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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Data Object Exchange
4 * PCIe r6.0, sec 6.30 DOE
5 *
6 * Copyright (C) 2021 Huawei
7 * Jonathan Cameron <Jonathan.Cameron@huawei.com>
8 *
9 * Copyright (C) 2022 Intel Corporation
10 * Ira Weiny <ira.weiny@intel.com>
11 */
12
13#define dev_fmt(fmt) "DOE: " fmt
14
15#include <linux/bitfield.h>
16#include <linux/delay.h>
17#include <linux/jiffies.h>
18#include <linux/mutex.h>
19#include <linux/pci.h>
20#include <linux/pci-doe.h>
21#include <linux/workqueue.h>
22
23#include "pci.h"
24
25#define PCI_DOE_PROTOCOL_DISCOVERY 0
26
27/* Timeout of 1 second from 6.30.2 Operation, PCI Spec r6.0 */
28#define PCI_DOE_TIMEOUT HZ
29#define PCI_DOE_POLL_INTERVAL (PCI_DOE_TIMEOUT / 128)
30
31#define PCI_DOE_FLAG_CANCEL 0
32#define PCI_DOE_FLAG_DEAD 1
33
34/* Max data object length is 2^18 dwords */
35#define PCI_DOE_MAX_LENGTH (1 << 18)
36
37/**
38 * struct pci_doe_mb - State for a single DOE mailbox
39 *
40 * This state is used to manage a single DOE mailbox capability. All fields
41 * should be considered opaque to the consumers and the structure passed into
42 * the helpers below after being created by pci_doe_create_mb().
43 *
44 * @pdev: PCI device this mailbox belongs to
45 * @cap_offset: Capability offset
46 * @prots: Array of protocols supported (encoded as long values)
47 * @wq: Wait queue for work item
48 * @work_queue: Queue of pci_doe_work items
49 * @flags: Bit array of PCI_DOE_FLAG_* flags
50 */
51struct pci_doe_mb {
52 struct pci_dev *pdev;
53 u16 cap_offset;
54 struct xarray prots;
55
56 wait_queue_head_t wq;
57 struct workqueue_struct *work_queue;
58 unsigned long flags;
59};
60
61struct pci_doe_protocol {
62 u16 vid;
63 u8 type;
64};
65
66/**
67 * struct pci_doe_task - represents a single query/response
68 *
69 * @prot: DOE Protocol
70 * @request_pl: The request payload
71 * @request_pl_sz: Size of the request payload (bytes)
72 * @response_pl: The response payload
73 * @response_pl_sz: Size of the response payload (bytes)
74 * @rv: Return value. Length of received response or error (bytes)
75 * @complete: Called when task is complete
76 * @private: Private data for the consumer
77 * @work: Used internally by the mailbox
78 * @doe_mb: Used internally by the mailbox
79 */
80struct pci_doe_task {
81 struct pci_doe_protocol prot;
82 const __le32 *request_pl;
83 size_t request_pl_sz;
84 __le32 *response_pl;
85 size_t response_pl_sz;
86 int rv;
87 void (*complete)(struct pci_doe_task *task);
88 void *private;
89
90 /* initialized by pci_doe_submit_task() */
91 struct work_struct work;
92 struct pci_doe_mb *doe_mb;
93};
94
95static int pci_doe_wait(struct pci_doe_mb *doe_mb, unsigned long timeout)
96{
97 if (wait_event_timeout(doe_mb->wq,
98 test_bit(PCI_DOE_FLAG_CANCEL, &doe_mb->flags),
99 timeout))
100 return -EIO;
101 return 0;
102}
103
104static void pci_doe_write_ctrl(struct pci_doe_mb *doe_mb, u32 val)
105{
106 struct pci_dev *pdev = doe_mb->pdev;
107 int offset = doe_mb->cap_offset;
108
109 pci_write_config_dword(pdev, offset + PCI_DOE_CTRL, val);
110}
111
112static int pci_doe_abort(struct pci_doe_mb *doe_mb)
113{
114 struct pci_dev *pdev = doe_mb->pdev;
115 int offset = doe_mb->cap_offset;
116 unsigned long timeout_jiffies;
117
118 pci_dbg(pdev, "[%x] Issuing Abort\n", offset);
119
120 timeout_jiffies = jiffies + PCI_DOE_TIMEOUT;
121 pci_doe_write_ctrl(doe_mb, PCI_DOE_CTRL_ABORT);
122
123 do {
124 int rc;
125 u32 val;
126
127 rc = pci_doe_wait(doe_mb, PCI_DOE_POLL_INTERVAL);
128 if (rc)
129 return rc;
130 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
131
132 /* Abort success! */
133 if (!FIELD_GET(PCI_DOE_STATUS_ERROR, val) &&
134 !FIELD_GET(PCI_DOE_STATUS_BUSY, val))
135 return 0;
136
137 } while (!time_after(jiffies, timeout_jiffies));
138
139 /* Abort has timed out and the MB is dead */
140 pci_err(pdev, "[%x] ABORT timed out\n", offset);
141 return -EIO;
142}
143
144static int pci_doe_send_req(struct pci_doe_mb *doe_mb,
145 struct pci_doe_task *task)
146{
147 struct pci_dev *pdev = doe_mb->pdev;
148 int offset = doe_mb->cap_offset;
149 size_t length, remainder;
150 u32 val;
151 int i;
152
153 /*
154 * Check the DOE busy bit is not set. If it is set, this could indicate
155 * someone other than Linux (e.g. firmware) is using the mailbox. Note
156 * it is expected that firmware and OS will negotiate access rights via
157 * an, as yet to be defined, method.
158 */
159 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
160 if (FIELD_GET(PCI_DOE_STATUS_BUSY, val))
161 return -EBUSY;
162
163 if (FIELD_GET(PCI_DOE_STATUS_ERROR, val))
164 return -EIO;
165
166 /* Length is 2 DW of header + length of payload in DW */
167 length = 2 + DIV_ROUND_UP(task->request_pl_sz, sizeof(__le32));
168 if (length > PCI_DOE_MAX_LENGTH)
169 return -EIO;
170 if (length == PCI_DOE_MAX_LENGTH)
171 length = 0;
172
173 /* Write DOE Header */
174 val = FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_VID, task->prot.vid) |
175 FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, task->prot.type);
176 pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, val);
177 pci_write_config_dword(pdev, offset + PCI_DOE_WRITE,
178 FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH,
179 length));
180
181 /* Write payload */
182 for (i = 0; i < task->request_pl_sz / sizeof(__le32); i++)
183 pci_write_config_dword(pdev, offset + PCI_DOE_WRITE,
184 le32_to_cpu(task->request_pl[i]));
185
186 /* Write last payload dword */
187 remainder = task->request_pl_sz % sizeof(__le32);
188 if (remainder) {
189 val = 0;
190 memcpy(&val, &task->request_pl[i], remainder);
191 le32_to_cpus(&val);
192 pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, val);
193 }
194
195 pci_doe_write_ctrl(doe_mb, PCI_DOE_CTRL_GO);
196
197 return 0;
198}
199
200static bool pci_doe_data_obj_ready(struct pci_doe_mb *doe_mb)
201{
202 struct pci_dev *pdev = doe_mb->pdev;
203 int offset = doe_mb->cap_offset;
204 u32 val;
205
206 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
207 if (FIELD_GET(PCI_DOE_STATUS_DATA_OBJECT_READY, val))
208 return true;
209 return false;
210}
211
212static int pci_doe_recv_resp(struct pci_doe_mb *doe_mb, struct pci_doe_task *task)
213{
214 size_t length, payload_length, remainder, received;
215 struct pci_dev *pdev = doe_mb->pdev;
216 int offset = doe_mb->cap_offset;
217 int i = 0;
218 u32 val;
219
220 /* Read the first dword to get the protocol */
221 pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
222 if ((FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val) != task->prot.vid) ||
223 (FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val) != task->prot.type)) {
224 dev_err_ratelimited(&pdev->dev, "[%x] expected [VID, Protocol] = [%04x, %02x], got [%04x, %02x]\n",
225 doe_mb->cap_offset, task->prot.vid, task->prot.type,
226 FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val),
227 FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val));
228 return -EIO;
229 }
230
231 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
232 /* Read the second dword to get the length */
233 pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
234 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
235
236 length = FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH, val);
237 /* A value of 0x0 indicates max data object length */
238 if (!length)
239 length = PCI_DOE_MAX_LENGTH;
240 if (length < 2)
241 return -EIO;
242
243 /* First 2 dwords have already been read */
244 length -= 2;
245 received = task->response_pl_sz;
246 payload_length = DIV_ROUND_UP(task->response_pl_sz, sizeof(__le32));
247 remainder = task->response_pl_sz % sizeof(__le32);
248
249 /* remainder signifies number of data bytes in last payload dword */
250 if (!remainder)
251 remainder = sizeof(__le32);
252
253 if (length < payload_length) {
254 received = length * sizeof(__le32);
255 payload_length = length;
256 remainder = sizeof(__le32);
257 }
258
259 if (payload_length) {
260 /* Read all payload dwords except the last */
261 for (; i < payload_length - 1; i++) {
262 pci_read_config_dword(pdev, offset + PCI_DOE_READ,
263 &val);
264 task->response_pl[i] = cpu_to_le32(val);
265 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
266 }
267
268 /* Read last payload dword */
269 pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
270 cpu_to_le32s(&val);
271 memcpy(&task->response_pl[i], &val, remainder);
272 /* Prior to the last ack, ensure Data Object Ready */
273 if (!pci_doe_data_obj_ready(doe_mb))
274 return -EIO;
275 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
276 i++;
277 }
278
279 /* Flush excess length */
280 for (; i < length; i++) {
281 pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
282 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
283 }
284
285 /* Final error check to pick up on any since Data Object Ready */
286 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
287 if (FIELD_GET(PCI_DOE_STATUS_ERROR, val))
288 return -EIO;
289
290 return received;
291}
292
293static void signal_task_complete(struct pci_doe_task *task, int rv)
294{
295 task->rv = rv;
296 destroy_work_on_stack(&task->work);
297 task->complete(task);
298}
299
300static void signal_task_abort(struct pci_doe_task *task, int rv)
301{
302 struct pci_doe_mb *doe_mb = task->doe_mb;
303 struct pci_dev *pdev = doe_mb->pdev;
304
305 if (pci_doe_abort(doe_mb)) {
306 /*
307 * If the device can't process an abort; set the mailbox dead
308 * - no more submissions
309 */
310 pci_err(pdev, "[%x] Abort failed marking mailbox dead\n",
311 doe_mb->cap_offset);
312 set_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags);
313 }
314 signal_task_complete(task, rv);
315}
316
317static void doe_statemachine_work(struct work_struct *work)
318{
319 struct pci_doe_task *task = container_of(work, struct pci_doe_task,
320 work);
321 struct pci_doe_mb *doe_mb = task->doe_mb;
322 struct pci_dev *pdev = doe_mb->pdev;
323 int offset = doe_mb->cap_offset;
324 unsigned long timeout_jiffies;
325 u32 val;
326 int rc;
327
328 if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags)) {
329 signal_task_complete(task, -EIO);
330 return;
331 }
332
333 /* Send request */
334 rc = pci_doe_send_req(doe_mb, task);
335 if (rc) {
336 /*
337 * The specification does not provide any guidance on how to
338 * resolve conflicting requests from other entities.
339 * Furthermore, it is likely that busy will not be detected
340 * most of the time. Flag any detection of status busy with an
341 * error.
342 */
343 if (rc == -EBUSY)
344 dev_err_ratelimited(&pdev->dev, "[%x] busy detected; another entity is sending conflicting requests\n",
345 offset);
346 signal_task_abort(task, rc);
347 return;
348 }
349
350 timeout_jiffies = jiffies + PCI_DOE_TIMEOUT;
351 /* Poll for response */
352retry_resp:
353 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
354 if (FIELD_GET(PCI_DOE_STATUS_ERROR, val)) {
355 signal_task_abort(task, -EIO);
356 return;
357 }
358
359 if (!FIELD_GET(PCI_DOE_STATUS_DATA_OBJECT_READY, val)) {
360 if (time_after(jiffies, timeout_jiffies)) {
361 signal_task_abort(task, -EIO);
362 return;
363 }
364 rc = pci_doe_wait(doe_mb, PCI_DOE_POLL_INTERVAL);
365 if (rc) {
366 signal_task_abort(task, rc);
367 return;
368 }
369 goto retry_resp;
370 }
371
372 rc = pci_doe_recv_resp(doe_mb, task);
373 if (rc < 0) {
374 signal_task_abort(task, rc);
375 return;
376 }
377
378 signal_task_complete(task, rc);
379}
380
381static void pci_doe_task_complete(struct pci_doe_task *task)
382{
383 complete(task->private);
384}
385
386static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid,
387 u8 *protocol)
388{
389 u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX,
390 *index);
391 __le32 request_pl_le = cpu_to_le32(request_pl);
392 __le32 response_pl_le;
393 u32 response_pl;
394 int rc;
395
396 rc = pci_doe(doe_mb, PCI_VENDOR_ID_PCI_SIG, PCI_DOE_PROTOCOL_DISCOVERY,
397 &request_pl_le, sizeof(request_pl_le),
398 &response_pl_le, sizeof(response_pl_le));
399 if (rc < 0)
400 return rc;
401
402 if (rc != sizeof(response_pl_le))
403 return -EIO;
404
405 response_pl = le32_to_cpu(response_pl_le);
406 *vid = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID, response_pl);
407 *protocol = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL,
408 response_pl);
409 *index = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX,
410 response_pl);
411
412 return 0;
413}
414
415static void *pci_doe_xa_prot_entry(u16 vid, u8 prot)
416{
417 return xa_mk_value((vid << 8) | prot);
418}
419
420static int pci_doe_cache_protocols(struct pci_doe_mb *doe_mb)
421{
422 u8 index = 0;
423 u8 xa_idx = 0;
424
425 do {
426 int rc;
427 u16 vid;
428 u8 prot;
429
430 rc = pci_doe_discovery(doe_mb, &index, &vid, &prot);
431 if (rc)
432 return rc;
433
434 pci_dbg(doe_mb->pdev,
435 "[%x] Found protocol %d vid: %x prot: %x\n",
436 doe_mb->cap_offset, xa_idx, vid, prot);
437
438 rc = xa_insert(&doe_mb->prots, xa_idx++,
439 pci_doe_xa_prot_entry(vid, prot), GFP_KERNEL);
440 if (rc)
441 return rc;
442 } while (index);
443
444 return 0;
445}
446
447static void pci_doe_cancel_tasks(struct pci_doe_mb *doe_mb)
448{
449 /* Stop all pending work items from starting */
450 set_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags);
451
452 /* Cancel an in progress work item, if necessary */
453 set_bit(PCI_DOE_FLAG_CANCEL, &doe_mb->flags);
454 wake_up(&doe_mb->wq);
455}
456
457/**
458 * pci_doe_create_mb() - Create a DOE mailbox object
459 *
460 * @pdev: PCI device to create the DOE mailbox for
461 * @cap_offset: Offset of the DOE mailbox
462 *
463 * Create a single mailbox object to manage the mailbox protocol at the
464 * cap_offset specified.
465 *
466 * RETURNS: created mailbox object on success
467 * ERR_PTR(-errno) on failure
468 */
469static struct pci_doe_mb *pci_doe_create_mb(struct pci_dev *pdev,
470 u16 cap_offset)
471{
472 struct pci_doe_mb *doe_mb;
473 int rc;
474
475 doe_mb = kzalloc(sizeof(*doe_mb), GFP_KERNEL);
476 if (!doe_mb)
477 return ERR_PTR(-ENOMEM);
478
479 doe_mb->pdev = pdev;
480 doe_mb->cap_offset = cap_offset;
481 init_waitqueue_head(&doe_mb->wq);
482 xa_init(&doe_mb->prots);
483
484 doe_mb->work_queue = alloc_ordered_workqueue("%s %s DOE [%x]", 0,
485 dev_bus_name(&pdev->dev),
486 pci_name(pdev),
487 doe_mb->cap_offset);
488 if (!doe_mb->work_queue) {
489 pci_err(pdev, "[%x] failed to allocate work queue\n",
490 doe_mb->cap_offset);
491 rc = -ENOMEM;
492 goto err_free;
493 }
494
495 /* Reset the mailbox by issuing an abort */
496 rc = pci_doe_abort(doe_mb);
497 if (rc) {
498 pci_err(pdev, "[%x] failed to reset mailbox with abort command : %d\n",
499 doe_mb->cap_offset, rc);
500 goto err_destroy_wq;
501 }
502
503 /*
504 * The state machine and the mailbox should be in sync now;
505 * Use the mailbox to query protocols.
506 */
507 rc = pci_doe_cache_protocols(doe_mb);
508 if (rc) {
509 pci_err(pdev, "[%x] failed to cache protocols : %d\n",
510 doe_mb->cap_offset, rc);
511 goto err_cancel;
512 }
513
514 return doe_mb;
515
516err_cancel:
517 pci_doe_cancel_tasks(doe_mb);
518 xa_destroy(&doe_mb->prots);
519err_destroy_wq:
520 destroy_workqueue(doe_mb->work_queue);
521err_free:
522 kfree(doe_mb);
523 return ERR_PTR(rc);
524}
525
526/**
527 * pci_doe_destroy_mb() - Destroy a DOE mailbox object
528 *
529 * @doe_mb: DOE mailbox
530 *
531 * Destroy all internal data structures created for the DOE mailbox.
532 */
533static void pci_doe_destroy_mb(struct pci_doe_mb *doe_mb)
534{
535 pci_doe_cancel_tasks(doe_mb);
536 xa_destroy(&doe_mb->prots);
537 destroy_workqueue(doe_mb->work_queue);
538 kfree(doe_mb);
539}
540
541/**
542 * pci_doe_supports_prot() - Return if the DOE instance supports the given
543 * protocol
544 * @doe_mb: DOE mailbox capability to query
545 * @vid: Protocol Vendor ID
546 * @type: Protocol type
547 *
548 * RETURNS: True if the DOE mailbox supports the protocol specified
549 */
550static bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type)
551{
552 unsigned long index;
553 void *entry;
554
555 /* The discovery protocol must always be supported */
556 if (vid == PCI_VENDOR_ID_PCI_SIG && type == PCI_DOE_PROTOCOL_DISCOVERY)
557 return true;
558
559 xa_for_each(&doe_mb->prots, index, entry)
560 if (entry == pci_doe_xa_prot_entry(vid, type))
561 return true;
562
563 return false;
564}
565
566/**
567 * pci_doe_submit_task() - Submit a task to be processed by the state machine
568 *
569 * @doe_mb: DOE mailbox capability to submit to
570 * @task: task to be queued
571 *
572 * Submit a DOE task (request/response) to the DOE mailbox to be processed.
573 * Returns upon queueing the task object. If the queue is full this function
574 * will sleep until there is room in the queue.
575 *
576 * task->complete will be called when the state machine is done processing this
577 * task.
578 *
579 * @task must be allocated on the stack.
580 *
581 * Excess data will be discarded.
582 *
583 * RETURNS: 0 when task has been successfully queued, -ERRNO on error
584 */
585static int pci_doe_submit_task(struct pci_doe_mb *doe_mb,
586 struct pci_doe_task *task)
587{
588 if (!pci_doe_supports_prot(doe_mb, task->prot.vid, task->prot.type))
589 return -EINVAL;
590
591 if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags))
592 return -EIO;
593
594 task->doe_mb = doe_mb;
595 INIT_WORK_ONSTACK(&task->work, doe_statemachine_work);
596 queue_work(doe_mb->work_queue, &task->work);
597 return 0;
598}
599
600/**
601 * pci_doe() - Perform Data Object Exchange
602 *
603 * @doe_mb: DOE Mailbox
604 * @vendor: Vendor ID
605 * @type: Data Object Type
606 * @request: Request payload
607 * @request_sz: Size of request payload (bytes)
608 * @response: Response payload
609 * @response_sz: Size of response payload (bytes)
610 *
611 * Submit @request to @doe_mb and store the @response.
612 * The DOE exchange is performed synchronously and may therefore sleep.
613 *
614 * Payloads are treated as opaque byte streams which are transmitted verbatim,
615 * without byte-swapping. If payloads contain little-endian register values,
616 * the caller is responsible for conversion with cpu_to_le32() / le32_to_cpu().
617 *
618 * For convenience, arbitrary payload sizes are allowed even though PCIe r6.0
619 * sec 6.30.1 specifies the Data Object Header 2 "Length" in dwords. The last
620 * (partial) dword is copied with byte granularity and padded with zeroes if
621 * necessary. Callers are thus relieved of using dword-sized bounce buffers.
622 *
623 * RETURNS: Length of received response or negative errno.
624 * Received data in excess of @response_sz is discarded.
625 * The length may be smaller than @response_sz and the caller
626 * is responsible for checking that.
627 */
628int pci_doe(struct pci_doe_mb *doe_mb, u16 vendor, u8 type,
629 const void *request, size_t request_sz,
630 void *response, size_t response_sz)
631{
632 DECLARE_COMPLETION_ONSTACK(c);
633 struct pci_doe_task task = {
634 .prot.vid = vendor,
635 .prot.type = type,
636 .request_pl = request,
637 .request_pl_sz = request_sz,
638 .response_pl = response,
639 .response_pl_sz = response_sz,
640 .complete = pci_doe_task_complete,
641 .private = &c,
642 };
643 int rc;
644
645 rc = pci_doe_submit_task(doe_mb, &task);
646 if (rc)
647 return rc;
648
649 wait_for_completion(&c);
650
651 return task.rv;
652}
653EXPORT_SYMBOL_GPL(pci_doe);
654
655/**
656 * pci_find_doe_mailbox() - Find Data Object Exchange mailbox
657 *
658 * @pdev: PCI device
659 * @vendor: Vendor ID
660 * @type: Data Object Type
661 *
662 * Find first DOE mailbox of a PCI device which supports the given protocol.
663 *
664 * RETURNS: Pointer to the DOE mailbox or NULL if none was found.
665 */
666struct pci_doe_mb *pci_find_doe_mailbox(struct pci_dev *pdev, u16 vendor,
667 u8 type)
668{
669 struct pci_doe_mb *doe_mb;
670 unsigned long index;
671
672 xa_for_each(&pdev->doe_mbs, index, doe_mb)
673 if (pci_doe_supports_prot(doe_mb, vendor, type))
674 return doe_mb;
675
676 return NULL;
677}
678EXPORT_SYMBOL_GPL(pci_find_doe_mailbox);
679
680void pci_doe_init(struct pci_dev *pdev)
681{
682 struct pci_doe_mb *doe_mb;
683 u16 offset = 0;
684 int rc;
685
686 xa_init(&pdev->doe_mbs);
687
688 while ((offset = pci_find_next_ext_capability(pdev, offset,
689 PCI_EXT_CAP_ID_DOE))) {
690 doe_mb = pci_doe_create_mb(pdev, offset);
691 if (IS_ERR(doe_mb)) {
692 pci_err(pdev, "[%x] failed to create mailbox: %ld\n",
693 offset, PTR_ERR(doe_mb));
694 continue;
695 }
696
697 rc = xa_insert(&pdev->doe_mbs, offset, doe_mb, GFP_KERNEL);
698 if (rc) {
699 pci_err(pdev, "[%x] failed to insert mailbox: %d\n",
700 offset, rc);
701 pci_doe_destroy_mb(doe_mb);
702 }
703 }
704}
705
706void pci_doe_destroy(struct pci_dev *pdev)
707{
708 struct pci_doe_mb *doe_mb;
709 unsigned long index;
710
711 xa_for_each(&pdev->doe_mbs, index, doe_mb)
712 pci_doe_destroy_mb(doe_mb);
713
714 xa_destroy(&pdev->doe_mbs);
715}
716
717void pci_doe_disconnected(struct pci_dev *pdev)
718{
719 struct pci_doe_mb *doe_mb;
720 unsigned long index;
721
722 xa_for_each(&pdev->doe_mbs, index, doe_mb)
723 pci_doe_cancel_tasks(doe_mb);
724}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Data Object Exchange
4 * PCIe r6.0, sec 6.30 DOE
5 *
6 * Copyright (C) 2021 Huawei
7 * Jonathan Cameron <Jonathan.Cameron@huawei.com>
8 *
9 * Copyright (C) 2022 Intel Corporation
10 * Ira Weiny <ira.weiny@intel.com>
11 */
12
13#define dev_fmt(fmt) "DOE: " fmt
14
15#include <linux/bitfield.h>
16#include <linux/delay.h>
17#include <linux/jiffies.h>
18#include <linux/mutex.h>
19#include <linux/pci.h>
20#include <linux/pci-doe.h>
21#include <linux/workqueue.h>
22
23#include "pci.h"
24
25#define PCI_DOE_PROTOCOL_DISCOVERY 0
26
27/* Timeout of 1 second from 6.30.2 Operation, PCI Spec r6.0 */
28#define PCI_DOE_TIMEOUT HZ
29#define PCI_DOE_POLL_INTERVAL (PCI_DOE_TIMEOUT / 128)
30
31#define PCI_DOE_FLAG_CANCEL 0
32#define PCI_DOE_FLAG_DEAD 1
33
34/* Max data object length is 2^18 dwords */
35#define PCI_DOE_MAX_LENGTH (1 << 18)
36
37/**
38 * struct pci_doe_mb - State for a single DOE mailbox
39 *
40 * This state is used to manage a single DOE mailbox capability. All fields
41 * should be considered opaque to the consumers and the structure passed into
42 * the helpers below after being created by pci_doe_create_mb().
43 *
44 * @pdev: PCI device this mailbox belongs to
45 * @cap_offset: Capability offset
46 * @prots: Array of protocols supported (encoded as long values)
47 * @wq: Wait queue for work item
48 * @work_queue: Queue of pci_doe_work items
49 * @flags: Bit array of PCI_DOE_FLAG_* flags
50 */
51struct pci_doe_mb {
52 struct pci_dev *pdev;
53 u16 cap_offset;
54 struct xarray prots;
55
56 wait_queue_head_t wq;
57 struct workqueue_struct *work_queue;
58 unsigned long flags;
59};
60
61struct pci_doe_protocol {
62 u16 vid;
63 u8 type;
64};
65
66/**
67 * struct pci_doe_task - represents a single query/response
68 *
69 * @prot: DOE Protocol
70 * @request_pl: The request payload
71 * @request_pl_sz: Size of the request payload (bytes)
72 * @response_pl: The response payload
73 * @response_pl_sz: Size of the response payload (bytes)
74 * @rv: Return value. Length of received response or error (bytes)
75 * @complete: Called when task is complete
76 * @private: Private data for the consumer
77 * @work: Used internally by the mailbox
78 * @doe_mb: Used internally by the mailbox
79 */
80struct pci_doe_task {
81 struct pci_doe_protocol prot;
82 const __le32 *request_pl;
83 size_t request_pl_sz;
84 __le32 *response_pl;
85 size_t response_pl_sz;
86 int rv;
87 void (*complete)(struct pci_doe_task *task);
88 void *private;
89
90 /* initialized by pci_doe_submit_task() */
91 struct work_struct work;
92 struct pci_doe_mb *doe_mb;
93};
94
95static int pci_doe_wait(struct pci_doe_mb *doe_mb, unsigned long timeout)
96{
97 if (wait_event_timeout(doe_mb->wq,
98 test_bit(PCI_DOE_FLAG_CANCEL, &doe_mb->flags),
99 timeout))
100 return -EIO;
101 return 0;
102}
103
104static void pci_doe_write_ctrl(struct pci_doe_mb *doe_mb, u32 val)
105{
106 struct pci_dev *pdev = doe_mb->pdev;
107 int offset = doe_mb->cap_offset;
108
109 pci_write_config_dword(pdev, offset + PCI_DOE_CTRL, val);
110}
111
112static int pci_doe_abort(struct pci_doe_mb *doe_mb)
113{
114 struct pci_dev *pdev = doe_mb->pdev;
115 int offset = doe_mb->cap_offset;
116 unsigned long timeout_jiffies;
117
118 pci_dbg(pdev, "[%x] Issuing Abort\n", offset);
119
120 timeout_jiffies = jiffies + PCI_DOE_TIMEOUT;
121 pci_doe_write_ctrl(doe_mb, PCI_DOE_CTRL_ABORT);
122
123 do {
124 int rc;
125 u32 val;
126
127 rc = pci_doe_wait(doe_mb, PCI_DOE_POLL_INTERVAL);
128 if (rc)
129 return rc;
130 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
131
132 /* Abort success! */
133 if (!FIELD_GET(PCI_DOE_STATUS_ERROR, val) &&
134 !FIELD_GET(PCI_DOE_STATUS_BUSY, val))
135 return 0;
136
137 } while (!time_after(jiffies, timeout_jiffies));
138
139 /* Abort has timed out and the MB is dead */
140 pci_err(pdev, "[%x] ABORT timed out\n", offset);
141 return -EIO;
142}
143
144static int pci_doe_send_req(struct pci_doe_mb *doe_mb,
145 struct pci_doe_task *task)
146{
147 struct pci_dev *pdev = doe_mb->pdev;
148 int offset = doe_mb->cap_offset;
149 unsigned long timeout_jiffies;
150 size_t length, remainder;
151 u32 val;
152 int i;
153
154 /*
155 * Check the DOE busy bit is not set. If it is set, this could indicate
156 * someone other than Linux (e.g. firmware) is using the mailbox. Note
157 * it is expected that firmware and OS will negotiate access rights via
158 * an, as yet to be defined, method.
159 *
160 * Wait up to one PCI_DOE_TIMEOUT period to allow the prior command to
161 * finish. Otherwise, simply error out as unable to field the request.
162 *
163 * PCIe r6.2 sec 6.30.3 states no interrupt is raised when the DOE Busy
164 * bit is cleared, so polling here is our best option for the moment.
165 */
166 timeout_jiffies = jiffies + PCI_DOE_TIMEOUT;
167 do {
168 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
169 } while (FIELD_GET(PCI_DOE_STATUS_BUSY, val) &&
170 !time_after(jiffies, timeout_jiffies));
171
172 if (FIELD_GET(PCI_DOE_STATUS_BUSY, val))
173 return -EBUSY;
174
175 if (FIELD_GET(PCI_DOE_STATUS_ERROR, val))
176 return -EIO;
177
178 /* Length is 2 DW of header + length of payload in DW */
179 length = 2 + DIV_ROUND_UP(task->request_pl_sz, sizeof(__le32));
180 if (length > PCI_DOE_MAX_LENGTH)
181 return -EIO;
182 if (length == PCI_DOE_MAX_LENGTH)
183 length = 0;
184
185 /* Write DOE Header */
186 val = FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_VID, task->prot.vid) |
187 FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, task->prot.type);
188 pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, val);
189 pci_write_config_dword(pdev, offset + PCI_DOE_WRITE,
190 FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH,
191 length));
192
193 /* Write payload */
194 for (i = 0; i < task->request_pl_sz / sizeof(__le32); i++)
195 pci_write_config_dword(pdev, offset + PCI_DOE_WRITE,
196 le32_to_cpu(task->request_pl[i]));
197
198 /* Write last payload dword */
199 remainder = task->request_pl_sz % sizeof(__le32);
200 if (remainder) {
201 val = 0;
202 memcpy(&val, &task->request_pl[i], remainder);
203 le32_to_cpus(&val);
204 pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, val);
205 }
206
207 pci_doe_write_ctrl(doe_mb, PCI_DOE_CTRL_GO);
208
209 return 0;
210}
211
212static bool pci_doe_data_obj_ready(struct pci_doe_mb *doe_mb)
213{
214 struct pci_dev *pdev = doe_mb->pdev;
215 int offset = doe_mb->cap_offset;
216 u32 val;
217
218 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
219 if (FIELD_GET(PCI_DOE_STATUS_DATA_OBJECT_READY, val))
220 return true;
221 return false;
222}
223
224static int pci_doe_recv_resp(struct pci_doe_mb *doe_mb, struct pci_doe_task *task)
225{
226 size_t length, payload_length, remainder, received;
227 struct pci_dev *pdev = doe_mb->pdev;
228 int offset = doe_mb->cap_offset;
229 int i = 0;
230 u32 val;
231
232 /* Read the first dword to get the protocol */
233 pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
234 if ((FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val) != task->prot.vid) ||
235 (FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val) != task->prot.type)) {
236 dev_err_ratelimited(&pdev->dev, "[%x] expected [VID, Protocol] = [%04x, %02x], got [%04x, %02x]\n",
237 doe_mb->cap_offset, task->prot.vid, task->prot.type,
238 FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val),
239 FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val));
240 return -EIO;
241 }
242
243 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
244 /* Read the second dword to get the length */
245 pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
246 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
247
248 length = FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH, val);
249 /* A value of 0x0 indicates max data object length */
250 if (!length)
251 length = PCI_DOE_MAX_LENGTH;
252 if (length < 2)
253 return -EIO;
254
255 /* First 2 dwords have already been read */
256 length -= 2;
257 received = task->response_pl_sz;
258 payload_length = DIV_ROUND_UP(task->response_pl_sz, sizeof(__le32));
259 remainder = task->response_pl_sz % sizeof(__le32);
260
261 /* remainder signifies number of data bytes in last payload dword */
262 if (!remainder)
263 remainder = sizeof(__le32);
264
265 if (length < payload_length) {
266 received = length * sizeof(__le32);
267 payload_length = length;
268 remainder = sizeof(__le32);
269 }
270
271 if (payload_length) {
272 /* Read all payload dwords except the last */
273 for (; i < payload_length - 1; i++) {
274 pci_read_config_dword(pdev, offset + PCI_DOE_READ,
275 &val);
276 task->response_pl[i] = cpu_to_le32(val);
277 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
278 }
279
280 /* Read last payload dword */
281 pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
282 cpu_to_le32s(&val);
283 memcpy(&task->response_pl[i], &val, remainder);
284 /* Prior to the last ack, ensure Data Object Ready */
285 if (!pci_doe_data_obj_ready(doe_mb))
286 return -EIO;
287 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
288 i++;
289 }
290
291 /* Flush excess length */
292 for (; i < length; i++) {
293 pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
294 pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0);
295 }
296
297 /* Final error check to pick up on any since Data Object Ready */
298 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
299 if (FIELD_GET(PCI_DOE_STATUS_ERROR, val))
300 return -EIO;
301
302 return received;
303}
304
305static void signal_task_complete(struct pci_doe_task *task, int rv)
306{
307 task->rv = rv;
308 destroy_work_on_stack(&task->work);
309 task->complete(task);
310}
311
312static void signal_task_abort(struct pci_doe_task *task, int rv)
313{
314 struct pci_doe_mb *doe_mb = task->doe_mb;
315 struct pci_dev *pdev = doe_mb->pdev;
316
317 if (pci_doe_abort(doe_mb)) {
318 /*
319 * If the device can't process an abort; set the mailbox dead
320 * - no more submissions
321 */
322 pci_err(pdev, "[%x] Abort failed marking mailbox dead\n",
323 doe_mb->cap_offset);
324 set_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags);
325 }
326 signal_task_complete(task, rv);
327}
328
329static void doe_statemachine_work(struct work_struct *work)
330{
331 struct pci_doe_task *task = container_of(work, struct pci_doe_task,
332 work);
333 struct pci_doe_mb *doe_mb = task->doe_mb;
334 struct pci_dev *pdev = doe_mb->pdev;
335 int offset = doe_mb->cap_offset;
336 unsigned long timeout_jiffies;
337 u32 val;
338 int rc;
339
340 if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags)) {
341 signal_task_complete(task, -EIO);
342 return;
343 }
344
345 /* Send request */
346 rc = pci_doe_send_req(doe_mb, task);
347 if (rc) {
348 /*
349 * The specification does not provide any guidance on how to
350 * resolve conflicting requests from other entities.
351 * Furthermore, it is likely that busy will not be detected
352 * most of the time. Flag any detection of status busy with an
353 * error.
354 */
355 if (rc == -EBUSY)
356 dev_err_ratelimited(&pdev->dev, "[%x] busy detected; another entity is sending conflicting requests\n",
357 offset);
358 signal_task_abort(task, rc);
359 return;
360 }
361
362 timeout_jiffies = jiffies + PCI_DOE_TIMEOUT;
363 /* Poll for response */
364retry_resp:
365 pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val);
366 if (FIELD_GET(PCI_DOE_STATUS_ERROR, val)) {
367 signal_task_abort(task, -EIO);
368 return;
369 }
370
371 if (!FIELD_GET(PCI_DOE_STATUS_DATA_OBJECT_READY, val)) {
372 if (time_after(jiffies, timeout_jiffies)) {
373 signal_task_abort(task, -EIO);
374 return;
375 }
376 rc = pci_doe_wait(doe_mb, PCI_DOE_POLL_INTERVAL);
377 if (rc) {
378 signal_task_abort(task, rc);
379 return;
380 }
381 goto retry_resp;
382 }
383
384 rc = pci_doe_recv_resp(doe_mb, task);
385 if (rc < 0) {
386 signal_task_abort(task, rc);
387 return;
388 }
389
390 signal_task_complete(task, rc);
391}
392
393static void pci_doe_task_complete(struct pci_doe_task *task)
394{
395 complete(task->private);
396}
397
398static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 capver, u8 *index, u16 *vid,
399 u8 *protocol)
400{
401 u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX,
402 *index) |
403 FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_VER,
404 (capver >= 2) ? 2 : 0);
405 __le32 request_pl_le = cpu_to_le32(request_pl);
406 __le32 response_pl_le;
407 u32 response_pl;
408 int rc;
409
410 rc = pci_doe(doe_mb, PCI_VENDOR_ID_PCI_SIG, PCI_DOE_PROTOCOL_DISCOVERY,
411 &request_pl_le, sizeof(request_pl_le),
412 &response_pl_le, sizeof(response_pl_le));
413 if (rc < 0)
414 return rc;
415
416 if (rc != sizeof(response_pl_le))
417 return -EIO;
418
419 response_pl = le32_to_cpu(response_pl_le);
420 *vid = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID, response_pl);
421 *protocol = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL,
422 response_pl);
423 *index = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX,
424 response_pl);
425
426 return 0;
427}
428
429static void *pci_doe_xa_prot_entry(u16 vid, u8 prot)
430{
431 return xa_mk_value((vid << 8) | prot);
432}
433
434static int pci_doe_cache_protocols(struct pci_doe_mb *doe_mb)
435{
436 u8 index = 0;
437 u8 xa_idx = 0;
438 u32 hdr = 0;
439
440 pci_read_config_dword(doe_mb->pdev, doe_mb->cap_offset, &hdr);
441
442 do {
443 int rc;
444 u16 vid;
445 u8 prot;
446
447 rc = pci_doe_discovery(doe_mb, PCI_EXT_CAP_VER(hdr), &index,
448 &vid, &prot);
449 if (rc)
450 return rc;
451
452 pci_dbg(doe_mb->pdev,
453 "[%x] Found protocol %d vid: %x prot: %x\n",
454 doe_mb->cap_offset, xa_idx, vid, prot);
455
456 rc = xa_insert(&doe_mb->prots, xa_idx++,
457 pci_doe_xa_prot_entry(vid, prot), GFP_KERNEL);
458 if (rc)
459 return rc;
460 } while (index);
461
462 return 0;
463}
464
465static void pci_doe_cancel_tasks(struct pci_doe_mb *doe_mb)
466{
467 /* Stop all pending work items from starting */
468 set_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags);
469
470 /* Cancel an in progress work item, if necessary */
471 set_bit(PCI_DOE_FLAG_CANCEL, &doe_mb->flags);
472 wake_up(&doe_mb->wq);
473}
474
475/**
476 * pci_doe_create_mb() - Create a DOE mailbox object
477 *
478 * @pdev: PCI device to create the DOE mailbox for
479 * @cap_offset: Offset of the DOE mailbox
480 *
481 * Create a single mailbox object to manage the mailbox protocol at the
482 * cap_offset specified.
483 *
484 * RETURNS: created mailbox object on success
485 * ERR_PTR(-errno) on failure
486 */
487static struct pci_doe_mb *pci_doe_create_mb(struct pci_dev *pdev,
488 u16 cap_offset)
489{
490 struct pci_doe_mb *doe_mb;
491 int rc;
492
493 doe_mb = kzalloc(sizeof(*doe_mb), GFP_KERNEL);
494 if (!doe_mb)
495 return ERR_PTR(-ENOMEM);
496
497 doe_mb->pdev = pdev;
498 doe_mb->cap_offset = cap_offset;
499 init_waitqueue_head(&doe_mb->wq);
500 xa_init(&doe_mb->prots);
501
502 doe_mb->work_queue = alloc_ordered_workqueue("%s %s DOE [%x]", 0,
503 dev_bus_name(&pdev->dev),
504 pci_name(pdev),
505 doe_mb->cap_offset);
506 if (!doe_mb->work_queue) {
507 pci_err(pdev, "[%x] failed to allocate work queue\n",
508 doe_mb->cap_offset);
509 rc = -ENOMEM;
510 goto err_free;
511 }
512
513 /* Reset the mailbox by issuing an abort */
514 rc = pci_doe_abort(doe_mb);
515 if (rc) {
516 pci_err(pdev, "[%x] failed to reset mailbox with abort command : %d\n",
517 doe_mb->cap_offset, rc);
518 goto err_destroy_wq;
519 }
520
521 /*
522 * The state machine and the mailbox should be in sync now;
523 * Use the mailbox to query protocols.
524 */
525 rc = pci_doe_cache_protocols(doe_mb);
526 if (rc) {
527 pci_err(pdev, "[%x] failed to cache protocols : %d\n",
528 doe_mb->cap_offset, rc);
529 goto err_cancel;
530 }
531
532 return doe_mb;
533
534err_cancel:
535 pci_doe_cancel_tasks(doe_mb);
536 xa_destroy(&doe_mb->prots);
537err_destroy_wq:
538 destroy_workqueue(doe_mb->work_queue);
539err_free:
540 kfree(doe_mb);
541 return ERR_PTR(rc);
542}
543
544/**
545 * pci_doe_destroy_mb() - Destroy a DOE mailbox object
546 *
547 * @doe_mb: DOE mailbox
548 *
549 * Destroy all internal data structures created for the DOE mailbox.
550 */
551static void pci_doe_destroy_mb(struct pci_doe_mb *doe_mb)
552{
553 pci_doe_cancel_tasks(doe_mb);
554 xa_destroy(&doe_mb->prots);
555 destroy_workqueue(doe_mb->work_queue);
556 kfree(doe_mb);
557}
558
559/**
560 * pci_doe_supports_prot() - Return if the DOE instance supports the given
561 * protocol
562 * @doe_mb: DOE mailbox capability to query
563 * @vid: Protocol Vendor ID
564 * @type: Protocol type
565 *
566 * RETURNS: True if the DOE mailbox supports the protocol specified
567 */
568static bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type)
569{
570 unsigned long index;
571 void *entry;
572
573 /* The discovery protocol must always be supported */
574 if (vid == PCI_VENDOR_ID_PCI_SIG && type == PCI_DOE_PROTOCOL_DISCOVERY)
575 return true;
576
577 xa_for_each(&doe_mb->prots, index, entry)
578 if (entry == pci_doe_xa_prot_entry(vid, type))
579 return true;
580
581 return false;
582}
583
584/**
585 * pci_doe_submit_task() - Submit a task to be processed by the state machine
586 *
587 * @doe_mb: DOE mailbox capability to submit to
588 * @task: task to be queued
589 *
590 * Submit a DOE task (request/response) to the DOE mailbox to be processed.
591 * Returns upon queueing the task object. If the queue is full this function
592 * will sleep until there is room in the queue.
593 *
594 * task->complete will be called when the state machine is done processing this
595 * task.
596 *
597 * @task must be allocated on the stack.
598 *
599 * Excess data will be discarded.
600 *
601 * RETURNS: 0 when task has been successfully queued, -ERRNO on error
602 */
603static int pci_doe_submit_task(struct pci_doe_mb *doe_mb,
604 struct pci_doe_task *task)
605{
606 if (!pci_doe_supports_prot(doe_mb, task->prot.vid, task->prot.type))
607 return -EINVAL;
608
609 if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags))
610 return -EIO;
611
612 task->doe_mb = doe_mb;
613 INIT_WORK_ONSTACK(&task->work, doe_statemachine_work);
614 queue_work(doe_mb->work_queue, &task->work);
615 return 0;
616}
617
618/**
619 * pci_doe() - Perform Data Object Exchange
620 *
621 * @doe_mb: DOE Mailbox
622 * @vendor: Vendor ID
623 * @type: Data Object Type
624 * @request: Request payload
625 * @request_sz: Size of request payload (bytes)
626 * @response: Response payload
627 * @response_sz: Size of response payload (bytes)
628 *
629 * Submit @request to @doe_mb and store the @response.
630 * The DOE exchange is performed synchronously and may therefore sleep.
631 *
632 * Payloads are treated as opaque byte streams which are transmitted verbatim,
633 * without byte-swapping. If payloads contain little-endian register values,
634 * the caller is responsible for conversion with cpu_to_le32() / le32_to_cpu().
635 *
636 * For convenience, arbitrary payload sizes are allowed even though PCIe r6.0
637 * sec 6.30.1 specifies the Data Object Header 2 "Length" in dwords. The last
638 * (partial) dword is copied with byte granularity and padded with zeroes if
639 * necessary. Callers are thus relieved of using dword-sized bounce buffers.
640 *
641 * RETURNS: Length of received response or negative errno.
642 * Received data in excess of @response_sz is discarded.
643 * The length may be smaller than @response_sz and the caller
644 * is responsible for checking that.
645 */
646int pci_doe(struct pci_doe_mb *doe_mb, u16 vendor, u8 type,
647 const void *request, size_t request_sz,
648 void *response, size_t response_sz)
649{
650 DECLARE_COMPLETION_ONSTACK(c);
651 struct pci_doe_task task = {
652 .prot.vid = vendor,
653 .prot.type = type,
654 .request_pl = request,
655 .request_pl_sz = request_sz,
656 .response_pl = response,
657 .response_pl_sz = response_sz,
658 .complete = pci_doe_task_complete,
659 .private = &c,
660 };
661 int rc;
662
663 rc = pci_doe_submit_task(doe_mb, &task);
664 if (rc)
665 return rc;
666
667 wait_for_completion(&c);
668
669 return task.rv;
670}
671EXPORT_SYMBOL_GPL(pci_doe);
672
673/**
674 * pci_find_doe_mailbox() - Find Data Object Exchange mailbox
675 *
676 * @pdev: PCI device
677 * @vendor: Vendor ID
678 * @type: Data Object Type
679 *
680 * Find first DOE mailbox of a PCI device which supports the given protocol.
681 *
682 * RETURNS: Pointer to the DOE mailbox or NULL if none was found.
683 */
684struct pci_doe_mb *pci_find_doe_mailbox(struct pci_dev *pdev, u16 vendor,
685 u8 type)
686{
687 struct pci_doe_mb *doe_mb;
688 unsigned long index;
689
690 xa_for_each(&pdev->doe_mbs, index, doe_mb)
691 if (pci_doe_supports_prot(doe_mb, vendor, type))
692 return doe_mb;
693
694 return NULL;
695}
696EXPORT_SYMBOL_GPL(pci_find_doe_mailbox);
697
698void pci_doe_init(struct pci_dev *pdev)
699{
700 struct pci_doe_mb *doe_mb;
701 u16 offset = 0;
702 int rc;
703
704 xa_init(&pdev->doe_mbs);
705
706 while ((offset = pci_find_next_ext_capability(pdev, offset,
707 PCI_EXT_CAP_ID_DOE))) {
708 doe_mb = pci_doe_create_mb(pdev, offset);
709 if (IS_ERR(doe_mb)) {
710 pci_err(pdev, "[%x] failed to create mailbox: %ld\n",
711 offset, PTR_ERR(doe_mb));
712 continue;
713 }
714
715 rc = xa_insert(&pdev->doe_mbs, offset, doe_mb, GFP_KERNEL);
716 if (rc) {
717 pci_err(pdev, "[%x] failed to insert mailbox: %d\n",
718 offset, rc);
719 pci_doe_destroy_mb(doe_mb);
720 }
721 }
722}
723
724void pci_doe_destroy(struct pci_dev *pdev)
725{
726 struct pci_doe_mb *doe_mb;
727 unsigned long index;
728
729 xa_for_each(&pdev->doe_mbs, index, doe_mb)
730 pci_doe_destroy_mb(doe_mb);
731
732 xa_destroy(&pdev->doe_mbs);
733}
734
735void pci_doe_disconnected(struct pci_dev *pdev)
736{
737 struct pci_doe_mb *doe_mb;
738 unsigned long index;
739
740 xa_for_each(&pdev->doe_mbs, index, doe_mb)
741 pci_doe_cancel_tasks(doe_mb);
742}