask = preserve_mask;
431 reg->set_mask = set_mask;
432 reg->status_mask = status_mask;
433 return 0;
434 }
435
436 /**
437 * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register
438 *
439 * @pchan: Pointer to the PCC channel info structure.
440 * @pcct_entry: Pointer to the ACPI subtable header.
441 *
442 * Return: 0 for Success, else errno.
443 *
444 * There should be one entry per PCC channel. This gets called for each
445 * entry in the PCC table. This uses PCCY Type1 structure for all applicable
446 * types(Type 1-4) to fetch irq
447 */
pcc_parse_subspace_irq(struct pcc_chan_info * pchan,struct acpi_subtable_header * pcct_entry)448 static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan,
449 struct acpi_subtable_header *pcct_entry)
450 {
451 int ret = 0;
452 struct acpi_pcct_hw_reduced *pcct_ss;
453
454 if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE ||
455 pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
456 return 0;
457
458 pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry;
459 pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt,
460 (u32)pcct_ss->flags);
461 if (pchan->plat_irq <= 0) {
462 pr_err("PCC GSI %d not registered\n",
463 pcct_ss->platform_interrupt);
464 return -EINVAL;
465 }
466
467 if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
468 struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;
469
470 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
471 &pcct2_ss->platform_ack_register,
472 pcct2_ss->ack_preserve_mask,
473 pcct2_ss->ack_write_mask, 0,
474 "PLAT IRQ ACK");
475
476 } else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE ||
477 pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) {
478 struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss;
479
480 ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
481 &pcct_ext->platform_ack_register,
482 pcct_ext->ack_preserve_mask,
483 pcct_ext->ack_set_mask, 0,
484 "PLAT IRQ ACK");
485 }
486
487 return ret;
488 }
489
490 /**
491 * pcc_parse_subspace_db_reg - Parse the PCC doorbell register
492 *
493 * @pchan: Pointer to the PCC channel info structure.
494 * @pcct_entry: Pointer to the ACPI subtable header.
495 *
496 * Return: 0 for Success, else errno.
497 */
pcc_parse_subspace_db_reg(struct pcc_chan_info * pchan,struct acpi_subtable_header * pcct_entry)498 static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan,
499 struct acpi_subtable_header *pcct_entry)
500 {
501 int ret = 0;
502
503 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
504 struct acpi_pcct_subspace *pcct_ss;
505
506 pcct_ss = (struct acpi_pcct_subspace *)pcct_entry;
507
508 ret = pcc_chan_reg_init(&pchan->db,
509 &pcct_ss->doorbell_register,
510 pcct_ss->preserve_mask,
511 pcct_ss->write_mask, 0, "Doorbell");
512
513 } else {
514 struct acpi_pcct_ext_pcc_master *pcct_ext;
515
516 pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry;
517
518 ret = pcc_chan_reg_init(&pchan->db,
519 &pcct_ext->doorbell_register,
520 pcct_ext->preserve_mask,
521 pcct_ext->write_mask, 0, "Doorbell");
522 if (ret)
523 return ret;
524
525 ret = pcc_chan_reg_init(&pchan->cmd_complete,
526 &pcct_ext->cmd_complete_register,
527 0, 0, pcct_ext->cmd_complete_mask,
528 "Command Complete Check");
529 if (ret)
530 return ret;
531
532 ret = pcc_chan_reg_init(&pchan->cmd_update,
533 &pcct_ext->cmd_update_register,
534 pcct_ext->cmd_update_preserve_mask,
535 pcct_ext->cmd_update_set_mask, 0,
536 "Command Complete Update");
537 if (ret)
538 return ret;
539
540 ret = pcc_chan_reg_init(&pchan->error,
541 &pcct_ext->error_status_register,
542 0, 0, pcct_ext->error_status_mask,
543 "Error Status");
544 }
545 return ret;
546 }
547
548 /**
549 * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information
550 *
551 * @pchan: Pointer to the PCC channel info structure.
552 * @pcct_entry: Pointer to the ACPI subtable header.
553 *
554 */
pcc_parse_subspace_shmem(struct pcc_chan_info * pchan,struct acpi_subtable_header * pcct_entry)555 static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan,
556 struct acpi_subtable_header *pcct_entry)
557 {
558 if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
559 struct acpi_pcct_subspace *pcct_ss =
560 (struct acpi_pcct_subspace *)pcct_entry;
561
562 pchan->chan.shmem_base_addr = pcct_ss->base_address;
563 pchan->chan.shmem_size = pcct_ss->length;
564 pchan->chan.latency = pcct_ss->latency;
565 pchan->chan.max_access_rate = pcct_ss->max_access_rate;
566 pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time;
567 } else {
568 struct acpi_pcct_ext_pcc_master *pcct_ext =
569 (struct acpi_pcct_ext_pcc_master *)pcct_entry;
570
571 pchan->chan.shmem_base_addr = pcct_ext->base_address;
572 pchan->chan.shmem_size = pcct_ext->length;
573 pchan->chan.latency = pcct_ext->latency;
574 pchan->chan.max_access_rate = pcct_ext->max_access_rate;
575 pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time;
576 }
577 }
578
579 /**
580 * acpi_pcc_probe - Parse the ACPI tree for the PCCT.
581 *
582 * Return: 0 for Success, else errno.
583 */
acpi_pcc_probe(void)584 static int __init acpi_pcc_probe(void)
585 {
586 int count, i, rc = 0;
587 acpi_status status;
588 struct acpi_table_header *pcct_tbl;
589 struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED];
590
591 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
592 if (ACPI_FAILURE(status) || !pcct_tbl)
593 return -ENODEV;
594
595 /* Set up the subtable handlers */
596 for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE;
597 i < ACPI_PCCT_TYPE_RESERVED; i++) {
598 proc[i].id = i;
599 proc[i].count = 0;
600 proc[i].handler = parse_pcc_subspace;
601 }
602
603 count = acpi_table_parse_entries_array(ACPI_SIG_PCCT,
604 sizeof(struct acpi_table_pcct), proc,
605 ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES);
606 if (count <= 0 || count > MAX_PCC_SUBSPACES) {
607 if (count < 0)
608 pr_warn("Error parsing PCC subspaces from PCCT\n");
609 else
610 pr_warn("Invalid PCCT: %d PCC subspaces\n", count);
611
612 rc = -EINVAL;
613 } else {
614 pcc_chan_count = count;
615 }
616
617 acpi_put_table(pcct_tbl);
618
619 return rc;
620 }
621
622 /**
623 * pcc_mbox_probe - Called when we find a match for the
624 * PCCT platform device. This is purely used to represent
625 * the PCCT as a virtual device for registering with the
626 * generic Mailbox framework.
627 *
628 * @pdev: Pointer to platform device returned when a match
629 * is found.
630 *
631 * Return: 0 for Success, else errno.
632 */
pcc_mbox_probe(struct platform_device * pdev)633 static int pcc_mbox_probe(struct platform_device *pdev)
634 {
635 struct device *dev = &pdev->dev;
636 struct mbox_controller *pcc_mbox_ctrl;
637 struct mbox_chan *pcc_mbox_channels;
638 struct acpi_table_header *pcct_tbl;
639 struct acpi_subtable_header *pcct_entry;
640 struct acpi_table_pcct *acpi_pcct_tbl;
641 acpi_status status = AE_OK;
642 int i, rc, count = pcc_chan_count;
643
644 /* Search for PCCT */
645 status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
646
647 if (ACPI_FAILURE(status) || !pcct_tbl)
648 return -ENODEV;
649
650 pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels),
651 GFP_KERNEL);
652 if (!pcc_mbox_channels) {
653 rc = -ENOMEM;
654 goto err;
655 }
656
657 chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL);
658 if (!chan_info) {
659 rc = -ENOMEM;
660 goto err;
661 }
662
663 pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL);
664 if (!pcc_mbox_ctrl) {
665 rc = -ENOMEM;
666 goto err;
667 }
668
669 /* Point to the first PCC subspace entry */
670 pcct_entry = (struct acpi_subtable_header *) (
671 (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct));
672
673 acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl;
674 if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL)
675 pcc_mbox_ctrl->txdone_irq = true;
676
677 for (i = 0; i < count; i++) {
678 struct pcc_chan_info *pchan = chan_info + i;
679
680 pcc_mbox_channels[i].con_priv = pchan;
681 pchan->chan.mchan = &pcc_mbox_channels[i];
682
683 if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE &&
684 !pcc_mbox_ctrl->txdone_irq) {
685 pr_err("Platform Interrupt flag must be set to 1");
686 rc = -EINVAL;
687 goto err;
688 }
689
690 if (pcc_mbox_ctrl->txdone_irq) {
691 rc = pcc_parse_subspace_irq(pchan, pcct_entry);
692 if (rc < 0)
693 goto err;
694 }
695 rc = pcc_parse_subspace_db_reg(pchan, pcct_entry);
696 if (rc < 0)
697 goto err;
698
699 pcc_parse_subspace_shmem(pchan, pcct_entry);
700
701 pcct_entry = (struct acpi_subtable_header *)
702 ((unsigned long) pcct_entry + pcct_entry->length);
703 }
704
705 pcc_mbox_ctrl->num_chans = count;
706
707 pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl->num_chans);
708
709 pcc_mbox_ctrl->chans = pcc_mbox_channels;
710 pcc_mbox_ctrl->ops = &pcc_chan_ops;
711 pcc_mbox_ctrl->dev = dev;
712
713 pr_info("Registering PCC driver as Mailbox controller\n");
714 rc = mbox_controller_register(pcc_mbox_ctrl);
715 if (rc)
716 pr_err("Err registering PCC as Mailbox controller: %d\n", rc);
717 else
718 return 0;
719 err:
720 acpi_put_table(pcct_tbl);
721 return rc;
722 }
723
724 static struct platform_driver pcc_mbox_driver = {
725 .probe = pcc_mbox_probe,
726 .driver = {
727 .name = "PCCT",
728 },
729 };
730
pcc_init(void)731 static int __init pcc_init(void)
732 {
733 int ret;
734 struct platform_device *pcc_pdev;
735
736 if (acpi_disabled)
737 return -ENODEV;
738
739 /* Check if PCC support is available. */
740 ret = acpi_pcc_probe();
741
742 if (ret) {
743 pr_debug("ACPI PCC probe failed.\n");
744 return -ENODEV;
745 }
746
747 pcc_pdev = platform_create_bundle(&pcc_mbox_driver,
748 pcc_mbox_probe, NULL, 0, NULL, 0);
749
750 if (IS_ERR(pcc_pdev)) {
751 pr_debug("Err creating PCC platform bundle\n");
752 pcc_chan_count = 0;
753 return PTR_ERR(pcc_pdev);
754 }
755
756 return 0;
757 }
758
759 /*
760 * Make PCC init postcore so that users of this mailbox
761 * such as the ACPI Processor driver have it available
762 * at their init.
763 */
764 postcore_initcall(pcc_init);
765