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