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 * @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 */
103 struct 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)
117 static struct pcc_chan_info *chan_info;
118 static int pcc_chan_count;
119
120 static 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 */
read_register(void __iomem * vaddr,u64 * val,unsigned int bit_width)130 static 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
write_register(void __iomem * vaddr,u64 val,unsigned int bit_width)148 static 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
pcc_chan_reg_read(struct pcc_chan_reg * reg,u64 * val)166 static 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
pcc_chan_reg_write(struct pcc_chan_reg * reg,u64 val)183 static 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
pcc_chan_reg_read_modify_write(struct pcc_chan_reg * reg)198 static 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 */
pcc_map_interrupt(u32 interrupt,u32 flags)221 static 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
pcc_chan_plat_irq_can_be_shared(struct pcc_chan_info * pchan)237 static 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
pcc_mbox_cmd_complete_check(struct pcc_chan_info * pchan)243 static 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
check_and_ack(struct pcc_chan_info * pchan,struct mbox_chan * chan)272 static 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 */
pcc_mbox_irq(int irq,void * p)308 static 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 */
356 struct pcc_mbox_chan *
pcc_mbox_request_channel(struct mbox_client * cl,int subspace_id)357 pcc_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 }
379 EXPORT_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 */
pcc_mbox_free_channel(struct pcc_mbox_chan * pchan)387 void 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 }
404 EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
405
pcc_mbox_ioremap(struct mbox_chan * chan)406 int 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 }
419 EXPORT_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 */
pcc_send_data(struct mbox_chan * chan,void * data)433 static 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 */
pcc_startup(struct mbox_chan * chan)456 static 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 */
pcc_shutdown(struct mbox_chan * chan)482 static 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
490 static 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 */
parse_pcc_subspace(union acpi_subtable_headers * header,const unsigned long end)506 static 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
517 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)518 pcc_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 */
pcc_parse_subspace_irq(struct pcc_chan_info * pchan,struct acpi_subtable_header * pcct_entry)554 static 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 */
pcc_parse_subspace_db_reg(struct pcc_chan_info * pchan,struct acpi_subtable_header * pcct_entry)611 static 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 */
pcc_parse_subspace_shmem(struct pcc_chan_info * pchan,struct acpi_subtable_header * pcct_entry)668 static 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 */
acpi_pcc_probe(void)697 static 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 */
pcc_mbox_probe(struct platform_device * pdev)746 static 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;
833 err:
834 acpi_put_table(pcct_tbl);
835 return rc;
836 }
837
838 static struct platform_driver pcc_mbox_driver = {
839 .probe = pcc_mbox_probe,
840 .driver = {
841 .name = "PCCT",
842 },
843 };
844
pcc_init(void)845 static 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 */
878 postcore_initcall(pcc_init);
879